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 <uapi/linux/virtio_config.h> 10 11 struct irq_affinity; 12 13 /** 14 * virtio_config_ops - operations for configuring a virtio device 15 * Note: Do not assume that a transport implements all of the operations 16 * getting/setting a value as a simple read/write! Generally speaking, 17 * any of @get/@set, @get_status/@set_status, or @get_features/ 18 * @finalize_features are NOT safe to be called from an atomic 19 * context. 20 * @get: read the value of a configuration field 21 * vdev: the virtio_device 22 * offset: the offset of the configuration field 23 * buf: the buffer to write the field value into. 24 * len: the length of the buffer 25 * @set: write the value of a configuration field 26 * vdev: the virtio_device 27 * offset: the offset of the configuration field 28 * buf: the buffer to read the field value from. 29 * len: the length of the buffer 30 * @generation: config generation counter (optional) 31 * vdev: the virtio_device 32 * Returns the config generation counter 33 * @get_status: read the status byte 34 * vdev: the virtio_device 35 * Returns the status byte 36 * @set_status: write the status byte 37 * vdev: the virtio_device 38 * status: the new status byte 39 * @reset: reset the device 40 * vdev: the virtio device 41 * After this, status and feature negotiation must be done again 42 * Device must not be reset from its vq/config callbacks, or in 43 * parallel with being added/removed. 44 * @find_vqs: find virtqueues and instantiate them. 45 * vdev: the virtio_device 46 * nvqs: the number of virtqueues to find 47 * vqs: on success, includes new virtqueues 48 * callbacks: array of callbacks, for each virtqueue 49 * include a NULL entry for vqs that do not need a callback 50 * names: array of virtqueue names (mainly for debugging) 51 * include a NULL entry for vqs unused by driver 52 * Returns 0 on success or error status 53 * @del_vqs: free virtqueues found by find_vqs(). 54 * @get_features: get the array of feature bits for this device. 55 * vdev: the virtio_device 56 * Returns the first 64 feature bits (all we currently need). 57 * @finalize_features: confirm what device features we'll be using. 58 * vdev: the virtio_device 59 * This gives the final feature bits for the device: it can change 60 * the dev->feature bits if it wants. 61 * Returns 0 on success or error status 62 * @bus_name: return the bus name associated with the device (optional) 63 * vdev: the virtio_device 64 * This returns a pointer to the bus name a la pci_name from which 65 * the caller can then copy. 66 * @set_vq_affinity: set the affinity for a virtqueue (optional). 67 * @get_vq_affinity: get the affinity for a virtqueue (optional). 68 */ 69 typedef void vq_callback_t(struct virtqueue *); 70 struct virtio_config_ops { 71 void (*get)(struct virtio_device *vdev, unsigned offset, 72 void *buf, unsigned len); 73 void (*set)(struct virtio_device *vdev, unsigned offset, 74 const void *buf, unsigned len); 75 u32 (*generation)(struct virtio_device *vdev); 76 u8 (*get_status)(struct virtio_device *vdev); 77 void (*set_status)(struct virtio_device *vdev, u8 status); 78 void (*reset)(struct virtio_device *vdev); 79 int (*find_vqs)(struct virtio_device *, unsigned nvqs, 80 struct virtqueue *vqs[], vq_callback_t *callbacks[], 81 const char * const names[], const bool *ctx, 82 struct irq_affinity *desc); 83 void (*del_vqs)(struct virtio_device *); 84 u64 (*get_features)(struct virtio_device *vdev); 85 int (*finalize_features)(struct virtio_device *vdev); 86 const char *(*bus_name)(struct virtio_device *vdev); 87 int (*set_vq_affinity)(struct virtqueue *vq, 88 const struct cpumask *cpu_mask); 89 const struct cpumask *(*get_vq_affinity)(struct virtio_device *vdev, 90 int index); 91 }; 92 93 /* If driver didn't advertise the feature, it will never appear. */ 94 void virtio_check_driver_offered_feature(const struct virtio_device *vdev, 95 unsigned int fbit); 96 97 /** 98 * __virtio_test_bit - helper to test feature bits. For use by transports. 