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 QEMU_ARCH_ALL) 41SRST 42``-machine [type=]name[,prop=value[,...]]`` 43 Select the emulated machine by name. Use ``-machine help`` to list 44 available machines. 45 46 For architectures which aim to support live migration compatibility 47 across releases, each release will introduce a new versioned machine 48 type. For example, the 2.8.0 release introduced machine types 49 "pc-i440fx-2.8" and "pc-q35-2.8" for the x86\_64/i686 architectures. 50 51 To allow live migration of guests from QEMU version 2.8.0, to QEMU 52 version 2.9.0, the 2.9.0 version must support the "pc-i440fx-2.8" 53 and "pc-q35-2.8" machines too. To allow users live migrating VMs to 54 skip multiple intermediate releases when upgrading, new releases of 55 QEMU will support machine types from many previous versions. 56 57 Supported machine properties are: 58 59 ``accel=accels1[:accels2[:...]]`` 60 This is used to enable an accelerator. Depending on the target 61 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. 62 By default, tcg is used. If there is more than one accelerator 63 specified, the next one is used if the previous one fails to 64 initialize. 65 66 ``vmport=on|off|auto`` 67 Enables emulation of VMWare IO port, for vmmouse etc. auto says 68 to select the value based on accel. For accel=xen the default is 69 off otherwise the default is on. 70 71 ``dump-guest-core=on|off`` 72 Include guest memory in a core dump. The default is on. 73 74 ``mem-merge=on|off`` 75 Enables or disables memory merge support. This feature, when 76 supported by the host, de-duplicates identical memory pages 77 among VMs instances (enabled by default). 78 79 ``aes-key-wrap=on|off`` 80 Enables or disables AES key wrapping support on s390-ccw hosts. 81 This feature controls whether AES wrapping keys will be created 82 to allow execution of AES cryptographic functions. The default 83 is on. 84 85 ``dea-key-wrap=on|off`` 86 Enables or disables DEA key wrapping support on s390-ccw hosts. 87 This feature controls whether DEA wrapping keys will be created 88 to allow execution of DEA cryptographic functions. The default 89 is on. 90 91 ``nvdimm=on|off`` 92 Enables or disables NVDIMM support. The default is off. 93 94 ``memory-encryption=`` 95 Memory encryption object to use. The default is none. 96 97 ``hmat=on|off`` 98 Enables or disables ACPI Heterogeneous Memory Attribute Table 99 (HMAT) support. The default is off. 100 101 ``memory-backend='id'`` 102 An alternative to legacy ``-mem-path`` and ``mem-prealloc`` options. 103 Allows to use a memory backend as main RAM. 104 105 For example: 106 :: 107 -object memory-backend-file,id=pc.ram,size=512M,mem-path=/hugetlbfs,prealloc=on,share=on 108 -machine memory-backend=pc.ram 109 -m 512M 110 111 Migration compatibility note: 112 a) as backend id one shall use value of 'default-ram-id', advertised by 113 machine type (available via ``query-machines`` QMP command), if migration 114 to/from old QEMU (<5.0) is expected. 115 b) for machine types 4.0 and older, user shall 116 use ``x-use-canonical-path-for-ramblock-id=off`` backend option 117 if migration to/from old QEMU (<5.0) is expected. 118 For example: 119 :: 120 -object memory-backend-ram,id=pc.ram,size=512M,x-use-canonical-path-for-ramblock-id=off 121 -machine memory-backend=pc.ram 122 -m 512M 123ERST 124 125HXCOMM Deprecated by -machine 126DEF("M", HAS_ARG, QEMU_OPTION_M, "", QEMU_ARCH_ALL) 127 128DEF("cpu", HAS_ARG, QEMU_OPTION_cpu, 129 "-cpu cpu select CPU ('-cpu help' for list)\n", QEMU_ARCH_ALL) 130SRST 131``-cpu model`` 132 Select CPU model (``-cpu help`` for list and additional feature 133 selection) 134ERST 135 136DEF("accel", HAS_ARG, QEMU_OPTION_accel, 137 "-accel [accel=]accelerator[,prop[=value][,...]]\n" 138 " select accelerator (kvm, xen, hax, hvf, nvmm, whpx or tcg; use 'help' for a list)\n" 139 " igd-passthru=on|off (enable Xen integrated Intel graphics passthrough, default=off)\n" 140 " kernel-irqchip=on|off|split controls accelerated irqchip support (default=on)\n" 141 " kvm-shadow-mem=size of KVM shadow MMU in bytes\n" 142 " split-wx=on|off (enable TCG split w^x mapping)\n" 143 " tb-size=n (TCG translation block cache size)\n" 144 " dirty-ring-size=n (KVM dirty ring GFN count, default 0)\n" 145 " thread=single|multi (enable multi-threaded TCG)\n", QEMU_ARCH_ALL) 146SRST 147``-accel name[,prop=value[,...]]`` 148 This is used to enable an accelerator. Depending on the target 149 architecture, kvm, xen, hax, hvf, nvmm, whpx or tcg can be available. By 150 default, tcg is used. If there is more than one accelerator 151 specified, the next one is used if the previous one fails to 152 initialize. 153 154 ``igd-passthru=on|off`` 155 When Xen is in use, this option controls whether Intel 156 integrated graphics devices can be passed through to the guest 157 (default=off) 158 159 ``kernel-irqchip=on|off|split`` 160 Controls KVM in-kernel irqchip support. The default is full 161 acceleration of the interrupt controllers. On x86, split irqchip 162 reduces the kernel attack surface, at a performance cost for 163 non-MSI interrupts. Disabling the in-kernel irqchip completely 164 is not recommended except for debugging purposes. 165 166 ``kvm-shadow-mem=size`` 167 Defines the size of the KVM shadow MMU. 168 169 ``split-wx=on|off`` 170 Controls the use of split w^x mapping for the TCG code generation 171 buffer. Some operating systems require this to be enabled, and in 172 such a case this will default on. On other operating systems, this 173 will default off, but one may enable this for testing or debugging. 174 175 ``tb-size=n`` 176 Controls the size (in MiB) of the TCG translation block cache. 177 178 ``thread=single|multi`` 179 Controls number of TCG threads. When the TCG is multi-threaded 180 there will be one thread per vCPU therefore taking advantage of 181 additional host cores. The default is to enable multi-threading 182 where both the back-end and front-ends support it and no 183 incompatible TCG features have been enabled (e.g. 184 icount/replay). 185 186 ``dirty-ring-size=n`` 187 When the KVM accelerator is used, it controls the size of the per-vCPU 188 dirty page ring buffer (number of entries for each vCPU). It should 189 be a value that is power of two, and it should be 1024 or bigger (but 190 still less than the maximum value that the kernel supports). 4096 191 could be a good initial value if you have no idea which is the best. 192 Set this value to 0 to disable the feature. By default, this feature 193 is disabled (dirty-ring-size=0). When enabled, KVM will instead 194 record dirty pages in a bitmap. 195 196ERST 197 198DEF("smp", HAS_ARG, QEMU_OPTION_smp, 199 "-smp [cpus=]n[,maxcpus=cpus][,cores=cores][,threads=threads][,dies=dies][,sockets=sockets]\n" 200 " set the number of CPUs to 'n' [default=1]\n" 201 " maxcpus= maximum number of total cpus, including\n" 202 " offline CPUs for hotplug, etc\n" 203 " cores= number of CPU cores on one socket (for PC, it's on one die)\n" 204 " threads= number of threads on one CPU core\n" 205 " dies= number of CPU dies on one socket (for PC only)\n" 206 " sockets= number of discrete sockets in the system\n", 207 QEMU_ARCH_ALL) 208SRST 209``-smp [cpus=]n[,cores=cores][,threads=threads][,dies=dies][,sockets=sockets][,maxcpus=maxcpus]`` 210 Simulate an SMP system with n CPUs. On the PC target, up to 255 CPUs 211 are supported. On Sparc32 target, Linux limits the number of usable 212 CPUs to 4. For the PC target, the number of cores per die, the 213 number of threads per cores, the number of dies per packages and the 214 total number of sockets can be specified. Missing values will be 215 computed. If any on the three values is given, the total number of 216 CPUs n can be omitted. maxcpus specifies the maximum number of 217 hotpluggable CPUs. 218ERST 219 220DEF("numa", HAS_ARG, QEMU_OPTION_numa, 221 "-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 222 "-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=node]\n" 223 "-numa dist,src=source,dst=destination,val=distance\n" 224 "-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]\n" 225 "-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" 226 "-numa hmat-cache,node-id=node,size=size,level=level[,associativity=none|direct|complex][,policy=none|write-back|write-through][,line=size]\n", 227 QEMU_ARCH_ALL) 228SRST 229``-numa node[,mem=size][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 230 \ 231``-numa node[,memdev=id][,cpus=firstcpu[-lastcpu]][,nodeid=node][,initiator=initiator]`` 232 \ 233``-numa dist,src=source,dst=destination,val=distance`` 234 \ 235``-numa cpu,node-id=node[,socket-id=x][,core-id=y][,thread-id=z]`` 236 \ 237``-numa hmat-lb,initiator=node,target=node,hierarchy=hierarchy,data-type=tpye[,latency=lat][,bandwidth=bw]`` 238 \ 239``-numa hmat-cache,node-id=node,size=size,level=level[,associativity=str][,policy=str][,line=size]`` 240 Define a NUMA node and assign RAM and VCPUs to it. Set the NUMA 241 distance from a source node to a destination node. Set the ACPI 242 Heterogeneous Memory Attributes for the given nodes. 243 244 Legacy VCPU assignment uses '\ ``cpus``\ ' option where firstcpu and 245 lastcpu are CPU indexes. Each '\ ``cpus``\ ' option represent a 246 contiguous range of CPU indexes (or a single VCPU if lastcpu is 247 omitted). A non-contiguous set of VCPUs can be represented by 248 providing multiple '\ ``cpus``\ ' options. If '\ ``cpus``\ ' is 249 omitted on all nodes, VCPUs are automatically split between them. 250 251 For example, the following option assigns VCPUs 0, 1, 2 and 5 to a 252 NUMA node: 253 254 :: 255 256 -numa node,cpus=0-2,cpus=5 257 258 '\ ``cpu``\ ' option is a new alternative to '\ ``cpus``\ ' option 259 which uses '\ ``socket-id|core-id|thread-id``\ ' properties to 260 assign CPU objects to a node using topology layout properties of 261 CPU. The set of properties is machine specific, and depends on used 262 machine type/'\ ``smp``\ ' options. It could be queried with 263 '\ ``hotpluggable-cpus``\ ' monitor command. '\ ``node-id``\ ' 264 property specifies node to which CPU object will be assigned, it's 265 required for node to be declared with '\ ``node``\ ' option before 266 it's used with '\ ``cpu``\ ' option. 267 268 For example: 269 270 :: 271 272 -M pc \ 273 -smp 1,sockets=2,maxcpus=2 \ 274 -numa node,nodeid=0 -numa node,nodeid=1 \ 275 -numa cpu,node-id=0,socket-id=0 -numa cpu,node-id=1,socket-id=1 276 277 Legacy '\ ``mem``\ ' assigns a given RAM amount to a node (not supported 278 for 5.1 and newer machine types). '\ ``memdev``\ ' assigns RAM from 279 a given memory backend device to a node. If '\ ``mem``\ ' and 280 '\ ``memdev``\ ' are omitted in all nodes, RAM is split equally between them. 281 282 283 '\ ``mem``\ ' and '\ ``memdev``\ ' are mutually exclusive. 284 Furthermore, if one node uses '\ ``memdev``\ ', all of them have to 285 use it. 286 287 '\ ``initiator``\ ' is an additional option that points to an 288 initiator NUMA node that has best performance (the lowest latency or 289 largest bandwidth) to this NUMA node. Note that this option can be 290 set only when the machine property 'hmat' is set to 'on'. 291 292 Following example creates a machine with 2 NUMA nodes, node 0 has 293 CPU. node 1 has only memory, and its initiator is node 0. Note that 294 because node 0 has CPU, by default the initiator of node 0 is itself 295 and must be itself. 296 297 :: 298 299 -machine hmat=on \ 300 -m 2G,slots=2,maxmem=4G \ 301 -object memory-backend-ram,size=1G,id=m0 \ 302 -object memory-backend-ram,size=1G,id=m1 \ 303 -numa node,nodeid=0,memdev=m0 \ 304 -numa node,nodeid=1,memdev=m1,initiator=0 \ 305 -smp 2,sockets=2,maxcpus=2 \ 306 -numa cpu,node-id=0,socket-id=0 \ 307 -numa cpu,node-id=0,socket-id=1 308 309 source and destination are NUMA node IDs. distance is the NUMA 310 distance from source to destination. The distance from a node to 311 itself is always 10. If any pair of nodes is given a distance, then 312 all pairs must be given distances. Although, when distances are only 313 given in one direction for each pair of nodes, then the distances in 314 the opposite directions are assumed to be the same. If, however, an 315 asymmetrical pair of distances is given for even one node pair, then 316 all node pairs must be provided distance values for both directions, 317 even when they are symmetrical. When a node is unreachable from 318 another node, set the pair's distance to 255. 319 320 Note that the -``numa`` option doesn't allocate any of the specified 321 resources, it just assigns existing resources to NUMA nodes. This 322 means that one still has to use the ``-m``, ``-smp`` options to 323 allocate RAM and VCPUs respectively. 324 325 Use '\ ``hmat-lb``\ ' to set System Locality Latency and Bandwidth 326 Information between initiator and target NUMA nodes in ACPI 327 Heterogeneous Attribute Memory Table (HMAT). Initiator NUMA node can 328 create memory requests, usually it has one or more processors. 329 Target NUMA node contains addressable memory. 330 331 In '\ ``hmat-lb``\ ' option, node are NUMA node IDs. hierarchy is 332 the memory hierarchy of the target NUMA node: if hierarchy is 333 'memory', the structure represents the memory performance; if 334 hierarchy is 'first-level\|second-level\|third-level', this 335 structure represents aggregated performance of memory side caches 336 for each domain. type of 'data-type' is type of data represented by 337 this structure instance: if 'hierarchy' is 'memory', 'data-type' is 338 'access\|read\|write' latency or 'access\|read\|write' bandwidth of 339 the target memory; if 'hierarchy' is 340 'first-level\|second-level\|third-level', 'data-type' is 341 'access\|read\|write' hit latency or 'access\|read\|write' hit 342 bandwidth of the target memory side cache. 343 344 lat is latency value in nanoseconds. bw is bandwidth value, the 345 possible value and units are NUM[M\|G\|T], mean that the bandwidth 346 value are NUM byte per second (or MB/s, GB/s or TB/s depending on 347 used suffix). Note that if latency or bandwidth value is 0, means 348 the corresponding latency or bandwidth information is not provided. 349 350 In '\ ``hmat-cache``\ ' option, node-id is the NUMA-id of the memory 351 belongs. size is the size of memory side cache in bytes. level is 352 the cache level described in this structure, note that the cache 353 level 0 should not be used with '\ ``hmat-cache``\ ' option. 354 associativity is the cache associativity, the possible value is 355 'none/direct(direct-mapped)/complex(complex cache indexing)'. policy 356 is the write policy. line is the cache Line size in bytes. 357 358 For example, the following options describe 2 NUMA nodes. Node 0 has 359 2 cpus and a ram, node 1 has only a ram. The processors in node 0 360 access memory in node 0 with access-latency 5 nanoseconds, 361 access-bandwidth is 200 MB/s; The processors in NUMA node 0 access 362 memory in NUMA node 1 with access-latency 10 nanoseconds, 363 access-bandwidth is 100 MB/s. And for memory side cache information, 364 NUMA node 0 and 1 both have 1 level memory cache, size is 10KB, 365 policy is write-back, the cache Line size is 8 bytes: 366 367 :: 368 369 -machine hmat=on \ 370 -m 2G \ 371 -object memory-backend-ram,size=1G,id=m0 \ 372 -object memory-backend-ram,size=1G,id=m1 \ 373 -smp 2 \ 374 -numa node,nodeid=0,memdev=m0 \ 375 -numa node,nodeid=1,memdev=m1,initiator=0 \ 376 -numa cpu,node-id=0,socket-id=0 \ 377 -numa cpu,node-id=0,socket-id=1 \ 378 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-latency,latency=5 \ 379 -numa hmat-lb,initiator=0,target=0,hierarchy=memory,data-type=access-bandwidth,bandwidth=200M \ 380 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-latency,latency=10 \ 381 -numa hmat-lb,initiator=0,target=1,hierarchy=memory,data-type=access-bandwidth,bandwidth=100M \ 382 -numa hmat-cache,node-id=0,size=10K,level=1,associativity=direct,policy=write-back,line=8 \ 383 -numa hmat-cache,node-id=1,size=10K,level=1,associativity=direct,policy=write-back,line=8 384ERST 385 386DEF("add-fd", HAS_ARG, QEMU_OPTION_add_fd, 387 "-add-fd fd=fd,set=set[,opaque=opaque]\n" 388 " Add 'fd' to fd 'set'\n", QEMU_ARCH_ALL) 389SRST 390``-add-fd fd=fd,set=set[,opaque=opaque]`` 391 Add a file descriptor to an fd set. Valid options are: 392 393 ``fd=fd`` 394 This option defines the file descriptor of which a duplicate is 395 added to fd set. The file descriptor cannot be stdin, stdout, or 396 stderr. 397 398 ``set=set`` 399 This option defines the ID of the fd set to add the file 400 descriptor to. 401 402 ``opaque=opaque`` 403 This option defines a free-form string that can be used to 404 describe fd. 405 406 You can open an image using pre-opened file descriptors from an fd 407 set: 408 409 .. parsed-literal:: 410 411 |qemu_system| \\ 412 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 413 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 414 -drive file=/dev/fdset/2,index=0,media=disk 415ERST 416 417DEF("set", HAS_ARG, QEMU_OPTION_set, 418 "-set group.id.arg=value\n" 419 " set <arg> parameter for item <id> of type <group>\n" 420 " i.e. -set drive.$id.file=/path/to/image\n", QEMU_ARCH_ALL) 421SRST 422``-set group.id.arg=value`` 423 Set parameter arg for item id of type group 424ERST 425 426DEF("global", HAS_ARG, QEMU_OPTION_global, 427 "-global driver.property=value\n" 428 "-global driver=driver,property=property,value=value\n" 429 " set a global default for a driver property\n", 430 QEMU_ARCH_ALL) 431SRST 432``-global driver.prop=value`` 433 \ 434``-global driver=driver,property=property,value=value`` 435 Set default value of driver's property prop to value, e.g.: 436 437 .. parsed-literal:: 438 439 |qemu_system_x86| -global ide-hd.physical_block_size=4096 disk-image.img 440 441 In particular, you can use this to set driver properties for devices 442 which are created automatically by the machine model. To create a 443 device which is not created automatically and set properties on it, 444 use -``device``. 445 446 -global driver.prop=value is shorthand for -global 447 driver=driver,property=prop,value=value. The longhand syntax works 448 even when driver contains a dot. 449ERST 450 451DEF("boot", HAS_ARG, QEMU_OPTION_boot, 452 "-boot [order=drives][,once=drives][,menu=on|off]\n" 453 " [,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_time][,strict=on|off]\n" 454 " 'drives': floppy (a), hard disk (c), CD-ROM (d), network (n)\n" 455 " 'sp_name': the file's name that would be passed to bios as logo picture, if menu=on\n" 456 " 'sp_time': the period that splash picture last if menu=on, unit is ms\n" 457 " 'rb_timeout': the timeout before guest reboot when boot failed, unit is ms\n", 458 QEMU_ARCH_ALL) 459SRST 460``-boot [order=drives][,once=drives][,menu=on|off][,splash=sp_name][,splash-time=sp_time][,reboot-timeout=rb_timeout][,strict=on|off]`` 461 Specify boot order drives as a string of drive letters. Valid drive 462 letters depend on the target architecture. The x86 PC uses: a, b 463 (floppy 1 and 2), c (first hard disk), d (first CD-ROM), n-p 464 (Etherboot from network adapter 1-4), hard disk boot is the default. 465 To apply a particular boot order only on the first startup, specify 466 it via ``once``. Note that the ``order`` or ``once`` parameter 467 should not be used together with the ``bootindex`` property of 468 devices, since the firmware implementations normally do not support 469 both at the same time. 470 471 Interactive boot menus/prompts can be enabled via ``menu=on`` as far 472 as firmware/BIOS supports them. The default is non-interactive boot. 473 474 A splash picture could be passed to bios, enabling user to show it 475 as logo, when option splash=sp\_name is given and menu=on, If 476 firmware/BIOS supports them. Currently Seabios for X86 system 477 support it. limitation: The splash file could be a jpeg file or a 478 BMP file in 24 BPP format(true color). The resolution should be 479 supported by the SVGA mode, so the recommended is 320x240, 640x480, 480 800x640. 481 482 A timeout could be passed to bios, guest will pause for rb\_timeout 483 ms when boot failed, then reboot. If rb\_timeout is '-1', guest will 484 not reboot, qemu passes '-1' to bios by default. Currently Seabios 485 for X86 system support it. 486 487 Do strict boot via ``strict=on`` as far as firmware/BIOS supports 488 it. This only effects when boot priority is changed by bootindex 489 options. The default is non-strict boot. 490 491 .. parsed-literal:: 492 493 # try to boot from network first, then from hard disk 494 |qemu_system_x86| -boot order=nc 495 # boot from CD-ROM first, switch back to default order after reboot 496 |qemu_system_x86| -boot once=d 497 # boot with a splash picture for 5 seconds. 498 |qemu_system_x86| -boot menu=on,splash=/root/boot.bmp,splash-time=5000 499 500 Note: The legacy format '-boot drives' is still supported but its 501 use is discouraged as it may be removed from future versions. 502ERST 503 504DEF("m", HAS_ARG, QEMU_OPTION_m, 505 "-m [size=]megs[,slots=n,maxmem=size]\n" 506 " configure guest RAM\n" 507 " size: initial amount of guest memory\n" 508 " slots: number of hotplug slots (default: none)\n" 509 " maxmem: maximum amount of guest memory (default: none)\n" 510 "NOTE: Some architectures might enforce a specific granularity\n", 511 QEMU_ARCH_ALL) 512SRST 513``-m [size=]megs[,slots=n,maxmem=size]`` 514 Sets guest startup RAM size to megs megabytes. Default is 128 MiB. 515 Optionally, a suffix of "M" or "G" can be used to signify a value in 516 megabytes or gigabytes respectively. Optional pair slots, maxmem 517 could be used to set amount of hotpluggable memory slots and maximum 518 amount of memory. Note that maxmem must be aligned to the page size. 519 520 For example, the following command-line sets the guest startup RAM 521 size to 1GB, creates 3 slots to hotplug additional memory and sets 522 the maximum memory the guest can reach to 4GB: 523 524 .. parsed-literal:: 525 526 |qemu_system| -m 1G,slots=3,maxmem=4G 527 528 If slots and maxmem are not specified, memory hotplug won't be 529 enabled and the guest startup RAM will never increase. 530ERST 531 532DEF("mem-path", HAS_ARG, QEMU_OPTION_mempath, 533 "-mem-path FILE provide backing storage for guest RAM\n", QEMU_ARCH_ALL) 534SRST 535``-mem-path path`` 536 Allocate guest RAM from a temporarily created file in path. 537ERST 538 539DEF("mem-prealloc", 0, QEMU_OPTION_mem_prealloc, 540 "-mem-prealloc preallocate guest memory (use with -mem-path)\n", 541 QEMU_ARCH_ALL) 542SRST 543``-mem-prealloc`` 544 Preallocate memory when using -mem-path. 545ERST 546 547DEF("k", HAS_ARG, QEMU_OPTION_k, 548 "-k language use keyboard layout (for example 'fr' for French)\n", 549 QEMU_ARCH_ALL) 550SRST 551``-k language`` 552 Use keyboard layout language (for example ``fr`` for French). This 553 option is only needed where it is not easy to get raw PC keycodes 554 (e.g. on Macs, with some X11 servers or with a VNC or curses 555 display). You don't normally need to use it on PC/Linux or 556 PC/Windows hosts. 557 558 The available layouts are: 559 560 :: 561 562 ar de-ch es fo fr-ca hu ja mk no pt-br sv 563 da en-gb et fr fr-ch is lt nl pl ru th 564 de en-us fi fr-be hr it lv nl-be pt sl tr 565 566 The default is ``en-us``. 567ERST 568 569 570HXCOMM Deprecated by -audiodev 571DEF("audio-help", 0, QEMU_OPTION_audio_help, 572 "-audio-help show -audiodev equivalent of the currently specified audio settings\n", 573 QEMU_ARCH_ALL) 574SRST 575``-audio-help`` 576 Will show the -audiodev equivalent of the currently specified 577 (deprecated) environment variables. 578ERST 579 580DEF("audiodev", HAS_ARG, QEMU_OPTION_audiodev, 581 "-audiodev [driver=]driver,id=id[,prop[=value][,...]]\n" 582 " specifies the audio backend to use\n" 583 " id= identifier of the backend\n" 584 " timer-period= timer period in microseconds\n" 585 " in|out.mixing-engine= use mixing engine to mix streams inside QEMU\n" 586 " in|out.fixed-settings= use fixed settings for host audio\n" 587 " in|out.frequency= frequency to use with fixed settings\n" 588 " in|out.channels= number of channels to use with fixed settings\n" 589 " in|out.format= sample format to use with fixed settings\n" 590 " valid values: s8, s16, s32, u8, u16, u32, f32\n" 591 " in|out.voices= number of voices to use\n" 592 " in|out.buffer-length= length of buffer in microseconds\n" 593 "-audiodev none,id=id,[,prop[=value][,...]]\n" 594 " dummy driver that discards all output\n" 595#ifdef CONFIG_AUDIO_ALSA 596 "-audiodev alsa,id=id[,prop[=value][,...]]\n" 597 " in|out.dev= name of the audio device to use\n" 598 " in|out.period-length= length of period in microseconds\n" 599 " in|out.try-poll= attempt to use poll mode\n" 600 " threshold= threshold (in microseconds) when playback starts\n" 601#endif 602#ifdef CONFIG_AUDIO_COREAUDIO 603 "-audiodev coreaudio,id=id[,prop[=value][,...]]\n" 604 " in|out.buffer-count= number of buffers\n" 605#endif 606#ifdef CONFIG_AUDIO_DSOUND 607 "-audiodev dsound,id=id[,prop[=value][,...]]\n" 608 " latency= add extra latency to playback in microseconds\n" 609#endif 610#ifdef CONFIG_AUDIO_OSS 611 "-audiodev oss,id=id[,prop[=value][,...]]\n" 612 " in|out.dev= path of the audio device to use\n" 613 " in|out.buffer-count= number of buffers\n" 614 " in|out.try-poll= attempt to use poll mode\n" 615 " try-mmap= try using memory mapped access\n" 616 " exclusive= open device in exclusive mode\n" 617 " dsp-policy= set timing policy (0..10), -1 to use fragment mode\n" 618#endif 619#ifdef CONFIG_AUDIO_PA 620 "-audiodev pa,id=id[,prop[=value][,...]]\n" 621 " server= PulseAudio server address\n" 622 " in|out.name= source/sink device name\n" 623 " in|out.latency= desired latency in microseconds\n" 624#endif 625#ifdef CONFIG_AUDIO_SDL 626 "-audiodev sdl,id=id[,prop[=value][,...]]\n" 627 " in|out.buffer-count= number of buffers\n" 628#endif 629#ifdef CONFIG_SPICE 630 "-audiodev spice,id=id[,prop[=value][,...]]\n" 631#endif 632 "-audiodev wav,id=id[,prop[=value][,...]]\n" 633 " path= path of wav file to record\n", 634 QEMU_ARCH_ALL) 635SRST 636``-audiodev [driver=]driver,id=id[,prop[=value][,...]]`` 637 Adds a new audio backend driver identified by id. There are global 638 and driver specific properties. Some values can be set differently 639 for input and output, they're marked with ``in|out.``. You can set 640 the input's property with ``in.prop`` and the output's property with 641 ``out.prop``. For example: 642 643 :: 644 645 -audiodev alsa,id=example,in.frequency=44110,out.frequency=8000 646 -audiodev alsa,id=example,out.channels=1 # leaves in.channels unspecified 647 648 NOTE: parameter validation is known to be incomplete, in many cases 649 specifying an invalid option causes QEMU to print an error message 650 and continue emulation without sound. 651 652 Valid global options are: 653 654 ``id=identifier`` 655 Identifies the audio backend. 656 657 ``timer-period=period`` 658 Sets the timer period used by the audio subsystem in 659 microseconds. Default is 10000 (10 ms). 