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 <uapi/linux/virtio_config.h>
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 sends the driver feature bits to the device: it can change
55 * the dev->feature bits if it wants.
56 * Note: despite the name this can be called any number of times.
57 * Returns 0 on success or error status
58 * @bus_name: return the bus name associated with the device
59 * vdev: the virtio_device
60 * This returns a pointer to the bus name a la pci_name from which
61 * the caller can then copy.
62 * @set_vq_affinity: set the affinity for a virtqueue.
63 * @get_vq_affinity: get the affinity for a virtqueue (optional).
65 typedef void vq_callback_t(struct virtqueue *);
66 struct virtio_config_ops {
67 void (*get)(struct virtio_device *vdev, unsigned offset,
68 void *buf, unsigned len);
69 void (*set)(struct virtio_device *vdev, unsigned offset,
70 const void *buf, unsigned len);
71 u32 (*generation)(struct virtio_device *vdev);
72 u8 (*get_status)(struct virtio_device *vdev);
73 void (*set_status)(struct virtio_device *vdev, u8 status);
74 void (*reset)(struct virtio_device *vdev);
75 int (*find_vqs)(struct virtio_device *, unsigned nvqs,
76 struct virtqueue *vqs[], vq_callback_t *callbacks[],
77 const char * const names[], const bool *ctx,
78 struct irq_affinity *desc);
79 void (*del_vqs)(struct virtio_device *);
80 u64 (*get_features)(struct virtio_device *vdev);
81 int (*finalize_features)(struct virtio_device *vdev);
82 const char *(*bus_name)(struct virtio_device *vdev);
83 int (*set_vq_affinity)(struct virtqueue *vq,
84 const struct cpumask *cpu_mask);
85 const struct cpumask *(*get_vq_affinity)(struct virtio_device *vdev,
89 /* If driver didn't advertise the feature, it will never appear. */
90 void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
94 * __virtio_test_bit - helper to test feature bits. For use by transports.
95 * Devices should normally use virtio_has_feature,
96 * which includes more checks.
98 * @fbit: the feature bit
100 static inline bool __virtio_test_bit(const struct virtio_device *vdev,
103 /* Did you forget to fix assumptions on max features? */
104 if (__builtin_constant_p(fbit))
105 BUILD_BUG_ON(fbit >= 64);
109 return vdev->features & BIT_ULL(fbit);
113 * __virtio_set_bit - helper to set feature bits. For use by transports.
115 * @fbit: the feature bit
117 static inline void __virtio_set_bit(struct virtio_device *vdev,
120 /* Did you forget to fix assumptions on max features? */
121 if (__builtin_constant_p(fbit))
122 BUILD_BUG_ON(fbit >= 64);
126 vdev->features |= BIT_ULL(fbit);
130 * __virtio_clear_bit - helper to clear feature bits. For use by transports.
132 * @fbit: the feature bit
134 static inline void __virtio_clear_bit(struct virtio_device *vdev,
137 /* Did you forget to fix assumptions on max features? */
138 if (__builtin_constant_p(fbit))
139 BUILD_BUG_ON(fbit >= 64);
143 vdev->features &= ~BIT_ULL(fbit);
147 * virtio_has_feature - helper to determine if this device has this feature.
149 * @fbit: the feature bit
151 static inline bool virtio_has_feature(const struct virtio_device *vdev,
154 if (fbit < VIRTIO_TRANSPORT_F_START)
155 virtio_check_driver_offered_feature(vdev, fbit);
157 return __virtio_test_bit(vdev, fbit);
161 * virtio_has_iommu_quirk - determine whether this device has the iommu quirk
164 static inline bool virtio_has_iommu_quirk(const struct virtio_device *vdev)
167 * Note the reverse polarity of the quirk feature (compared to most
168 * other features), this is for compatibility with legacy systems.
170 return !virtio_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM);
174 struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
175 vq_callback_t *c, const char *n)
177 vq_callback_t *callbacks[] = { c };
178 const char *names[] = { n };
179 struct virtqueue *vq;
180 int err = vdev->config->find_vqs(vdev, 1, &vq, callbacks, names, NULL,
188 int virtio_find_vqs(struct virtio_device *vdev, unsigned nvqs,
189 struct virtqueue *vqs[], vq_callback_t *callbacks[],
190 const char * const names[],
191 struct irq_affinity *desc)
193 return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, NULL, desc);
197 int virtio_find_vqs_ctx(struct virtio_device *vdev, unsigned nvqs,
198 struct virtqueue *vqs[], vq_callback_t *callbacks[],
199 const char * const names[], const bool *ctx,
200 struct irq_affinity *desc)
202 return vdev->config->find_vqs(vdev, nvqs, vqs, callbacks, names, ctx,
207 * virtio_device_ready - enable vq use in probe function
210 * Driver must call this to use vqs in the probe function.
212 * Note: vqs are enabled automatically after probe returns.
215 void virtio_device_ready(struct virtio_device *dev)
217 unsigned status = dev->config->get_status(dev);
219 BUG_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
220 dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
224 const char *virtio_bus_name(struct virtio_device *vdev)
226 if (!vdev->config->bus_name)
228 return vdev->config->bus_name(vdev);
232 * virtqueue_set_affinity - setting affinity for a virtqueue
236 * Pay attention the function are best-effort: the affinity hint may not be set
237 * due to config support, irq type and sharing.
