1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_VIRTIO_CONFIG_H 3 #define _LINUX_VIRTIO_CONFIG_H 4 5 #include <linux/err.h> 6 #include <linux/bug.h> 7 #include <linux/virtio.h> 8 #include <linux/virtio_byteorder.h> 9 #include <linux/compiler_types.h> 10 #include <uapi/linux/virtio_config.h> 11 12 struct irq_affinity; 13 14 struct virtio_shm_region { 15 u64 addr; 16 u64 len; 17 }; 18 19 typedef void vq_callback_t(struct virtqueue *); 20 21 /** 22 * struct virtqueue_info - Info for a virtqueue passed to find_vqs(). 23 * @name: virtqueue description. Used mainly for debugging, NULL for 24 * a virtqueue unused by the driver. 25 * @callback: A callback to invoke on a used buffer notification. 26 * NULL for a virtqueue that does not need a callback. 27 * @ctx: A flag to indicate to maintain an extra context per virtqueue. 28 */ 29 struct virtqueue_info { 30 const char *name; 31 vq_callback_t *callback; 32 bool ctx; 33 }; 34 35 /** 36 * struct virtio_config_ops - operations for configuring a virtio device 37 * Note: Do not assume that a transport implements all of the operations 38 * getting/setting a value as a simple read/write! Generally speaking, 39 * any of @get/@set, @get_status/@set_status, or @get_features/ 40 * @finalize_features are NOT safe to be called from an atomic 41 * context. 42 * @get: read the value of a configuration field 43 * vdev: the virtio_device 44 * offset: the offset of the configuration field 45 * buf: the buffer to write the field value into. 46 * len: the length of the buffer 47 * @set: write the value of a configuration field 48 * vdev: the virtio_device 49 * offset: the offset of the configuration field 50 * buf: the buffer to read the field value from. 51 * len: the length of the buffer 52 * @generation: config generation counter (optional) 53 * vdev: the virtio_device 54 * Returns the config generation counter 55 * @get_status: read the status byte 56 * vdev: the virtio_device 57 * Returns the status byte 58 * @set_status: write the status byte 59 * vdev: the virtio_device 60 * status: the new status byte 61 * @reset: reset the device 62 * vdev: the virtio device 63 * After this, status and feature negotiation must be done again 64 * Device must not be reset from its vq/config callbacks, or in 65 * parallel with being added/removed. 66 * @find_vqs: find virtqueues and instantiate them. 67 * vdev: the virtio_device 68 * nvqs: the number of virtqueues to find 69 * vqs: on success, includes new virtqueues 70 * vqs_info: array of virtqueue info structures 71 * Returns 0 on success or error status 72 * @del_vqs: free virtqueues found by find_vqs(). 73 * @synchronize_cbs: synchronize with the virtqueue callbacks (optional) 74 * The function guarantees that all memory operations on the 75 * queue before it are visible to the vring_interrupt() that is 76 * called after it. 77 * vdev: the virtio_device 78 * @get_features: get the array of feature bits for this device. 79 * vdev: the virtio_device 80 * Returns the first 64 feature bits. 81 * @get_extended_features: 82 * vdev: the virtio_device 83 * Returns the first VIRTIO_FEATURES_MAX feature bits (all we currently 84 * need). 85 * @finalize_features: confirm what device features we'll be using. 86 * vdev: the virtio_device 87 * This sends the driver feature bits to the device: it can change 88 * the dev->feature bits if it wants. 89 * Note that despite the name this can be called any number of 90 * times. 91 * Returns 0 on success or error status 92 * @bus_name: return the bus name associated with the device (optional) 93 * vdev: the virtio_device 94 * This returns a pointer to the bus name a la pci_name from which 95 * the caller can then copy. 96 * @set_vq_affinity: set the affinity for a virtqueue (optional). 97 * @get_vq_affinity: get the affinity for a virtqueue (optional). 