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 * sizes: array of virtqueue sizes 59 * Returns 0 on success or error status 60 * @del_vqs: free virtqueues found by find_vqs(). 61 * @synchronize_cbs: synchronize with the virtqueue callbacks (optional) 62 * The function guarantees that all memory operations on the 63 * queue before it are visible to the vring_interrupt() that is 64 * called after it. 65 * vdev: the virtio_device 66 * @get_features: get the array of feature bits for this device. 67 * vdev: the virtio_device 68 * Returns the first 64 feature bits (all we currently need). 69 * @finalize_features: confirm what device features we'll be using. 70 * vdev: the virtio_device 71 * This sends the driver feature bits to the device: it can change 72 * the dev->feature bits if it wants. 73 * Note: despite the name this can be called any number of times. 74 * Returns 0 on success or error status 75 * @bus_name: return the bus name associated with the device (optional) 76 * vdev: the virtio_device 77 * This returns a pointer to the bus name a la pci_name from which 78 * the caller can then copy. 79 * @set_vq_affinity: set the affinity for a virtqueue (optional). 80 * @get_vq_affinity: get the affinity for a virtqueue (optional). 81 * @get_shm_region: get a shared memory region based on the index. 82 * @disable_vq_and_reset: reset a queue individually (optional). 83 * vq: the virtqueue 84 * Returns 0 on success or error status 85 * disable_vq_and_reset will guarantee that the callbacks are disabled and 86 * synchronized. 87 * Except for the callback, the caller should guarantee that the vring is 88 * not accessed by any functions of virtqueue. 89 * @enable_vq_after_reset: enable a reset queue 90 * vq: the virtqueue 91 * Returns 0 on success or error status 92 * If disable_vq_and_reset is set, then enable_vq_after_reset must also be 93 * set. 94 */ 95 typedef void vq_callback_t(struct virtqueue *); 96 struct virtio_config_ops { 97 void (*get)(struct virtio_device *vdev, unsigned offset, 98 void *buf, unsigned len); 99 void (*set)(struct virtio_device *vdev, unsigned offset, 100 const void *buf, unsigned len); 101 u32 (*generation)(struct virtio_device *vdev); 102 u8 (*get_status)(struct virtio_device *vdev); 103 void (*set_status)(struct virtio_device *vdev, u8 status); 104 void (*reset)(struct virtio_device *vdev); 105 int (*find_vqs)(struct virtio_device *, unsigned nvqs, 106 struct virtqueue *vqs[], vq_callback_t *callbacks[], 107 const char * const names[], 108 u32 sizes[], 109 const bool *ctx, 110 struct irq_affinity *desc); 111 void (*del_vqs)(struct virtio_device *); 112 void (*synchronize_cbs)(struct virtio_device *); 113 u64 (*get_features)(struct virtio_device *vdev); 114 int (*finalize_features)(struct virtio_device *vdev); 115 const char *(*bus_name)(struct virtio_device *vdev); 116 int (*set_vq_affinity)(struct virtqueue *vq, 117 const struct cpumask *cpu_mask); 118 const struct cpumask *(*get_vq_affinity)(struct virtio_device *vdev, 119 int index); 120 bool (*get_shm_region)(struct virtio_device *vdev, 121 struct virtio_shm_region *region, u8 id); 122 int (*disable_vq_and_reset)(struct virtqueue *vq); 123 int (*enable_vq_after_reset)(struct virtqueue *vq); 124 }; 125 126 /* If driver didn't advertise the feature, it will never appear. */ 127 void virtio_check_driver_offered_feature(const struct virtio_device *vdev, 128 unsigned int fbit); 129 130 /** 131 * __virtio_test_bit - helper to test feature bits. For use by transports. 