1HXCOMM Use DEFHEADING() to define headings in both help text and rST. 2HXCOMM Text between SRST and ERST is copied to the rST version and 3HXCOMM discarded from C version. 4HXCOMM DEF(option, HAS_ARG/0, opt_enum, opt_help, arch_mask) is used to 5HXCOMM construct option structures, enums and help message for specified 6HXCOMM architectures. 7HXCOMM HXCOMM can be used for comments, discarded from both rST and C. 8 9DEFHEADING(Standard options:) 10 11DEF("help", 0, QEMU_OPTION_h, 12 "-h or -help display this help and exit\n", QEMU_ARCH_ALL) 13SRST 14``-h`` 15 Display help and exit 16ERST 17 18DEF("version", 0, QEMU_OPTION_version, 19 "-version display version information and exit\n", QEMU_ARCH_ALL) 20SRST 21``-version`` 22 Display version information and exit 23ERST 24 25DEF("machine", HAS_ARG, QEMU_OPTION_machine, \ 26 "-machine [type=]name[,prop[=value][,...]]\n" 27 " selects emulated machine ('-machine help' for list)\n" 28 " property accel=accel1[:accel2[:...]] selects accelerator\n" 29 " supported accelerators are kvm, xen, hax, hvf, nvmm, whpx or tcg (default: tcg)\n" 30 " vmport=on|off|auto controls emulation of vmport (default: auto)\n" 31 " dump-guest-core=on|off include guest memory in a core dump (default=on)\n" 32 " mem-merge=on|off controls memory merge support (default: on)\n" 33 " aes-key-wrap=on|off controls support for AES key wrapping (default=on)\n" 34 " dea-key-wrap=on|off controls support for DEA key wrapping (default=on)\n" 35 " suppress-vmdesc=on|off disables self-describing migration (default=off)\n" 36 " nvdimm=on|off controls NVDIMM support (default=off)\n" 37 " memory-encryption=@var{} memory encryption object to use (default=none)\n" 38 " hmat=on|off controls ACPI HMAT support (default=off)\n" 39 " memory-backend='backend-id' specifies explicitly provided backend for main RAM (default=none)\n" 40 " cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]\n" 41 " zpcii-disable=on|off disables zPCI interpretation facilities (default=off)\n", 42 QEMU_ARCH_ALL) 43SRST 44``-machine [type=]name[,prop=value[,...]]`` 45 Select the emulated machine by name. Use ``-machine help`` to list 46 available machines. 47 48 For architectures which aim to support live migration compatibility 49 across releases, each release will introduce a new versioned machine 50 type. For example, the 2.8.0 release introduced machine types 51 "pc-i440fx-2.8" and "pc-q35-2.8" for the x86\_64/i686 architectures. 52 53 To allow live migration of guests from QEMU version 2.8.0, to QEMU 54 version 2.9.0, the 2.9.0 version must support the "pc-i440fx-2.8" 55 and "pc-q35-2.8" machines too. To allow users live migrating VMs to 56 skip multiple intermediate releases when upgrading, new releases of 57 QEMU will support machine types from many previous versions. 58 59 Supported machine properties are: 60 61 ``accel=accels1[:accels2[:...]]`` 62 This is used to enable an accelerator. Depending on the target 63 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. 64 By default, tcg is used. If there is more than one accelerator 65 specified, the next one is used if the previous one fails to 66 initialize. 67 68 ``vmport=on|off|auto`` 69 Enables emulation of VMWare IO port, for vmmouse etc. auto says 70 to select the value based on accel. For accel=xen the default is 71 off otherwise the default is on. 72 73 ``dump-guest-core=on|off`` 74 Include guest memory in a core dump. The default is on. 75 76 ``mem-merge=on|off`` 77 Enables or disables memory merge support. This feature, when 78 supported by the host, de-duplicates identical memory pages 79 among VMs instances (enabled by default). 80 81 ``aes-key-wrap=on|off`` 82 Enables or disables AES key wrapping support on s390-ccw hosts. 83 This feature controls whether AES wrapping keys will be created 84 to allow execution of AES cryptographic functions. The default 85 is on. 86 87 ``dea-key-wrap=on|off`` 88 Enables or disables DEA key wrapping support on s390-ccw hosts. 89 This feature controls whether DEA wrapping keys will be created 90 to allow execution of DEA cryptographic functions. The default 91 is on. 92 93 ``nvdimm=on|off`` 94 Enables or disables NVDIMM support. The default is off. 95 96 ``memory-encryption=`` 97 Memory encryption object to use. The default is none. 98 99 ``hmat=on|off`` 100 Enables or disables ACPI Heterogeneous Memory Attribute Table 101 (HMAT) support. The default is off. 102 103 ``memory-backend='id'`` 104 An alternative to legacy ``-mem-path`` and ``mem-prealloc`` options. 105 Allows to use a memory backend as main RAM. 106 107 For example: 108 :: 109 110 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on 111 -machine memory-backend=pc.ram 112 -m 512M 113 114 Migration compatibility note: 115 116 * as backend id one shall use value of 'default-ram-id', advertised by 117 machine type (available via ``query-machines`` QMP command), if migration 118 to/from old QEMU (<5.0) is expected. 119 * for machine types 4.0 and older, user shall 120 use ``x-use-canonical-path-for-ramblock-id=off`` backend option 121 if migration to/from old QEMU (<5.0) is expected. 122 123 For example: 124 :: 125 126 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off 127 -machine memory-backend=pc.ram 128 -m 512M 129 130 ``cxl-fmw.0.targets.0=firsttarget,cxl-fmw.0.targets.1=secondtarget,cxl-fmw.0.size=size[,cxl-fmw.0.interleave-granularity=granularity]`` 131 Define a CXL Fixed Memory Window (CFMW). 132 133 Described in the CXL 2.0 ECN: CEDT CFMWS & QTG _DSM. 134 135 They are regions of Host Physical Addresses (HPA) on a system which 136 may be interleaved across one or more CXL host bridges. The system 137 software will assign particular devices into these windows and 138 configure the downstream Host-managed Device Memory (HDM) decoders 139 in root ports, switch ports and devices appropriately to meet the 140 interleave requirements before enabling the memory devices. 141 142 ``targets.X=target`` provides the mapping to CXL host bridges 143 which may be identified by the id provied in the -device entry. 144 Multiple entries are needed to specify all the targets when 145 the fixed memory window represents interleaved memory. X is the 146 target index from 0. 147 148 ``size=size`` sets the size of the CFMW. This must be a multiple of 149 256MiB. The region will be aligned to 256MiB but the location is 150 platform and configuration dependent. 151 152 ``interleave-granularity=granularity`` sets the granularity of 153 interleave. Default 256KiB. Only 256KiB, 512KiB, 1024KiB, 2048KiB 154 4096KiB, 8192KiB and 16384KiB granularities supported. 155 156 Example: 157 158 :: 159 160 -machine cxl-fmw.0.targets.0=cxl.0,cxl-fmw.0.targets.1=cxl.1,cxl-fmw.0.size=128G,cxl-fmw.0.interleave-granularity=512k 161 162 ``zpcii-disable=on|off`` 163 Disables zPCI interpretation facilties on s390-ccw hosts. 164 This feature can be used to disable hardware virtual assists 165 related to zPCI devices. The default is off. 166ERST 167 168DEF("M", HAS_ARG, QEMU_OPTION_M, 169 " sgx-epc.0.memdev=memid,sgx-epc.0.node=numaid\n", 170 QEMU_ARCH_ALL) 171 172SRST 173``sgx-epc.0.memdev=@var{memid},sgx-epc.0.node=@var{numaid}`` 174 Define an SGX EPC section. 175ERST 176 177DEF("cpu", HAS_ARG, QEMU_OPTION_cpu, 178 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL) 179SRST 180``-cpu model`` 181 Select CPU model (``-cpu help`` for list and additional feature 182 selection) 183ERST 184 185DEF("accel", HAS_ARG, QEMU_OPTION_accel, 186 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 187 " select accelerator (kvm, xen, hax, hvf, nvmm, whpx or tcg; use 'help' for a list)\n" 188 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 189 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 190 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 191 " split-wx=on|off (enable TCG split w^x mapping)\n" 192 " tb-size=n (TCG translation block cache size)\n" 193 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" 194 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) 195SRST 196``-accel name[,prop=value[,...]]`` 197 This is used to enable an accelerator. Depending on the target 198 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. By 199 default, tcg is used. If there is more than one accelerator 200 specified, the next one is used if the previous one fails to 201 initialize. 202 203 ``igd-passthru=on|off`` 204 When Xen is in use, this option controls whether Intel 205 integrated graphics devices can be passed through to the guest 206 (default=off) 207 208 ``kernel-irqchip=on|off|split`` 209 Controls KVM in-kernel irqchip support. The default is full 210 acceleration of the interrupt controllers. On x86, split irqchip 211 reduces the kernel attack surface, at a performance cost for 212 non-MSI interrupts. Disabling the in-kernel irqchip completely 213 is not recommended except for debugging purposes. 214 215 ``kvm-shadow-mem=size`` 216 Defines the size of the KVM shadow MMU. 217 218 ``split-wx=on|off`` 219 Controls the use of split w^x mapping for the TCG code generation 220 buffer. Some operating systems require this to be enabled, and in 221 such a case this will default on. On other operating systems, this 222 will default off, but one may enable this for testing or debugging. 223 224 ``tb-size=n`` 225 Controls the size (in MiB) of the TCG translation block cache. 226 227 ``thread=single|multi`` 228 Controls number of TCG threads. When the TCG is multi-threaded 229 there will be one thread per vCPU therefore taking advantage of 230 additional host cores. The default is to enable multi-threading 231 where both the back-end and front-ends support it and no 232 incompatible TCG features have been enabled (e.g. 233 icount/replay). 234 235 ``dirty-ring-size=n`` 236 When the KVM accelerator is used, it controls the size of the per-vCPU 237 dirty page ring buffer (number of entries for each vCPU). It should 238 be a value that is power of two, and it should be 1024 or bigger (but 239 still less than the maximum value that the kernel supports). 4096 240 could be a good initial value if you have no idea which is the best. 241 Set this value to 0 to disable the feature. By default, this feature 242 is disabled (dirty-ring-size=0). When enabled, KVM will instead 243 record dirty pages in a bitmap. 244 245ERST 246 247DEF("smp", HAS_ARG, QEMU_OPTION_smp, 248 "-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]\n" 249 " set the number of initial CPUs to 'n' [default=1]\n" 250 " maxcpus= maximum number of total CPUs, including\n" 251 " offline CPUs for hotplug, etc\n" 252 " sockets= number of sockets on the machine board\n" 253 " dies= number of dies in one socket\n" 254 " clusters= number of clusters in one die\n" 255 " cores= number of cores in one cluster\n" 256 " threads= number of threads in one core\n" 257 "Note: Different machines may have different subsets of the CPU topology\n" 258 " parameters supported, so the actual meaning of the supported parameters\n" 259 " will vary accordingly. For example, for a machine type that supports a\n" 260 " three-level CPU hierarchy of sockets/cores/threads, the parameters will\n" 261 " sequentially mean as below:\n" 262 " sockets means the number of sockets on the machine board\n" 263 " cores means the number of cores in one socket\n" 264 " threads means the number of threads in one core\n" 265 " For a particular machine type board, an expected CPU topology hierarchy\n" 266 " can be defined through the supported sub-option. Unsupported parameters\n" 267 " can also be provided in addition to the sub-option, but their values\n" 268 " must be set as 1 in the purpose of correct parsing.\n", 269 QEMU_ARCH_ALL) 270SRST 271``-smp [[cpus=]n][,maxcpus=maxcpus][,sockets=sockets][,dies=dies][,clusters=clusters][,cores=cores][,threads=threads]`` 272 Simulate a SMP system with '\ ``n``\ ' CPUs initially present on 273 the machine type board. On boards supporting CPU hotplug, the optional 274 '\ ``maxcpus``\ ' parameter can be set to enable further CPUs to be 275 added at runtime. When both parameters are omitted, the maximum number 276 of CPUs will be calculated from the provided topology members and the 277 initial CPU count will match the maximum number. When only one of them 278 is given then the omitted one will be set to its counterpart's value. 279 Both parameters may be specified, but the maximum number of CPUs must 280 be equal to or greater than the initial CPU count. Product of the 281 CPU topology hierarchy must be equal to the maximum number of CPUs. 282 Both parameters are subject to an upper limit that is determined by 283 the specific machine type chosen. 284 285 To control reporting of CPU topology information, values of the topology 286 parameters can be specified. Machines may only support a subset of the 287 parameters and different machines may have different subsets supported 288 which vary depending on capacity of the corresponding CPU targets. So 289 for a particular machine type board, an expected topology hierarchy can 290 be defined through the supported sub-option. Unsupported parameters can 291 also be provided in addition to the sub-option, but their values must be 292 set as 1 in the purpose of correct parsing. 293 294 Either the initial CPU count, or at least one of the topology parameters 295 must be specified. The specified parameters must be greater than zero, 296 explicit configuration like "cpus=0" is not allowed. Values for any 297 omitted parameters will be computed from those which are given. 298 299 For example, the following sub-option defines a CPU topology hierarchy 300 (2 sockets totally on the machine, 2 cores per socket, 2 threads per 301 core) for a machine that only supports sockets/cores/threads. 302 Some members of the option can be omitted but their values will be 303 automatically computed: 304 305 :: 306 307 -smp 8,sockets=2,cores=2,threads=2,maxcpus=8 308 309 The following sub-option defines a CPU topology hierarchy (2 sockets 310 totally on the machine, 2 dies per socket, 2 cores per die, 2 threads 311 per core) for PC machines which support sockets/dies/cores/threads. 312 Some members of the option can be omitted but their values will be 313 automatically computed: 314 315 :: 316 317 -smp 16,sockets=2,dies=2,cores=2,threads=2,maxcpus=16 318 319 The following sub-option defines a CPU topology hierarchy (2 sockets 320 totally on the machine, 2 clusters per socket, 2 cores per cluster, 321 2 threads per core) for ARM virt machines which support sockets/clusters 322 /cores/threads. Some members of the option can be omitted but their values 323 will be automatically computed: 324 325 :: 326 327 -smp 16,sockets=2,clusters=2,cores=2,threads=2,maxcpus=16 328 329 Historically preference was given to the coarsest topology parameters 330 when computing missing values (ie sockets preferred over cores, which 331 were preferred over threads), however, this behaviour is considered 332 liable to change. Prior to 6.2 the preference was sockets over cores 333 over threads. Since 6.2 the preference is cores over sockets over threads. 334 335 For example, the following option defines a machine board with 2 sockets 336 of 1 core before 6.2 and 1 socket of 2 cores after 6.2: 337 338 :: 339 340 -smp 2 341ERST 342 343DEF("numa", HAS_ARG, QEMU_OPTION_numa, 344 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 345 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 346 "-numa dist,src=source,dst=destination,val=distance\n" 347 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 348 "-numa hmat-lb,initiator=node,target=node,hierarchy=memory|first-level|second-level|third-level,data-type=access-latency|read-latency|write-latency[,latency=lat][,bandwidth=bw]\n" 349 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 350 QEMU_ARCH_ALL) 351SRST 352``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 353 \ 354``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 355 \ 356``-numa dist,src=source,dst=destination,val=distance`` 357 \ 358``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 359 \ 360``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=tpye[,latency=lat][,bandwidth=bw]`` 361 \ 362``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 363 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 364 distance from a source node to a destination node. Set the ACPI 365 Heterogeneous Memory Attributes for the given nodes. 366 367 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 368 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 369 contiguous range of CPU indexes (or a single VCPU if lastcpu is 370 omitted). A non-contiguous set of VCPUs can be represented by 371 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 372 omitted on all nodes, VCPUs are automatically split between them. 373 374 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 375 NUMA node: 376 377 :: 378 379 -numa node,cpus=0-2,cpus=5 380 381 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 382 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 383 assign CPU objects to a node using topology layout properties of 384 CPU. The set of properties is machine specific, and depends on used 385 machine type/'\ ``smp``\ ' options. It could be queried with 386 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 387 property specifies node to which CPU object will be assigned, it's 388 required for node to be declared with '\ ``node``\ ' option before 389 it's used with '\ ``cpu``\ ' option. 390 391 For example: 392 393 :: 394 395 -M pc \ 396 -smp 1,sockets=2,maxcpus=2 \ 397 -numa node,nodeid=0 -numa node,nodeid=1 \ 398 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 399 400 Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported 401 for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from 402 a given memory backend device to a node. If '\ ``mem``\ ' and 403 '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them. 404 405 406 '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive. 407 Furthermore, if one node uses '\ ``memdev``\ ', all of them have to 408 use it. 409 410 '\ ``initiator``\ ' is an additional option that points to an 411 initiator NUMA node that has best performance (the lowest latency or 412 largest bandwidth) to this NUMA node. Note that this option can be 413 set only when the machine property 'hmat' is set to 'on'. 414 415 Following example creates a machine with 2 NUMA nodes, node 0 has 416 CPU. node 1 has only memory, and its initiator is node 0. Note that 417 because node 0 has CPU, by default the initiator of node 0 is itself 418 and must be itself. 419 420 :: 421 422 -machine hmat=on \ 423 -m 2G,slots=2,maxmem=4G \ 424 -object memory-backend-ram,size=1G,id=m0 \ 425 -object memory-backend-ram,size=1G,id=m1 \ 426 -numa node,nodeid=0,memdev=m0 \ 427 -numa node,nodeid=1,memdev=m1,initiator=0 \ 428 -smp 2,sockets=2,maxcpus=2 \ 429 -numa cpu,node-id=0,socket-id=0 \ 430 -numa cpu,node-id=0,socket-id=1 431 432 source and destination are NUMA node IDs. distance is the NUMA 433 distance from source to destination. The distance from a node to 434 itself is always 10. If any pair of nodes is given a distance, then 435 all pairs must be given distances. Although, when distances are only 436 given in one direction for each pair of nodes, then the distances in 437 the opposite directions are assumed to be the same. If, however, an 438 asymmetrical pair of distances is given for even one node pair, then 439 all node pairs must be provided distance values for both directions, 440 even when they are symmetrical. When a node is unreachable from 441 another node, set the pair's distance to 255. 442 443 Note that the -``numa`` option doesn't allocate any of the specified 444 resources, it just assigns existing resources to NUMA nodes. This 445 means that one still has to use the ``-m``, ``-smp`` options to 446 allocate RAM and VCPUs respectively. 447 448 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 449 Information between initiator and target NUMA nodes in ACPI 450 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 451 create memory requests, usually it has one or more processors. 452 Target NUMA node contains addressable memory. 453 454 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 455 the memory hierarchy of the target NUMA node: if hierarchy is 456 'memory', the structure represents the memory performance; if 457 hierarchy is 'first-level\|second-level\|third-level', this 458 structure represents aggregated performance of memory side caches 459 for each domain. type of 'data-type' is type of data represented by 460 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 461 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 462 the target memory; if 'hierarchy' is 463 'first-level\|second-level\|third-level', 'data-type' is 464 'access\|read\|write' hit latency or 'access\|read\|write' hit 465 bandwidth of the target memory side cache. 466 467 lat is latency value in nanoseconds. bw is bandwidth value, the 468 possible value and units are NUM[M\|G\|T], mean that the bandwidth 469 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 470 used suffix). Note that if latency or bandwidth value is 0, means 471 the corresponding latency or bandwidth information is not provided. 472 473 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 474 belongs. size is the size of memory side cache in bytes. level is 475 the cache level described in this structure, note that the cache 476 level 0 should not be used with '\ ``hmat-cache``\ ' option. 477 associativity is the cache associativity, the possible value is 478 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 479 is the write policy. line is the cache Line size in bytes. 480 481 For example, the following options describe 2 NUMA nodes. Node 0 has 482 2 cpus and a ram, node 1 has only a ram. The processors in node 0 483 access memory in node 0 with access-latency 5 nanoseconds, 484 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 485 memory in NUMA node 1 with access-latency 10 nanoseconds, 486 access-bandwidth is 100 MB/s. And for memory side cache information, 487 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 488 policy is write-back, the cache Line size is 8 bytes: 489 490 :: 491 492 -machine hmat=on \ 493 -m 2G \ 494 -object memory-backend-ram,size=1G,id=m0 \ 495 -object memory-backend-ram,size=1G,id=m1 \ 496 -smp 2,sockets=2,maxcpus=2 \ 497 -numa node,nodeid=0,memdev=m0 \ 498 -numa node,nodeid=1,memdev=m1,initiator=0 \ 499 -numa cpu,node-id=0,socket-id=0 \ 500 -numa cpu,node-id=0,socket-id=1 \ 501 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 502 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 503 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 504 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 505 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 506 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 507ERST 508 509DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 510 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 511 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 512SRST 513``-add-fd fd=fd,set=set[,opaque=opaque]`` 514 Add a file descriptor to an fd set. Valid options are: 515 516 ``fd=fd`` 517 This option defines the file descriptor of which a duplicate is 518 added to fd set. The file descriptor cannot be stdin, stdout, or 519 stderr. 520 521 ``set=set`` 522 This option defines the ID of the fd set to add the file 523 descriptor to. 524 525 ``opaque=opaque`` 526 This option defines a free-form string that can be used to 527 describe fd. 528 529 You can open an image using pre-opened file descriptors from an fd 530 set: 531 532 .. parsed-literal:: 533 534 |qemu_system| \\ 535 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 536 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 537 -drive file=/dev/fdset/2,index=0,media=disk 538ERST 539 540DEF("set", HAS_ARG, QEMU_OPTION_set, 541 "-set group.id.arg=value\n" 542 " set <arg> parameter for item <id> of type <group>\n" 543 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 544SRST 545``-set group.id.arg=value`` 546 Set parameter arg for item id of type group 547ERST 548 549DEF("global", HAS_ARG, QEMU_OPTION_global, 550 "-global driver.property=value\n" 551 "-global driver=driver,property=property,value=value\n" 552 " set a global default for a driver property\n", 553 QEMU_ARCH_ALL) 554SRST 555``-global driver.prop=value`` 556 \ 557``-global driver=driver,property=property,value=value`` 558 Set default value of driver's property prop to value, e.g.: 559 560 .. parsed-literal:: 561 562 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 563 564 In particular, you can use this to set driver properties for devices 565 which are created automatically by the machine model. To create a 566 device which is not created automatically and set properties on it, 567 use -``device``. 568 569 -global driver.prop=value is shorthand for -global 570 driver=driver,property=prop,value=value. The longhand syntax works 571 even when driver contains a dot. 572ERST 573 574DEF("boot", HAS_ARG, QEMU_OPTION_boot, 575 "-boot [order=drives][,once=drives][,menu=on|off]\n" 576 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 577 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 578 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 579 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 580 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 581 QEMU_ARCH_ALL) 582SRST 583``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 584 Specify boot order drives as a string of drive letters. Valid drive 585 letters depend on the target architecture. The x86 PC uses: a, b 586 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 587 (Etherboot from network adapter 1-4), hard disk boot is the default. 588 To apply a particular boot order only on the first startup, specify 589 it via ``once``. Note that the ``order`` or ``once`` parameter 590 should not be used together with the ``bootindex`` property of 591 devices, since the firmware implementations normally do not support 592 both at the same time. 593 594 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 595 as firmware/BIOS supports them. The default is non-interactive boot. 596 597 A splash picture could be passed to bios, enabling user to show it 598 as logo, when option splash=sp\_name is given and menu=on, If 599 firmware/BIOS supports them. Currently Seabios for X86 system 600 support it. limitation: The splash file could be a jpeg file or a 601 BMP file in 24 BPP format(true color). The resolution should be 602 supported by the SVGA mode, so the recommended is 320x240, 640x480, 603 800x640. 604 605 A timeout could be passed to bios, guest will pause for rb\_timeout 606 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 607 not reboot, qemu passes '-1' to bios by default. Currently Seabios 608 for X86 system support it. 609 610 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 611 it. This only effects when boot priority is changed by bootindex 612 options. The default is non-strict boot. 613 614 .. parsed-literal:: 615 616 # try to boot from network first, then from hard disk 617 |qemu_system_x86| -boot order=nc 618 # boot from CD-ROM first, switch back to default order after reboot 619 |qemu_system_x86| -boot once=d 620 # boot with a splash picture for 5 seconds. 621 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 622 623 Note: The legacy format '-boot drives' is still supported but its 624 use is discouraged as it may be removed from future versions. 625ERST 626 627DEF("m", HAS_ARG, QEMU_OPTION_m, 628 "-m [size=]megs[,slots=n,maxmem=size]\n" 629 " configure guest RAM\n" 630 " size: initial amount of guest memory\n" 631 " slots: number of hotplug slots (default: none)\n" 632 " maxmem: maximum amount of guest memory (default: none)\n" 633 "NOTE: Some architectures might enforce a specific granularity\n", 634 QEMU_ARCH_ALL) 635SRST 636``-m [size=]megs[,slots=n,maxmem=size]`` 637 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 638 Optionally, a suffix of "M" or "G" can be used to signify a value in 639 megabytes or gigabytes respectively. Optional pair slots, maxmem 640 could be used to set amount of hotpluggable memory slots and maximum 641 amount of memory. Note that maxmem must be aligned to the page size. 642 643 For example, the following command-line sets the guest startup RAM 644 size to 1GB, creates 3 slots to hotplug additional memory and sets 645 the maximum memory the guest can reach to 4GB: 646 647 .. parsed-literal:: 648 649 |qemu_system| -m 1G,slots=3,maxmem=4G 650 651 If slots and maxmem are not specified, memory hotplug won't be 652 enabled and the guest startup RAM will never increase. 