660 661 ``in|out.mixing-engine=on|off`` 662 Use QEMU's mixing engine to mix all streams inside QEMU and 663 convert audio formats when not supported by the backend. When 664 off, fixed-settings must be off too. Note that disabling this 665 option means that the selected backend must support multiple 666 streams and the audio formats used by the virtual cards, 667 otherwise you'll get no sound. It's not recommended to disable 668 this option unless you want to use 5.1 or 7.1 audio, as mixing 669 engine only supports mono and stereo audio. Default is on. 670 671 ``in|out.fixed-settings=on|off`` 672 Use fixed settings for host audio. When off, it will change 673 based on how the guest opens the sound card. In this case you 674 must not specify frequency, channels or format. Default is on. 675 676 ``in|out.frequency=frequency`` 677 Specify the frequency to use when using fixed-settings. Default 678 is 44100Hz. 679 680 ``in|out.channels=channels`` 681 Specify the number of channels to use when using fixed-settings. 682 Default is 2 (stereo). 683 684 ``in|out.format=format`` 685 Specify the sample format to use when using fixed-settings. 686 Valid values are: ``s8``, ``s16``, ``s32``, ``u8``, ``u16``, 687 ``u32``, ``f32``. Default is ``s16``. 688 689 ``in|out.voices=voices`` 690 Specify the number of voices to use. Default is 1. 691 692 ``in|out.buffer-length=usecs`` 693 Sets the size of the buffer in microseconds. 694 695``-audiodev none,id=id[,prop[=value][,...]]`` 696 Creates a dummy backend that discards all outputs. This backend has 697 no backend specific properties. 698 699``-audiodev alsa,id=id[,prop[=value][,...]]`` 700 Creates backend using the ALSA. This backend is only available on 701 Linux. 702 703 ALSA specific options are: 704 705 ``in|out.dev=device`` 706 Specify the ALSA device to use for input and/or output. Default 707 is ``default``. 708 709 ``in|out.period-length=usecs`` 710 Sets the period length in microseconds. 711 712 ``in|out.try-poll=on|off`` 713 Attempt to use poll mode with the device. Default is on. 714 715 ``threshold=threshold`` 716 Threshold (in microseconds) when playback starts. Default is 0. 717 718``-audiodev coreaudio,id=id[,prop[=value][,...]]`` 719 Creates a backend using Apple's Core Audio. This backend is only 720 available on Mac OS and only supports playback. 721 722 Core Audio specific options are: 723 724 ``in|out.buffer-count=count`` 725 Sets the count of the buffers. 726 727``-audiodev dsound,id=id[,prop[=value][,...]]`` 728 Creates a backend using Microsoft's DirectSound. This backend is 729 only available on Windows and only supports playback. 730 731 DirectSound specific options are: 732 733 ``latency=usecs`` 734 Add extra usecs microseconds latency to playback. Default is 735 10000 (10 ms). 736 737``-audiodev oss,id=id[,prop[=value][,...]]`` 738 Creates a backend using OSS. This backend is available on most 739 Unix-like systems. 740 741 OSS specific options are: 742 743 ``in|out.dev=device`` 744 Specify the file name of the OSS device to use. Default is 745 ``/dev/dsp``. 746 747 ``in|out.buffer-count=count`` 748 Sets the count of the buffers. 749 750 ``in|out.try-poll=on|of`` 751 Attempt to use poll mode with the device. Default is on. 752 753 ``try-mmap=on|off`` 754 Try using memory mapped device access. Default is off. 755 756 ``exclusive=on|off`` 757 Open the device in exclusive mode (vmix won't work in this 758 case). Default is off. 759 760 ``dsp-policy=policy`` 761 Sets the timing policy (between 0 and 10, where smaller number 762 means smaller latency but higher CPU usage). Use -1 to use 763 buffer sizes specified by ``buffer`` and ``buffer-count``. This 764 option is ignored if you do not have OSS 4. Default is 5. 765 766``-audiodev pa,id=id[,prop[=value][,...]]`` 767 Creates a backend using PulseAudio. This backend is available on 768 most systems. 769 770 PulseAudio specific options are: 771 772 ``server=server`` 773 Sets the PulseAudio server to connect to. 774 775 ``in|out.name=sink`` 776 Use the specified source/sink for recording/playback. 777 778 ``in|out.latency=usecs`` 779 Desired latency in microseconds. The PulseAudio server will try 780 to honor this value but actual latencies may be lower or higher. 781 782``-audiodev sdl,id=id[,prop[=value][,...]]`` 783 Creates a backend using SDL. This backend is available on most 784 systems, but you should use your platform's native backend if 785 possible. 786 787 SDL specific options are: 788 789 ``in|out.buffer-count=count`` 790 Sets the count of the buffers. 791 792``-audiodev spice,id=id[,prop[=value][,...]]`` 793 Creates a backend that sends audio through SPICE. This backend 794 requires ``-spice`` and automatically selected in that case, so 795 usually you can ignore this option. This backend has no backend 796 specific properties. 797 798``-audiodev wav,id=id[,prop[=value][,...]]`` 799 Creates a backend that writes audio to a WAV file. 800 801 Backend specific options are: 802 803 ``path=path`` 804 Write recorded audio into the specified file. Default is 805 ``qemu.wav``. 806ERST 807 808DEF("soundhw", HAS_ARG, QEMU_OPTION_soundhw, 809 "-soundhw c1,... enable audio support\n" 810 " and only specified sound cards (comma separated list)\n" 811 " use '-soundhw help' to get the list of supported cards\n" 812 " use '-soundhw all' to enable all of them\n", QEMU_ARCH_ALL) 813SRST 814``-soundhw card1[,card2,...] or -soundhw all`` 815 Enable audio and selected sound hardware. Use 'help' to print all 816 available sound hardware. For example: 817 818 .. parsed-literal:: 819 820 |qemu_system_x86| -soundhw sb16,adlib disk.img 821 |qemu_system_x86| -soundhw es1370 disk.img 822 |qemu_system_x86| -soundhw ac97 disk.img 823 |qemu_system_x86| -soundhw hda disk.img 824 |qemu_system_x86| -soundhw all disk.img 825 |qemu_system_x86| -soundhw help 826 827 Note that Linux's i810\_audio OSS kernel (for AC97) module might 828 require manually specifying clocking. 829 830 :: 831 832 modprobe i810_audio clocking=48000 833ERST 834 835DEF("device", HAS_ARG, QEMU_OPTION_device, 836 "-device driver[,prop[=value][,...]]\n" 837 " add device (based on driver)\n" 838 " prop=value,... sets driver properties\n" 839 " use '-device help' to print all possible drivers\n" 840 " use '-device driver,help' to print all possible properties\n", 841 QEMU_ARCH_ALL) 842SRST 843``-device driver[,prop[=value][,...]]`` 844 Add device driver. prop=value sets driver properties. Valid 845 properties depend on the driver. To get help on possible drivers and 846 properties, use ``-device help`` and ``-device driver,help``. 847 848 Some drivers are: 849 850``-device ipmi-bmc-sim,id=id[,prop[=value][,...]]`` 851 Add an IPMI BMC. This is a simulation of a hardware management 852 interface processor that normally sits on a system. It provides a 853 watchdog and the ability to reset and power control the system. You 854 need to connect this to an IPMI interface to make it useful 855 856 The IPMI slave address to use for the BMC. The default is 0x20. This 857 address is the BMC's address on the I2C network of management 858 controllers. If you don't know what this means, it is safe to ignore 859 it. 860 861 ``id=id`` 862 The BMC id for interfaces to use this device. 863 864 ``slave_addr=val`` 865 Define slave address to use for the BMC. The default is 0x20. 866 867 ``sdrfile=file`` 868 file containing raw Sensor Data Records (SDR) data. The default 869 is none. 870 871 ``fruareasize=val`` 872 size of a Field Replaceable Unit (FRU) area. The default is 873 1024. 874 875 ``frudatafile=file`` 876 file containing raw Field Replaceable Unit (FRU) inventory data. 877 The default is none. 878 879 ``guid=uuid`` 880 value for the GUID for the BMC, in standard UUID format. If this 881 is set, get "Get GUID" command to the BMC will return it. 882 Otherwise "Get GUID" will return an error. 883 884``-device ipmi-bmc-extern,id=id,chardev=id[,slave_addr=val]`` 885 Add a connection to an external IPMI BMC simulator. Instead of 886 locally emulating the BMC like the above item, instead connect to an 887 external entity that provides the IPMI services. 888 889 A connection is made to an external BMC simulator. If you do this, 890 it is strongly recommended that you use the "reconnect=" chardev 891 option to reconnect to the simulator if the connection is lost. Note 892 that if this is not used carefully, it can be a security issue, as 893 the interface has the ability to send resets, NMIs, and power off 894 the VM. It's best if QEMU makes a connection to an external 895 simulator running on a secure port on localhost, so neither the 896 simulator nor QEMU is exposed to any outside network. 897 898 See the "lanserv/README.vm" file in the OpenIPMI library for more 899 details on the external interface. 900 901``-device isa-ipmi-kcs,bmc=id[,ioport=val][,irq=val]`` 902 Add a KCS IPMI interafce on the ISA bus. This also adds a 903 corresponding ACPI and SMBIOS entries, if appropriate. 904 905 ``bmc=id`` 906 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern 907 above. 908 909 ``ioport=val`` 910 Define the I/O address of the interface. The default is 0xca0 911 for KCS. 912 913 ``irq=val`` 914 Define the interrupt to use. The default is 5. To disable 915 interrupts, set this to 0. 916 917``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]`` 918 Like the KCS interface, but defines a BT interface. The default port 919 is 0xe4 and the default interrupt is 5. 920 921``-device pci-ipmi-kcs,bmc=id`` 922 Add a KCS IPMI interafce on the PCI bus. 923 924 ``bmc=id`` 925 The BMC to connect to, one of ipmi-bmc-sim or ipmi-bmc-extern above. 926 927``-device pci-ipmi-bt,bmc=id`` 928 Like the KCS interface, but defines a BT interface on the PCI bus. 929ERST 930 931DEF("name", HAS_ARG, QEMU_OPTION_name, 932 "-name string1[,process=string2][,debug-threads=on|off]\n" 933 " set the name of the guest\n" 934 " string1 sets the window title and string2 the process name\n" 935 " When debug-threads is enabled, individual threads are given a separate name\n" 936 " NOTE: The thread names are for debugging and not a stable API.\n", 937 QEMU_ARCH_ALL) 938SRST 939``-name name`` 940 Sets the name of the guest. This name will be displayed in the SDL 941 window caption. The name will also be used for the VNC server. Also 942 optionally set the top visible process name in Linux. Naming of 943 individual threads can also be enabled on Linux to aid debugging. 944ERST 945 946DEF("uuid", HAS_ARG, QEMU_OPTION_uuid, 947 "-uuid %08x-%04x-%04x-%04x-%012x\n" 948 " specify machine UUID\n", QEMU_ARCH_ALL) 949SRST 950``-uuid uuid`` 951 Set system UUID. 952ERST 953 954DEFHEADING() 955 956DEFHEADING(Block device options:) 957 958DEF("fda", HAS_ARG, QEMU_OPTION_fda, 959 "-fda/-fdb file use 'file' as floppy disk 0/1 image\n", QEMU_ARCH_ALL) 960DEF("fdb", HAS_ARG, QEMU_OPTION_fdb, "", QEMU_ARCH_ALL) 961SRST 962``-fda file`` 963 \ 964``-fdb file`` 965 Use file as floppy disk 0/1 image (see the :ref:`disk images` chapter in 966 the System Emulation Users Guide). 967ERST 968 969DEF("hda", HAS_ARG, QEMU_OPTION_hda, 970 "-hda/-hdb file use 'file' as IDE hard disk 0/1 image\n", QEMU_ARCH_ALL) 971DEF("hdb", HAS_ARG, QEMU_OPTION_hdb, "", QEMU_ARCH_ALL) 972DEF("hdc", HAS_ARG, QEMU_OPTION_hdc, 973 "-hdc/-hdd file use 'file' as IDE hard disk 2/3 image\n", QEMU_ARCH_ALL) 974DEF("hdd", HAS_ARG, QEMU_OPTION_hdd, "", QEMU_ARCH_ALL) 975SRST 976``-hda file`` 977 \ 978``-hdb file`` 979 \ 980``-hdc file`` 981 \ 982``-hdd file`` 983 Use file as hard disk 0, 1, 2 or 3 image (see the :ref:`disk images` 984 chapter in the System Emulation Users Guide). 985ERST 986 987DEF("cdrom", HAS_ARG, QEMU_OPTION_cdrom, 988 "-cdrom file use 'file' as IDE cdrom image (cdrom is ide1 master)\n", 989 QEMU_ARCH_ALL) 990SRST 991``-cdrom file`` 992 Use file as CD-ROM image (you cannot use ``-hdc`` and ``-cdrom`` at 993 the same time). You can use the host CD-ROM by using ``/dev/cdrom`` 994 as filename. 995ERST 996 997DEF("blockdev", HAS_ARG, QEMU_OPTION_blockdev, 998 "-blockdev [driver=]driver[,node-name=N][,discard=ignore|unmap]\n" 999 " [,cache.direct=on|off][,cache.no-flush=on|off]\n" 1000 " [,read-only=on|off][,auto-read-only=on|off]\n" 1001 " [,force-share=on|off][,detect-zeroes=on|off|unmap]\n" 1002 " [,driver specific parameters...]\n" 1003 " configure a block backend\n", QEMU_ARCH_ALL) 1004SRST 1005``-blockdev option[,option[,option[,...]]]`` 1006 Define a new block driver node. Some of the options apply to all 1007 block drivers, other options are only accepted for a specific block 1008 driver. See below for a list of generic options and options for the 1009 most common block drivers. 1010 1011 Options that expect a reference to another node (e.g. ``file``) can 1012 be given in two ways. Either you specify the node name of an already 1013 existing node (file=node-name), or you define a new node inline, 1014 adding options for the referenced node after a dot 1015 (file.filename=path,file.aio=native). 1016 1017 A block driver node created with ``-blockdev`` can be used for a 1018 guest device by specifying its node name for the ``drive`` property 1019 in a ``-device`` argument that defines a block device. 1020 1021 ``Valid options for any block driver node:`` 1022 ``driver`` 1023 Specifies the block driver to use for the given node. 1024 1025 ``node-name`` 1026 This defines the name of the block driver node by which it 1027 will be referenced later. The name must be unique, i.e. it 1028 must not match the name of a different block driver node, or 1029 (if you use ``-drive`` as well) the ID of a drive. 1030 1031 If no node name is specified, it is automatically generated. 1032 The generated node name is not intended to be predictable 1033 and changes between QEMU invocations. For the top level, an 1034 explicit node name must be specified. 1035 1036 ``read-only`` 1037 Open the node read-only. Guest write attempts will fail. 1038 1039 Note that some block drivers support only read-only access, 1040 either generally or in certain configurations. In this case, 1041 the default value ``read-only=off`` does not work and the 1042 option must be specified explicitly. 1043 1044 ``auto-read-only`` 1045 If ``auto-read-only=on`` is set, QEMU may fall back to 1046 read-only usage even when ``read-only=off`` is requested, or 1047 even switch between modes as needed, e.g. depending on 1048 whether the image file is writable or whether a writing user 1049 is attached to the node. 1050 1051 ``force-share`` 1052 Override the image locking system of QEMU by forcing the 1053 node to utilize weaker shared access for permissions where 1054 it would normally request exclusive access. When there is 1055 the potential for multiple instances to have the same file 1056 open (whether this invocation of QEMU is the first or the 1057 second instance), both instances must permit shared access 1058 for the second instance to succeed at opening the file. 1059 1060 Enabling ``force-share=on`` requires ``read-only=on``. 1061 1062 ``cache.direct`` 1063 The host page cache can be avoided with ``cache.direct=on``. 1064 This will attempt to do disk IO directly to the guest's 1065 memory. QEMU may still perform an internal copy of the data. 1066 1067 ``cache.no-flush`` 1068 In case you don't care about data integrity over host 1069 failures, you can use ``cache.no-flush=on``. This option 1070 tells QEMU that it never needs to write any data to the disk 1071 but can instead keep things in cache. If anything goes 1072 wrong, like your host losing power, the disk storage getting 1073 disconnected accidentally, etc. your image will most 1074 probably be rendered unusable. 1075 1076 ``discard=discard`` 1077 discard is one of "ignore" (or "off") or "unmap" (or "on") 1078 and controls whether ``discard`` (also known as ``trim`` or 1079 ``unmap``) requests are ignored or passed to the filesystem. 1080 Some machine types may not support discard requests. 1081 1082 ``detect-zeroes=detect-zeroes`` 1083 detect-zeroes is "off", "on" or "unmap" and enables the 1084 automatic conversion of plain zero writes by the OS to 1085 driver specific optimized zero write commands. You may even 1086 choose "unmap" if discard is set to "unmap" to allow a zero 1087 write to be converted to an ``unmap`` operation. 1088 1089 ``Driver-specific options for file`` 1090 This is the protocol-level block driver for accessing regular 1091 files. 1092 1093 ``filename`` 1094 The path to the image file in the local filesystem 1095 1096 ``aio`` 1097 Specifies the AIO backend (threads/native/io_uring, 1098 default: threads) 1099 1100 ``locking`` 1101 Specifies whether the image file is protected with Linux OFD 1102 / POSIX locks. The default is to use the Linux Open File 1103 Descriptor API if available, otherwise no lock is applied. 1104 (auto/on/off, default: auto) 1105 1106 Example: 1107 1108 :: 1109 1110 -blockdev driver=file,node-name=disk,filename=disk.img 1111 1112 ``Driver-specific options for raw`` 1113 This is the image format block driver for raw images. It is 1114 usually stacked on top of a protocol level block driver such as 1115 ``file``. 1116 1117 ``file`` 1118 Reference to or definition of the data source block driver 1119 node (e.g. a ``file`` driver node) 1120 1121 Example 1: 1122 1123 :: 1124 1125 -blockdev driver=file,node-name=disk_file,filename=disk.img 1126 -blockdev driver=raw,node-name=disk,file=disk_file 1127 1128 Example 2: 1129 1130 :: 1131 1132 -blockdev driver=raw,node-name=disk,file.driver=file,file.filename=disk.img 1133 1134 ``Driver-specific options for qcow2`` 1135 This is the image format block driver for qcow2 images. It is 1136 usually stacked on top of a protocol level block driver such as 1137 ``file``. 1138 1139 ``file`` 1140 Reference to or definition of the data source block driver 1141 node (e.g. a ``file`` driver node) 1142 1143 ``backing`` 1144 Reference to or definition of the backing file block device 1145 (default is taken from the image file). It is allowed to 1146 pass ``null`` here in order to disable the default backing 1147 file. 1148 1149 ``lazy-refcounts`` 1150 Whether to enable the lazy refcounts feature (on/off; 1151 default is taken from the image file) 1152 1153 ``cache-size`` 1154 The maximum total size of the L2 table and refcount block 1155 caches in bytes (default: the sum of l2-cache-size and 1156 refcount-cache-size) 1157 1158 ``l2-cache-size`` 1159 The maximum size of the L2 table cache in bytes (default: if 1160 cache-size is not specified - 32M on Linux platforms, and 8M 1161 on non-Linux platforms; otherwise, as large as possible 1162 within the cache-size, while permitting the requested or the 1163 minimal refcount cache size) 1164 1165 ``refcount-cache-size`` 1166 The maximum size of the refcount block cache in bytes 1167 (default: 4 times the cluster size; or if cache-size is 1168 specified, the part of it which is not used for the L2 1169 cache) 1170 1171 ``cache-clean-interval`` 1172 Clean unused entries in the L2 and refcount caches. The 1173 interval is in seconds. The default value is 600 on 1174 supporting platforms, and 0 on other platforms. Setting it 1175 to 0 disables this feature. 1176 1177 ``pass-discard-request`` 1178 Whether discard requests to the qcow2 device should be 1179 forwarded to the data source (on/off; default: on if 1180 discard=unmap is specified, off otherwise) 1181 1182 ``pass-discard-snapshot`` 1183 Whether discard requests for the data source should be 1184 issued when a snapshot operation (e.g. deleting a snapshot) 1185 frees clusters in the qcow2 file (on/off; default: on) 1186 1187 ``pass-discard-other`` 1188 Whether discard requests for the data source should be 1189 issued on other occasions where a cluster gets freed 1190 (on/off; default: off) 1191 1192 ``overlap-check`` 1193 Which overlap checks to perform for writes to the image 1194 (none/constant/cached/all; default: cached). For details or 1195 finer granularity control refer to the QAPI documentation of 1196 ``blockdev-add``. 1197 1198 Example 1: 1199 1200 :: 1201 1202 -blockdev driver=file,node-name=my_file,filename=/tmp/disk.qcow2 1203 -blockdev driver=qcow2,node-name=hda,file=my_file,overlap-check=none,cache-size=16777216 1204 1205 Example 2: 1206 1207 :: 1208 1209 -blockdev driver=qcow2,node-name=disk,file.driver=http,file.filename=http://example.com/image.qcow2 1210 1211 ``Driver-specific options for other drivers`` 1212 Please refer to the QAPI documentation of the ``blockdev-add`` 1213 QMP command. 1214ERST 1215 1216DEF("drive", HAS_ARG, QEMU_OPTION_drive, 1217 "-drive [file=file][,if=type][,bus=n][,unit=m][,media=d][,index=i]\n" 1218 " [,cache=writethrough|writeback|none|directsync|unsafe][,format=f]\n" 1219 " [,snapshot=on|off][,rerror=ignore|stop|report]\n" 1220 " [,werror=ignore|stop|report|enospc][,id=name]\n" 1221 " [,aio=threads|native|io_uring]\n" 1222 " [,readonly=on|off][,copy-on-read=on|off]\n" 1223 " [,discard=ignore|unmap][,detect-zeroes=on|off|unmap]\n" 1224 " [[,bps=b]|[[,bps_rd=r][,bps_wr=w]]]\n" 1225 " [[,iops=i]|[[,iops_rd=r][,iops_wr=w]]]\n" 1226 " [[,bps_max=bm]|[[,bps_rd_max=rm][,bps_wr_max=wm]]]\n" 1227 " [[,iops_max=im]|[[,iops_rd_max=irm][,iops_wr_max=iwm]]]\n" 1228 " [[,iops_size=is]]\n" 1229 " [[,group=g]]\n" 1230 " use 'file' as a drive image\n", QEMU_ARCH_ALL) 1231SRST 1232``-drive option[,option[,option[,...]]]`` 1233 Define a new drive. This includes creating a block driver node (the 1234 backend) as well as a guest device, and is mostly a shortcut for 1235 defining the corresponding ``-blockdev`` and ``-device`` options. 1236 1237 ``-drive`` accepts all options that are accepted by ``-blockdev``. 1238 In addition, it knows the following options: 1239 1240 ``file=file`` 1241 This option defines which disk image (see the :ref:`disk images` 1242 chapter in the System Emulation Users Guide) to use with this drive. 1243 If the filename contains comma, you must double it (for instance, 1244 "file=my,,file" to use file "my,file"). 1245 1246 Special files such as iSCSI devices can be specified using 1247 protocol specific URLs. See the section for "Device URL Syntax" 1248 for more information. 1249 1250 ``if=interface`` 1251 This option defines on which type on interface the drive is 1252 connected. Available types are: ide, scsi, sd, mtd, floppy, 1253 pflash, virtio, none. 1254 1255 ``bus=bus,unit=unit`` 1256 These options define where is connected the drive by defining 1257 the bus number and the unit id. 1258 1259 ``index=index`` 1260 This option defines where is connected the drive by using an 1261 index in the list of available connectors of a given interface 1262 type. 1263 1264 ``media=media`` 1265 This option defines the type of the media: disk or cdrom. 1266 1267 ``snapshot=snapshot`` 1268 snapshot is "on" or "off" and controls snapshot mode for the 1269 given drive (see ``-snapshot``). 1270 1271 ``cache=cache`` 1272 cache is "none", "writeback", "unsafe", "directsync" or 1273 "writethrough" and controls how the host cache is used to access 1274 block data. This is a shortcut that sets the ``cache.direct`` 1275 and ``cache.no-flush`` options (as in ``-blockdev``), and 1276 additionally ``cache.writeback``, which provides a default for 1277 the ``write-cache`` option of block guest devices (as in 1278 ``-device``). The modes correspond to the following settings: 1279 1280 ============= =============== ============ ============== 1281 \ cache.writeback cache.direct cache.no-flush 1282 ============= =============== ============ ============== 1283 writeback on off off 1284 none on on off 1285 writethrough off off off 1286 directsync off on off 1287 unsafe on off on 1288 ============= =============== ============ ============== 1289 1290 The default mode is ``cache=writeback``. 1291 1292 ``aio=aio`` 1293 aio is "threads", "native", or "io_uring" and selects between pthread 1294 based disk I/O, native Linux AIO, or Linux io_uring API. 1295 1296 ``format=format`` 1297 Specify which disk format will be used rather than detecting the 1298 format. Can be used to specify format=raw to avoid interpreting 1299 an untrusted format header. 1300 1301 ``werror=action,rerror=action`` 1302 Specify which action to take on write and read errors. Valid 1303 actions are: "ignore" (ignore the error and try to continue), 1304 "stop" (pause QEMU), "report" (report the error to the guest), 1305 "enospc" (pause QEMU only if the host disk is full; report the 1306 error to the guest otherwise). The default setting is 1307 ``werror=enospc`` and ``rerror=report``. 1308 1309 ``copy-on-read=copy-on-read`` 1310 copy-on-read is "on" or "off" and enables whether to copy read 1311 backing file sectors into the image file. 1312 1313 ``bps=b,bps_rd=r,bps_wr=w`` 1314 Specify bandwidth throttling limits in bytes per second, either 1315 for all request types or for reads or writes only. Small values 1316 can lead to timeouts or hangs inside the guest. A safe minimum 1317 for disks is 2 MB/s. 1318 1319 ``bps_max=bm,bps_rd_max=rm,bps_wr_max=wm`` 1320 Specify bursts in bytes per second, either for all request types 1321 or for reads or writes only. Bursts allow the guest I/O to spike 1322 above the limit temporarily. 1323 1324 ``iops=i,iops_rd=r,iops_wr=w`` 1325 Specify request rate limits in requests per second, either for 1326 all request types or for reads or writes only. 1327 1328 ``iops_max=bm,iops_rd_max=rm,iops_wr_max=wm`` 1329 Specify bursts in requests per second, either for all request 1330 types or for reads or writes only. Bursts allow the guest I/O to 1331 spike above the limit temporarily. 1332 1333 ``iops_size=is`` 1334 Let every is bytes of a request count as a new request for iops 1335 throttling purposes. Use this option to prevent guests from 1336 circumventing iops limits by sending fewer but larger requests. 1337 1338 ``group=g`` 1339 Join a throttling quota group with given name g. All drives that 1340 are members of the same group are accounted for together. Use 1341 this option to prevent guests from circumventing throttling 1342 limits by using many small disks instead of a single larger 1343 disk. 1344 1345 By default, the ``cache.writeback=on`` mode is used. It will report 1346 data writes as completed as soon as the data is present in the host 1347 page cache. This is safe as long as your guest OS makes sure to 1348 correctly flush disk caches where needed. If your guest OS does not 1349 handle volatile disk write caches correctly and your host crashes or 1350 loses power, then the guest may experience data corruption. 1351 1352 For such guests, you should consider using ``cache.writeback=off``. 1353 This means that the host page cache will be used to read and write 1354 data, but write notification will be sent to the guest only after 1355 QEMU has made sure to flush each write to the disk. Be aware that 1356 this has a major impact on performance. 