132 * Devices should normally use virtio_has_feature, 133 * which includes more checks. 134 * @vdev: the device 135 * @fbit: the feature bit 136 */ 137 static inline bool __virtio_test_bit(const 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 return vdev->features & BIT_ULL(fbit); 147 } 148 149 /** 150 * __virtio_set_bit - helper to set feature bits. For use by transports. 151 * @vdev: the device 152 * @fbit: the feature bit 153 */ 154 static inline void __virtio_set_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_clear_bit - helper to clear feature bits. For use by transports. 168 * @vdev: the device 169 * @fbit: the feature bit 170 */ 171 static inline void __virtio_clear_bit(struct virtio_device *vdev, 172 unsigned int fbit) 173 { 174 /* Did you forget to fix assumptions on max features? */ 175 if (__builtin_constant_p(fbit)) 176 BUILD_BUG_ON(fbit >= 64); 177 else 178 BUG_ON(fbit >= 64); 179 180 vdev->features &= ~BIT_ULL(fbit); 181 } 182 183 /** 184 * virtio_has_feature - helper to determine if this device has this feature. 185 * @vdev: the device 186 * @fbit: the feature bit 187 */ 188 static inline bool virtio_has_feature(const struct virtio_device *vdev, 189 unsigned int fbit) 190 { 191 if (fbit < VIRTIO_TRANSPORT_F_START) 192 virtio_check_driver_offered_feature(vdev, fbit); 193 194 return __virtio_test_bit(vdev, fbit); 195 } 196 197 /** 198 * virtio_has_dma_quirk - determine whether this device has the DMA quirk 199 * @vdev: the device 200 */ 201 static inline bool virtio_has_dma_quirk(const struct virtio_device *vdev) 202 { 203 /* 204 * Note the reverse polarity of the quirk feature (compared to most 205 * other features), this is for compatibility with legacy systems. 206 */ 207 return !virtio_has_feature(vdev, VIRTIO_F_ACCESS_PLATFORM); 208 } 209 210 static inline 211 struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev, 212 vq_callback_t *c, const char *n) 213 { 214 vq_callback_t *callbacks[] = { c }; 215 const char *names[] = { n }; 216 struct virtqueue *vq; 217 int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names, NULL, 218 NULL, NULL); 219 if (err < 0) 220 return ERR_PTR(err); 221 return vq; 222 } 223 224 static inline 225 int virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs, 226 struct virtqueue *vqs[], vq_callback_t *callbacks[], 227 const char * const names[], 228 struct irq_affinity *desc) 229 { 230 return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, NULL, 231 NULL, desc); 232 } 233 234 static inline 235 int virtio_find_vqs_ctx(struct virtio_device *vdev, unsigned nvqs, 236 struct virtqueue *vqs[], vq_callback_t *callbacks[], 237 const char * const names[], const bool *ctx, 238 struct irq_affinity *desc) 239 { 240 return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, NULL, 241 ctx, desc); 242 } 243 244 static inline 245 int virtio_find_vqs_ctx_size(struct virtio_device *vdev, u32 nvqs, 246 struct virtqueue *vqs[], 247 vq_callback_t *callbacks[], 248 const char * const names[], 249 u32 sizes[], 250 const bool *ctx, struct irq_affinity *desc) 251 { 252 return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, sizes, 253 ctx, desc); 254 } 255 256 /** 257 * virtio_synchronize_cbs - synchronize with virtqueue callbacks 258 * @vdev: the device 259 */ 260 static inline 261 void virtio_synchronize_cbs(struct virtio_device *dev) 262 { 263 if (dev->config->synchronize_cbs) { 264 dev->config->synchronize_cbs(dev); 265 } else { 266 /* 267 * A best effort fallback to synchronize with 268 * interrupts, preemption and softirq disabled 269 * regions. See comment above synchronize_rcu(). 