653ERST 654 655DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 656 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 657SRST 658``-mem-path path`` 659 Allocate guest RAM from a temporarily created file in path. 660ERST 661 662DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 663 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 664 QEMU_ARCH_ALL) 665SRST 666``-mem-prealloc`` 667 Preallocate memory when using -mem-path. 668ERST 669 670DEF("k", HAS_ARG, QEMU_OPTION_k, 671 "-k language use keyboard layout (for example 'fr' for French)\n", 672 QEMU_ARCH_ALL) 673SRST 674``-k language`` 675 Use keyboard layout language (for example ``fr`` for French). This 676 option is only needed where it is not easy to get raw PC keycodes 677 (e.g. on Macs, with some X11 servers or with a VNC or curses 678 display). You don't normally need to use it on PC/Linux or 679 PC/Windows hosts. 680 681 The available layouts are: 682 683 :: 684 685 ar de-ch es fo fr-ca hu ja mk no pt-br sv 686 da en-gb et fr fr-ch is lt nl pl ru th 687 de en-us fi fr-be hr it lv nl-be pt sl tr 688 689 The default is ``en-us``. 690ERST 691 692 693HXCOMM Deprecated by -audiodev 694DEF("audio-help", 0, QEMU_OPTION_audio_help, 695 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 696 QEMU_ARCH_ALL) 697SRST 698``-audio-help`` 699 Will show the -audiodev equivalent of the currently specified 700 (deprecated) environment variables. 701ERST 702 703DEF("audio", HAS_ARG, QEMU_OPTION_audio, 704 "-audio [driver=]driver,model=value[,prop[=value][,...]]\n" 705 " specifies the audio backend and device to use;\n" 706 " apart from 'model', options are the same as for -audiodev.\n" 707 " use '-audio model=help' to show possible devices.\n", 708 QEMU_ARCH_ALL) 709SRST 710``-audio [driver=]driver,model=value[,prop[=value][,...]]`` 711 This option is a shortcut for configuring both the guest audio 712 hardware and the host audio backend in one go. 713 The driver option is the same as with the corresponding ``-audiodev`` option below. 714 The guest hardware model can be set with ``model=modelname``. 715 716 Use ``driver=help`` to list the available drivers, 717 and ``model=help`` to list the available device types. 718 719 The following two example do exactly the same, to show how ``-audio`` 720 can be used to shorten the command line length: 721 722 .. parsed-literal:: 723 724 |qemu_system| -audiodev pa,id=pa -device sb16,audiodev=pa 725 |qemu_system| -audio pa,model=sb16 726ERST 727 728DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 729 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 730 " specifies the audio backend to use\n" 731 " Use ``-audiodev help`` to list the available drivers\n" 732 " id= identifier of the backend\n" 733 " timer-period= timer period in microseconds\n" 734 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 735 " in|out.fixed-settings= use fixed settings for host audio\n" 736 " in|out.frequency= frequency to use with fixed settings\n" 737 " in|out.channels= number of channels to use with fixed settings\n" 738 " in|out.format= sample format to use with fixed settings\n" 739 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 740 " in|out.voices= number of voices to use\n" 741 " in|out.buffer-length= length of buffer in microseconds\n" 742 "-audiodev none,id=id,[,prop[=value][,...]]\n" 743 " dummy driver that discards all output\n" 744#ifdef CONFIG_AUDIO_ALSA 745 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 746 " in|out.dev= name of the audio device to use\n" 747 " in|out.period-length= length of period in microseconds\n" 748 " in|out.try-poll= attempt to use poll mode\n" 749 " threshold= threshold (in microseconds) when playback starts\n" 750#endif 751#ifdef CONFIG_AUDIO_COREAUDIO 752 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 753 " in|out.buffer-count= number of buffers\n" 754#endif 755#ifdef CONFIG_AUDIO_DSOUND 756 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 757 " latency= add extra latency to playback in microseconds\n" 758#endif 759#ifdef CONFIG_AUDIO_OSS 760 "-audiodev oss,id=id[,prop[=value][,...]]\n" 761 " in|out.dev= path of the audio device to use\n" 762 " in|out.buffer-count= number of buffers\n" 763 " in|out.try-poll= attempt to use poll mode\n" 764 " try-mmap= try using memory mapped access\n" 765 " exclusive= open device in exclusive mode\n" 766 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 767#endif 768#ifdef CONFIG_AUDIO_PA 769 "-audiodev pa,id=id[,prop[=value][,...]]\n" 770 " server= PulseAudio server address\n" 771 " in|out.name= source/sink device name\n" 772 " in|out.latency= desired latency in microseconds\n" 773#endif 774#ifdef CONFIG_AUDIO_SDL 775 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 776 " in|out.buffer-count= number of buffers\n" 777#endif 778#ifdef CONFIG_AUDIO_SNDIO 779 "-audiodev sndio,id=id[,prop[=value][,...]]\n" 780#endif 781#ifdef CONFIG_SPICE 782 "-audiodev spice,id=id[,prop[=value][,...]]\n" 783#endif 784#ifdef CONFIG_DBUS_DISPLAY 785 "-audiodev dbus,id=id[,prop[=value][,...]]\n" 786#endif 787 "-audiodev wav,id=id[,prop[=value][,...]]\n" 788 " path= path of wav file to record\n", 789 QEMU_ARCH_ALL) 790SRST 791``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 792 Adds a new audio backend driver identified by id. There are global 793 and driver specific properties. Some values can be set differently 794 for input and output, they're marked with ``in|out.``. You can set 795 the input's property with ``in.prop`` and the output's property with 796 ``out.prop``. For example: 797 798 :: 799 800 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 801 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 802 803 NOTE: parameter validation is known to be incomplete, in many cases 804 specifying an invalid option causes QEMU to print an error message 805 and continue emulation without sound. 806 807 Valid global options are: 808 809 ``id=identifier`` 810 Identifies the audio backend. 811 812 ``timer-period=period`` 813 Sets the timer period used by the audio subsystem in 814 microseconds. Default is 10000 (10 ms). 815 816 ``in|out.mixing-engine=on|off`` 817 Use QEMU's mixing engine to mix all streams inside QEMU and 818 convert audio formats when not supported by the backend. When 819 off, fixed-settings must be off too. Note that disabling this 820 option means that the selected backend must support multiple 821 streams and the audio formats used by the virtual cards, 822 otherwise you'll get no sound. It's not recommended to disable 823 this option unless you want to use 5.1 or 7.1 audio, as mixing 824 engine only supports mono and stereo audio. Default is on. 825 826 ``in|out.fixed-settings=on|off`` 827 Use fixed settings for host audio. When off, it will change 828 based on how the guest opens the sound card. In this case you 829 must not specify frequency, channels or format. Default is on. 830 831 ``in|out.frequency=frequency`` 832 Specify the frequency to use when using fixed-settings. Default 833 is 44100Hz. 834 835 ``in|out.channels=channels`` 836 Specify the number of channels to use when using fixed-settings. 837 Default is 2 (stereo). 838 839 ``in|out.format=format`` 840 Specify the sample format to use when using fixed-settings. 841 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 842 ``u32``, ``f32``. Default is ``s16``. 843 844 ``in|out.voices=voices`` 845 Specify the number of voices to use. Default is 1. 846 847 ``in|out.buffer-length=usecs`` 848 Sets the size of the buffer in microseconds. 849 850``-audiodev none,id=id[,prop[=value][,...]]`` 851 Creates a dummy backend that discards all outputs. This backend has 852 no backend specific properties. 853 854``-audiodev alsa,id=id[,prop[=value][,...]]`` 855 Creates backend using the ALSA. This backend is only available on 856 Linux. 857 858 ALSA specific options are: 859 860 ``in|out.dev=device`` 861 Specify the ALSA device to use for input and/or output. Default 862 is ``default``. 863 864 ``in|out.period-length=usecs`` 865 Sets the period length in microseconds. 866 867 ``in|out.try-poll=on|off`` 868 Attempt to use poll mode with the device. Default is on. 869 870 ``threshold=threshold`` 871 Threshold (in microseconds) when playback starts. Default is 0. 872 873``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 874 Creates a backend using Apple's Core Audio. This backend is only 875 available on Mac OS and only supports playback. 876 877 Core Audio specific options are: 878 879 ``in|out.buffer-count=count`` 880 Sets the count of the buffers. 881 882``-audiodev dsound,id=id[,prop[=value][,...]]`` 883 Creates a backend using Microsoft's DirectSound. This backend is 884 only available on Windows and only supports playback. 885 886 DirectSound specific options are: 887 888 ``latency=usecs`` 889 Add extra usecs microseconds latency to playback. Default is 890 10000 (10 ms). 891 892``-audiodev oss,id=id[,prop[=value][,...]]`` 893 Creates a backend using OSS. This backend is available on most 894 Unix-like systems. 895 896 OSS specific options are: 897 898 ``in|out.dev=device`` 899 Specify the file name of the OSS device to use. Default is 900 ``/dev/dsp``. 901 902 ``in|out.buffer-count=count`` 903 Sets the count of the buffers. 904 905 ``in|out.try-poll=on|of`` 906 Attempt to use poll mode with the device. Default is on. 907 908 ``try-mmap=on|off`` 909 Try using memory mapped device access. Default is off. 910 911 ``exclusive=on|off`` 912 Open the device in exclusive mode (vmix won't work in this 913 case). Default is off. 914 915 ``dsp-policy=policy`` 916 Sets the timing policy (between 0 and 10, where smaller number 917 means smaller latency but higher CPU usage). Use -1 to use 918 buffer sizes specified by ``buffer`` and ``buffer-count``. This 919 option is ignored if you do not have OSS 4. Default is 5. 920 921``-audiodev pa,id=id[,prop[=value][,...]]`` 922 Creates a backend using PulseAudio. This backend is available on 923 most systems. 924 925 PulseAudio specific options are: 926 927 ``server=server`` 928 Sets the PulseAudio server to connect to. 929 930 ``in|out.name=sink`` 931 Use the specified source/sink for recording/playback. 932 933 ``in|out.latency=usecs`` 934 Desired latency in microseconds. The PulseAudio server will try 935 to honor this value but actual latencies may be lower or higher. 936 937``-audiodev sdl,id=id[,prop[=value][,...]]`` 938 Creates a backend using SDL. This backend is available on most 939 systems, but you should use your platform's native backend if 940 possible. 941 942 SDL specific options are: 943 944 ``in|out.buffer-count=count`` 945 Sets the count of the buffers. 946 947``-audiodev sndio,id=id[,prop[=value][,...]]`` 948 Creates a backend using SNDIO. This backend is available on 949 OpenBSD and most other Unix-like systems. 950 951 Sndio specific options are: 952 953 ``in|out.dev=device`` 954 Specify the sndio device to use for input and/or output. Default 955 is ``default``. 956 957 ``in|out.latency=usecs`` 958 Sets the desired period length in microseconds. 959 960``-audiodev spice,id=id[,prop[=value][,...]]`` 961 Creates a backend that sends audio through SPICE. This backend 962 requires ``-spice`` and automatically selected in that case, so 963 usually you can ignore this option. This backend has no backend 964 specific properties. 965 966``-audiodev wav,id=id[,prop[=value][,...]]`` 967 Creates a backend that writes audio to a WAV file. 968 969 Backend specific options are: 970 971 ``path=path`` 972 Write recorded audio into the specified file. Default is 973 ``qemu.wav``. 974ERST 975 976DEF("device", HAS_ARG, QEMU_OPTION_device, 977 "-device driver[,prop[=value][,...]]\n" 978 " add device (based on driver)\n" 979 " prop=value,... sets driver properties\n" 980 " use '-device help' to print all possible drivers\n" 981 " use '-device driver,help' to print all possible properties\n", 982 QEMU_ARCH_ALL) 983SRST 984``-device driver[,prop[=value][,...]]`` 985 Add device driver. prop=value sets driver properties. Valid 986 properties depend on the driver. To get help on possible drivers and 987 properties, use ``-device help`` and ``-device driver,help``. 988 989 Some drivers are: 990 991``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 992 Add an IPMI BMC. This is a simulation of a hardware management 993 interface processor that normally sits on a system. It provides a 994 watchdog and the ability to reset and power control the system. You 995 need to connect this to an IPMI interface to make it useful 996 997 The IPMI slave address to use for the BMC. The default is 0x20. This 998 address is the BMC's address on the I2C network of management 999 controllers. If you don't know what this means, it is safe to ignore 1000 it. 1001 1002 ``id=id`` 1003 The BMC id for interfaces to use this device. 1004 1005 ``slave_addr=val`` 1006 Define slave address to use for the BMC. The default is 0x20. 1007 1008 ``sdrfile=file`` 1009 file containing raw Sensor Data Records (SDR) data. The default 1010 is none. 1011 1012 ``fruareasize=val`` 1013 size of a Field Replaceable Unit (FRU) area. The default is 1014 1024. 1015 1016 ``frudatafile=file`` 1017 file containing raw Field Replaceable Unit (FRU) inventory data. 1018 The default is none. 1019 1020 ``guid=uuid`` 1021 value for the GUID for the BMC, in standard UUID format. If this 1022 is set, get "Get GUID" command to the BMC will return it. 1023 Otherwise "Get GUID" will return an error. 1024 1025``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 1026 Add a connection to an external IPMI BMC simulator. Instead of 1027 locally emulating the BMC like the above item, instead connect to an 1028 external entity that provides the IPMI services. 1029 1030 A connection is made to an external BMC simulator. If you do this, 1031 it is strongly recommended that you use the "reconnect=" chardev 1032 option to reconnect to the simulator if the connection is lost. Note 1033 that if this is not used carefully, it can be a security issue, as 1034 the interface has the ability to send resets, NMIs, and power off 1035 the VM. It's best if QEMU makes a connection to an external 1036 simulator running on a secure port on localhost, so neither the 1037 simulator nor QEMU is exposed to any outside network. 1038 1039 See the "lanserv/README.vm" file in the OpenIPMI library for more 1040 details on the external interface. 1041 1042``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 1043 Add a KCS IPMI interafce on the ISA bus. This also adds a 1044 corresponding ACPI and SMBIOS entries, if appropriate. 1045 1046 ``bmc=id`` 1047 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 1048 above. 1049 1050 ``ioport=val`` 1051 Define the I/O address of the interface. The default is 0xca0 1052 for KCS. 1053 1054 ``irq=val`` 1055 Define the interrupt to use. The default is 5. To disable 1056 interrupts, set this to 0. 1057 1058``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 1059 Like the KCS interface, but defines a BT interface. The default port 1060 is 0xe4 and the default interrupt is 5. 1061 1062``-device pci-ipmi-kcs,bmc=id`` 1063 Add a KCS IPMI interafce on the PCI bus. 1064 1065 ``bmc=id`` 1066 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 1067 1068``-device pci-ipmi-bt,bmc=id`` 1069 Like the KCS interface, but defines a BT interface on the PCI bus. 1070 1071``-device intel-iommu[,option=...]`` 1072 This is only supported by ``-machine q35``, which will enable Intel VT-d 1073 emulation within the guest. It supports below options: 1074 1075 ``intremap=on|off`` (default: auto) 1076 This enables interrupt remapping feature. It's required to enable 1077 complete x2apic. Currently it only supports kvm kernel-irqchip modes 1078 ``off`` or ``split``, while full kernel-irqchip is not yet supported. 1079 The default value is "auto", which will be decided by the mode of 1080 kernel-irqchip. 1081 1082 ``caching-mode=on|off`` (default: off) 1083 This enables caching mode for the VT-d emulated device. When 1084 caching-mode is enabled, each guest DMA buffer mapping will generate an 1085 IOTLB invalidation from the guest IOMMU driver to the vIOMMU device in 1086 a synchronous way. It is required for ``-device vfio-pci`` to work 1087 with the VT-d device, because host assigned devices requires to setup 1088 the DMA mapping on the host before guest DMA starts. 1089 1090 ``device-iotlb=on|off`` (default: off) 1091 This enables device-iotlb capability for the emulated VT-d device. So 1092 far virtio/vhost should be the only real user for this parameter, 1093 paired with ats=on configured for the device. 1094 1095 ``aw-bits=39|48`` (default: 39) 1096 This decides the address width of IOVA address space. The address 1097 space has 39 bits width for 3-level IOMMU page tables, and 48 bits for 1098 4-level IOMMU page tables. 1099 1100 Please also refer to the wiki page for general scenarios of VT-d 1101 emulation in QEMU: https://wiki.qemu.org/Features/VT-d. 1102 1103ERST 1104 1105DEF("name", HAS_ARG, QEMU_OPTION_name, 1106 "-name string1[,process=string2][,debug-threads=on|off]\n" 1107 " set the name of the guest\n" 1108 " string1 sets the window title and string2 the process name\n" 1109 " When debug-threads is enabled, individual threads are given a separate name\n" 1110 " NOTE: The thread names are for debugging and not a stable API.\n", 1111 QEMU_ARCH_ALL) 1112SRST 1113``-name name`` 1114 Sets the name of the guest. This name will be displayed in the SDL 1115 window caption. The name will also be used for the VNC server. Also 1116 optionally set the top visible process name in Linux. Naming of 1117 individual threads can also be enabled on Linux to aid debugging. 1118ERST 1119 1120DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 1121 "-uuid %08x-%04x-%04x-%04x-%012x\n" 1122 " specify machine UUID\n", QEMU_ARCH_ALL) 1123SRST 1124``-uuid uuid`` 1125 Set system UUID. 1126ERST 1127 1128DEFHEADING() 1129 1130DEFHEADING(Block device options:) 1131 1132SRST 1133The QEMU block device handling options have a long history and 1134have gone through several iterations as the feature set and complexity 1135of the block layer have grown. Many online guides to QEMU often 1136reference older and deprecated options, which can lead to confusion. 1137 1138The recommended modern way to describe disks is to use a combination of 1139``-device`` to specify the hardware device and ``-blockdev`` to 1140describe the backend. The device defines what the guest sees and the 1141backend describes how QEMU handles the data. 1142 1143ERST 1144 1145DEF("fda", HAS_ARG, QEMU_OPTION_fda, 1146 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 1147DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 1148SRST 1149``-fda file`` 1150 \ 1151``-fdb file`` 1152 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 1153 the System Emulation Users Guide). 1154ERST 1155 1156DEF("hda", HAS_ARG, QEMU_OPTION_hda, 1157 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 1158DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 1159DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 1160 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 1161DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 1162SRST 1163``-hda file`` 1164 \ 1165``-hdb file`` 1166 \ 1167``-hdc file`` 1168 \ 1169``-hdd file`` 1170 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images` 1171 chapter in the System Emulation Users Guide). 1172ERST 1173 1174DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 1175 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 1176 QEMU_ARCH_ALL) 1177SRST 1178``-cdrom file`` 1179 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 1180 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 1181 as filename. 1182ERST 1183 1184DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 1185 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 1186 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1187 " [,read-only=on|off][,auto-read-only=on|off]\n" 1188 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1189 " [,driver specific parameters...]\n" 1190 " configure a block backend\n", QEMU_ARCH_ALL) 1191SRST 1192``-blockdev option[,option[,option[,...]]]`` 1193 Define a new block driver node. Some of the options apply to all 1194 block drivers, other options are only accepted for a specific block 1195 driver. See below for a list of generic options and options for the 1196 most common block drivers. 1197 1198 Options that expect a reference to another node (e.g. ``file``) can 1199 be given in two ways. Either you specify the node name of an already 1200 existing node (file=node-name), or you define a new node inline, 1201 adding options for the referenced node after a dot 1202 (file.filename=path,file.aio=native). 1203 1204 A block driver node created with ``-blockdev`` can be used for a 1205 guest device by specifying its node name for the ``drive`` property 1206 in a ``-device`` argument that defines a block device. 1207 1208 ``Valid options for any block driver node:`` 1209 ``driver`` 1210 Specifies the block driver to use for the given node. 1211 1212 ``node-name`` 1213 This defines the name of the block driver node by which it 1214 will be referenced later. The name must be unique, i.e. it 1215 must not match the name of a different block driver node, or 1216 (if you use ``-drive`` as well) the ID of a drive. 1217 1218 If no node name is specified, it is automatically generated. 1219 The generated node name is not intended to be predictable 1220 and changes between QEMU invocations. For the top level, an 1221 explicit node name must be specified. 1222 1223 ``read-only`` 1224 Open the node read-only. Guest write attempts will fail. 1225 1226 Note that some block drivers support only read-only access, 1227 either generally or in certain configurations. In this case, 1228 the default value ``read-only=off`` does not work and the 1229 option must be specified explicitly. 1230 1231 ``auto-read-only`` 1232 If ``auto-read-only=on`` is set, QEMU may fall back to 1233 read-only usage even when ``read-only=off`` is requested, or 1234 even switch between modes as needed, e.g. depending on 1235 whether the image file is writable or whether a writing user 1236 is attached to the node. 1237 1238 ``force-share`` 1239 Override the image locking system of QEMU by forcing the 1240 node to utilize weaker shared access for permissions where 1241 it would normally request exclusive access. When there is 1242 the potential for multiple instances to have the same file 1243 open (whether this invocation of QEMU is the first or the 1244 second instance), both instances must permit shared access 1245 for the second instance to succeed at opening the file. 1246 1247 Enabling ``force-share=on`` requires ``read-only=on``. 1248 1249 ``cache.direct`` 1250 The host page cache can be avoided with ``cache.direct=on``. 1251 This will attempt to do disk IO directly to the guest's 1252 memory. QEMU may still perform an internal copy of the data. 1253 1254 ``cache.no-flush`` 1255 In case you don't care about data integrity over host 1256 failures, you can use ``cache.no-flush=on``. This option 1257 tells QEMU that it never needs to write any data to the disk 1258 but can instead keep things in cache. If anything goes 1259 wrong, like your host losing power, the disk storage getting 1260 disconnected accidentally, etc. your image will most 1261 probably be rendered unusable. 1262 1263 ``discard=discard`` 1264 discard is one of "ignore" (or "off") or "unmap" (or "on") 1265 and controls whether ``discard`` (also known as ``trim`` or 1266 ``unmap``) requests are ignored or passed to the filesystem. 1267 Some machine types may not support discard requests. 1268 1269 ``detect-zeroes=detect-zeroes`` 1270 detect-zeroes is "off", "on" or "unmap" and enables the 1271 automatic conversion of plain zero writes by the OS to 1272 driver specific optimized zero write commands. You may even 1273 choose "unmap" if discard is set to "unmap" to allow a zero 1274 write to be converted to an ``unmap`` operation. 1275 1276 ``Driver-specific options for file`` 1277 This is the protocol-level block driver for accessing regular 1278 files. 1279 1280 ``filename`` 1281 The path to the image file in the local filesystem 1282 1283 ``aio`` 1284 Specifies the AIO backend (threads/native/io_uring, 1285 default: threads) 1286 1287 ``locking`` 1288 Specifies whether the image file is protected with Linux OFD 1289 / POSIX locks. The default is to use the Linux Open File 1290 Descriptor API if available, otherwise no lock is applied. 1291 (auto/on/off, default: auto) 1292 1293 Example: 1294 1295 :: 1296 1297 -blockdev driver=file,node-name=disk,filename=disk.img 1298 1299 ``Driver-specific options for raw`` 1300 This is the image format block driver for raw images. It is 1301 usually stacked on top of a protocol level block driver such as 1302 ``file``. 1303 1304 ``file`` 1305 Reference to or definition of the data source block driver 1306 node (e.g. a ``file`` driver node) 1307 1308 Example 1: 1309 1310 :: 1311 1312 -blockdev driver=file,node-name=disk_file,filename=disk.img 1313 -blockdev driver=raw,node-name=disk,file=disk_file 1314 1315 Example 2: 1316 1317 :: 1318 1319 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1320 1321 ``Driver-specific options for qcow2`` 1322 This is the image format block driver for qcow2 images. It is 1323 usually stacked on top of a protocol level block driver such as 1324 ``file``. 1325 1326 ``file`` 1327 Reference to or definition of the data source block driver 1328 node (e.g. a ``file`` driver node) 1329 1330 ``backing`` 1331 Reference to or definition of the backing file block device 1332 (default is taken from the image file). It is allowed to 1333 pass ``null`` here in order to disable the default backing 1334 file. 1335 1336 ``lazy-refcounts`` 1337 Whether to enable the lazy refcounts feature (on/off; 1338 default is taken from the image file) 1339 1340 ``cache-size`` 1341 The maximum total size of the L2 table and refcount block 1342 caches in bytes (default: the sum of l2-cache-size and 1343 refcount-cache-size) 1344 1345 ``l2-cache-size`` 1346 The maximum size of the L2 table cache in bytes (default: if 1347 cache-size is not specified - 32M on Linux platforms, and 8M 1348 on non-Linux platforms; otherwise, as large as possible 1349 within the cache-size, while permitting the requested or the 1350 minimal refcount cache size) 1351 1352 ``refcount-cache-size`` 1353 The maximum size of the refcount block cache in bytes 1354 (default: 4 times the cluster size; or if cache-size is 1355 specified, the part of it which is not used for the L2 1356 cache) 1357 1358 ``cache-clean-interval`` 1359 Clean unused entries in the L2 and refcount caches. The 1360 interval is in seconds. The default value is 600 on 1361 supporting platforms, and 0 on other platforms. Setting it 1362 to 0 disables this feature. 1363 1364 ``pass-discard-request`` 1365 Whether discard requests to the qcow2 device should be 1366 forwarded to the data source (on/off; default: on if 1367 discard=unmap is specified, off otherwise) 1368 1369 ``pass-discard-snapshot`` 1370 Whether discard requests for the data source should be 1371 issued when a snapshot operation (e.g. deleting a snapshot) 1372 frees clusters in the qcow2 file (on/off; default: on) 1373 1374 ``pass-discard-other`` 1375 Whether discard requests for the data source should be 1376 issued on other occasions where a cluster gets freed 1377 (on/off; default: off) 1378 1379 ``overlap-check`` 1380 Which overlap checks to perform for writes to the image 1381 (none/constant/cached/all; default: cached). For details or 1382 finer granularity control refer to the QAPI documentation of 1383 ``blockdev-add``. 1384 1385 Example 1: 1386 1387 :: 1388 1389 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1390 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1391 1392 Example 2: 1393 1394 :: 1395 1396 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1397 1398 ``Driver-specific options for other drivers`` 1399 Please refer to the QAPI documentation of the ``blockdev-add`` 1400 QMP command. 