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 <linux/compiler_types.h>
10 #include <uapi/linux/virtio_config.h>
11
12 struct irq_affinity;
13
14 struct virtio_shm_region {
15 u64 addr;
16 u64 len;
17 };
18
19 typedef void vq_callback_t(struct virtqueue *);
20
21 /**
22 * struct virtqueue_info - Info for a virtqueue passed to find_vqs().
23 * @name: virtqueue description. Used mainly for debugging, NULL for
24 * a virtqueue unused by the driver.
25 * @callback: A callback to invoke on a used buffer notification.
26 * NULL for a virtqueue that does not need a callback.
27 * @ctx: A flag to indicate to maintain an extra context per virtqueue.
28 */
29 struct virtqueue_info {
30 const char *name;
31 vq_callback_t *callback;
32 bool ctx;
33 };
34
35 /**
36 * struct virtio_config_ops - operations for configuring a virtio device
37 * Note: Do not assume that a transport implements all of the operations
38 * getting/setting a value as a simple read/write! Generally speaking,
39 * any of @get/@set, @get_status/@set_status, or @get_features/
40 * @finalize_features are NOT safe to be called from an atomic
41 * context.
42 * @get: read the value of a configuration field
43 * vdev: the virtio_device
44 * offset: the offset of the configuration field
45 * buf: the buffer to write the field value into.
46 * len: the length of the buffer
47 * @set: write the value of a configuration field
48 * vdev: the virtio_device
49 * offset: the offset of the configuration field
50 * buf: the buffer to read the field value from.
51 * len: the length of the buffer
52 * @generation: config generation counter (optional)
53 * vdev: the virtio_device
54 * Returns the config generation counter
55 * @get_status: read the status byte
56 * vdev: the virtio_device
57 * Returns the status byte
58 * @set_status: write the status byte
59 * vdev: the virtio_device
60 * status: the new status byte
61 * @reset: reset the device
62 * vdev: the virtio device
63 * After this, status and feature negotiation must be done again
64 * Device must not be reset from its vq/config callbacks, or in
65 * parallel with being added/removed.
66 * @find_vqs: find virtqueues and instantiate them.
67 * vdev: the virtio_device
68 * nvqs: the number of virtqueues to find
69 * vqs: on success, includes new virtqueues
70 * vqs_info: array of virtqueue info structures
71 * Returns 0 on success or error status
72 * @del_vqs: free virtqueues found by find_vqs().
73 * @synchronize_cbs: synchronize with the virtqueue callbacks (optional)
74 * The function guarantees that all memory operations on the
75 * queue before it are visible to the vring_interrupt() that is
76 * called after it.
77 * vdev: the virtio_device
78 * @get_features: get the array of feature bits for this device.
79 * vdev: the virtio_device
80 * Returns the first 64 feature bits (all we currently need).
81 * @finalize_features: confirm what device features we'll be using.
82 * vdev: the virtio_device
83 * This sends the driver feature bits to the device: it can change
84 * the dev->feature bits if it wants.
85 * Note that despite the name this can be called any number of
86 * times.
87 * Returns 0 on success or error status
88 * @bus_name: return the bus name associated with the device (optional)
89 * vdev: the virtio_device
90 * This returns a pointer to the bus name a la pci_name from which
91 * the caller can then copy.
92 * @set_vq_affinity: set the affinity for a virtqueue (optional).
93 * @get_vq_affinity: get the affinity for a virtqueue (optional).
94 * @get_shm_region: get a shared memory region based on the index.
95 * @disable_vq_and_reset: reset a queue individually (optional).
96 * vq: the virtqueue
97 * Returns 0 on success or error status
98 * disable_vq_and_reset will guarantee that the callbacks are disabled and
99 * synchronized.
100 * Except for the callback, the caller should guarantee that the vring is
101 * not accessed by any functions of virtqueue.
102 * @enable_vq_after_reset: enable a reset queue
103 * vq: the virtqueue
104 * Returns 0 on success or error status
105 * If disable_vq_and_reset is set, then enable_vq_after_reset must also be
106 * set.
