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