1401ERST 1402 1403DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1404 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1405 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1406 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1407 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1408 " [,aio=threads|native|io_uring]\n" 1409 " [,readonly=on|off][,copy-on-read=on|off]\n" 1410 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1411 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1412 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1413 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1414 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1415 " [[,iops_size=is]]\n" 1416 " [[,group=g]]\n" 1417 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1418SRST 1419``-drive option[,option[,option[,...]]]`` 1420 Define a new drive. This includes creating a block driver node (the 1421 backend) as well as a guest device, and is mostly a shortcut for 1422 defining the corresponding ``-blockdev`` and ``-device`` options. 1423 1424 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1425 In addition, it knows the following options: 1426 1427 ``file=file`` 1428 This option defines which disk image (see the :ref:`disk images` 1429 chapter in the System Emulation Users Guide) to use with this drive. 1430 If the filename contains comma, you must double it (for instance, 1431 "file=my,,file" to use file "my,file"). 1432 1433 Special files such as iSCSI devices can be specified using 1434 protocol specific URLs. See the section for "Device URL Syntax" 1435 for more information. 1436 1437 ``if=interface`` 1438 This option defines on which type on interface the drive is 1439 connected. Available types are: ide, scsi, sd, mtd, floppy, 1440 pflash, virtio, none. 1441 1442 ``bus=bus,unit=unit`` 1443 These options define where is connected the drive by defining 1444 the bus number and the unit id. 1445 1446 ``index=index`` 1447 This option defines where the drive is connected by using an 1448 index in the list of available connectors of a given interface 1449 type. 1450 1451 ``media=media`` 1452 This option defines the type of the media: disk or cdrom. 1453 1454 ``snapshot=snapshot`` 1455 snapshot is "on" or "off" and controls snapshot mode for the 1456 given drive (see ``-snapshot``). 1457 1458 ``cache=cache`` 1459 cache is "none", "writeback", "unsafe", "directsync" or 1460 "writethrough" and controls how the host cache is used to access 1461 block data. This is a shortcut that sets the ``cache.direct`` 1462 and ``cache.no-flush`` options (as in ``-blockdev``), and 1463 additionally ``cache.writeback``, which provides a default for 1464 the ``write-cache`` option of block guest devices (as in 1465 ``-device``). The modes correspond to the following settings: 1466 1467 ============= =============== ============ ============== 1468 \ cache.writeback cache.direct cache.no-flush 1469 ============= =============== ============ ============== 1470 writeback on off off 1471 none on on off 1472 writethrough off off off 1473 directsync off on off 1474 unsafe on off on 1475 ============= =============== ============ ============== 1476 1477 The default mode is ``cache=writeback``. 1478 1479 ``aio=aio`` 1480 aio is "threads", "native", or "io_uring" and selects between pthread 1481 based disk I/O, native Linux AIO, or Linux io_uring API. 1482 1483 ``format=format`` 1484 Specify which disk format will be used rather than detecting the 1485 format. Can be used to specify format=raw to avoid interpreting 1486 an untrusted format header. 1487 1488 ``werror=action,rerror=action`` 1489 Specify which action to take on write and read errors. Valid 1490 actions are: "ignore" (ignore the error and try to continue), 1491 "stop" (pause QEMU), "report" (report the error to the guest), 1492 "enospc" (pause QEMU only if the host disk is full; report the 1493 error to the guest otherwise). The default setting is 1494 ``werror=enospc`` and ``rerror=report``. 1495 1496 ``copy-on-read=copy-on-read`` 1497 copy-on-read is "on" or "off" and enables whether to copy read 1498 backing file sectors into the image file. 1499 1500 ``bps=b,bps_rd=r,bps_wr=w`` 1501 Specify bandwidth throttling limits in bytes per second, either 1502 for all request types or for reads or writes only. Small values 1503 can lead to timeouts or hangs inside the guest. A safe minimum 1504 for disks is 2 MB/s. 1505 1506 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1507 Specify bursts in bytes per second, either for all request types 1508 or for reads or writes only. Bursts allow the guest I/O to spike 1509 above the limit temporarily. 1510 1511 ``iops=i,iops_rd=r,iops_wr=w`` 1512 Specify request rate limits in requests per second, either for 1513 all request types or for reads or writes only. 1514 1515 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1516 Specify bursts in requests per second, either for all request 1517 types or for reads or writes only. Bursts allow the guest I/O to 1518 spike above the limit temporarily. 1519 1520 ``iops_size=is`` 1521 Let every is bytes of a request count as a new request for iops 1522 throttling purposes. Use this option to prevent guests from 1523 circumventing iops limits by sending fewer but larger requests. 1524 1525 ``group=g`` 1526 Join a throttling quota group with given name g. All drives that 1527 are members of the same group are accounted for together. Use 1528 this option to prevent guests from circumventing throttling 1529 limits by using many small disks instead of a single larger 1530 disk. 1531 1532 By default, the ``cache.writeback=on`` mode is used. It will report 1533 data writes as completed as soon as the data is present in the host 1534 page cache. This is safe as long as your guest OS makes sure to 1535 correctly flush disk caches where needed. If your guest OS does not 1536 handle volatile disk write caches correctly and your host crashes or 1537 loses power, then the guest may experience data corruption. 1538 1539 For such guests, you should consider using ``cache.writeback=off``. 1540 This means that the host page cache will be used to read and write 1541 data, but write notification will be sent to the guest only after 1542 QEMU has made sure to flush each write to the disk. Be aware that 1543 this has a major impact on performance. 1544 1545 When using the ``-snapshot`` option, unsafe caching is always used. 1546 1547 Copy-on-read avoids accessing the same backing file sectors 1548 repeatedly and is useful when the backing file is over a slow 1549 network. By default copy-on-read is off. 1550 1551 Instead of ``-cdrom`` you can use: 1552 1553 .. parsed-literal:: 1554 1555 |qemu_system| -drive file=file,index=2,media=cdrom 1556 1557 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1558 1559 .. parsed-literal:: 1560 1561 |qemu_system| -drive file=file,index=0,media=disk 1562 |qemu_system| -drive file=file,index=1,media=disk 1563 |qemu_system| -drive file=file,index=2,media=disk 1564 |qemu_system| -drive file=file,index=3,media=disk 1565 1566 You can open an image using pre-opened file descriptors from an fd 1567 set: 1568 1569 .. parsed-literal:: 1570 1571 |qemu_system| \\ 1572 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1573 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1574 -drive file=/dev/fdset/2,index=0,media=disk 1575 1576 You can connect a CDROM to the slave of ide0: 1577 1578 .. parsed-literal:: 1579 1580 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1581 1582 If you don't specify the "file=" argument, you define an empty 1583 drive: 1584 1585 .. parsed-literal:: 1586 1587 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1588 1589 Instead of ``-fda``, ``-fdb``, you can use: 1590 1591 .. parsed-literal:: 1592 1593 |qemu_system_x86| -drive file=file,index=0,if=floppy 1594 |qemu_system_x86| -drive file=file,index=1,if=floppy 1595 1596 By default, interface is "ide" and index is automatically 1597 incremented: 1598 1599 .. parsed-literal:: 1600 1601 |qemu_system_x86| -drive file=a -drive file=b" 1602 1603 is interpreted like: 1604 1605 .. parsed-literal:: 1606 1607 |qemu_system_x86| -hda a -hdb b 1608ERST 1609 1610DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1611 "-mtdblock file use 'file' as on-board Flash memory image\n", 1612 QEMU_ARCH_ALL) 1613SRST 1614``-mtdblock file`` 1615 Use file as on-board Flash memory image. 1616ERST 1617 1618DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1619 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1620SRST 1621``-sd file`` 1622 Use file as SecureDigital card image. 1623ERST 1624 1625DEF("snapshot", 0, QEMU_OPTION_snapshot, 1626 "-snapshot write to temporary files instead of disk image files\n", 1627 QEMU_ARCH_ALL) 1628SRST 1629``-snapshot`` 1630 Write to temporary files instead of disk image files. In this case, 1631 the raw disk image you use is not written back. You can however 1632 force the write back by pressing C-a s (see the :ref:`disk images` 1633 chapter in the System Emulation Users Guide). 1634ERST 1635 1636DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1637 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1638 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1639 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1640 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1641 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1642 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1643 " [[,throttling.iops-size=is]]\n" 1644 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1645 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1646 "-fsdev synth,id=id\n", 1647 QEMU_ARCH_ALL) 1648 1649SRST 1650``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1651 \ 1652``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1653 \ 1654``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1655 \ 1656``-fsdev synth,id=id[,readonly=on]`` 1657 Define a new file system device. Valid options are: 1658 1659 ``local`` 1660 Accesses to the filesystem are done by QEMU. 1661 1662 ``proxy`` 1663 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1664 1665 ``synth`` 1666 Synthetic filesystem, only used by QTests. 1667 1668 ``id=id`` 1669 Specifies identifier for this device. 1670 1671 ``path=path`` 1672 Specifies the export path for the file system device. Files 1673 under this path will be available to the 9p client on the guest. 1674 1675 ``security_model=security_model`` 1676 Specifies the security model to be used for this export path. 1677 Supported security models are "passthrough", "mapped-xattr", 1678 "mapped-file" and "none". In "passthrough" security model, files 1679 are stored using the same credentials as they are created on the 1680 guest. This requires QEMU to run as root. In "mapped-xattr" 1681 security model, some of the file attributes like uid, gid, mode 1682 bits and link target are stored as file attributes. For 1683 "mapped-file" these attributes are stored in the hidden 1684 .virtfs\_metadata directory. Directories exported by this 1685 security model cannot interact with other unix tools. "none" 1686 security model is same as passthrough except the sever won't 1687 report failures if it fails to set file attributes like 1688 ownership. Security model is mandatory only for local fsdriver. 1689 Other fsdrivers (like proxy) don't take security model as a 1690 parameter. 1691 1692 ``writeout=writeout`` 1693 This is an optional argument. The only supported value is 1694 "immediate". This means that host page cache will be used to 1695 read and write data but write notification will be sent to the 1696 guest only when the data has been reported as written by the 1697 storage subsystem. 1698 1699 ``readonly=on`` 1700 Enables exporting 9p share as a readonly mount for guests. By 1701 default read-write access is given. 1702 1703 ``socket=socket`` 1704 Enables proxy filesystem driver to use passed socket file for 1705 communicating with virtfs-proxy-helper(1). 1706 1707 ``sock_fd=sock_fd`` 1708 Enables proxy filesystem driver to use passed socket descriptor 1709 for communicating with virtfs-proxy-helper(1). Usually a helper 1710 like libvirt will create socketpair and pass one of the fds as 1711 sock\_fd. 1712 1713 ``fmode=fmode`` 1714 Specifies the default mode for newly created files on the host. 1715 Works only with security models "mapped-xattr" and 1716 "mapped-file". 1717 1718 ``dmode=dmode`` 1719 Specifies the default mode for newly created directories on the 1720 host. Works only with security models "mapped-xattr" and 1721 "mapped-file". 1722 1723 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1724 Specify bandwidth throttling limits in bytes per second, either 1725 for all request types or for reads or writes only. 1726 1727 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1728 Specify bursts in bytes per second, either for all request types 1729 or for reads or writes only. Bursts allow the guest I/O to spike 1730 above the limit temporarily. 1731 1732 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1733 Specify request rate limits in requests per second, either for 1734 all request types or for reads or writes only. 1735 1736 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1737 Specify bursts in requests per second, either for all request 1738 types or for reads or writes only. Bursts allow the guest I/O to 1739 spike above the limit temporarily. 1740 1741 ``throttling.iops-size=is`` 1742 Let every is bytes of a request count as a new request for iops 1743 throttling purposes. 1744 1745 -fsdev option is used along with -device driver "virtio-9p-...". 1746 1747``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1748 Options for virtio-9p-... driver are: 1749 1750 ``type`` 1751 Specifies the variant to be used. Supported values are "pci", 1752 "ccw" or "device", depending on the machine type. 1753 1754 ``fsdev=id`` 1755 Specifies the id value specified along with -fsdev option. 1756 1757 ``mount_tag=mount_tag`` 1758 Specifies the tag name to be used by the guest to mount this 1759 export point. 1760ERST 1761 1762DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1763 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1764 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1765 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1766 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1767 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1768 QEMU_ARCH_ALL) 1769 1770SRST 1771``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1772 \ 1773``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1774 \ 1775``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1776 \ 1777``-virtfs synth,mount_tag=mount_tag`` 1778 Define a new virtual filesystem device and expose it to the guest using 1779 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1780 directory on host is made directly accessible by guest as a pass-through 1781 file system by using the 9P network protocol for communication between 1782 host and guests, if desired even accessible, shared by several guests 1783 simultaniously. 1784 1785 Note that ``-virtfs`` is actually just a convenience shortcut for its 1786 generalized form ``-fsdev -device virtio-9p-pci``. 1787 1788 The general form of pass-through file system options are: 1789 1790 ``local`` 1791 Accesses to the filesystem are done by QEMU. 1792 1793 ``proxy`` 1794 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1795 1796 ``synth`` 1797 Synthetic filesystem, only used by QTests. 1798 1799 ``id=id`` 1800 Specifies identifier for the filesystem device 1801 1802 ``path=path`` 1803 Specifies the export path for the file system device. Files 1804 under this path will be available to the 9p client on the guest. 1805 1806 ``security_model=security_model`` 1807 Specifies the security model to be used for this export path. 1808 Supported security models are "passthrough", "mapped-xattr", 1809 "mapped-file" and "none". In "passthrough" security model, files 1810 are stored using the same credentials as they are created on the 1811 guest. This requires QEMU to run as root. In "mapped-xattr" 1812 security model, some of the file attributes like uid, gid, mode 1813 bits and link target are stored as file attributes. For 1814 "mapped-file" these attributes are stored in the hidden 1815 .virtfs\_metadata directory. Directories exported by this 1816 security model cannot interact with other unix tools. "none" 1817 security model is same as passthrough except the sever won't 1818 report failures if it fails to set file attributes like 1819 ownership. Security model is mandatory only for local fsdriver. 1820 Other fsdrivers (like proxy) don't take security model as a 1821 parameter. 1822 1823 ``writeout=writeout`` 1824 This is an optional argument. The only supported value is 1825 "immediate". This means that host page cache will be used to 1826 read and write data but write notification will be sent to the 1827 guest only when the data has been reported as written by the 1828 storage subsystem. 1829 1830 ``readonly=on`` 1831 Enables exporting 9p share as a readonly mount for guests. By 1832 default read-write access is given. 1833 1834 ``socket=socket`` 1835 Enables proxy filesystem driver to use passed socket file for 1836 communicating with virtfs-proxy-helper(1). Usually a helper like 1837 libvirt will create socketpair and pass one of the fds as 1838 sock\_fd. 1839 1840 ``sock_fd`` 1841 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1842 socket descriptor for interfacing with virtfs-proxy-helper(1). 1843 1844 ``fmode=fmode`` 1845 Specifies the default mode for newly created files on the host. 1846 Works only with security models "mapped-xattr" and 1847 "mapped-file". 1848 1849 ``dmode=dmode`` 1850 Specifies the default mode for newly created directories on the 1851 host. Works only with security models "mapped-xattr" and 1852 "mapped-file". 1853 1854 ``mount_tag=mount_tag`` 1855 Specifies the tag name to be used by the guest to mount this 1856 export point. 1857 1858 ``multidevs=multidevs`` 1859 Specifies how to deal with multiple devices being shared with a 1860 9p export. Supported behaviours are either "remap", "forbid" or 1861 "warn". The latter is the default behaviour on which virtfs 9p 1862 expects only one device to be shared with the same export, and 1863 if more than one device is shared and accessed via the same 9p 1864 export then only a warning message is logged (once) by qemu on 1865 host side. In order to avoid file ID collisions on guest you 1866 should either create a separate virtfs export for each device to 1867 be shared with guests (recommended way) or you might use "remap" 1868 instead which allows you to share multiple devices with only one 1869 export instead, which is achieved by remapping the original 1870 inode numbers from host to guest in a way that would prevent 1871 such collisions. Remapping inodes in such use cases is required 1872 because the original device IDs from host are never passed and 1873 exposed on guest. Instead all files of an export shared with 1874 virtfs always share the same device id on guest. So two files 1875 with identical inode numbers but from actually different devices 1876 on host would otherwise cause a file ID collision and hence 1877 potential misbehaviours on guest. "forbid" on the other hand 1878 assumes like "warn" that only one device is shared by the same 1879 export, however it will not only log a warning message but also 1880 deny access to additional devices on guest. Note though that 1881 "forbid" does currently not block all possible file access 1882 operations (e.g. readdir() would still return entries from other 1883 devices). 1884ERST 1885 1886DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1887 "-iscsi [user=user][,password=password]\n" 1888 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n" 1889 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1890 " [,timeout=timeout]\n" 1891 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1892 1893SRST 1894``-iscsi`` 1895 Configure iSCSI session parameters. 1896ERST 1897 1898DEFHEADING() 1899 1900DEFHEADING(USB convenience options:) 1901 1902DEF("usb", 0, QEMU_OPTION_usb, 1903 "-usb enable on-board USB host controller (if not enabled by default)\n", 1904 QEMU_ARCH_ALL) 1905SRST 1906``-usb`` 1907 Enable USB emulation on machine types with an on-board USB host 1908 controller (if not enabled by default). Note that on-board USB host 1909 controllers may not support USB 3.0. In this case 1910 ``-device qemu-xhci`` can be used instead on machines with PCI. 1911ERST 1912 1913DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1914 "-usbdevice name add the host or guest USB device 'name'\n", 1915 QEMU_ARCH_ALL) 1916SRST 1917``-usbdevice devname`` 1918 Add the USB device devname, and enable an on-board USB controller 1919 if possible and necessary (just like it can be done via 1920 ``-machine usb=on``). Note that this option is mainly intended for 1921 the user's convenience only. More fine-grained control can be 1922 achieved by selecting a USB host controller (if necessary) and the 1923 desired USB device via the ``-device`` option instead. For example, 1924 instead of using ``-usbdevice mouse`` it is possible to use 1925 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 1926 to a USB 3.0 controller instead (at least on machines that support 1927 PCI and do not have an USB controller enabled by default yet). 1928 For more details, see the chapter about 1929 :ref:`Connecting USB devices` in the System Emulation Users Guide. 1930 Possible devices for devname are: 1931 1932 ``braille`` 1933 Braille device. This will use BrlAPI to display the braille 1934 output on a real or fake device (i.e. it also creates a 1935 corresponding ``braille`` chardev automatically beside the 1936 ``usb-braille`` USB device). 1937 1938 ``keyboard`` 1939 Standard USB keyboard. Will override the PS/2 keyboard (if present). 1940 1941 ``mouse`` 1942 Virtual Mouse. This will override the PS/2 mouse emulation when 1943 activated. 1944 1945 ``tablet`` 1946 Pointer device that uses absolute coordinates (like a 1947 touchscreen). This means QEMU is able to report the mouse 1948 position without having to grab the mouse. Also overrides the 1949 PS/2 mouse emulation when activated. 1950 1951 ``wacom-tablet`` 1952 Wacom PenPartner USB tablet. 1953 1954 1955ERST 1956 1957DEFHEADING() 1958 1959DEFHEADING(Display options:) 1960 1961DEF("display", HAS_ARG, QEMU_OPTION_display, 1962#if defined(CONFIG_SPICE) 1963 "-display spice-app[,gl=on|off]\n" 1964#endif 1965#if defined(CONFIG_SDL) 1966 "-display sdl[,gl=on|core|es|off][,grab-mod=<mod>][,show-cursor=on|off]\n" 1967 " [,window-close=on|off]\n" 1968#endif 1969#if defined(CONFIG_GTK) 1970 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 1971 " [,show-tabs=on|off][,show-cursor=on|off][,window-close=on|off]\n" 1972#endif 1973#if defined(CONFIG_VNC) 1974 "-display vnc=<display>[,<optargs>]\n" 1975#endif 1976#if defined(CONFIG_CURSES) 1977 "-display curses[,charset=<encoding>]\n" 1978#endif 1979#if defined(CONFIG_COCOA) 1980 "-display cocoa[,full-grab=on|off][,swap-opt-cmd=on|off]\n" 1981#endif 1982#if defined(CONFIG_OPENGL) 1983 "-display egl-headless[,rendernode=<file>]\n" 1984#endif 1985#if defined(CONFIG_DBUS_DISPLAY) 1986 "-display dbus[,addr=<dbusaddr>]\n" 1987 " [,gl=on|core|es|off][,rendernode=<file>]\n" 1988#endif 1989#if defined(CONFIG_COCOA) 1990 "-display cocoa[,show-cursor=on|off][,left-command-key=on|off]\n" 1991#endif 1992 "-display none\n" 1993 " select display backend type\n" 1994 " The default display is equivalent to\n " 1995#if defined(CONFIG_GTK) 1996 "\"-display gtk\"\n" 1997#elif defined(CONFIG_SDL) 1998 "\"-display sdl\"\n" 1999#elif defined(CONFIG_COCOA) 2000 "\"-display cocoa\"\n" 2001#elif defined(CONFIG_VNC) 2002 "\"-vnc localhost:0,to=99,id=default\"\n" 2003#else 2004 "\"-display none\"\n" 2005#endif 2006 , QEMU_ARCH_ALL) 2007SRST 2008``-display type`` 2009 Select type of display to use. Use ``-display help`` to list the available 2010 display types. Valid values for type are 2011 2012 ``spice-app[,gl=on|off]`` 2013 Start QEMU as a Spice server and launch the default Spice client 2014 application. The Spice server will redirect the serial consoles 2015 and QEMU monitors. (Since 4.0) 2016 2017 ``dbus`` 2018 Export the display over D-Bus interfaces. (Since 7.0) 2019 2020 The connection is registered with the "org.qemu" name (and queued when 2021 already owned). 2022 2023 ``addr=<dbusaddr>`` : D-Bus bus address to connect to. 2024 2025 ``p2p=yes|no`` : Use peer-to-peer connection, accepted via QMP ``add_client``. 2026 2027 ``gl=on|off|core|es`` : Use OpenGL for rendering (the D-Bus interface 2028 will share framebuffers with DMABUF file descriptors). 2029 2030 ``sdl`` 2031 Display video output via SDL (usually in a separate graphics 2032 window; see the SDL documentation for other possibilities). 2033 Valid parameters are: 2034 2035 ``grab-mod=<mods>`` : Used to select the modifier keys for toggling 2036 the mouse grabbing in conjunction with the "g" key. ``<mods>`` can be 2037 either ``lshift-lctrl-lalt`` or ``rctrl``. 2038 2039 ``gl=on|off|core|es`` : Use OpenGL for displaying 2040 2041 ``show-cursor=on|off`` : Force showing the mouse cursor 2042 2043 ``window-close=on|off`` : Allow to quit qemu with window close button 2044 2045 ``gtk`` 2046 Display video output in a GTK window. This interface provides 2047 drop-down menus and other UI elements to configure and control 2048 the VM during runtime. Valid parameters are: 2049 2050 ``full-screen=on|off`` : Start in fullscreen mode 2051 2052 ``gl=on|off`` : Use OpenGL for displaying 2053 2054 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 2055 2056 ``show-tabs=on|off`` : Display the tab bar for switching between the 2057 various graphical interfaces (e.g. VGA and 2058 virtual console character devices) by default. 2059 2060 ``show-cursor=on|off`` : Force showing the mouse cursor 2061 2062 ``window-close=on|off`` : Allow to quit qemu with window close button 2063 2064 ``curses[,charset=<encoding>]`` 2065 Display video output via curses. For graphics device models 2066 which support a text mode, QEMU can display this output using a 2067 curses/ncurses interface. Nothing is displayed when the graphics 2068 device is in graphical mode or if the graphics device does not 2069 support a text mode. Generally only the VGA device models 2070 support text mode. The font charset used by the guest can be 2071 specified with the ``charset`` option, for example 2072 ``charset=CP850`` for IBM CP850 encoding. The default is 2073 ``CP437``. 2074 2075 ``cocoa`` 2076 Display video output in a Cocoa window. Mac only. This interface 2077 provides drop-down menus and other UI elements to configure and 2078 control the VM during runtime. Valid parameters are: 2079 2080 ``show-cursor=on|off`` : Force showing the mouse cursor 2081 2082 ``left-command-key=on|off`` : Disable forwarding left command key to host 2083 2084 ``egl-headless[,rendernode=<file>]`` 2085 Offload all OpenGL operations to a local DRI device. For any 2086 graphical display, this display needs to be paired with either 2087 VNC or SPICE displays. 2088 2089 ``vnc=<display>`` 2090 Start a VNC server on display <display> 2091 2092 ``none`` 2093 Do not display video output. The guest will still see an 2094 emulated graphics card, but its output will not be displayed to 2095 the QEMU user. This option differs from the -nographic option in 2096 that it only affects what is done with video output; -nographic 2097 also changes the destination of the serial and parallel port 2098 data. 2099ERST 2100 2101DEF("nographic", 0, QEMU_OPTION_nographic, 2102 "-nographic disable graphical output and redirect serial I/Os to console\n", 2103 QEMU_ARCH_ALL) 2104SRST 2105``-nographic`` 2106 Normally, if QEMU is compiled with graphical window support, it 2107 displays output such as guest graphics, guest console, and the QEMU 2108 monitor in a window. With this option, you can totally disable 2109 graphical output so that QEMU is a simple command line application. 