107 */
108 struct virtio_config_ops {
109 void (*get)(struct virtio_device *vdev, unsigned offset,
110 void *buf, unsigned len);
111 void (*set)(struct virtio_device *vdev, unsigned offset,
112 const void *buf, unsigned len);
113 u32 (*generation)(struct virtio_device *vdev);
114 u8 (*get_status)(struct virtio_device *vdev);
115 void (*set_status)(struct virtio_device *vdev, u8 status);
116 void (*reset)(struct virtio_device *vdev);
117 int (*find_vqs)(struct virtio_device *vdev, unsigned int nvqs,
118 struct virtqueue *vqs[],
119 struct virtqueue_info vqs_info[],
120 struct irq_affinity *desc);
121 void (*del_vqs)(struct virtio_device *);
122 void (*synchronize_cbs)(struct virtio_device *);
123 u64 (*get_features)(struct virtio_device *vdev);
124 int (*finalize_features)(struct virtio_device *vdev);
125 const char *(*bus_name)(struct virtio_device *vdev);
126 int (*set_vq_affinity)(struct virtqueue *vq,
127 const struct cpumask *cpu_mask);
128 const struct cpumask *(*get_vq_affinity)(struct virtio_device *vdev,
129 int index);
130 bool (*get_shm_region)(struct virtio_device *vdev,
131 struct virtio_shm_region *region, u8 id);
132 int (*disable_vq_and_reset)(struct virtqueue *vq);
133 int (*enable_vq_after_reset)(struct virtqueue *vq);
134 };
135
136 /* If driver didn't advertise the feature, it will never appear. */
137 void virtio_check_driver_offered_feature(const struct virtio_device *vdev,
138 unsigned int fbit);
139
140 /**
141 * __virtio_test_bit - helper to test feature bits. For use by transports.
142 * Devices should normally use virtio_has_feature,
143 * which includes more checks.
144 * @vdev: the device
145 * @fbit: the feature bit
146 */
147 static inline bool __virtio_test_bit(const struct virtio_device *vdev,
148 unsigned int fbit)
149 {
150 /* Did you forget to fix assumptions on max features? */
151 if (__builtin_constant_p(fbit))
152 BUILD_BUG_ON(fbit >= 64);
153 else
154 BUG_ON(fbit >= 64);
155
156 return vdev->features & BIT_ULL(fbit);
157 }
158
159 /**
160 * __virtio_set_bit - helper to set feature bits. For use by transports.
161 * @vdev: the device
162 * @fbit: the feature bit
163 */
164 static inline void __virtio_set_bit(struct virtio_device *vdev,
165 unsigned int fbit)
166 {
167 /* Did you forget to fix assumptions on max features? */
168 if (__builtin_constant_p(fbit))
169 BUILD_BUG_ON(fbit >= 64);
170 else
171 BUG_ON(fbit >= 64);
172
173 vdev->features |= BIT_ULL(fbit);
174 }
175
176 /**
177 * __virtio_clear_bit - helper to clear feature bits. For use by transports.
178 * @vdev: the device
179 * @fbit: the feature bit
180 */
181 static inline void __virtio_clear_bit(struct virtio_device *vdev,
182 unsigned int fbit)
183 {
184 /* Did you forget to fix assumptions on max features? */
185 if (__builtin_constant_p(fbit))
186 BUILD_BUG_ON(fbit >= 64);
187 else
188 BUG_ON(fbit >= 64);
189
190 vdev->features &= ~BIT_ULL(fbit);
191 }
192
193 /**
194 * virtio_has_feature - helper to determine if this device has this feature.
195 * @vdev: the device
196 * @fbit: the feature bit
197 */
198 static inline bool virtio_has_feature(const struct virtio_device *vdev,
199 unsigned int fbit)
200 {
201 if (fbit < VIRTIO_TRANSPORT_F_START)
202 virtio_check_driver_offered_feature(vdev, fbit);
203
204 return __virtio_test_bit(vdev, fbit);
205 }
206
207 /**
208 * virtio_has_dma_quirk - determine whether this device has the DMA quirk
209 * @vdev: the device
210 */
211 static inline bool virtio_has_dma_quirk(const struct virtio_device *vdev)
212 {
213 /*
214 * Note the reverse polarity of the quirk feature (compared to most
215 * other features), this is for compatibility with legacy systems.
