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