1357 1358 When using the ``-snapshot`` option, unsafe caching is always used. 1359 1360 Copy-on-read avoids accessing the same backing file sectors 1361 repeatedly and is useful when the backing file is over a slow 1362 network. By default copy-on-read is off. 1363 1364 Instead of ``-cdrom`` you can use: 1365 1366 .. parsed-literal:: 1367 1368 |qemu_system| -drive file=file,index=2,media=cdrom 1369 1370 Instead of ``-hda``, ``-hdb``, ``-hdc``, ``-hdd``, you can use: 1371 1372 .. parsed-literal:: 1373 1374 |qemu_system| -drive file=file,index=0,media=disk 1375 |qemu_system| -drive file=file,index=1,media=disk 1376 |qemu_system| -drive file=file,index=2,media=disk 1377 |qemu_system| -drive file=file,index=3,media=disk 1378 1379 You can open an image using pre-opened file descriptors from an fd 1380 set: 1381 1382 .. parsed-literal:: 1383 1384 |qemu_system| \\ 1385 -add-fd fd=3,set=2,opaque="rdwr:/path/to/file" \\ 1386 -add-fd fd=4,set=2,opaque="rdonly:/path/to/file" \\ 1387 -drive file=/dev/fdset/2,index=0,media=disk 1388 1389 You can connect a CDROM to the slave of ide0: 1390 1391 .. parsed-literal:: 1392 1393 |qemu_system_x86| -drive file=file,if=ide,index=1,media=cdrom 1394 1395 If you don't specify the "file=" argument, you define an empty 1396 drive: 1397 1398 .. parsed-literal:: 1399 1400 |qemu_system_x86| -drive if=ide,index=1,media=cdrom 1401 1402 Instead of ``-fda``, ``-fdb``, you can use: 1403 1404 .. parsed-literal:: 1405 1406 |qemu_system_x86| -drive file=file,index=0,if=floppy 1407 |qemu_system_x86| -drive file=file,index=1,if=floppy 1408 1409 By default, interface is "ide" and index is automatically 1410 incremented: 1411 1412 .. parsed-literal:: 1413 1414 |qemu_system_x86| -drive file=a -drive file=b" 1415 1416 is interpreted like: 1417 1418 .. parsed-literal:: 1419 1420 |qemu_system_x86| -hda a -hdb b 1421ERST 1422 1423DEF("mtdblock", HAS_ARG, QEMU_OPTION_mtdblock, 1424 "-mtdblock file use 'file' as on-board Flash memory image\n", 1425 QEMU_ARCH_ALL) 1426SRST 1427``-mtdblock file`` 1428 Use file as on-board Flash memory image. 1429ERST 1430 1431DEF("sd", HAS_ARG, QEMU_OPTION_sd, 1432 "-sd file use 'file' as SecureDigital card image\n", QEMU_ARCH_ALL) 1433SRST 1434``-sd file`` 1435 Use file as SecureDigital card image. 1436ERST 1437 1438DEF("pflash", HAS_ARG, QEMU_OPTION_pflash, 1439 "-pflash file use 'file' as a parallel flash image\n", QEMU_ARCH_ALL) 1440SRST 1441``-pflash file`` 1442 Use file as a parallel flash image. 1443ERST 1444 1445DEF("snapshot", 0, QEMU_OPTION_snapshot, 1446 "-snapshot write to temporary files instead of disk image files\n", 1447 QEMU_ARCH_ALL) 1448SRST 1449``-snapshot`` 1450 Write to temporary files instead of disk image files. In this case, 1451 the raw disk image you use is not written back. You can however 1452 force the write back by pressing C-a s (see the :ref:`disk images` 1453 chapter in the System Emulation Users Guide). 1454ERST 1455 1456DEF("fsdev", HAS_ARG, QEMU_OPTION_fsdev, 1457 "-fsdev local,id=id,path=path,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1458 " [,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode]\n" 1459 " [[,throttling.bps-total=b]|[[,throttling.bps-read=r][,throttling.bps-write=w]]]\n" 1460 " [[,throttling.iops-total=i]|[[,throttling.iops-read=r][,throttling.iops-write=w]]]\n" 1461 " [[,throttling.bps-total-max=bm]|[[,throttling.bps-read-max=rm][,throttling.bps-write-max=wm]]]\n" 1462 " [[,throttling.iops-total-max=im]|[[,throttling.iops-read-max=irm][,throttling.iops-write-max=iwm]]]\n" 1463 " [[,throttling.iops-size=is]]\n" 1464 "-fsdev proxy,id=id,socket=socket[,writeout=immediate][,readonly=on]\n" 1465 "-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=immediate][,readonly=on]\n" 1466 "-fsdev synth,id=id\n", 1467 QEMU_ARCH_ALL) 1468 1469SRST 1470``-fsdev local,id=id,path=path,security_model=security_model [,writeout=writeout][,readonly=on][,fmode=fmode][,dmode=dmode] [,throttling.option=value[,throttling.option=value[,...]]]`` 1471 \ 1472``-fsdev proxy,id=id,socket=socket[,writeout=writeout][,readonly=on]`` 1473 \ 1474``-fsdev proxy,id=id,sock_fd=sock_fd[,writeout=writeout][,readonly=on]`` 1475 \ 1476``-fsdev synth,id=id[,readonly=on]`` 1477 Define a new file system device. Valid options are: 1478 1479 ``local`` 1480 Accesses to the filesystem are done by QEMU. 1481 1482 ``proxy`` 1483 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1484 1485 ``synth`` 1486 Synthetic filesystem, only used by QTests. 1487 1488 ``id=id`` 1489 Specifies identifier for this device. 1490 1491 ``path=path`` 1492 Specifies the export path for the file system device. Files 1493 under this path will be available to the 9p client on the guest. 1494 1495 ``security_model=security_model`` 1496 Specifies the security model to be used for this export path. 1497 Supported security models are "passthrough", "mapped-xattr", 1498 "mapped-file" and "none". In "passthrough" security model, files 1499 are stored using the same credentials as they are created on the 1500 guest. This requires QEMU to run as root. In "mapped-xattr" 1501 security model, some of the file attributes like uid, gid, mode 1502 bits and link target are stored as file attributes. For 1503 "mapped-file" these attributes are stored in the hidden 1504 .virtfs\_metadata directory. Directories exported by this 1505 security model cannot interact with other unix tools. "none" 1506 security model is same as passthrough except the sever won't 1507 report failures if it fails to set file attributes like 1508 ownership. Security model is mandatory only for local fsdriver. 1509 Other fsdrivers (like proxy) don't take security model as a 1510 parameter. 1511 1512 ``writeout=writeout`` 1513 This is an optional argument. The only supported value is 1514 "immediate". This means that host page cache will be used to 1515 read and write data but write notification will be sent to the 1516 guest only when the data has been reported as written by the 1517 storage subsystem. 1518 1519 ``readonly=on`` 1520 Enables exporting 9p share as a readonly mount for guests. By 1521 default read-write access is given. 1522 1523 ``socket=socket`` 1524 Enables proxy filesystem driver to use passed socket file for 1525 communicating with virtfs-proxy-helper(1). 1526 1527 ``sock_fd=sock_fd`` 1528 Enables proxy filesystem driver to use passed socket descriptor 1529 for communicating with virtfs-proxy-helper(1). Usually a helper 1530 like libvirt will create socketpair and pass one of the fds as 1531 sock\_fd. 1532 1533 ``fmode=fmode`` 1534 Specifies the default mode for newly created files on the host. 1535 Works only with security models "mapped-xattr" and 1536 "mapped-file". 1537 1538 ``dmode=dmode`` 1539 Specifies the default mode for newly created directories on the 1540 host. Works only with security models "mapped-xattr" and 1541 "mapped-file". 1542 1543 ``throttling.bps-total=b,throttling.bps-read=r,throttling.bps-write=w`` 1544 Specify bandwidth throttling limits in bytes per second, either 1545 for all request types or for reads or writes only. 1546 1547 ``throttling.bps-total-max=bm,bps-read-max=rm,bps-write-max=wm`` 1548 Specify bursts in bytes per second, either for all request types 1549 or for reads or writes only. Bursts allow the guest I/O to spike 1550 above the limit temporarily. 1551 1552 ``throttling.iops-total=i,throttling.iops-read=r, throttling.iops-write=w`` 1553 Specify request rate limits in requests per second, either for 1554 all request types or for reads or writes only. 1555 1556 ``throttling.iops-total-max=im,throttling.iops-read-max=irm, throttling.iops-write-max=iwm`` 1557 Specify bursts in requests per second, either for all request 1558 types or for reads or writes only. Bursts allow the guest I/O to 1559 spike above the limit temporarily. 1560 1561 ``throttling.iops-size=is`` 1562 Let every is bytes of a request count as a new request for iops 1563 throttling purposes. 1564 1565 -fsdev option is used along with -device driver "virtio-9p-...". 1566 1567``-device virtio-9p-type,fsdev=id,mount_tag=mount_tag`` 1568 Options for virtio-9p-... driver are: 1569 1570 ``type`` 1571 Specifies the variant to be used. Supported values are "pci", 1572 "ccw" or "device", depending on the machine type. 1573 1574 ``fsdev=id`` 1575 Specifies the id value specified along with -fsdev option. 1576 1577 ``mount_tag=mount_tag`` 1578 Specifies the tag name to be used by the guest to mount this 1579 export point. 1580ERST 1581 1582DEF("virtfs", HAS_ARG, QEMU_OPTION_virtfs, 1583 "-virtfs local,path=path,mount_tag=tag,security_model=mapped-xattr|mapped-file|passthrough|none\n" 1584 " [,id=id][,writeout=immediate][,readonly=on][,fmode=fmode][,dmode=dmode][,multidevs=remap|forbid|warn]\n" 1585 "-virtfs proxy,mount_tag=tag,socket=socket[,id=id][,writeout=immediate][,readonly=on]\n" 1586 "-virtfs proxy,mount_tag=tag,sock_fd=sock_fd[,id=id][,writeout=immediate][,readonly=on]\n" 1587 "-virtfs synth,mount_tag=tag[,id=id][,readonly=on]\n", 1588 QEMU_ARCH_ALL) 1589 1590SRST 1591``-virtfs local,path=path,mount_tag=mount_tag ,security_model=security_model[,writeout=writeout][,readonly=on] [,fmode=fmode][,dmode=dmode][,multidevs=multidevs]`` 1592 \ 1593``-virtfs proxy,socket=socket,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1594 \ 1595``-virtfs proxy,sock_fd=sock_fd,mount_tag=mount_tag [,writeout=writeout][,readonly=on]`` 1596 \ 1597``-virtfs synth,mount_tag=mount_tag`` 1598 Define a new virtual filesystem device and expose it to the guest using 1599 a virtio-9p-device (a.k.a. 9pfs), which essentially means that a certain 1600 directory on host is made directly accessible by guest as a pass-through 1601 file system by using the 9P network protocol for communication between 1602 host and guests, if desired even accessible, shared by several guests 1603 simultaniously. 1604 1605 Note that ``-virtfs`` is actually just a convenience shortcut for its 1606 generalized form ``-fsdev -device virtio-9p-pci``. 1607 1608 The general form of pass-through file system options are: 1609 1610 ``local`` 1611 Accesses to the filesystem are done by QEMU. 1612 1613 ``proxy`` 1614 Accesses to the filesystem are done by virtfs-proxy-helper(1). 1615 1616 ``synth`` 1617 Synthetic filesystem, only used by QTests. 1618 1619 ``id=id`` 1620 Specifies identifier for the filesystem device 1621 1622 ``path=path`` 1623 Specifies the export path for the file system device. Files 1624 under this path will be available to the 9p client on the guest. 1625 1626 ``security_model=security_model`` 1627 Specifies the security model to be used for this export path. 1628 Supported security models are "passthrough", "mapped-xattr", 1629 "mapped-file" and "none". In "passthrough" security model, files 1630 are stored using the same credentials as they are created on the 1631 guest. This requires QEMU to run as root. In "mapped-xattr" 1632 security model, some of the file attributes like uid, gid, mode 1633 bits and link target are stored as file attributes. For 1634 "mapped-file" these attributes are stored in the hidden 1635 .virtfs\_metadata directory. Directories exported by this 1636 security model cannot interact with other unix tools. "none" 1637 security model is same as passthrough except the sever won't 1638 report failures if it fails to set file attributes like 1639 ownership. Security model is mandatory only for local fsdriver. 1640 Other fsdrivers (like proxy) don't take security model as a 1641 parameter. 1642 1643 ``writeout=writeout`` 1644 This is an optional argument. The only supported value is 1645 "immediate". This means that host page cache will be used to 1646 read and write data but write notification will be sent to the 1647 guest only when the data has been reported as written by the 1648 storage subsystem. 1649 1650 ``readonly=on`` 1651 Enables exporting 9p share as a readonly mount for guests. By 1652 default read-write access is given. 1653 1654 ``socket=socket`` 1655 Enables proxy filesystem driver to use passed socket file for 1656 communicating with virtfs-proxy-helper(1). Usually a helper like 1657 libvirt will create socketpair and pass one of the fds as 1658 sock\_fd. 1659 1660 ``sock_fd`` 1661 Enables proxy filesystem driver to use passed 'sock\_fd' as the 1662 socket descriptor for interfacing with virtfs-proxy-helper(1). 1663 1664 ``fmode=fmode`` 1665 Specifies the default mode for newly created files on the host. 1666 Works only with security models "mapped-xattr" and 1667 "mapped-file". 1668 1669 ``dmode=dmode`` 1670 Specifies the default mode for newly created directories on the 1671 host. Works only with security models "mapped-xattr" and 1672 "mapped-file". 1673 1674 ``mount_tag=mount_tag`` 1675 Specifies the tag name to be used by the guest to mount this 1676 export point. 1677 1678 ``multidevs=multidevs`` 1679 Specifies how to deal with multiple devices being shared with a 1680 9p export. Supported behaviours are either "remap", "forbid" or 1681 "warn". The latter is the default behaviour on which virtfs 9p 1682 expects only one device to be shared with the same export, and 1683 if more than one device is shared and accessed via the same 9p 1684 export then only a warning message is logged (once) by qemu on 1685 host side. In order to avoid file ID collisions on guest you 1686 should either create a separate virtfs export for each device to 1687 be shared with guests (recommended way) or you might use "remap" 1688 instead which allows you to share multiple devices with only one 1689 export instead, which is achieved by remapping the original 1690 inode numbers from host to guest in a way that would prevent 1691 such collisions. Remapping inodes in such use cases is required 1692 because the original device IDs from host are never passed and 1693 exposed on guest. Instead all files of an export shared with 1694 virtfs always share the same device id on guest. So two files 1695 with identical inode numbers but from actually different devices 1696 on host would otherwise cause a file ID collision and hence 1697 potential misbehaviours on guest. "forbid" on the other hand 1698 assumes like "warn" that only one device is shared by the same 1699 export, however it will not only log a warning message but also 1700 deny access to additional devices on guest. Note though that 1701 "forbid" does currently not block all possible file access 1702 operations (e.g. readdir() would still return entries from other 1703 devices). 1704ERST 1705 1706DEF("iscsi", HAS_ARG, QEMU_OPTION_iscsi, 1707 "-iscsi [user=user][,password=password]\n" 1708 " [,header-digest=CRC32C|CR32C-NONE|NONE-CRC32C|NONE\n" 1709 " [,initiator-name=initiator-iqn][,id=target-iqn]\n" 1710 " [,timeout=timeout]\n" 1711 " iSCSI session parameters\n", QEMU_ARCH_ALL) 1712 1713SRST 1714``-iscsi`` 1715 Configure iSCSI session parameters. 1716ERST 1717 1718DEFHEADING() 1719 1720DEFHEADING(USB convenience options:) 1721 1722DEF("usb", 0, QEMU_OPTION_usb, 1723 "-usb enable on-board USB host controller (if not enabled by default)\n", 1724 QEMU_ARCH_ALL) 1725SRST 1726``-usb`` 1727 Enable USB emulation on machine types with an on-board USB host 1728 controller (if not enabled by default). Note that on-board USB host 1729 controllers may not support USB 3.0. In this case 1730 ``-device qemu-xhci`` can be used instead on machines with PCI. 1731ERST 1732 1733DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice, 1734 "-usbdevice name add the host or guest USB device 'name'\n", 1735 QEMU_ARCH_ALL) 1736SRST 1737``-usbdevice devname`` 1738 Add the USB device devname, and enable an on-board USB controller 1739 if possible and necessary (just like it can be done via 1740 ``-machine usb=on``). Note that this option is mainly intended for 1741 the user's convenience only. More fine-grained control can be 1742 achieved by selecting a USB host controller (if necessary) and the 1743 desired USB device via the ``-device`` option instead. For example, 1744 instead of using ``-usbdevice mouse`` it is possible to use 1745 ``-device qemu-xhci -device usb-mouse`` to connect the USB mouse 1746 to a USB 3.0 controller instead (at least on machines that support 1747 PCI and do not have an USB controller enabled by default yet). 1748 For more details, see the chapter about 1749 :ref:`Connecting USB devices` in the System Emulation Users Guide. 1750 Possible devices for devname are: 1751 1752 ``braille`` 1753 Braille device. This will use BrlAPI to display the braille 1754 output on a real or fake device (i.e. it also creates a 1755 corresponding ``braille`` chardev automatically beside the 1756 ``usb-braille`` USB device). 1757 1758 ``keyboard`` 1759 Standard USB keyboard. Will override the PS/2 keyboard (if present). 1760 1761 ``mouse`` 1762 Virtual Mouse. This will override the PS/2 mouse emulation when 1763 activated. 1764 1765 ``tablet`` 1766 Pointer device that uses absolute coordinates (like a 1767 touchscreen). This means QEMU is able to report the mouse 1768 position without having to grab the mouse. Also overrides the 1769 PS/2 mouse emulation when activated. 1770 1771 ``wacom-tablet`` 1772 Wacom PenPartner USB tablet. 1773 1774 1775ERST 1776 1777DEFHEADING() 1778 1779DEFHEADING(Display options:) 1780 1781DEF("display", HAS_ARG, QEMU_OPTION_display, 1782#if defined(CONFIG_SPICE) 1783 "-display spice-app[,gl=on|off]\n" 1784#endif 1785#if defined(CONFIG_SDL) 1786 "-display sdl[,alt_grab=on|off][,ctrl_grab=on|off][,gl=on|core|es|off]\n" 1787 " [,show-cursor=on|off][,window-close=on|off]\n" 1788#endif 1789#if defined(CONFIG_GTK) 1790 "-display gtk[,full-screen=on|off][,gl=on|off][,grab-on-hover=on|off]\n" 1791 " [,show-cursor=on|off][,window-close=on|off]\n" 1792#endif 1793#if defined(CONFIG_VNC) 1794 "-display vnc=<display>[,<optargs>]\n" 1795#endif 1796#if defined(CONFIG_CURSES) 1797 "-display curses[,charset=<encoding>]\n" 1798#endif 1799#if defined(CONFIG_OPENGL) 1800 "-display egl-headless[,rendernode=<file>]\n" 1801#endif 1802 "-display none\n" 1803 " select display backend type\n" 1804 " The default display is equivalent to\n " 1805#if defined(CONFIG_GTK) 1806 "\"-display gtk\"\n" 1807#elif defined(CONFIG_SDL) 1808 "\"-display sdl\"\n" 1809#elif defined(CONFIG_COCOA) 1810 "\"-display cocoa\"\n" 1811#elif defined(CONFIG_VNC) 1812 "\"-vnc localhost:0,to=99,id=default\"\n" 1813#else 1814 "\"-display none\"\n" 1815#endif 1816 , QEMU_ARCH_ALL) 1817SRST 1818``-display type`` 1819 Select type of display to use. This option is a replacement for the 1820 old style -sdl/-curses/... options. Use ``-display help`` to list 1821 the available display types. Valid values for type are 1822 1823 ``spice-app[,gl=on|off]`` 1824 Start QEMU as a Spice server and launch the default Spice client 1825 application. The Spice server will redirect the serial consoles 1826 and QEMU monitors. (Since 4.0) 1827 1828 ``sdl`` 1829 Display video output via SDL (usually in a separate graphics 1830 window; see the SDL documentation for other possibilities). 1831 Valid parameters are: 1832 1833 ``alt_grab=on|off`` : Use Control+Alt+Shift-g to toggle mouse grabbing 1834 1835 ``ctrl_grab=on|off`` : Use Right-Control-g to toggle mouse grabbing 1836 1837 ``gl=on|off|core|es`` : Use OpenGL for displaying 1838 1839 ``show-cursor=on|off`` : Force showing the mouse cursor 1840 1841 ``window-close=on|off`` : Allow to quit qemu with window close button 1842 1843 ``gtk`` 1844 Display video output in a GTK window. This interface provides 1845 drop-down menus and other UI elements to configure and control 1846 the VM during runtime. Valid parameters are: 1847 1848 ``full-screen=on|off`` : Start in fullscreen mode 1849 1850 ``gl=on|off`` : Use OpenGL for displaying 1851 1852 ``grab-on-hover=on|off`` : Grab keyboard input on mouse hover 1853 1854 ``show-cursor=on|off`` : Force showing the mouse cursor 1855 1856 ``window-close=on|off`` : Allow to quit qemu with window close button 1857 1858 ``curses[,charset=<encoding>]`` 1859 Display video output via curses. For graphics device models 1860 which support a text mode, QEMU can display this output using a 1861 curses/ncurses interface. Nothing is displayed when the graphics 1862 device is in graphical mode or if the graphics device does not 1863 support a text mode. Generally only the VGA device models 1864 support text mode. The font charset used by the guest can be 1865 specified with the ``charset`` option, for example 1866 ``charset=CP850`` for IBM CP850 encoding. The default is 1867 ``CP437``. 1868 1869 ``egl-headless[,rendernode=<file>]`` 1870 Offload all OpenGL operations to a local DRI device. For any 1871 graphical display, this display needs to be paired with either 1872 VNC or SPICE displays. 1873 1874 ``vnc=<display>`` 1875 Start a VNC server on display <display> 1876 1877 ``none`` 1878 Do not display video output. The guest will still see an 1879 emulated graphics card, but its output will not be displayed to 1880 the QEMU user. This option differs from the -nographic option in 1881 that it only affects what is done with video output; -nographic 1882 also changes the destination of the serial and parallel port 1883 data. 1884ERST 1885 1886DEF("nographic", 0, QEMU_OPTION_nographic, 1887 "-nographic disable graphical output and redirect serial I/Os to console\n", 1888 QEMU_ARCH_ALL) 1889SRST 1890``-nographic`` 1891 Normally, if QEMU is compiled with graphical window support, it 1892 displays output such as guest graphics, guest console, and the QEMU 1893 monitor in a window. With this option, you can totally disable 1894 graphical output so that QEMU is a simple command line application. 1895 The emulated serial port is redirected on the console and muxed with 1896 the monitor (unless redirected elsewhere explicitly). Therefore, you 1897 can still use QEMU to debug a Linux kernel with a serial console. 1898 Use C-a h for help on switching between the console and monitor. 1899ERST 1900 1901DEF("curses", 0, QEMU_OPTION_curses, 1902 "-curses shorthand for -display curses\n", 1903 QEMU_ARCH_ALL) 1904SRST 1905``-curses`` 1906 Normally, if QEMU is compiled with graphical window support, it 1907 displays output such as guest graphics, guest console, and the QEMU 1908 monitor in a window. With this option, QEMU can display the VGA 1909 output when in text mode using a curses/ncurses interface. Nothing 1910 is displayed in graphical mode. 1911ERST 1912 1913DEF("alt-grab", 0, QEMU_OPTION_alt_grab, 1914 "-alt-grab use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt)\n", 1915 QEMU_ARCH_ALL) 1916SRST 1917``-alt-grab`` 1918 Use Ctrl-Alt-Shift to grab mouse (instead of Ctrl-Alt). Note that 1919 this also affects the special keys (for fullscreen, monitor-mode 1920 switching, etc). 1921ERST 1922 1923DEF("ctrl-grab", 0, QEMU_OPTION_ctrl_grab, 1924 "-ctrl-grab use Right-Ctrl to grab mouse (instead of Ctrl-Alt)\n", 1925 QEMU_ARCH_ALL) 1926SRST 1927``-ctrl-grab`` 1928 Use Right-Ctrl to grab mouse (instead of Ctrl-Alt). Note that this 1929 also affects the special keys (for fullscreen, monitor-mode 1930 switching, etc). 1931ERST 1932 1933DEF("no-quit", 0, QEMU_OPTION_no_quit, 1934 "-no-quit disable SDL/GTK window close capability (deprecated)\n", QEMU_ARCH_ALL) 1935SRST 1936``-no-quit`` 1937 Disable window close capability (SDL and GTK only). This option is 1938 deprecated, please use ``-display ...,window-close=off`` instead. 1939ERST 1940 1941DEF("sdl", 0, QEMU_OPTION_sdl, 1942 "-sdl shorthand for -display sdl\n", QEMU_ARCH_ALL) 1943SRST 1944``-sdl`` 1945 Enable SDL. 1946ERST 1947 1948DEF("spice", HAS_ARG, QEMU_OPTION_spice, 1949 "-spice [port=port][,tls-port=secured-port][,x509-dir=<dir>]\n" 1950 " [,x509-key-file=<file>][,x509-key-password=<file>]\n" 1951 " [,x509-cert-file=<file>][,x509-cacert-file=<file>]\n" 1952 " [,x509-dh-key-file=<file>][,addr=addr]\n" 1953 " [,ipv4=on|off][,ipv6=on|off][,unix=on|off]\n" 1954 " [,tls-ciphers=<list>]\n" 1955 " [,tls-channel=[main|display|cursor|inputs|record|playback]]\n" 1956 " [,plaintext-channel=[main|display|cursor|inputs|record|playback]]\n" 1957 " [,sasl=on|off][,disable-ticketing=on|off]\n" 1958 " [,password=<string>][,password-secret=<secret-id>]\n" 1959 " [,image-compression=[auto_glz|auto_lz|quic|glz|lz|off]]\n" 1960 " [,jpeg-wan-compression=[auto|never|always]]\n" 1961 " [,zlib-glz-wan-compression=[auto|never|always]]\n" 1962 " [,streaming-video=[off|all|filter]][,disable-copy-paste=on|off]\n" 1963 " [,disable-agent-file-xfer=on|off][,agent-mouse=[on|off]]\n" 1964 " [,playback-compression=[on|off]][,seamless-migration=[on|off]]\n" 1965 " [,gl=[on|off]][,rendernode=<file>]\n" 1966 " enable spice\n" 1967 " at least one of {port, tls-port} is mandatory\n", 1968 QEMU_ARCH_ALL) 1969SRST 1970``-spice option[,option[,...]]`` 1971 Enable the spice remote desktop protocol. Valid options are 1972 1973 ``port=<nr>`` 1974 Set the TCP port spice is listening on for plaintext channels. 1975 1976 ``addr=<addr>`` 1977 Set the IP address spice is listening on. Default is any 1978 address. 1979 1980 ``ipv4=on|off``; \ ``ipv6=on|off``; \ ``unix=on|off`` 1981 Force using the specified IP version. 1982 1983 ``password=<string>`` 1984 Set the password you need to authenticate. 1985 1986 This option is deprecated and insecure because it leaves the 1987 password visible in the process listing. Use ``password-secret`` 1988 instead. 1989 1990 ``password-secret=<secret-id>`` 1991 Set the ID of the ``secret`` object containing the password 1992 you need to authenticate. 1993 1994 ``sasl=on|off`` 1995 Require that the client use SASL to authenticate with the spice. 1996 The exact choice of authentication method used is controlled 1997 from the system / user's SASL configuration file for the 'qemu' 1998 service. This is typically found in /etc/sasl2/qemu.conf. If 1999 running QEMU as an unprivileged user, an environment variable 2000 SASL\_CONF\_PATH can be used to make it search alternate 2001 locations for the service config. While some SASL auth methods 2002 can also provide data encryption (eg GSSAPI), it is recommended 2003 that SASL always be combined with the 'tls' and 'x509' settings 2004 to enable use of SSL and server certificates. This ensures a 2005 data encryption preventing compromise of authentication 2006 credentials. 2007 2008 ``disable-ticketing=on|off`` 2009 Allow client connects without authentication. 2010 2011 ``disable-copy-paste=on|off`` 2012 Disable copy paste between the client and the guest. 2013 2014 ``disable-agent-file-xfer=on|off`` 2015 Disable spice-vdagent based file-xfer between the client and the 2016 guest. 2017 2018 ``tls-port=<nr>`` 2019 Set the TCP port spice is listening on for encrypted channels. 2020 2021 ``x509-dir=<dir>`` 2022 Set the x509 file directory. Expects same filenames as -vnc 2023 $display,x509=$dir 2024 2025 ``x509-key-file=<file>``; \ ``x509-key-password=<file>``; \ ``x509-cert-file=<file>``; \ ``x509-cacert-file=<file>``; \ ``x509-dh-key-file=<file>`` 2026 The x509 file names can also be configured individually. 2027 2028 ``tls-ciphers=<list>`` 2029 Specify which ciphers to use. 2030 2031 ``tls-channel=[main|display|cursor|inputs|record|playback]``; \ ``plaintext-channel=[main|display|cursor|inputs|record|playback]`` 2032 Force specific channel to be used with or without TLS 2033 encryption. The options can be specified multiple times to 2034 configure multiple channels. The special name "default" can be 2035 used to set the default mode. For channels which are not 2036 explicitly forced into one mode the spice client is allowed to 2037 pick tls/plaintext as he pleases. 2038 2039 ``image-compression=[auto_glz|auto_lz|quic|glz|lz|off]`` 2040 Configure image compression (lossless). Default is auto\_glz. 2041 2042 ``jpeg-wan-compression=[auto|never|always]``; \ ``zlib-glz-wan-compression=[auto|never|always]`` 2043 Configure wan image compression (lossy for slow links). Default 2044 is auto. 2045 2046 ``streaming-video=[off|all|filter]`` 2047 Configure video stream detection. Default is off. 2048 2049 ``agent-mouse=[on|off]`` 2050 Enable/disable passing mouse events via vdagent. Default is on. 2051 2052 ``playback-compression=[on|off]`` 2053 Enable/disable audio stream compression (using celt 0.5.1). 