1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_VIRTIO_CONFIG_H
3 #define _LINUX_VIRTIO_CONFIG_H
7 #include <linux/virtio.h>
8 #include <linux/virtio_byteorder.h>
9 #include <linux/compiler_types.h>
10 #include <uapi/linux/virtio_config.h>
14 struct virtio_shm_region {
20 * virtio_config_ops - operations for configuring a virtio device
21 * Note: Do not assume that a transport implements all of the operations
22 * getting/setting a value as a simple read/write! Generally speaking,
23 * any of @get/@set, @get_status/@set_status, or @get_features/
24 * @finalize_features are NOT safe to be called from an atomic
26 * @get: read the value of a configuration field
27 * vdev: the virtio_device
28 * offset: the offset of the configuration field
29 * buf: the buffer to write the field value into.
30 * len: the length of the buffer
31 * @set: write the value of a configuration field
32 * vdev: the virtio_device
33 * offset: the offset of the configuration field
34 * buf: the buffer to read the field value from.
35 * len: the length of the buffer
36 * @generation: config generation counter (optional)
37 * vdev: the virtio_device
38 * Returns the config generation counter
39 * @get_status: read the status byte
40 * vdev: the virtio_device
41 * Returns the status byte
42 * @set_status: write the status byte
43 * vdev: the virtio_device
44 * status: the new status byte
45 * @reset: reset the device
46 * vdev: the virtio device
47 * After this, status and feature negotiation must be done again
48 * Device must not be reset from its vq/config callbacks, or in
49 * parallel with being added/removed.
50 * @find_vqs: find virtqueues and instantiate them.
51 * vdev: the virtio_device
52 * nvqs: the number of virtqueues to find
53 * vqs: on success, includes new virtqueues
54 * callbacks: array of callbacks, for each virtqueue
55 * include a NULL entry for vqs that do not need a callback
56 * names: array of virtqueue names (mainly for debugging)
57 * include a NULL entry for vqs unused by driver
58 * sizes: array of virtqueue sizes
59 * Returns 0 on success or error status
60 * @del_vqs: free virtqueues found by find_vqs().
61 * @synchronize_cbs: synchronize with the virtqueue callbacks (optional)
62 * The function guarantees that all memory operations on the
63 * queue before it are visible to the vring_interrupt() that is
65 * vdev: the virtio_device
66 * @get_features: get the array of feature bits for this device.
67 * vdev: the virtio_device
68 * Returns the first 64 feature bits (all we currently need).
69 * @finalize_features: confirm what device features we'll be using.
70 * vdev: the virtio_device
71 * This sends the driver feature bits to the device: it can change
72 * the dev->feature bits if it wants.
73 * Note: despite the name this can be called any number of times.
74 * Returns 0 on success or error status
75 * @bus_name: return the bus name associated with the device (optional)
76 * vdev: the virtio_device
77 * This returns a pointer to the bus name a la pci_name from which
78 * the caller can then copy.
79 * @set_vq_affinity: set the affinity for a virtqueue (optional).
80 * @get_vq_affinity: get the affinity for a virtqueue (optional).
81 * @get_shm_region: get a shared memory region based on the index.
82 * @disable_vq_and_reset: reset a queue individually (optional).
84 * Returns 0 on success or error status
85 * disable_vq_and_reset will guarantee that the callbacks are disabled and
87 * Except for the callback, the caller should guarantee that the vring is
88 * not accessed by any functions of virtqueue.
89 * @enable_vq_after_reset: enable a reset queue
91 * Returns 0 on success or error status
92 * If disable_vq_and_reset is set, then enable_vq_after_reset must also be
95 typedef void vq_callback_t(struct virtqueue *);
96 struct virtio_config_ops {
97 void (*get)(struct virtio_device *vdev, unsigned offset,
98 void *buf, unsigned len);
99 void (*set)(struct virtio_device *vdev, unsigned offset,
100 const void *buf, unsigned len);
101 u32 (*generation)(struct virtio_device *vdev);
102 u8 (*get_status)(struct virtio_device *vdev);
103 void (*set_status)(struct virtio_device *vdev, u8 status);
104 void (*reset)(struct virtio_device *vdev);
105 int (*find_vqs)(struct virtio_device *, unsigned nvqs,
106 struct virtqueue *vqs[], vq_callback_t *callbacks[],
107 const char * const names[],
110 struct irq_affinity *desc);
111 void (*del_vqs)(struct virtio_device *);
112 void (*synchronize_cbs)(struct virtio_device *);
113 u64 (*get_features)(struct virtio_device *vdev);
114 int (*finalize_features)(struct virtio_device *vdev);
115 const char *(*bus_name)(struct virtio_device *vdev);
116 int (*set_vq_affinity)(struct virtqueue *vq,
117 const struct cpumask *cpu_mask);
118 const struct cpumask *(*get_vq_affinity)(struct virtio_device *vdev,
120 bool (*get_shm_region)(struct virtio_device *vdev,
121 struct virtio_shm_region *region, u8 id);
122 int (*disable_vq_and_reset)(struct virtqueue *vq);
123 int (*enable_vq_after_reset)(struct virtqueue *vq);
126 /* If driver didn't advertise the feature, it will never appear. */
127 void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
131 * __virtio_test_bit - helper to test feature bits. For use by transports.