270 */ 271 synchronize_rcu(); 272 } 273 } 274 275 /** 276 * virtio_device_ready - enable vq use in probe function 277 * @vdev: the device 278 * 279 * Driver must call this to use vqs in the probe function. 280 * 281 * Note: vqs are enabled automatically after probe returns. 282 */ 283 static inline 284 void virtio_device_ready(struct virtio_device *dev) 285 { 286 unsigned status = dev->config->get_status(dev); 287 288 WARN_ON(status & VIRTIO_CONFIG_S_DRIVER_OK); 289 290 #ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION 291 /* 292 * The virtio_synchronize_cbs() makes sure vring_interrupt() 293 * will see the driver specific setup if it sees vq->broken 294 * as false (even if the notifications come before DRIVER_OK). 295 */ 296 virtio_synchronize_cbs(dev); 297 __virtio_unbreak_device(dev); 298 #endif 299 /* 300 * The transport should ensure the visibility of vq->broken 301 * before setting DRIVER_OK. See the comments for the transport 302 * specific set_status() method. 303 * 304 * A well behaved device will only notify a virtqueue after 305 * DRIVER_OK, this means the device should "see" the coherenct 306 * memory write that set vq->broken as false which is done by 307 * the driver when it sees DRIVER_OK, then the following 308 * driver's vring_interrupt() will see vq->broken as false so 309 * we won't lose any notification. 310 */ 311 dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK); 312 } 313 314 static inline 315 const char *virtio_bus_name(struct virtio_device *vdev) 316 { 317 if (!vdev->config->bus_name) 318 return "virtio"; 319 return vdev->config->bus_name(vdev); 320 } 321 322 /** 323 * virtqueue_set_affinity - setting affinity for a virtqueue 324 * @vq: the virtqueue 325 * @cpu: the cpu no. 326 * 327 * Pay attention the function are best-effort: the affinity hint may not be set 328 * due to config support, irq type and sharing. 329 * 330 */ 331 static inline 332 int virtqueue_set_affinity(struct virtqueue *vq, const struct cpumask *cpu_mask) 333 { 334 struct virtio_device *vdev = vq->vdev; 335 if (vdev->config->set_vq_affinity) 336 return vdev->config->set_vq_affinity(vq, cpu_mask); 337 return 0; 338 } 339 340 static inline 341 bool virtio_get_shm_region(struct virtio_device *vdev, 342 struct virtio_shm_region *region, u8 id) 343 { 344 if (!vdev->config->get_shm_region) 345 return false; 346 return vdev->config->get_shm_region(vdev, region, id); 347 } 348 349 static inline bool virtio_is_little_endian(struct virtio_device *vdev) 350 { 351 return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) || 352 virtio_legacy_is_little_endian(); 353 } 354 355 /* Memory accessors */ 356 static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val) 357 { 358 return __virtio16_to_cpu(virtio_is_little_endian(vdev), val); 359 } 360 361 static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val) 362 { 363 return __cpu_to_virtio16(virtio_is_little_endian(vdev), val); 364 } 365 366 static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val) 367 { 368 return __virtio32_to_cpu(virtio_is_little_endian(vdev), val); 369 } 370 371 static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val) 372 { 373 return __cpu_to_virtio32(virtio_is_little_endian(vdev), val); 374 } 375 376 static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val) 377 { 378 return __virtio64_to_cpu(virtio_is_little_endian(vdev), val); 