2054 Default is on. 2055 2056 ``seamless-migration=[on|off]`` 2057 Enable/disable spice seamless migration. Default is off. 2058 2059 ``gl=[on|off]`` 2060 Enable/disable OpenGL context. Default is off. 2061 2062 ``rendernode=<file>`` 2063 DRM render node for OpenGL rendering. If not specified, it will 2064 pick the first available. (Since 2.9) 2065ERST 2066 2067DEF("portrait", 0, QEMU_OPTION_portrait, 2068 "-portrait rotate graphical output 90 deg left (only PXA LCD)\n", 2069 QEMU_ARCH_ALL) 2070SRST 2071``-portrait`` 2072 Rotate graphical output 90 deg left (only PXA LCD). 2073ERST 2074 2075DEF("rotate", HAS_ARG, QEMU_OPTION_rotate, 2076 "-rotate <deg> rotate graphical output some deg left (only PXA LCD)\n", 2077 QEMU_ARCH_ALL) 2078SRST 2079``-rotate deg`` 2080 Rotate graphical output some deg left (only PXA LCD). 2081ERST 2082 2083DEF("vga", HAS_ARG, QEMU_OPTION_vga, 2084 "-vga [std|cirrus|vmware|qxl|xenfb|tcx|cg3|virtio|none]\n" 2085 " select video card type\n", QEMU_ARCH_ALL) 2086SRST 2087``-vga type`` 2088 Select type of VGA card to emulate. Valid values for type are 2089 2090 ``cirrus`` 2091 Cirrus Logic GD5446 Video card. All Windows versions starting 2092 from Windows 95 should recognize and use this graphic card. For 2093 optimal performances, use 16 bit color depth in the guest and 2094 the host OS. (This card was the default before QEMU 2.2) 2095 2096 ``std`` 2097 Standard VGA card with Bochs VBE extensions. If your guest OS 2098 supports the VESA 2.0 VBE extensions (e.g. Windows XP) and if 2099 you want to use high resolution modes (>= 1280x1024x16) then you 2100 should use this option. (This card is the default since QEMU 2101 2.2) 2102 2103 ``vmware`` 2104 VMWare SVGA-II compatible adapter. Use it if you have 2105 sufficiently recent XFree86/XOrg server or Windows guest with a 2106 driver for this card. 2107 2108 ``qxl`` 2109 QXL paravirtual graphic card. It is VGA compatible (including 2110 VESA 2.0 VBE support). Works best with qxl guest drivers 2111 installed though. Recommended choice when using the spice 2112 protocol. 2113 2114 ``tcx`` 2115 (sun4m only) Sun TCX framebuffer. This is the default 2116 framebuffer for sun4m machines and offers both 8-bit and 24-bit 2117 colour depths at a fixed resolution of 1024x768. 2118 2119 ``cg3`` 2120 (sun4m only) Sun cgthree framebuffer. This is a simple 8-bit 2121 framebuffer for sun4m machines available in both 1024x768 2122 (OpenBIOS) and 1152x900 (OBP) resolutions aimed at people 2123 wishing to run older Solaris versions. 2124 2125 ``virtio`` 2126 Virtio VGA card. 2127 2128 ``none`` 2129 Disable VGA card. 2130ERST 2131 2132DEF("full-screen", 0, QEMU_OPTION_full_screen, 2133 "-full-screen start in full screen\n", QEMU_ARCH_ALL) 2134SRST 2135``-full-screen`` 2136 Start in full screen. 2137ERST 2138 2139DEF("g", HAS_ARG, QEMU_OPTION_g , 2140 "-g WxH[xDEPTH] Set the initial graphical resolution and depth\n", 2141 QEMU_ARCH_PPC | QEMU_ARCH_SPARC | QEMU_ARCH_M68K) 2142SRST 2143``-g`` *width*\ ``x``\ *height*\ ``[x``\ *depth*\ ``]`` 2144 Set the initial graphical resolution and depth (PPC, SPARC only). 2145 2146 For PPC the default is 800x600x32. 2147 2148 For SPARC with the TCX graphics device, the default is 1024x768x8 2149 with the option of 1024x768x24. For cgthree, the default is 2150 1024x768x8 with the option of 1152x900x8 for people who wish to use 2151 OBP. 2152ERST 2153 2154DEF("vnc", HAS_ARG, QEMU_OPTION_vnc , 2155 "-vnc <display> shorthand for -display vnc=<display>\n", QEMU_ARCH_ALL) 2156SRST 2157``-vnc display[,option[,option[,...]]]`` 2158 Normally, if QEMU is compiled with graphical window support, it 2159 displays output such as guest graphics, guest console, and the QEMU 2160 monitor in a window. With this option, you can have QEMU listen on 2161 VNC display display and redirect the VGA display over the VNC 2162 session. It is very useful to enable the usb tablet device when 2163 using this option (option ``-device usb-tablet``). When using the 2164 VNC display, you must use the ``-k`` parameter to set the keyboard 2165 layout if you are not using en-us. Valid syntax for the display is 2166 2167 ``to=L`` 2168 With this option, QEMU will try next available VNC displays, 2169 until the number L, if the origianlly defined "-vnc display" is 2170 not available, e.g. port 5900+display is already used by another 2171 application. By default, to=0. 2172 2173 ``host:d`` 2174 TCP connections will only be allowed from host on display d. By 2175 convention the TCP port is 5900+d. Optionally, host can be 2176 omitted in which case the server will accept connections from 2177 any host. 2178 2179 ``unix:path`` 2180 Connections will be allowed over UNIX domain sockets where path 2181 is the location of a unix socket to listen for connections on. 2182 2183 ``none`` 2184 VNC is initialized but not started. The monitor ``change`` 2185 command can be used to later start the VNC server. 2186 2187 Following the display value there may be one or more option flags 2188 separated by commas. Valid options are 2189 2190 ``reverse=on|off`` 2191 Connect to a listening VNC client via a "reverse" connection. 2192 The client is specified by the display. For reverse network 2193 connections (host:d,``reverse``), the d argument is a TCP port 2194 number, not a display number. 2195 2196 ``websocket=on|off`` 2197 Opens an additional TCP listening port dedicated to VNC 2198 Websocket connections. If a bare websocket option is given, the 2199 Websocket port is 5700+display. An alternative port can be 2200 specified with the syntax ``websocket``\ =port. 2201 2202 If host is specified connections will only be allowed from this 2203 host. It is possible to control the websocket listen address 2204 independently, using the syntax ``websocket``\ =host:port. 2205 2206 If no TLS credentials are provided, the websocket connection 2207 runs in unencrypted mode. If TLS credentials are provided, the 2208 websocket connection requires encrypted client connections. 2209 2210 ``password=on|off`` 2211 Require that password based authentication is used for client 2212 connections. 2213 2214 The password must be set separately using the ``set_password`` 2215 command in the :ref:`QEMU monitor`. The 2216 syntax to change your password is: 2217 ``set_password <protocol> <password>`` where <protocol> could be 2218 either "vnc" or "spice". 2219 2220 If you would like to change <protocol> password expiration, you 2221 should use ``expire_password <protocol> <expiration-time>`` 2222 where expiration time could be one of the following options: 2223 now, never, +seconds or UNIX time of expiration, e.g. +60 to 2224 make password expire in 60 seconds, or 1335196800 to make 2225 password expire on "Mon Apr 23 12:00:00 EDT 2012" (UNIX time for 2226 this date and time). 2227 2228 You can also use keywords "now" or "never" for the expiration 2229 time to allow <protocol> password to expire immediately or never 2230 expire. 2231 2232 ``password-secret=<secret-id>`` 2233 Require that password based authentication is used for client 2234 connections, using the password provided by the ``secret`` 2235 object identified by ``secret-id``. 2236 2237 ``tls-creds=ID`` 2238 Provides the ID of a set of TLS credentials to use to secure the 2239 VNC server. They will apply to both the normal VNC server socket 2240 and the websocket socket (if enabled). Setting TLS credentials 2241 will cause the VNC server socket to enable the VeNCrypt auth 2242 mechanism. The credentials should have been previously created 2243 using the ``-object tls-creds`` argument. 2244 2245 ``tls-authz=ID`` 2246 Provides the ID of the QAuthZ authorization object against which 2247 the client's x509 distinguished name will validated. This object 2248 is only resolved at time of use, so can be deleted and recreated 2249 on the fly while the VNC server is active. If missing, it will 2250 default to denying access. 2251 2252 ``sasl=on|off`` 2253 Require that the client use SASL to authenticate with the VNC 2254 server. The exact choice of authentication method used is 2255 controlled from the system / user's SASL configuration file for 2256 the 'qemu' service. This is typically found in 2257 /etc/sasl2/qemu.conf. If running QEMU as an unprivileged user, 2258 an environment variable SASL\_CONF\_PATH can be used to make it 2259 search alternate locations for the service config. While some 2260 SASL auth methods can also provide data encryption (eg GSSAPI), 2261 it is recommended that SASL always be combined with the 'tls' 2262 and 'x509' settings to enable use of SSL and server 2263 certificates. This ensures a data encryption preventing 2264 compromise of authentication credentials. See the 2265 :ref:`VNC security` section in the System Emulation Users Guide 2266 for details on using SASL authentication. 2267 2268 ``sasl-authz=ID`` 2269 Provides the ID of the QAuthZ authorization object against which 2270 the client's SASL username will validated. This object is only 2271 resolved at time of use, so can be deleted and recreated on the 2272 fly while the VNC server is active. If missing, it will default 2273 to denying access. 2274 2275 ``acl=on|off`` 2276 Legacy method for enabling authorization of clients against the 2277 x509 distinguished name and SASL username. It results in the 2278 creation of two ``authz-list`` objects with IDs of 2279 ``vnc.username`` and ``vnc.x509dname``. The rules for these 2280 objects must be configured with the HMP ACL commands. 2281 2282 This option is deprecated and should no longer be used. The new 2283 ``sasl-authz`` and ``tls-authz`` options are a replacement. 2284 2285 ``lossy=on|off`` 2286 Enable lossy compression methods (gradient, JPEG, ...). If this 2287 option is set, VNC client may receive lossy framebuffer updates 2288 depending on its encoding settings. Enabling this option can 2289 save a lot of bandwidth at the expense of quality. 2290 2291 ``non-adaptive=on|off`` 2292 Disable adaptive encodings. Adaptive encodings are enabled by 2293 default. An adaptive encoding will try to detect frequently 2294 updated screen regions, and send updates in these regions using 2295 a lossy encoding (like JPEG). This can be really helpful to save 2296 bandwidth when playing videos. Disabling adaptive encodings 2297 restores the original static behavior of encodings like Tight. 2298 2299 ``share=[allow-exclusive|force-shared|ignore]`` 2300 Set display sharing policy. 'allow-exclusive' allows clients to 2301 ask for exclusive access. As suggested by the rfb spec this is 2302 implemented by dropping other connections. Connecting multiple 2303 clients in parallel requires all clients asking for a shared 2304 session (vncviewer: -shared switch). This is the default. 2305 'force-shared' disables exclusive client access. Useful for 2306 shared desktop sessions, where you don't want someone forgetting 2307 specify -shared disconnect everybody else. 'ignore' completely 2308 ignores the shared flag and allows everybody connect 2309 unconditionally. Doesn't conform to the rfb spec but is 2310 traditional QEMU behavior. 2311 2312 ``key-delay-ms`` 2313 Set keyboard delay, for key down and key up events, in 2314 milliseconds. Default is 10. Keyboards are low-bandwidth 2315 devices, so this slowdown can help the device and guest to keep 2316 up and not lose events in case events are arriving in bulk. 2317 Possible causes for the latter are flaky network connections, or 2318 scripts for automated testing. 2319 2320 ``audiodev=audiodev`` 2321 Use the specified audiodev when the VNC client requests audio 2322 transmission. When not using an -audiodev argument, this option 2323 must be omitted, otherwise is must be present and specify a 2324 valid audiodev. 2325 2326 ``power-control=on|off`` 2327 Permit the remote client to issue shutdown, reboot or reset power 2328 control requests. 2329ERST 2330 2331ARCHHEADING(, QEMU_ARCH_I386) 2332 2333ARCHHEADING(i386 target only:, QEMU_ARCH_I386) 2334 2335DEF("win2k-hack", 0, QEMU_OPTION_win2k_hack, 2336 "-win2k-hack use it when installing Windows 2000 to avoid a disk full bug\n", 2337 QEMU_ARCH_I386) 2338SRST 2339``-win2k-hack`` 2340 Use it when installing Windows 2000 to avoid a disk full bug. After 2341 Windows 2000 is installed, you no longer need this option (this 2342 option slows down the IDE transfers). 2343ERST 2344 2345DEF("no-fd-bootchk", 0, QEMU_OPTION_no_fd_bootchk, 2346 "-no-fd-bootchk disable boot signature checking for floppy disks\n", 2347 QEMU_ARCH_I386) 2348SRST 2349``-no-fd-bootchk`` 2350 Disable boot signature checking for floppy disks in BIOS. May be 2351 needed to boot from old floppy disks. 2352ERST 2353 2354DEF("no-acpi", 0, QEMU_OPTION_no_acpi, 2355 "-no-acpi disable ACPI\n", QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2356SRST 2357``-no-acpi`` 2358 Disable ACPI (Advanced Configuration and Power Interface) support. 2359 Use it if your guest OS complains about ACPI problems (PC target 2360 machine only). 2361ERST 2362 2363DEF("no-hpet", 0, QEMU_OPTION_no_hpet, 2364 "-no-hpet disable HPET\n", QEMU_ARCH_I386) 2365SRST 2366``-no-hpet`` 2367 Disable HPET support. 2368ERST 2369 2370DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable, 2371 "-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" 2372 " ACPI table description\n", QEMU_ARCH_I386) 2373SRST 2374``-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]...]`` 2375 Add ACPI table with specified header fields and context from 2376 specified files. For file=, take whole ACPI table from the specified 2377 files, including all ACPI headers (possible overridden by other 2378 options). For data=, only data portion of the table is used, all 2379 header information is specified in the command line. If a SLIC table 2380 is supplied to QEMU, then the SLIC's oem\_id and oem\_table\_id 2381 fields will override the same in the RSDT and the FADT (a.k.a. 2382 FACP), in order to ensure the field matches required by the 2383 Microsoft SLIC spec and the ACPI spec. 2384ERST 2385 2386DEF("smbios", HAS_ARG, QEMU_OPTION_smbios, 2387 "-smbios file=binary\n" 2388 " load SMBIOS entry from binary file\n" 2389 "-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d]\n" 2390 " [,uefi=on|off]\n" 2391 " specify SMBIOS type 0 fields\n" 2392 "-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2393 " [,uuid=uuid][,sku=str][,family=str]\n" 2394 " specify SMBIOS type 1 fields\n" 2395 "-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str]\n" 2396 " [,asset=str][,location=str]\n" 2397 " specify SMBIOS type 2 fields\n" 2398 "-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str]\n" 2399 " [,sku=str]\n" 2400 " specify SMBIOS type 3 fields\n" 2401 "-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str]\n" 2402 " [,asset=str][,part=str][,max-speed=%d][,current-speed=%d]\n" 2403 " specify SMBIOS type 4 fields\n" 2404 "-smbios type=11[,value=str][,path=filename]\n" 2405 " specify SMBIOS type 11 fields\n" 2406 "-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str]\n" 2407 " [,asset=str][,part=str][,speed=%d]\n" 2408 " specify SMBIOS type 17 fields\n" 2409 "-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]\n" 2410 " specify SMBIOS type 41 fields\n", 2411 QEMU_ARCH_I386 | QEMU_ARCH_ARM) 2412SRST 2413``-smbios file=binary`` 2414 Load SMBIOS entry from binary file. 2415 2416``-smbios type=0[,vendor=str][,version=str][,date=str][,release=%d.%d][,uefi=on|off]`` 2417 Specify SMBIOS type 0 fields 2418 2419``-smbios type=1[,manufacturer=str][,product=str][,version=str][,serial=str][,uuid=uuid][,sku=str][,family=str]`` 2420 Specify SMBIOS type 1 fields 2421 2422``-smbios type=2[,manufacturer=str][,product=str][,version=str][,serial=str][,asset=str][,location=str]`` 2423 Specify SMBIOS type 2 fields 2424 2425``-smbios type=3[,manufacturer=str][,version=str][,serial=str][,asset=str][,sku=str]`` 2426 Specify SMBIOS type 3 fields 2427 2428``-smbios type=4[,sock_pfx=str][,manufacturer=str][,version=str][,serial=str][,asset=str][,part=str]`` 2429 Specify SMBIOS type 4 fields 2430 2431``-smbios type=11[,value=str][,path=filename]`` 2432 Specify SMBIOS type 11 fields 2433 2434 This argument can be repeated multiple times, and values are added in the order they are parsed. 2435 Applications intending to use OEM strings data are encouraged to use their application name as 2436 a prefix for the value string. This facilitates passing information for multiple applications 2437 concurrently. 2438 2439 The ``value=str`` syntax provides the string data inline, while the ``path=filename`` syntax 2440 loads data from a file on disk. Note that the file is not permitted to contain any NUL bytes. 2441 2442 Both the ``value`` and ``path`` options can be repeated multiple times and will be added to 2443 the SMBIOS table in the order in which they appear. 2444 2445 Note that on the x86 architecture, the total size of all SMBIOS tables is limited to 65535 2446 bytes. Thus the OEM strings data is not suitable for passing large amounts of data into the 2447 guest. Instead it should be used as a indicator to inform the guest where to locate the real 2448 data set, for example, by specifying the serial ID of a block device. 2449 2450 An example passing three strings is 2451 2452 .. parsed-literal:: 2453 2454 -smbios type=11,value=cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/,\\ 2455 value=anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os,\\ 2456 path=/some/file/with/oemstringsdata.txt 2457 2458 In the guest OS this is visible with the ``dmidecode`` command 2459 2460 .. parsed-literal:: 2461 2462 $ dmidecode -t 11 2463 Handle 0x0E00, DMI type 11, 5 bytes 2464 OEM Strings 2465 String 1: cloud-init:ds=nocloud-net;s=http://10.10.0.1:8000/ 2466 String 2: anaconda:method=http://dl.fedoraproject.org/pub/fedora/linux/releases/25/x86_64/os 2467 String 3: myapp:some extra data 2468 2469 2470``-smbios type=17[,loc_pfx=str][,bank=str][,manufacturer=str][,serial=str][,asset=str][,part=str][,speed=%d]`` 2471 Specify SMBIOS type 17 fields 2472 2473``-smbios type=41[,designation=str][,kind=str][,instance=%d][,pcidev=str]`` 2474 Specify SMBIOS type 41 fields 2475 2476 This argument can be repeated multiple times. Its main use is to allow network interfaces be created 2477 as ``enoX`` on Linux, with X being the instance number, instead of the name depending on the interface 2478 position on the PCI bus. 2479 2480 Here is an example of use: 2481 2482 .. parsed-literal:: 2483 2484 -netdev user,id=internet \\ 2485 -device virtio-net-pci,mac=50:54:00:00:00:42,netdev=internet,id=internet-dev \\ 2486 -smbios type=41,designation='Onboard LAN',instance=1,kind=ethernet,pcidev=internet-dev 2487 2488 In the guest OS, the device should then appear as ``eno1``: 2489 2490 ..parsed-literal:: 2491 2492 $ ip -brief l 2493 lo UNKNOWN 00:00:00:00:00:00 <LOOPBACK,UP,LOWER_UP> 2494 eno1 UP 50:54:00:00:00:42 <BROADCAST,MULTICAST,UP,LOWER_UP> 2495 2496 Currently, the PCI device has to be attached to the root bus. 2497 2498ERST 2499 2500DEFHEADING() 2501 2502DEFHEADING(Network options:) 2503 2504DEF("netdev", HAS_ARG, QEMU_OPTION_netdev, 2505#ifdef CONFIG_SLIRP 2506 "-netdev user,id=str[,ipv4=on|off][,net=addr[/mask]][,host=addr]\n" 2507 " [,ipv6=on|off][,ipv6-net=addr[/int]][,ipv6-host=addr]\n" 2508 " [,restrict=on|off][,hostname=host][,dhcpstart=addr]\n" 2509 " [,dns=addr][,ipv6-dns=addr][,dnssearch=domain][,domainname=domain]\n" 2510 " [,tftp=dir][,tftp-server-name=name][,bootfile=f][,hostfwd=rule][,guestfwd=rule]" 2511#ifndef _WIN32 2512 "[,smb=dir[,smbserver=addr]]\n" 2513#endif 2514 " configure a user mode network backend with ID 'str',\n" 2515 " its DHCP server and optional services\n" 2516#endif 2517#ifdef _WIN32 2518 "-netdev tap,id=str,ifname=name\n" 2519 " configure a host TAP network backend with ID 'str'\n" 2520#else 2521 "-netdev tap,id=str[,fd=h][,fds=x:y:...:z][,ifname=name][,script=file][,downscript=dfile]\n" 2522 " [,br=bridge][,helper=helper][,sndbuf=nbytes][,vnet_hdr=on|off][,vhost=on|off]\n" 2523 " [,vhostfd=h][,vhostfds=x:y:...:z][,vhostforce=on|off][,queues=n]\n" 2524 " [,poll-us=n]\n" 2525 " configure a host TAP network backend with ID 'str'\n" 2526 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2527 " use network scripts 'file' (default=" DEFAULT_NETWORK_SCRIPT ")\n" 2528 " to configure it and 'dfile' (default=" DEFAULT_NETWORK_DOWN_SCRIPT ")\n" 2529 " to deconfigure it\n" 2530 " use '[down]script=no' to disable script execution\n" 2531 " use network helper 'helper' (default=" DEFAULT_BRIDGE_HELPER ") to\n" 2532 " configure it\n" 2533 " use 'fd=h' to connect to an already opened TAP interface\n" 2534 " use 'fds=x:y:...:z' to connect to already opened multiqueue capable TAP interfaces\n" 2535 " use 'sndbuf=nbytes' to limit the size of the send buffer (the\n" 2536 " default is disabled 'sndbuf=0' to enable flow control set 'sndbuf=1048576')\n" 2537 " use vnet_hdr=off to avoid enabling the IFF_VNET_HDR tap flag\n" 2538 " use vnet_hdr=on to make the lack of IFF_VNET_HDR support an error condition\n" 2539 " use vhost=on to enable experimental in kernel accelerator\n" 2540 " (only has effect for virtio guests which use MSIX)\n" 2541 " use vhostforce=on to force vhost on for non-MSIX virtio guests\n" 2542 " use 'vhostfd=h' to connect to an already opened vhost net device\n" 2543 " use 'vhostfds=x:y:...:z to connect to multiple already opened vhost net devices\n" 2544 " use 'queues=n' to specify the number of queues to be created for multiqueue TAP\n" 2545 " use 'poll-us=n' to specify the maximum number of microseconds that could be\n" 2546 " spent on busy polling for vhost net\n" 2547 "-netdev bridge,id=str[,br=bridge][,helper=helper]\n" 2548 " configure a host TAP network backend with ID 'str' that is\n" 2549 " connected to a bridge (default=" DEFAULT_BRIDGE_INTERFACE ")\n" 2550 " using the program 'helper (default=" DEFAULT_BRIDGE_HELPER ")\n" 2551#endif 2552#ifdef __linux__ 2553 "-netdev l2tpv3,id=str,src=srcaddr,dst=dstaddr[,srcport=srcport][,dstport=dstport]\n" 2554 " [,rxsession=rxsession],txsession=txsession[,ipv6=on|off][,udp=on|off]\n" 2555 " [,cookie64=on|off][,counter][,pincounter][,txcookie=txcookie]\n" 2556 " [,rxcookie=rxcookie][,offset=offset]\n" 2557 " configure a network backend with ID 'str' connected to\n" 2558 " an Ethernet over L2TPv3 pseudowire.\n" 2559 " Linux kernel 3.3+ as well as most routers can talk\n" 2560 " L2TPv3. This transport allows connecting a VM to a VM,\n" 2561 " VM to a router and even VM to Host. It is a nearly-universal\n" 2562 " standard (RFC3931). Note - this implementation uses static\n" 2563 " pre-configured tunnels (same as the Linux kernel).\n" 2564 " use 'src=' to specify source address\n" 2565 " use 'dst=' to specify destination address\n" 2566 " use 'udp=on' to specify udp encapsulation\n" 2567 " use 'srcport=' to specify source udp port\n" 2568 " use 'dstport=' to specify destination udp port\n" 2569 " use 'ipv6=on' to force v6\n" 2570 " L2TPv3 uses cookies to prevent misconfiguration as\n" 2571 " well as a weak security measure\n" 2572 " use 'rxcookie=0x012345678' to specify a rxcookie\n" 2573 " use 'txcookie=0x012345678' to specify a txcookie\n" 2574 " use 'cookie64=on' to set cookie size to 64 bit, otherwise 32\n" 2575 " use 'counter=off' to force a 'cut-down' L2TPv3 with no counter\n" 2576 " use 'pincounter=on' to work around broken counter handling in peer\n" 2577 " use 'offset=X' to add an extra offset between header and data\n" 2578#endif 2579 "-netdev socket,id=str[,fd=h][,listen=[host]:port][,connect=host:port]\n" 2580 " configure a network backend to connect to another network\n" 2581 " using a socket connection\n" 2582 "-netdev socket,id=str[,fd=h][,mcast=maddr:port[,localaddr=addr]]\n" 2583 " configure a network backend to connect to a multicast maddr and port\n" 2584 " use 'localaddr=addr' to specify the host address to send packets from\n" 2585 "-netdev socket,id=str[,fd=h][,udp=host:port][,localaddr=host:port]\n" 2586 " configure a network backend to connect to another network\n" 2587 " using an UDP tunnel\n" 2588#ifdef CONFIG_VDE 2589 "-netdev vde,id=str[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]\n" 2590 " configure a network backend to connect to port 'n' of a vde switch\n" 2591 " running on host and listening for incoming connections on 'socketpath'.\n" 2592 " Use group 'groupname' and mode 'octalmode' to change default\n" 2593 " ownership and permissions for communication port.\n" 2594#endif 2595#ifdef CONFIG_NETMAP 2596 "-netdev netmap,id=str,ifname=name[,devname=nmname]\n" 2597 " attach to the existing netmap-enabled network interface 'name', or to a\n" 2598 " VALE port (created on the fly) called 'name' ('nmname' is name of the \n" 2599 " netmap device, defaults to '/dev/netmap')\n" 2600#endif 2601#ifdef CONFIG_POSIX 2602 "-netdev vhost-user,id=str,chardev=dev[,vhostforce=on|off]\n" 2603 " configure a vhost-user network, backed by a chardev 'dev'\n" 2604#endif 2605#ifdef __linux__ 2606 "-netdev vhost-vdpa,id=str,vhostdev=/path/to/dev\n" 2607 " configure a vhost-vdpa network,Establish a vhost-vdpa netdev\n" 2608#endif 2609 "-netdev hubport,id=str,hubid=n[,netdev=nd]\n" 2610 " configure a hub port on the hub with ID 'n'\n", QEMU_ARCH_ALL) 2611DEF("nic", HAS_ARG, QEMU_OPTION_nic, 2612 "-nic [tap|bridge|" 2613#ifdef CONFIG_SLIRP 2614 "user|" 2615#endif 2616#ifdef __linux__ 2617 "l2tpv3|" 2618#endif 2619#ifdef CONFIG_VDE 2620 "vde|" 2621#endif 2622#ifdef CONFIG_NETMAP 2623 "netmap|" 2624#endif 2625#ifdef CONFIG_POSIX 2626 "vhost-user|" 2627#endif 2628 "socket][,option][,...][mac=macaddr]\n" 2629 " initialize an on-board / default host NIC (using MAC address\n" 2630 " macaddr) and connect it to the given host network backend\n" 2631 "-nic none use it alone to have zero network devices (the default is to\n" 2632 " provided a 'user' network connection)\n", 2633 QEMU_ARCH_ALL) 2634DEF("net", HAS_ARG, QEMU_OPTION_net, 2635 "-net nic[,macaddr=mac][,model=type][,name=str][,addr=str][,vectors=v]\n" 2636 " configure or create an on-board (or machine default) NIC and\n" 2637 " connect it to hub 0 (please use -nic unless you need a hub)\n" 2638 "-net [" 2639#ifdef CONFIG_SLIRP 2640 "user|" 2641#endif 2642 "tap|" 2643 "bridge|" 2644#ifdef CONFIG_VDE 2645 "vde|" 2646#endif 2647#ifdef CONFIG_NETMAP 2648 "netmap|" 2649#endif 2650 "socket][,option][,option][,...]\n" 2651 " old way to initialize a host network interface\n" 2652 " (use the -netdev option if possible instead)\n", QEMU_ARCH_ALL) 2653SRST 2654``-nic [tap|bridge|user|l2tpv3|vde|netmap|vhost-user|socket][,...][,mac=macaddr][,model=mn]`` 2655 This option is a shortcut for configuring both the on-board 2656 (default) guest NIC hardware and the host network backend in one go. 2657 The host backend options are the same as with the corresponding 2658 ``-netdev`` options below. The guest NIC model can be set with 2659 ``model=modelname``. Use ``model=help`` to list the available device 2660 types. The hardware MAC address can be set with ``mac=macaddr``. 