2110 The emulated serial port is redirected on the console and muxed with 2111 the monitor (unless redirected elsewhere explicitly). Therefore, you 2112 can still use QEMU to debug a Linux kernel with a serial console. 2113 Use C-a h for help on switching between the console and monitor. 2114ERST 2115 2116#ifdef CONFIG_SPICE 2117DEF("spice", HAS_ARG, QEMU_OPTION_spice, 2118 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 2119 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 2120 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 2121 " [,x509-dh-key-file=<file>][,addr=addr]\n" 2122 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 2123 " [,tls-ciphers=<list>]\n" 2124 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 2125 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 2126 " [,sasl=on|off][,disable-ticketing=on|off]\n" 2127 " [,password=<string>][,password-secret=<secret-id>]\n" 2128 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 2129 " [,jpeg-wan-compression=[auto|never|always]]\n" 2130 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 2131 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 2132 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 2133 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 2134 " [,gl=[on|off]][,rendernode=<file>]\n" 2135 " enable spice\n" 2136 " at least one of {port, tls-port} is mandatory\n", 2137 QEMU_ARCH_ALL) 2138#endif 2139SRST 2140``-spice option[,option[,...]]`` 2141 Enable the spice remote desktop protocol. Valid options are 2142 2143 ``port=<nr>`` 2144 Set the TCP port spice is listening on for plaintext channels. 2145 2146 ``addr=<addr>`` 2147 Set the IP address spice is listening on. Default is any 2148 address. 2149 2150 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 2151 Force using the specified IP version. 2152 2153 ``password=<string>`` 2154 Set the password you need to authenticate. 2155 2156 This option is deprecated and insecure because it leaves the 2157 password visible in the process listing. Use ``password-secret`` 2158 instead. 2159 2160 ``password-secret=<secret-id>`` 2161 Set the ID of the ``secret`` object containing the password 2162 you need to authenticate. 2163 2164 ``sasl=on|off`` 2165 Require that the client use SASL to authenticate with the spice. 2166 The exact choice of authentication method used is controlled 2167 from the system / user's SASL configuration file for the 'qemu' 2168 service. This is typically found in /etc/sasl2/qemu.conf. If 2169 running QEMU as an unprivileged user, an environment variable 2170 SASL\_CONF\_PATH can be used to make it search alternate 2171 locations for the service config. While some SASL auth methods 2172 can also provide data encryption (eg GSSAPI), it is recommended 2173 that SASL always be combined with the 'tls' and 'x509' settings 2174 to enable use of SSL and server certificates. This ensures a 2175 data encryption preventing compromise of authentication 2176 credentials. 2177 2178 ``disable-ticketing=on|off`` 2179 Allow client connects without authentication. 2180 2181 ``disable-copy-paste=on|off`` 2182 Disable copy paste between the client and the guest. 2183 2184 ``disable-agent-file-xfer=on|off`` 2185 Disable spice-vdagent based file-xfer between the client and the 2186 guest. 2187 2188 ``tls-port=<nr>`` 2189 Set the TCP port spice is listening on for encrypted channels. 2190 2191 ``x509-dir=<dir>`` 2192 Set the x509 file directory. Expects same filenames as -vnc 2193 $display,x509=$dir 2194 2195 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2196 The x509 file names can also be configured individually. 2197 2198 ``tls-ciphers=<list>`` 2199 Specify which ciphers to use. 2200 2201 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2202 Force specific channel to be used with or without TLS 2203 encryption. The options can be specified multiple times to 2204 configure multiple channels. The special name "default" can be 2205 used to set the default mode. For channels which are not 2206 explicitly forced into one mode the spice client is allowed to 2207 pick tls/plaintext as he pleases. 2208 2209 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2210 Configure image compression (lossless). Default is auto\_glz. 2211 2212 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2213 Configure wan image compression (lossy for slow links). Default 2214 is auto. 2215 2216 ``streaming-video=[off|all|filter]`` 2217 Configure video stream detection. Default is off. 2218 2219 ``agent-mouse=[on|off]`` 2220 Enable/disable passing mouse events via vdagent. Default is on. 2221 2222 ``playback-compression=[on|off]`` 2223 Enable/disable audio stream compression (using celt 0.5.1). 2224 Default is on. 2225 2226 ``seamless-migration=[on|off]`` 2227 Enable/disable spice seamless migration. Default is off. 2228 2229 ``gl=[on|off]`` 2230 Enable/disable OpenGL context. Default is off. 2231 2232 ``rendernode=<file>`` 2233 DRM render node for OpenGL rendering. If not specified, it will 2234 pick the first available. (Since 2.9) 2235ERST 2236 2237DEF("portrait", 0, QEMU_OPTION_portrait, 2238 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2239 QEMU_ARCH_ALL) 2240SRST 2241``-portrait`` 2242 Rotate graphical output 90 deg left (only PXA LCD). 2243ERST 2244 2245DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2246 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2247 QEMU_ARCH_ALL) 2248SRST 2249``-rotate deg`` 2250 Rotate graphical output some deg left (only PXA LCD). 2251ERST 2252 2253DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2254 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2255 " select video card type\n", QEMU_ARCH_ALL) 2256SRST 2257``-vga type`` 2258 Select type of VGA card to emulate. Valid values for type are 2259 2260 ``cirrus`` 2261 Cirrus Logic GD5446 Video card. All Windows versions starting 2262 from Windows 95 should recognize and use this graphic card. For 2263 optimal performances, use 16 bit color depth in the guest and 2264 the host OS. (This card was the default before QEMU 2.2) 2265 2266 ``std`` 2267 Standard VGA card with Bochs VBE extensions. If your guest OS 2268 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2269 you want to use high resolution modes (>= 1280x1024x16) then you 2270 should use this option. (This card is the default since QEMU 2271 2.2) 2272 2273 ``vmware`` 2274 VMWare SVGA-II compatible adapter. Use it if you have 2275 sufficiently recent XFree86/XOrg server or Windows guest with a 2276 driver for this card. 2277 2278 ``qxl`` 2279 QXL paravirtual graphic card. It is VGA compatible (including 2280 VESA 2.0 VBE support). Works best with qxl guest drivers 2281 installed though. Recommended choice when using the spice 2282 protocol. 2283 2284 ``tcx`` 2285 (sun4m only) Sun TCX framebuffer. This is the default 2286 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2287 colour depths at a fixed resolution of 1024x768. 2288 2289 ``cg3`` 2290 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2291 framebuffer for sun4m machines available in both 1024x768 2292 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2293 wishing to run older Solaris versions. 2294 2295 ``virtio`` 2296 Virtio VGA card. 2297 2298 ``none`` 2299 Disable VGA card. 2300ERST 2301 2302DEF("full-screen", 0, QEMU_OPTION_full_screen, 2303 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2304SRST 2305``-full-screen`` 2306 Start in full screen. 2307ERST 2308 2309DEF("g", HAS_ARG, QEMU_OPTION_g , 2310 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2311 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2312SRST 2313``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2314 Set the initial graphical resolution and depth (PPC, SPARC only). 2315 2316 For PPC the default is 800x600x32. 2317 2318 For SPARC with the TCX graphics device, the default is 1024x768x8 2319 with the option of 1024x768x24. For cgthree, the default is 2320 1024x768x8 with the option of 1152x900x8 for people who wish to use 2321 OBP. 2322ERST 2323 2324DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2325 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2326SRST 2327``-vnc display[,option[,option[,...]]]`` 2328 Normally, if QEMU is compiled with graphical window support, it 2329 displays output such as guest graphics, guest console, and the QEMU 2330 monitor in a window. With this option, you can have QEMU listen on 2331 VNC display display and redirect the VGA display over the VNC 2332 session. It is very useful to enable the usb tablet device when 2333 using this option (option ``-device usb-tablet``). When using the 2334 VNC display, you must use the ``-k`` parameter to set the keyboard 2335 layout if you are not using en-us. Valid syntax for the display is 2336 2337 ``to=L`` 2338 With this option, QEMU will try next available VNC displays, 2339 until the number L, if the origianlly defined "-vnc display" is 2340 not available, e.g. port 5900+display is already used by another 2341 application. By default, to=0. 2342 2343 ``host:d`` 2344 TCP connections will only be allowed from host on display d. By 2345 convention the TCP port is 5900+d. Optionally, host can be 2346 omitted in which case the server will accept connections from 2347 any host. 2348 2349 ``unix:path`` 2350 Connections will be allowed over UNIX domain sockets where path 2351 is the location of a unix socket to listen for connections on. 2352 2353 ``none`` 2354 VNC is initialized but not started. The monitor ``change`` 2355 command can be used to later start the VNC server. 2356 2357 Following the display value there may be one or more option flags 2358 separated by commas. Valid options are 2359 2360 ``reverse=on|off`` 2361 Connect to a listening VNC client via a "reverse" connection. 2362 The client is specified by the display. For reverse network 2363 connections (host:d,``reverse``), the d argument is a TCP port 2364 number, not a display number. 2365 2366 ``websocket=on|off`` 2367 Opens an additional TCP listening port dedicated to VNC 2368 Websocket connections. If a bare websocket option is given, the 2369 Websocket port is 5700+display. An alternative port can be 2370 specified with the syntax ``websocket``\ =port. 2371 2372 If host is specified connections will only be allowed from this 2373 host. It is possible to control the websocket listen address 2374 independently, using the syntax ``websocket``\ =host:port. 2375 2376 If no TLS credentials are provided, the websocket connection 2377 runs in unencrypted mode. If TLS credentials are provided, the 2378 websocket connection requires encrypted client connections. 2379 2380 ``password=on|off`` 2381 Require that password based authentication is used for client 2382 connections. 2383 2384 The password must be set separately using the ``set_password`` 2385 command in the :ref:`QEMU monitor`. The 2386 syntax to change your password is: 2387 ``set_password <protocol> <password>`` where <protocol> could be 2388 either "vnc" or "spice". 2389 2390 If you would like to change <protocol> password expiration, you 2391 should use ``expire_password <protocol> <expiration-time>`` 2392 where expiration time could be one of the following options: 2393 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2394 make password expire in 60 seconds, or 1335196800 to make 2395 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2396 this date and time). 2397 2398 You can also use keywords "now" or "never" for the expiration 2399 time to allow <protocol> password to expire immediately or never 2400 expire. 2401 2402 ``password-secret=<secret-id>`` 2403 Require that password based authentication is used for client 2404 connections, using the password provided by the ``secret`` 2405 object identified by ``secret-id``. 2406 2407 ``tls-creds=ID`` 2408 Provides the ID of a set of TLS credentials to use to secure the 2409 VNC server. They will apply to both the normal VNC server socket 2410 and the websocket socket (if enabled). Setting TLS credentials 2411 will cause the VNC server socket to enable the VeNCrypt auth 2412 mechanism. The credentials should have been previously created 2413 using the ``-object tls-creds`` argument. 2414 2415 ``tls-authz=ID`` 2416 Provides the ID of the QAuthZ authorization object against which 2417 the client's x509 distinguished name will validated. This object 2418 is only resolved at time of use, so can be deleted and recreated 2419 on the fly while the VNC server is active. If missing, it will 2420 default to denying access. 2421 2422 ``sasl=on|off`` 2423 Require that the client use SASL to authenticate with the VNC 2424 server. The exact choice of authentication method used is 2425 controlled from the system / user's SASL configuration file for 2426 the 'qemu' service. This is typically found in 2427 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2428 an environment variable SASL\_CONF\_PATH can be used to make it 2429 search alternate locations for the service config. While some 2430 SASL auth methods can also provide data encryption (eg GSSAPI), 2431 it is recommended that SASL always be combined with the 'tls' 2432 and 'x509' settings to enable use of SSL and server 2433 certificates. This ensures a data encryption preventing 2434 compromise of authentication credentials. See the 2435 :ref:`VNC security` section in the System Emulation Users Guide 2436 for details on using SASL authentication. 2437 2438 ``sasl-authz=ID`` 2439 Provides the ID of the QAuthZ authorization object against which 2440 the client's SASL username will validated. This object is only 2441 resolved at time of use, so can be deleted and recreated on the 2442 fly while the VNC server is active. If missing, it will default 2443 to denying access. 2444 2445 ``acl=on|off`` 2446 Legacy method for enabling authorization of clients against the 2447 x509 distinguished name and SASL username. It results in the 2448 creation of two ``authz-list`` objects with IDs of 2449 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2450 objects must be configured with the HMP ACL commands. 2451 2452 This option is deprecated and should no longer be used. The new 2453 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2454 2455 ``lossy=on|off`` 2456 Enable lossy compression methods (gradient, JPEG, ...). If this 2457 option is set, VNC client may receive lossy framebuffer updates 2458 depending on its encoding settings. Enabling this option can 2459 save a lot of bandwidth at the expense of quality. 2460 2461 ``non-adaptive=on|off`` 2462 Disable adaptive encodings. Adaptive encodings are enabled by 2463 default. An adaptive encoding will try to detect frequently 2464 updated screen regions, and send updates in these regions using 2465 a lossy encoding (like JPEG). This can be really helpful to save 2466 bandwidth when playing videos. Disabling adaptive encodings 2467 restores the original static behavior of encodings like Tight. 2468 2469 ``share=[allow-exclusive|force-shared|ignore]`` 2470 Set display sharing policy. 'allow-exclusive' allows clients to 2471 ask for exclusive access. As suggested by the rfb spec this is 2472 implemented by dropping other connections. Connecting multiple 2473 clients in parallel requires all clients asking for a shared 2474 session (vncviewer: -shared switch). This is the default. 2475 'force-shared' disables exclusive client access. Useful for 2476 shared desktop sessions, where you don't want someone forgetting 2477 specify -shared disconnect everybody else. 'ignore' completely 2478 ignores the shared flag and allows everybody connect 2479 unconditionally. Doesn't conform to the rfb spec but is 2480 traditional QEMU behavior. 2481 2482 ``key-delay-ms`` 2483 Set keyboard delay, for key down and key up events, in 2484 milliseconds. Default is 10. Keyboards are low-bandwidth 2485 devices, so this slowdown can help the device and guest to keep 2486 up and not lose events in case events are arriving in bulk. 2487 Possible causes for the latter are flaky network connections, or 2488 scripts for automated testing. 2489 2490 ``audiodev=audiodev`` 2491 Use the specified audiodev when the VNC client requests audio 2492 transmission. When not using an -audiodev argument, this option 2493 must be omitted, otherwise is must be present and specify a 2494 valid audiodev. 2495 2496 ``power-control=on|off`` 2497 Permit the remote client to issue shutdown, reboot or reset power 2498 control requests. 2499ERST 2500 2501ARCHHEADING(, QEMU_ARCH_I386) 2502 2503ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2504 2505DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2506 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2507 QEMU_ARCH_I386) 2508SRST 2509``-win2k-hack`` 2510 Use it when installing Windows 2000 to avoid a disk full bug. After 2511 Windows 2000 is installed, you no longer need this option (this 2512 option slows down the IDE transfers). 2513ERST 2514 2515DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2516 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2517 QEMU_ARCH_I386) 2518SRST 2519``-no-fd-bootchk`` 2520 Disable boot signature checking for floppy disks in BIOS. May be 2521 needed to boot from old floppy disks. 2522ERST 2523 2524DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2525 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2526SRST 2527``-no-acpi`` 2528 Disable ACPI (Advanced Configuration and Power Interface) support. 2529 Use it if your guest OS complains about ACPI problems (PC target 2530 machine only). 2531ERST 2532 2533DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2534 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2535SRST 2536``-no-hpet`` 2537 Disable HPET support. 2538ERST 2539 2540DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2541 "-acpitable [sig=str][,rev=n][,oem_id=str][,oem_table_id=str][,oem_rev=n][,asl_compiler_id=str][,asl_compiler_rev=n][,{data|file}=file1[:file2]...]\n" 2542 " ACPI table description\n", QEMU_ARCH_I386) 2543SRST 2544``-acpitable [sig=str][,rev=n][,oem_id=str][,oem_table_id=str][,oem_rev=n] [,asl_compiler_id=str][,asl_compiler_rev=n][,data=file1[:file2]...]`` 2545 Add ACPI table with specified header fields and context from 2546 specified files. For file=, take whole ACPI table from the specified 2547 files, including all ACPI headers (possible overridden by other 2548 options). For data=, only data portion of the table is used, all 2549 header information is specified in the command line. If a SLIC table 2550 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2551 fields will override the same in the RSDT and the FADT (a.k.a. 2552 FACP), in order to ensure the field matches required by the 2553 Microsoft SLIC spec and the ACPI spec. 2554ERST 2555 2556DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2557 "-smbios file=binary\n" 2558 " load SMBIOS entry from binary file\n" 2559 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2560 " [,uefi=on|off]\n" 2561 " specify SMBIOS type 0 fields\n" 2562 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2563 " [,uuid=uuid][,sku=str][,family=str]\n" 2564 " specify SMBIOS type 1 fields\n" 2565 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2566 " [,asset=str][,location=str]\n" 2567 " specify SMBIOS type 2 fields\n" 2568 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2569 " [,sku=str]\n" 2570 " specify SMBIOS type 3 fields\n" 2571 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2572 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2573 " [,processor-id=%d]\n" 2574 " specify SMBIOS type 4 fields\n" 2575 "-smbios type=11[,value=str][,path=filename]\n" 2576 " specify SMBIOS type 11 fields\n" 2577 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2578 " [,asset=str][,part=str][,speed=%d]\n" 2579 " specify SMBIOS type 17 fields\n" 2580 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2581 " specify SMBIOS type 41 fields\n", 2582 QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2583SRST 2584``-smbios file=binary`` 2585 Load SMBIOS entry from binary file. 2586 2587``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2588 Specify SMBIOS type 0 fields 2589 2590``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2591 Specify SMBIOS type 1 fields 2592 2593``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2594 Specify SMBIOS type 2 fields 2595 2596``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2597 Specify SMBIOS type 3 fields 2598 2599``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str][,processor-id=%d]`` 2600 Specify SMBIOS type 4 fields 2601 2602``-smbios type=11[,value=str][,path=filename]`` 2603 Specify SMBIOS type 11 fields 2604 2605 This argument can be repeated multiple times, and values are added in the order they are parsed. 2606 Applications intending to use OEM strings data are encouraged to use their application name as 2607 a prefix for the value string. This facilitates passing information for multiple applications 2608 concurrently. 2609 2610 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2611 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2612 2613 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2614 the SMBIOS table in the order in which they appear. 2615 2616 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2617 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2618 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2619 data set, for example, by specifying the serial ID of a block device. 2620 2621 An example passing three strings is 2622 2623 .. parsed-literal:: 2624 2625 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2626 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2627 path=/some/file/with/oemstringsdata.txt 2628 2629 In the guest OS this is visible with the ``dmidecode`` command 2630 2631 .. parsed-literal:: 2632 2633 $ dmidecode -t 11 2634 Handle 0x0E00, DMI type 11, 5 bytes 2635 OEM Strings 2636 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2637 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2638 String 3: myapp:some extra data 2639 2640 2641``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2642 Specify SMBIOS type 17 fields 2643 2644``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2645 Specify SMBIOS type 41 fields 2646 2647 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2648 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2649 position on the PCI bus. 2650 2651 Here is an example of use: 2652 2653 .. parsed-literal:: 2654 2655 -netdev user,id=internet \\ 2656 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2657 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2658 2659 In the guest OS, the device should then appear as ``eno1``: 2660 2661 ..parsed-literal:: 2662 2663 $ ip -brief l 2664 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2665 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2666 2667 Currently, the PCI device has to be attached to the root bus. 2668 2669ERST 2670 2671DEFHEADING() 2672 2673DEFHEADING(Network options:) 2674 2675DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2676#ifdef CONFIG_SLIRP 2677 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2678 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2679 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2680 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2681 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2682#ifndef _WIN32 2683 "[,smb=dir[,smbserver=addr]]\n" 2684#endif 2685 " configure a user mode network backend with ID 'str',\n" 2686 " its DHCP server and optional services\n" 2687#endif 2688#ifdef _WIN32 2689 "-netdev tap,id=str,ifname=name\n" 2690 " configure a host TAP network backend with ID 'str'\n" 2691#else 2692 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2693 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2694 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2695 " [,poll-us=n]\n" 2696 " configure a host TAP network backend with ID 'str'\n" 2697 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2698 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2699 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2700 " to deconfigure it\n" 2701 " use '[down]script=no' to disable script execution\n" 2702 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2703 " configure it\n" 2704 " use 'fd=h' to connect to an already opened TAP interface\n" 2705 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2706 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2707 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2708 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2709 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2710 " use vhost=on to enable experimental in kernel accelerator\n" 2711 " (only has effect for virtio guests which use MSIX)\n" 2712 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2713 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2714 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2715 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2716 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2717 " spent on busy polling for vhost net\n" 2718 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2719 " configure a host TAP network backend with ID 'str' that is\n" 2720 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2721 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2722#endif 2723#ifdef __linux__ 2724 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2725 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2726 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2727 " [,rxcookie=rxcookie][,offset=offset]\n" 2728 " configure a network backend with ID 'str' connected to\n" 2729 " an Ethernet over L2TPv3 pseudowire.\n" 2730 " Linux kernel 3.3+ as well as most routers can talk\n" 2731 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2732 " VM to a router and even VM to Host. It is a nearly-universal\n" 2733 " standard (RFC3931). Note - this implementation uses static\n" 2734 " pre-configured tunnels (same as the Linux kernel).\n" 2735 " use 'src=' to specify source address\n" 2736 " use 'dst=' to specify destination address\n" 2737 " use 'udp=on' to specify udp encapsulation\n" 2738 " use 'srcport=' to specify source udp port\n" 2739 " use 'dstport=' to specify destination udp port\n" 2740 " use 'ipv6=on' to force v6\n" 2741 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2742 " well as a weak security measure\n" 2743 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2744 " use 'txcookie=0x012345678' to specify a txcookie\n" 2745 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2746 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2747 " use 'pincounter=on' to work around broken counter handling in peer\n" 2748 " use 'offset=X' to add an extra offset between header and data\n" 2749#endif 2750 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2751 " configure a network backend to connect to another network\n" 2752 " using a socket connection\n" 2753 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2754 " configure a network backend to connect to a multicast maddr and port\n" 2755 " use 'localaddr=addr' to specify the host address to send packets from\n" 2756 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2757 " configure a network backend to connect to another network\n" 2758 " using an UDP tunnel\n" 2759#ifdef CONFIG_VDE 2760 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2761 " configure a network backend to connect to port 'n' of a vde switch\n" 2762 " running on host and listening for incoming connections on 'socketpath'.\n" 2763 " Use group 'groupname' and mode 'octalmode' to change default\n" 2764 " ownership and permissions for communication port.