99 * Devices should normally use virtio_has_feature, 100 * which includes more checks. 101 * @vdev: the device 102 * @fbit: the feature bit 103 */ 104 static inline bool __virtio_test_bit(const struct virtio_device *vdev, 105 unsigned int fbit) 106 { 107 /* Did you forget to fix assumptions on max features? */ 108 if (__builtin_constant_p(fbit)) 109 BUILD_BUG_ON(fbit >= 64); 110 else 111 BUG_ON(fbit >= 64); 112 113 return vdev->features & BIT_ULL(fbit); 114 } 115 116 /** 117 * __virtio_set_bit - helper to set feature bits. For use by transports. 118 * @vdev: the device 119 * @fbit: the feature bit 120 */ 121 static inline void __virtio_set_bit(struct virtio_device *vdev, 122 unsigned int fbit) 123 { 124 /* Did you forget to fix assumptions on max features? */ 125 if (__builtin_constant_p(fbit)) 126 BUILD_BUG_ON(fbit >= 64); 127 else 128 BUG_ON(fbit >= 64); 129 130 vdev->features |= BIT_ULL(fbit); 131 } 132 133 /** 134 * __virtio_clear_bit - helper to clear feature bits. For use by transports. 135 * @vdev: the device 136 * @fbit: the feature bit 137 */ 138 static inline void __virtio_clear_bit(struct virtio_device *vdev, 139 unsigned int fbit) 140 { 141 /* Did you forget to fix assumptions on max features? */ 142 if (__builtin_constant_p(fbit)) 143 BUILD_BUG_ON(fbit >= 64); 144 else 145 BUG_ON(fbit >= 64); 146 147 vdev->features &= ~BIT_ULL(fbit); 148 } 149 150 /** 151 * virtio_has_feature - helper to determine if this device has this feature. 152 * @vdev: the device 153 * @fbit: the feature bit 154 */ 155 static inline bool virtio_has_feature(const struct virtio_device *vdev, 156 unsigned int fbit) 157 { 158 if (fbit < VIRTIO_TRANSPORT_F_START) 159 virtio_check_driver_offered_feature(vdev, fbit); 160 161 return __virtio_test_bit(vdev, fbit); 162 } 163 164 /** 165 * virtio_has_iommu_quirk - determine whether this device has the iommu quirk 166 * @vdev: the device 167 */ 168 static inline bool virtio_has_iommu_quirk(const struct virtio_device *vdev) 169 { 170 /* 171 * Note the reverse polarity of the quirk feature (compared to most 172 * other features), this is for compatibility with legacy systems. 173 */ 174 return !virtio_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM); 175 } 176 177 static inline 178 struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev, 179 vq_callback_t *c, const char *n) 180 { 181 vq_callback_t *callbacks[] = { c }; 182 const char *names[] = { n }; 183 struct virtqueue *vq; 184 int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names, NULL, 185 NULL); 186 if (err < 0) 187 return ERR_PTR(err); 188 return vq; 189 } 190 191 static inline 192 int virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs, 193 struct virtqueue *vqs[], vq_callback_t *callbacks[], 194 const char * const names[], 195 struct irq_affinity *desc) 196 { 197 return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, NULL, desc); 198 } 199 200 static inline 201 int virtio_find_vqs_ctx(struct virtio_device *vdev, unsigned nvqs, 202 struct virtqueue *vqs[], vq_callback_t *callbacks[], 203 const char * const names[], const bool *ctx, 204 struct irq_affinity *desc) 205 { 206 return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, ctx, 207 desc); 208 } 209 210 /** 211 * virtio_device_ready - enable vq use in probe function 212 * @vdev: the device 213 * 214 * Driver must call this to use vqs in the probe function. 