132 * Devices should normally use virtio_has_feature,
133 * which includes more checks.
135 * @fbit: the feature bit
137 static inline bool __virtio_test_bit(const struct virtio_device *vdev,
140 /* Did you forget to fix assumptions on max features? */
141 if (__builtin_constant_p(fbit))
142 BUILD_BUG_ON(fbit >= 64);
146 return vdev->features & BIT_ULL(fbit);
150 * __virtio_set_bit - helper to set feature bits. For use by transports.
152 * @fbit: the feature bit
154 static inline void __virtio_set_bit(struct virtio_device *vdev,
157 /* Did you forget to fix assumptions on max features? */
158 if (__builtin_constant_p(fbit))
159 BUILD_BUG_ON(fbit >= 64);
163 vdev->features |= BIT_ULL(fbit);
167 * __virtio_clear_bit - helper to clear feature bits. For use by transports.
169 * @fbit: the feature bit
171 static inline void __virtio_clear_bit(struct virtio_device *vdev,
174 /* Did you forget to fix assumptions on max features? */
175 if (__builtin_constant_p(fbit))
176 BUILD_BUG_ON(fbit >= 64);
180 vdev->features &= ~BIT_ULL(fbit);
184 * virtio_has_feature - helper to determine if this device has this feature.
186 * @fbit: the feature bit
188 static inline bool virtio_has_feature(const struct virtio_device *vdev,
191 if (fbit < VIRTIO_TRANSPORT_F_START)
192 virtio_check_driver_offered_feature(vdev, fbit);
194 return __virtio_test_bit(vdev, fbit);
198 * virtio_has_dma_quirk - determine whether this device has the DMA quirk
201 static inline bool virtio_has_dma_quirk(const struct virtio_device *vdev)
204 * Note the reverse polarity of the quirk feature (compared to most
205 * other features), this is for compatibility with legacy systems.
207 return !virtio_has_feature(vdev, VIRTIO_F_ACCESS_PLATFORM);
211 struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
212 vq_callback_t *c, const char *n)
214 vq_callback_t *callbacks[] = { c };
215 const char *names[] = { n };
216 struct virtqueue *vq;
217 int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names, NULL,
225 int virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
226 struct virtqueue *vqs[], vq_callback_t *callbacks[],
227 const char * const names[],
228 struct irq_affinity *desc)
230 return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, NULL,
235 int virtio_find_vqs_ctx(struct virtio_device *vdev, unsigned nvqs,
236 struct virtqueue *vqs[], vq_callback_t *callbacks[],
237 const char * const names[], const bool *ctx,
238 struct irq_affinity *desc)
240 return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, NULL,
245 int virtio_find_vqs_ctx_size(struct virtio_device *vdev, u32 nvqs,
246 struct virtqueue *vqs[],
247 vq_callback_t *callbacks[],
248 const char * const names[],
250 const bool *ctx, struct irq_affinity *desc)
252 return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, sizes,
257 * virtio_synchronize_cbs - synchronize with virtqueue callbacks
261 void virtio_synchronize_cbs(struct virtio_device *dev)
263 if (dev->config->synchronize_cbs) {
264 dev->config->synchronize_cbs(dev);
267 * A best effort fallback to synchronize with
268 * interrupts, preemption and softirq disabled
269 * regions. See comment above synchronize_rcu().
276 * virtio_device_ready - enable vq use in probe function
279 * Driver must call this to use vqs in the probe function.
281 * Note: vqs are enabled automatically after probe returns.