\n" 2765#endif 2766#ifdef CONFIG_NETMAP 2767 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2768 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2769 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2770 " netmap device, defaults to '/dev/netmap')\n" 2771#endif 2772#ifdef CONFIG_POSIX 2773 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2774 " configure a vhost-user network, backed by a chardev 'dev'\n" 2775#endif 2776#ifdef __linux__ 2777 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n" 2778 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2779#endif 2780#ifdef CONFIG_VMNET 2781 "-netdev vmnet-host,id=str[,isolated=on|off][,net-uuid=uuid]\n" 2782 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2783 " configure a vmnet network backend in host mode with ID 'str',\n" 2784 " isolate this interface from others with 'isolated',\n" 2785 " configure the address range and choose a subnet mask,\n" 2786 " specify network UUID 'uuid' to disable DHCP and interact with\n" 2787 " vmnet-host interfaces within this isolated network\n" 2788 "-netdev vmnet-shared,id=str[,isolated=on|off][,nat66-prefix=addr]\n" 2789 " [,start-address=addr,end-address=addr,subnet-mask=mask]\n" 2790 " configure a vmnet network backend in shared mode with ID 'str',\n" 2791 " configure the address range and choose a subnet mask,\n" 2792 " set IPv6 ULA prefix (of length 64) to use for internal network,\n" 2793 " isolate this interface from others with 'isolated'\n" 2794 "-netdev vmnet-bridged,id=str,ifname=name[,isolated=on|off]\n" 2795 " configure a vmnet network backend in bridged mode with ID 'str',\n" 2796 " use 'ifname=name' to select a physical network interface to be bridged,\n" 2797 " isolate this interface from others with 'isolated'\n" 2798#endif 2799 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2800 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2801DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2802 "-nic [tap|bridge|" 2803#ifdef CONFIG_SLIRP 2804 "user|" 2805#endif 2806#ifdef __linux__ 2807 "l2tpv3|" 2808#endif 2809#ifdef CONFIG_VDE 2810 "vde|" 2811#endif 2812#ifdef CONFIG_NETMAP 2813 "netmap|" 2814#endif 2815#ifdef CONFIG_POSIX 2816 "vhost-user|" 2817#endif 2818#ifdef CONFIG_VMNET 2819 "vmnet-host|vmnet-shared|vmnet-bridged|" 2820#endif 2821 "socket][,option][,...][mac=macaddr]\n" 2822 " initialize an on-board / default host NIC (using MAC address\n" 2823 " macaddr) and connect it to the given host network backend\n" 2824 "-nic none use it alone to have zero network devices (the default is to\n" 2825 " provided a 'user' network connection)\n", 2826 QEMU_ARCH_ALL) 2827DEF("net", HAS_ARG, QEMU_OPTION_net, 2828 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2829 " configure or create an on-board (or machine default) NIC and\n" 2830 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2831 "-net [" 2832#ifdef CONFIG_SLIRP 2833 "user|" 2834#endif 2835 "tap|" 2836 "bridge|" 2837#ifdef CONFIG_VDE 2838 "vde|" 2839#endif 2840#ifdef CONFIG_NETMAP 2841 "netmap|" 2842#endif 2843#ifdef CONFIG_VMNET 2844 "vmnet-host|vmnet-shared|vmnet-bridged|" 2845#endif 2846 "socket][,option][,option][,...]\n" 2847 " old way to initialize a host network interface\n" 2848 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2849SRST 2850``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2851 This option is a shortcut for configuring both the on-board 2852 (default) guest NIC hardware and the host network backend in one go. 2853 The host backend options are the same as with the corresponding 2854 ``-netdev`` options below. The guest NIC model can be set with 2855 ``model=modelname``. Use ``model=help`` to list the available device 2856 types. The hardware MAC address can be set with ``mac=macaddr``. 2857 2858 The following two example do exactly the same, to show how ``-nic`` 2859 can be used to shorten the command line length: 2860 2861 .. parsed-literal:: 2862 2863 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2864 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2865 2866``-nic none`` 2867 Indicate that no network devices should be configured. It is used to 2868 override the default configuration (default NIC with "user" host 2869 network backend) which is activated if no other networking options 2870 are provided. 2871 2872``-netdev user,id=id[,option][,option][,...]`` 2873 Configure user mode host network backend which requires no 2874 administrator privilege to run. Valid options are: 2875 2876 ``id=id`` 2877 Assign symbolic name for use in monitor commands. 2878 2879 ``ipv4=on|off and ipv6=on|off`` 2880 Specify that either IPv4 or IPv6 must be enabled. If neither is 2881 specified both protocols are enabled. 2882 2883 ``net=addr[/mask]`` 2884 Set IP network address the guest will see. Optionally specify 2885 the netmask, either in the form a.b.c.d or as number of valid 2886 top-most bits. Default is 10.0.2.0/24. 2887 2888 ``host=addr`` 2889 Specify the guest-visible address of the host. Default is the 2890 2nd IP in the guest network, i.e. x.x.x.2. 2891 2892 ``ipv6-net=addr[/int]`` 2893 Set IPv6 network address the guest will see (default is 2894 fec0::/64). The network prefix is given in the usual hexadecimal 2895 IPv6 address notation. The prefix size is optional, and is given 2896 as the number of valid top-most bits (default is 64). 2897 2898 ``ipv6-host=addr`` 2899 Specify the guest-visible IPv6 address of the host. Default is 2900 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2901 2902 ``restrict=on|off`` 2903 If this option is enabled, the guest will be isolated, i.e. it 2904 will not be able to contact the host and no guest IP packets 2905 will be routed over the host to the outside. This option does 2906 not affect any explicitly set forwarding rules. 2907 2908 ``hostname=name`` 2909 Specifies the client hostname reported by the built-in DHCP 2910 server. 2911 2912 ``dhcpstart=addr`` 2913 Specify the first of the 16 IPs the built-in DHCP server can 2914 assign. Default is the 15th to 31st IP in the guest network, 2915 i.e. x.x.x.15 to x.x.x.31. 2916 2917 ``dns=addr`` 2918 Specify the guest-visible address of the virtual nameserver. The 2919 address must be different from the host address. Default is the 2920 3rd IP in the guest network, i.e. x.x.x.3. 2921 2922 ``ipv6-dns=addr`` 2923 Specify the guest-visible address of the IPv6 virtual 2924 nameserver. The address must be different from the host address. 2925 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2926 2927 ``dnssearch=domain`` 2928 Provides an entry for the domain-search list sent by the 2929 built-in DHCP server. More than one domain suffix can be 2930 transmitted by specifying this option multiple times. If 2931 supported, this will cause the guest to automatically try to 2932 append the given domain suffix(es) in case a domain name can not 2933 be resolved. 2934 2935 Example: 2936 2937 .. parsed-literal:: 2938 2939 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2940 2941 ``domainname=domain`` 2942 Specifies the client domain name reported by the built-in DHCP 2943 server. 2944 2945 ``tftp=dir`` 2946 When using the user mode network stack, activate a built-in TFTP 2947 server. The files in dir will be exposed as the root of a TFTP 2948 server. The TFTP client on the guest must be configured in 2949 binary mode (use the command ``bin`` of the Unix TFTP client). 2950 2951 ``tftp-server-name=name`` 2952 In BOOTP reply, broadcast name as the "TFTP server name" 2953 (RFC2132 option 66). This can be used to advise the guest to 2954 load boot files or configurations from a different server than 2955 the host address. 2956 2957 ``bootfile=file`` 2958 When using the user mode network stack, broadcast file as the 2959 BOOTP filename. In conjunction with ``tftp``, this can be used 2960 to network boot a guest from a local directory. 2961 2962 Example (using pxelinux): 2963 2964 .. parsed-literal:: 2965 2966 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 2967 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 2968 2969 ``smb=dir[,smbserver=addr]`` 2970 When using the user mode network stack, activate a built-in SMB 2971 server so that Windows OSes can access to the host files in 2972 ``dir`` transparently. The IP address of the SMB server can be 2973 set to addr. By default the 4th IP in the guest network is used, 2974 i.e. x.x.x.4. 2975 2976 In the guest Windows OS, the line: 2977 2978 :: 2979 2980 10.0.2.4 smbserver 2981 2982 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 2983 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 2984 NT/2000). 2985 2986 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 2987 2988 Note that a SAMBA server must be installed on the host OS. 2989 2990 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 2991 Redirect incoming TCP or UDP connections to the host port 2992 hostport to the guest IP address guestaddr on guest port 2993 guestport. If guestaddr is not specified, its value is x.x.x.15 2994 (default first address given by the built-in DHCP server). By 2995 specifying hostaddr, the rule can be bound to a specific host 2996 interface. If no connection type is set, TCP is used. This 2997 option can be given multiple times. 2998 2999 For example, to redirect host X11 connection from screen 1 to 3000 guest screen 0, use the following: 3001 3002 .. parsed-literal:: 3003 3004 # on the host 3005 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 3006 # this host xterm should open in the guest X11 server 3007 xterm -display :1 3008 3009 To redirect telnet connections from host port 5555 to telnet 3010 port on the guest, use the following: 3011 3012 .. parsed-literal:: 3013 3014 # on the host 3015 |qemu_system| -nic user,hostfwd=tcp::5555-:23 3016 telnet localhost 5555 3017 3018 Then when you use on the host ``telnet localhost 5555``, you 3019 connect to the guest telnet server. 3020 3021 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 3022 Forward guest TCP connections to the IP address server on port 3023 port to the character device dev or to a program executed by 3024 cmd:command which gets spawned for each connection. This option 3025 can be given multiple times. 3026 3027 You can either use a chardev directly and have that one used 3028 throughout QEMU's lifetime, like in the following example: 3029 3030 .. parsed-literal:: 3031 3032 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 3033 # the guest accesses it 3034 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 3035 3036 Or you can execute a command on every TCP connection established 3037 by the guest, so that QEMU behaves similar to an inetd process 3038 for that virtual server: 3039 3040 .. parsed-literal:: 3041 3042 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 3043 # and connect the TCP stream to its stdin/stdout 3044 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 3045 3046``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 3047 Configure a host TAP network backend with ID id. 3048 3049 Use the network script file to configure it and the network script 3050 dfile to deconfigure it. If name is not provided, the OS 3051 automatically provides one. The default network configure script is 3052 ``/etc/qemu-ifup`` and the default network deconfigure script is 3053 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 3054 disable script execution. 3055 3056 If running QEMU as an unprivileged user, use the network helper 3057 to configure the TAP interface and attach it to the bridge. 3058 The default network helper executable is 3059 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3060 ``br0``. 3061 3062 ``fd``\ =h can be used to specify the handle of an already opened 3063 host TAP interface. 3064 3065 Examples: 3066 3067 .. parsed-literal:: 3068 3069 #launch a QEMU instance with the default network script 3070 |qemu_system| linux.img -nic tap 3071 3072 .. parsed-literal:: 3073 3074 #launch a QEMU instance with two NICs, each one connected 3075 #to a TAP device 3076 |qemu_system| linux.img \\ 3077 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 3078 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 3079 3080 .. parsed-literal:: 3081 3082 #launch a QEMU instance with the default network helper to 3083 #connect a TAP device to bridge br0 3084 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 3085 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 3086 3087``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 3088 Connect a host TAP network interface to a host bridge device. 3089 3090 Use the network helper helper to configure the TAP interface and 3091 attach it to the bridge. The default network helper executable is 3092 ``/path/to/qemu-bridge-helper`` and the default bridge device is 3093 ``br0``. 3094 3095 Examples: 3096 3097 .. parsed-literal:: 3098 3099 #launch a QEMU instance with the default network helper to 3100 #connect a TAP device to bridge br0 3101 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 3102 3103 .. parsed-literal:: 3104 3105 #launch a QEMU instance with the default network helper to 3106 #connect a TAP device to bridge qemubr0 3107 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 3108 3109``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 3110 This host network backend can be used to connect the guest's network 3111 to another QEMU virtual machine using a TCP socket connection. If 3112 ``listen`` is specified, QEMU waits for incoming connections on port 3113 (host is optional). ``connect`` is used to connect to another QEMU 3114 instance using the ``listen`` option. ``fd``\ =h specifies an 3115 already opened TCP socket. 3116 3117 Example: 3118 3119 .. parsed-literal:: 3120 3121 # launch a first QEMU instance 3122 |qemu_system| linux.img \\ 3123 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3124 -netdev socket,id=n1,listen=:1234 3125 # connect the network of this instance to the network of the first instance 3126 |qemu_system| linux.img \\ 3127 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3128 -netdev socket,id=n2,connect=127.0.0.1:1234 3129 3130``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 3131 Configure a socket host network backend to share the guest's network 3132 traffic with another QEMU virtual machines using a UDP multicast 3133 socket, effectively making a bus for every QEMU with same multicast 3134 address maddr and port. NOTES: 3135 3136 1. Several QEMU can be running on different hosts and share same bus 3137 (assuming correct multicast setup for these hosts). 3138 3139 2. mcast support is compatible with User Mode Linux (argument 3140 ``ethN=mcast``), see http://user-mode-linux.sf.net. 3141 3142 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 3143 3144 Example: 3145 3146 .. parsed-literal:: 3147 3148 # launch one QEMU instance 3149 |qemu_system| linux.img \\ 3150 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3151 -netdev socket,id=n1,mcast=230.0.0.1:1234 3152 # launch another QEMU instance on same "bus" 3153 |qemu_system| linux.img \\ 3154 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 3155 -netdev socket,id=n2,mcast=230.0.0.1:1234 3156 # launch yet another QEMU instance on same "bus" 3157 |qemu_system| linux.img \\ 3158 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 3159 -netdev socket,id=n3,mcast=230.0.0.1:1234 3160 3161 Example (User Mode Linux compat.): 3162 3163 .. parsed-literal:: 3164 3165 # launch QEMU instance (note mcast address selected is UML's default) 3166 |qemu_system| linux.img \\ 3167 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3168 -netdev socket,id=n1,mcast=239.192.168.1:1102 3169 # launch UML 3170 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 3171 3172 Example (send packets from host's 1.2.3.4): 3173 3174 .. parsed-literal:: 3175 3176 |qemu_system| linux.img \\ 3177 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 3178 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 3179 3180``-netdev l2tpv3,id=id,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport],txsession=txsession[,rxsession=rxsession][,ipv6=on|off][,udp=on|off][,cookie64][,counter][,pincounter][,txcookie=txcookie][,rxcookie=rxcookie][,offset=offset]`` 3181 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 3182 is a popular protocol to transport Ethernet (and other Layer 2) data 3183 frames between two systems. It is present in routers, firewalls and 3184 the Linux kernel (from version 3.3 onwards). 3185 3186 This transport allows a VM to communicate to another VM, router or 3187 firewall directly. 3188 3189 ``src=srcaddr`` 3190 source address (mandatory) 3191 3192 ``dst=dstaddr`` 3193 destination address (mandatory) 3194 3195 ``udp`` 3196 select udp encapsulation (default is ip). 3197 3198 ``srcport=srcport`` 3199 source udp port. 3200 3201 ``dstport=dstport`` 3202 destination udp port. 3203 3204 ``ipv6`` 3205 force v6, otherwise defaults to v4. 3206 3207 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3208 Cookies are a weak form of security in the l2tpv3 specification. 3209 Their function is mostly to prevent misconfiguration. By default 3210 they are 32 bit. 3211 3212 ``cookie64`` 3213 Set cookie size to 64 bit instead of the default 32 3214 3215 ``counter=off`` 3216 Force a 'cut-down' L2TPv3 with no counter as in 3217 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3218 3219 ``pincounter=on`` 3220 Work around broken counter handling in peer. This may also help 3221 on networks which have packet reorder. 3222 3223 ``offset=offset`` 3224 Add an extra offset between header and data 3225 3226 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3227 the bridge br-lan on the remote Linux host 1.2.3.4: 3228 3229 .. parsed-literal:: 3230 3231 # Setup tunnel on linux host using raw ip as encapsulation 3232 # on 1.2.3.4 3233 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3234 encap udp udp_sport 16384 udp_dport 16384 3235 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3236 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3237 ifconfig vmtunnel0 mtu 1500 3238 ifconfig vmtunnel0 up 3239 brctl addif br-lan vmtunnel0 3240 3241 3242 # on 4.3.2.1 3243 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3244 3245 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3246 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3247 3248``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3249 Configure VDE backend to connect to PORT n of a vde switch running 3250 on host and listening for incoming connections on socketpath. Use 3251 GROUP groupname and MODE octalmode to change default ownership and 3252 permissions for communication port. This option is only available if 3253 QEMU has been compiled with vde support enabled. 3254 3255 Example: 3256 3257 .. parsed-literal:: 3258 3259 # launch vde switch 3260 vde_switch -F -sock /tmp/myswitch 3261 # launch QEMU instance 3262 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3263 3264``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3265 Establish a vhost-user netdev, backed by a chardev id. The chardev 3266 should be a unix domain socket backed one. The vhost-user uses a 3267 specifically defined protocol to pass vhost ioctl replacement 3268 messages to an application on the other end of the socket. On 3269 non-MSIX guests, the feature can be forced with vhostforce. Use 3270 'queues=n' to specify the number of queues to be created for 3271 multiqueue vhost-user. 3272 3273 Example: 3274 3275 :: 3276 3277 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3278 -numa node,memdev=mem \ 3279 -chardev socket,id=chr0,path=/path/to/socket \ 3280 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3281 -device virtio-net-pci,netdev=net0 3282 3283``-netdev vhost-vdpa,vhostdev=/path/to/dev`` 3284 Establish a vhost-vdpa netdev. 3285 3286 vDPA device is a device that uses a datapath which complies with 3287 the virtio specifications with a vendor specific control path. 3288 vDPA devices can be both physically located on the hardware or 3289 emulated by software. 3290 3291``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3292 Create a hub port on the emulated hub with ID hubid. 3293 3294 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3295 instead of a single netdev. Alternatively, you can also connect the 3296 hubport to another netdev with ID nd by using the ``netdev=nd`` 3297 option. 3298 3299``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3300 Legacy option to configure or create an on-board (or machine 3301 default) Network Interface Card(NIC) and connect it either to the 3302 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3303 If model is omitted, then the default NIC model associated with the 3304 machine type is used. Note that the default NIC model may change in 3305 future QEMU releases, so it is highly recommended to always specify 3306 a model. Optionally, the MAC address can be changed to mac, the 3307 device address set to addr (PCI cards only), and a name can be 3308 assigned for use in monitor commands. Optionally, for PCI cards, you 3309 can specify the number v of MSI-X vectors that the card should have; 3310 this option currently only affects virtio cards; set v = 0 to 3311 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3312 created. QEMU can emulate several different models of network card. 3313 Use ``-net nic,model=help`` for a list of available devices for your 3314 target. 3315 3316``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3317 Configure a host network backend (with the options corresponding to 3318 the same ``-netdev`` option) and connect it to the emulated hub 0 3319 (the default hub). Use name to specify the name of the hub port. 3320ERST 3321 3322DEFHEADING() 3323 3324DEFHEADING(Character device options:) 3325 3326DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3327 "-chardev help\n" 3328 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3329 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]\n" 3330 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3331 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3332 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3333 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3334 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3335 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3336 " [,logfile=PATH][,logappend=on|off]\n" 3337 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3338 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3339 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3340 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3341 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3342 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3343#ifdef _WIN32 3344 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3345 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3346#else 3347 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3348 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3349#endif 3350#ifdef CONFIG_BRLAPI 3351 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3352#endif 3353#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3354 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3355 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3356 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3357#endif 3358#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3359 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3360 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3361#endif 3362#if defined(CONFIG_SPICE) 3363 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3364 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3365#endif 3366 , QEMU_ARCH_ALL 3367) 3368 3369SRST 3370The general form of a character device option is: 3371 3372``-chardev backend,id=id[,mux=on|off][,options]`` 3373 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3374 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3375 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``, 3376 ``spicevmc``, ``spiceport``. The specific backend will determine the 3377 applicable options. 3378 3379 Use ``-chardev help`` to print all available chardev backend types. 3380 3381 All devices must have an id, which can be any string up to 127 3382 characters long. It is used to uniquely identify this device in 3383 other command line directives. 3384 3385 A character device may be used in multiplexing mode by multiple 3386 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3387 a "1:N" device, and here the "1" end is your specified chardev 3388 backend, and the "N" end is the various parts of QEMU that can talk 3389 to a chardev. If you create a chardev with ``id=myid`` and 3390 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3391 and you can then configure multiple front ends to use that chardev 3392 ID for their input/output. Up to four different front ends can be 3393 connected to a single multiplexed chardev. (Without multiplexing 3394 enabled, a chardev can only be used by a single front end.) For 3395 instance you could use this to allow a single stdio chardev to be 3396 used by two serial ports and the QEMU monitor: 3397 3398 :: 3399 3400 -chardev stdio,mux=on,id=char0 \ 3401 -mon chardev=char0,mode=readline \ 3402 -serial chardev:char0 \ 3403 -serial chardev:char0 3404 3405 You can have more than one multiplexer in a system configuration; 3406 for instance you could have a TCP port multiplexed between UART 0 3407 and UART 1, and stdio multiplexed between the QEMU monitor and a 3408 parallel port: 3409 3410 :: 3411 3412 -chardev stdio,mux=on,id=char0 \ 3413 -mon chardev=char0,mode=readline \ 3414 -parallel chardev:char0 \ 3415 -chardev tcp,...,mux=on,id=char1 \ 3416 -serial chardev:char1 \ 3417 -serial chardev:char1 3418 3419 When you're using a multiplexed character device, some escape 3420 sequences are interpreted in the input. See the chapter about 3421 :ref:`keys in the character backend multiplexer` in the 3422 System Emulation Users Guide for more details. 3423 3424 Note that some other command line options may implicitly create 3425 multiplexed character backends; for instance ``-serial mon:stdio`` 3426 creates a multiplexed stdio backend connected to the serial port and 3427 the QEMU monitor, and ``-nographic`` also multiplexes the console 3428 and the monitor to stdio. 3429 3430 There is currently no support for multiplexing in the other 3431 direction (where a single QEMU front end takes input and output from 3432 multiple chardevs). 3433 3434 Every backend supports the ``logfile`` option, which supplies the 3435 path to a file to record all data transmitted via the backend. The 3436 ``logappend`` option controls whether the log file will be truncated 3437 or appended to when opened. 3438 3439The available backends are: 3440 3441``-chardev null,id=id`` 3442 A void device. This device will not emit any data, and will drop any 3443 data it receives. The null backend does not take any options. 3444 3445``-chardev socket,id=id[,TCP options or unix options][,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,tls-creds=id][,tls-authz=id]`` 3446 Create a two-way stream socket, which can be either a TCP or a unix 3447 socket. A unix socket will be created if ``path`` is specified. 3448 Behaviour is undefined if TCP options are specified for a unix 3449 socket. 3450 3451 ``server=on|off`` specifies that the socket shall be a listening socket. 3452 3453 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3454 to connect to a listening socket. 3455 3456 ``telnet=on|off`` specifies that traffic on the socket should interpret 3457 telnet escape sequences. 3458 3459 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3460 communication. 3461 3462 ``reconnect`` sets the timeout for reconnecting on non-server 3463 sockets when the remote end goes away. qemu will delay this many 3464 seconds and then attempt to reconnect. Zero disables reconnecting, 3465 and is the default. 3466 3467 ``tls-creds`` requests enablement of the TLS protocol for 3468 encryption, and specifies the id of the TLS credentials to use for 3469 the handshake. The credentials must be previously created with the 3470 ``-object tls-creds`` argument. 3471 3472 ``tls-auth`` provides the ID of the QAuthZ authorization object 3473 against which the client's x509 distinguished name will be 3474 validated. This object is only resolved at time of use, so can be 3475 deleted and recreated on the fly while the chardev server is active. 3476 If missing, it will default to denying access. 3477 3478 TCP and unix socket options are given below: 3479 3480 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3481 ``host`` for a listening socket specifies the local address to 3482 be bound. For a connecting socket species the remote host to 3483 connect to. ``host`` is optional for listening sockets. If not 3484 specified it defaults to ``0.0.0.0``. 3485 3486 ``port`` for a listening socket specifies the local port to be 3487 bound. For a connecting socket specifies the port on the remote 3488 host to connect to. ``port`` can be given as either a port 3489 number or a service name. ``port`` is required. 