215 * 216 * Note: vqs are enabled automatically after probe returns. 217 */ 218 static inline 219 void virtio_device_ready(struct virtio_device *dev) 220 { 221 unsigned status = dev->config->get_status(dev); 222 223 BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK); 224 dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK); 225 } 226 227 static inline 228 const char *virtio_bus_name(struct virtio_device *vdev) 229 { 230 if (!vdev->config->bus_name) 231 return "virtio"; 232 return vdev->config->bus_name(vdev); 233 } 234 235 /** 236 * virtqueue_set_affinity - setting affinity for a virtqueue 237 * @vq: the virtqueue 238 * @cpu: the cpu no. 239 * 240 * Pay attention the function are best-effort: the affinity hint may not be set 241 * due to config support, irq type and sharing. 242 * 243 */ 244 static inline 245 int virtqueue_set_affinity(struct virtqueue *vq, const struct cpumask *cpu_mask) 246 { 247 struct virtio_device *vdev = vq->vdev; 248 if (vdev->config->set_vq_affinity) 249 return vdev->config->set_vq_affinity(vq, cpu_mask); 250 return 0; 251 } 252 253 static inline bool virtio_is_little_endian(struct virtio_device *vdev) 254 { 255 return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) || 256 virtio_legacy_is_little_endian(); 257 } 258 259 /* Memory accessors */ 260 static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val) 261 { 262 return __virtio16_to_cpu(virtio_is_little_endian(vdev), val); 263 } 264 265 static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val) 266 { 267 return __cpu_to_virtio16(virtio_is_little_endian(vdev), val); 268 } 269 270 static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val) 271 { 272 return __virtio32_to_cpu(virtio_is_little_endian(vdev), val); 273 } 274 275 static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val) 276 { 277 return __cpu_to_virtio32(virtio_is_little_endian(vdev), val); 278 } 279 280 static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val) 281 { 282 return __virtio64_to_cpu(virtio_is_little_endian(vdev), val); 283 } 284 285 static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val) 286 { 287 return __cpu_to_virtio64(virtio_is_little_endian(vdev), val); 288 } 289 290 /* Config space accessors. */ 291 #define virtio_cread(vdev, structname, member, ptr) \ 292 do { \ 293 might_sleep(); \ 294 /* Must match the member's type, and be integer */ \ 295 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \ 296 (*ptr) = 1; \ 297 \ 298 switch (sizeof(*ptr)) { \ 299 case 1: \ 300 *(ptr) = virtio_cread8(vdev, \ 301 offsetof(structname, member)); \ 302 break; \ 303 case 2: \ 304 *(ptr) = virtio_cread16(vdev, \ 305 offsetof(structname, member)); \ 306 break; \ 307 case 4: \ 308 *(ptr) = virtio_cread32(vdev, \ 309 offsetof(structname, member)); \ 310 break; \ 311 case 8: \ 312 *(ptr) = virtio_cread64(vdev, \ 313 offsetof(structname, member)); \ 314 break; \ 315 default: \ 316 BUG(); \ 317 } \ 318 } while(0) 319 320 /* Config space accessors. */ 321 #define virtio_cwrite(vdev, structname, member, ptr) \ 322 do { \ 323 might_sleep(); \ 324 /* Must match the member's type, and be integer */ \ 325 