216 */
217 return !virtio_has_feature(vdev, VIRTIO_F_ACCESS_PLATFORM);
218 }
219
220 static inline
221 int virtio_find_vqs(struct virtio_device *vdev, unsigned int nvqs,
222 struct virtqueue *vqs[],
223 struct virtqueue_info vqs_info[],
224 struct irq_affinity *desc)
225 {
226 return vdev->config->find_vqs(vdev, nvqs, vqs, vqs_info, desc);
227 }
228
229 static inline
230 struct virtqueue *virtio_find_single_vq(struct virtio_device *vdev,
231 vq_callback_t *c, const char *n)
232 {
233 struct virtqueue_info vqs_info[] = {
234 { n, c },
235 };
236 struct virtqueue *vq;
237 int err = virtio_find_vqs(vdev, 1, &vq, vqs_info, NULL);
238
239 if (err < 0)
240 return ERR_PTR(err);
241 return vq;
242 }
243
244 /**
245 * virtio_synchronize_cbs - synchronize with virtqueue callbacks
246 * @dev: the virtio device
247 */
248 static inline
249 void virtio_synchronize_cbs(struct virtio_device *dev)
250 {
251 if (dev->config->synchronize_cbs) {
252 dev->config->synchronize_cbs(dev);
253 } else {
254 /*
255 * A best effort fallback to synchronize with
256 * interrupts, preemption and softirq disabled
257 * regions. See comment above synchronize_rcu().
258 */
259 synchronize_rcu();
260 }
261 }
262
263 /**
264 * virtio_device_ready - enable vq use in probe function
265 * @dev: the virtio device
266 *
267 * Driver must call this to use vqs in the probe function.
268 *
269 * Note: vqs are enabled automatically after probe returns.
270 */
271 static inline
272 void virtio_device_ready(struct virtio_device *dev)
273 {
274 unsigned status = dev->config->get_status(dev);
275
276 WARN_ON(status & VIRTIO_CONFIG_S_DRIVER_OK);
277
278 #ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION
279 /*
280 * The virtio_synchronize_cbs() makes sure vring_interrupt()
281 * will see the driver specific setup if it sees vq->broken
282 * as false (even if the notifications come before DRIVER_OK).
283 */
284 virtio_synchronize_cbs(dev);
285 __virtio_unbreak_device(dev);
286 #endif
287 /*
288 * The transport should ensure the visibility of vq->broken
289 * before setting DRIVER_OK. See the comments for the transport
290 * specific set_status() method.
291 *
292 * A well behaved device will only notify a virtqueue after
293 * DRIVER_OK, this means the device should "see" the coherenct
294 * memory write that set vq->broken as false which is done by
295 * the driver when it sees DRIVER_OK, then the following
296 * driver's vring_interrupt() will see vq->broken as false so
297 * we won't lose any notification.
298 */
299 dev->config->set_status(dev, status | VIRTIO_CONFIG_S_DRIVER_OK);
300 }
301
302 static inline
303 const char *virtio_bus_name(struct virtio_device *vdev)
304 {
305 if (!vdev->config->bus_name)
306 return "virtio";
307 return vdev->config->bus_name(vdev);
308 }
309
310 /**
311 * virtqueue_set_affinity - setting affinity for a virtqueue
312 * @vq: the virtqueue
313 * @cpu_mask: the cpu mask
314 *
315 * Pay attention the function are best-effort: the affinity hint may not be set
316 * due to config support, irq type and sharing.
317 *
318 */
319 static inline
320 int virtqueue_set_affinity(struct virtqueue *vq, const struct cpumask *cpu_mask)
321 {
322 struct virtio_device *vdev = vq->vdev;
323 if (vdev->config->set_vq_affinity)
324 return vdev->config->set_vq_affinity(vq, cpu_mask);
325 return 0;
326 }
327
328 static inline
329 bool virtio_get_shm_region(struct virtio_device *vdev,
330 struct virtio_shm_region *region, u8 id)
331 {
332 if (!vdev->config->get_shm_region)
333 return false;
334 return vdev->config->get_shm_region(vdev, region, id);
335 }
336
337 static inline bool virtio_is_little_endian(struct virtio_device *vdev)
338 {
339 return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
340 virtio_legacy_is_little_endian();
341 }
342
343 /* Memory accessors */
344 static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val)
345 {
346 return __virtio16_to_cpu(virtio_is_little_endian(vdev), val);
347 }
348
349 static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val)
350 {
351 return __cpu_to_virtio16(virtio_is_little_endian(vdev), val);
352 }
353
354 static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val)
355 {
356 return __virtio32_to_cpu(virtio_is_little_endian(vdev), val);
357 }
358