284 void virtio_device_ready(struct virtio_device *dev)
286 unsigned status = dev->config->get_status(dev);
288 WARN_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
290 #ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION
292 * The virtio_synchronize_cbs() makes sure vring_interrupt()
293 * will see the driver specific setup if it sees vq->broken
294 * as false (even if the notifications come before DRIVER_OK).
296 virtio_synchronize_cbs(dev);
297 __virtio_unbreak_device(dev);
300 * The transport should ensure the visibility of vq->broken
301 * before setting DRIVER_OK. See the comments for the transport
302 * specific set_status() method.
304 * A well behaved device will only notify a virtqueue after
305 * DRIVER_OK, this means the device should "see" the coherenct
306 * memory write that set vq->broken as false which is done by
307 * the driver when it sees DRIVER_OK, then the following
308 * driver's vring_interrupt() will see vq->broken as false so
309 * we won't lose any notification.
311 dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
315 const char *virtio_bus_name(struct virtio_device *vdev)
317 if (!vdev->config->bus_name)
319 return vdev->config->bus_name(vdev);
323 * virtqueue_set_affinity - setting affinity for a virtqueue
327 * Pay attention the function are best-effort: the affinity hint may not be set
328 * due to config support, irq type and sharing.
332 int virtqueue_set_affinity(struct virtqueue *vq, const struct cpumask *cpu_mask)
334 struct virtio_device *vdev = vq->vdev;
335 if (vdev->config->set_vq_affinity)
336 return vdev->config->set_vq_affinity(vq, cpu_mask);
341 bool virtio_get_shm_region(struct virtio_device *vdev,
342 struct virtio_shm_region *region, u8 id)
344 if (!vdev->config->get_shm_region)
346 return vdev->config->get_shm_region(vdev, region, id);
349 static inline bool virtio_is_little_endian(struct virtio_device *vdev)
351 return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
352 virtio_legacy_is_little_endian();
355 /* Memory accessors */
356 static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val)
358 return __virtio16_to_cpu(virtio_is_little_endian(vdev), val);
361 static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val)
363 return __cpu_to_virtio16(virtio_is_little_endian(vdev), val);
366 static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val)
368 return __virtio32_to_cpu(virtio_is_little_endian(vdev), val);
371 static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val)
373 return __cpu_to_virtio32(virtio_is_little_endian(vdev), val);
376 static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val)
378 return __virtio64_to_cpu(virtio_is_little_endian(vdev), val);
381 static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
383 return __cpu_to_virtio64(virtio_is_little_endian(vdev), val);
386 #define virtio_to_cpu(vdev, x) \
389 __virtio16: virtio16_to_cpu((vdev), (x)), \
390 __virtio32: virtio32_to_cpu((vdev), (x)), \
391 __virtio64: virtio64_to_cpu((vdev), (x)) \
394 #define cpu_to_virtio(vdev, x, m) \
397 __virtio16: cpu_to_virtio16((vdev), (x)), \
398 __virtio32: cpu_to_virtio32((vdev), (x)), \
399 __virtio64: cpu_to_virtio64((vdev), (x)) \
402 #define __virtio_native_type(structname, member) \
403 typeof(virtio_to_cpu(NULL, ((structname*)0)->member))
405 /* Config space accessors. */
406 #define virtio_cread(vdev, structname, member, ptr) \
408 typeof(((structname*)0)->member) virtio_cread_v; \
411 /* Sanity check: must match the member's type */ \
412 typecheck(typeof(virtio_to_cpu((vdev), virtio_cread_v)), *(ptr)); \
414 switch (sizeof(virtio_cread_v)) { \
418 vdev->config->get((vdev), \
419 offsetof(structname, member), \
421 sizeof(virtio_cread_v)); \
424 __virtio_cread_many((vdev), \
425 offsetof(structname, member), \
428 sizeof(virtio_cread_v)); \
431 *(ptr) = virtio_to_cpu(vdev, virtio_cread_v); \
434 /* Config space accessors. */
435 #define virtio_cwrite(vdev, structname, member, ptr) \
437 typeof(((structname*)0)->member) virtio_cwrite_v = \