3490 3491 ``to`` is only relevant to listening sockets. If it is 3492 specified, and ``port`` cannot be bound, QEMU will attempt to 3493 bind to subsequent ports up to and including ``to`` until it 3494 succeeds. ``to`` must be specified as a port number. 3495 3496 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3497 or IPv6 must be used. If neither is specified the socket may 3498 use either protocol. 3499 3500 ``nodelay=on|off`` disables the Nagle algorithm. 3501 3502 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3503 ``path`` specifies the local path of the unix socket. ``path`` 3504 is required. 3505 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3506 rather than the filesystem. Optional, defaults to false. 3507 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3508 rather than the full sun_path length. Optional, defaults to true. 3509 3510``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3511 Sends all traffic from the guest to a remote host over UDP. 3512 3513 ``host`` specifies the remote host to connect to. If not specified 3514 it defaults to ``localhost``. 3515 3516 ``port`` specifies the port on the remote host to connect to. 3517 ``port`` is required. 3518 3519 ``localaddr`` specifies the local address to bind to. If not 3520 specified it defaults to ``0.0.0.0``. 3521 3522 ``localport`` specifies the local port to bind to. If not specified 3523 any available local port will be used. 3524 3525 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3526 If neither is specified the device may use either protocol. 3527 3528``-chardev msmouse,id=id`` 3529 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3530 does not take any options. 3531 3532``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3533 Connect to a QEMU text console. ``vc`` may optionally be given a 3534 specific size. 3535 3536 ``width`` and ``height`` specify the width and height respectively 3537 of the console, in pixels. 3538 3539 ``cols`` and ``rows`` specify that the console be sized to fit a 3540 text console with the given dimensions. 3541 3542``-chardev ringbuf,id=id[,size=size]`` 3543 Create a ring buffer with fixed size ``size``. size must be a power 3544 of two and defaults to ``64K``. 3545 3546``-chardev file,id=id,path=path`` 3547 Log all traffic received from the guest to a file. 3548 3549 ``path`` specifies the path of the file to be opened. This file will 3550 be created if it does not already exist, and overwritten if it does. 3551 ``path`` is required. 3552 3553``-chardev pipe,id=id,path=path`` 3554 Create a two-way connection to the guest. The behaviour differs 3555 slightly between Windows hosts and other hosts: 3556 3557 On Windows, a single duplex pipe will be created at 3558 ``\\.pipe\path``. 3559 3560 On other hosts, 2 pipes will be created called ``path.in`` and 3561 ``path.out``. Data written to ``path.in`` will be received by the 3562 guest. Data written by the guest can be read from ``path.out``. QEMU 3563 will not create these fifos, and requires them to be present. 3564 3565 ``path`` forms part of the pipe path as described above. ``path`` is 3566 required. 3567 3568``-chardev console,id=id`` 3569 Send traffic from the guest to QEMU's standard output. ``console`` 3570 does not take any options. 3571 3572 ``console`` is only available on Windows hosts. 3573 3574``-chardev serial,id=id,path=path`` 3575 Send traffic from the guest to a serial device on the host. 3576 3577 On Unix hosts serial will actually accept any tty device, not only 3578 serial lines. 3579 3580 ``path`` specifies the name of the serial device to open. 3581 3582``-chardev pty,id=id`` 3583 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3584 does not take any options. 3585 3586 ``pty`` is not available on Windows hosts. 3587 3588``-chardev stdio,id=id[,signal=on|off]`` 3589 Connect to standard input and standard output of the QEMU process. 3590 3591 ``signal`` controls if signals are enabled on the terminal, that 3592 includes exiting QEMU with the key sequence Control-c. This option 3593 is enabled by default, use ``signal=off`` to disable it. 3594 3595``-chardev braille,id=id`` 3596 Connect to a local BrlAPI server. ``braille`` does not take any 3597 options. 3598 3599``-chardev tty,id=id,path=path`` 3600 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD 3601 and DragonFlyBSD hosts. It is an alias for ``serial``. 3602 3603 ``path`` specifies the path to the tty. ``path`` is required. 3604 3605``-chardev parallel,id=id,path=path`` 3606 \ 3607``-chardev parport,id=id,path=path`` 3608 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3609 hosts. 3610 3611 Connect to a local parallel port. 3612 3613 ``path`` specifies the path to the parallel port device. ``path`` is 3614 required. 3615 3616``-chardev spicevmc,id=id,debug=debug,name=name`` 3617 ``spicevmc`` is only available when spice support is built in. 3618 3619 ``debug`` debug level for spicevmc 3620 3621 ``name`` name of spice channel to connect to 3622 3623 Connect to a spice virtual machine channel, such as vdiport. 3624 3625``-chardev spiceport,id=id,debug=debug,name=name`` 3626 ``spiceport`` is only available when spice support is built in. 3627 3628 ``debug`` debug level for spicevmc 3629 3630 ``name`` name of spice port to connect to 3631 3632 Connect to a spice port, allowing a Spice client to handle the 3633 traffic identified by a name (preferably a fqdn). 3634ERST 3635 3636DEFHEADING() 3637 3638#ifdef CONFIG_TPM 3639DEFHEADING(TPM device options:) 3640 3641DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3642 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3643 " use path to provide path to a character device; default is /dev/tpm0\n" 3644 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3645 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3646 "-tpmdev emulator,id=id,chardev=dev\n" 3647 " configure the TPM device using chardev backend\n", 3648 QEMU_ARCH_ALL) 3649SRST 3650The general form of a TPM device option is: 3651 3652``-tpmdev backend,id=id[,options]`` 3653 The specific backend type will determine the applicable options. The 3654 ``-tpmdev`` option creates the TPM backend and requires a 3655 ``-device`` option that specifies the TPM frontend interface model. 3656 3657 Use ``-tpmdev help`` to print all available TPM backend types. 3658 3659The available backends are: 3660 3661``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3662 (Linux-host only) Enable access to the host's TPM using the 3663 passthrough driver. 3664 3665 ``path`` specifies the path to the host's TPM device, i.e., on a 3666 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3667 default ``/dev/tpm0`` is used. 3668 3669 ``cancel-path`` specifies the path to the host TPM device's sysfs 3670 entry allowing for cancellation of an ongoing TPM command. 3671 ``cancel-path`` is optional and by default QEMU will search for the 3672 sysfs entry to use. 3673 3674 Some notes about using the host's TPM with the passthrough driver: 3675 3676 The TPM device accessed by the passthrough driver must not be used 3677 by any other application on the host. 3678 3679 Since the host's firmware (BIOS/UEFI) has already initialized the 3680 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3681 the TPM again and may therefore not show a TPM-specific menu that 3682 would otherwise allow the user to configure the TPM, e.g., allow the 3683 user to enable/disable or activate/deactivate the TPM. Further, if 3684 TPM ownership is released from within a VM then the host's TPM will 3685 get disabled and deactivated. To enable and activate the TPM again 3686 afterwards, the host has to be rebooted and the user is required to 3687 enter the firmware's menu to enable and activate the TPM. If the TPM 3688 is left disabled and/or deactivated most TPM commands will fail. 3689 3690 To create a passthrough TPM use the following two options: 3691 3692 :: 3693 3694 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3695 3696 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3697 ``tpmdev=tpm0`` in the device option. 3698 3699``-tpmdev emulator,id=id,chardev=dev`` 3700 (Linux-host only) Enable access to a TPM emulator using Unix domain 3701 socket based chardev backend. 3702 3703 ``chardev`` specifies the unique ID of a character device backend 3704 that provides connection to the software TPM server. 3705 3706 To create a TPM emulator backend device with chardev socket backend: 3707 3708 :: 3709 3710 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3711ERST 3712 3713DEFHEADING() 3714 3715#endif 3716 3717DEFHEADING(Boot Image or Kernel specific:) 3718SRST 3719There are broadly 4 ways you can boot a system with QEMU. 3720 3721 - specify a firmware and let it control finding a kernel 3722 - specify a firmware and pass a hint to the kernel to boot 3723 - direct kernel image boot 3724 - manually load files into the guest's address space 3725 3726The third method is useful for quickly testing kernels but as there is 3727no firmware to pass configuration information to the kernel the 3728hardware must either be probeable, the kernel built for the exact 3729configuration or passed some configuration data (e.g. a DTB blob) 3730which tells the kernel what drivers it needs. This exact details are 3731often hardware specific. 3732 3733The final method is the most generic way of loading images into the 3734guest address space and used mostly for ``bare metal`` type 3735development where the reset vectors of the processor are taken into 3736account. 3737 3738ERST 3739 3740SRST 3741 3742For x86 machines and some other architectures ``-bios`` will generally 3743do the right thing with whatever it is given. For other machines the 3744more strict ``-pflash`` option needs an image that is sized for the 3745flash device for the given machine type. 3746 3747Please see the :ref:`system-targets-ref` section of the manual for 3748more detailed documentation. 3749 3750ERST 3751 3752DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3753 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 3754SRST 3755``-bios file`` 3756 Set the filename for the BIOS. 3757ERST 3758 3759DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 3760 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 3761SRST 3762``-pflash file`` 3763 Use file as a parallel flash image. 3764ERST 3765 3766SRST 3767 3768The kernel options were designed to work with Linux kernels although 3769other things (like hypervisors) can be packaged up as a kernel 3770executable image. The exact format of a executable image is usually 3771architecture specific. 3772 3773The way in which the kernel is started (what address it is loaded at, 3774what if any information is passed to it via CPU registers, the state 3775of the hardware when it is started, and so on) is also architecture 3776specific. Typically it follows the specification laid down by the 3777Linux kernel for how kernels for that architecture must be started. 3778 3779ERST 3780 3781DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3782 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3783SRST 3784``-kernel bzImage`` 3785 Use bzImage as kernel image. The kernel can be either a Linux kernel 3786 or in multiboot format. 3787ERST 3788 3789DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3790 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3791SRST 3792``-append cmdline`` 3793 Use cmdline as kernel command line 3794ERST 3795 3796DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3797 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3798SRST 3799``-initrd file`` 3800 Use file as initial ram disk. 3801 3802``-initrd "file1 arg=foo,file2"`` 3803 This syntax is only available with multiboot. 3804 3805 Use file1 and file2 as modules and pass arg=foo as parameter to the 3806 first module. 3807ERST 3808 3809DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3810 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3811SRST 3812``-dtb file`` 3813 Use file as a device tree binary (dtb) image and pass it to the 3814 kernel on boot. 3815ERST 3816 3817SRST 3818 3819Finally you can also manually load images directly into the address 3820space of the guest. This is most useful for developers who already 3821know the layout of their guest and take care to ensure something sane 3822will happen when the reset vector executes. 3823 3824The generic loader can be invoked by using the loader device: 3825 3826``-device loader,addr=<addr>,data=<data>,data-len=<data-len>[,data-be=<data-be>][,cpu-num=<cpu-num>]`` 3827 3828there is also the guest loader which operates in a similar way but 3829tweaks the DTB so a hypervisor loaded via ``-kernel`` can find where 3830the guest image is: 3831 3832``-device guest-loader,addr=<addr>[,kernel=<path>,[bootargs=<arguments>]][,initrd=<path>]`` 3833 3834ERST 3835 3836DEFHEADING() 3837 3838DEFHEADING(Debug/Expert options:) 3839 3840DEF("compat", HAS_ARG, QEMU_OPTION_compat, 3841 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 3842 " Policy for handling deprecated management interfaces\n" 3843 "-compat [unstable-input=accept|reject|crash][,unstable-output=accept|hide]\n" 3844 " Policy for handling unstable management interfaces\n", 3845 QEMU_ARCH_ALL) 3846SRST 3847``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 3848 Set policy for handling deprecated management interfaces (experimental): 3849 3850 ``deprecated-input=accept`` (default) 3851 Accept deprecated commands and arguments 3852 ``deprecated-input=reject`` 3853 Reject deprecated commands and arguments 3854 ``deprecated-input=crash`` 3855 Crash on deprecated commands and arguments 3856 ``deprecated-output=accept`` (default) 3857 Emit deprecated command results and events 3858 ``deprecated-output=hide`` 3859 Suppress deprecated command results and events 3860 3861 Limitation: covers only syntactic aspects of QMP. 3862 3863``-compat [unstable-input=@var{input-policy}][,unstable-output=@var{output-policy}]`` 3864 Set policy for handling unstable management interfaces (experimental): 3865 3866 ``unstable-input=accept`` (default) 3867 Accept unstable commands and arguments 3868 ``unstable-input=reject`` 3869 Reject unstable commands and arguments 3870 ``unstable-input=crash`` 3871 Crash on unstable commands and arguments 3872 ``unstable-output=accept`` (default) 3873 Emit unstable command results and events 3874 ``unstable-output=hide`` 3875 Suppress unstable command results and events 3876 3877 Limitation: covers only syntactic aspects of QMP. 3878ERST 3879 3880DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3881 "-fw_cfg [name=]<name>,file=<file>\n" 3882 " add named fw_cfg entry with contents from file\n" 3883 "-fw_cfg [name=]<name>,string=<str>\n" 3884 " add named fw_cfg entry with contents from string\n", 3885 QEMU_ARCH_ALL) 3886SRST 3887``-fw_cfg [name=]name,file=file`` 3888 Add named fw\_cfg entry with contents from file file. 3889 3890``-fw_cfg [name=]name,string=str`` 3891 Add named fw\_cfg entry with contents from string str. 3892 3893 The terminating NUL character of the contents of str will not be 3894 included as part of the fw\_cfg item data. To insert contents with 3895 embedded NUL characters, you have to use the file parameter. 3896 3897 The fw\_cfg entries are passed by QEMU through to the guest. 3898 3899 Example: 3900 3901 :: 3902 3903 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3904 3905 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3906 from ./my\_blob.bin. 3907ERST 3908 3909DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3910 "-serial dev redirect the serial port to char device 'dev'\n", 3911 QEMU_ARCH_ALL) 3912SRST 3913``-serial dev`` 3914 Redirect the virtual serial port to host character device dev. The 3915 default device is ``vc`` in graphical mode and ``stdio`` in non 3916 graphical mode. 3917 3918 This option can be used several times to simulate up to 4 serial 3919 ports. 3920 3921 Use ``-serial none`` to disable all serial ports. 3922 3923 Available character devices are: 3924 3925 ``vc[:WxH]`` 3926 Virtual console. Optionally, a width and height can be given in 3927 pixel with 3928 3929 :: 3930 3931 vc:800x600 3932 3933 It is also possible to specify width or height in characters: 3934 3935 :: 3936 3937 vc:80Cx24C 3938 3939 ``pty`` 3940 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3941 3942 ``none`` 3943 No device is allocated. 3944 3945 ``null`` 3946 void device 3947 3948 ``chardev:id`` 3949 Use a named character device defined with the ``-chardev`` 3950 option. 3951 3952 ``/dev/XXX`` 3953 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 3954 port parameters are set according to the emulated ones. 3955 3956 ``/dev/parportN`` 3957 [Linux only, parallel port only] Use host parallel port N. 3958 Currently SPP and EPP parallel port features can be used. 3959 3960 ``file:filename`` 3961 Write output to filename. No character can be read. 3962 3963 ``stdio`` 3964 [Unix only] standard input/output 3965 3966 ``pipe:filename`` 3967 name pipe filename 3968 3969 ``COMn`` 3970 [Windows only] Use host serial port n 3971 3972 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 3973 This implements UDP Net Console. When remote\_host or src\_ip 3974 are not specified they default to ``0.0.0.0``. When not using a 3975 specified src\_port a random port is automatically chosen. 3976 3977 If you just want a simple readonly console you can use 3978 ``netcat`` or ``nc``, by starting QEMU with: 3979 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 3980 QEMU writes something to that port it will appear in the 3981 netconsole session. 3982 3983 If you plan to send characters back via netconsole or you want 3984 to stop and start QEMU a lot of times, you should have QEMU use 3985 the same source port each time by using something like ``-serial 3986 udp::4555@:4556`` to QEMU. Another approach is to use a patched 3987 version of netcat which can listen to a TCP port and send and 3988 receive characters via udp. If you have a patched version of 3989 netcat which activates telnet remote echo and single char 3990 transfer, then you can use the following options to set up a 3991 netcat redirector to allow telnet on port 5555 to access the 3992 QEMU port. 3993 3994 ``QEMU Options:`` 3995 -serial udp::4555@:4556 3996 3997 ``netcat options:`` 3998 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 3999 4000 ``telnet options:`` 4001 localhost 5555 4002 4003 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 4004 The TCP Net Console has two modes of operation. It can send the 4005 serial I/O to a location or wait for a connection from a 4006 location. By default the TCP Net Console is sent to host at the 4007 port. If you use the ``server=on`` option QEMU will wait for a client 4008 socket application to connect to the port before continuing, 4009 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 4010 option disables the Nagle buffering algorithm. The ``reconnect=on`` 4011 option only applies if ``server=no`` is set, if the connection goes 4012 down it will attempt to reconnect at the given interval. If host 4013 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 4014 time is accepted. You can use ``telnet=on`` to connect to the 4015 corresponding character device. 4016 4017 ``Example to send tcp console to 192.168.0.2 port 4444`` 4018 -serial tcp:192.168.0.2:4444 4019 4020 ``Example to listen and wait on port 4444 for connection`` 4021 -serial tcp::4444,server=on 4022 4023 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 4024 -serial tcp:192.168.0.100:4444,server=on,wait=off 4025 4026 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 4027 The telnet protocol is used instead of raw tcp sockets. The 4028 options work the same as if you had specified ``-serial tcp``. 4029 The difference is that the port acts like a telnet server or 4030 client using telnet option negotiation. This will also allow you 4031 to send the MAGIC\_SYSRQ sequence if you use a telnet that 4032 supports sending the break sequence. Typically in unix telnet 4033 you do it with Control-] and then type "send break" followed by 4034 pressing the enter key. 4035 4036 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 4037 The WebSocket protocol is used instead of raw tcp socket. The 4038 port acts as a WebSocket server. Client mode is not supported. 4039 4040 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 4041 A unix domain socket is used instead of a tcp socket. The option 4042 works the same as if you had specified ``-serial tcp`` except 4043 the unix domain socket path is used for connections. 4044 4045 ``mon:dev_string`` 4046 This is a special option to allow the monitor to be multiplexed 4047 onto another serial port. The monitor is accessed with key 4048 sequence of Control-a and then pressing c. dev\_string should be 4049 any one of the serial devices specified above. An example to 4050 multiplex the monitor onto a telnet server listening on port 4051 4444 would be: 4052 4053 ``-serial mon:telnet::4444,server=on,wait=off`` 4054 4055 When the monitor is multiplexed to stdio in this way, Ctrl+C 4056 will not terminate QEMU any more but will be passed to the guest 4057 instead. 4058 4059 ``braille`` 4060 Braille device. This will use BrlAPI to display the braille 4061 output on a real or fake device. 4062 4063 ``msmouse`` 4064 Three button serial mouse. Configure the guest to use Microsoft 4065 protocol. 4066ERST 4067 4068DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 4069 "-parallel dev redirect the parallel port to char device 'dev'\n", 4070 QEMU_ARCH_ALL) 4071SRST 4072``-parallel dev`` 4073 Redirect the virtual parallel port to host device dev (same devices 4074 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 4075 to use hardware devices connected on the corresponding host parallel 4076 port. 4077 4078 This option can be used several times to simulate up to 3 parallel 4079 ports. 4080 4081 Use ``-parallel none`` to disable all parallel ports. 4082ERST 4083 4084DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 4085 "-monitor dev redirect the monitor to char device 'dev'\n", 4086 QEMU_ARCH_ALL) 4087SRST 4088``-monitor dev`` 4089 Redirect the monitor to host device dev (same devices as the serial 4090 port). The default device is ``vc`` in graphical mode and ``stdio`` 4091 in non graphical mode. Use ``-monitor none`` to disable the default 4092 monitor. 4093ERST 4094DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 4095 "-qmp dev like -monitor but opens in 'control' mode\n", 4096 QEMU_ARCH_ALL) 4097SRST 4098``-qmp dev`` 4099 Like -monitor but opens in 'control' mode. 4100ERST 4101DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 4102 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 4103 QEMU_ARCH_ALL) 4104SRST 4105``-qmp-pretty dev`` 4106 Like -qmp but uses pretty JSON formatting. 4107ERST 4108 4109DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 4110 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 4111SRST 4112``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 4113 Setup monitor on chardev name. ``mode=control`` configures 4114 a QMP monitor (a JSON RPC-style protocol) and it is not the 4115 same as HMP, the human monitor that has a "(qemu)" prompt. 4116 ``pretty`` is only valid when ``mode=control``, 4117 turning on JSON pretty printing to ease 4118 human reading and debugging. 4119ERST 4120 4121DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 4122 "-debugcon dev redirect the debug console to char device 'dev'\n", 4123 QEMU_ARCH_ALL) 4124SRST 4125``-debugcon dev`` 4126 Redirect the debug console to host device dev (same devices as the 4127 serial port). The debug console is an I/O port which is typically 4128 port 0xe9; writing to that I/O port sends output to this device. The 4129 default device is ``vc`` in graphical mode and ``stdio`` in non 4130 graphical mode. 4131ERST 4132 4133DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 4134 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 4135SRST 4136``-pidfile file`` 4137 Store the QEMU process PID in file. It is useful if you launch QEMU 4138 from a script. 4139ERST 4140 4141DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 4142 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 4143SRST 4144``-singlestep`` 4145 Run the emulation in single step mode. 4146ERST 4147 4148DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 4149 "--preconfig pause QEMU before machine is initialized (experimental)\n", 4150 QEMU_ARCH_ALL) 4151SRST 4152``--preconfig`` 4153 Pause QEMU for interactive configuration before the machine is 4154 created, which allows querying and configuring properties that will 4155 affect machine initialization. Use QMP command 'x-exit-preconfig' to 4156 exit the preconfig state and move to the next state (i.e. run guest 4157 if -S isn't used or pause the second time if -S is used). This 4158 option is experimental. 4159ERST 4160 4161DEF("S", 0, QEMU_OPTION_S, \ 4162 "-S freeze CPU at startup (use 'c' to start execution)\n", 4163 QEMU_ARCH_ALL) 4164SRST 4165``-S`` 4166 Do not start CPU at startup (you must type 'c' in the monitor). 4167ERST 4168 4169DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 4170 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 4171 " run qemu with overcommit hints\n" 4172 " mem-lock=on|off controls memory lock support (default: off)\n" 4173 " cpu-pm=on|off controls cpu power management (default: off)\n", 4174 QEMU_ARCH_ALL) 4175SRST 4176``-overcommit mem-lock=on|off`` 4177 \ 4178``-overcommit cpu-pm=on|off`` 4179 Run qemu with hints about host resource overcommit. The default is 4180 to assume that host overcommits all resources. 4181 4182 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 4183 (disabled by default). This works when host memory is not 4184 overcommitted and reduces the worst-case latency for guest. 4185 4186 Guest ability to manage power state of host cpus (increasing latency 4187 for other processes on the same host cpu, but decreasing latency for 4188 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 4189 works best when host CPU is not overcommitted. When used, host 4190 estimates of CPU cycle and power utilization will be incorrect, not 4191 taking into account guest idle time. 4192ERST 4193 4194DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 4195 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 4196 " the guest without waiting for gdb to connect; use -S too\n" 4197 " if you want it to not start execution.)\n", 4198 QEMU_ARCH_ALL) 4199SRST 4200``-gdb dev`` 4201 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 4202 in the System Emulation Users Guide). Note that this option does not pause QEMU 4203 execution -- if you want QEMU to not start the guest until you 4204 connect with gdb and issue a ``continue`` command, you will need to 4205 also pass the ``-S`` option to QEMU. 4206 4207 The most usual configuration is to listen on a local TCP socket:: 4208 4209 -gdb tcp::3117 4210 4211 but you can specify other backends; UDP, pseudo TTY, or even stdio 4212 are all reasonable use cases. For example, a stdio connection 4213 allows you to start QEMU from within gdb and establish the 4214 connection via a pipe: 4215 4216 .. parsed-literal:: 4217 4218 (gdb) target remote | exec |qemu_system| -gdb stdio ... 4219ERST 4220 4221DEF("s", 0, QEMU_OPTION_s, \ 4222 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 4223 QEMU_ARCH_ALL) 4224SRST 4225``-s`` 4226 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 4227 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 4228ERST 4229 4230DEF("d", HAS_ARG, QEMU_OPTION_d, \ 4231 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 4232 QEMU_ARCH_ALL) 4233SRST 4234``-d item1[,...]`` 4235 Enable logging of specified items. Use '-d help' for a list of log 4236 items. 4237ERST 4238 4239DEF("D", HAS_ARG, QEMU_OPTION_D, \ 4240 "-D logfile output log to logfile (default stderr)\n", 4241 QEMU_ARCH_ALL) 4242SRST 4243``-D logfile`` 4244 Output log in logfile instead of to stderr 4245ERST 4246 4247DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 4248 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 4249 QEMU_ARCH_ALL) 4250SRST 4251``-dfilter range1[,...]