2661 2662 The following two example do exactly the same, to show how ``-nic`` 2663 can be used to shorten the command line length: 2664 2665 .. parsed-literal:: 2666 2667 |qemu_system| -netdev user,id=n1,ipv6=off -device e1000,netdev=n1,mac=52:54:98:76:54:32 2668 |qemu_system| -nic user,ipv6=off,model=e1000,mac=52:54:98:76:54:32 2669 2670``-nic none`` 2671 Indicate that no network devices should be configured. It is used to 2672 override the default configuration (default NIC with "user" host 2673 network backend) which is activated if no other networking options 2674 are provided. 2675 2676``-netdev user,id=id[,option][,option][,...]`` 2677 Configure user mode host network backend which requires no 2678 administrator privilege to run. Valid options are: 2679 2680 ``id=id`` 2681 Assign symbolic name for use in monitor commands. 2682 2683 ``ipv4=on|off and ipv6=on|off`` 2684 Specify that either IPv4 or IPv6 must be enabled. If neither is 2685 specified both protocols are enabled. 2686 2687 ``net=addr[/mask]`` 2688 Set IP network address the guest will see. Optionally specify 2689 the netmask, either in the form a.b.c.d or as number of valid 2690 top-most bits. Default is 10.0.2.0/24. 2691 2692 ``host=addr`` 2693 Specify the guest-visible address of the host. Default is the 2694 2nd IP in the guest network, i.e. x.x.x.2. 2695 2696 ``ipv6-net=addr[/int]`` 2697 Set IPv6 network address the guest will see (default is 2698 fec0::/64). The network prefix is given in the usual hexadecimal 2699 IPv6 address notation. The prefix size is optional, and is given 2700 as the number of valid top-most bits (default is 64). 2701 2702 ``ipv6-host=addr`` 2703 Specify the guest-visible IPv6 address of the host. Default is 2704 the 2nd IPv6 in the guest network, i.e. xxxx::2. 2705 2706 ``restrict=on|off`` 2707 If this option is enabled, the guest will be isolated, i.e. it 2708 will not be able to contact the host and no guest IP packets 2709 will be routed over the host to the outside. This option does 2710 not affect any explicitly set forwarding rules. 2711 2712 ``hostname=name`` 2713 Specifies the client hostname reported by the built-in DHCP 2714 server. 2715 2716 ``dhcpstart=addr`` 2717 Specify the first of the 16 IPs the built-in DHCP server can 2718 assign. Default is the 15th to 31st IP in the guest network, 2719 i.e. x.x.x.15 to x.x.x.31. 2720 2721 ``dns=addr`` 2722 Specify the guest-visible address of the virtual nameserver. The 2723 address must be different from the host address. Default is the 2724 3rd IP in the guest network, i.e. x.x.x.3. 2725 2726 ``ipv6-dns=addr`` 2727 Specify the guest-visible address of the IPv6 virtual 2728 nameserver. The address must be different from the host address. 2729 Default is the 3rd IP in the guest network, i.e. xxxx::3. 2730 2731 ``dnssearch=domain`` 2732 Provides an entry for the domain-search list sent by the 2733 built-in DHCP server. More than one domain suffix can be 2734 transmitted by specifying this option multiple times. If 2735 supported, this will cause the guest to automatically try to 2736 append the given domain suffix(es) in case a domain name can not 2737 be resolved. 2738 2739 Example: 2740 2741 .. parsed-literal:: 2742 2743 |qemu_system| -nic user,dnssearch=mgmt.example.org,dnssearch=example.org 2744 2745 ``domainname=domain`` 2746 Specifies the client domain name reported by the built-in DHCP 2747 server. 2748 2749 ``tftp=dir`` 2750 When using the user mode network stack, activate a built-in TFTP 2751 server. The files in dir will be exposed as the root of a TFTP 2752 server. The TFTP client on the guest must be configured in 2753 binary mode (use the command ``bin`` of the Unix TFTP client). 2754 2755 ``tftp-server-name=name`` 2756 In BOOTP reply, broadcast name as the "TFTP server name" 2757 (RFC2132 option 66). This can be used to advise the guest to 2758 load boot files or configurations from a different server than 2759 the host address. 2760 2761 ``bootfile=file`` 2762 When using the user mode network stack, broadcast file as the 2763 BOOTP filename. In conjunction with ``tftp``, this can be used 2764 to network boot a guest from a local directory. 2765 2766 Example (using pxelinux): 2767 2768 .. parsed-literal:: 2769 2770 |qemu_system| -hda linux.img -boot n -device e1000,netdev=n1 \\ 2771 -netdev user,id=n1,tftp=/path/to/tftp/files,bootfile=/pxelinux.0 2772 2773 ``smb=dir[,smbserver=addr]`` 2774 When using the user mode network stack, activate a built-in SMB 2775 server so that Windows OSes can access to the host files in 2776 ``dir`` transparently. The IP address of the SMB server can be 2777 set to addr. By default the 4th IP in the guest network is used, 2778 i.e. x.x.x.4. 2779 2780 In the guest Windows OS, the line: 2781 2782 :: 2783 2784 10.0.2.4 smbserver 2785 2786 must be added in the file ``C:\WINDOWS\LMHOSTS`` (for windows 2787 9x/Me) or ``C:\WINNT\SYSTEM32\DRIVERS\ETC\LMHOSTS`` (Windows 2788 NT/2000). 2789 2790 Then ``dir`` can be accessed in ``\\smbserver\qemu``. 2791 2792 Note that a SAMBA server must be installed on the host OS. 2793 2794 ``hostfwd=[tcp|udp]:[hostaddr]:hostport-[guestaddr]:guestport`` 2795 Redirect incoming TCP or UDP connections to the host port 2796 hostport to the guest IP address guestaddr on guest port 2797 guestport. If guestaddr is not specified, its value is x.x.x.15 2798 (default first address given by the built-in DHCP server). By 2799 specifying hostaddr, the rule can be bound to a specific host 2800 interface. If no connection type is set, TCP is used. This 2801 option can be given multiple times. 2802 2803 For example, to redirect host X11 connection from screen 1 to 2804 guest screen 0, use the following: 2805 2806 .. parsed-literal:: 2807 2808 # on the host 2809 |qemu_system| -nic user,hostfwd=tcp:127.0.0.1:6001-:6000 2810 # this host xterm should open in the guest X11 server 2811 xterm -display :1 2812 2813 To redirect telnet connections from host port 5555 to telnet 2814 port on the guest, use the following: 2815 2816 .. parsed-literal:: 2817 2818 # on the host 2819 |qemu_system| -nic user,hostfwd=tcp::5555-:23 2820 telnet localhost 5555 2821 2822 Then when you use on the host ``telnet localhost 5555``, you 2823 connect to the guest telnet server. 2824 2825 ``guestfwd=[tcp]:server:port-dev``; \ ``guestfwd=[tcp]:server:port-cmd:command`` 2826 Forward guest TCP connections to the IP address server on port 2827 port to the character device dev or to a program executed by 2828 cmd:command which gets spawned for each connection. This option 2829 can be given multiple times. 2830 2831 You can either use a chardev directly and have that one used 2832 throughout QEMU's lifetime, like in the following example: 2833 2834 .. parsed-literal:: 2835 2836 # open 10.10.1.1:4321 on bootup, connect 10.0.2.100:1234 to it whenever 2837 # the guest accesses it 2838 |qemu_system| -nic user,guestfwd=tcp:10.0.2.100:1234-tcp:10.10.1.1:4321 2839 2840 Or you can execute a command on every TCP connection established 2841 by the guest, so that QEMU behaves similar to an inetd process 2842 for that virtual server: 2843 2844 .. parsed-literal:: 2845 2846 # call "netcat 10.10.1.1 4321" on every TCP connection to 10.0.2.100:1234 2847 # and connect the TCP stream to its stdin/stdout 2848 |qemu_system| -nic 'user,id=n1,guestfwd=tcp:10.0.2.100:1234-cmd:netcat 10.10.1.1 4321' 2849 2850``-netdev tap,id=id[,fd=h][,ifname=name][,script=file][,downscript=dfile][,br=bridge][,helper=helper]`` 2851 Configure a host TAP network backend with ID id. 2852 2853 Use the network script file to configure it and the network script 2854 dfile to deconfigure it. If name is not provided, the OS 2855 automatically provides one. The default network configure script is 2856 ``/etc/qemu-ifup`` and the default network deconfigure script is 2857 ``/etc/qemu-ifdown``. Use ``script=no`` or ``downscript=no`` to 2858 disable script execution. 2859 2860 If running QEMU as an unprivileged user, use the network helper 2861 to configure the TAP interface and attach it to the bridge. 2862 The default network helper executable is 2863 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2864 ``br0``. 2865 2866 ``fd``\ =h can be used to specify the handle of an already opened 2867 host TAP interface. 2868 2869 Examples: 2870 2871 .. parsed-literal:: 2872 2873 #launch a QEMU instance with the default network script 2874 |qemu_system| linux.img -nic tap 2875 2876 .. parsed-literal:: 2877 2878 #launch a QEMU instance with two NICs, each one connected 2879 #to a TAP device 2880 |qemu_system| linux.img \\ 2881 -netdev tap,id=nd0,ifname=tap0 -device e1000,netdev=nd0 \\ 2882 -netdev tap,id=nd1,ifname=tap1 -device rtl8139,netdev=nd1 2883 2884 .. parsed-literal:: 2885 2886 #launch a QEMU instance with the default network helper to 2887 #connect a TAP device to bridge br0 2888 |qemu_system| linux.img -device virtio-net-pci,netdev=n1 \\ 2889 -netdev tap,id=n1,"helper=/path/to/qemu-bridge-helper" 2890 2891``-netdev bridge,id=id[,br=bridge][,helper=helper]`` 2892 Connect a host TAP network interface to a host bridge device. 2893 2894 Use the network helper helper to configure the TAP interface and 2895 attach it to the bridge. The default network helper executable is 2896 ``/path/to/qemu-bridge-helper`` and the default bridge device is 2897 ``br0``. 2898 2899 Examples: 2900 2901 .. parsed-literal:: 2902 2903 #launch a QEMU instance with the default network helper to 2904 #connect a TAP device to bridge br0 2905 |qemu_system| linux.img -netdev bridge,id=n1 -device virtio-net,netdev=n1 2906 2907 .. parsed-literal:: 2908 2909 #launch a QEMU instance with the default network helper to 2910 #connect a TAP device to bridge qemubr0 2911 |qemu_system| linux.img -netdev bridge,br=qemubr0,id=n1 -device virtio-net,netdev=n1 2912 2913``-netdev socket,id=id[,fd=h][,listen=[host]:port][,connect=host:port]`` 2914 This host network backend can be used to connect the guest's network 2915 to another QEMU virtual machine using a TCP socket connection. If 2916 ``listen`` is specified, QEMU waits for incoming connections on port 2917 (host is optional). ``connect`` is used to connect to another QEMU 2918 instance using the ``listen`` option. ``fd``\ =h specifies an 2919 already opened TCP socket. 2920 2921 Example: 2922 2923 .. parsed-literal:: 2924 2925 # launch a first QEMU instance 2926 |qemu_system| linux.img \\ 2927 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2928 -netdev socket,id=n1,listen=:1234 2929 # connect the network of this instance to the network of the first instance 2930 |qemu_system| linux.img \\ 2931 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 2932 -netdev socket,id=n2,connect=127.0.0.1:1234 2933 2934``-netdev socket,id=id[,fd=h][,mcast=maddr:port[,localaddr=addr]]`` 2935 Configure a socket host network backend to share the guest's network 2936 traffic with another QEMU virtual machines using a UDP multicast 2937 socket, effectively making a bus for every QEMU with same multicast 2938 address maddr and port. NOTES: 2939 2940 1. Several QEMU can be running on different hosts and share same bus 2941 (assuming correct multicast setup for these hosts). 2942 2943 2. mcast support is compatible with User Mode Linux (argument 2944 ``ethN=mcast``), see http://user-mode-linux.sf.net. 2945 2946 3. Use ``fd=h`` to specify an already opened UDP multicast socket. 2947 2948 Example: 2949 2950 .. parsed-literal:: 2951 2952 # launch one QEMU instance 2953 |qemu_system| linux.img \\ 2954 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2955 -netdev socket,id=n1,mcast=230.0.0.1:1234 2956 # launch another QEMU instance on same "bus" 2957 |qemu_system| linux.img \\ 2958 -device e1000,netdev=n2,mac=52:54:00:12:34:57 \\ 2959 -netdev socket,id=n2,mcast=230.0.0.1:1234 2960 # launch yet another QEMU instance on same "bus" 2961 |qemu_system| linux.img \\ 2962 -device e1000,netdev=n3,mac=52:54:00:12:34:58 \\ 2963 -netdev socket,id=n3,mcast=230.0.0.1:1234 2964 2965 Example (User Mode Linux compat.): 2966 2967 .. parsed-literal:: 2968 2969 # launch QEMU instance (note mcast address selected is UML's default) 2970 |qemu_system| linux.img \\ 2971 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2972 -netdev socket,id=n1,mcast=239.192.168.1:1102 2973 # launch UML 2974 /path/to/linux ubd0=/path/to/root_fs eth0=mcast 2975 2976 Example (send packets from host's 1.2.3.4): 2977 2978 .. parsed-literal:: 2979 2980 |qemu_system| linux.img \\ 2981 -device e1000,netdev=n1,mac=52:54:00:12:34:56 \\ 2982 -netdev socket,id=n1,mcast=239.192.168.1:1102,localaddr=1.2.3.4 2983 2984``-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]`` 2985 Configure a L2TPv3 pseudowire host network backend. L2TPv3 (RFC3931) 2986 is a popular protocol to transport Ethernet (and other Layer 2) data 2987 frames between two systems. It is present in routers, firewalls and 2988 the Linux kernel (from version 3.3 onwards). 2989 2990 This transport allows a VM to communicate to another VM, router or 2991 firewall directly. 2992 2993 ``src=srcaddr`` 2994 source address (mandatory) 2995 2996 ``dst=dstaddr`` 2997 destination address (mandatory) 2998 2999 ``udp`` 3000 select udp encapsulation (default is ip). 3001 3002 ``srcport=srcport`` 3003 source udp port. 3004 3005 ``dstport=dstport`` 3006 destination udp port. 3007 3008 ``ipv6`` 3009 force v6, otherwise defaults to v4. 3010 3011 ``rxcookie=rxcookie``; \ ``txcookie=txcookie`` 3012 Cookies are a weak form of security in the l2tpv3 specification. 3013 Their function is mostly to prevent misconfiguration. By default 3014 they are 32 bit. 3015 3016 ``cookie64`` 3017 Set cookie size to 64 bit instead of the default 32 3018 3019 ``counter=off`` 3020 Force a 'cut-down' L2TPv3 with no counter as in 3021 draft-mkonstan-l2tpext-keyed-ipv6-tunnel-00 3022 3023 ``pincounter=on`` 3024 Work around broken counter handling in peer. This may also help 3025 on networks which have packet reorder. 3026 3027 ``offset=offset`` 3028 Add an extra offset between header and data 3029 3030 For example, to attach a VM running on host 4.3.2.1 via L2TPv3 to 3031 the bridge br-lan on the remote Linux host 1.2.3.4: 3032 3033 .. parsed-literal:: 3034 3035 # Setup tunnel on linux host using raw ip as encapsulation 3036 # on 1.2.3.4 3037 ip l2tp add tunnel remote 4.3.2.1 local 1.2.3.4 tunnel_id 1 peer_tunnel_id 1 \\ 3038 encap udp udp_sport 16384 udp_dport 16384 3039 ip l2tp add session tunnel_id 1 name vmtunnel0 session_id \\ 3040 0xFFFFFFFF peer_session_id 0xFFFFFFFF 3041 ifconfig vmtunnel0 mtu 1500 3042 ifconfig vmtunnel0 up 3043 brctl addif br-lan vmtunnel0 3044 3045 3046 # on 4.3.2.1 3047 # launch QEMU instance - if your network has reorder or is very lossy add ,pincounter 3048 3049 |qemu_system| linux.img -device e1000,netdev=n1 \\ 3050 -netdev l2tpv3,id=n1,src=4.2.3.1,dst=1.2.3.4,udp,srcport=16384,dstport=16384,rxsession=0xffffffff,txsession=0xffffffff,counter 3051 3052``-netdev vde,id=id[,sock=socketpath][,port=n][,group=groupname][,mode=octalmode]`` 3053 Configure VDE backend to connect to PORT n of a vde switch running 3054 on host and listening for incoming connections on socketpath. Use 3055 GROUP groupname and MODE octalmode to change default ownership and 3056 permissions for communication port. This option is only available if 3057 QEMU has been compiled with vde support enabled. 3058 3059 Example: 3060 3061 .. parsed-literal:: 3062 3063 # launch vde switch 3064 vde_switch -F -sock /tmp/myswitch 3065 # launch QEMU instance 3066 |qemu_system| linux.img -nic vde,sock=/tmp/myswitch 3067 3068``-netdev vhost-user,chardev=id[,vhostforce=on|off][,queues=n]`` 3069 Establish a vhost-user netdev, backed by a chardev id. The chardev 3070 should be a unix domain socket backed one. The vhost-user uses a 3071 specifically defined protocol to pass vhost ioctl replacement 3072 messages to an application on the other end of the socket. On 3073 non-MSIX guests, the feature can be forced with vhostforce. Use 3074 'queues=n' to specify the number of queues to be created for 3075 multiqueue vhost-user. 3076 3077 Example: 3078 3079 :: 3080 3081 qemu -m 512 -object memory-backend-file,id=mem,size=512M,mem-path=/hugetlbfs,share=on \ 3082 -numa node,memdev=mem \ 3083 -chardev socket,id=chr0,path=/path/to/socket \ 3084 -netdev type=vhost-user,id=net0,chardev=chr0 \ 3085 -device virtio-net-pci,netdev=net0 3086 3087``-netdev vhost-vdpa,vhostdev=/path/to/dev`` 3088 Establish a vhost-vdpa netdev. 3089 3090 vDPA device is a device that uses a datapath which complies with 3091 the virtio specifications with a vendor specific control path. 3092 vDPA devices can be both physically located on the hardware or 3093 emulated by software. 3094 3095``-netdev hubport,id=id,hubid=hubid[,netdev=nd]`` 3096 Create a hub port on the emulated hub with ID hubid. 3097 3098 The hubport netdev lets you connect a NIC to a QEMU emulated hub 3099 instead of a single netdev. Alternatively, you can also connect the 3100 hubport to another netdev with ID nd by using the ``netdev=nd`` 3101 option. 3102 3103``-net nic[,netdev=nd][,macaddr=mac][,model=type] [,name=name][,addr=addr][,vectors=v]`` 3104 Legacy option to configure or create an on-board (or machine 3105 default) Network Interface Card(NIC) and connect it either to the 3106 emulated hub with ID 0 (i.e. the default hub), or to the netdev nd. 3107 If model is omitted, then the default NIC model associated with the 3108 machine type is used. Note that the default NIC model may change in 3109 future QEMU releases, so it is highly recommended to always specify 3110 a model. Optionally, the MAC address can be changed to mac, the 3111 device address set to addr (PCI cards only), and a name can be 3112 assigned for use in monitor commands. Optionally, for PCI cards, you 3113 can specify the number v of MSI-X vectors that the card should have; 3114 this option currently only affects virtio cards; set v = 0 to 3115 disable MSI-X. If no ``-net`` option is specified, a single NIC is 3116 created. QEMU can emulate several different models of network card. 3117 Use ``-net nic,model=help`` for a list of available devices for your 3118 target. 3119 3120``-net user|tap|bridge|socket|l2tpv3|vde[,...][,name=name]`` 3121 Configure a host network backend (with the options corresponding to 3122 the same ``-netdev`` option) and connect it to the emulated hub 0 3123 (the default hub). Use name to specify the name of the hub port. 3124ERST 3125 3126DEFHEADING() 3127 3128DEFHEADING(Character device options:) 3129 3130DEF("chardev", HAS_ARG, QEMU_OPTION_chardev, 3131 "-chardev help\n" 3132 "-chardev null,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3133 "-chardev socket,id=id[,host=host],port=port[,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off][,reconnect=seconds]\n" 3134 " [,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds][,mux=on|off]\n" 3135 " [,logfile=PATH][,logappend=on|off][,tls-creds=ID][,tls-authz=ID] (tcp)\n" 3136 "-chardev socket,id=id,path=path[,server=on|off][,wait=on|off][,telnet=on|off][,websocket=on|off][,reconnect=seconds]\n" 3137 " [,mux=on|off][,logfile=PATH][,logappend=on|off][,abstract=on|off][,tight=on|off] (unix)\n" 3138 "-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr]\n" 3139 " [,localport=localport][,ipv4=on|off][,ipv6=on|off][,mux=on|off]\n" 3140 " [,logfile=PATH][,logappend=on|off]\n" 3141 "-chardev msmouse,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3142 "-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]\n" 3143 " [,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3144 "-chardev ringbuf,id=id[,size=size][,logfile=PATH][,logappend=on|off]\n" 3145 "-chardev file,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3146 "-chardev pipe,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3147#ifdef _WIN32 3148 "-chardev console,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3149 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3150#else 3151 "-chardev pty,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3152 "-chardev stdio,id=id[,mux=on|off][,signal=on|off][,logfile=PATH][,logappend=on|off]\n" 3153#endif 3154#ifdef CONFIG_BRLAPI 3155 "-chardev braille,id=id[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3156#endif 3157#if defined(__linux__) || defined(__sun__) || defined(__FreeBSD__) \ 3158 || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__) 3159 "-chardev serial,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3160 "-chardev tty,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3161#endif 3162#if defined(__linux__) || defined(__FreeBSD__) || defined(__DragonFly__) 3163 "-chardev parallel,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3164 "-chardev parport,id=id,path=path[,mux=on|off][,logfile=PATH][,logappend=on|off]\n" 3165#endif 3166#if defined(CONFIG_SPICE) 3167 "-chardev spicevmc,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3168 "-chardev spiceport,id=id,name=name[,debug=debug][,logfile=PATH][,logappend=on|off]\n" 3169#endif 3170 , QEMU_ARCH_ALL 3171) 3172 3173SRST 3174The general form of a character device option is: 3175 3176``-chardev backend,id=id[,mux=on|off][,options]`` 3177 Backend is one of: ``null``, ``socket``, ``udp``, ``msmouse``, 3178 ``vc``, ``ringbuf``, ``file``, ``pipe``, ``console``, ``serial``, 3179 ``pty``, ``stdio``, ``braille``, ``tty``, ``parallel``, ``parport``, 3180 ``spicevmc``, ``spiceport``. The specific backend will determine the 3181 applicable options. 3182 3183 Use ``-chardev help`` to print all available chardev backend types. 3184 3185 All devices must have an id, which can be any string up to 127 3186 characters long. It is used to uniquely identify this device in 3187 other command line directives. 3188 3189 A character device may be used in multiplexing mode by multiple 3190 front-ends. Specify ``mux=on`` to enable this mode. A multiplexer is 3191 a "1:N" device, and here the "1" end is your specified chardev 3192 backend, and the "N" end is the various parts of QEMU that can talk 3193 to a chardev. If you create a chardev with ``id=myid`` and 3194 ``mux=on``, QEMU will create a multiplexer with your specified ID, 3195 and you can then configure multiple front ends to use that chardev 3196 ID for their input/output. Up to four different front ends can be 3197 connected to a single multiplexed chardev. (Without multiplexing 3198 enabled, a chardev can only be used by a single front end.) For 3199 instance you could use this to allow a single stdio chardev to be 3200 used by two serial ports and the QEMU monitor: 3201 3202 :: 3203 3204 -chardev stdio,mux=on,id=char0 \ 3205 -mon chardev=char0,mode=readline \ 3206 -serial chardev:char0 \ 3207 -serial chardev:char0 3208 3209 You can have more than one multiplexer in a system configuration; 3210 for instance you could have a TCP port multiplexed between UART 0 3211 and UART 1, and stdio multiplexed between the QEMU monitor and a 3212 parallel port: 3213 3214 :: 3215 3216 -chardev stdio,mux=on,id=char0 \ 3217 -mon chardev=char0,mode=readline \ 3218 -parallel chardev:char0 \ 3219 -chardev tcp,...,mux=on,id=char1 \ 3220 -serial chardev:char1 \ 3221 -serial chardev:char1 3222 3223 When you're using a multiplexed character device, some escape 3224 sequences are interpreted in the input. See the chapter about 3225 :ref:`keys in the character backend multiplexer` in the 3226 System Emulation Users Guide for more details. 3227 3228 Note that some other command line options may implicitly create 3229 multiplexed character backends; for instance ``-serial mon:stdio`` 3230 creates a multiplexed stdio backend connected to the serial port and 3231 the QEMU monitor, and ``-nographic`` also multiplexes the console 3232 and the monitor to stdio. 3233 3234 There is currently no support for multiplexing in the other 3235 direction (where a single QEMU front end takes input and output from 3236 multiple chardevs). 3237 3238 Every backend supports the ``logfile`` option, which supplies the 3239 path to a file to record all data transmitted via the backend. The 3240 ``logappend`` option controls whether the log file will be truncated 3241 or appended to when opened. 3242 3243The available backends are: 3244 3245``-chardev null,id=id`` 3246 A void device. This device will not emit any data, and will drop any 3247 data it receives. The null backend does not take any options. 3248 3249``-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]`` 3250 Create a two-way stream socket, which can be either a TCP or a unix 3251 socket. A unix socket will be created if ``path`` is specified. 3252 Behaviour is undefined if TCP options are specified for a unix 3253 socket. 3254 3255 ``server=on|off`` specifies that the socket shall be a listening socket. 3256 3257 ``wait=on|off`` specifies that QEMU should not block waiting for a client 3258 to connect to a listening socket. 3259 3260 ``telnet=on|off`` specifies that traffic on the socket should interpret 3261 telnet escape sequences. 3262 3263 ``websocket=on|off`` specifies that the socket uses WebSocket protocol for 3264 communication. 3265 3266 ``reconnect`` sets the timeout for reconnecting on non-server 3267 sockets when the remote end goes away. qemu will delay this many 3268 seconds and then attempt to reconnect. Zero disables reconnecting, 3269 and is the default. 3270 3271 ``tls-creds`` requests enablement of the TLS protocol for 3272 encryption, and specifies the id of the TLS credentials to use for 3273 the handshake. The credentials must be previously created with the 3274 ``-object tls-creds`` argument. 3275 3276 ``tls-auth`` provides the ID of the QAuthZ authorization object 3277 against which the client's x509 distinguished name will be 3278 validated. This object is only resolved at time of use, so can be 3279 deleted and recreated on the fly while the chardev server is active. 3280 If missing, it will default to denying access. 3281 3282 TCP and unix socket options are given below: 3283 3284 ``TCP options: port=port[,host=host][,to=to][,ipv4=on|off][,ipv6=on|off][,nodelay=on|off]`` 3285 ``host`` for a listening socket specifies the local address to 3286 be bound. For a connecting socket species the remote host to 3287 connect to. ``host`` is optional for listening sockets. If not 3288 specified it defaults to ``0.0.0.0``. 3289 3290 ``port`` for a listening socket specifies the local port to be 3291 bound. For a connecting socket specifies the port on the remote 3292 host to connect to. ``port`` can be given as either a port 3293 number or a service name. ``port`` is required. 3294 3295 ``to`` is only relevant to listening sockets. If it is 3296 specified, and ``port`` cannot be bound, QEMU will attempt to 3297 bind to subsequent ports up to and including ``to`` until it 3298 succeeds. ``to`` must be specified as a port number. 3299 3300 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 3301 or IPv6 must be used. If neither is specified the socket may 3302 use either protocol. 3303 3304 ``nodelay=on|off`` disables the Nagle algorithm. 3305 3306 ``unix options: path=path[,abstract=on|off][,tight=on|off]`` 3307 ``path`` specifies the local path of the unix socket. ``path`` 3308 is required. 3309 ``abstract=on|off`` specifies the use of the abstract socket namespace, 3310 rather than the filesystem. Optional, defaults to false. 