Merge remote-tracking branch 'remotes/stefanha/tags/tracing-pull-request' into staging
[qemu.git] / hw / virtio / virtio.c
1 /*
2 * Virtio Support
3 *
4 * Copyright IBM, Corp. 2007
5 *
6 * Authors:
7 * Anthony Liguori <aliguori@us.ibm.com>
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2. See
10 * the COPYING file in the top-level directory.
11 *
12 */
13
14 #include "qemu/osdep.h"
15 #include "qapi/error.h"
16 #include "qemu-common.h"
17 #include "cpu.h"
18 #include "trace.h"
19 #include "exec/address-spaces.h"
20 #include "qemu/error-report.h"
21 #include "hw/virtio/virtio.h"
22 #include "qemu/atomic.h"
23 #include "hw/virtio/virtio-bus.h"
24 #include "migration/migration.h"
25 #include "hw/virtio/virtio-access.h"
26 #include "sysemu/dma.h"
27
28 /*
29 * The alignment to use between consumer and producer parts of vring.
30 * x86 pagesize again. This is the default, used by transports like PCI
31 * which don't provide a means for the guest to tell the host the alignment.
32 */
33 #define VIRTIO_PCI_VRING_ALIGN 4096
34
35 typedef struct VRingDesc
36 {
37 uint64_t addr;
38 uint32_t len;
39 uint16_t flags;
40 uint16_t next;
41 } VRingDesc;
42
43 typedef struct VRingAvail
44 {
45 uint16_t flags;
46 uint16_t idx;
47 uint16_t ring[0];
48 } VRingAvail;
49
50 typedef struct VRingUsedElem
51 {
52 uint32_t id;
53 uint32_t len;
54 } VRingUsedElem;
55
56 typedef struct VRingUsed
57 {
58 uint16_t flags;
59 uint16_t idx;
60 VRingUsedElem ring[0];
61 } VRingUsed;
62
63 typedef struct VRingMemoryRegionCaches {
64 struct rcu_head rcu;
65 MemoryRegionCache desc;
66 MemoryRegionCache avail;
67 MemoryRegionCache used;
68 } VRingMemoryRegionCaches;
69
70 typedef struct VRing
71 {
72 unsigned int num;
73 unsigned int num_default;
74 unsigned int align;
75 hwaddr desc;
76 hwaddr avail;
77 hwaddr used;
78 VRingMemoryRegionCaches *caches;
79 } VRing;
80
81 struct VirtQueue
82 {
83 VRing vring;
84
85 /* Next head to pop */
86 uint16_t last_avail_idx;
87
88 /* Last avail_idx read from VQ. */
89 uint16_t shadow_avail_idx;
90
91 uint16_t used_idx;
92
93 /* Last used index value we have signalled on */
94 uint16_t signalled_used;
95
96 /* Last used index value we have signalled on */
97 bool signalled_used_valid;
98
99 /* Notification enabled? */
100 bool notification;
101
102 uint16_t queue_index;
103
104 unsigned int inuse;
105
106 uint16_t vector;
107 VirtIOHandleOutput handle_output;
108 VirtIOHandleAIOOutput handle_aio_output;
109 VirtIODevice *vdev;
110 EventNotifier guest_notifier;
111 EventNotifier host_notifier;
112 QLIST_ENTRY(VirtQueue) node;
113 };
114
115 static void virtio_free_region_cache(VRingMemoryRegionCaches *caches)
116 {
117 if (!caches) {
118 return;
119 }
120
121 address_space_cache_destroy(&caches->desc);
122 address_space_cache_destroy(&caches->avail);
123 address_space_cache_destroy(&caches->used);
124 g_free(caches);
125 }
126
127 static void virtio_init_region_cache(VirtIODevice *vdev, int n)
128 {
129 VirtQueue *vq = &vdev->vq[n];
130 VRingMemoryRegionCaches *old = vq->vring.caches;
131 VRingMemoryRegionCaches *new;
132 hwaddr addr, size;
133 int event_size;
134 int64_t len;
135
136 event_size = virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
137
138 addr = vq->vring.desc;
139 if (!addr) {
140 return;
141 }
142 new = g_new0(VRingMemoryRegionCaches, 1);
143 size = virtio_queue_get_desc_size(vdev, n);
144 len = address_space_cache_init(&new->desc, vdev->dma_as,
145 addr, size, false);
146 if (len < size) {
147 virtio_error(vdev, "Cannot map desc");
148 goto err_desc;
149 }
150
151 size = virtio_queue_get_used_size(vdev, n) + event_size;
152 len = address_space_cache_init(&new->used, vdev->dma_as,
153 vq->vring.used, size, true);
154 if (len < size) {
155 virtio_error(vdev, "Cannot map used");
156 goto err_used;
157 }
158
159 size = virtio_queue_get_avail_size(vdev, n) + event_size;
160 len = address_space_cache_init(&new->avail, vdev->dma_as,
161 vq->vring.avail, size, false);
162 if (len < size) {
163 virtio_error(vdev, "Cannot map avail");
164 goto err_avail;
165 }
166
167 atomic_rcu_set(&vq->vring.caches, new);
168 if (old) {
169 call_rcu(old, virtio_free_region_cache, rcu);
170 }
171 return;
172
173 err_avail:
174 address_space_cache_destroy(&new->used);
175 err_used:
176 address_space_cache_destroy(&new->desc);
177 err_desc:
178 g_free(new);
179 }
180
181 /* virt queue functions */
182 void virtio_queue_update_rings(VirtIODevice *vdev, int n)
183 {
184 VRing *vring = &vdev->vq[n].vring;
185
186 if (!vring->desc) {
187 /* not yet setup -> nothing to do */
188 return;
189 }
190 vring->avail = vring->desc + vring->num * sizeof(VRingDesc);
191 vring->used = vring_align(vring->avail +
192 offsetof(VRingAvail, ring[vring->num]),
193 vring->align);
194 virtio_init_region_cache(vdev, n);
195 }
196
197 /* Called within rcu_read_lock(). */
198 static void vring_desc_read(VirtIODevice *vdev, VRingDesc *desc,
199 MemoryRegionCache *cache, int i)