`` 4252 Filter debug output to that relevant to a range of target addresses. 4253 The filter spec can be either start+size, start-size or start..end 4254 where start end and size are the addresses and sizes required. For 4255 example: 4256 4257 :: 4258 4259 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 4260 4261 Will dump output for any code in the 0x1000 sized block starting at 4262 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 4263 another 0x1000 sized block starting at 0xffffffc00005f000. 4264ERST 4265 4266DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 4267 "-seed number seed the pseudo-random number generator\n", 4268 QEMU_ARCH_ALL) 4269SRST 4270``-seed number`` 4271 Force the guest to use a deterministic pseudo-random number 4272 generator, seeded with number. This does not affect crypto routines 4273 within the host. 4274ERST 4275 4276DEF("L", HAS_ARG, QEMU_OPTION_L, \ 4277 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 4278 QEMU_ARCH_ALL) 4279SRST 4280``-L path`` 4281 Set the directory for the BIOS, VGA BIOS and keymaps. 4282 4283 To list all the data directories, use ``-L help``. 4284ERST 4285 4286DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4287 "-enable-kvm enable KVM full virtualization support\n", 4288 QEMU_ARCH_ARM | QEMU_ARCH_I386 | QEMU_ARCH_MIPS | QEMU_ARCH_PPC | 4289 QEMU_ARCH_RISCV | QEMU_ARCH_S390X) 4290SRST 4291``-enable-kvm`` 4292 Enable KVM full virtualization support. This option is only 4293 available if KVM support is enabled when compiling. 4294ERST 4295 4296DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4297 "-xen-domid id specify xen guest domain id\n", 4298 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4299DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4300 "-xen-attach attach to existing xen domain\n" 4301 " libxl will use this when starting QEMU\n", 4302 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4303DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4304 "-xen-domid-restrict restrict set of available xen operations\n" 4305 " to specified domain id. (Does not affect\n" 4306 " xenpv machine type).\n", 4307 QEMU_ARCH_ARM | QEMU_ARCH_I386) 4308SRST 4309``-xen-domid id`` 4310 Specify xen guest domain id (XEN only). 4311 4312``-xen-attach`` 4313 Attach to existing xen domain. libxl will use this when starting 4314 QEMU (XEN only). Restrict set of available xen operations to 4315 specified domain id (XEN only). 4316ERST 4317 4318DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4319 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4320SRST 4321``-no-reboot`` 4322 Exit instead of rebooting. 4323ERST 4324 4325DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4326 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4327SRST 4328``-no-shutdown`` 4329 Don't exit QEMU on guest shutdown, but instead only stop the 4330 emulation. This allows for instance switching to monitor to commit 4331 changes to the disk image. 4332ERST 4333 4334DEF("action", HAS_ARG, QEMU_OPTION_action, 4335 "-action reboot=reset|shutdown\n" 4336 " action when guest reboots [default=reset]\n" 4337 "-action shutdown=poweroff|pause\n" 4338 " action when guest shuts down [default=poweroff]\n" 4339 "-action panic=pause|shutdown|exit-failure|none\n" 4340 " action when guest panics [default=shutdown]\n" 4341 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4342 " action when watchdog fires [default=reset]\n", 4343 QEMU_ARCH_ALL) 4344SRST 4345``-action event=action`` 4346 The action parameter serves to modify QEMU's default behavior when 4347 certain guest events occur. It provides a generic method for specifying the 4348 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4349 parameters. 4350 4351 Examples: 4352 4353 ``-action panic=none`` 4354 ``-action reboot=shutdown,shutdown=pause`` 4355 ``-watchdog i6300esb -action watchdog=pause`` 4356 4357ERST 4358 4359DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4360 "-loadvm [tag|id]\n" \ 4361 " start right away with a saved state (loadvm in monitor)\n", 4362 QEMU_ARCH_ALL) 4363SRST 4364``-loadvm file`` 4365 Start right away with a saved state (``loadvm`` in monitor) 4366ERST 4367 4368#ifndef _WIN32 4369DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4370 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4371#endif 4372SRST 4373``-daemonize`` 4374 Daemonize the QEMU process after initialization. QEMU will not 4375 detach from standard IO until it is ready to receive connections on 4376 any of its devices. This option is a useful way for external 4377 programs to launch QEMU without having to cope with initialization 4378 race conditions. 4379ERST 4380 4381DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4382 "-option-rom rom load a file, rom, into the option ROM space\n", 4383 QEMU_ARCH_ALL) 4384SRST 4385``-option-rom file`` 4386 Load the contents of file as an option ROM. This option is useful to 4387 load things like EtherBoot. 4388ERST 4389 4390DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4391 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4392 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4393 QEMU_ARCH_ALL) 4394 4395SRST 4396``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4397 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4398 the current UTC or local time, respectively. ``localtime`` is 4399 required for correct date in MS-DOS or Windows. To start at a 4400 specific point in time, provide datetime in the format 4401 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4402 4403 By default the RTC is driven by the host system time. This allows 4404 using of the RTC as accurate reference clock inside the guest, 4405 specifically if the host time is smoothly following an accurate 4406 external reference clock, e.g. via NTP. If you want to isolate the 4407 guest time from the host, you can set ``clock`` to ``rt`` instead, 4408 which provides a host monotonic clock if host support it. To even 4409 prevent the RTC from progressing during suspension, you can set 4410 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4411 recommended especially in icount mode in order to preserve 4412 determinism; however, note that in icount mode the speed of the 4413 virtual clock is variable and can in general differ from the host 4414 clock. 4415 4416 Enable ``driftfix`` (i386 targets only) if you experience time drift 4417 problems, specifically with Windows' ACPI HAL. This option will try 4418 to figure out how many timer interrupts were not processed by the 4419 Windows guest and will re-inject them. 4420ERST 4421 4422DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4423 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4424 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4425 " instruction, enable aligning the host and virtual clocks\n" \ 4426 " or disable real time cpu sleeping, and optionally enable\n" \ 4427 " record-and-replay mode\n", QEMU_ARCH_ALL) 4428SRST 4429``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4430 Enable virtual instruction counter. The virtual cpu will execute one 4431 instruction every 2^N ns of virtual time. If ``auto`` is specified 4432 then the virtual cpu speed will be automatically adjusted to keep 4433 virtual time within a few seconds of real time. 4434 4435 Note that while this option can give deterministic behavior, it does 4436 not provide cycle accurate emulation. Modern CPUs contain 4437 superscalar out of order cores with complex cache hierarchies. The 4438 number of instructions executed often has little or no correlation 4439 with actual performance. 4440 4441 When the virtual cpu is sleeping, the virtual time will advance at 4442 default speed unless ``sleep=on`` is specified. With 4443 ``sleep=on``, the virtual time will jump to the next timer 4444 deadline instantly whenever the virtual cpu goes to sleep mode and 4445 will not advance if no timer is enabled. This behavior gives 4446 deterministic execution times from the guest point of view. 4447 The default if icount is enabled is ``sleep=off``. 4448 ``sleep=on`` cannot be used together with either ``shift=auto`` 4449 or ``align=on``. 4450 4451 ``align=on`` will activate the delay algorithm which will try to 4452 synchronise the host clock and the virtual clock. The goal is to 4453 have a guest running at the real frequency imposed by the shift 4454 option. Whenever the guest clock is behind the host clock and if 4455 ``align=on`` is specified then we print a message to the user to 4456 inform about the delay. Currently this option does not work when 4457 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4458 shift values for which the guest clock runs ahead of the host clock. 4459 Typically this happens when the shift value is high (how high 4460 depends on the host machine). The default if icount is enabled 4461 is ``align=off``. 4462 4463 When the ``rr`` option is specified deterministic record/replay is 4464 enabled. The ``rrfile=`` option must also be provided to 4465 specify the path to the replay log. In record mode data is written 4466 to this file, and in replay mode it is read back. 4467 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4468 name. In record mode, a new VM snapshot with the given name is created 4469 at the start of execution recording. In replay mode this option 4470 specifies the snapshot name used to load the initial VM state. 4471ERST 4472 4473DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ 4474 "-watchdog model\n" \ 4475 " enable virtual hardware watchdog [default=none]\n", 4476 QEMU_ARCH_ALL) 4477SRST 4478``-watchdog model`` 4479 Create a virtual hardware watchdog device. Once enabled (by a guest 4480 action), the watchdog must be periodically polled by an agent inside 4481 the guest or else the guest will be restarted. Choose a model for 4482 which your guest has drivers. 4483 4484 The model is the model of hardware watchdog to emulate. Use 4485 ``-watchdog help`` to list available hardware models. Only one 4486 watchdog can be enabled for a guest. 4487 4488 The following models may be available: 4489 4490 ``ib700`` 4491 iBASE 700 is a very simple ISA watchdog with a single timer. 4492 4493 ``i6300esb`` 4494 Intel 6300ESB I/O controller hub is a much more featureful 4495 PCI-based dual-timer watchdog. 4496 4497 ``diag288`` 4498 A virtual watchdog for s390x backed by the diagnose 288 4499 hypercall (currently KVM only). 4500ERST 4501 4502DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4503 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4504 " action when watchdog fires [default=reset]\n", 4505 QEMU_ARCH_ALL) 4506SRST 4507``-watchdog-action action`` 4508 The action controls what QEMU will do when the watchdog timer 4509 expires. The default is ``reset`` (forcefully reset the guest). 4510 Other possible actions are: ``shutdown`` (attempt to gracefully 4511 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4512 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4513 guest), ``debug`` (print a debug message and continue), or ``none`` 4514 (do nothing). 4515 4516 Note that the ``shutdown`` action requires that the guest responds 4517 to ACPI signals, which it may not be able to do in the sort of 4518 situations where the watchdog would have expired, and thus 4519 ``-watchdog-action shutdown`` is not recommended for production use. 4520 4521 Examples: 4522 4523 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700`` 4524 4525ERST 4526 4527DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4528 "-echr chr set terminal escape character instead of ctrl-a\n", 4529 QEMU_ARCH_ALL) 4530SRST 4531``-echr numeric_ascii_value`` 4532 Change the escape character used for switching to the monitor when 4533 using monitor and serial sharing. The default is ``0x01`` when using 4534 the ``-nographic`` option. ``0x01`` is equal to pressing 4535 ``Control-a``. You can select a different character from the ascii 4536 control keys where 1 through 26 map to Control-a through Control-z. 4537 For instance you could use the either of the following to change the 4538 escape character to Control-t. 4539 4540 ``-echr 0x14``; \ ``-echr 20`` 4541 4542ERST 4543 4544DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4545 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4546 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4547 "-incoming unix:socketpath\n" \ 4548 " prepare for incoming migration, listen on\n" \ 4549 " specified protocol and socket address\n" \ 4550 "-incoming fd:fd\n" \ 4551 "-incoming exec:cmdline\n" \ 4552 " accept incoming migration on given file descriptor\n" \ 4553 " or from given external command\n" \ 4554 "-incoming defer\n" \ 4555 " wait for the URI to be specified via migrate_incoming\n", 4556 QEMU_ARCH_ALL) 4557SRST 4558``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4559 \ 4560``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4561 Prepare for incoming migration, listen on a given tcp port. 4562 4563``-incoming unix:socketpath`` 4564 Prepare for incoming migration, listen on a given unix socket. 4565 4566``-incoming fd:fd`` 4567 Accept incoming migration from a given filedescriptor. 4568 4569``-incoming exec:cmdline`` 4570 Accept incoming migration as an output from specified external 4571 command. 4572 4573``-incoming defer`` 4574 Wait for the URI to be specified via migrate\_incoming. The monitor 4575 can be used to change settings (such as migration parameters) prior 4576 to issuing the migrate\_incoming to allow the migration to begin. 4577ERST 4578 4579DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4580 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4581SRST 4582``-only-migratable`` 4583 Only allow migratable devices. Devices will not be allowed to enter 4584 an unmigratable state. 4585ERST 4586 4587DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4588 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4589SRST 4590``-nodefaults`` 4591 Don't create default devices. Normally, QEMU sets the default 4592 devices like serial port, parallel port, virtual console, monitor 4593 device, VGA adapter, floppy and CD-ROM drive and others. The 4594 ``-nodefaults`` option will disable all those default devices. 4595ERST 4596 4597#ifndef _WIN32 4598DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4599 "-chroot dir chroot to dir just before starting the VM\n", 4600 QEMU_ARCH_ALL) 4601#endif 4602SRST 4603``-chroot dir`` 4604 Immediately before starting guest execution, chroot to the specified 4605 directory. Especially useful in combination with -runas. 4606ERST 4607 4608#ifndef _WIN32 4609DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4610 "-runas user change to user id user just before starting the VM\n" \ 4611 " user can be numeric uid:gid instead\n", 4612 QEMU_ARCH_ALL) 4613#endif 4614SRST 4615``-runas user`` 4616 Immediately before starting guest execution, drop root privileges, 4617 switching to the specified user. 4618ERST 4619 4620DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4621 "-prom-env variable=value\n" 4622 " set OpenBIOS nvram variables\n", 4623 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4624SRST 4625``-prom-env variable=value`` 4626 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4627 4628 :: 4629 4630 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4631 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4632 4633 :: 4634 4635 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4636 -prom-env 'boot-device=hd:2,\yaboot' \ 4637 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4638ERST 4639DEF("semihosting", 0, QEMU_OPTION_semihosting, 4640 "-semihosting semihosting mode\n", 4641 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4642 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4643SRST 4644``-semihosting`` 4645 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4646 4647 Note that this allows guest direct access to the host filesystem, so 4648 should only be used with a trusted guest OS. 4649 4650 See the -semihosting-config option documentation for further 4651 information about the facilities this enables. 4652ERST 4653DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4654 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]\n" \ 4655 " semihosting configuration\n", 4656QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4657QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4658SRST 4659``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,userspace=on|off][,arg=str[,...]]`` 4660 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4661 only). 4662 4663 Note that this allows guest direct access to the host filesystem, so 4664 should only be used with a trusted guest OS. 4665 4666 On Arm this implements the standard semihosting API, version 2.0. 4667 4668 On M68K this implements the "ColdFire GDB" interface used by 4669 libgloss. 4670 4671 Xtensa semihosting provides basic file IO calls, such as 4672 open/read/write/seek/select. Tensilica baremetal libc for ISS and 4673 linux platform "sim" use this interface. 4674 4675 On RISC-V this implements the standard semihosting API, version 0.2. 4676 4677 ``target=native|gdb|auto`` 4678 Defines where the semihosting calls will be addressed, to QEMU 4679 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4680 means ``gdb`` during debug sessions and ``native`` otherwise. 4681 4682 ``chardev=str1`` 4683 Send the output to a chardev backend output for native or auto 4684 output when not in gdb 4685 4686 ``userspace=on|off`` 4687 Allows code running in guest userspace to access the semihosting 4688 interface. The default is that only privileged guest code can 4689 make semihosting calls. Note that setting ``userspace=on`` should 4690 only be used if all guest code is trusted (for example, in 4691 bare-metal test case code). 4692 4693 ``arg=str1,arg=str2,...`` 4694 Allows the user to pass input arguments, and can be used 4695 multiple times to build up a list. The old-style 4696 ``-kernel``/``-append`` method of passing a command line is 4697 still supported for backward compatibility. If both the 4698 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4699 specified, the former is passed to semihosting as it always 4700 takes precedence. 4701ERST 4702DEF("old-param", 0, QEMU_OPTION_old_param, 4703 "-old-param old param mode\n", QEMU_ARCH_ARM) 4704SRST 4705``-old-param`` 4706 Old param mode (ARM only). 4707ERST 4708 4709DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4710 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4711 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4712 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4713 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4714 " by the kernel, but typically no longer used by modern\n" \ 4715 " C library implementations.\n" \ 4716 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4717 " to elevate privileges using set*uid|gid system calls.\n" \ 4718 " The value 'children' will deny set*uid|gid system calls for\n" \ 4719 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4720 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4721 " blocking *fork and execve\n" \ 4722 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4723 QEMU_ARCH_ALL) 4724SRST 4725``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4726 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4727 filtering and 'off' will disable it. The default is 'off'. 4728 4729 ``obsolete=string`` 4730 Enable Obsolete system calls 4731 4732 ``elevateprivileges=string`` 4733 Disable set\*uid\|gid system calls 4734 4735 ``spawn=string`` 4736 Disable \*fork and execve 4737 4738 ``resourcecontrol=string`` 4739 Disable process affinity and schedular priority 4740ERST 4741 4742DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4743 "-readconfig <file>\n" 4744 " read config file\n", QEMU_ARCH_ALL) 4745SRST 4746``-readconfig file`` 4747 Read device configuration from file. This approach is useful when 4748 you want to spawn QEMU process with many command line options but 4749 you don't want to exceed the command line character limit. 4750ERST 4751 4752DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4753 "-no-user-config\n" 4754 " do not load default user-provided config files at startup\n", 4755 QEMU_ARCH_ALL) 4756SRST 4757``-no-user-config`` 4758 The ``-no-user-config`` option makes QEMU not load any of the 4759 user-provided config files on sysconfdir. 4760ERST 4761 4762DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4763 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4764 " specify tracing options\n", 4765 QEMU_ARCH_ALL) 4766SRST 4767``-trace [[enable=]pattern][,events=file][,file=file]`` 4768 .. include:: ../qemu-option-trace.rst.inc 4769 4770ERST 4771DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4772 "-plugin [file=]<file>[,<argname>=<argvalue>]\n" 4773 " load a plugin\n", 4774 QEMU_ARCH_ALL) 4775SRST 4776``-plugin file=file[,argname=argvalue]`` 4777 Load a plugin. 4778 4779 ``file=file`` 4780 Load the given plugin from a shared library file. 4781 4782 ``argname=argvalue`` 4783 Argument passed to the plugin. (Can be given multiple times.) 4784ERST 4785 4786HXCOMM Internal use 4787DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4788DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4789 4790DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4791 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4792 " control error message format\n" 4793 " timestamp=on enables timestamps (default: off)\n" 4794 " guest-name=on enables guest name prefix but only if\n" 4795 " -name guest option is set (default: off)\n", 4796 QEMU_ARCH_ALL) 4797SRST 4798``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4799 Control error message format. 4800 4801 ``timestamp=on|off`` 4802 Prefix messages with a timestamp. Default is off. 4803 4804 ``guest-name=on|off`` 4805 Prefix messages with guest name but only if -name guest option is set 4806 otherwise the option is ignored. Default is off. 4807ERST 4808 4809DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4810 "-dump-vmstate <file>\n" 4811 " Output vmstate information in JSON format to file.\n" 4812 " Use the scripts/vmstate-static-checker.py file to\n" 4813 " check for possible regressions in migration code\n" 4814 " by comparing two such vmstate dumps.\n", 4815 QEMU_ARCH_ALL) 4816SRST 4817``-dump-vmstate file`` 4818 Dump json-encoded vmstate information for current machine type to 4819 file in file 4820ERST 4821 4822DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4823 "-enable-sync-profile\n" 4824 " enable synchronization profiling\n", 4825 QEMU_ARCH_ALL) 4826SRST 4827``-enable-sync-profile`` 4828 Enable synchronization profiling. 4829ERST 4830 4831DEFHEADING() 4832 4833DEFHEADING(Generic object creation:) 4834 4835DEF("object", HAS_ARG, QEMU_OPTION_object, 4836 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4837 " create a new object of type TYPENAME setting properties\n" 4838 " in the order they are specified. Note that the 'id'\n" 4839 " property must be set. These objects are placed in the\n" 4840 " '/objects' path.\n", 4841 QEMU_ARCH_ALL) 4842SRST 4843``-object typename[,prop1=value1,...]`` 4844 Create a new object of type typename setting properties in the order 4845 they are specified. Note that the 'id' property must be set. These 4846 objects are placed in the '/objects' path. 4847 4848 ``-object memory-backend-file,id=id,size=size,mem-path=dir,share=on|off,discard-data=on|off,merge=on|off,dump=on|off,prealloc=on|off,host-nodes=host-nodes,policy=default|preferred|bind|interleave,align=align,readonly=on|off`` 4849 Creates a memory file backend object, which can be used to back 4850 the guest RAM with huge pages. 4851 4852 The ``id`` parameter is a unique ID that will be used to 4853 reference this memory region in other parameters, e.g. ``-numa``, 4854 ``-device nvdimm``, etc. 4855 4856 The ``size`` option provides the size of the memory region, and 4857 accepts common suffixes, e.g. ``500M``. 4858 4859 The ``mem-path`` provides the path to either a shared memory or 4860 huge page filesystem mount. 4861 4862 The ``share`` boolean option determines whether the memory 4863 region is marked as private to QEMU, or shared. The latter 4864 allows a co-operating external process to access the QEMU memory 4865 region. 4866 4867 The ``share`` is also required for pvrdma devices due to 4868 limitations in the RDMA API provided by Linux. 4869 4870 Setting share=on might affect the ability to configure NUMA 4871 bindings for the memory backend under some circumstances, see 4872 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4873 source tree for additional details. 4874 4875 Setting the ``discard-data`` boolean option to on indicates that 4876 file contents can be destroyed when QEMU exits, to avoid 4877 unnecessarily flushing data to the backing file. Note that 4878 ``discard-data`` is only an optimization, and QEMU might not 4879 discard file contents if it aborts unexpectedly or is terminated 4880 using SIGKILL. 4881 4882 The ``merge`` boolean option enables memory merge, also known as 4883 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4884 the pages for memory deduplication. 4885 4886 Setting the ``dump`` boolean option to off excludes the memory 4887 from core dumps. This feature is also known as MADV\_DONTDUMP. 4888 4889 The ``prealloc`` boolean option enables memory preallocation. 4890 4891 The ``host-nodes`` option binds the memory range to a list of 4892 NUMA host nodes. 4893 4894 The ``policy`` option sets the NUMA policy to one of the 4895 following values: 4896 4897 ``default`` 4898 default host policy 4899 4900 ``preferred`` 4901 prefer the given host node list for allocation 4902 4903 ``bind`` 4904 restrict memory allocation to the given host node list 4905 4906 ``interleave`` 4907 interleave memory allocations across the given host node 4908 list 4909 4910 The ``align`` option specifies the base address alignment when 4911 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4912 ``2M``. Some backend store specified by ``mem-path`` requires an 4913 alignment different than the default one used by QEMU, eg the 4914 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4915 such cases, users can specify the required alignment via this 4916 option. 4917 4918 The ``pmem`` option specifies whether the backing file specified 4919 by ``mem-path`` is in host persistent memory that can be 4920 accessed using the SNIA NVM programming model (e.g. Intel 4921 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4922 operations to guarantee the persistence of its own writes to 4923 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4924 migration). Also, we will map the backend-file with MAP\_SYNC 4925 flag, which ensures the file metadata is in sync for 4926 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4927 requires support from both the host kernel (since Linux kernel 4928 4.15) and the filesystem of ``mem-path`` mounted with DAX 4929 option. 4930 4931 The ``readonly`` option specifies whether the backing file is opened 4932 read-only or read-write (default). 4933 4934 ``-object memory-backend-ram,id=id,merge=on|off,dump=on|off,share=on|off,prealloc=on|off,size=size,host-nodes=host-nodes,policy=default|preferred|bind|interleave`` 4935 Creates a memory backend object, which can be used to back the 4936 guest RAM. Memory backend objects offer more control than the 4937 ``-m`` option that is traditionally used to define guest RAM. 4938 Please refer to ``memory-backend-file`` for a description of the 4939 options. 4940 4941 ``-object memory-backend-memfd,id=id,merge=on|off,dump=on|off,share=on|off,prealloc=on|off,size=size,host-nodes=host-nodes,policy=default|preferred|bind|interleave,seal=on|off,hugetlb=on|off,hugetlbsize=size`` 4942 Creates an anonymous memory file backend object, which allows 4943 QEMU to share the memory with an external process (e.g. when 4944 using vhost-user). The memory is allocated with memfd and 4945 optional sealing. (Linux only) 4946 4947 The ``seal`` option creates a sealed-file, that will block 4948 further resizing the memory ('on' by default). 4949 4950 The ``hugetlb`` option specify the file to be created resides in 4951 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4952 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 4953 the hugetlb page size on systems that support multiple hugetlb 4954 page sizes (it must be a power of 2 value supported by the 4955 system). 