1226048Sobrien/* SPDX-License-Identifier: GPL-2.0 */ 268349Sobrien#ifndef _LINUX_VIRTIO_CONFIG_H 3267843Sdelphij#define _LINUX_VIRTIO_CONFIG_H 4191736Sobrien 5226048Sobrien#include <linux/err.h> 6191736Sobrien#include <linux/bug.h> 7191736Sobrien#include <linux/virtio.h> 8226048Sobrien#include <linux/virtio_byteorder.h> 9226048Sobrien#include <linux/compiler_types.h> 10226048Sobrien#include <uapi/linux/virtio_config.h> 11226048Sobrien 12226048Sobrienstruct irq_affinity; 13226048Sobrien 14226048Sobrienstruct virtio_shm_region { 15226048Sobrien u64 addr; 1668349Sobrien u64 len; 17226048Sobrien}; 18226048Sobrien 19226048Sobrientypedef void vq_callback_t(struct virtqueue *); 20226048Sobrien 21226048Sobrien/** 22226048Sobrien * struct virtio_config_ops - operations for configuring a virtio device 23226048Sobrien * Note: Do not assume that a transport implements all of the operations 24267843Sdelphij * getting/setting a value as a simple read/write! Generally speaking, 25226048Sobrien * any of @get/@set, @get_status/@set_status, or @get_features/ 26226048Sobrien * @finalize_features are NOT safe to be called from an atomic 27226048Sobrien * context. 28226048Sobrien * @get: read the value of a configuration field 29226048Sobrien * vdev: the virtio_device 30226048Sobrien * offset: the offset of the configuration field 31226048Sobrien * buf: the buffer to write the field value into. 32226048Sobrien * len: the length of the buffer 33267843Sdelphij * @set: write the value of a configuration field 34267843Sdelphij * vdev: the virtio_device 35226048Sobrien * offset: the offset of the configuration field 36226048Sobrien * buf: the buffer to read the field value from. 37226048Sobrien * len: the length of the buffer 38226048Sobrien * @generation: config generation counter (optional) 39226048Sobrien * vdev: the virtio_device 40267843Sdelphij * Returns the config generation counter 41267843Sdelphij * @get_status: read the status byte 42267843Sdelphij * vdev: the virtio_device 43267843Sdelphij * Returns the status byte 44267843Sdelphij * @set_status: write the status byte 45267843Sdelphij * vdev: the virtio_device 46226048Sobrien * status: the new status byte 47226048Sobrien * @reset: reset the device 48226048Sobrien * vdev: the virtio device 49226048Sobrien * After this, status and feature negotiation must be done again 50226048Sobrien * Device must not be reset from its vq/config callbacks, or in 51226048Sobrien * parallel with being added/removed. 52226048Sobrien * @find_vqs: find virtqueues and instantiate them. 53226048Sobrien * vdev: the virtio_device 54226048Sobrien * nvqs: the number of virtqueues to find 55226048Sobrien * vqs: on success, includes new virtqueues 56226048Sobrien * callbacks: array of callbacks, for each virtqueue 57226048Sobrien * include a NULL entry for vqs that do not need a callback 58226048Sobrien * names: array of virtqueue names (mainly for debugging) 59226048Sobrien * include a NULL entry for vqs unused by driver 60226048Sobrien * Returns 0 on success or error status 61226048Sobrien * @del_vqs: free virtqueues found by find_vqs(). 62226048Sobrien * @synchronize_cbs: synchronize with the virtqueue callbacks (optional) 63 * The function guarantees that all memory operations on the 64 * queue before it are visible to the vring_interrupt() that is 65 * called after it. 66 * vdev: the virtio_device 67 * @get_features: get the array of feature bits for this device. 