1 /* 2 * Virtio PCI driver 3 * 4 * This module allows virtio devices to be used over a virtual PCI device. 5 * This can be used with QEMU based VMMs like KVM or Xen. 6 * 7 * Copyright IBM Corp. 2007 8 * 9 * Authors: 10 * Anthony Liguori <aliguori@us.ibm.com> 11 * 12 * This header is BSD licensed so anyone can use the definitions to implement 13 * compatible drivers/servers. 14 * 15 * Redistribution and use in source and binary forms, with or without 16 * modification, are permitted provided that the following conditions 17 * are met: 18 * 1. Redistributions of source code must retain the above copyright 19 * notice, this list of conditions and the following disclaimer. 20 * 2. Redistributions in binary form must reproduce the above copyright 21 * notice, this list of conditions and the following disclaimer in the 22 * documentation and/or other materials provided with the distribution. 23 * 3. Neither the name of IBM nor the names of its contributors 24 * may be used to endorse or promote products derived from this software 25 * without specific prior written permission. 26 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 */ 38 39 #ifndef _LINUX_VIRTIO_PCI_H 40 #define _LINUX_VIRTIO_PCI_H 41 42 #include "linux/types.h" 43 #include "linux/virtio_config.h" 44 45 #ifndef VIRTIO_PCI_NO_LEGACY 46 47 /* A 32-bit r/o bitmask of the features supported by the host */ 48 #define VIRTIO_PCI_HOST_FEATURES 0 49 50 /* A 32-bit r/w bitmask of features activated by the guest */ 51 #define VIRTIO_PCI_GUEST_FEATURES 4 52 53 /* A 32-bit r/w PFN for the currently selected queue */ 54 #define VIRTIO_PCI_QUEUE_PFN 8 55 56 /* A 16-bit r/o queue size for the currently selected queue */ 57 #define VIRTIO_PCI_QUEUE_NUM 12 58 59 /* A 16-bit r/w queue selector */ 60 #define VIRTIO_PCI_QUEUE_SEL 14 61 62 /* A 16-bit r/w queue notifier */ 63 #define VIRTIO_PCI_QUEUE_NOTIFY 16 64 65 /* An 8-bit device status register. */ 66 #define VIRTIO_PCI_STATUS 18 67 68 /* An 8-bit r/o interrupt status register. Reading the value will return the 69 * current contents of the ISR and will also clear it. This is effectively 70 * a read-and-acknowledge. */ 71 #define VIRTIO_PCI_ISR 19 72 73 /* MSI-X registers: only enabled if MSI-X is enabled. */ 74 /* A 16-bit vector for configuration changes. */ 75 #define VIRTIO_MSI_CONFIG_VECTOR 20 76 /* A 16-bit vector for selected queue notifications. */ 77 #define VIRTIO_MSI_QUEUE_VECTOR 22 78 79 /* The remaining space is defined by each driver as the per-driver 80 * configuration space */ 81 #define VIRTIO_PCI_CONFIG_OFF(msix_enabled) ((msix_enabled) ? 24 : 20) 82 /* Deprecated: please use VIRTIO_PCI_CONFIG_OFF instead */ 83 #define VIRTIO_PCI_CONFIG(msix_enabled) VIRTIO_PCI_CONFIG_OFF(msix_enabled) 84 85 /* How many bits to shift physical queue address written to QUEUE_PFN. 86 * 12 is historical, and due to x86 page size. */ 87 #define VIRTIO_PCI_QUEUE_ADDR_SHIFT 12 88 89 /* The alignment to use between consumer and producer parts of vring. 90 * x86 pagesize again. */ 91 #define VIRTIO_PCI_VRING_ALIGN 4096 92 93 #endif /* VIRTIO_PCI_NO_LEGACY */ 94 95 /* The bit of the ISR which indicates a device configuration change. */ 96 #define VIRTIO_PCI_ISR_CONFIG 0x2 97 /* Vector value used to disable MSI for queue */ 98 #define VIRTIO_MSI_NO_VECTOR 0xffff 99 100 /* IDs for different capabilities. Must all exist. */ 101 102 /* Common configuration */ 103 #define VIRTIO_PCI_CAP_COMMON_CFG 1 104 /* Notifications */ 105 #define VIRTIO_PCI_CAP_NOTIFY_CFG 2 106 /* ISR access */ 107 #define VIRTIO_PCI_CAP_ISR_CFG 3 108 /* Device specific configuration */ 109 #define VIRTIO_PCI_CAP_DEVICE_CFG 4 110 /* PCI configuration access */ 111 #define VIRTIO_PCI_CAP_PCI_CFG 5 112 113 /* This is the PCI capability header: */ 114 struct virtio_pci_cap { 115 __u8 cap_vndr; /* Generic PCI field: PCI_CAPABILITY_ID_VENDOR_SPECIFIC */ 116 __u8 