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \ 326 BUG_ON((*ptr) == 1); \ 327 \ 328 switch (sizeof(*ptr)) { \ 329 case 1: \ 330 virtio_cwrite8(vdev, \ 331 offsetof(structname, member), \ 332 *(ptr)); \ 333 break; \ 334 case 2: \ 335 virtio_cwrite16(vdev, \ 336 offsetof(structname, member), \ 337 *(ptr)); \ 338 break; \ 339 case 4: \ 340 virtio_cwrite32(vdev, \ 341 offsetof(structname, member), \ 342 *(ptr)); \ 343 break; \ 344 case 8: \ 345 virtio_cwrite64(vdev, \ 346 offsetof(structname, member), \ 347 *(ptr)); \ 348 break; \ 349 default: \ 350 BUG(); \ 351 } \ 352 } while(0) 353 354 /* Read @count fields, @bytes each. */ 355 static inline void __virtio_cread_many(struct virtio_device *vdev, 356 unsigned int offset, 357 void *buf, size_t count, size_t bytes) 358 { 359 u32 old, gen = vdev->config->generation ? 360 vdev->config->generation(vdev) : 0; 361 int i; 362 363 might_sleep(); 364 do { 365 old = gen; 366 367 for (i = 0; i < count; i++) 368 vdev->config->get(vdev, offset + bytes * i, 369 buf + i * bytes, bytes); 370 371 gen = vdev->config->generation ? 372 vdev->config->generation(vdev) : 0; 373 } while (gen != old); 374 } 375 376 static inline void virtio_cread_bytes(struct virtio_device *vdev, 377 unsigned int offset, 378 void *buf, size_t len) 379 { 380 __virtio_cread_many(vdev, offset, buf, len, 1); 381 } 382 383 static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset) 384 { 385 u8 ret; 386 387 might_sleep(); 388 vdev->config->get(vdev, offset, &ret, sizeof(ret)); 389 return ret; 390 } 391 392 static inline void virtio_cwrite8(struct virtio_device *vdev, 393 unsigned int offset, u8 val) 394 { 395 might_sleep(); 396 vdev->config->set(vdev, offset, &val, sizeof(val)); 397 } 398 399 static inline u16 virtio_cread16(struct virtio_device *vdev, 400 unsigned int offset) 401 { 402 u16 ret; 403 404 might_sleep(); 405 vdev->config->get(vdev, offset, &ret, sizeof(ret)); 406 return virtio16_to_cpu(vdev, (__force __virtio16)ret); 407 } 408 409 static inline void virtio_cwrite16(struct virtio_device *vdev, 410 unsigned int offset, u16 val) 411 { 412 might_sleep(); 413 val = (__force u16)cpu_to_virtio16(vdev, val); 414 vdev->config->set(vdev, offset, &val, sizeof(val)); 415 } 416 417 static inline u32 virtio_cread32(struct virtio_device *vdev, 418 unsigned int offset) 419 { 420 u32 ret; 421 422 might_sleep(); 423 vdev->config->get(vdev, offset, &ret, sizeof(ret)); 424 return virtio32_to_cpu(vdev, (__force __virtio32)ret); 425 } 426 427 static inline void virtio_cwrite32(struct virtio_device *vdev, 428 unsigned int offset, u32 val) 429 { 430 might_sleep(); 431 val = (__force u32)cpu_to_virtio32(vdev, val); 432 vdev->config->set(vdev, offset, &val, sizeof(val)); 433 } 434 435 static inline u64 virtio_cread64(struct virtio_device *vdev, 436 unsigned int offset) 437 { 438 u64 ret; 439 __virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret)); 440 return virtio64_to_cpu(vdev, (__force __virtio64)ret); 441 } 442 443 static inline void virtio_cwrite64(struct virtio_device *vdev, 444 unsigned int offset, u64 val) 445 { 446 might_sleep(); 447 val = (__force u64)cpu_to_virtio64(vdev, val); 448 vdev->config->set(vdev, offset, &val, sizeof(val)); 449 } 450 451 /* Conditional config space accessors. */ 452 #define virtio_cread_feature(vdev, fbit, structname, member, ptr) \ 453 ({ \ 454 int _r = 0; \ 455 if (!virtio_has_feature(vdev, fbit)) \ 456 _r = -ENOENT; \ 457 else \ 458 virtio_cread((vdev), structname, member, ptr); \ 459 _r; \ 460 }) 461 462 #endif /* _LINUX_VIRTIO_CONFIG_H */ 463