68 * vdev: the virtio_device 69 * Returns the first 64 feature bits (all we currently need). 70 * @finalize_features: confirm what device features we'll be using. 71 * vdev: the virtio_device 72 * This sends the driver feature bits to the device: it can change 73 * the dev->feature bits if it wants. 74 * Note that despite the name this can be called any number of 75 * times. 76 * Returns 0 on success or error status 77 * @bus_name: return the bus name associated with the device (optional) 78 * vdev: the virtio_device 79 * This returns a pointer to the bus name a la pci_name from which 80 * the caller can then copy. 81 * @set_vq_affinity: set the affinity for a virtqueue (optional). 82 * @get_vq_affinity: get the affinity for a virtqueue (optional). 83 * @get_shm_region: get a shared memory region based on the index. 84 * @disable_vq_and_reset: reset a queue individually (optional). 85 * vq: the virtqueue 86 * Returns 0 on success or error status 87 * disable_vq_and_reset will guarantee that the callbacks are disabled and 88 * synchronized. 89 * Except for the callback, the caller should guarantee that the vring is 90 * not accessed by any functions of virtqueue. 91 * @enable_vq_after_reset: enable a reset queue 92 * vq: the virtqueue 93 * Returns 0 on success or error status 94 * If disable_vq_and_reset is set, then enable_vq_after_reset must also be 95 * set. 96 * @create_avq: create admin virtqueue resource. 97 * @destroy_avq: destroy admin virtqueue resource. 98 */ 99struct virtio_config_ops { 100 void (*get)(struct virtio_device *vdev, unsigned offset, 101 void *buf, unsigned len); 102 void (*set)(struct virtio_device *vdev, unsigned offset, 103 const void *buf, unsigned len); 104 u32 (*generation)(struct virtio_device *vdev); 105 u8 (*get_status)(struct virtio_device *vdev); 106 void (*set_status)(struct virtio_device *vdev, u8 status); 107 void (*reset)(struct virtio_device *vdev); 108 int (*find_vqs)(struct virtio_device *, unsigned nvqs, 109 struct virtqueue *vqs[], vq_callback_t *callbacks[], 110 const char * const names[], const bool *ctx, 111 struct irq_affinity *desc); 112 void (*del_vqs)(struct virtio_device *); 113 void (*synchronize_cbs)(struct virtio_device *); 114 u64 (*get_features)(struct virtio_device *vdev); 115 int (*finalize_features)(struct virtio_device *vdev); 116 const char *(*bus_name)(struct virtio_device *vdev); 117 int (*set_vq_affinity)(struct virtqueue *vq, 118 const struct cpumask *cpu_mask); 119 const struct cpumask *(*get_vq_affinity)(struct virtio_device *vdev, 120 int index); 121 bool (*get_shm_region)(struct virtio_device *vdev, 122 struct virtio_shm_region *region, u8 id); 123 int (*disable_vq_and_reset)(struct virtqueue *vq); 124 int (*enable_vq_after_reset)(struct virtqueue *vq); 125 int (*create_avq)(struct virtio_device *vdev); 126 void (*destroy_avq)(struct virtio_device *vdev); 127}; 128 129/* If driver didn't advertise the feature, it will never appear. */ 130void virtio_check_driver_offered_feature(const struct virtio_device *vdev, 131 unsigned int fbit); 132 133/** 134 * __virtio_test_bit - helper to test feature bits. For use by transports. 135 * Devices should normally use virtio_has_feature, 136 * which includes more checks. 