4956 4957 In some versions of Linux, the ``hugetlb`` option is 4958 incompatible with the ``seal`` option (requires at least Linux 4959 4.16). 4960 4961 Please refer to ``memory-backend-file`` for a description of the 4962 other options. 4963 4964 The ``share`` boolean option is on by default with memfd. 4965 4966 ``-object rng-builtin,id=id`` 4967 Creates a random number generator backend which obtains entropy 4968 from QEMU builtin functions. The ``id`` parameter is a unique ID 4969 that will be used to reference this entropy backend from the 4970 ``virtio-rng`` device. By default, the ``virtio-rng`` device 4971 uses this RNG backend. 4972 4973 ``-object rng-random,id=id,filename=/dev/random`` 4974 Creates a random number generator backend which obtains entropy 4975 from a device on the host. The ``id`` parameter is a unique ID 4976 that will be used to reference this entropy backend from the 4977 ``virtio-rng`` device. The ``filename`` parameter specifies 4978 which file to obtain entropy from and if omitted defaults to 4979 ``/dev/urandom``. 4980 4981 ``-object rng-egd,id=id,chardev=chardevid`` 4982 Creates a random number generator backend which obtains entropy 4983 from an external daemon running on the host. The ``id`` 4984 parameter is a unique ID that will be used to reference this 4985 entropy backend from the ``virtio-rng`` device. The ``chardev`` 4986 parameter is the unique ID of a character device backend that 4987 provides the connection to the RNG daemon. 4988 4989 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 4990 Creates a TLS anonymous credentials object, which can be used to 4991 provide TLS support on network backends. The ``id`` parameter is 4992 a unique ID which network backends will use to access the 4993 credentials. The ``endpoint`` is either ``server`` or ``client`` 4994 depending on whether the QEMU network backend that uses the 4995 credentials will be acting as a client or as a server. If 4996 ``verify-peer`` is enabled (the default) then once the handshake 4997 is completed, the peer credentials will be verified, though this 4998 is a no-op for anonymous credentials. 4999 5000 The dir parameter tells QEMU where to find the credential files. 5001 For server endpoints, this directory may contain a file 5002 dh-params.pem providing diffie-hellman parameters to use for the 5003 TLS server. If the file is missing, QEMU will generate a set of 5004 DH parameters at startup. This is a computationally expensive 5005 operation that consumes random pool entropy, so it is 5006 recommended that a persistent set of parameters be generated 5007 upfront and saved. 5008 5009 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 5010 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 5011 can be used to provide TLS support on network backends. The 5012 ``id`` parameter is a unique ID which network backends will use 5013 to access the credentials. The ``endpoint`` is either ``server`` 5014 or ``client`` depending on whether the QEMU network backend that 5015 uses the credentials will be acting as a client or as a server. 5016 For clients only, ``username`` is the username which will be 5017 sent to the server. If omitted it defaults to "qemu". 5018 5019 The dir parameter tells QEMU where to find the keys file. It is 5020 called "dir/keys.psk" and contains "username:key" pairs. This 5021 file can most easily be created using the GnuTLS ``psktool`` 5022 program. 5023 5024 For server endpoints, dir may also contain a file dh-params.pem 5025 providing diffie-hellman parameters to use for the TLS server. 5026 If the file is missing, QEMU will generate a set of DH 5027 parameters at startup. This is a computationally expensive 5028 operation that consumes random pool entropy, so it is 5029 recommended that a persistent set of parameters be generated up 5030 front and saved. 5031 5032 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 5033 Creates a TLS anonymous credentials object, which can be used to 5034 provide TLS support on network backends. The ``id`` parameter is 5035 a unique ID which network backends will use to access the 5036 credentials. The ``endpoint`` is either ``server`` or ``client`` 5037 depending on whether the QEMU network backend that uses the 5038 credentials will be acting as a client or as a server. If 5039 ``verify-peer`` is enabled (the default) then once the handshake 5040 is completed, the peer credentials will be verified. With x509 5041 certificates, this implies that the clients must be provided 5042 with valid client certificates too. 5043 5044 The dir parameter tells QEMU where to find the credential files. 5045 For server endpoints, this directory may contain a file 5046 dh-params.pem providing diffie-hellman parameters to use for the 5047 TLS server. If the file is missing, QEMU will generate a set of 5048 DH parameters at startup. This is a computationally expensive 5049 operation that consumes random pool entropy, so it is 5050 recommended that a persistent set of parameters be generated 5051 upfront and saved. 5052 5053 For x509 certificate credentials the directory will contain 5054 further files providing the x509 certificates. The certificates 5055 must be stored in PEM format, in filenames ca-cert.pem, 5056 ca-crl.pem (optional), server-cert.pem (only servers), 5057 server-key.pem (only servers), client-cert.pem (only clients), 5058 and client-key.pem (only clients). 5059 5060 For the server-key.pem and client-key.pem files which contain 5061 sensitive private keys, it is possible to use an encrypted 5062 version by providing the passwordid parameter. This provides the 5063 ID of a previously created ``secret`` object containing the 5064 password for decryption. 5065 5066 The priority parameter allows to override the global default 5067 priority used by gnutls. This can be useful if the system 5068 administrator needs to use a weaker set of crypto priorities for 5069 QEMU without potentially forcing the weakness onto all 5070 applications. Or conversely if one wants wants a stronger 5071 default for QEMU than for all other applications, they can do 5072 this through this parameter. Its format is a gnutls priority 5073 string as described at 5074 https://gnutls.org/manual/html_node/Priority-Strings.html. 5075 5076 ``-object tls-cipher-suites,id=id,priority=priority`` 5077 Creates a TLS cipher suites object, which can be used to control 5078 the TLS cipher/protocol algorithms that applications are permitted 5079 to use. 5080 5081 The ``id`` parameter is a unique ID which frontends will use to 5082 access the ordered list of permitted TLS cipher suites from the 5083 host. 5084 5085 The ``priority`` parameter allows to override the global default 5086 priority used by gnutls. This can be useful if the system 5087 administrator needs to use a weaker set of crypto priorities for 5088 QEMU without potentially forcing the weakness onto all 5089 applications. Or conversely if one wants wants a stronger 5090 default for QEMU than for all other applications, they can do 5091 this through this parameter. Its format is a gnutls priority 5092 string as described at 5093 https://gnutls.org/manual/html_node/Priority-Strings.html. 5094 5095 An example of use of this object is to control UEFI HTTPS Boot. 5096 The tls-cipher-suites object exposes the ordered list of permitted 5097 TLS cipher suites from the host side to the guest firmware, via 5098 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 5099 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 5100 guest-side TLS. 5101 5102 In the following example, the priority at which the host-side policy 5103 is retrieved is given by the ``priority`` property. 5104 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 5105 refer to /etc/crypto-policies/back-ends/gnutls.config. 5106 5107 .. parsed-literal:: 5108 5109 # |qemu_system| \\ 5110 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 5111 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 5112 5113 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 5114 Interval t can't be 0, this filter batches the packet delivery: 5115 all packets arriving in a given interval on netdev netdevid are 5116 delayed until the end of the interval. Interval is in 5117 microseconds. ``status`` is optional that indicate whether the 5118 netfilter is on (enabled) or off (disabled), the default status 5119 for netfilter will be 'on'. 5120 5121 queue all\|rx\|tx is an option that can be applied to any 5122 netfilter. 5123 5124 ``all``: the filter is attached both to the receive and the 5125 transmit queue of the netdev (default). 5126 5127 ``rx``: the filter is attached to the receive queue of the 5128 netdev, where it will receive packets sent to the netdev. 5129 5130 ``tx``: the filter is attached to the transmit queue of the 5131 netdev, where it will receive packets sent by the netdev. 5132 5133 position head\|tail\|id=<id> is an option to specify where the 5134 filter should be inserted in the filter list. It can be applied 5135 to any netfilter. 5136 5137 ``head``: the filter is inserted at the head of the filter list, 5138 before any existing filters. 5139 5140 ``tail``: the filter is inserted at the tail of the filter list, 5141 behind any existing filters (default). 5142 5143 ``id=<id>``: the filter is inserted before or behind the filter 5144 specified by <id>, see the insert option below. 5145 5146 insert behind\|before is an option to specify where to insert 5147 the new filter relative to the one specified with 5148 position=id=<id>. It can be applied to any netfilter. 5149 5150 ``before``: insert before the specified filter. 5151 5152 ``behind``: insert behind the specified filter (default). 5153 5154 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5155 filter-mirror on netdev netdevid,mirror net packet to 5156 chardevchardevid, if it has the vnet\_hdr\_support flag, 5157 filter-mirror will mirror packet with vnet\_hdr\_len. 5158 5159 ``-object filter-redirector,id=id,netdev=netdevid,indev=chardevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5160 filter-redirector on netdev netdevid,redirect filter's net 5161 packet to chardev chardevid,and redirect indev's packet to 5162 filter.if it has the vnet\_hdr\_support flag, filter-redirector 5163 will redirect packet with vnet\_hdr\_len. Create a 5164 filter-redirector we need to differ outdev id from indev id, id 5165 can not be the same. we can just use indev or outdev, but at 5166 least one of indev or outdev need to be specified. 5167 5168 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 5169 Filter-rewriter is a part of COLO project.It will rewrite tcp 5170 packet to secondary from primary to keep secondary tcp 5171 connection,and rewrite tcp packet to primary from secondary make 5172 tcp packet can be handled by client.if it has the 5173 vnet\_hdr\_support flag, we can parse packet with vnet header. 5174 5175 usage: colo secondary: -object 5176 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 5177 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 5178 filter-rewriter,id=rew0,netdev=hn0,queue=all 5179 5180 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 5181 Dump the network traffic on netdev dev to the file specified by 5182 filename. At most len bytes (64k by default) per packet are 5183 stored. The file format is libpcap, so it can be analyzed with 5184 tools such as tcpdump or Wireshark. 5185 5186 ``-object colo-compare,id=id,primary_in=chardevid,secondary_in=chardevid,outdev=chardevid,iothread=id[,vnet_hdr_support][,notify_dev=id][,compare_timeout=@var{ms}][,expired_scan_cycle=@var{ms}][,max_queue_size=@var{size}]`` 5187 Colo-compare gets packet from primary\_in chardevid and 5188 secondary\_in, then compare whether the payload of primary packet 5189 and secondary packet are the same. If same, it will output 5190 primary packet to out\_dev, else it will notify COLO-framework to do 5191 checkpoint and send primary packet to out\_dev. In order to 5192 improve efficiency, we need to put the task of comparison in 5193 another iothread. If it has the vnet\_hdr\_support flag, 5194 colo compare will send/recv packet with vnet\_hdr\_len. 5195 The compare\_timeout=@var{ms} determines the maximum time of the 5196 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 5197 is to set the period of scanning expired primary node network packets. 5198 The max\_queue\_size=@var{size} is to set the max compare queue 5199 size depend on user environment. 5200 If user want to use Xen COLO, need to add the notify\_dev to 5201 notify Xen colo-frame to do checkpoint. 5202 5203 COLO-compare must be used with the help of filter-mirror, 5204 filter-redirector and filter-rewriter. 5205 5206 :: 5207 5208 KVM COLO 5209 5210 primary: 5211 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5212 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5213 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5214 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5215 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5216 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5217 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5218 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5219 -object iothread,id=iothread1 5220 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5221 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5222 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5223 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 5224 5225 secondary: 5226 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5227 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5228 -chardev socket,id=red0,host=3.3.3.3,port=9003 5229 -chardev socket,id=red1,host=3.3.3.3,port=9004 5230 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5231 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5232 5233 5234 Xen COLO 5235 5236 primary: 5237 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 5238 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 5239 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 5240 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 5241 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 5242 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 5243 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 5244 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 5245 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 5246 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 5247 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 5248 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 5249 -object iothread,id=iothread1 5250 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 5251 5252 secondary: 5253 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 5254 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 5255 -chardev socket,id=red0,host=3.3.3.3,port=9003 5256 -chardev socket,id=red1,host=3.3.3.3,port=9004 5257 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 5258 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 5259 5260 If you want to know the detail of above command line, you can 5261 read the colo-compare git log. 5262 5263 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 5264 Creates a cryptodev backend which executes crypto opreation from 5265 the QEMU cipher APIS. The id parameter is a unique ID that will 5266 be used to reference this cryptodev backend from the 5267 ``virtio-crypto`` device. The queues parameter is optional, 5268 which specify the queue number of cryptodev backend, the default 5269 of queues is 1. 5270 5271 .. parsed-literal:: 5272 5273 # |qemu_system| \\ 5274 [...] \\ 5275 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5276 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5277 [...] 5278 5279 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5280 Creates a vhost-user cryptodev backend, backed by a chardev 5281 chardevid. The id parameter is a unique ID that will be used to 5282 reference this cryptodev backend from the ``virtio-crypto`` 5283 device. The chardev should be a unix domain socket backed one. 5284 The vhost-user uses a specifically defined protocol to pass 5285 vhost ioctl replacement messages to an application on the other 5286 end of the socket. The queues parameter is optional, which 5287 specify the queue number of cryptodev backend for multiqueue 5288 vhost-user, the default of queues is 1. 5289 5290 .. parsed-literal:: 5291 5292 # |qemu_system| \\ 5293 [...] \\ 5294 -chardev socket,id=chardev0,path=/path/to/socket \\ 5295 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5296 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5297 [...] 5298 5299 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5300 \ 5301 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5302 Defines a secret to store a password, encryption key, or some 5303 other sensitive data. The sensitive data can either be passed 5304 directly via the data parameter, or indirectly via the file 5305 parameter. Using the data parameter is insecure unless the 5306 sensitive data is encrypted. 5307 5308 The sensitive data can be provided in raw format (the default), 5309 or base64. When encoded as JSON, the raw format only supports 5310 valid UTF-8 characters, so base64 is recommended for sending 5311 binary data. QEMU will convert from which ever format is 5312 provided to the format it needs internally. eg, an RBD password 5313 can be provided in raw format, even though it will be base64 5314 encoded when passed onto the RBD sever. 5315 5316 For added protection, it is possible to encrypt the data 5317 associated with a secret using the AES-256-CBC cipher. Use of 5318 encryption is indicated by providing the keyid and iv 5319 parameters. The keyid parameter provides the ID of a previously 5320 defined secret that contains the AES-256 decryption key. This 5321 key should be 32-bytes long and be base64 encoded. The iv 5322 parameter provides the random initialization vector used for 5323 encryption of this particular secret and should be a base64 5324 encrypted string of the 16-byte IV. 5325 5326 The simplest (insecure) usage is to provide the secret inline 5327 5328 .. parsed-literal:: 5329 5330 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5331 5332 The simplest secure usage is to provide the secret via a file 5333 5334 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5335 secret,id=sec0,file=mypasswd.txt,format=raw 5336 5337 For greater security, AES-256-CBC should be used. To illustrate 5338 usage, consider the openssl command line tool which can encrypt 5339 the data. Note that when encrypting, the plaintext must be 5340 padded to the cipher block size (32 bytes) using the standard 5341 PKCS#5/6 compatible padding algorithm. 5342 5343 First a master key needs to be created in base64 encoding: 5344 5345 :: 5346 5347 # openssl rand -base64 32 > key.b64 5348 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5349 5350 Each secret to be encrypted needs to have a random 5351 initialization vector generated. These do not need to be kept 5352 secret 5353 5354 :: 5355 5356 # openssl rand -base64 16 > iv.b64 5357 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5358 5359 The secret to be defined can now be encrypted, in this case 5360 we're telling openssl to base64 encode the result, but it could 5361 be left as raw bytes if desired. 5362 5363 :: 5364 5365 # SECRET=$(printf "letmein" | 5366 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5367 5368 When launching QEMU, create a master secret pointing to 5369 ``key.b64`` and specify that to be used to decrypt the user 5370 password. Pass the contents of ``iv.b64`` to the second secret 5371 5372 .. parsed-literal:: 5373 5374 # |qemu_system| \\ 5375 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5376 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5377 data=$SECRET,iv=$(<iv.b64) 5378 5379 ``-object sev-guest,id=id,cbitpos=cbitpos,reduced-phys-bits=val,[sev-device=string,policy=policy,handle=handle,dh-cert-file=file,session-file=file,kernel-hashes=on|off]`` 5380 Create a Secure Encrypted Virtualization (SEV) guest object, 5381 which can be used to provide the guest memory encryption support 5382 on AMD processors. 5383 5384 When memory encryption is enabled, one of the physical address 5385 bit (aka the C-bit) is utilized to mark if a memory page is 5386 protected. The ``cbitpos`` is used to provide the C-bit 5387 position. The C-bit position is Host family dependent hence user 5388 must provide this value. On EPYC, the value should be 47. 5389 5390 When memory encryption is enabled, we loose certain bits in 5391 physical address space. The ``reduced-phys-bits`` is used to 5392 provide the number of bits we loose in physical address space. 5393 Similar to C-bit, the value is Host family dependent. On EPYC, 5394 the value should be 5. 5395 5396 The ``sev-device`` provides the device file to use for 5397 communicating with the SEV firmware running inside AMD Secure 5398 Processor. The default device is '/dev/sev'. If hardware 5399 supports memory encryption then /dev/sev devices are created by 5400 CCP driver. 5401 5402 The ``policy`` provides the guest policy to be enforced by the 5403 SEV firmware and restrict what configuration and operational 5404 commands can be performed on this guest by the hypervisor. The 5405 policy should be provided by the guest owner and is bound to the 5406 guest and cannot be changed throughout the lifetime of the 5407 guest. The default is 0. 5408 5409 If guest ``policy`` allows sharing the key with another SEV 5410 guest then ``handle`` can be use to provide handle of the guest 5411 from which to share the key. 5412 5413 The ``dh-cert-file`` and ``session-file`` provides the guest 5414 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5415 and session parameters are used for establishing a cryptographic 5416 session with the guest owner to negotiate keys used for 5417 attestation. The file must be encoded in base64. 5418 5419 The ``kernel-hashes`` adds the hashes of given kernel/initrd/ 5420 cmdline to a designated guest firmware page for measured Linux 5421 boot with -kernel. The default is off. (Since 6.2) 5422 5423 e.g to launch a SEV guest 5424 5425 .. parsed-literal:: 5426 5427 # |qemu_system_x86| \\ 5428 ...... \\ 5429 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\ 5430 -machine ...,memory-encryption=sev0 \\ 5431 ..... 5432 5433 ``-object authz-simple,id=id,identity=string`` 5434 Create an authorization object that will control access to 5435 network services. 5436 5437 The ``identity`` parameter is identifies the user and its format 5438 depends on the network service that authorization object is 5439 associated with. For authorizing based on TLS x509 certificates, 5440 the identity must be the x509 distinguished name. Note that care 5441 must be taken to escape any commas in the distinguished name. 5442 5443 An example authorization object to validate a x509 distinguished 5444 name would look like: 5445 5446 .. parsed-literal:: 5447 5448 # |qemu_system| \\ 5449 ... \\ 5450 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5451 ... 5452 5453 Note the use of quotes due to the x509 distinguished name 5454 containing whitespace, and escaping of ','. 5455 5456 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5457 Create an authorization object that will control access to 5458 network services. 5459 5460 The ``filename`` parameter is the fully qualified path to a file 5461 containing the access control list rules in JSON format. 5462 5463 An example set of rules that match against SASL usernames might 5464 look like: 5465 5466 :: 5467 5468 { 5469 "rules": [ 5470 { "match": "fred", "policy": "allow", "format": "exact" }, 5471 { "match": "bob", "policy": "allow", "format": "exact" }, 5472 { "match": "danb", "policy": "deny", "format": "glob" }, 5473 { "match": "dan*", "policy": "allow", "format": "exact" }, 5474 ], 5475 "policy": "deny" 5476 } 5477 5478 When checking access the object will iterate over all the rules 5479 and the first rule to match will have its ``policy`` value 5480 returned as the result. If no rules match, then the default 5481 ``policy`` value is returned. 5482 5483 The rules can either be an exact string match, or they can use 5484 the simple UNIX glob pattern matching to allow wildcards to be 5485 used. 5486 5487 If ``refresh`` is set to true the file will be monitored and 5488 automatically reloaded whenever its content changes. 5489 5490 As with the ``authz-simple`` object, the format of the identity 5491 strings being matched depends on the network service, but is 5492 usually a TLS x509 distinguished name, or a SASL username. 5493 5494 An example authorization object to validate a SASL username 5495 would look like: 5496 5497 .. parsed-literal:: 5498 5499 # |qemu_system| \\ 5500 ... \\ 5501 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5502 ... 5503 5504 ``-object authz-pam,id=id,service=string`` 5505 Create an authorization object that will control access to 5506 network services. 5507 5508 The ``service`` parameter provides the name of a PAM service to 5509 use for authorization. It requires that a file 5510 ``/etc/pam.d/service`` exist to provide the configuration for 5511 the ``account`` subsystem. 5512 5513 An example authorization object to validate a TLS x509 5514 distinguished name would look like: 5515 5516 .. parsed-literal:: 5517 5518 # |qemu_system| \\ 5519 ... \\ 5520 -object authz-pam,id=auth0,service=qemu-vnc \\ 5521 ... 5522 5523 There would then be a corresponding config file for PAM at 5524 ``/etc/pam.d/qemu-vnc`` that contains: 5525 5526 :: 5527 5528 account requisite pam_listfile.so item=user sense=allow \ 5529 file=/etc/qemu/vnc.allow 5530 5531 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5532 of x509 distingished names that are permitted access 5533 5534 :: 5535 5536 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5537 5538 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` 5539 Creates a dedicated event loop thread that devices can be 5540 assigned to. This is known as an IOThread. By default device 5541 emulation happens in vCPU threads or the main event loop thread. 5542 This can become a scalability bottleneck. IOThreads allow device 5543 emulation and I/O to run on other host CPUs. 5544 5545 The ``id`` parameter is a unique ID that will be used to 5546 reference this IOThread from ``-device ...,iothread=id``. 5547 Multiple devices can be assigned to an IOThread. Note that not 5548 all devices support an ``iothread`` parameter. 5549 5550 The ``query-iothreads`` QMP command lists IOThreads and reports 5551 their thread IDs so that the user can configure host CPU 5552 pinning/affinity. 5553 5554 IOThreads use an adaptive polling algorithm to reduce event loop 5555 latency. Instead of entering a blocking system call to monitor 5556 file descriptors and then pay the cost of being woken up when an 5557 event occurs, the polling algorithm spins waiting for events for 5558 a short time. The algorithm's default parameters are suitable 5559 for many cases but can be adjusted based on knowledge of the 5560 workload and/or host device latency. 5561 5562 The ``poll-max-ns`` parameter is the maximum number of 5563 nanoseconds to busy wait for events. Polling can be disabled by 5564 setting this value to 0. 5565 5566 The ``poll-grow`` parameter is the multiplier used to increase 5567 the polling time when the algorithm detects it is missing events 5568 due to not polling long enough. 5569 5570 The ``poll-shrink`` parameter is the divisor used to decrease 5571 the polling time when the algorithm detects it is spending too 5572 long polling without encountering events. 5573 5574 The ``aio-max-batch`` parameter is the maximum number of requests 5575 in a batch for the AIO engine, 0 means that the engine will use 5576 its default. 5577 5578 The IOThread parameters can be modified at run-time using the 5579 ``qom-set`` command (where ``iothread1`` is the IOThread's 5580 ``id``): 5581 5582 :: 5583 5584 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5585ERST 5586 5587 5588HXCOMM This is the last statement. Insert new options before this line! 5589 5590#undef DEF 5591#undef DEFHEADING 5592#undef ARCHHEADING 5593