241 int virtqueue_set_affinity(struct virtqueue *vq, const struct cpumask *cpu_mask)
243 struct virtio_device *vdev = vq->vdev;
244 if (vdev->config->set_vq_affinity)
245 return vdev->config->set_vq_affinity(vq, cpu_mask);
249 static inline bool virtio_is_little_endian(struct virtio_device *vdev)
251 return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
252 virtio_legacy_is_little_endian();
255 /* Memory accessors */
256 static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val)
258 return __virtio16_to_cpu(virtio_is_little_endian(vdev), val);
261 static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val)
263 return __cpu_to_virtio16(virtio_is_little_endian(vdev), val);
266 static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val)
268 return __virtio32_to_cpu(virtio_is_little_endian(vdev), val);
271 static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val)
273 return __cpu_to_virtio32(virtio_is_little_endian(vdev), val);
276 static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val)
278 return __virtio64_to_cpu(virtio_is_little_endian(vdev), val);
281 static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
283 return __cpu_to_virtio64(virtio_is_little_endian(vdev), val);
286 /* Config space accessors. */
287 #define virtio_cread(vdev, structname, member, ptr) \
289 /* Must match the member's type, and be integer */ \
290 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
293 switch (sizeof(*ptr)) { \
295 *(ptr) = virtio_cread8(vdev, \
296 offsetof(structname, member)); \
299 *(ptr) = virtio_cread16(vdev, \
300 offsetof(structname, member)); \
303 *(ptr) = virtio_cread32(vdev, \
304 offsetof(structname, member)); \
307 *(ptr) = virtio_cread64(vdev, \
308 offsetof(structname, member)); \
315 /* Config space accessors. */
316 #define virtio_cwrite(vdev, structname, member, ptr) \
318 /* Must match the member's type, and be integer */ \
319 if (!typecheck(typeof((((structname*)0)->member)), *(ptr))) \
320 BUG_ON((*ptr) == 1); \
322 switch (sizeof(*ptr)) { \
324 virtio_cwrite8(vdev, \
325 offsetof(structname, member), \
329 virtio_cwrite16(vdev, \
330 offsetof(structname, member), \
334 virtio_cwrite32(vdev, \
335 offsetof(structname, member), \
339 virtio_cwrite64(vdev, \
340 offsetof(structname, member), \
348 /* Read @count fields, @bytes each. */
349 static inline void __virtio_cread_many(struct virtio_device *vdev,
351 void *buf, size_t count, size_t bytes)
353 u32 old, gen = vdev->config->generation ?
354 vdev->config->generation(vdev) : 0;
360 for (i = 0; i < count; i++)
361 vdev->config->get(vdev, offset + bytes * i,
362 buf + i * bytes, bytes);
364 gen = vdev->config->generation ?
365 vdev->config->generation(vdev) : 0;
366 } while (gen != old);
369 static inline void virtio_cread_bytes(struct virtio_device *vdev,
371 void *buf, size_t len)
373 __virtio_cread_many(vdev, offset, buf, len, 1);
376 static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
379 vdev->config->get(vdev, offset, &ret, sizeof(ret));
383 static inline void virtio_cwrite8(struct virtio_device *vdev,
384 unsigned int offset, u8 val)
386 vdev->config->set(vdev, offset, &val, sizeof(val));
389 static inline u16 virtio_cread16(struct virtio_device *vdev,
393 vdev->config->get(vdev, offset, &ret, sizeof(ret));
394 return virtio16_to_cpu(vdev, (__force __virtio16)ret);
397 static inline void virtio_cwrite16(struct virtio_device *vdev,
398 unsigned int offset, u16 val)
400 val = (__force u16)cpu_to_virtio16(vdev, val);
401 vdev->config->set(vdev, offset, &val, sizeof(val));
404 static inline u32 virtio_cread32(struct virtio_device *vdev,
408 vdev->config->get(vdev, offset, &ret, sizeof(ret));
409 return virtio32_to_cpu(vdev, (__force __virtio32)ret);
412 static inline void virtio_cwrite32(struct virtio_device *vdev,
413 unsigned int offset, u32 val)
415 val = (__force u32)cpu_to_virtio32(vdev, val);
416 vdev->config->set(vdev, offset, &val, sizeof(val));
419 static inline u64 virtio_cread64(struct virtio_device *vdev,
423 __virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret));
424 return virtio64_to_cpu(vdev, (__force __virtio64)ret);
427 static inline void virtio_cwrite64(struct virtio_device *vdev,
428 unsigned int offset, u64 val)
430 val = (__force u64)cpu_to_virtio64(vdev, val);
431 vdev->config->set(vdev, offset, &val, sizeof(val));
434 /* Conditional config space accessors. */
435 #define virtio_cread_feature(vdev, fbit, structname, member, ptr) \
438 if (!virtio_has_feature(vdev, fbit)) \
441 virtio_cread((vdev), structname, member, ptr); \
445 #endif /* _LINUX_VIRTIO_CONFIG_H */