200 {
201 address_space_read_cached(cache, i * sizeof(VRingDesc),
202 desc, sizeof(VRingDesc));
203 virtio_tswap64s(vdev, &desc->addr);
204 virtio_tswap32s(vdev, &desc->len);
205 virtio_tswap16s(vdev, &desc->flags);
206 virtio_tswap16s(vdev, &desc->next);
207 }
208
209 static VRingMemoryRegionCaches *vring_get_region_caches(struct VirtQueue *vq)
210 {
211 VRingMemoryRegionCaches *caches = atomic_rcu_read(&vq->vring.caches);
212 assert(caches != NULL);
213 return caches;
214 }
215 /* Called within rcu_read_lock(). */
216 static inline uint16_t vring_avail_flags(VirtQueue *vq)
217 {
218 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
219 hwaddr pa = offsetof(VRingAvail, flags);
220 return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
221 }
222
223 /* Called within rcu_read_lock(). */
224 static inline uint16_t vring_avail_idx(VirtQueue *vq)
225 {
226 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
227 hwaddr pa = offsetof(VRingAvail, idx);
228 vq->shadow_avail_idx = virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
229 return vq->shadow_avail_idx;
230 }
231
232 /* Called within rcu_read_lock(). */
233 static inline uint16_t vring_avail_ring(VirtQueue *vq, int i)
234 {
235 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
236 hwaddr pa = offsetof(VRingAvail, ring[i]);
237 return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
238 }
239
240 /* Called within rcu_read_lock(). */
241 static inline uint16_t vring_get_used_event(VirtQueue *vq)
242 {
243 return vring_avail_ring(vq, vq->vring.num);
244 }
245
246 /* Called within rcu_read_lock(). */
247 static inline void vring_used_write(VirtQueue *vq, VRingUsedElem *uelem,
248 int i)
249 {
250 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
251 hwaddr pa = offsetof(VRingUsed, ring[i]);
252 virtio_tswap32s(vq->vdev, &uelem->id);
253 virtio_tswap32s(vq->vdev, &uelem->len);
254 address_space_write_cached(&caches->used, pa, uelem, sizeof(VRingUsedElem));
255 address_space_cache_invalidate(&caches->used, pa, sizeof(VRingUsedElem));
256 }
257
258 /* Called within rcu_read_lock(). */
259 static uint16_t vring_used_idx(VirtQueue *vq)
260 {
261 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
262 hwaddr pa = offsetof(VRingUsed, idx);
263 return virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
264 }
265
266 /* Called within rcu_read_lock(). */
267 static inline void vring_used_idx_set(VirtQueue *vq, uint16_t val)
268 {
269 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
270 hwaddr pa = offsetof(VRingUsed, idx);
271 virtio_stw_phys_cached(vq->vdev, &caches->used, pa, val);
272 address_space_cache_invalidate(&caches->used, pa, sizeof(val));
273 vq->used_idx = val;
274 }
275
276 /* Called within rcu_read_lock(). */
277 static inline void vring_used_flags_set_bit(VirtQueue *vq, int mask)
278 {
279 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
280 VirtIODevice *vdev = vq->vdev;
281 hwaddr pa = offsetof(VRingUsed, flags);
282 uint16_t flags = virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
283
284 virtio_stw_phys_cached(vdev, &caches->used, pa, flags | mask);
285 address_space_cache_invalidate(&caches->used, pa, sizeof(flags));
286 }
287
288 /* Called within rcu_read_lock(). */
289 static inline void vring_used_flags_unset_bit(VirtQueue *vq, int mask)
290 {
291 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
292 VirtIODevice *vdev = vq->vdev;
293 hwaddr pa = offsetof(VRingUsed, flags);
294 uint16_t flags = virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
295
296 virtio_stw_phys_cached(vdev, &caches->used, pa, flags & ~mask);
297 address_space_cache_invalidate(&caches->used, pa, sizeof(flags));
298 }
299
300 /* Called within rcu_read_lock(). */
301 static inline void vring_set_avail_event(VirtQueue *vq, uint16_t val)
302 {
303 VRingMemoryRegionCaches *caches;
304 hwaddr pa;
305 if (!vq->notification) {
306 return;
307 }
308
309 caches = vring_get_region_caches(vq);
310 pa = offsetof(VRingUsed, ring[vq->vring.num]);
311 virtio_stw_phys_cached(vq->vdev, &caches->used, pa, val);
312 address_space_cache_invalidate(&caches->used, pa, sizeof(val));
313 }
314
315 void virtio_queue_set_notification(VirtQueue *vq, int enable)
316 {
317 vq->notification = enable;
318
319 if (!vq->vring.desc) {
320 return;
321 }
322
323 rcu_read_lock();
324 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
325 vring_set_avail_event(vq, vring_avail_idx(vq));
326 } else if (enable) {
327 vring_used_flags_unset_bit(vq, VRING_USED_F_NO_NOTIFY);
328 } else {
329 vring_used_flags_set_bit(vq, VRING_USED_F_NO_NOTIFY);
330 }
331 if (enable) {
332 /* Expose avail event/used flags before caller checks the avail idx. */
333 smp_mb();
334 }
335 rcu_read_unlock();
336 }
337
338 int virtio_queue_ready(VirtQueue *vq)
339 {
340 return vq->vring.avail != 0;
341 }
342
343 /* Fetch avail_idx from VQ memory only when we really need to know if
344 * guest has added some buffers.
