include/linux/virtio_config.h

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