cap_next; /* Generic PCI field: next ptr. */ 117 __u8 cap_len; /* Generic PCI field: capability length */ 118 __u8 cfg_type; /* Identifies the structure. */ 119 __u8 bar; /* Where to find it. */ 120 __u8 padding[3]; /* Pad to full dword. */ 121 __le32 offset; /* Offset within bar. */ 122 __le32 length; /* Length of the structure, in bytes. */ 123 }; 124 125 struct virtio_pci_notify_cap { 126 struct virtio_pci_cap cap; 127 __le32 notify_off_multiplier; /* Multiplier for queue_notify_off. */ 128 }; 129 130 /* Fields in VIRTIO_PCI_CAP_COMMON_CFG: */ 131 struct virtio_pci_common_cfg { 132 /* About the whole device. */ 133 __le32 device_feature_select; /* read-write */ 134 __le32 device_feature; /* read-only */ 135 __le32 guest_feature_select; /* read-write */ 136 __le32 guest_feature; /* read-write */ 137 __le16 msix_config; /* read-write */ 138 __le16 num_queues; /* read-only */ 139 __u8 device_status; /* read-write */ 140 __u8 config_generation; /* read-only */ 141 142 /* About a specific virtqueue. */ 143 __le16 queue_select; /* read-write */ 144 __le16 queue_size; /* read-write, power of 2. */ 145 __le16 queue_msix_vector; /* read-write */ 146 __le16 queue_enable; /* read-write */ 147 __le16 queue_notify_off; /* read-only */ 148 __le32 queue_desc_lo; /* read-write */ 149 __le32 queue_desc_hi; /* read-write */ 150 __le32 queue_avail_lo; /* read-write */ 151 __le32 queue_avail_hi; /* read-write */ 152 __le32 queue_used_lo; /* read-write */ 153 __le32 queue_used_hi; /* read-write */ 154 }; 155 156 #define MAX_QUEUES_PER_DEVICE_DEFAULT 8 157 158 typedef struct virtio_queue_info 159 { 160 /* the actual virtqueue */ 161 struct virtqueue *vq; 162 /* the number of entries in the queue */ 163 u16 num; 164 /* the virtual address of the ring queue */ 165 void *queue; 166 } VirtIOQueueInfo; 167 168 typedef struct virtio_system_ops { 169 // device register access 170 u8 (*vdev_read_byte)(ULONG_PTR ulRegister); 171 u16 (*vdev_read_word)(ULONG_PTR ulRegister); 172 u32 (*vdev_read_dword)(ULONG_PTR ulRegister); 173 void (*vdev_write_byte)(ULONG_PTR ulRegister, u8 bValue); 174 void (*vdev_write_word)(ULONG_PTR ulRegister, u16 wValue); 175 void (*vdev_write_dword)(ULONG_PTR ulRegister, u32 ulValue); 176 177 // memory management 178 void *(*mem_alloc_contiguous_pages)(void *context, size_t size); 179 void (*mem_free_contiguous_pages)(void *context, void *virt); 180 ULONGLONG (*mem_get_physical_address)(void *context, void *virt); 181 void *(*mem_alloc_nonpaged_block)(void *context, size_t size); 182 void (*mem_free_nonpaged_block)(void *context, void *addr); 183 184 // PCI config space access 185 int (*pci_read_config_byte)(void *context, int where, u8 *bVal); 186 int (*pci_read_config_word)(void *context, int where, u16 *wVal); 187 int (*pci_read_config_dword)(void *context, int where, u32 *dwVal); 188 189 // PCI resource handling 190 size_t (*pci_get_resource_len)(void *context, int bar); 191 void *(*pci_map_address_range)(void *context, int bar, size_t offset, size_t maxlen); 192 193 // misc 194 u16 (*vdev_get_msix_vector)(void *context, int queue); 195 void (*vdev_sleep)(void *context, unsigned int msecs); 196 } VirtIOSystemOps; 197 198 struct virtio_device; 199 typedef struct virtio_device VirtIODevice; 200 201 struct virtio_device_ops 202 { 203 // read/write device config and read config generation counter 204 void (*get_config)(VirtIODevice *vdev, unsigned offset, void *buf, unsigned len); 205 void (*set_config)(VirtIODevice *vdev, unsigned offset, const void *buf, unsigned len); 206 u32 (*get_config_generation)(VirtIODevice *vdev); 207 208 // read/write device status byte and reset the device 209 u8 (*get_status)(VirtIODevice *vdev); 210 void (*set_status)(VirtIODevice *vdev, u8 status); 211 void (*reset)(VirtIODevice *vdev); 212 213 // get/set device feature bits 214 u64 (*get_features)(VirtIODevice *vdev); 215 NTSTATUS (*set_features)(VirtIODevice *vdev, u64 features); 216 217 // set config/queue MSI interrupt vector, returns the new vector 218 u16 (*set_config_vector)(VirtIODevice *vdev, u16 vector); 219 u16 (*set_queue_vector)(struct virtqueue *vq, u16 vector); 220 221 // query virtual queue size and memory requirements 222 NTSTATUS (*query_queue_alloc)(VirtIODevice *vdev, 223 unsigned index, unsigned short *pNumEntries, 224 unsigned long *pRingSize, 225 unsigned long *pHeapSize); 226 227 // allocate and initialize a queue 228 NTSTATUS (*setup_queue)(struct virtqueue **queue, 229 VirtIODevice *vdev, VirtIOQueueInfo *info, 230 unsigned idx, u16 msix_vec); 231 232 // tear down and deallocate a queue 233 void (*delete_queue)(VirtIOQueueInfo *info); 234 }; 235 236 struct virtio_device 237 { 238 // the I/O port BAR of the PCI device (legacy virtio devices only) 239 ULONG_PTR addr; 240 241 // true if the device uses MSI interrupts 242 bool msix_used; 243 244 // true if the VIRTIO_RING_F_EVENT_IDX feature flag has been negotiated 245 bool event_suppression_enabled; 246 247 // true if the VIRTIO_F_RING_PACKED feature flag has been negotiated 248 bool packed_ring; 249 250 // internal device operations, implemented separately for legacy and modern 251 const struct virtio_device_ops *device; 252 253 // external callbacks implemented separately by different driver model drivers 254 const struct virtio_system_ops *system; 255 256 // opaque context value passed as first argument to virtio_system_ops callbacks 257 void *DeviceContext; 258 259 // the ISR status field, reading causes the device to de-assert an interrupt 260 volatile u8 *isr; 261 262 // modern virtio device capabilities and related state 263 volatile struct virtio_pci_common_cfg *common; 264 volatile unsigned char *config; 265 volatile unsigned char *notify_base; 266 int notify_map_cap; 267 u32 notify_offset_multiplier; 268 269 size_t config_len; 270 size_t notify_len; 271 272 // maximum number of virtqueues that fit in the memory block pointed to by info 273 ULONG maxQueues; 274 275 // points to inline_info if not more than MAX_QUEUES_PER_DEVICE_DEFAULT queues 276 // are used, or to an external allocation otherwise 277 VirtIOQueueInfo *info; 278 VirtIOQueueInfo inline_info[MAX_QUEUES_PER_DEVICE_DEFAULT]; 279 }; 280 281 /* Driver API: device init and shutdown 282 * DeviceContext is a driver defined opaque value which will be passed to driver 283 * supplied callbacks described in pSystemOps. pSystemOps must be non-NULL and all 284 * its fields must be non-NULL. msix_used is true if and only if the device is 285 * configured with MSI support. 286 */ 287 NTSTATUS virtio_device_initialize(VirtIODevice *vdev, 288 const VirtIOSystemOps *pSystemOps, 289 void *DeviceContext, 290 bool msix_used); 291 void virtio_device_shutdown(VirtIODevice *vdev); 292 293 /* Driver API: device status manipulation 294 * virtio_set_status should not be called by new drivers. Device status should only 295 * be getting its bits set with virtio_add_status and reset all back to 0 with 296 * virtio_device_reset. virtio_device_ready is a special version of virtio_add_status 297 * which adds the VIRTIO_CONFIG_S_DRIVER_OK status bit. 298 */ 299 u8 virtio_get_status(VirtIODevice *vdev); 300 void virtio_set_status(VirtIODevice *vdev, u8 status); 301 void virtio_add_status(VirtIODevice *vdev, u8 status); 302 303 void virtio_device_reset(VirtIODevice *vdev); 304 void virtio_device_ready(VirtIODevice *vdev); 305 306 /* Driver API: device feature bitmap manipulation 307 * Features passed to virtio_set_features should be a subset of features offered by 308 * the device as returned from virtio_get_features. virtio_set_features sets the 309 * VIRTIO_CONFIG_S_FEATURES_OK status bit if it is supported by the device. 310 */ 311 #define virtio_is_feature_enabled(FeaturesList, Feature) (!!