98 * @get_shm_region: get a shared memory region based on the index. 99 * @disable_vq_and_reset: reset a queue individually (optional). 100 * vq: the virtqueue 101 * Returns 0 on success or error status 102 * disable_vq_and_reset will guarantee that the callbacks are disabled and 103 * synchronized. 104 * Except for the callback, the caller should guarantee that the vring is 105 * not accessed by any functions of virtqueue. 106 * @enable_vq_after_reset: enable a reset queue 107 * vq: the virtqueue 108 * Returns 0 on success or error status 109 * If disable_vq_and_reset is set, then enable_vq_after_reset must also be 110 * set. 111 */ 112 struct virtio_config_ops { 113 void (*get)(struct virtio_device *vdev, unsigned offset, 114 void *buf, unsigned len); 115 void (*set)(struct virtio_device *vdev, unsigned offset, 116 const void *buf, unsigned len); 117 u32 (*generation)(struct virtio_device *vdev); 118 u8 (*get_status)(struct virtio_device *vdev); 119 void (*set_status)(struct virtio_device *vdev, u8 status); 120 void (*reset)(struct virtio_device *vdev); 121 int (*find_vqs)(struct virtio_device *vdev, unsigned int nvqs, 122 struct virtqueue *vqs[], 123 struct virtqueue_info vqs_info[], 124 struct irq_affinity *desc); 125 void (*del_vqs)(struct virtio_device *); 126 void (*synchronize_cbs)(struct virtio_device *); 127 u64 (*get_features)(struct virtio_device *vdev); 128 void (*get_extended_features)(struct virtio_device *vdev, 129 u64 *features); 130 int (*finalize_features)(struct virtio_device *vdev); 131 const char *(*bus_name)(struct virtio_device *vdev); 132 int (*set_vq_affinity)(struct virtqueue *vq, 133 const struct cpumask *cpu_mask); 134 const struct cpumask *(*get_vq_affinity)(struct virtio_device *vdev, 135 int index); 136 bool (*get_shm_region)(struct virtio_device *vdev, 137 struct virtio_shm_region *region, u8 id); 138 int (*disable_vq_and_reset)(struct virtqueue *vq); 139 int (*enable_vq_after_reset)(struct virtqueue *vq); 140 }; 141 142 /** 143 * struct virtio_map_ops - operations for mapping buffer for a virtio device 144 * Note: For transport that has its own mapping logic it must 145 * implements all of the operations 146 * @map_page: map a buffer to the device 147 * map: metadata for performing mapping 148 * page: the page that will be mapped by the device 149 * offset: the offset in the page for a buffer 150 * size: the buffer size 151 * dir: mapping direction 152 * attrs: mapping attributes 153 * Returns: the mapped address 154 * @unmap_page: unmap a buffer from the device 155 * map: device specific mapping map 156 * map_handle: the mapped address 157 * size: the buffer size 158 * dir: mapping direction 159 * attrs: unmapping attributes 160 * @sync_single_for_cpu: sync a single buffer from device to cpu 161 * map: metadata for performing mapping 162 * map_handle: the mapping address to sync 163 * size: the size of the buffer 164 * dir: synchronization direction 165 * @sync_single_for_device: sync a single buffer from cpu to device 166 * map: metadata for performing mapping 167 * map_handle: the mapping address to sync 168 * size: the size of the buffer 169 * dir: synchronization direction 170 * @alloc: alloc a coherent buffer mapping 171 * map: metadata for performing mapping 172 * size: the size of the buffer 173 * map_handle: the mapping address to sync 174 * gfp: allocation flag (GFP_XXX) 175 * Returns: virtual address of the allocated buffer 176 * @free: free a coherent buffer mapping 177 * map: metadata for performing mapping 178 * size: the size of the buffer 179 * vaddr: virtual address of the buffer 180 * map_handle: the mapping address to sync 181 * attrs: unmapping attributes 182 * @need_sync: if the buffer needs synchronization 183 * map: metadata for performing mapping 184 * map_handle: the mapped address 185 * Returns: whether the buffer needs synchronization 186 * @mapping_error: if the mapping address is error 187 * map: metadata for performing mapping 188 * map_handle: the mapped address 189 * @max_mapping_size: get the maximum buffer size that can be mapped 190 * map: metadata for performing mapping 191 * Returns: the maximum buffer size that can be mapped 192 */ 193 struct virtio_map_ops { 194 dma_addr_t (*map_page)(union virtio_map map, struct page *page, 195 unsigned long offset, size_t size, 196 enum dma_data_direction dir, unsigned long attrs); 197 void (*unmap_page)(union virtio_map map, dma_addr_t map_handle, 198 size_t size, enum dma_data_direction dir, 199 unsigned long attrs); 200 void (*sync_single_for_cpu)(union virtio_map map, dma_addr_t map_handle, 201 size_t size, enum dma_data_direction dir); 202 void (*sync_single_for_device)(union virtio_map map, 203 dma_addr_t map_handle, size_t size, 204 enum dma_data_direction dir); 205 void *(*alloc)(union virtio_map map, size_t size, 206 dma_addr_t *map_handle, gfp_t gfp); 207 void (*free)(union virtio_map map, size_t size, void *vaddr, 208 dma_addr_t map_handle, unsigned long attrs); 209 bool (*need_sync)(union virtio_map map, dma_addr_t map_handle); 210 int (*mapping_error)(union virtio_map map, dma_addr_t map_handle); 211 size_t (*max_mapping_size)(union virtio_map map); 212 }; 213 214 /* If driver didn't advertise the feature, it will never appear. */ 215 void virtio_check_driver_offered_feature(const struct virtio_device *vdev, 216 unsigned int fbit); 217 218 /** 219 * __virtio_test_bit - helper to test feature bits. For use by transports. 220 * Devices should normally use virtio_has_feature, 221 * which includes more checks. 222 * @vdev: the device 223 * @fbit: the feature bit 224 */ 225 static inline bool __virtio_test_bit(const struct virtio_device *vdev, 226 unsigned int fbit) 227 { 228 return virtio_features_test_bit(vdev->features_array, fbit); 229 } 230 231 /** 232 * __virtio_set_bit - helper to set feature bits. For use by transports. 233 * @vdev: the device 234 * @fbit: the feature bit 235 */ 236 static inline void __virtio_set_bit(struct virtio_device *vdev, 237 unsigned int fbit) 238 { 239 virtio_features_set_bit(vdev->features_array, fbit); 240 } 241 242 /** 243 * __virtio_clear_bit - helper to clear feature bits. For use by transports. 244 * @vdev: the device 245 * @fbit: the feature bit 246 */ 247 static inline void __virtio_clear_bit(struct virtio_device *vdev, 248 unsigned int fbit) 249 { 250 virtio_features_clear_bit(vdev->features_array, fbit); 251 } 252 253 /** 254 * virtio_has_feature - helper to determine if this device has this feature. 255 * @vdev: the device 256 * @fbit: the feature bit 257 */ 258 static inline bool virtio_has_feature(const struct virtio_device *vdev, 259 unsigned int fbit) 260 { 261 if (fbit < VIRTIO_TRANSPORT_F_START) 262 virtio_check_driver_offered_feature(vdev, fbit); 263 264 return __virtio_test_bit(vdev, fbit); 265 } 266 267 static inline void virtio_get_features(struct virtio_device *vdev, 268 u64 *features_out) 269 { 270 if (vdev->config->get_extended_features) { 271 vdev->config->get_extended_features(vdev, features_out); 272 return; 273 } 274 275 virtio_features_from_u64(features_out, 276 vdev->config->get_features(vdev)); 277 } 278 279 /** 280 * virtio_has_dma_quirk - determine whether this device has the DMA quirk 281 * @vdev: the device 282 */ 283 static inline bool virtio_has_dma_quirk(const struct virtio_device *vdev) 284 { 285 /* 286 * Note the reverse polarity of the quirk feature (compared to most 287 * other features), this is for compatibility with legacy systems. 