345 * Called within rcu_read_lock(). */
346 static int virtio_queue_empty_rcu(VirtQueue *vq)
347 {
348 if (unlikely(!vq->vring.avail)) {
349 return 1;
350 }
351
352 if (vq->shadow_avail_idx != vq->last_avail_idx) {
353 return 0;
354 }
355
356 return vring_avail_idx(vq) == vq->last_avail_idx;
357 }
358
359 int virtio_queue_empty(VirtQueue *vq)
360 {
361 bool empty;
362
363 if (unlikely(!vq->vring.avail)) {
364 return 1;
365 }
366
367 if (vq->shadow_avail_idx != vq->last_avail_idx) {
368 return 0;
369 }
370
371 rcu_read_lock();
372 empty = vring_avail_idx(vq) == vq->last_avail_idx;
373 rcu_read_unlock();
374 return empty;
375 }
376
377 static void virtqueue_unmap_sg(VirtQueue *vq, const VirtQueueElement *elem,
378 unsigned int len)
379 {
380 AddressSpace *dma_as = vq->vdev->dma_as;
381 unsigned int offset;
382 int i;
383
384 offset = 0;
385 for (i = 0; i < elem->in_num; i++) {
386 size_t size = MIN(len - offset, elem->in_sg[i].iov_len);
387
388 dma_memory_unmap(dma_as, elem->in_sg[i].iov_base,
389 elem->in_sg[i].iov_len,
390 DMA_DIRECTION_FROM_DEVICE, size);
391
392 offset += size;
393 }
394
395 for (i = 0; i < elem->out_num; i++)
396 dma_memory_unmap(dma_as, elem->out_sg[i].iov_base,
397 elem->out_sg[i].iov_len,
398 DMA_DIRECTION_TO_DEVICE,
399 elem->out_sg[i].iov_len);
400 }
401
402 /* virtqueue_detach_element:
403 * @vq: The #VirtQueue
404 * @elem: The #VirtQueueElement
405 * @len: number of bytes written
406 *
407 * Detach the element from the virtqueue. This function is suitable for device
408 * reset or other situations where a #VirtQueueElement is simply freed and will
409 * not be pushed or discarded.
410 */
411 void virtqueue_detach_element(VirtQueue *vq, const VirtQueueElement *elem,
412 unsigned int len)
413 {
414 vq->inuse--;
415 virtqueue_unmap_sg(vq, elem, len);
416 }
417
418 /* virtqueue_unpop:
419 * @vq: The #VirtQueue
420 * @elem: The #VirtQueueElement
421 * @len: number of bytes written
422 *
423 * Pretend the most recent element wasn't popped from the virtqueue. The next
424 * call to virtqueue_pop() will refetch the element.
425 */
426 void virtqueue_unpop(VirtQueue *vq, const VirtQueueElement *elem,
427 unsigned int len)
428 {
429 vq->last_avail_idx--;
430 virtqueue_detach_element(vq, elem, len);
431 }
432
433 /* virtqueue_rewind:
434 * @vq: The #VirtQueue
435 * @num: Number of elements to push back
436 *
437 * Pretend that elements weren't popped from the virtqueue. The next
438 * virtqueue_pop() will refetch the oldest element.
439 *
440 * Use virtqueue_unpop() instead if you have a VirtQueueElement.
441 *
442 * Returns: true on success, false if @num is greater than the number of in use
443 * elements.
444 */
445 bool virtqueue_rewind(VirtQueue *vq, unsigned int num)
446 {
447 if (num > vq->inuse) {
448 return false;
449 }
450 vq->last_avail_idx -= num;
451 vq->inuse -= num;
452 return true;
453 }
454
455 /* Called within rcu_read_lock(). */
456 void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
457 unsigned int len, unsigned int idx)
458 {
459 VRingUsedElem uelem;
460
461 trace_virtqueue_fill(vq, elem, len, idx);
462
463 virtqueue_unmap_sg(vq, elem, len);
464
465 if (unlikely(vq->vdev->broken)) {
466 return;
467 }
468
469 if (unlikely(!vq->vring.used)) {
470 return;
471 }
472
473 idx = (idx + vq->used_idx) % vq->vring.num;
474
475 uelem.id = elem->index;
476 uelem.len = len;
477 vring_used_write(vq, &uelem, idx);
478 }
479
480 /* Called within rcu_read_lock(). */
481 void virtqueue_flush(VirtQueue *vq, unsigned int count)
482 {
483 uint16_t old, new;
484
485 if (unlikely(vq->vdev->broken)) {
486 vq->inuse -= count;
487 return;
488 }
489
490 if (unlikely(!vq->vring.used)) {
491 return;
492 }
493
494 /* Make sure buffer is written before we update index. */
495 smp_wmb();
496 trace_virtqueue_flush(vq, count);
497 old = vq->used_idx;
498 new = old + count;
499 vring_used_idx_set(vq, new);
500 vq->inuse -= count;
501 if (unlikely((int16_t)(new - vq->signalled_used) < (uint16_t)(new - old)))
502 vq->signalled_used_valid = false;
503 }
504
505 void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
506 unsigned int len)
507 {
508 rcu_read_lock();
509 virtqueue_fill(vq, elem, len, 0);
510 virtqueue_flush(vq, 1);
511 rcu_read_unlock();
512 }
513
514 /* Called within rcu_read_lock(). */
515 static int virtqueue_num_heads(VirtQueue *vq, unsigned int idx)
516 {
517 uint16_t num_heads = vring_avail_idx(vq) - idx;
518
519 /* Check it isn't doing very strange things with descriptor numbers. */
520 if (num_heads > vq->vring.num) {
521 virtio_error(vq->vdev, "Guest moved used index from %u to %u",
522 idx, vq->shadow_avail_idx);
523 return -EINVAL;
524 }
525 /* On success, callers read a descriptor at vq->last_avail_idx.