137 * @vdev: the device 138 * @fbit: the feature bit 139 */ 140static inline bool __virtio_test_bit(const struct virtio_device *vdev, 141 unsigned int fbit) 142{ 143 /* Did you forget to fix assumptions on max features? */ 144 if (__builtin_constant_p(fbit)) 145 BUILD_BUG_ON(fbit >= 64); 146 else 147 BUG_ON(fbit >= 64); 148 149 return vdev->features & BIT_ULL(fbit); 150} 151 152/** 153 * __virtio_set_bit - helper to set feature bits. For use by transports. 154 * @vdev: the device 155 * @fbit: the feature bit 156 */ 157static inline void __virtio_set_bit(struct virtio_device *vdev, 158 unsigned int fbit) 159{ 160 /* Did you forget to fix assumptions on max features? */ 161 if (__builtin_constant_p(fbit)) 162 BUILD_BUG_ON(fbit >= 64); 163 else 164 BUG_ON(fbit >= 64); 165 166 vdev->features |= BIT_ULL(fbit); 167} 168 169/** 170 * __virtio_clear_bit - helper to clear feature bits. For use by transports. 171 * @vdev: the device 172 * @fbit: the feature bit 173 */ 174static inline void __virtio_clear_bit(struct virtio_device *vdev, 175 unsigned int fbit) 176{ 177 /* Did you forget to fix assumptions on max features? */ 178 if (__builtin_constant_p(fbit)) 179 BUILD_BUG_ON(fbit >= 64); 180 else 181 BUG_ON(fbit >= 64); 182 183 vdev->features &= ~BIT_ULL(fbit); 184} 185 186/** 187 * virtio_has_feature - helper to determine if this device has this feature. 188 * @vdev: the device 189 * @fbit: the feature bit 190 */ 191static inline bool virtio_has_feature(const struct virtio_device *vdev, 192 unsigned int fbit) 193{ 194 if (fbit < VIRTIO_TRANSPORT_F_START) 195 virtio_check_driver_offered_feature(vdev, fbit); 196 197 return __virtio_test_bit(vdev, fbit); 198} 199 200/** 201 * virtio_has_dma_quirk - determine whether this device has the DMA quirk 202 * @vdev: the device 203 */ 204static inline bool virtio_has_dma_quirk(const struct virtio_device *vdev) 205{ 206 /* 207 * Note the reverse polarity of the quirk feature (compared to most 208 * other features), this is for compatibility with legacy systems. 209 */ 210 return !virtio_has_feature(vdev, VIRTIO_F_ACCESS_PLATFORM); 211} 212 213static inline 214struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev, 215 vq_callback_t *c, const char *n) 216{ 217 vq_callback_t *callbacks[] = { c }; 218 const char *names[] = { n }; 219 struct virtqueue *vq; 220 int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names, NULL, 221 NULL); 222 if (err < 0) 223 return ERR_PTR(err); 224 return vq; 225} 226 227static inline 228int virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs, 229 struct virtqueue *vqs[], vq_callback_t *callbacks[], 230 const char * const names[], 231 struct irq_affinity *desc) 232{ 233 return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, NULL, desc); 234} 235 236static inline 237int virtio_find_vqs_ctx(struct virtio_device *vdev, unsigned nvqs, 238 struct virtqueue *vqs[], vq_callback_t *callbacks[], 239 const char * const names[], const bool *ctx, 240 struct irq_affinity *desc) 241{ 242 return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, ctx, 243 desc); 244} 245 246/** 247 * virtio_synchronize_cbs - synchronize with virtqueue callbacks 248 * @dev: the virtio device 249 */ 250static inline 251void virtio_synchronize_cbs(struct virtio_device *dev) 252{ 253 if (dev->config->synchronize_cbs) { 254 dev->config->synchronize_cbs(dev); 255 } else { 256 /* 257 * A best effort fallback to synchronize with 258 * interrupts, preemption and softirq disabled 259 * regions. See comment above synchronize_rcu(). 