288 */ 289 return !virtio_has_feature(vdev, VIRTIO_F_ACCESS_PLATFORM); 290 } 291 292 static inline 293 int virtio_find_vqs(struct virtio_device *vdev, unsigned int nvqs, 294 struct virtqueue *vqs[], 295 struct virtqueue_info vqs_info[], 296 struct irq_affinity *desc) 297 { 298 return vdev->config->find_vqs(vdev, nvqs, vqs, vqs_info, desc); 299 } 300 301 static inline 302 struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev, 303 vq_callback_t *c, const char *n) 304 { 305 struct virtqueue_info vqs_info[] = { 306 { n, c }, 307 }; 308 struct virtqueue *vq; 309 int err = virtio_find_vqs(vdev, 1, &vq, vqs_info, NULL); 310 311 if (err < 0) 312 return ERR_PTR(err); 313 return vq; 314 } 315 316 /** 317 * virtio_synchronize_cbs - synchronize with virtqueue callbacks 318 * @dev: the virtio device 319 */ 320 static inline 321 void virtio_synchronize_cbs(struct virtio_device *dev) 322 { 323 if (dev->config->synchronize_cbs) { 324 dev->config->synchronize_cbs(dev); 325 } else { 326 /* 327 * A best effort fallback to synchronize with 328 * interrupts, preemption and softirq disabled 329 * regions. See comment above synchronize_rcu(). 330 */ 331 synchronize_rcu(); 332 } 333 } 334 335 /** 336 * virtio_device_ready - enable vq use in probe function 337 * @dev: the virtio device 338 * 339 * Driver must call this to use vqs in the probe function. 340 * 341 * Note: vqs are enabled automatically after probe returns. 342 */ 343 static inline 344 void virtio_device_ready(struct virtio_device *dev) 345 { 346 unsigned status = dev->config->get_status(dev); 347 348 WARN_ON(status & VIRTIO_CONFIG_S_DRIVER_OK); 349 350 #ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION 351 /* 352 * The virtio_synchronize_cbs() makes sure vring_interrupt() 353 * will see the driver specific setup if it sees vq->broken 354 * as false (even if the notifications come before DRIVER_OK). 355 */ 356 virtio_synchronize_cbs(dev); 357 __virtio_unbreak_device(dev); 358 #endif 359 /* 360 * The transport should ensure the visibility of vq->broken 361 * before setting DRIVER_OK. See the comments for the transport 362 * specific set_status() method. 363 * 364 * A well behaved device will only notify a virtqueue after 365 * DRIVER_OK, this means the device should "see" the coherenct 366 * memory write that set vq->broken as false which is done by 367 * the driver when it sees DRIVER_OK, then the following 368 * driver's vring_interrupt() will see vq->broken as false so 369 * we won't lose any notification. 370 */ 371 dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK); 372 } 373 374 static inline 375 const char *virtio_bus_name(struct virtio_device *vdev) 376 { 377 if (!vdev->config->bus_name) 378 return "virtio"; 379 return vdev->config->bus_name(vdev); 380 } 381 382 /** 383 * virtqueue_set_affinity - setting affinity for a virtqueue 384 * @vq: the virtqueue 385 * @cpu_mask: the cpu mask 386 * 387 * Pay attention the function are best-effort: the affinity hint may not be set 388 * due to config support, irq type and sharing. 389 * 390 */ 391 static inline 392 int virtqueue_set_affinity(struct virtqueue *vq, const struct cpumask *cpu_mask) 393 { 394 struct virtio_device *vdev = vq->vdev; 395 if (vdev->config->set_vq_affinity) 396 return vdev->config->set_vq_affinity(vq, cpu_mask); 397 return 0; 398 } 399 400 static inline 401 bool virtio_get_shm_region(struct virtio_device *vdev, 402 struct virtio_shm_region *region_out, u8 id) 403 { 404 if (!vdev->config->get_shm_region) 405 return false; 406 return vdev->config->get_shm_region(vdev, region_out, id); 407 } 408 409 static inline bool virtio_is_little_endian(struct virtio_device *vdev) 410 { 411 return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) || 412 virtio_legacy_is_little_endian(); 413 } 414 415 /* Memory accessors */ 416 static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val) 417 { 418 return __virtio16_to_cpu(virtio_is_little_endian(vdev), val); 