359 static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val)
360 {
361 return __cpu_to_virtio32(virtio_is_little_endian(vdev), val);
362 }
363
364 static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val)
365 {
366 return __virtio64_to_cpu(virtio_is_little_endian(vdev), val);
367 }
368
369 static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
370 {
371 return __cpu_to_virtio64(virtio_is_little_endian(vdev), val);
372 }
373
374 #define virtio_to_cpu(vdev, x) \
375 _Generic((x), \
376 __u8: (x), \
377 __virtio16: virtio16_to_cpu((vdev), (x)), \
378 __virtio32: virtio32_to_cpu((vdev), (x)), \
379 __virtio64: virtio64_to_cpu((vdev), (x)) \
380 )
381
382 #define cpu_to_virtio(vdev, x, m) \
383 _Generic((m), \
384 __u8: (x), \
385 __virtio16: cpu_to_virtio16((vdev), (x)), \
386 __virtio32: cpu_to_virtio32((vdev), (x)), \
387 __virtio64: cpu_to_virtio64((vdev), (x)) \
388 )
389
390 #define __virtio_native_type(structname, member) \
391 typeof(virtio_to_cpu(NULL, ((structname*)0)->member))
392
393 /* Config space accessors. */
394 #define virtio_cread(vdev, structname, member, ptr) \
395 do { \
396 typeof(((structname*)0)->member) virtio_cread_v; \
397 \
398 might_sleep(); \
399 /* Sanity check: must match the member's type */ \
400 typecheck(typeof(virtio_to_cpu((vdev), virtio_cread_v)), *(ptr)); \
401 \
402 switch (sizeof(virtio_cread_v)) { \
403 case 1: \
404 case 2: \
405 case 4: \
406 vdev->config->get((vdev), \
407 offsetof(structname, member), \
408 &virtio_cread_v, \
409 sizeof(virtio_cread_v)); \
410 break; \
411 default: \
412 __virtio_cread_many((vdev), \
413 offsetof(structname, member), \
414 &virtio_cread_v, \
415 1, \
416 sizeof(virtio_cread_v)); \
417 break; \
418 } \
419 *(ptr) = virtio_to_cpu(vdev, virtio_cread_v); \
420 } while(0)
421
422 /* Config space accessors. */
423 #define virtio_cwrite(vdev, structname, member, ptr) \
424 do { \
425 typeof(((structname*)0)->member) virtio_cwrite_v = \
426 cpu_to_virtio(vdev, *(ptr), ((structname*)0)->member); \
427 \
428 might_sleep(); \
429 /* Sanity check: must match the member's type */ \
430 typecheck(typeof(virtio_to_cpu((vdev), virtio_cwrite_v)), *(ptr)); \
431 \
432 vdev->config->set((vdev), offsetof(structname, member), \
433 &virtio_cwrite_v, \
434 sizeof(virtio_cwrite_v)); \
435 } while(0)
436
437 /*
438 * Nothing virtio-specific about these, but let's worry about generalizing
439 * these later.
440 */
441 #define virtio_le_to_cpu(x) \
442 _Generic((x), \
443 __u8: (u8)(x), \
444 __le16: (u16)le16_to_cpu(x), \
445 __le32: (u32)le32_to_cpu(x), \
446 __le64: (u64)le64_to_cpu(x) \
447 )
448
449 #define virtio_cpu_to_le(x, m) \
450 _Generic((m), \
451 __u8: (x), \
452 __le16: cpu_to_le16(x), \
453 __le32: cpu_to_le32(x), \
454 __le64: cpu_to_le64(x) \
455 )
456
457 /* LE (e.g. modern) Config space accessors. */
458 #define virtio_cread_le(vdev, structname, member, ptr) \
459 do { \
460 typeof(((structname*)0)->member) virtio_cread_v; \
461 \
462 might_sleep(); \
463 /* Sanity check: must match the member's type */ \
464 typecheck(typeof(virtio_le_to_cpu(virtio_cread_v)), *(ptr)); \
465 \
466 switch (sizeof(virtio_cread_v)) { \
467 case 1: \
468 case 2: \
469 case 4: \
470 vdev->config->get((vdev), \
471 offsetof(structname, member), \
472 &virtio_cread_v, \
473 sizeof(virtio_cread_v)); \
474 break; \
475 default: \
476 __virtio_cread_many((vdev), \
477 offsetof(structname, member), \
478 &virtio_cread_v, \
479 1, \
480 sizeof(virtio_cread_v)); \
481 break; \
482 } \
483 *(ptr) = virtio_le_to_cpu(virtio_cread_v); \
484 } while(0)
485
486 #define virtio_cwrite_le(vdev, structname, member, ptr) \
487 do { \
488 typeof(((structname*)0)->member) virtio_cwrite_v = \
489 virtio_cpu_to_le(*(ptr), ((structname*)0)->member); \
490 \
491 might_sleep(); \
492 /* Sanity check: must match the member's type */ \
493 typecheck(typeof(virtio_le_to_cpu(virtio_cwrite_v)), *(ptr)); \
494 \
495 vdev->config->set((vdev), offsetof(structname, member), \
496 &virtio_cwrite_v, \
497 sizeof(virtio_cwrite_v)); \
498 } while(0)
499
500
501 /* Read @count fields, @bytes each. */
502 static inline void __virtio_cread_many(struct virtio_device *vdev,
503 unsigned int offset,
504 void *buf, size_t count, size_t bytes)
505 {
506 u32 old, gen = vdev->config->generation ?