260 */ 261 synchronize_rcu(); 262 } 263} 264 265/** 266 * virtio_device_ready - enable vq use in probe function 267 * @dev: the virtio device 268 * 269 * Driver must call this to use vqs in the probe function. 270 * 271 * Note: vqs are enabled automatically after probe returns. 272 */ 273static inline 274void virtio_device_ready(struct virtio_device *dev) 275{ 276 unsigned status = dev->config->get_status(dev); 277 278 WARN_ON(status & VIRTIO_CONFIG_S_DRIVER_OK); 279 280#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION 281 /* 282 * The virtio_synchronize_cbs() makes sure vring_interrupt() 283 * will see the driver specific setup if it sees vq->broken 284 * as false (even if the notifications come before DRIVER_OK). 285 */ 286 virtio_synchronize_cbs(dev); 287 __virtio_unbreak_device(dev); 288#endif 289 /* 290 * The transport should ensure the visibility of vq->broken 291 * before setting DRIVER_OK. See the comments for the transport 292 * specific set_status() method. 293 * 294 * A well behaved device will only notify a virtqueue after 295 * DRIVER_OK, this means the device should "see" the coherenct 296 * memory write that set vq->broken as false which is done by 297 * the driver when it sees DRIVER_OK, then the following 298 * driver's vring_interrupt() will see vq->broken as false so 299 * we won't lose any notification. 300 */ 301 dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK); 302} 303 304static inline 305const char *virtio_bus_name(struct virtio_device *vdev) 306{ 307 if (!vdev->config->bus_name) 308 return "virtio"; 309 return vdev->config->bus_name(vdev); 310} 311 312/** 313 * virtqueue_set_affinity - setting affinity for a virtqueue 314 * @vq: the virtqueue 315 * @cpu_mask: the cpu mask 316 * 317 * Pay attention the function are best-effort: the affinity hint may not be set 318 * due to config support, irq type and sharing. 319 * 320 */ 321static inline 322int virtqueue_set_affinity(struct virtqueue *vq, const struct cpumask *cpu_mask) 323{ 324 struct virtio_device *vdev = vq->vdev; 325 if (vdev->config->set_vq_affinity) 326 return vdev->config->set_vq_affinity(vq, cpu_mask); 327 return 0; 328} 329 330static inline 331bool virtio_get_shm_region(struct virtio_device *vdev, 332 struct virtio_shm_region *region, u8 id) 333{ 334 if (!vdev->config->get_shm_region) 335 return false; 336 return vdev->config->get_shm_region(vdev, region, id); 337} 338 339static inline bool virtio_is_little_endian(struct virtio_device *vdev) 340{ 341 return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) || 342 virtio_legacy_is_little_endian(); 343} 344 345/* Memory accessors */ 346static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val) 347{ 348 return __virtio16_to_cpu(virtio_is_little_endian(vdev), val); 349} 350 351static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val) 352{ 353 return __cpu_to_virtio16(virtio_is_little_endian(vdev), val); 354} 355 356static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val) 357{ 358 return __virtio32_to_cpu(virtio_is_little_endian(vdev), val); 359} 360 361static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val) 362{ 363 return __cpu_to_virtio32(virtio_is_little_endian(vdev), val); 364} 365 366static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val) 367{ 368 return __virtio64_to_cpu(virtio_is_little_endian(vdev), val); 369} 370 371static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val) 372{ 373 return __cpu_to_virtio64(virtio_is_little_endian(vdev), val); 374} 375 376#define virtio_to_cpu(vdev, x) \ 377 _Generic((x), \ 378 __u8: (x), \ 379 __virtio16: virtio16_to_cpu((vdev), (x)), \ 380 __virtio32: virtio32_to_cpu((vdev), (x)), \ 381 __virtio64: virtio64_to_cpu((vdev), (x)) \ 382 ) 383 384#define cpu_to_virtio(vdev, x, m) \ 385 _Generic((m), \ 386 __u8: (x), \ 387 __virtio16: cpu_to_virtio16((vdev), (x)), \ 388 __virtio32: cpu_to_virtio32((vdev), (x)), \ 389 __virtio64: cpu_to_virtio64((vdev), (x)) \ 390 ) 391 392#define __virtio_native_type(structname, member) \ 393 typeof(virtio_to_cpu(NULL, ((structname*)0)->member)) 394 395/* Config space accessors. */ 396#define virtio_cread(vdev, structname, member, ptr) \ 397 do { \ 398 typeof(((structname*)0)->member) virtio_cread_v; \ 399 \ 400 might_sleep(); \ 401 /* Sanity check: must match the member's type */ \ 402 typecheck(typeof(virtio_to_cpu((vdev), virtio_cread_v)), *(ptr)); \ 403 \ 404 switch (sizeof(virtio_cread_v)) { \ 405 case 1: \ 406 case 2: \ 407 case 4: \ 408 vdev->config->get((vdev), \ 409 offsetof(structname, member), \ 410 &virtio_cread_v, \ 411 sizeof(virtio_cread_v)); \ 412 break; \ 413 default: \ 414 __virtio_cread_many((vdev), \ 415 offsetof(structname, member), \ 416 &virtio_cread_v, \ 417 1, \ 418 sizeof(virtio_cread_v)); \ 419 break; \ 420 } \ 421 *(ptr) = virtio_to_cpu(vdev, virtio_cread_v); \ 422 } while(0) 423 424/* Config space accessors. */ 425#define virtio_cwrite(vdev, structname, member, ptr) \ 426 do { \ 427 typeof(((structname*)0)->member) virtio_cwrite_v = \ 428 cpu_to_virtio(vdev, *(ptr), ((structname*)0)->member); \ 429 \ 430 might_sleep(); \ 431 /* Sanity check: must match the member's type */ \ 432 typecheck(typeof(virtio_to_cpu((vdev), virtio_cwrite_v)), *(ptr)); \ 433 \ 434 vdev->config->set((vdev), offsetof(structname, member), \ 435 &virtio_cwrite_v, \ 436 sizeof(virtio_cwrite_v)); \ 437 } while(0) 438 439/* 440 * Nothing virtio-specific about these, but let's worry about generalizing 441 * these later. 442 */ 443#define virtio_le_to_cpu(x) \ 444 _Generic((x), \ 445 __u8: (u8)(x), \ 446 __le16: (u16)le16_to_cpu(x), \ 447 __le32: (u32)le32_to_cpu(x), \ 448 __le64: (u64)le64_to_cpu(x) \ 449 ) 450 451#define virtio_cpu_to_le(x, m) \ 452 _Generic((m), \ 453 __u8: (x), \ 454 __le16: cpu_to_le16(x), \ 455 __le32: cpu_to_le32(x), \ 456 __le64: cpu_to_le64(x) \ 457 ) 458 459/* LE (e.g. modern) Config space accessors. */ 460#define virtio_cread_le(vdev, structname, member, ptr) \ 461 do { \ 462 typeof(((structname*)0)->member) virtio_cread_v; \ 463 \ 464 might_sleep(); \ 465 /* Sanity check: must match the member's type */ \ 466 typecheck(typeof(virtio_le_to_cpu(virtio_cread_v)), *(ptr)); \ 467 \ 468 switch (sizeof(virtio_cread_v)) { \ 469 case 1: \ 470 case 2: \ 471 case 4: \ 472 vdev->config->get((vdev), \ 473 offsetof(structname, member), \ 474 &virtio_cread_v, \ 475 sizeof(virtio_cread_v)); \ 476 break; \ 477 default: \ 478 __virtio_cread_many((vdev), \ 479 offsetof(structname, member), \ 480 &virtio_cread_v, \ 481 1, \ 482 sizeof(virtio_cread_v)); \ 483 break; \ 484 } \ 485 *(ptr) = virtio_le_to_cpu(virtio_cread_v); \ 486 } while(0) 487 488#define virtio_cwrite_le(vdev, structname, member, ptr) \ 489 do { \ 490 typeof(((structname*)0)->member) virtio_cwrite_v = \ 491 virtio_cpu_to_le(*(ptr), ((structname*)0)->member); \ 492 \ 493 might_sleep(); \ 494 /* Sanity check: must match the member's type */ \ 495 typecheck(typeof(virtio_le_to_cpu(virtio_cwrite_v)), *(ptr)); \ 496 \ 497 vdev->config->set((vdev), offsetof(structname, member), \ 498 &virtio_cwrite_v, \ 499 sizeof(virtio_cwrite_v)); \ 500 } while(0) 501 502 503/* Read @count fields, @bytes each. */ 504static inline void __virtio_cread_many(struct virtio_device *vdev, 505 unsigned int offset, 506 void *buf, size_t count, size_t bytes) 507{ 508 u32 old, gen = vdev->config->generation ? 