3311 ``tight=on|off`` sets the socket length of abstract sockets to their minimum, 3312 rather than the full sun_path length. Optional, defaults to true. 3313 3314``-chardev udp,id=id[,host=host],port=port[,localaddr=localaddr][,localport=localport][,ipv4=on|off][,ipv6=on|off]`` 3315 Sends all traffic from the guest to a remote host over UDP. 3316 3317 ``host`` specifies the remote host to connect to. If not specified 3318 it defaults to ``localhost``. 3319 3320 ``port`` specifies the port on the remote host to connect to. 3321 ``port`` is required. 3322 3323 ``localaddr`` specifies the local address to bind to. If not 3324 specified it defaults to ``0.0.0.0``. 3325 3326 ``localport`` specifies the local port to bind to. If not specified 3327 any available local port will be used. 3328 3329 ``ipv4=on|off`` and ``ipv6=on|off`` specify that either IPv4 or IPv6 must be used. 3330 If neither is specified the device may use either protocol. 3331 3332``-chardev msmouse,id=id`` 3333 Forward QEMU's emulated msmouse events to the guest. ``msmouse`` 3334 does not take any options. 3335 3336``-chardev vc,id=id[[,width=width][,height=height]][[,cols=cols][,rows=rows]]`` 3337 Connect to a QEMU text console. ``vc`` may optionally be given a 3338 specific size. 3339 3340 ``width`` and ``height`` specify the width and height respectively 3341 of the console, in pixels. 3342 3343 ``cols`` and ``rows`` specify that the console be sized to fit a 3344 text console with the given dimensions. 3345 3346``-chardev ringbuf,id=id[,size=size]`` 3347 Create a ring buffer with fixed size ``size``. size must be a power 3348 of two and defaults to ``64K``. 3349 3350``-chardev file,id=id,path=path`` 3351 Log all traffic received from the guest to a file. 3352 3353 ``path`` specifies the path of the file to be opened. This file will 3354 be created if it does not already exist, and overwritten if it does. 3355 ``path`` is required. 3356 3357``-chardev pipe,id=id,path=path`` 3358 Create a two-way connection to the guest. The behaviour differs 3359 slightly between Windows hosts and other hosts: 3360 3361 On Windows, a single duplex pipe will be created at 3362 ``\\.pipe\path``. 3363 3364 On other hosts, 2 pipes will be created called ``path.in`` and 3365 ``path.out``. Data written to ``path.in`` will be received by the 3366 guest. Data written by the guest can be read from ``path.out``. QEMU 3367 will not create these fifos, and requires them to be present. 3368 3369 ``path`` forms part of the pipe path as described above. ``path`` is 3370 required. 3371 3372``-chardev console,id=id`` 3373 Send traffic from the guest to QEMU's standard output. ``console`` 3374 does not take any options. 3375 3376 ``console`` is only available on Windows hosts. 3377 3378``-chardev serial,id=id,path=path`` 3379 Send traffic from the guest to a serial device on the host. 3380 3381 On Unix hosts serial will actually accept any tty device, not only 3382 serial lines. 3383 3384 ``path`` specifies the name of the serial device to open. 3385 3386``-chardev pty,id=id`` 3387 Create a new pseudo-terminal on the host and connect to it. ``pty`` 3388 does not take any options. 3389 3390 ``pty`` is not available on Windows hosts. 3391 3392``-chardev stdio,id=id[,signal=on|off]`` 3393 Connect to standard input and standard output of the QEMU process. 3394 3395 ``signal`` controls if signals are enabled on the terminal, that 3396 includes exiting QEMU with the key sequence Control-c. This option 3397 is enabled by default, use ``signal=off`` to disable it. 3398 3399``-chardev braille,id=id`` 3400 Connect to a local BrlAPI server. ``braille`` does not take any 3401 options. 3402 3403``-chardev tty,id=id,path=path`` 3404 ``tty`` is only available on Linux, Sun, FreeBSD, NetBSD, OpenBSD 3405 and DragonFlyBSD hosts. It is an alias for ``serial``. 3406 3407 ``path`` specifies the path to the tty. ``path`` is required. 3408 3409``-chardev parallel,id=id,path=path`` 3410 \ 3411``-chardev parport,id=id,path=path`` 3412 ``parallel`` is only available on Linux, FreeBSD and DragonFlyBSD 3413 hosts. 3414 3415 Connect to a local parallel port. 3416 3417 ``path`` specifies the path to the parallel port device. ``path`` is 3418 required. 3419 3420``-chardev spicevmc,id=id,debug=debug,name=name`` 3421 ``spicevmc`` is only available when spice support is built in. 3422 3423 ``debug`` debug level for spicevmc 3424 3425 ``name`` name of spice channel to connect to 3426 3427 Connect to a spice virtual machine channel, such as vdiport. 3428 3429``-chardev spiceport,id=id,debug=debug,name=name`` 3430 ``spiceport`` is only available when spice support is built in. 3431 3432 ``debug`` debug level for spicevmc 3433 3434 ``name`` name of spice port to connect to 3435 3436 Connect to a spice port, allowing a Spice client to handle the 3437 traffic identified by a name (preferably a fqdn). 3438ERST 3439 3440DEFHEADING() 3441 3442#ifdef CONFIG_TPM 3443DEFHEADING(TPM device options:) 3444 3445DEF("tpmdev", HAS_ARG, QEMU_OPTION_tpmdev, \ 3446 "-tpmdev passthrough,id=id[,path=path][,cancel-path=path]\n" 3447 " use path to provide path to a character device; default is /dev/tpm0\n" 3448 " use cancel-path to provide path to TPM's cancel sysfs entry; if\n" 3449 " not provided it will be searched for in /sys/class/misc/tpm?/device\n" 3450 "-tpmdev emulator,id=id,chardev=dev\n" 3451 " configure the TPM device using chardev backend\n", 3452 QEMU_ARCH_ALL) 3453SRST 3454The general form of a TPM device option is: 3455 3456``-tpmdev backend,id=id[,options]`` 3457 The specific backend type will determine the applicable options. The 3458 ``-tpmdev`` option creates the TPM backend and requires a 3459 ``-device`` option that specifies the TPM frontend interface model. 3460 3461 Use ``-tpmdev help`` to print all available TPM backend types. 3462 3463The available backends are: 3464 3465``-tpmdev passthrough,id=id,path=path,cancel-path=cancel-path`` 3466 (Linux-host only) Enable access to the host's TPM using the 3467 passthrough driver. 3468 3469 ``path`` specifies the path to the host's TPM device, i.e., on a 3470 Linux host this would be ``/dev/tpm0``. ``path`` is optional and by 3471 default ``/dev/tpm0`` is used. 3472 3473 ``cancel-path`` specifies the path to the host TPM device's sysfs 3474 entry allowing for cancellation of an ongoing TPM command. 3475 ``cancel-path`` is optional and by default QEMU will search for the 3476 sysfs entry to use. 3477 3478 Some notes about using the host's TPM with the passthrough driver: 3479 3480 The TPM device accessed by the passthrough driver must not be used 3481 by any other application on the host. 3482 3483 Since the host's firmware (BIOS/UEFI) has already initialized the 3484 TPM, the VM's firmware (BIOS/UEFI) will not be able to initialize 3485 the TPM again and may therefore not show a TPM-specific menu that 3486 would otherwise allow the user to configure the TPM, e.g., allow the 3487 user to enable/disable or activate/deactivate the TPM. Further, if 3488 TPM ownership is released from within a VM then the host's TPM will 3489 get disabled and deactivated. To enable and activate the TPM again 3490 afterwards, the host has to be rebooted and the user is required to 3491 enter the firmware's menu to enable and activate the TPM. If the TPM 3492 is left disabled and/or deactivated most TPM commands will fail. 3493 3494 To create a passthrough TPM use the following two options: 3495 3496 :: 3497 3498 -tpmdev passthrough,id=tpm0 -device tpm-tis,tpmdev=tpm0 3499 3500 Note that the ``-tpmdev`` id is ``tpm0`` and is referenced by 3501 ``tpmdev=tpm0`` in the device option. 3502 3503``-tpmdev emulator,id=id,chardev=dev`` 3504 (Linux-host only) Enable access to a TPM emulator using Unix domain 3505 socket based chardev backend. 3506 3507 ``chardev`` specifies the unique ID of a character device backend 3508 that provides connection to the software TPM server. 3509 3510 To create a TPM emulator backend device with chardev socket backend: 3511 3512 :: 3513 3514 -chardev socket,id=chrtpm,path=/tmp/swtpm-sock -tpmdev emulator,id=tpm0,chardev=chrtpm -device tpm-tis,tpmdev=tpm0 3515ERST 3516 3517DEFHEADING() 3518 3519#endif 3520 3521DEFHEADING(Linux/Multiboot boot specific:) 3522SRST 3523When using these options, you can use a given Linux or Multiboot kernel 3524without installing it in the disk image. It can be useful for easier 3525testing of various kernels. 3526 3527 3528ERST 3529 3530DEF("kernel", HAS_ARG, QEMU_OPTION_kernel, \ 3531 "-kernel bzImage use 'bzImage' as kernel image\n", QEMU_ARCH_ALL) 3532SRST 3533``-kernel bzImage`` 3534 Use bzImage as kernel image. The kernel can be either a Linux kernel 3535 or in multiboot format. 3536ERST 3537 3538DEF("append", HAS_ARG, QEMU_OPTION_append, \ 3539 "-append cmdline use 'cmdline' as kernel command line\n", QEMU_ARCH_ALL) 3540SRST 3541``-append cmdline`` 3542 Use cmdline as kernel command line 3543ERST 3544 3545DEF("initrd", HAS_ARG, QEMU_OPTION_initrd, \ 3546 "-initrd file use 'file' as initial ram disk\n", QEMU_ARCH_ALL) 3547SRST 3548``-initrd file`` 3549 Use file as initial ram disk. 3550 3551``-initrd "file1 arg=foo,file2"`` 3552 This syntax is only available with multiboot. 3553 3554 Use file1 and file2 as modules and pass arg=foo as parameter to the 3555 first module. 3556ERST 3557 3558DEF("dtb", HAS_ARG, QEMU_OPTION_dtb, \ 3559 "-dtb file use 'file' as device tree image\n", QEMU_ARCH_ALL) 3560SRST 3561``-dtb file`` 3562 Use file as a device tree binary (dtb) image and pass it to the 3563 kernel on boot. 3564ERST 3565 3566DEFHEADING() 3567 3568DEFHEADING(Debug/Expert options:) 3569 3570DEF("compat", HAS_ARG, QEMU_OPTION_compat, 3571 "-compat [deprecated-input=accept|reject|crash][,deprecated-output=accept|hide]\n" 3572 " Policy for handling deprecated management interfaces\n", 3573 QEMU_ARCH_ALL) 3574SRST 3575``-compat [deprecated-input=@var{input-policy}][,deprecated-output=@var{output-policy}]`` 3576 Set policy for handling deprecated management interfaces (experimental): 3577 3578 ``deprecated-input=accept`` (default) 3579 Accept deprecated commands and arguments 3580 ``deprecated-input=reject`` 3581 Reject deprecated commands and arguments 3582 ``deprecated-input=crash`` 3583 Crash on deprecated commands and arguments 3584 ``deprecated-output=accept`` (default) 3585 Emit deprecated command results and events 3586 ``deprecated-output=hide`` 3587 Suppress deprecated command results and events 3588 3589 Limitation: covers only syntactic aspects of QMP. 3590ERST 3591 3592DEF("fw_cfg", HAS_ARG, QEMU_OPTION_fwcfg, 3593 "-fw_cfg [name=]<name>,file=<file>\n" 3594 " add named fw_cfg entry with contents from file\n" 3595 "-fw_cfg [name=]<name>,string=<str>\n" 3596 " add named fw_cfg entry with contents from string\n", 3597 QEMU_ARCH_ALL) 3598SRST 3599``-fw_cfg [name=]name,file=file`` 3600 Add named fw\_cfg entry with contents from file file. 3601 3602``-fw_cfg [name=]name,string=str`` 3603 Add named fw\_cfg entry with contents from string str. 3604 3605 The terminating NUL character of the contents of str will not be 3606 included as part of the fw\_cfg item data. To insert contents with 3607 embedded NUL characters, you have to use the file parameter. 3608 3609 The fw\_cfg entries are passed by QEMU through to the guest. 3610 3611 Example: 3612 3613 :: 3614 3615 -fw_cfg name=opt/com.mycompany/blob,file=./my_blob.bin 3616 3617 creates an fw\_cfg entry named opt/com.mycompany/blob with contents 3618 from ./my\_blob.bin. 3619ERST 3620 3621DEF("serial", HAS_ARG, QEMU_OPTION_serial, \ 3622 "-serial dev redirect the serial port to char device 'dev'\n", 3623 QEMU_ARCH_ALL) 3624SRST 3625``-serial dev`` 3626 Redirect the virtual serial port to host character device dev. The 3627 default device is ``vc`` in graphical mode and ``stdio`` in non 3628 graphical mode. 3629 3630 This option can be used several times to simulate up to 4 serial 3631 ports. 3632 3633 Use ``-serial none`` to disable all serial ports. 3634 3635 Available character devices are: 3636 3637 ``vc[:WxH]`` 3638 Virtual console. Optionally, a width and height can be given in 3639 pixel with 3640 3641 :: 3642 3643 vc:800x600 3644 3645 It is also possible to specify width or height in characters: 3646 3647 :: 3648 3649 vc:80Cx24C 3650 3651 ``pty`` 3652 [Linux only] Pseudo TTY (a new PTY is automatically allocated) 3653 3654 ``none`` 3655 No device is allocated. 3656 3657 ``null`` 3658 void device 3659 3660 ``chardev:id`` 3661 Use a named character device defined with the ``-chardev`` 3662 option. 3663 3664 ``/dev/XXX`` 3665 [Linux only] Use host tty, e.g. ``/dev/ttyS0``. The host serial 3666 port parameters are set according to the emulated ones. 3667 3668 ``/dev/parportN`` 3669 [Linux only, parallel port only] Use host parallel port N. 3670 Currently SPP and EPP parallel port features can be used. 3671 3672 ``file:filename`` 3673 Write output to filename. No character can be read. 3674 3675 ``stdio`` 3676 [Unix only] standard input/output 3677 3678 ``pipe:filename`` 3679 name pipe filename 3680 3681 ``COMn`` 3682 [Windows only] Use host serial port n 3683 3684 ``udp:[remote_host]:remote_port[@[src_ip]:src_port]`` 3685 This implements UDP Net Console. When remote\_host or src\_ip 3686 are not specified they default to ``0.0.0.0``. When not using a 3687 specified src\_port a random port is automatically chosen. 3688 3689 If you just want a simple readonly console you can use 3690 ``netcat`` or ``nc``, by starting QEMU with: 3691 ``-serial udp::4555`` and nc as: ``nc -u -l -p 4555``. Any time 3692 QEMU writes something to that port it will appear in the 3693 netconsole session. 3694 3695 If you plan to send characters back via netconsole or you want 3696 to stop and start QEMU a lot of times, you should have QEMU use 3697 the same source port each time by using something like ``-serial 3698 udp::4555@:4556`` to QEMU. Another approach is to use a patched 3699 version of netcat which can listen to a TCP port and send and 3700 receive characters via udp. If you have a patched version of 3701 netcat which activates telnet remote echo and single char 3702 transfer, then you can use the following options to set up a 3703 netcat redirector to allow telnet on port 5555 to access the 3704 QEMU port. 3705 3706 ``QEMU Options:`` 3707 -serial udp::4555@:4556 3708 3709 ``netcat options:`` 3710 -u -P 4555 -L 0.0.0.0:4556 -t -p 5555 -I -T 3711 3712 ``telnet options:`` 3713 localhost 5555 3714 3715 ``tcp:[host]:port[,server=on|off][,wait=on|off][,nodelay=on|off][,reconnect=seconds]`` 3716 The TCP Net Console has two modes of operation. It can send the 3717 serial I/O to a location or wait for a connection from a 3718 location. By default the TCP Net Console is sent to host at the 3719 port. If you use the ``server=on`` option QEMU will wait for a client 3720 socket application to connect to the port before continuing, 3721 unless the ``wait=on|off`` option was specified. The ``nodelay=on|off`` 3722 option disables the Nagle buffering algorithm. The ``reconnect=on`` 3723 option only applies if ``server=no`` is set, if the connection goes 3724 down it will attempt to reconnect at the given interval. If host 3725 is omitted, 0.0.0.0 is assumed. Only one TCP connection at a 3726 time is accepted. You can use ``telnet=on`` to connect to the 3727 corresponding character device. 3728 3729 ``Example to send tcp console to 192.168.0.2 port 4444`` 3730 -serial tcp:192.168.0.2:4444 3731 3732 ``Example to listen and wait on port 4444 for connection`` 3733 -serial tcp::4444,server=on 3734 3735 ``Example to not wait and listen on ip 192.168.0.100 port 4444`` 3736 -serial tcp:192.168.0.100:4444,server=on,wait=off 3737 3738 ``telnet:host:port[,server=on|off][,wait=on|off][,nodelay=on|off]`` 3739 The telnet protocol is used instead of raw tcp sockets. The 3740 options work the same as if you had specified ``-serial tcp``. 3741 The difference is that the port acts like a telnet server or 3742 client using telnet option negotiation. This will also allow you 3743 to send the MAGIC\_SYSRQ sequence if you use a telnet that 3744 supports sending the break sequence. Typically in unix telnet 3745 you do it with Control-] and then type "send break" followed by 3746 pressing the enter key. 3747 3748 ``websocket:host:port,server=on[,wait=on|off][,nodelay=on|off]`` 3749 The WebSocket protocol is used instead of raw tcp socket. The 3750 port acts as a WebSocket server. Client mode is not supported. 3751 3752 ``unix:path[,server=on|off][,wait=on|off][,reconnect=seconds]`` 3753 A unix domain socket is used instead of a tcp socket. The option 3754 works the same as if you had specified ``-serial tcp`` except 3755 the unix domain socket path is used for connections. 3756 3757 ``mon:dev_string`` 3758 This is a special option to allow the monitor to be multiplexed 3759 onto another serial port. The monitor is accessed with key 3760 sequence of Control-a and then pressing c. dev\_string should be 3761 any one of the serial devices specified above. An example to 3762 multiplex the monitor onto a telnet server listening on port 3763 4444 would be: 3764 3765 ``-serial mon:telnet::4444,server=on,wait=off`` 3766 3767 When the monitor is multiplexed to stdio in this way, Ctrl+C 3768 will not terminate QEMU any more but will be passed to the guest 3769 instead. 3770 3771 ``braille`` 3772 Braille device. This will use BrlAPI to display the braille 3773 output on a real or fake device. 3774 3775 ``msmouse`` 3776 Three button serial mouse. Configure the guest to use Microsoft 3777 protocol. 3778ERST 3779 3780DEF("parallel", HAS_ARG, QEMU_OPTION_parallel, \ 3781 "-parallel dev redirect the parallel port to char device 'dev'\n", 3782 QEMU_ARCH_ALL) 3783SRST 3784``-parallel dev`` 3785 Redirect the virtual parallel port to host device dev (same devices 3786 as the serial port). On Linux hosts, ``/dev/parportN`` can be used 3787 to use hardware devices connected on the corresponding host parallel 3788 port. 3789 3790 This option can be used several times to simulate up to 3 parallel 3791 ports. 3792 3793 Use ``-parallel none`` to disable all parallel ports. 3794ERST 3795 3796DEF("monitor", HAS_ARG, QEMU_OPTION_monitor, \ 3797 "-monitor dev redirect the monitor to char device 'dev'\n", 3798 QEMU_ARCH_ALL) 3799SRST 3800``-monitor dev`` 3801 Redirect the monitor to host device dev (same devices as the serial 3802 port). The default device is ``vc`` in graphical mode and ``stdio`` 3803 in non graphical mode. Use ``-monitor none`` to disable the default 3804 monitor. 3805ERST 3806DEF("qmp", HAS_ARG, QEMU_OPTION_qmp, \ 3807 "-qmp dev like -monitor but opens in 'control' mode\n", 3808 QEMU_ARCH_ALL) 3809SRST 3810``-qmp dev`` 3811 Like -monitor but opens in 'control' mode. 3812ERST 3813DEF("qmp-pretty", HAS_ARG, QEMU_OPTION_qmp_pretty, \ 3814 "-qmp-pretty dev like -qmp but uses pretty JSON formatting\n", 3815 QEMU_ARCH_ALL) 3816SRST 3817``-qmp-pretty dev`` 3818 Like -qmp but uses pretty JSON formatting. 3819ERST 3820 3821DEF("mon", HAS_ARG, QEMU_OPTION_mon, \ 3822 "-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]\n", QEMU_ARCH_ALL) 3823SRST 3824``-mon [chardev=]name[,mode=readline|control][,pretty[=on|off]]`` 3825 Setup monitor on chardev name. ``mode=control`` configures 3826 a QMP monitor (a JSON RPC-style protocol) and it is not the 3827 same as HMP, the human monitor that has a "(qemu)" prompt. 3828 ``pretty`` is only valid when ``mode=control``, 3829 turning on JSON pretty printing to ease 3830 human reading and debugging. 3831ERST 3832 3833DEF("debugcon", HAS_ARG, QEMU_OPTION_debugcon, \ 3834 "-debugcon dev redirect the debug console to char device 'dev'\n", 3835 QEMU_ARCH_ALL) 3836SRST 3837``-debugcon dev`` 3838 Redirect the debug console to host device dev (same devices as the 3839 serial port). The debug console is an I/O port which is typically 3840 port 0xe9; writing to that I/O port sends output to this device. The 3841 default device is ``vc`` in graphical mode and ``stdio`` in non 3842 graphical mode. 3843ERST 3844 3845DEF("pidfile", HAS_ARG, QEMU_OPTION_pidfile, \ 3846 "-pidfile file write PID to 'file'\n", QEMU_ARCH_ALL) 3847SRST 3848``-pidfile file`` 3849 Store the QEMU process PID in file. It is useful if you launch QEMU 3850 from a script. 3851ERST 3852 3853DEF("singlestep", 0, QEMU_OPTION_singlestep, \ 3854 "-singlestep always run in singlestep mode\n", QEMU_ARCH_ALL) 3855SRST 3856``-singlestep`` 3857 Run the emulation in single step mode. 3858ERST 3859 3860DEF("preconfig", 0, QEMU_OPTION_preconfig, \ 3861 "--preconfig pause QEMU before machine is initialized (experimental)\n", 3862 QEMU_ARCH_ALL) 3863SRST 3864``--preconfig`` 3865 Pause QEMU for interactive configuration before the machine is 3866 created, which allows querying and configuring properties that will 3867 affect machine initialization. Use QMP command 'x-exit-preconfig' to 3868 exit the preconfig state and move to the next state (i.e. run guest 3869 if -S isn't used or pause the second time if -S is used). This 3870 option is experimental. 3871ERST 3872 3873DEF("S", 0, QEMU_OPTION_S, \ 3874 "-S freeze CPU at startup (use 'c' to start execution)\n", 3875 QEMU_ARCH_ALL) 3876SRST 3877``-S`` 3878 Do not start CPU at startup (you must type 'c' in the monitor). 3879ERST 3880 3881DEF("overcommit", HAS_ARG, QEMU_OPTION_overcommit, 3882 "-overcommit [mem-lock=on|off][cpu-pm=on|off]\n" 3883 " run qemu with overcommit hints\n" 3884 " mem-lock=on|off controls memory lock support (default: off)\n" 3885 " cpu-pm=on|off controls cpu power management (default: off)\n", 3886 QEMU_ARCH_ALL) 3887SRST 3888``-overcommit mem-lock=on|off`` 3889 \ 3890``-overcommit cpu-pm=on|off`` 3891 Run qemu with hints about host resource overcommit. The default is 3892 to assume that host overcommits all resources. 3893 3894 Locking qemu and guest memory can be enabled via ``mem-lock=on`` 3895 (disabled by default). This works when host memory is not 3896 overcommitted and reduces the worst-case latency for guest. 3897 3898 Guest ability to manage power state of host cpus (increasing latency 3899 for other processes on the same host cpu, but decreasing latency for 3900 guest) can be enabled via ``cpu-pm=on`` (disabled by default). This 3901 works best when host CPU is not overcommitted. When used, host 3902 estimates of CPU cycle and power utilization will be incorrect, not 3903 taking into account guest idle time. 3904ERST 3905 3906DEF("gdb", HAS_ARG, QEMU_OPTION_gdb, \ 3907 "-gdb dev accept gdb connection on 'dev'. (QEMU defaults to starting\n" 3908 " the guest without waiting for gdb to connect; use -S too\n" 3909 " if you want it to not start execution.)\n", 3910 QEMU_ARCH_ALL) 3911SRST 3912``-gdb dev`` 3913 Accept a gdb connection on device dev (see the :ref:`GDB usage` chapter 3914 in the System Emulation Users Guide). Note that this option does not pause QEMU 3915 execution -- if you want QEMU to not start the guest until you 3916 connect with gdb and issue a ``continue`` command, you will need to 3917 also pass the ``-S`` option to QEMU. 3918 3919 The most usual configuration is to listen on a local TCP socket:: 3920 3921 -gdb tcp::3117 3922 3923 but you can specify other backends; UDP, pseudo TTY, or even stdio 3924 are all reasonable use cases. For example, a stdio connection 3925 allows you to start QEMU from within gdb and establish the 3926 connection via a pipe: 3927 3928 .. parsed-literal:: 3929 3930 (gdb) target remote | exec |qemu_system| -gdb stdio ... 3931ERST 3932 3933DEF("s", 0, QEMU_OPTION_s, \ 3934 "-s shorthand for -gdb tcp::" DEFAULT_GDBSTUB_PORT "\n", 3935 QEMU_ARCH_ALL) 3936SRST 3937``-s`` 3938 Shorthand for -gdb tcp::1234, i.e. open a gdbserver on TCP port 1234 3939 (see the :ref:`GDB usage` chapter in the System Emulation Users Guide). 3940ERST 3941 3942DEF("d", HAS_ARG, QEMU_OPTION_d, \ 3943 "-d item1,... enable logging of specified items (use '-d help' for a list of log items)\n", 3944 QEMU_ARCH_ALL) 3945SRST 3946``-d item1[,...]`` 3947 Enable logging of specified items. Use '-d help' for a list of log 3948 items. 3949ERST 3950 3951DEF("D", HAS_ARG, QEMU_OPTION_D, \ 3952 "-D logfile output log to logfile (default stderr)\n", 3953 QEMU_ARCH_ALL) 3954SRST 3955``-D logfile`` 3956 Output log in logfile instead of to stderr 3957ERST 3958 3959DEF("dfilter", HAS_ARG, QEMU_OPTION_DFILTER, \ 3960 "-dfilter range,.. filter debug output to range of addresses (useful for -d cpu,exec,etc..)\n", 3961 QEMU_ARCH_ALL) 3962SRST 3963``-dfilter range1[,...]`` 3964 Filter debug output to that relevant to a range of target addresses. 3965 The filter spec can be either start+size, start-size or start..end 3966 where start end and size are the addresses and sizes required. For 3967 example: 3968 3969 :: 3970 3971 -dfilter 0x8000..0x8fff,0xffffffc000080000+0x200,0xffffffc000060000-0x1000 3972 3973 Will dump output for any code in the 0x1000 sized block starting at 3974 0x8000 and the 0x200 sized block starting at 0xffffffc000080000 and 3975 another 0x1000 sized block starting at 0xffffffc00005f000. 3976ERST 3977 3978DEF("seed", HAS_ARG, QEMU_OPTION_seed, \ 3979 "-seed number seed the pseudo-random number generator\n", 3980 QEMU_ARCH_ALL) 3981SRST 3982``-seed number`` 3983 Force the guest to use a deterministic pseudo-random number 3984 generator, seeded with number. This does not affect crypto routines 3985 within the host. 3986ERST 3987 3988DEF("L", HAS_ARG, QEMU_OPTION_L, \ 3989 "-L path set the directory for the BIOS, VGA BIOS and keymaps\n", 3990 QEMU_ARCH_ALL) 3991SRST 3992``-L path`` 3993 Set the directory for the BIOS, VGA BIOS and keymaps. 3994 3995 To list all the data directories, use ``-L help``. 3996ERST 3997 3998DEF("bios", HAS_ARG, QEMU_OPTION_bios, \ 3999 "-bios file set the filename for the BIOS\n", QEMU_ARCH_ALL) 4000SRST 4001``-bios file`` 4002 Set the filename for the BIOS. 4003ERST 4004 4005DEF("enable-kvm", 0, QEMU_OPTION_enable_kvm, \ 4006 "-enable-kvm enable KVM full virtualization support\n", QEMU_ARCH_ALL) 4007SRST 4008``-enable-kvm`` 4009 Enable KVM full virtualization support. This option is only 4010 available if KVM support is enabled when compiling. 4011ERST 4012 4013DEF("xen-domid", HAS_ARG, QEMU_OPTION_xen_domid, 4014 "-xen-domid id specify xen guest domain id\n", QEMU_ARCH_ALL) 4015DEF("xen-attach", 0, QEMU_OPTION_xen_attach, 4016 "-xen-attach attach to existing xen domain\n" 4017 " libxl will use this when starting QEMU\n", 4018 QEMU_ARCH_ALL) 4019DEF("xen-domid-restrict", 0, QEMU_OPTION_xen_domid_restrict, 4020 "-xen-domid-restrict restrict set of available xen operations\n" 4021 " to specified domain id. (Does not affect\n" 4022 " xenpv machine type).\n", 4023 QEMU_ARCH_ALL) 4024SRST 4025``-xen-domid id`` 4026 Specify xen guest domain id (XEN only). 4027 4028``-xen-attach`` 4029 Attach to existing xen domain. libxl will use this when starting 4030 QEMU (XEN only). Restrict set of available xen operations to 4031 specified domain id (XEN only). 4032ERST 4033 4034DEF("no-reboot", 0, QEMU_OPTION_no_reboot, \ 4035 "-no-reboot exit instead of rebooting\n", QEMU_ARCH_ALL) 4036SRST 4037``-no-reboot`` 4038 Exit instead of rebooting. 4039ERST 4040 4041DEF("no-shutdown", 0, QEMU_OPTION_no_shutdown, \ 4042 "-no-shutdown stop before shutdown\n", QEMU_ARCH_ALL) 4043SRST 4044``-no-shutdown`` 4045 Don't exit QEMU on guest shutdown, but instead only stop the 4046 emulation. This allows for instance switching to monitor to commit 4047 changes to the disk image. 