438 cpu_to_virtio(vdev, *(ptr), ((structname*)0)->member); \
441 /* Sanity check: must match the member's type */ \
442 typecheck(typeof(virtio_to_cpu((vdev), virtio_cwrite_v)), *(ptr)); \
444 vdev->config->set((vdev), offsetof(structname, member), \
446 sizeof(virtio_cwrite_v)); \
450 * Nothing virtio-specific about these, but let's worry about generalizing
453 #define virtio_le_to_cpu(x) \
456 __le16: (u16)le16_to_cpu(x), \
457 __le32: (u32)le32_to_cpu(x), \
458 __le64: (u64)le64_to_cpu(x) \
461 #define virtio_cpu_to_le(x, m) \
464 __le16: cpu_to_le16(x), \
465 __le32: cpu_to_le32(x), \
466 __le64: cpu_to_le64(x) \
469 /* LE (e.g. modern) Config space accessors. */
470 #define virtio_cread_le(vdev, structname, member, ptr) \
472 typeof(((structname*)0)->member) virtio_cread_v; \
475 /* Sanity check: must match the member's type */ \
476 typecheck(typeof(virtio_le_to_cpu(virtio_cread_v)), *(ptr)); \
478 switch (sizeof(virtio_cread_v)) { \
482 vdev->config->get((vdev), \
483 offsetof(structname, member), \
485 sizeof(virtio_cread_v)); \
488 __virtio_cread_many((vdev), \
489 offsetof(structname, member), \
492 sizeof(virtio_cread_v)); \
495 *(ptr) = virtio_le_to_cpu(virtio_cread_v); \
498 #define virtio_cwrite_le(vdev, structname, member, ptr) \
500 typeof(((structname*)0)->member) virtio_cwrite_v = \
501 virtio_cpu_to_le(*(ptr), ((structname*)0)->member); \
504 /* Sanity check: must match the member's type */ \
505 typecheck(typeof(virtio_le_to_cpu(virtio_cwrite_v)), *(ptr)); \
507 vdev->config->set((vdev), offsetof(structname, member), \
509 sizeof(virtio_cwrite_v)); \
513 /* Read @count fields, @bytes each. */
514 static inline void __virtio_cread_many(struct virtio_device *vdev,
516 void *buf, size_t count, size_t bytes)
518 u32 old, gen = vdev->config->generation ?
519 vdev->config->generation(vdev) : 0;
526 for (i = 0; i < count; i++)
527 vdev->config->get(vdev, offset + bytes * i,
528 buf + i * bytes, bytes);
530 gen = vdev->config->generation ?
531 vdev->config->generation(vdev) : 0;
532 } while (gen != old);
535 static inline void virtio_cread_bytes(struct virtio_device *vdev,
537 void *buf, size_t len)
539 __virtio_cread_many(vdev, offset, buf, len, 1);
542 static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
547 vdev->config->get(vdev, offset, &ret, sizeof(ret));
551 static inline void virtio_cwrite8(struct virtio_device *vdev,
552 unsigned int offset, u8 val)
555 vdev->config->set(vdev, offset, &val, sizeof(val));
558 static inline u16 virtio_cread16(struct virtio_device *vdev,
564 vdev->config->get(vdev, offset, &ret, sizeof(ret));
565 return virtio16_to_cpu(vdev, ret);
568 static inline void virtio_cwrite16(struct virtio_device *vdev,
569 unsigned int offset, u16 val)
574 v = cpu_to_virtio16(vdev, val);
575 vdev->config->set(vdev, offset, &v, sizeof(v));
578 static inline u32 virtio_cread32(struct virtio_device *vdev,
584 vdev->config->get(vdev, offset, &ret, sizeof(ret));
585 return virtio32_to_cpu(vdev, ret);
588 static inline void virtio_cwrite32(struct virtio_device *vdev,
589 unsigned int offset, u32 val)
594 v = cpu_to_virtio32(vdev, val);
595 vdev->config->set(vdev, offset, &v, sizeof(v));
598 static inline u64 virtio_cread64(struct virtio_device *vdev,
603 __virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret));
604 return virtio64_to_cpu(vdev, ret);
607 static inline void virtio_cwrite64(struct virtio_device *vdev,
608 unsigned int offset, u64 val)
613 v = cpu_to_virtio64(vdev, val);
614 vdev->config->set(vdev, offset, &v, sizeof(v));
617 /* Conditional config space accessors. */
618 #define virtio_cread_feature(vdev, fbit, structname, member, ptr) \
621 if (!virtio_has_feature(vdev, fbit)) \
624 virtio_cread((vdev), structname, member, ptr); \
628 /* Conditional config space accessors. */
629 #define virtio_cread_le_feature(vdev, fbit, structname, member, ptr) \
632 if (!virtio_has_feature(vdev, fbit)) \
635 virtio_cread_le((vdev), structname, member, ptr); \
639 #endif /* _LINUX_VIRTIO_CONFIG_H */