419 } 420 421 static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val) 422 { 423 return __cpu_to_virtio16(virtio_is_little_endian(vdev), val); 424 } 425 426 static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val) 427 { 428 return __virtio32_to_cpu(virtio_is_little_endian(vdev), val); 429 } 430 431 static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val) 432 { 433 return __cpu_to_virtio32(virtio_is_little_endian(vdev), val); 434 } 435 436 static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val) 437 { 438 return __virtio64_to_cpu(virtio_is_little_endian(vdev), val); 439 } 440 441 static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val) 442 { 443 return __cpu_to_virtio64(virtio_is_little_endian(vdev), val); 444 } 445 446 #define virtio_to_cpu(vdev, x) \ 447 _Generic((x), \ 448 __u8: (x), \ 449 __virtio16: virtio16_to_cpu((vdev), (x)), \ 450 __virtio32: virtio32_to_cpu((vdev), (x)), \ 451 __virtio64: virtio64_to_cpu((vdev), (x)) \ 452 ) 453 454 #define cpu_to_virtio(vdev, x, m) \ 455 _Generic((m), \ 456 __u8: (x), \ 457 __virtio16: cpu_to_virtio16((vdev), (x)), \ 458 __virtio32: cpu_to_virtio32((vdev), (x)), \ 459 __virtio64: cpu_to_virtio64((vdev), (x)) \ 460 ) 461 462 #define __virtio_native_type(structname, member) \ 463 typeof(virtio_to_cpu(NULL, ((structname*)0)->member)) 464 465 /* Config space accessors. */ 466 #define virtio_cread(vdev, structname, member, ptr) \ 467 do { \ 468 typeof(((structname*)0)->member) virtio_cread_v; \ 469 \ 470 might_sleep(); \ 471 /* Sanity check: must match the member's type */ \ 472 typecheck(typeof(virtio_to_cpu((vdev), virtio_cread_v)), *(ptr)); \ 473 \ 474 switch (sizeof(virtio_cread_v)) { \ 475 case 1: \ 476 case 2: \ 477 case 4: \ 478 vdev->config->get((vdev), \ 479 offsetof(structname, member), \ 480 &virtio_cread_v, \ 481 sizeof(virtio_cread_v)); \ 482 break; \ 483 default: \ 484 __virtio_cread_many((vdev), \ 485 offsetof(structname, member), \ 486 &virtio_cread_v, \ 487 1, \ 488 sizeof(virtio_cread_v)); \ 489 break; \ 490 } \ 491 *(ptr) = virtio_to_cpu(vdev, virtio_cread_v); \ 492 } while(0) 493 494 /* Config space accessors. */ 495 #define virtio_cwrite(vdev, structname, member, ptr) \ 496 do { \ 497 typeof(((structname*)0)->member) virtio_cwrite_v = \ 498 cpu_to_virtio(vdev, *(ptr), ((structname*)0)->member); \ 499 \ 500 might_sleep(); \ 501 /* Sanity check: must match the member's type */ \ 502 typecheck(typeof(virtio_to_cpu((vdev), virtio_cwrite_v)), *(ptr)); \ 503 \ 504 vdev->config->set((vdev), offsetof(structname, member), \ 505 &virtio_cwrite_v, \ 506 sizeof(virtio_cwrite_v)); \ 507 } while(0) 508 509 /* 510 * Nothing virtio-specific about these, but let's worry about generalizing 511 * these later. 512 */ 513 #define virtio_le_to_cpu(x) \ 514 _Generic((x), \ 515 __u8: (u8)(x), \ 516 __le16: (u16)le16_to_cpu(x), \ 517 __le32: (u32)le32_to_cpu(x), \ 518 __le64: (u64)le64_to_cpu(x) \ 519 ) 520 521 #define virtio_cpu_to_le(x, m) \ 522 _Generic((m), \ 523 __u8: (x), \ 524 __le16: cpu_to_le16(x), \ 525 __le32: cpu_to_le32(x), \ 526 __le64: cpu_to_le64(x) \ 527 ) 528 529 /* LE (e.g. modern) Config space accessors. */ 530 #define virtio_cread_le(vdev, structname, member, ptr) \ 531 do { \ 532 typeof(((structname*)0)->member) virtio_cread_v; \ 533 \ 534 might_sleep(); \ 535 /* Sanity check: must match the member's type */ \ 536 typecheck(typeof(virtio_le_to_cpu(virtio_cread_v)), *(ptr)); \ 537 \ 538 switch (sizeof(virtio_cread_v)) { \ 539 case 1: \ 540 case 2: \ 541 case 4: \ 542 vdev->config->get((vdev), \ 543 offsetof(structname, member), \ 544 &virtio_cread_v, \ 545 sizeof(virtio_cread_v)); \ 546 break; \ 547 default: \ 548 __virtio_cread_many((vdev), \ 549 offsetof(structname, member), \ 550 &virtio_cread_v, \ 551 1, \ 552 sizeof(virtio_cread_v)); \ 