526 * Make sure descriptor read does not bypass avail index read. */
527 if (num_heads) {
528 smp_rmb();
529 }
530
531 return num_heads;
532 }
533
534 /* Called within rcu_read_lock(). */
535 static bool virtqueue_get_head(VirtQueue *vq, unsigned int idx,
536 unsigned int *head)
537 {
538 /* Grab the next descriptor number they're advertising, and increment
539 * the index we've seen. */
540 *head = vring_avail_ring(vq, idx % vq->vring.num);
541
542 /* If their number is silly, that's a fatal mistake. */
543 if (*head >= vq->vring.num) {
544 virtio_error(vq->vdev, "Guest says index %u is available", *head);
545 return false;
546 }
547
548 return true;
549 }
550
551 enum {
552 VIRTQUEUE_READ_DESC_ERROR = -1,
553 VIRTQUEUE_READ_DESC_DONE = 0, /* end of chain */
554 VIRTQUEUE_READ_DESC_MORE = 1, /* more buffers in chain */
555 };
556
557 static int virtqueue_read_next_desc(VirtIODevice *vdev, VRingDesc *desc,
558 MemoryRegionCache *desc_cache, unsigned int max,
559 unsigned int *next)
560 {
561 /* If this descriptor says it doesn't chain, we're done. */
562 if (!(desc->flags & VRING_DESC_F_NEXT)) {
563 return VIRTQUEUE_READ_DESC_DONE;
564 }
565
566 /* Check they're not leading us off end of descriptors. */
567 *next = desc->next;
568 /* Make sure compiler knows to grab that: we don't want it changing! */
569 smp_wmb();
570
571 if (*next >= max) {
572 virtio_error(vdev, "Desc next is %u", *next);
573 return VIRTQUEUE_READ_DESC_ERROR;
574 }
575
576 vring_desc_read(vdev, desc, desc_cache, *next);
577 return VIRTQUEUE_READ_DESC_MORE;
578 }
579
580 void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
581 unsigned int *out_bytes,
582 unsigned max_in_bytes, unsigned max_out_bytes)
583 {
584 VirtIODevice *vdev = vq->vdev;
585 unsigned int max, idx;
586 unsigned int total_bufs, in_total, out_total;
587 VRingMemoryRegionCaches *caches;
588 MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
589 int64_t len = 0;
590 int rc;
591
592 if (unlikely(!vq->vring.desc)) {
593 if (in_bytes) {
594 *in_bytes = 0;
595 }
596 if (out_bytes) {
597 *out_bytes = 0;
598 }
599 return;
600 }
601
602 rcu_read_lock();
603 idx = vq->last_avail_idx;
604 total_bufs = in_total = out_total = 0;
605
606 max = vq->vring.num;
607 caches = vring_get_region_caches(vq);
608 if (caches->desc.len < max * sizeof(VRingDesc)) {
609 virtio_error(vdev, "Cannot map descriptor ring");
610 goto err;
611 }
612
613 while ((rc = virtqueue_num_heads(vq, idx)) > 0) {
614 MemoryRegionCache *desc_cache = &caches->desc;
615 unsigned int num_bufs;
616 VRingDesc desc;
617 unsigned int i;
618
619 num_bufs = total_bufs;
620
621 if (!virtqueue_get_head(vq, idx++, &i)) {
622 goto err;
623 }
624
625 vring_desc_read(vdev, &desc, desc_cache, i);
626
627 if (desc.flags & VRING_DESC_F_INDIRECT) {
628 if (desc.len % sizeof(VRingDesc)) {
629 virtio_error(vdev, "Invalid size for indirect buffer table");
630 goto err;
631 }
632
633 /* If we've got too many, that implies a descriptor loop. */
634 if (num_bufs >= max) {
635 virtio_error(vdev, "Looped descriptor");
636 goto err;
637 }
638
639 /* loop over the indirect descriptor table */
640 len = address_space_cache_init(&indirect_desc_cache,
641 vdev->dma_as,
642 desc.addr, desc.len, false);
643 desc_cache = &indirect_desc_cache;
644 if (len < desc.len) {
645 virtio_error(vdev, "Cannot map indirect buffer");
646 goto err;
647 }
648
649 max = desc.len / sizeof(VRingDesc);
650 num_bufs = i = 0;
651 vring_desc_read(vdev, &desc, desc_cache, i);
652 }
653
654 do {
655 /* If we've got too many, that implies a descriptor loop. */
656 if (++num_bufs > max) {
657 virtio_error(vdev, "Looped descriptor");
658 goto err;
659 }
660
661 if (desc.flags & VRING_DESC_F_WRITE) {
662 in_total += desc.len;
663 } else {
664 out_total += desc.len;
665 }
666 if (in_total >= max_in_bytes && out_total >= max_out_bytes) {
667 goto done;
668 }
669
670 rc = virtqueue_read_next_desc(vdev, &desc, desc_cache, max, &i);
671 } while (rc == VIRTQUEUE_READ_DESC_MORE);
672
673 if (rc == VIRTQUEUE_READ_DESC_ERROR) {
674 goto err;
675 }
676
677 if (desc_cache == &indirect_desc_cache) {
678 address_space_cache_destroy(&indirect_desc_cache);
679 total_bufs++;
680 } else {
681 total_bufs = num_bufs;
682 }
683 }
684
685 if (rc < 0) {
686 goto err;
687 }
688
689 done:
690 address_space_cache_destroy(&indirect_desc_cache);
691 if (in_bytes) {
692 *in_bytes = in_total;
693 }
694 if (out_bytes) {
695 *out_bytes = out_total;
696 }
697 rcu_read_unlock();
698 return;
699
700 err:
701 in_total = out_total = 0;
702 goto done;
703 }
704
705 int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes,
706 unsigned int out_bytes)
707 {
708 unsigned int in_total, out_total;
709
710 virtqueue_get_avail_bytes(vq, &in_total, &out_total, in_bytes, out_bytes);
711 return in_bytes <= in_total && out_bytes <= out_total;
712 }
713
714 static bool virtqueue_map_desc(VirtIODevice *vdev, unsigned int *p_num_sg,
715 hwaddr *addr, struct iovec *iov,
716 unsigned int max_num_sg, bool is_write,
717 hwaddr pa, size_t sz)
718 {
719 bool ok = false;
720 unsigned num_sg = *p_num_sg;
721 assert(num_sg <= max_num_sg);
722
723 if (!sz) {
724 virtio_error(vdev, "virtio: zero sized buffers are not allowed");
725 goto out;
726 }
727
728 while (sz) {
729 hwaddr len = sz;
730
731 if (num_sg == max_num_sg) {
732 virtio_error(vdev, "virtio: too many write descriptors in "
733 "indirect table");
734 goto out;
735 }
736
737 iov[num_sg].iov_base = dma_memory_map(vdev->dma_as, pa, &len,
738 is_write ?