379 } 380 381 static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val) 382 { 383 return __cpu_to_virtio64(virtio_is_little_endian(vdev), val); 384 } 385 386 #define virtio_to_cpu(vdev, x) \ 387 _Generic((x), \ 388 __u8: (x), \ 389 __virtio16: virtio16_to_cpu((vdev), (x)), \ 390 __virtio32: virtio32_to_cpu((vdev), (x)), \ 391 __virtio64: virtio64_to_cpu((vdev), (x)) \ 392 ) 393 394 #define cpu_to_virtio(vdev, x, m) \ 395 _Generic((m), \ 396 __u8: (x), \ 397 __virtio16: cpu_to_virtio16((vdev), (x)), \ 398 __virtio32: cpu_to_virtio32((vdev), (x)), \ 399 __virtio64: cpu_to_virtio64((vdev), (x)) \ 400 ) 401 402 #define __virtio_native_type(structname, member) \ 403 typeof(virtio_to_cpu(NULL, ((structname*)0)->member)) 404 405 /* Config space accessors. */ 406 #define virtio_cread(vdev, structname, member, ptr) \ 407 do { \ 408 typeof(((structname*)0)->member) virtio_cread_v; \ 409 \ 410 might_sleep(); \ 411 /* Sanity check: must match the member's type */ \ 412 typecheck(typeof(virtio_to_cpu((vdev), virtio_cread_v)), *(ptr)); \ 413 \ 414 switch (sizeof(virtio_cread_v)) { \ 415 case 1: \ 416 case 2: \ 417 case 4: \ 418 vdev->config->get((vdev), \ 419 offsetof(structname, member), \ 420 &virtio_cread_v, \ 421 sizeof(virtio_cread_v)); \ 422 break; \ 423 default: \ 424 __virtio_cread_many((vdev), \ 425 offsetof(structname, member), \ 426 &virtio_cread_v, \ 427 1, \ 428 sizeof(virtio_cread_v)); \ 429 break; \ 430 } \ 431 *(ptr) = virtio_to_cpu(vdev, virtio_cread_v); \ 432 } while(0) 433 434 /* Config space accessors. */ 435 #define virtio_cwrite(vdev, structname, member, ptr) \ 436 do { \ 437 typeof(((structname*)0)->member) virtio_cwrite_v = \ 438 cpu_to_virtio(vdev, *(ptr), ((structname*)0)->member); \ 439 \ 440 might_sleep(); \ 441 /* Sanity check: must match the member's type */ \ 442 typecheck(typeof(virtio_to_cpu((vdev), virtio_cwrite_v)), *(ptr)); \ 443 \ 444 vdev->config->set((vdev), offsetof(structname, member), \ 445 &virtio_cwrite_v, \ 446 sizeof(virtio_cwrite_v)); \ 447 } while(0) 448 449 /* 450 * Nothing virtio-specific about these, but let's worry about generalizing 451 * these later. 452 */ 453 #define virtio_le_to_cpu(x) \ 454 _Generic((x), \ 455 __u8: (u8)(x), \ 456 __le16: (u16)le16_to_cpu(x), \ 457 __le32: (u32)le32_to_cpu(x), \ 458 __le64: (u64)le64_to_cpu(x) \ 459 ) 460 461 #define virtio_cpu_to_le(x, m) \ 462 _Generic((m), \ 463 __u8: (x), \ 464 __le16: cpu_to_le16(x), \ 465 __le32: cpu_to_le32(x), \ 466 __le64: cpu_to_le64(x) \ 467 ) 468 469 /* LE (e.g. modern) Config space accessors. */ 470 #define virtio_cread_le(vdev, structname, member, ptr) \ 471 do { \ 472 typeof(((structname*)0)->member) virtio_cread_v; \ 473 \ 474 might_sleep(); \ 475 /* Sanity check: must match the member's type */ \ 476 typecheck(typeof(virtio_le_to_cpu(virtio_cread_v)), *(ptr)); \ 477 \ 478 switch (sizeof(virtio_cread_v)) { \ 479 case 1: \ 480 case 2: \ 481 case 4: \ 482 vdev->config->get((vdev), \ 483 offsetof(structname, member), \ 484 &virtio_cread_v, \ 485 sizeof(virtio_cread_v)); \ 486 break; \ 487 default: \ 488 __virtio_cread_many((vdev), \ 489 offsetof(structname, member), \ 490 &virtio_cread_v, \ 491 1, \ 492 sizeof(virtio_cread_v)); \ 493 break; \ 494 } \ 495 *(ptr) = virtio_le_to_cpu(virtio_cread_v); \ 496 } while(0) 497 498 #define virtio_cwrite_le(vdev, structname, member, ptr) \ 499 do { \ 500 typeof(((structname*)0)->member) virtio_cwrite_v = \ 501 virtio_cpu_to_le(*(ptr), ((structname*)0)->member); \ 502 \ 503 might_sleep(); \ 504 /* Sanity check: must match the member's type */ \ 505 typecheck(typeof(virtio_le_to_cpu(virtio_cwrite_v)), *(ptr)); \ 506 \ 507 vdev->config->set((vdev), offsetof(structname, member), \ 508 &virtio_cwrite_v, \ 509 sizeof(virtio_cwrite_v)); \ 510 } while(0) 511 512 513 /* Read @count fields, @bytes each. */ 514 static inline void __virtio_cread_many(struct virtio_device *vdev, 515 unsigned int offset, 516 void *buf, size_t count, size_t bytes) 517 { 518 u32 old, gen = vdev->config->generation ? 