((FeaturesList) & (1ULL << (Feature)))) 312 #define virtio_feature_enable(FeaturesList, Feature) ((FeaturesList) |= (1ULL << (Feature))) 313 #define virtio_feature_disable(FeaturesList, Feature) ((FeaturesList) &= ~(1ULL << (Feature))) 314 315 u64 virtio_get_features(VirtIODevice *dev); 316 NTSTATUS virtio_set_features(VirtIODevice *vdev, u64 features); 317 318 /* Driver API: device configuration access 319 * Both virtio_get_config and virtio_set_config support arbitrary values of the len 320 * parameter. Config items of length 1, 2, and 4 are read/written using one access, 321 * length 8 is broken down to two 4 bytes accesses, and any other length is read or 322 * written byte by byte. 323 */ 324 void virtio_get_config(VirtIODevice *vdev, unsigned offset, 325 void *buf, unsigned len); 326 void virtio_set_config(VirtIODevice *vdev, unsigned offset, 327 void *buf, unsigned len); 328 329 /* Driver API: virtqueue setup 330 * virtio_reserve_queue_memory makes VirtioLib reserve memory for its virtqueue 331 * bookkeeping. Drivers should call this function if they intend to set up queues 332 * one by one with virtio_find_queue. virtio_find_queues (plural) internally takes 333 * care of the reservation and virtio_reserve_queue_memory need not be called. 334 * Note that in addition to queue interrupt vectors, virtio_find_queues also sets 335 * up the device config vector as a convenience. 336 * Drivers should treat the returned struct virtqueue pointers as opaque handles. 337 */ 338 NTSTATUS virtio_query_queue_allocation(VirtIODevice *vdev, unsigned index, 339 unsigned short *pNumEntries, 340 unsigned long *pRingSize, 341 unsigned long *pHeapSize); 342 343 NTSTATUS virtio_reserve_queue_memory(VirtIODevice *vdev, unsigned nvqs); 344 345 NTSTATUS virtio_find_queue(VirtIODevice *vdev, unsigned index, 346 struct virtqueue **vq); 347 NTSTATUS virtio_find_queues(VirtIODevice *vdev, unsigned nvqs, 348 struct virtqueue *vqs[]); 349 350 /* Driver API: virtqueue shutdown 351 * The device must be reset and re-initialized to re-setup queues after they have 352 * been deleted. 353 */ 354 void virtio_delete_queue(struct virtqueue *vq); 355 void virtio_delete_queues(VirtIODevice *vdev); 356 357 /* Driver API: virtqueue query and manipulation 358 * virtio_get_queue_descriptor_size 359 * is useful in situations where the driver has to prepare for the memory allocation 360 * performed by virtio_reserve_queue_memory beforehand. 361 */ 362 363 u32 virtio_get_queue_size(struct virtqueue *vq); 364 unsigned long virtio_get_indirect_page_capacity(); 365 366 static ULONG FORCEINLINE virtio_get_queue_descriptor_size() 367 { 368 return sizeof(VirtIOQueueInfo); 369 } 370 371 /* Driver API: interrupt handling 372 * virtio_set_config_vector and virtio_set_queue_vector set the MSI vector used for 373 * device configuration interrupt and queue interrupt, respectively. The driver may 374 * choose to either return the vector from the vdev_get_msix_vector callback (called 375 * as part of queue setup) or call these functions later. Note that setting the vector 376 * may fail which is indicated by the return value of VIRTIO_MSI_NO_VECTOR. 377 * virtio_read_isr_status returns the value of the ISR status register, note that it 378 * is not idempotent, calling the function makes the device de-assert the interrupt. 379 */ 380 u16 virtio_set_config_vector(VirtIODevice *vdev, u16 vector); 381 u16 virtio_set_queue_vector(struct virtqueue *vq, u16 vector); 382 383 u8 virtio_read_isr_status(VirtIODevice *vdev); 384 385 /* Driver API: miscellaneous helpers 386 * virtio_get_bar_index returns the corresponding BAR index given its physical address. 387 * This tends to be useful to all drivers since Windows doesn't provide reliable BAR 388 * indices as part of resource enumeration. The function returns -1 on failure. 389 */ 390 int virtio_get_bar_index(PPCI_COMMON_HEADER pPCIHeader, PHYSICAL_ADDRESS BasePA); 391 392 #endif 393