739 DMA_DIRECTION_FROM_DEVICE :
740 DMA_DIRECTION_TO_DEVICE);
741 if (!iov[num_sg].iov_base) {
742 virtio_error(vdev, "virtio: bogus descriptor or out of resources");
743 goto out;
744 }
745
746 iov[num_sg].iov_len = len;
747 addr[num_sg] = pa;
748
749 sz -= len;
750 pa += len;
751 num_sg++;
752 }
753 ok = true;
754
755 out:
756 *p_num_sg = num_sg;
757 return ok;
758 }
759
760 /* Only used by error code paths before we have a VirtQueueElement (therefore
761 * virtqueue_unmap_sg() can't be used). Assumes buffers weren't written to
762 * yet.
763 */
764 static void virtqueue_undo_map_desc(unsigned int out_num, unsigned int in_num,
765 struct iovec *iov)
766 {
767 unsigned int i;
768
769 for (i = 0; i < out_num + in_num; i++) {
770 int is_write = i >= out_num;
771
772 cpu_physical_memory_unmap(iov->iov_base, iov->iov_len, is_write, 0);
773 iov++;
774 }
775 }
776
777 static void virtqueue_map_iovec(VirtIODevice *vdev, struct iovec *sg,
778 hwaddr *addr, unsigned int *num_sg,
779 int is_write)
780 {
781 unsigned int i;
782 hwaddr len;
783
784 for (i = 0; i < *num_sg; i++) {
785 len = sg[i].iov_len;
786 sg[i].iov_base = dma_memory_map(vdev->dma_as,
787 addr[i], &len, is_write ?
788 DMA_DIRECTION_FROM_DEVICE :
789 DMA_DIRECTION_TO_DEVICE);
790 if (!sg[i].iov_base) {
791 error_report("virtio: error trying to map MMIO memory");
792 exit(1);
793 }
794 if (len != sg[i].iov_len) {
795 error_report("virtio: unexpected memory split");
796 exit(1);
797 }
798 }
799 }
800
801 void virtqueue_map(VirtIODevice *vdev, VirtQueueElement *elem)
802 {
803 virtqueue_map_iovec(vdev, elem->in_sg, elem->in_addr, &elem->in_num, 1);
804 virtqueue_map_iovec(vdev, elem->out_sg, elem->out_addr, &elem->out_num, 0);
805 }
806
807 static void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned in_num)
808 {
809 VirtQueueElement *elem;
810 size_t in_addr_ofs = QEMU_ALIGN_UP(sz, __alignof__(elem->in_addr[0]));
811 size_t out_addr_ofs = in_addr_ofs + in_num * sizeof(elem->in_addr[0]);
812 size_t out_addr_end = out_addr_ofs + out_num * sizeof(elem->out_addr[0]);
813 size_t in_sg_ofs = QEMU_ALIGN_UP(out_addr_end, __alignof__(elem->in_sg[0]));
814 size_t out_sg_ofs = in_sg_ofs + in_num * sizeof(elem->in_sg[0]);
815 size_t out_sg_end = out_sg_ofs + out_num * sizeof(elem->out_sg[0]);
816
817 assert(sz >= sizeof(VirtQueueElement));
818 elem = g_malloc(out_sg_end);
819 elem->out_num = out_num;
820 elem->in_num = in_num;
821 elem->in_addr = (void *)elem + in_addr_ofs;
822 elem->out_addr = (void *)elem + out_addr_ofs;
823 elem->in_sg = (void *)elem + in_sg_ofs;
824 elem->out_sg = (void *)elem + out_sg_ofs;
825 return elem;
826 }
827
828 void *virtqueue_pop(VirtQueue *vq, size_t sz)
829 {
830 unsigned int i, head, max;
831 VRingMemoryRegionCaches *caches;
832 MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
833 MemoryRegionCache *desc_cache;
834 int64_t len;
835 VirtIODevice *vdev = vq->vdev;
836 VirtQueueElement *elem = NULL;
837 unsigned out_num, in_num;
838 hwaddr addr[VIRTQUEUE_MAX_SIZE];
839 struct iovec iov[VIRTQUEUE_MAX_SIZE];
840 VRingDesc desc;
841 int rc;
842
843 if (unlikely(vdev->broken)) {
844 return NULL;
845 }
846 rcu_read_lock();
847 if (virtio_queue_empty_rcu(vq)) {
848 goto done;
849 }
850 /* Needed after virtio_queue_empty(), see comment in
851 * virtqueue_num_heads(). */
852 smp_rmb();
853
854 /* When we start there are none of either input nor output. */
855 out_num = in_num = 0;
856
857 max = vq->vring.num;
858
859 if (vq->inuse >= vq->vring.num) {
860 virtio_error(vdev, "Virtqueue size exceeded");
861 goto done;
862 }
863
864 if (!virtqueue_get_head(vq, vq->last_avail_idx++, &head)) {
865 goto done;
866 }
867
868 if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
869 vring_set_avail_event(vq, vq->last_avail_idx);
870 }
871
872 i = head;
873
874 caches = vring_get_region_caches(vq);
875 if (caches->desc.len < max * sizeof(VRingDesc)) {
876 virtio_error(vdev, "Cannot map descriptor ring");
877 goto done;
878 }
879
880 desc_cache = &caches->desc;
881 vring_desc_read(vdev, &desc, desc_cache, i);
882 if (desc.flags & VRING_DESC_F_INDIRECT) {
883 if (desc.len % sizeof(VRingDesc)) {
884 virtio_error(vdev, "Invalid size for indirect buffer table");
885 goto done;
886 }
887
