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, 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 */