519 vdev->config->generation(vdev) : 0; 520 int i; 521 522 might_sleep(); 523 do { 524 old = gen; 525 526 for (i = 0; i < count; i++) 527 vdev->config->get(vdev, offset + bytes * i, 528 buf + i * bytes, bytes); 529 530 gen = vdev->config->generation ? 531 vdev->config->generation(vdev) : 0; 532 } while (gen != old); 533 } 534 535 static inline void virtio_cread_bytes(struct virtio_device *vdev, 536 unsigned int offset, 537 void *buf, size_t len) 538 { 539 __virtio_cread_many(vdev, offset, buf, len, 1); 540 } 541 542 static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset) 543 { 544 u8 ret; 545 546 might_sleep(); 547 vdev->config->get(vdev, offset, &ret, sizeof(ret)); 548 return ret; 549 } 550 551 static inline void virtio_cwrite8(struct virtio_device *vdev, 552 unsigned int offset, u8 val) 553 { 554 might_sleep(); 555 vdev->config->set(vdev, offset, &val, sizeof(val)); 556 } 557 558 static inline u16 virtio_cread16(struct virtio_device *vdev, 559 unsigned int offset) 560 { 561 __virtio16 ret; 562 563 might_sleep(); 564 vdev->config->get(vdev, offset, &ret, sizeof(ret)); 565 return virtio16_to_cpu(vdev, ret); 566 } 567 568 static inline void virtio_cwrite16(struct virtio_device *vdev, 569 unsigned int offset, u16 val) 570 { 571 __virtio16 v; 572 573 might_sleep(); 574 v = cpu_to_virtio16(vdev, val); 575 vdev->config->set(vdev, offset, &v, sizeof(v)); 576 } 577 578 static inline u32 virtio_cread32(struct virtio_device *vdev, 579 unsigned int offset) 580 { 581 __virtio32 ret; 582 583 might_sleep(); 584 vdev->config->get(vdev, offset, &ret, sizeof(ret)); 585 return virtio32_to_cpu(vdev, ret); 586 } 587 588 static inline void virtio_cwrite32(struct virtio_device *vdev, 589 unsigned int offset, u32 val) 590 { 591 __virtio32 v; 592 593 might_sleep(); 594 v = cpu_to_virtio32(vdev, val); 595 vdev->config->set(vdev, offset, &v, sizeof(v)); 596 } 597 598 static inline u64 virtio_cread64(struct virtio_device *vdev, 599 unsigned int offset) 600 { 601 __virtio64 ret; 602 603 __virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret)); 604 return virtio64_to_cpu(vdev, ret); 605 } 606 607 static inline void virtio_cwrite64(struct virtio_device *vdev, 608 unsigned int offset, u64 val) 609 { 610 __virtio64 v; 611 612 might_sleep(); 613 v = cpu_to_virtio64(vdev, val); 614 vdev->config->set(vdev, offset, &v, sizeof(v)); 615 } 616 617 /* Conditional config space accessors. */ 618 #define virtio_cread_feature(vdev, fbit, structname, member, ptr) \ 619 ({ \ 620 int _r = 0; \ 621 if (!virtio_has_feature(vdev, fbit)) \ 622 _r = -ENOENT; \ 623 else \ 624 virtio_cread((vdev), structname, member, ptr); \ 625 _r; \ 626 }) 627 628 /* Conditional config space accessors. */ 629 #define virtio_cread_le_feature(vdev, fbit, structname, member, ptr) \ 630 ({ \ 631 int _r = 0; \ 632 if (!virtio_has_feature(vdev, fbit)) \ 633 _r = -ENOENT; \ 634 else \ 635 virtio_cread_le((vdev), structname, member, ptr); \ 636 _r; \ 637 }) 638 639 #endif /* _LINUX_VIRTIO_CONFIG_H */ 640