888 /* loop over the indirect descriptor table */
889 len = address_space_cache_init(&indirect_desc_cache, vdev->dma_as,
890 desc.addr, desc.len, false);
891 desc_cache = &indirect_desc_cache;
892 if (len < desc.len) {
893 virtio_error(vdev, "Cannot map indirect buffer");
894 goto done;
895 }
896
897 max = desc.len / sizeof(VRingDesc);
898 i = 0;
899 vring_desc_read(vdev, &desc, desc_cache, i);
900 }
901
902 /* Collect all the descriptors */
903 do {
904 bool map_ok;
905
906 if (desc.flags & VRING_DESC_F_WRITE) {
907 map_ok = virtqueue_map_desc(vdev, &in_num, addr + out_num,
908 iov + out_num,
909 VIRTQUEUE_MAX_SIZE - out_num, true,
910 desc.addr, desc.len);
911 } else {
912 if (in_num) {
913 virtio_error(vdev, "Incorrect order for descriptors");
914 goto err_undo_map;
915 }
916 map_ok = virtqueue_map_desc(vdev, &out_num, addr, iov,
917 VIRTQUEUE_MAX_SIZE, false,
918 desc.addr, desc.len);
919 }
920 if (!map_ok) {
921 goto err_undo_map;
922 }
923
924 /* If we've got too many, that implies a descriptor loop. */
925 if ((in_num + out_num) > max) {
926 virtio_error(vdev, "Looped descriptor");
927 goto err_undo_map;
928 }
929
930 rc = virtqueue_read_next_desc(vdev, &desc, desc_cache, max, &i);
931 } while (rc == VIRTQUEUE_READ_DESC_MORE);
932
933 if (rc == VIRTQUEUE_READ_DESC_ERROR) {
934 goto err_undo_map;
935 }
936
937 /* Now copy what we have collected and mapped */
938 elem = virtqueue_alloc_element(sz, out_num, in_num);
939 elem->index = head;
940 for (i = 0; i < out_num; i++) {
941 elem->out_addr[i] = addr[i];
942 elem->out_sg[i] = iov[i];
943 }
944 for (i = 0; i < in_num; i++) {
945 elem->in_addr[i] = addr[out_num + i];
946 elem->in_sg[i] = iov[out_num + i];
947 }
948
949 vq->inuse++;
950
951 trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num);
952 done:
953 address_space_cache_destroy(&indirect_desc_cache);
954 rcu_read_unlock();
955
956 return elem;
957
958 err_undo_map:
959 virtqueue_undo_map_desc(out_num, in_num, iov);
960 goto done;
961 }
962
963 /* virtqueue_drop_all:
964 * @vq: The #VirtQueue
965 * Drops all queued buffers and indicates them to the guest
966 * as if they are done. Useful when buffers can not be
967 * processed but must be returned to the guest.
968 */
969 unsigned int virtqueue_drop_all(VirtQueue *vq)
970 {
971 unsigned int dropped = 0;
972 VirtQueueElement elem = {};
973 VirtIODevice *vdev = vq->vdev;
974 bool fEventIdx = virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
975
976 if (unlikely(vdev->broken)) {
977 return 0;
978 }
979
980 while (!virtio_queue_empty(vq) && vq->inuse < vq->vring.num) {
981 /* works similar to virtqueue_pop but does not map buffers
982 * and does not allocate any memory */
983 smp_rmb();
984 if (!virtqueue_get_head(vq, vq->last_avail_idx, &elem.index)) {
985 break;
986 }
987 vq->inuse++;
988 vq->last_avail_idx++;
989 if (fEventIdx) {
990 vring_set_avail_event(vq, vq->last_avail_idx);
991 }
992 /* immediately push the element, nothing to unmap
993 * as both in_num and out_num are set to 0 */
994 virtqueue_push(vq, &elem, 0);
995 dropped++;
996 }
997
998 return dropped;
999 }
1000
1001 /* Reading and writing a structure directly to QEMUFile is *awful*, but
1002 * it is what QEMU has always done by mistake. We can change it sooner
1003 * or later by bumping the version number of the affected vm states.
1004 * In the meanwhile, since the in-memory layout of VirtQueueElement
1005 * has changed, we need to marshal to and from the layout that was
1006 * used before the change.
1007 */
1008 typedef struct VirtQueueElementOld {
1009 unsigned int index;
1010 unsigned int out_num;
1011 unsigned int in_num;
1012 hwaddr in_addr[VIRTQUEUE_MAX_SIZE];
1013 hwaddr out_addr[VIRTQUEUE_MAX_SIZE];
1014 struct iovec in_sg[VIRTQUEUE_MAX_SIZE];
1015 struct iovec out_sg[VIRTQUEUE_MAX_SIZE];
1016 } VirtQueueElementOld;
1017
1018 void *qemu_get_virtqueue_element(VirtIODevice *vdev, QEMUFile *f, size_t sz)
1019 {
1020 VirtQueueElement *elem;
1021 VirtQueueElementOld data;
1022 int i;
1023
1024 qemu_get_buffer(f, (uint8_t *)&data, sizeof(VirtQueueElementOld));
1025
1026 /* TODO: teach all callers that this can fail, and return failure instead
1027 * of asserting here.
1028 * When we do, we might be able to re-enable NDEBUG below.