507 vdev->config->generation(vdev) : 0;
508 int i;
509
510 might_sleep();
511 do {
512 old = gen;
513
514 for (i = 0; i < count; i++)
515 vdev->config->get(vdev, offset + bytes * i,
516 buf + i * bytes, bytes);
517
518 gen = vdev->config->generation ?
519 vdev->config->generation(vdev) : 0;
520 } while (gen != old);
521 }
522
523 static inline void virtio_cread_bytes(struct virtio_device *vdev,
524 unsigned int offset,
525 void *buf, size_t len)
526 {
527 __virtio_cread_many(vdev, offset, buf, len, 1);
528 }
529
530 static inline u8 virtio_cread8(struct virtio_device *vdev, unsigned int offset)
531 {
532 u8 ret;
533
534 might_sleep();
535 vdev->config->get(vdev, offset, &ret, sizeof(ret));
536 return ret;
537 }
538
539 static inline void virtio_cwrite8(struct virtio_device *vdev,
540 unsigned int offset, u8 val)
541 {
542 might_sleep();
543 vdev->config->set(vdev, offset, &val, sizeof(val));
544 }
545
546 static inline u16 virtio_cread16(struct virtio_device *vdev,
547 unsigned int offset)
548 {
549 __virtio16 ret;
550
551 might_sleep();
552 vdev->config->get(vdev, offset, &ret, sizeof(ret));
553 return virtio16_to_cpu(vdev, ret);
554 }
555
556 static inline void virtio_cwrite16(struct virtio_device *vdev,
557 unsigned int offset, u16 val)
558 {
559 __virtio16 v;
560
561 might_sleep();
562 v = cpu_to_virtio16(vdev, val);
563 vdev->config->set(vdev, offset, &v, sizeof(v));
564 }
565
566 static inline u32 virtio_cread32(struct virtio_device *vdev,
567 unsigned int offset)
568 {
569 __virtio32 ret;
570
571 might_sleep();
572 vdev->config->get(vdev, offset, &ret, sizeof(ret));
573 return virtio32_to_cpu(vdev, ret);
574 }
575
576 static inline void virtio_cwrite32(struct virtio_device *vdev,
577 unsigned int offset, u32 val)
578 {
579 __virtio32 v;
580
581 might_sleep();
582 v = cpu_to_virtio32(vdev, val);
583 vdev->config->set(vdev, offset, &v, sizeof(v));
584 }
585
586 static inline u64 virtio_cread64(struct virtio_device *vdev,
587 unsigned int offset)
588 {
589 __virtio64 ret;
590
591 __virtio_cread_many(vdev, offset, &ret, 1, sizeof(ret));
592 return virtio64_to_cpu(vdev, ret);
593 }
594
595 static inline void virtio_cwrite64(struct virtio_device *vdev,
596 unsigned int offset, u64 val)
597 {
598 __virtio64 v;
599
600 might_sleep();
601 v = cpu_to_virtio64(vdev, val);
602 vdev->config->set(vdev, offset, &v, sizeof(v));
603 }
604
605 /* Conditional config space accessors. */
606 #define virtio_cread_feature(vdev, fbit, structname, member, ptr) \
607 ({ \
608 int _r = 0; \
609 if (!virtio_has_feature(vdev, fbit)) \
610 _r = -ENOENT; \
611 else \
612 virtio_cread((vdev), structname, member, ptr); \
613 _r; \
614 })
615
616 /* Conditional config space accessors. */
617 #define virtio_cread_le_feature(vdev, fbit, structname, member, ptr) \
618 ({ \
619 int _r = 0; \
620 if (!virtio_has_feature(vdev, fbit)) \
621 _r = -ENOENT; \
622 else \
623 virtio_cread_le((vdev), structname, member, ptr); \
624 _r; \
625 })
626
627 #endif /* _LINUX_VIRTIO_CONFIG_H */
628
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