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