1029 */
1030 #ifdef NDEBUG
1031 #error building with NDEBUG is not supported
1032 #endif
1033 assert(ARRAY_SIZE(data.in_addr) >= data.in_num);
1034 assert(ARRAY_SIZE(data.out_addr) >= data.out_num);
1035
1036 elem = virtqueue_alloc_element(sz, data.out_num, data.in_num);
1037 elem->index = data.index;
1038
1039 for (i = 0; i < elem->in_num; i++) {
1040 elem->in_addr[i] = data.in_addr[i];
1041 }
1042
1043 for (i = 0; i < elem->out_num; i++) {
1044 elem->out_addr[i] = data.out_addr[i];
1045 }
1046
1047 for (i = 0; i < elem->in_num; i++) {
1048 /* Base is overwritten by virtqueue_map. */
1049 elem->in_sg[i].iov_base = 0;
1050 elem->in_sg[i].iov_len = data.in_sg[i].iov_len;
1051 }
1052
1053 for (i = 0; i < elem->out_num; i++) {
1054 /* Base is overwritten by virtqueue_map. */
1055 elem->out_sg[i].iov_base = 0;
1056 elem->out_sg[i].iov_len = data.out_sg[i].iov_len;
1057 }
1058
1059 virtqueue_map(vdev, elem);
1060 return elem;
1061 }
1062
1063 void qemu_put_virtqueue_element(QEMUFile *f, VirtQueueElement *elem)
1064 {
1065 VirtQueueElementOld data;
1066 int i;
1067
1068 memset(&data, 0, sizeof(data));
1069 data.index = elem->index;
1070 data.in_num = elem->in_num;
1071 data.out_num = elem->out_num;
1072
1073 for (i = 0; i < elem->in_num; i++) {
1074 data.in_addr[i] = elem->in_addr[i];
1075 }
1076
1077 for (i = 0; i < elem->out_num; i++) {
1078 data.out_addr[i] = elem->out_addr[i];
1079 }
1080
1081 for (i = 0; i < elem->in_num; i++) {
1082 /* Base is overwritten by virtqueue_map when loading. Do not
1083 * save it, as it would leak the QEMU address space layout. */
1084 data.in_sg[i].iov_len = elem->in_sg[i].iov_len;
1085 }
1086
1087 for (i = 0; i < elem->out_num; i++) {
1088 /* Do not save iov_base as above. */
1089 data.out_sg[i].iov_len = elem->out_sg[i].iov_len;
1090 }
1091 qemu_put_buffer(f, (uint8_t *)&data, sizeof(VirtQueueElementOld));
1092 }
1093
1094 /* virtio device */
1095 static void virtio_notify_vector(VirtIODevice *vdev, uint16_t vector)
1096 {
1097 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1098 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1099
1100 if (unlikely(vdev->broken)) {
1101 return;
1102 }
1103
1104 if (k->notify) {
1105 k->notify(qbus->parent, vector);
1106 }
1107 }
1108
1109 void virtio_update_irq(VirtIODevice *vdev)
1110 {
1111 virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
1112 }
1113
1114 static int virtio_validate_features(VirtIODevice *vdev)
1115 {
1116 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1117
1118 if (virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM) &&
1119 !virtio_vdev_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM)) {
1120 return -EFAULT;
1121 }
1122
1123 if (k->validate_features) {
1124 return k->validate_features(vdev);
1125 } else {
1126 return 0;
1127 }
1128 }
1129
1130 int virtio_set_status(VirtIODevice *vdev, uint8_t val)
1131 {
1132 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1133 trace_virtio_set_status(vdev, val);
1134
1135 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
1136 if (!(vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) &&
1137 val & VIRTIO_CONFIG_S_FEATURES_OK) {
1138 int ret = virtio_validate_features(vdev);
1139
1140 if (ret) {
1141 return ret;
1142 }
1143 }
1144 }
1145 if (k->set_status) {
1146 k->set_status(vdev, val);
1147 }
1148 vdev->status = val;
1149 return 0;
1150 }
1151
1152 bool target_words_bigendian(void);
1153 static enum virtio_device_endian virtio_default_endian(void)
1154 {
1155 if (target_words_bigendian()) {
1156 return VIRTIO_DEVICE_ENDIAN_BIG;
1157 } else {
1158 return VIRTIO_DEVICE_ENDIAN_LITTLE;
1159 }
1160 }
1161
1162 static enum virtio_device_endian virtio_current_cpu_endian(void)
1163 {
1164 CPUClass *cc = CPU_GET_CLASS(current_cpu);
1165
1166 if (cc->virtio_is_big_endian(current_cpu)) {
1167 return VIRTIO_DEVICE_ENDIAN_BIG;
1168 } else {
1169 return VIRTIO_DEVICE_ENDIAN_LITTLE;
1170 }
1171 }
1172
1173 static void virtio_virtqueue_reset_region_cache(struct VirtQueue *vq)
1174 {
1175 VRingMemoryRegionCaches *caches;
1176
1177 caches = atomic_read(&vq->vring.caches);
1178 atomic_rcu_set(&vq->vring.caches, NULL);
1179 if (caches) {
1180 call_rcu(caches, virtio_free_region_cache, rcu);
1181 }
1182 }
1183
1184 void virtio_reset(void *opaque)
1185 {
1186 VirtIODevice *vdev = opaque;
1187 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1188 int i;
1189
1190 virtio_set_status(vdev, 0);
1191 if (current_cpu) {
1192 /* Guest initiated reset */
1193 vdev->device_endian = virtio_current_cpu_endian();
1194 } else {
1195 /* System reset */
1196 vdev->device_endian = virtio_default_endian();
1197 }
1198
1199 if (k->reset) {
1200 k->reset(vdev);
1201 }
1202
1203 vdev->broken = false;
1204 vdev->guest_features = 0;
1205 vdev->queue_sel = 0;
1206 vdev->status = 0;
1207 atomic_set(&vdev->isr, 0);
1208 vdev->config_vector = VIRTIO_NO_VECTOR;
1209 virtio_notify_vector(vdev, vdev->config_vector);
1210
1211 for(i = 0; i < VIRTIO_QUEUE_MAX; i++) {
1212 vdev->vq[i].vring.desc = 0;
1213 vdev->vq[i].vring.avail = 0;
1214 vdev->vq[i].vring.used = 0;
1215 vdev->vq[i].last_avail_idx = 0;
1216 vdev->vq[i].shadow_avail_idx = 0;
1217 vdev->vq[i].used_idx = 0;
1218 virtio_queue_set_vector(vdev, i, VIRTIO_NO_VECTOR);
1219 vdev->vq[i].signalled_used = 0;
1220 vdev->vq[i].signalled_used_valid = false;
1221 vdev->vq[i].notification = true;
1222 vdev->vq[i].vring.num = vdev->vq[i].vring.num_default;
1223 vdev->vq[i].inuse = 0;
1224 virtio_virtqueue_reset_region_cache(&vdev->vq[i]);
1225 }
1226 }
1227
1228 uint32_t virtio_config_readb(VirtIODevice *vdev, uint32_t addr)
1229 {
1230 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1231 uint8_t val;
1232
1233 if (addr + sizeof(val) > vdev->config_len) {
1234 return (uint32_t)-1;
1235 }
1236