553 break; \ 554 } \ 555 *(ptr) = virtio_le_to_cpu(virtio_cread_v); \ 556 } while(0) 557 558 #define virtio_cwrite_le(vdev, structname, member, ptr) \ 559 do { \ 560 typeof(((structname*)0)->member) virtio_cwrite_v = \ 561 virtio_cpu_to_le(*(ptr), ((structname*)0)->member); \ 562 \ 563 might_sleep(); \ 564 /* Sanity check: must match the member's type */ \ 565 typecheck(typeof(virtio_le_to_cpu(virtio_cwrite_v)), *(ptr)); \ 566 \ 567 vdev->config->set((vdev), offsetof(structname, member), \ 568 &virtio_cwrite_v, \ 569 sizeof(virtio_cwrite_v)); \ 570 } while(0) 571 572 573 /* Read @count fields, @bytes each. */ 574 static inline void __virtio_cread_many(struct virtio_device *vdev, 575 unsigned int offset, 576 void *buf, size_t count, size_t bytes) 577 { 578 u32 old, gen = vdev->config->generation ? 579 vdev->config->generation(vdev) : 0; 580 int i; 581 582 might_sleep(); 583 do { 584 old = gen; 585 586 for (i = 0; i < count; i++) 587 vdev->config->get(vdev, offset + bytes * i, 588 buf + i * bytes, bytes); 589 590 gen = vdev->config->generation ? 591 vdev->config->generation(vdev) : 0; 592 } while (gen != old); 593 } 594 595 static inline void virtio_cread_bytes(struct virtio_device *vdev, 596 unsigned int offset, 597 void *buf, size_t len) 598 { 599 __virtio_cread_many(vdev, offset, buf, len, 1); 600 } 601 602 static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset) 603 { 604 u8 ret; 605 606 might_sleep(); 607 vdev->config->get(vdev, offset, &ret, sizeof(ret)); 608 return ret; 609 } 610 611 static inline void virtio_cwrite8(struct virtio_device *vdev, 612 unsigned int offset, u8 val) 613 { 614 might_sleep(); 615 vdev->config->set(vdev, offset, &val, sizeof(val)); 616 } 617 618 static inline u16 virtio_cread16(struct virtio_device *vdev, 619 unsigned int offset) 620 { 621 __virtio16 ret; 622 623 might_sleep(); 624 vdev->config->get(vdev, offset, &ret, sizeof(ret)); 625 return virtio16_to_cpu(vdev, ret); 626 } 627 628 static inline void virtio_cwrite16(struct virtio_device *vdev, 629 unsigned int offset, u16 val) 630 { 631 __virtio16 v; 632 633 might_sleep(); 634 v = cpu_to_virtio16(vdev, val); 635 vdev->config->set(vdev, offset, &v, sizeof(v)); 636 } 637 638 static inline u32 virtio_cread32(struct virtio_device *vdev, 639 unsigned int offset) 640 { 641 __virtio32 ret; 642 643 might_sleep(); 644 vdev->config->get(vdev, offset, &ret, sizeof(ret)); 645 return virtio32_to_cpu(vdev, ret); 646 } 647 648 static inline void virtio_cwrite32(struct virtio_device *vdev, 649 unsigned int offset, u32 val) 650 { 651 __virtio32 v; 652 653 might_sleep(); 654 v = cpu_to_virtio32(vdev, val); 655 vdev->config->set(vdev, offset, &v, sizeof(v)); 656 } 657 658 static inline u64 virtio_cread64(struct virtio_device *vdev, 659 unsigned int offset) 660 { 661 __virtio64 ret; 662 663 __virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret)); 664 return virtio64_to_cpu(vdev, ret); 665 } 666 667 static inline void virtio_cwrite64(struct virtio_device *vdev, 668 unsigned int offset, u64 val) 669 { 670 __virtio64 v; 671 672 might_sleep(); 673 v = cpu_to_virtio64(vdev, val); 674 vdev->config->set(vdev, offset, &v, sizeof(v)); 675 } 676 677 /* Conditional config space accessors. */ 678 #define virtio_cread_feature(vdev, fbit, structname, member, ptr) \ 679 ({ \ 680 int _r = 0; \ 681 if (!virtio_has_feature(vdev, fbit)) \ 682 _r = -ENOENT; \ 683 else \ 684 virtio_cread((vdev), structname, member, ptr); \ 685 _r; \ 686 }) 687 688 /* Conditional config space accessors. */ 689 #define virtio_cread_le_feature(vdev, fbit, structname, member, ptr) \ 690 ({ \ 691 int _r = 0; \ 692 if (!virtio_has_feature(vdev, fbit)) \ 693 _r = -ENOENT; \ 694 else \ 695 virtio_cread_le((vdev), structname, member, ptr); \ 696 _r; \ 697 }) 698 699 #endif /* _LINUX_VIRTIO_CONFIG_H */ 700