4048ERST 4049 4050DEF("action", HAS_ARG, QEMU_OPTION_action, 4051 "-action reboot=reset|shutdown\n" 4052 " action when guest reboots [default=reset]\n" 4053 "-action shutdown=poweroff|pause\n" 4054 " action when guest shuts down [default=poweroff]\n" 4055 "-action panic=pause|shutdown|none\n" 4056 " action when guest panics [default=shutdown]\n" 4057 "-action watchdog=reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" 4058 " action when watchdog fires [default=reset]\n", 4059 QEMU_ARCH_ALL) 4060SRST 4061``-action event=action`` 4062 The action parameter serves to modify QEMU's default behavior when 4063 certain guest events occur. It provides a generic method for specifying the 4064 same behaviors that are modified by the ``-no-reboot`` and ``-no-shutdown`` 4065 parameters. 4066 4067 Examples: 4068 4069 ``-action panic=none`` 4070 ``-action reboot=shutdown,shutdown=pause`` 4071 ``-watchdog i6300esb -action watchdog=pause`` 4072 4073ERST 4074 4075DEF("loadvm", HAS_ARG, QEMU_OPTION_loadvm, \ 4076 "-loadvm [tag|id]\n" \ 4077 " start right away with a saved state (loadvm in monitor)\n", 4078 QEMU_ARCH_ALL) 4079SRST 4080``-loadvm file`` 4081 Start right away with a saved state (``loadvm`` in monitor) 4082ERST 4083 4084#ifndef _WIN32 4085DEF("daemonize", 0, QEMU_OPTION_daemonize, \ 4086 "-daemonize daemonize QEMU after initializing\n", QEMU_ARCH_ALL) 4087#endif 4088SRST 4089``-daemonize`` 4090 Daemonize the QEMU process after initialization. QEMU will not 4091 detach from standard IO until it is ready to receive connections on 4092 any of its devices. This option is a useful way for external 4093 programs to launch QEMU without having to cope with initialization 4094 race conditions. 4095ERST 4096 4097DEF("option-rom", HAS_ARG, QEMU_OPTION_option_rom, \ 4098 "-option-rom rom load a file, rom, into the option ROM space\n", 4099 QEMU_ARCH_ALL) 4100SRST 4101``-option-rom file`` 4102 Load the contents of file as an option ROM. This option is useful to 4103 load things like EtherBoot. 4104ERST 4105 4106DEF("rtc", HAS_ARG, QEMU_OPTION_rtc, \ 4107 "-rtc [base=utc|localtime|<datetime>][,clock=host|rt|vm][,driftfix=none|slew]\n" \ 4108 " set the RTC base and clock, enable drift fix for clock ticks (x86 only)\n", 4109 QEMU_ARCH_ALL) 4110 4111SRST 4112``-rtc [base=utc|localtime|datetime][,clock=host|rt|vm][,driftfix=none|slew]`` 4113 Specify ``base`` as ``utc`` or ``localtime`` to let the RTC start at 4114 the current UTC or local time, respectively. ``localtime`` is 4115 required for correct date in MS-DOS or Windows. To start at a 4116 specific point in time, provide datetime in the format 4117 ``2006-06-17T16:01:21`` or ``2006-06-17``. The default base is UTC. 4118 4119 By default the RTC is driven by the host system time. This allows 4120 using of the RTC as accurate reference clock inside the guest, 4121 specifically if the host time is smoothly following an accurate 4122 external reference clock, e.g. via NTP. If you want to isolate the 4123 guest time from the host, you can set ``clock`` to ``rt`` instead, 4124 which provides a host monotonic clock if host support it. To even 4125 prevent the RTC from progressing during suspension, you can set 4126 ``clock`` to ``vm`` (virtual clock). '\ ``clock=vm``\ ' is 4127 recommended especially in icount mode in order to preserve 4128 determinism; however, note that in icount mode the speed of the 4129 virtual clock is variable and can in general differ from the host 4130 clock. 4131 4132 Enable ``driftfix`` (i386 targets only) if you experience time drift 4133 problems, specifically with Windows' ACPI HAL. This option will try 4134 to figure out how many timer interrupts were not processed by the 4135 Windows guest and will re-inject them. 4136ERST 4137 4138DEF("icount", HAS_ARG, QEMU_OPTION_icount, \ 4139 "-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=<filename>[,rrsnapshot=<snapshot>]]\n" \ 4140 " enable virtual instruction counter with 2^N clock ticks per\n" \ 4141 " instruction, enable aligning the host and virtual clocks\n" \ 4142 " or disable real time cpu sleeping, and optionally enable\n" \ 4143 " record-and-replay mode\n", QEMU_ARCH_ALL) 4144SRST 4145``-icount [shift=N|auto][,align=on|off][,sleep=on|off][,rr=record|replay,rrfile=filename[,rrsnapshot=snapshot]]`` 4146 Enable virtual instruction counter. The virtual cpu will execute one 4147 instruction every 2^N ns of virtual time. If ``auto`` is specified 4148 then the virtual cpu speed will be automatically adjusted to keep 4149 virtual time within a few seconds of real time. 4150 4151 Note that while this option can give deterministic behavior, it does 4152 not provide cycle accurate emulation. Modern CPUs contain 4153 superscalar out of order cores with complex cache hierarchies. The 4154 number of instructions executed often has little or no correlation 4155 with actual performance. 4156 4157 When the virtual cpu is sleeping, the virtual time will advance at 4158 default speed unless ``sleep=on`` is specified. With 4159 ``sleep=on``, the virtual time will jump to the next timer 4160 deadline instantly whenever the virtual cpu goes to sleep mode and 4161 will not advance if no timer is enabled. This behavior gives 4162 deterministic execution times from the guest point of view. 4163 The default if icount is enabled is ``sleep=off``. 4164 ``sleep=on`` cannot be used together with either ``shift=auto`` 4165 or ``align=on``. 4166 4167 ``align=on`` will activate the delay algorithm which will try to 4168 synchronise the host clock and the virtual clock. The goal is to 4169 have a guest running at the real frequency imposed by the shift 4170 option. Whenever the guest clock is behind the host clock and if 4171 ``align=on`` is specified then we print a message to the user to 4172 inform about the delay. Currently this option does not work when 4173 ``shift`` is ``auto``. Note: The sync algorithm will work for those 4174 shift values for which the guest clock runs ahead of the host clock. 4175 Typically this happens when the shift value is high (how high 4176 depends on the host machine). The default if icount is enabled 4177 is ``align=off``. 4178 4179 When the ``rr`` option is specified deterministic record/replay is 4180 enabled. The ``rrfile=`` option must also be provided to 4181 specify the path to the replay log. In record mode data is written 4182 to this file, and in replay mode it is read back. 4183 If the ``rrsnapshot`` option is given then it specifies a VM snapshot 4184 name. In record mode, a new VM snapshot with the given name is created 4185 at the start of execution recording. In replay mode this option 4186 specifies the snapshot name used to load the initial VM state. 4187ERST 4188 4189DEF("watchdog", HAS_ARG, QEMU_OPTION_watchdog, \ 4190 "-watchdog model\n" \ 4191 " enable virtual hardware watchdog [default=none]\n", 4192 QEMU_ARCH_ALL) 4193SRST 4194``-watchdog model`` 4195 Create a virtual hardware watchdog device. Once enabled (by a guest 4196 action), the watchdog must be periodically polled by an agent inside 4197 the guest or else the guest will be restarted. Choose a model for 4198 which your guest has drivers. 4199 4200 The model is the model of hardware watchdog to emulate. Use 4201 ``-watchdog help`` to list available hardware models. Only one 4202 watchdog can be enabled for a guest. 4203 4204 The following models may be available: 4205 4206 ``ib700`` 4207 iBASE 700 is a very simple ISA watchdog with a single timer. 4208 4209 ``i6300esb`` 4210 Intel 6300ESB I/O controller hub is a much more featureful 4211 PCI-based dual-timer watchdog. 4212 4213 ``diag288`` 4214 A virtual watchdog for s390x backed by the diagnose 288 4215 hypercall (currently KVM only). 4216ERST 4217 4218DEF("watchdog-action", HAS_ARG, QEMU_OPTION_watchdog_action, \ 4219 "-watchdog-action reset|shutdown|poweroff|inject-nmi|pause|debug|none\n" \ 4220 " action when watchdog fires [default=reset]\n", 4221 QEMU_ARCH_ALL) 4222SRST 4223``-watchdog-action action`` 4224 The action controls what QEMU will do when the watchdog timer 4225 expires. The default is ``reset`` (forcefully reset the guest). 4226 Other possible actions are: ``shutdown`` (attempt to gracefully 4227 shutdown the guest), ``poweroff`` (forcefully poweroff the guest), 4228 ``inject-nmi`` (inject a NMI into the guest), ``pause`` (pause the 4229 guest), ``debug`` (print a debug message and continue), or ``none`` 4230 (do nothing). 4231 4232 Note that the ``shutdown`` action requires that the guest responds 4233 to ACPI signals, which it may not be able to do in the sort of 4234 situations where the watchdog would have expired, and thus 4235 ``-watchdog-action shutdown`` is not recommended for production use. 4236 4237 Examples: 4238 4239 ``-watchdog i6300esb -watchdog-action pause``; \ ``-watchdog ib700`` 4240 4241ERST 4242 4243DEF("echr", HAS_ARG, QEMU_OPTION_echr, \ 4244 "-echr chr set terminal escape character instead of ctrl-a\n", 4245 QEMU_ARCH_ALL) 4246SRST 4247``-echr numeric_ascii_value`` 4248 Change the escape character used for switching to the monitor when 4249 using monitor and serial sharing. The default is ``0x01`` when using 4250 the ``-nographic`` option. ``0x01`` is equal to pressing 4251 ``Control-a``. You can select a different character from the ascii 4252 control keys where 1 through 26 map to Control-a through Control-z. 4253 For instance you could use the either of the following to change the 4254 escape character to Control-t. 4255 4256 ``-echr 0x14``; \ ``-echr 20`` 4257 4258ERST 4259 4260DEF("incoming", HAS_ARG, QEMU_OPTION_incoming, \ 4261 "-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]\n" \ 4262 "-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]\n" \ 4263 "-incoming unix:socketpath\n" \ 4264 " prepare for incoming migration, listen on\n" \ 4265 " specified protocol and socket address\n" \ 4266 "-incoming fd:fd\n" \ 4267 "-incoming exec:cmdline\n" \ 4268 " accept incoming migration on given file descriptor\n" \ 4269 " or from given external command\n" \ 4270 "-incoming defer\n" \ 4271 " wait for the URI to be specified via migrate_incoming\n", 4272 QEMU_ARCH_ALL) 4273SRST 4274``-incoming tcp:[host]:port[,to=maxport][,ipv4=on|off][,ipv6=on|off]`` 4275 \ 4276``-incoming rdma:host:port[,ipv4=on|off][,ipv6=on|off]`` 4277 Prepare for incoming migration, listen on a given tcp port. 4278 4279``-incoming unix:socketpath`` 4280 Prepare for incoming migration, listen on a given unix socket. 4281 4282``-incoming fd:fd`` 4283 Accept incoming migration from a given filedescriptor. 4284 4285``-incoming exec:cmdline`` 4286 Accept incoming migration as an output from specified external 4287 command. 4288 4289``-incoming defer`` 4290 Wait for the URI to be specified via migrate\_incoming. The monitor 4291 can be used to change settings (such as migration parameters) prior 4292 to issuing the migrate\_incoming to allow the migration to begin. 4293ERST 4294 4295DEF("only-migratable", 0, QEMU_OPTION_only_migratable, \ 4296 "-only-migratable allow only migratable devices\n", QEMU_ARCH_ALL) 4297SRST 4298``-only-migratable`` 4299 Only allow migratable devices. Devices will not be allowed to enter 4300 an unmigratable state. 4301ERST 4302 4303DEF("nodefaults", 0, QEMU_OPTION_nodefaults, \ 4304 "-nodefaults don't create default devices\n", QEMU_ARCH_ALL) 4305SRST 4306``-nodefaults`` 4307 Don't create default devices. Normally, QEMU sets the default 4308 devices like serial port, parallel port, virtual console, monitor 4309 device, VGA adapter, floppy and CD-ROM drive and others. The 4310 ``-nodefaults`` option will disable all those default devices. 4311ERST 4312 4313#ifndef _WIN32 4314DEF("chroot", HAS_ARG, QEMU_OPTION_chroot, \ 4315 "-chroot dir chroot to dir just before starting the VM\n", 4316 QEMU_ARCH_ALL) 4317#endif 4318SRST 4319``-chroot dir`` 4320 Immediately before starting guest execution, chroot to the specified 4321 directory. Especially useful in combination with -runas. 4322ERST 4323 4324#ifndef _WIN32 4325DEF("runas", HAS_ARG, QEMU_OPTION_runas, \ 4326 "-runas user change to user id user just before starting the VM\n" \ 4327 " user can be numeric uid:gid instead\n", 4328 QEMU_ARCH_ALL) 4329#endif 4330SRST 4331``-runas user`` 4332 Immediately before starting guest execution, drop root privileges, 4333 switching to the specified user. 4334ERST 4335 4336DEF("prom-env", HAS_ARG, QEMU_OPTION_prom_env, 4337 "-prom-env variable=value\n" 4338 " set OpenBIOS nvram variables\n", 4339 QEMU_ARCH_PPC | QEMU_ARCH_SPARC) 4340SRST 4341``-prom-env variable=value`` 4342 Set OpenBIOS nvram variable to given value (PPC, SPARC only). 4343 4344 :: 4345 4346 qemu-system-sparc -prom-env 'auto-boot?=false' \ 4347 -prom-env 'boot-device=sd(0,2,0):d' -prom-env 'boot-args=linux single' 4348 4349 :: 4350 4351 qemu-system-ppc -prom-env 'auto-boot?=false' \ 4352 -prom-env 'boot-device=hd:2,\yaboot' \ 4353 -prom-env 'boot-args=conf=hd:2,\yaboot.conf' 4354ERST 4355DEF("semihosting", 0, QEMU_OPTION_semihosting, 4356 "-semihosting semihosting mode\n", 4357 QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4358 QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4359SRST 4360``-semihosting`` 4361 Enable semihosting mode (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V only). 4362 4363 Note that this allows guest direct access to the host filesystem, so 4364 should only be used with a trusted guest OS. 4365 4366 See the -semihosting-config option documentation for further 4367 information about the facilities this enables. 4368ERST 4369DEF("semihosting-config", HAS_ARG, QEMU_OPTION_semihosting_config, 4370 "-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]\n" \ 4371 " semihosting configuration\n", 4372QEMU_ARCH_ARM | QEMU_ARCH_M68K | QEMU_ARCH_XTENSA | 4373QEMU_ARCH_MIPS | QEMU_ARCH_NIOS2 | QEMU_ARCH_RISCV) 4374SRST 4375``-semihosting-config [enable=on|off][,target=native|gdb|auto][,chardev=id][,arg=str[,...]]`` 4376 Enable and configure semihosting (ARM, M68K, Xtensa, MIPS, Nios II, RISC-V 4377 only). 4378 4379 Note that this allows guest direct access to the host filesystem, so 4380 should only be used with a trusted guest OS. 4381 4382 On Arm this implements the standard semihosting API, version 2.0. 4383 4384 On M68K this implements the "ColdFire GDB" interface used by 4385 libgloss. 4386 4387 Xtensa semihosting provides basic file IO calls, such as 4388 open/read/write/seek/select. Tensilica baremetal libc for ISS and 4389 linux platform "sim" use this interface. 4390 4391 On RISC-V this implements the standard semihosting API, version 0.2. 4392 4393 ``target=native|gdb|auto`` 4394 Defines where the semihosting calls will be addressed, to QEMU 4395 (``native``) or to GDB (``gdb``). The default is ``auto``, which 4396 means ``gdb`` during debug sessions and ``native`` otherwise. 4397 4398 ``chardev=str1`` 4399 Send the output to a chardev backend output for native or auto 4400 output when not in gdb 4401 4402 ``arg=str1,arg=str2,...`` 4403 Allows the user to pass input arguments, and can be used 4404 multiple times to build up a list. The old-style 4405 ``-kernel``/``-append`` method of passing a command line is 4406 still supported for backward compatibility. If both the 4407 ``--semihosting-config arg`` and the ``-kernel``/``-append`` are 4408 specified, the former is passed to semihosting as it always 4409 takes precedence. 4410ERST 4411DEF("old-param", 0, QEMU_OPTION_old_param, 4412 "-old-param old param mode\n", QEMU_ARCH_ARM) 4413SRST 4414``-old-param`` 4415 Old param mode (ARM only). 4416ERST 4417 4418DEF("sandbox", HAS_ARG, QEMU_OPTION_sandbox, \ 4419 "-sandbox on[,obsolete=allow|deny][,elevateprivileges=allow|deny|children]\n" \ 4420 " [,spawn=allow|deny][,resourcecontrol=allow|deny]\n" \ 4421 " Enable seccomp mode 2 system call filter (default 'off').\n" \ 4422 " use 'obsolete' to allow obsolete system calls that are provided\n" \ 4423 " by the kernel, but typically no longer used by modern\n" \ 4424 " C library implementations.\n" \ 4425 " use 'elevateprivileges' to allow or deny the QEMU process ability\n" \ 4426 " to elevate privileges using set*uid|gid system calls.\n" \ 4427 " The value 'children' will deny set*uid|gid system calls for\n" \ 4428 " main QEMU process but will allow forks and execves to run unprivileged\n" \ 4429 " use 'spawn' to avoid QEMU to spawn new threads or processes by\n" \ 4430 " blocking *fork and execve\n" \ 4431 " use 'resourcecontrol' to disable process affinity and schedular priority\n", 4432 QEMU_ARCH_ALL) 4433SRST 4434``-sandbox arg[,obsolete=string][,elevateprivileges=string][,spawn=string][,resourcecontrol=string]`` 4435 Enable Seccomp mode 2 system call filter. 'on' will enable syscall 4436 filtering and 'off' will disable it. The default is 'off'. 4437 4438 ``obsolete=string`` 4439 Enable Obsolete system calls 4440 4441 ``elevateprivileges=string`` 4442 Disable set\*uid\|gid system calls 4443 4444 ``spawn=string`` 4445 Disable \*fork and execve 4446 4447 ``resourcecontrol=string`` 4448 Disable process affinity and schedular priority 4449ERST 4450 4451DEF("readconfig", HAS_ARG, QEMU_OPTION_readconfig, 4452 "-readconfig <file>\n", QEMU_ARCH_ALL) 4453SRST 4454``-readconfig file`` 4455 Read device configuration from file. This approach is useful when 4456 you want to spawn QEMU process with many command line options but 4457 you don't want to exceed the command line character limit. 4458ERST 4459DEF("writeconfig", HAS_ARG, QEMU_OPTION_writeconfig, 4460 "-writeconfig <file>\n" 4461 " read/write config file (deprecated)\n", QEMU_ARCH_ALL) 4462SRST 4463ERST 4464 4465DEF("no-user-config", 0, QEMU_OPTION_nouserconfig, 4466 "-no-user-config\n" 4467 " do not load default user-provided config files at startup\n", 4468 QEMU_ARCH_ALL) 4469SRST 4470``-no-user-config`` 4471 The ``-no-user-config`` option makes QEMU not load any of the 4472 user-provided config files on sysconfdir. 4473ERST 4474 4475DEF("trace", HAS_ARG, QEMU_OPTION_trace, 4476 "-trace [[enable=]<pattern>][,events=<file>][,file=<file>]\n" 4477 " specify tracing options\n", 4478 QEMU_ARCH_ALL) 4479SRST 4480``-trace [[enable=]pattern][,events=file][,file=file]`` 4481 .. include:: ../qemu-option-trace.rst.inc 4482 4483ERST 4484DEF("plugin", HAS_ARG, QEMU_OPTION_plugin, 4485 "-plugin [file=]<file>[,arg=<string>]\n" 4486 " load a plugin\n", 4487 QEMU_ARCH_ALL) 4488SRST 4489``-plugin file=file[,arg=string]`` 4490 Load a plugin. 4491 4492 ``file=file`` 4493 Load the given plugin from a shared library file. 4494 4495 ``arg=string`` 4496 Argument string passed to the plugin. (Can be given multiple 4497 times.) 4498ERST 4499 4500HXCOMM Internal use 4501DEF("qtest", HAS_ARG, QEMU_OPTION_qtest, "", QEMU_ARCH_ALL) 4502DEF("qtest-log", HAS_ARG, QEMU_OPTION_qtest_log, "", QEMU_ARCH_ALL) 4503 4504#ifdef __linux__ 4505DEF("enable-fips", 0, QEMU_OPTION_enablefips, 4506 "-enable-fips enable FIPS 140-2 compliance\n", 4507 QEMU_ARCH_ALL) 4508#endif 4509SRST 4510``-enable-fips`` 4511 Enable FIPS 140-2 compliance mode. 4512ERST 4513 4514DEF("msg", HAS_ARG, QEMU_OPTION_msg, 4515 "-msg [timestamp[=on|off]][,guest-name=[on|off]]\n" 4516 " control error message format\n" 4517 " timestamp=on enables timestamps (default: off)\n" 4518 " guest-name=on enables guest name prefix but only if\n" 4519 " -name guest option is set (default: off)\n", 4520 QEMU_ARCH_ALL) 4521SRST 4522``-msg [timestamp[=on|off]][,guest-name[=on|off]]`` 4523 Control error message format. 4524 4525 ``timestamp=on|off`` 4526 Prefix messages with a timestamp. Default is off. 4527 4528 ``guest-name=on|off`` 4529 Prefix messages with guest name but only if -name guest option is set 4530 otherwise the option is ignored. Default is off. 4531ERST 4532 4533DEF("dump-vmstate", HAS_ARG, QEMU_OPTION_dump_vmstate, 4534 "-dump-vmstate <file>\n" 4535 " Output vmstate information in JSON format to file.\n" 4536 " Use the scripts/vmstate-static-checker.py file to\n" 4537 " check for possible regressions in migration code\n" 4538 " by comparing two such vmstate dumps.\n", 4539 QEMU_ARCH_ALL) 4540SRST 4541``-dump-vmstate file`` 4542 Dump json-encoded vmstate information for current machine type to 4543 file in file 4544ERST 4545 4546DEF("enable-sync-profile", 0, QEMU_OPTION_enable_sync_profile, 4547 "-enable-sync-profile\n" 4548 " enable synchronization profiling\n", 4549 QEMU_ARCH_ALL) 4550SRST 4551``-enable-sync-profile`` 4552 Enable synchronization profiling. 4553ERST 4554 4555DEFHEADING() 4556 4557DEFHEADING(Generic object creation:) 4558 4559DEF("object", HAS_ARG, QEMU_OPTION_object, 4560 "-object TYPENAME[,PROP1=VALUE1,...]\n" 4561 " create a new object of type TYPENAME setting properties\n" 4562 " in the order they are specified. Note that the 'id'\n" 4563 " property must be set. These objects are placed in the\n" 4564 " '/objects' path.\n", 4565 QEMU_ARCH_ALL) 4566SRST 4567``-object typename[,prop1=value1,...]`` 4568 Create a new object of type typename setting properties in the order 4569 they are specified. Note that the 'id' property must be set. These 4570 objects are placed in the '/objects' path. 4571 4572 ``-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`` 4573 Creates a memory file backend object, which can be used to back 4574 the guest RAM with huge pages. 4575 4576 The ``id`` parameter is a unique ID that will be used to 4577 reference this memory region in other parameters, e.g. ``-numa``, 4578 ``-device nvdimm``, etc. 4579 4580 The ``size`` option provides the size of the memory region, and 4581 accepts common suffixes, e.g. ``500M``. 4582 4583 The ``mem-path`` provides the path to either a shared memory or 4584 huge page filesystem mount. 4585 4586 The ``share`` boolean option determines whether the memory 4587 region is marked as private to QEMU, or shared. The latter 4588 allows a co-operating external process to access the QEMU memory 4589 region. 4590 4591 The ``share`` is also required for pvrdma devices due to 4592 limitations in the RDMA API provided by Linux. 4593 4594 Setting share=on might affect the ability to configure NUMA 4595 bindings for the memory backend under some circumstances, see 4596 Documentation/vm/numa\_memory\_policy.txt on the Linux kernel 4597 source tree for additional details. 4598 4599 Setting the ``discard-data`` boolean option to on indicates that 4600 file contents can be destroyed when QEMU exits, to avoid 4601 unnecessarily flushing data to the backing file. Note that 4602 ``discard-data`` is only an optimization, and QEMU might not 4603 discard file contents if it aborts unexpectedly or is terminated 4604 using SIGKILL. 4605 4606 The ``merge`` boolean option enables memory merge, also known as 4607 MADV\_MERGEABLE, so that Kernel Samepage Merging will consider 4608 the pages for memory deduplication. 4609 4610 Setting the ``dump`` boolean option to off excludes the memory 4611 from core dumps. This feature is also known as MADV\_DONTDUMP. 4612 4613 The ``prealloc`` boolean option enables memory preallocation. 4614 4615 The ``host-nodes`` option binds the memory range to a list of 4616 NUMA host nodes. 4617 4618 The ``policy`` option sets the NUMA policy to one of the 4619 following values: 4620 4621 ``default`` 4622 default host policy 4623 4624 ``preferred`` 4625 prefer the given host node list for allocation 4626 4627 ``bind`` 4628 restrict memory allocation to the given host node list 4629 4630 ``interleave`` 4631 interleave memory allocations across the given host node 4632 list 4633 4634 The ``align`` option specifies the base address alignment when 4635 QEMU mmap(2) ``mem-path``, and accepts common suffixes, eg 4636 ``2M``. Some backend store specified by ``mem-path`` requires an 4637 alignment different than the default one used by QEMU, eg the 4638 device DAX /dev/dax0.0 requires 2M alignment rather than 4K. In 4639 such cases, users can specify the required alignment via this 4640 option. 4641 4642 The ``pmem`` option specifies whether the backing file specified 4643 by ``mem-path`` is in host persistent memory that can be 4644 accessed using the SNIA NVM programming model (e.g. Intel 4645 NVDIMM). If ``pmem`` is set to 'on', QEMU will take necessary 4646 operations to guarantee the persistence of its own writes to 4647 ``mem-path`` (e.g. in vNVDIMM label emulation and live 4648 migration). Also, we will map the backend-file with MAP\_SYNC 4649 flag, which ensures the file metadata is in sync for 4650 ``mem-path`` in case of host crash or a power failure. MAP\_SYNC 4651 requires support from both the host kernel (since Linux kernel 4652 4.15) and the filesystem of ``mem-path`` mounted with DAX 4653 option. 4654 4655 The ``readonly`` option specifies whether the backing file is opened 4656 read-only or read-write (default). 4657 4658 ``-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`` 4659 Creates a memory backend object, which can be used to back the 4660 guest RAM. Memory backend objects offer more control than the 4661 ``-m`` option that is traditionally used to define guest RAM. 4662 Please refer to ``memory-backend-file`` for a description of the 4663 options. 4664 4665 ``-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`` 4666 Creates an anonymous memory file backend object, which allows 4667 QEMU to share the memory with an external process (e.g. when 4668 using vhost-user). The memory is allocated with memfd and 4669 optional sealing. (Linux only) 4670 4671 The ``seal`` option creates a sealed-file, that will block 4672 further resizing the memory ('on' by default). 4673 4674 The ``hugetlb`` option specify the file to be created resides in 4675 the hugetlbfs filesystem (since Linux 4.14). Used in conjunction 4676 with the ``hugetlb`` option, the ``hugetlbsize`` option specify 4677 the hugetlb page size on systems that support multiple hugetlb 4678 page sizes (it must be a power of 2 value supported by the 4679 system). 4680 4681 In some versions of Linux, the ``hugetlb`` option is 4682 incompatible with the ``seal`` option (requires at least Linux 4683 4.16). 4684 4685 Please refer to ``memory-backend-file`` for a description of the 4686 other options. 4687 4688 The ``share`` boolean option is on by default with memfd. 4689 4690 ``-object rng-builtin,id=id`` 4691 Creates a random number generator backend which obtains entropy 4692 from QEMU builtin functions. The ``id`` parameter is a unique ID 4693 that will be used to reference this entropy backend from the 4694 ``virtio-rng`` device. By default, the ``virtio-rng`` device 4695 uses this RNG backend. 4696 4697 ``-object rng-random,id=id,filename=/dev/random`` 4698 Creates a random number generator backend which obtains entropy 4699 from a device on the host. The ``id`` parameter is a unique ID 4700 that will be used to reference this entropy backend from the 4701 ``virtio-rng`` device. The ``filename`` parameter specifies 4702 which file to obtain entropy from and if omitted defaults to 4703 ``/dev/urandom``. 4704 4705 ``-object rng-egd,id=id,chardev=chardevid`` 4706 Creates a random number generator backend which obtains entropy 4707 from an external daemon running on the host. The ``id`` 4708 parameter is a unique ID that will be used to reference this 4709 entropy backend from the ``virtio-rng`` device. The ``chardev`` 4710 parameter is the unique ID of a character device backend that 4711 provides the connection to the RNG daemon. 