509 vdev->config->generation(vdev) : 0; 510 int i; 511 512 might_sleep(); 513 do { 514 old = gen; 515 516 for (i = 0; i < count; i++) 517 vdev->config->get(vdev, offset + bytes * i, 518 buf + i * bytes, bytes); 519 520 gen = vdev->config->generation ? 521 vdev->config->generation(vdev) : 0; 522 } while (gen != old); 523} 524 525static inline void virtio_cread_bytes(struct virtio_device *vdev, 526 unsigned int offset, 527 void *buf, size_t len) 528{ 529 __virtio_cread_many(vdev, offset, buf, len, 1); 530} 531 532static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset) 533{ 534 u8 ret; 535 536 might_sleep(); 537 vdev->config->get(vdev, offset, &ret, sizeof(ret)); 538 return ret; 539} 540 541static inline void virtio_cwrite8(struct virtio_device *vdev, 542 unsigned int offset, u8 val) 543{ 544 might_sleep(); 545 vdev->config->set(vdev, offset, &val, sizeof(val)); 546} 547 548static inline u16 virtio_cread16(struct virtio_device *vdev, 549 unsigned int offset) 550{ 551 __virtio16 ret; 552 553 might_sleep(); 554 vdev->config->get(vdev, offset, &ret, sizeof(ret)); 555 return virtio16_to_cpu(vdev, ret); 556} 557 558static inline void virtio_cwrite16(struct virtio_device *vdev, 559 unsigned int offset, u16 val) 560{ 561 __virtio16 v; 562 563 might_sleep(); 564 v = cpu_to_virtio16(vdev, val); 565 vdev->config->set(vdev, offset, &v, sizeof(v)); 566} 567 568static inline u32 virtio_cread32(struct virtio_device *vdev, 569 unsigned int offset) 570{ 571 __virtio32 ret; 572 573 might_sleep(); 574 vdev->config->get(vdev, offset, &ret, sizeof(ret)); 575 return virtio32_to_cpu(vdev, ret); 576} 577 578static inline void virtio_cwrite32(struct virtio_device *vdev, 579 unsigned int offset, u32 val) 580{ 581 __virtio32 v; 582 583 might_sleep(); 584 v = cpu_to_virtio32(vdev, val); 585 vdev->config->set(vdev, offset, &v, sizeof(v)); 586} 587 588static inline u64 virtio_cread64(struct virtio_device *vdev, 589 unsigned int offset) 590{ 591 __virtio64 ret; 592 593 __virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret)); 594 return virtio64_to_cpu(vdev, ret); 595} 596 597static inline void virtio_cwrite64(struct virtio_device *vdev, 598 unsigned int offset, u64 val) 599{ 600 __virtio64 v; 601 602 might_sleep(); 603 v = cpu_to_virtio64(vdev, val); 604 vdev->config->set(vdev, offset, &v, sizeof(v)); 605} 606 607/* Conditional config space accessors. */ 608#define virtio_cread_feature(vdev, fbit, structname, member, ptr) \ 609 ({ \ 610 int _r = 0; \ 611 if (!virtio_has_feature(vdev, fbit)) \ 612 _r = -ENOENT; \ 613 else \ 614 virtio_cread((vdev), structname, member, ptr); \ 615 _r; \ 616 }) 617 618/* Conditional config space accessors. */ 619#define virtio_cread_le_feature(vdev, fbit, structname, member, ptr) \ 620 ({ \ 621 int _r = 0; \ 622 if (!virtio_has_feature(vdev, fbit)) \ 623 _r = -ENOENT; \ 624 else \ 625 virtio_cread_le((vdev), structname, member, ptr); \ 626 _r; \ 627 }) 628 629#endif /* _LINUX_VIRTIO_CONFIG_H */ 630