4712 4713 ``-object tls-creds-anon,id=id,endpoint=endpoint,dir=/path/to/cred/dir,verify-peer=on|off`` 4714 Creates a TLS anonymous credentials object, which can be used to 4715 provide TLS support on network backends. The ``id`` parameter is 4716 a unique ID which network backends will use to access the 4717 credentials. The ``endpoint`` is either ``server`` or ``client`` 4718 depending on whether the QEMU network backend that uses the 4719 credentials will be acting as a client or as a server. If 4720 ``verify-peer`` is enabled (the default) then once the handshake 4721 is completed, the peer credentials will be verified, though this 4722 is a no-op for anonymous credentials. 4723 4724 The dir parameter tells QEMU where to find the credential files. 4725 For server endpoints, this directory may contain a file 4726 dh-params.pem providing diffie-hellman parameters to use for the 4727 TLS server. If the file is missing, QEMU will generate a set of 4728 DH parameters at startup. This is a computationally expensive 4729 operation that consumes random pool entropy, so it is 4730 recommended that a persistent set of parameters be generated 4731 upfront and saved. 4732 4733 ``-object tls-creds-psk,id=id,endpoint=endpoint,dir=/path/to/keys/dir[,username=username]`` 4734 Creates a TLS Pre-Shared Keys (PSK) credentials object, which 4735 can be used to provide TLS support on network backends. The 4736 ``id`` parameter is a unique ID which network backends will use 4737 to access the credentials. The ``endpoint`` is either ``server`` 4738 or ``client`` depending on whether the QEMU network backend that 4739 uses the credentials will be acting as a client or as a server. 4740 For clients only, ``username`` is the username which will be 4741 sent to the server. If omitted it defaults to "qemu". 4742 4743 The dir parameter tells QEMU where to find the keys file. It is 4744 called "dir/keys.psk" and contains "username:key" pairs. This 4745 file can most easily be created using the GnuTLS ``psktool`` 4746 program. 4747 4748 For server endpoints, dir may also contain a file dh-params.pem 4749 providing diffie-hellman parameters to use for the TLS server. 4750 If the file is missing, QEMU will generate a set of DH 4751 parameters at startup. This is a computationally expensive 4752 operation that consumes random pool entropy, so it is 4753 recommended that a persistent set of parameters be generated up 4754 front and saved. 4755 4756 ``-object tls-creds-x509,id=id,endpoint=endpoint,dir=/path/to/cred/dir,priority=priority,verify-peer=on|off,passwordid=id`` 4757 Creates a TLS anonymous credentials object, which can be used to 4758 provide TLS support on network backends. The ``id`` parameter is 4759 a unique ID which network backends will use to access the 4760 credentials. The ``endpoint`` is either ``server`` or ``client`` 4761 depending on whether the QEMU network backend that uses the 4762 credentials will be acting as a client or as a server. If 4763 ``verify-peer`` is enabled (the default) then once the handshake 4764 is completed, the peer credentials will be verified. With x509 4765 certificates, this implies that the clients must be provided 4766 with valid client certificates too. 4767 4768 The dir parameter tells QEMU where to find the credential files. 4769 For server endpoints, this directory may contain a file 4770 dh-params.pem providing diffie-hellman parameters to use for the 4771 TLS server. If the file is missing, QEMU will generate a set of 4772 DH parameters at startup. This is a computationally expensive 4773 operation that consumes random pool entropy, so it is 4774 recommended that a persistent set of parameters be generated 4775 upfront and saved. 4776 4777 For x509 certificate credentials the directory will contain 4778 further files providing the x509 certificates. The certificates 4779 must be stored in PEM format, in filenames ca-cert.pem, 4780 ca-crl.pem (optional), server-cert.pem (only servers), 4781 server-key.pem (only servers), client-cert.pem (only clients), 4782 and client-key.pem (only clients). 4783 4784 For the server-key.pem and client-key.pem files which contain 4785 sensitive private keys, it is possible to use an encrypted 4786 version by providing the passwordid parameter. This provides the 4787 ID of a previously created ``secret`` object containing the 4788 password for decryption. 4789 4790 The priority parameter allows to override the global default 4791 priority used by gnutls. This can be useful if the system 4792 administrator needs to use a weaker set of crypto priorities for 4793 QEMU without potentially forcing the weakness onto all 4794 applications. Or conversely if one wants wants a stronger 4795 default for QEMU than for all other applications, they can do 4796 this through this parameter. Its format is a gnutls priority 4797 string as described at 4798 https://gnutls.org/manual/html_node/Priority-Strings.html. 4799 4800 ``-object tls-cipher-suites,id=id,priority=priority`` 4801 Creates a TLS cipher suites object, which can be used to control 4802 the TLS cipher/protocol algorithms that applications are permitted 4803 to use. 4804 4805 The ``id`` parameter is a unique ID which frontends will use to 4806 access the ordered list of permitted TLS cipher suites from the 4807 host. 4808 4809 The ``priority`` parameter allows to override the global default 4810 priority used by gnutls. This can be useful if the system 4811 administrator needs to use a weaker set of crypto priorities for 4812 QEMU without potentially forcing the weakness onto all 4813 applications. Or conversely if one wants wants a stronger 4814 default for QEMU than for all other applications, they can do 4815 this through this parameter. Its format is a gnutls priority 4816 string as described at 4817 https://gnutls.org/manual/html_node/Priority-Strings.html. 4818 4819 An example of use of this object is to control UEFI HTTPS Boot. 4820 The tls-cipher-suites object exposes the ordered list of permitted 4821 TLS cipher suites from the host side to the guest firmware, via 4822 fw_cfg. The list is represented as an array of IANA_TLS_CIPHER 4823 objects. The firmware uses the IANA_TLS_CIPHER array for configuring 4824 guest-side TLS. 4825 4826 In the following example, the priority at which the host-side policy 4827 is retrieved is given by the ``priority`` property. 4828 Given that QEMU uses GNUTLS, ``priority=@SYSTEM`` may be used to 4829 refer to /etc/crypto-policies/back-ends/gnutls.config. 4830 4831 .. parsed-literal:: 4832 4833 # |qemu_system| \\ 4834 -object tls-cipher-suites,id=mysuite0,priority=@SYSTEM \\ 4835 -fw_cfg name=etc/edk2/https/ciphers,gen_id=mysuite0 4836 4837 ``-object filter-buffer,id=id,netdev=netdevid,interval=t[,queue=all|rx|tx][,status=on|off][,position=head|tail|id=<id>][,insert=behind|before]`` 4838 Interval t can't be 0, this filter batches the packet delivery: 4839 all packets arriving in a given interval on netdev netdevid are 4840 delayed until the end of the interval. Interval is in 4841 microseconds. ``status`` is optional that indicate whether the 4842 netfilter is on (enabled) or off (disabled), the default status 4843 for netfilter will be 'on'. 4844 4845 queue all\|rx\|tx is an option that can be applied to any 4846 netfilter. 4847 4848 ``all``: the filter is attached both to the receive and the 4849 transmit queue of the netdev (default). 4850 4851 ``rx``: the filter is attached to the receive queue of the 4852 netdev, where it will receive packets sent to the netdev. 4853 4854 ``tx``: the filter is attached to the transmit queue of the 4855 netdev, where it will receive packets sent by the netdev. 4856 4857 position head\|tail\|id=<id> is an option to specify where the 4858 filter should be inserted in the filter list. It can be applied 4859 to any netfilter. 4860 4861 ``head``: the filter is inserted at the head of the filter list, 4862 before any existing filters. 4863 4864 ``tail``: the filter is inserted at the tail of the filter list, 4865 behind any existing filters (default). 4866 4867 ``id=<id>``: the filter is inserted before or behind the filter 4868 specified by <id>, see the insert option below. 4869 4870 insert behind\|before is an option to specify where to insert 4871 the new filter relative to the one specified with 4872 position=id=<id>. It can be applied to any netfilter. 4873 4874 ``before``: insert before the specified filter. 4875 4876 ``behind``: insert behind the specified filter (default). 4877 4878 ``-object filter-mirror,id=id,netdev=netdevid,outdev=chardevid,queue=all|rx|tx[,vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4879 filter-mirror on netdev netdevid,mirror net packet to 4880 chardevchardevid, if it has the vnet\_hdr\_support flag, 4881 filter-mirror will mirror packet with vnet\_hdr\_len. 4882 4883 ``-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]`` 4884 filter-redirector on netdev netdevid,redirect filter's net 4885 packet to chardev chardevid,and redirect indev's packet to 4886 filter.if it has the vnet\_hdr\_support flag, filter-redirector 4887 will redirect packet with vnet\_hdr\_len. Create a 4888 filter-redirector we need to differ outdev id from indev id, id 4889 can not be the same. we can just use indev or outdev, but at 4890 least one of indev or outdev need to be specified. 4891 4892 ``-object filter-rewriter,id=id,netdev=netdevid,queue=all|rx|tx,[vnet_hdr_support][,position=head|tail|id=<id>][,insert=behind|before]`` 4893 Filter-rewriter is a part of COLO project.It will rewrite tcp 4894 packet to secondary from primary to keep secondary tcp 4895 connection,and rewrite tcp packet to primary from secondary make 4896 tcp packet can be handled by client.if it has the 4897 vnet\_hdr\_support flag, we can parse packet with vnet header. 4898 4899 usage: colo secondary: -object 4900 filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 -object 4901 filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 -object 4902 filter-rewriter,id=rew0,netdev=hn0,queue=all 4903 4904 ``-object filter-dump,id=id,netdev=dev[,file=filename][,maxlen=len][,position=head|tail|id=<id>][,insert=behind|before]`` 4905 Dump the network traffic on netdev dev to the file specified by 4906 filename. At most len bytes (64k by default) per packet are 4907 stored. The file format is libpcap, so it can be analyzed with 4908 tools such as tcpdump or Wireshark. 4909 4910 ``-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}]`` 4911 Colo-compare gets packet from primary\_in chardevid and 4912 secondary\_in, then compare whether the payload of primary packet 4913 and secondary packet are the same. If same, it will output 4914 primary packet to out\_dev, else it will notify COLO-framework to do 4915 checkpoint and send primary packet to out\_dev. In order to 4916 improve efficiency, we need to put the task of comparison in 4917 another iothread. If it has the vnet\_hdr\_support flag, 4918 colo compare will send/recv packet with vnet\_hdr\_len. 4919 The compare\_timeout=@var{ms} determines the maximum time of the 4920 colo-compare hold the packet. The expired\_scan\_cycle=@var{ms} 4921 is to set the period of scanning expired primary node network packets. 4922 The max\_queue\_size=@var{size} is to set the max compare queue 4923 size depend on user environment. 4924 If user want to use Xen COLO, need to add the notify\_dev to 4925 notify Xen colo-frame to do checkpoint. 4926 4927 COLO-compare must be used with the help of filter-mirror, 4928 filter-redirector and filter-rewriter. 4929 4930 :: 4931 4932 KVM COLO 4933 4934 primary: 4935 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4936 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4937 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 4938 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 4939 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 4940 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4941 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 4942 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4943 -object iothread,id=iothread1 4944 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4945 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4946 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4947 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,iothread=iothread1 4948 4949 secondary: 4950 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4951 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4952 -chardev socket,id=red0,host=3.3.3.3,port=9003 4953 -chardev socket,id=red1,host=3.3.3.3,port=9004 4954 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4955 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4956 4957 4958 Xen COLO 4959 4960 primary: 4961 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,downscript=/etc/qemu-ifdown 4962 -device e1000,id=e0,netdev=hn0,mac=52:a4:00:12:78:66 4963 -chardev socket,id=mirror0,host=3.3.3.3,port=9003,server=on,wait=off 4964 -chardev socket,id=compare1,host=3.3.3.3,port=9004,server=on,wait=off 4965 -chardev socket,id=compare0,host=3.3.3.3,port=9001,server=on,wait=off 4966 -chardev socket,id=compare0-0,host=3.3.3.3,port=9001 4967 -chardev socket,id=compare_out,host=3.3.3.3,port=9005,server=on,wait=off 4968 -chardev socket,id=compare_out0,host=3.3.3.3,port=9005 4969 -chardev socket,id=notify_way,host=3.3.3.3,port=9009,server=on,wait=off 4970 -object filter-mirror,id=m0,netdev=hn0,queue=tx,outdev=mirror0 4971 -object filter-redirector,netdev=hn0,id=redire0,queue=rx,indev=compare_out 4972 -object filter-redirector,netdev=hn0,id=redire1,queue=rx,outdev=compare0 4973 -object iothread,id=iothread1 4974 -object colo-compare,id=comp0,primary_in=compare0-0,secondary_in=compare1,outdev=compare_out0,notify_dev=nofity_way,iothread=iothread1 4975 4976 secondary: 4977 -netdev tap,id=hn0,vhost=off,script=/etc/qemu-ifup,down script=/etc/qemu-ifdown 4978 -device e1000,netdev=hn0,mac=52:a4:00:12:78:66 4979 -chardev socket,id=red0,host=3.3.3.3,port=9003 4980 -chardev socket,id=red1,host=3.3.3.3,port=9004 4981 -object filter-redirector,id=f1,netdev=hn0,queue=tx,indev=red0 4982 -object filter-redirector,id=f2,netdev=hn0,queue=rx,outdev=red1 4983 4984 If you want to know the detail of above command line, you can 4985 read the colo-compare git log. 4986 4987 ``-object cryptodev-backend-builtin,id=id[,queues=queues]`` 4988 Creates a cryptodev backend which executes crypto opreation from 4989 the QEMU cipher APIS. The id parameter is a unique ID that will 4990 be used to reference this cryptodev backend from the 4991 ``virtio-crypto`` device. The queues parameter is optional, 4992 which specify the queue number of cryptodev backend, the default 4993 of queues is 1. 4994 4995 .. parsed-literal:: 4996 4997 # |qemu_system| \\ 4998 [...] \\ 4999 -object cryptodev-backend-builtin,id=cryptodev0 \\ 5000 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5001 [...] 5002 5003 ``-object cryptodev-vhost-user,id=id,chardev=chardevid[,queues=queues]`` 5004 Creates a vhost-user cryptodev backend, backed by a chardev 5005 chardevid. The id parameter is a unique ID that will be used to 5006 reference this cryptodev backend from the ``virtio-crypto`` 5007 device. The chardev should be a unix domain socket backed one. 5008 The vhost-user uses a specifically defined protocol to pass 5009 vhost ioctl replacement messages to an application on the other 5010 end of the socket. The queues parameter is optional, which 5011 specify the queue number of cryptodev backend for multiqueue 5012 vhost-user, the default of queues is 1. 5013 5014 .. parsed-literal:: 5015 5016 # |qemu_system| \\ 5017 [...] \\ 5018 -chardev socket,id=chardev0,path=/path/to/socket \\ 5019 -object cryptodev-vhost-user,id=cryptodev0,chardev=chardev0 \\ 5020 -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0 \\ 5021 [...] 5022 5023 ``-object secret,id=id,data=string,format=raw|base64[,keyid=secretid,iv=string]`` 5024 \ 5025 ``-object secret,id=id,file=filename,format=raw|base64[,keyid=secretid,iv=string]`` 5026 Defines a secret to store a password, encryption key, or some 5027 other sensitive data. The sensitive data can either be passed 5028 directly via the data parameter, or indirectly via the file 5029 parameter. Using the data parameter is insecure unless the 5030 sensitive data is encrypted. 5031 5032 The sensitive data can be provided in raw format (the default), 5033 or base64. When encoded as JSON, the raw format only supports 5034 valid UTF-8 characters, so base64 is recommended for sending 5035 binary data. QEMU will convert from which ever format is 5036 provided to the format it needs internally. eg, an RBD password 5037 can be provided in raw format, even though it will be base64 5038 encoded when passed onto the RBD sever. 5039 5040 For added protection, it is possible to encrypt the data 5041 associated with a secret using the AES-256-CBC cipher. Use of 5042 encryption is indicated by providing the keyid and iv 5043 parameters. The keyid parameter provides the ID of a previously 5044 defined secret that contains the AES-256 decryption key. This 5045 key should be 32-bytes long and be base64 encoded. The iv 5046 parameter provides the random initialization vector used for 5047 encryption of this particular secret and should be a base64 5048 encrypted string of the 16-byte IV. 5049 5050 The simplest (insecure) usage is to provide the secret inline 5051 5052 .. parsed-literal:: 5053 5054 # |qemu_system| -object secret,id=sec0,data=letmein,format=raw 5055 5056 The simplest secure usage is to provide the secret via a file 5057 5058 # printf "letmein" > mypasswd.txt # QEMU\_SYSTEM\_MACRO -object 5059 secret,id=sec0,file=mypasswd.txt,format=raw 5060 5061 For greater security, AES-256-CBC should be used. To illustrate 5062 usage, consider the openssl command line tool which can encrypt 5063 the data. Note that when encrypting, the plaintext must be 5064 padded to the cipher block size (32 bytes) using the standard 5065 PKCS#5/6 compatible padding algorithm. 5066 5067 First a master key needs to be created in base64 encoding: 5068 5069 :: 5070 5071 # openssl rand -base64 32 > key.b64 5072 # KEY=$(base64 -d key.b64 | hexdump -v -e '/1 "%02X"') 5073 5074 Each secret to be encrypted needs to have a random 5075 initialization vector generated. These do not need to be kept 5076 secret 5077 5078 :: 5079 5080 # openssl rand -base64 16 > iv.b64 5081 # IV=$(base64 -d iv.b64 | hexdump -v -e '/1 "%02X"') 5082 5083 The secret to be defined can now be encrypted, in this case 5084 we're telling openssl to base64 encode the result, but it could 5085 be left as raw bytes if desired. 5086 5087 :: 5088 5089 # SECRET=$(printf "letmein" | 5090 openssl enc -aes-256-cbc -a -K $KEY -iv $IV) 5091 5092 When launching QEMU, create a master secret pointing to 5093 ``key.b64`` and specify that to be used to decrypt the user 5094 password. Pass the contents of ``iv.b64`` to the second secret 5095 5096 .. parsed-literal:: 5097 5098 # |qemu_system| \\ 5099 -object secret,id=secmaster0,format=base64,file=key.b64 \\ 5100 -object secret,id=sec0,keyid=secmaster0,format=base64,\\ 5101 data=$SECRET,iv=$(<iv.b64) 5102 5103 ``-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]`` 5104 Create a Secure Encrypted Virtualization (SEV) guest object, 5105 which can be used to provide the guest memory encryption support 5106 on AMD processors. 5107 5108 When memory encryption is enabled, one of the physical address 5109 bit (aka the C-bit) is utilized to mark if a memory page is 5110 protected. The ``cbitpos`` is used to provide the C-bit 5111 position. The C-bit position is Host family dependent hence user 5112 must provide this value. On EPYC, the value should be 47. 5113 5114 When memory encryption is enabled, we loose certain bits in 5115 physical address space. The ``reduced-phys-bits`` is used to 5116 provide the number of bits we loose in physical address space. 5117 Similar to C-bit, the value is Host family dependent. On EPYC, 5118 the value should be 5. 5119 5120 The ``sev-device`` provides the device file to use for 5121 communicating with the SEV firmware running inside AMD Secure 5122 Processor. The default device is '/dev/sev'. If hardware 5123 supports memory encryption then /dev/sev devices are created by 5124 CCP driver. 5125 5126 The ``policy`` provides the guest policy to be enforced by the 5127 SEV firmware and restrict what configuration and operational 5128 commands can be performed on this guest by the hypervisor. The 5129 policy should be provided by the guest owner and is bound to the 5130 guest and cannot be changed throughout the lifetime of the 5131 guest. The default is 0. 5132 5133 If guest ``policy`` allows sharing the key with another SEV 5134 guest then ``handle`` can be use to provide handle of the guest 5135 from which to share the key. 5136 5137 The ``dh-cert-file`` and ``session-file`` provides the guest 5138 owner's Public Diffie-Hillman key defined in SEV spec. The PDH 5139 and session parameters are used for establishing a cryptographic 5140 session with the guest owner to negotiate keys used for 5141 attestation. The file must be encoded in base64. 5142 5143 e.g to launch a SEV guest 5144 5145 .. parsed-literal:: 5146 5147 # |qemu_system_x86| \\ 5148 ...... \\ 5149 -object sev-guest,id=sev0,cbitpos=47,reduced-phys-bits=5 \\ 5150 -machine ...,memory-encryption=sev0 \\ 5151 ..... 5152 5153 ``-object authz-simple,id=id,identity=string`` 5154 Create an authorization object that will control access to 5155 network services. 5156 5157 The ``identity`` parameter is identifies the user and its format 5158 depends on the network service that authorization object is 5159 associated with. For authorizing based on TLS x509 certificates, 5160 the identity must be the x509 distinguished name. Note that care 5161 must be taken to escape any commas in the distinguished name. 5162 5163 An example authorization object to validate a x509 distinguished 5164 name would look like: 5165 5166 .. parsed-literal:: 5167 5168 # |qemu_system| \\ 5169 ... \\ 5170 -object 'authz-simple,id=auth0,identity=CN=laptop.example.com,,O=Example Org,,L=London,,ST=London,,C=GB' \\ 5171 ... 5172 5173 Note the use of quotes due to the x509 distinguished name 5174 containing whitespace, and escaping of ','. 5175 5176 ``-object authz-listfile,id=id,filename=path,refresh=on|off`` 5177 Create an authorization object that will control access to 5178 network services. 5179 5180 The ``filename`` parameter is the fully qualified path to a file 5181 containing the access control list rules in JSON format. 5182 5183 An example set of rules that match against SASL usernames might 5184 look like: 5185 5186 :: 5187 5188 { 5189 "rules": [ 5190 { "match": "fred", "policy": "allow", "format": "exact" }, 5191 { "match": "bob", "policy": "allow", "format": "exact" }, 5192 { "match": "danb", "policy": "deny", "format": "glob" }, 5193 { "match": "dan*", "policy": "allow", "format": "exact" }, 5194 ], 5195 "policy": "deny" 5196 } 5197 5198 When checking access the object will iterate over all the rules 5199 and the first rule to match will have its ``policy`` value 5200 returned as the result. If no rules match, then the default 5201 ``policy`` value is returned. 5202 5203 The rules can either be an exact string match, or they can use 5204 the simple UNIX glob pattern matching to allow wildcards to be 5205 used. 5206 5207 If ``refresh`` is set to true the file will be monitored and 5208 automatically reloaded whenever its content changes. 5209 5210 As with the ``authz-simple`` object, the format of the identity 5211 strings being matched depends on the network service, but is 5212 usually a TLS x509 distinguished name, or a SASL username. 5213 5214 An example authorization object to validate a SASL username 5215 would look like: 5216 5217 .. parsed-literal:: 5218 5219 # |qemu_system| \\ 5220 ... \\ 5221 -object authz-simple,id=auth0,filename=/etc/qemu/vnc-sasl.acl,refresh=on \\ 5222 ... 5223 5224 ``-object authz-pam,id=id,service=string`` 5225 Create an authorization object that will control access to 5226 network services. 5227 5228 The ``service`` parameter provides the name of a PAM service to 5229 use for authorization. It requires that a file 5230 ``/etc/pam.d/service`` exist to provide the configuration for 5231 the ``account`` subsystem. 5232 5233 An example authorization object to validate a TLS x509 5234 distinguished name would look like: 5235 5236 .. parsed-literal:: 5237 5238 # |qemu_system| \\ 5239 ... \\ 5240 -object authz-pam,id=auth0,service=qemu-vnc \\ 5241 ... 5242 5243 There would then be a corresponding config file for PAM at 5244 ``/etc/pam.d/qemu-vnc`` that contains: 5245 5246 :: 5247 5248 account requisite pam_listfile.so item=user sense=allow \ 5249 file=/etc/qemu/vnc.allow 5250 5251 Finally the ``/etc/qemu/vnc.allow`` file would contain the list 5252 of x509 distingished names that are permitted access 5253 5254 :: 5255 5256 CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB 5257 5258 ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink`` 5259 Creates a dedicated event loop thread that devices can be 5260 assigned to. This is known as an IOThread. By default device 5261 emulation happens in vCPU threads or the main event loop thread. 5262 This can become a scalability bottleneck. IOThreads allow device 5263 emulation and I/O to run on other host CPUs. 5264 5265 The ``id`` parameter is a unique ID that will be used to 5266 reference this IOThread from ``-device ...,iothread=id``. 5267 Multiple devices can be assigned to an IOThread. Note that not 5268 all devices support an ``iothread`` parameter. 5269 5270 The ``query-iothreads`` QMP command lists IOThreads and reports 5271 their thread IDs so that the user can configure host CPU 5272 pinning/affinity. 5273 5274 IOThreads use an adaptive polling algorithm to reduce event loop 5275 latency. Instead of entering a blocking system call to monitor 5276 file descriptors and then pay the cost of being woken up when an 5277 event occurs, the polling algorithm spins waiting for events for 5278 a short time. The algorithm's default parameters are suitable 5279 for many cases but can be adjusted based on knowledge of the 5280 workload and/or host device latency. 5281 5282 The ``poll-max-ns`` parameter is the maximum number of 5283 nanoseconds to busy wait for events. Polling can be disabled by 5284 setting this value to 0. 5285 5286 The ``poll-grow`` parameter is the multiplier used to increase 5287 the polling time when the algorithm detects it is missing events 5288 due to not polling long enough. 5289 5290 The ``poll-shrink`` parameter is the divisor used to decrease 5291 the polling time when the algorithm detects it is spending too 5292 long polling without encountering events. 5293 5294 The polling parameters can be modified at run-time using the 5295 ``qom-set`` command (where ``iothread1`` is the IOThread's 5296 ``id``): 5297 5298 :: 5299 5300 (qemu) qom-set /objects/iothread1 poll-max-ns 100000 5301ERST 5302 5303 5304HXCOMM This is the last statement. Insert new options before this line! 5305 5306#undef DEF 5307#undef DEFHEADING 5308#undef ARCHHEADING 5309