1237 k->get_config(vdev, vdev->config);
1238
1239 val = ldub_p(vdev->config + addr);
1240 return val;
1241 }
1242
1243 uint32_t virtio_config_readw(VirtIODevice *vdev, uint32_t addr)
1244 {
1245 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1246 uint16_t val;
1247
1248 if (addr + sizeof(val) > vdev->config_len) {
1249 return (uint32_t)-1;
1250 }
1251
1252 k->get_config(vdev, vdev->config);
1253
1254 val = lduw_p(vdev->config + addr);
1255 return val;
1256 }
1257
1258 uint32_t virtio_config_readl(VirtIODevice *vdev, uint32_t addr)
1259 {
1260 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1261 uint32_t val;
1262
1263 if (addr + sizeof(val) > vdev->config_len) {
1264 return (uint32_t)-1;
1265 }
1266
1267 k->get_config(vdev, vdev->config);
1268
1269 val = ldl_p(vdev->config + addr);
1270 return val;
1271 }
1272
1273 void virtio_config_writeb(VirtIODevice *vdev, uint32_t addr, uint32_t data)
1274 {
1275 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1276 uint8_t val = data;
1277
1278 if (addr + sizeof(val) > vdev->config_len) {
1279 return;
1280 }
1281
1282 stb_p(vdev->config + addr, val);
1283
1284 if (k->set_config) {
1285 k->set_config(vdev, vdev->config);
1286 }
1287 }
1288
1289 void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data)
1290 {
1291 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1292 uint16_t val = data;
1293
1294 if (addr + sizeof(val) > vdev->config_len) {
1295 return;
1296 }
1297
1298 stw_p(vdev->config + addr, val);
1299
1300 if (k->set_config) {
1301 k->set_config(vdev, vdev->config);
1302 }
1303 }
1304
1305 void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data)
1306 {
1307 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1308 uint32_t val = data;
1309
1310 if (addr + sizeof(val) > vdev->config_len) {
1311 return;
1312 }
1313
1314 stl_p(vdev->config + addr, val);
1315
1316 if (k->set_config) {
1317 k->set_config(vdev, vdev->config);
1318 }
1319 }
1320
1321 uint32_t virtio_config_modern_readb(VirtIODevice *vdev, uint32_t addr)
1322 {
1323 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1324 uint8_t val;
1325
1326 if (addr + sizeof(val) > vdev->config_len) {
1327 return (uint32_t)-1;
1328 }
1329
1330 k->get_config(vdev, vdev->config);
1331
1332 val = ldub_p(vdev->config + addr);
1333 return val;
1334 }
1335
1336 uint32_t virtio_config_modern_readw(VirtIODevice *vdev, uint32_t addr)
1337 {
1338 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1339 uint16_t val;
1340
1341 if (addr + sizeof(val) > vdev->config_len) {
1342 return (uint32_t)-1;
1343 }
1344
1345 k->get_config(vdev, vdev->config);
1346
1347 val = lduw_le_p(vdev->config + addr);
1348 return val;
1349 }
1350
1351 uint32_t virtio_config_modern_readl(VirtIODevice *vdev, uint32_t addr)
1352 {
1353 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1354 uint32_t val;
1355
1356 if (addr + sizeof(val) > vdev->config_len) {
1357 return (uint32_t)-1;
1358 }
1359
1360 k->get_config(vdev, vdev->config);
1361
1362 val = ldl_le_p(vdev->config + addr);
1363 return val;
1364 }
1365
1366 void virtio_config_modern_writeb(VirtIODevice *vdev,
1367 uint32_t addr, uint32_t data)
1368 {
1369 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1370 uint8_t val = data;
1371
1372 if (addr + sizeof(val) > vdev->config_len) {
1373 return;
1374 }
1375
1376 stb_p(vdev->config + addr, val);
1377
1378 if (k->set_config) {
1379 k->set_config(vdev, vdev->config);
1380 }
1381 }
1382
1383 void virtio_config_modern_writew(VirtIODevice *vdev,
1384 uint32_t addr, uint32_t data)
1385 {
1386 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1387 uint16_t val = data;
1388
1389 if (addr + sizeof(val) > vdev->config_len) {
1390 return;
1391 }
1392
1393 stw_le_p(vdev->config + addr, val);
1394
1395 if (k->set_config) {
1396 k->set_config(vdev, vdev->config);
1397 }
1398 }
1399
1400 void virtio_config_modern_writel(VirtIODevice *vdev,
1401 uint32_t addr, uint32_t data)
1402 {
1403 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1404 uint32_t val = data;
1405
1406 if (addr + sizeof(val) > vdev->config_len) {
1407 return;
1408 }
1409
1410 stl_le_p(vdev->config + addr, val);
1411
1412 if (k->set_config) {
1413 k->set_config(vdev, vdev->config);
1414 }
1415 }
1416
1417 void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr)
1418 {
1419 vdev->vq[n].vring.desc = addr;
1420 virtio_queue_update_rings(vdev, n);
1421 }
1422
1423 hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n)
1424 {
1425 return vdev->vq[n].vring.desc;
1426 }
1427
1428 void virtio_queue_set_rings(VirtIODevice *vdev, int n, hwaddr desc,
1429 hwaddr avail, hwaddr used)
1430 {
1431 vdev->vq[n].vring.desc = desc;
1432 vdev->vq[n].vring.avail = avail;
1433 vdev->vq[n].vring.used = used;
1434 virtio_init_region_cache(vdev, n);
1435 }
1436
1437 void virtio_queue_set_num(VirtIODevice *vdev, int n, int num)
1438 {
1439 /* Don't allow guest to flip queue between existent and
1440 * nonexistent states, or to set it to an invalid size.
1441 */
1442 if (!!num != !!vdev->vq[n].vring.num ||
1443 num > VIRTQUEUE_MAX_SIZE ||
1444 num < 0) {
1445 return;
1446 }
1447 vdev->vq[n].vring.num = num;
1448 }
1449
1450 VirtQueue *virtio_vector_first_queue(VirtIODevice *vdev, uint16_t vector)
1451 {
1452 return QLIST_FIRST(&vdev->vector_queues[vector]);
1453 }
1454
1455 VirtQueue *virtio_vector_next_queue(VirtQueue *vq)
1456 {
1457 return QLIST_NEXT(vq, node);
1458 }
1459
1460 int virtio_queue_get_num(VirtIODevice *vdev, int n)
1461 {
1462 return vdev->vq[n].vring.num;
1463 }
1464
1465 int virtio_queue_get_max_num(VirtIODevice *vdev, int n)
1466 {
1467 return vdev->vq[n].vring.num_default;
1468 }
1469
1470 int virtio_get_num_queues(VirtIODevice *vdev)
1471 {
1472 int i;
1473
1474 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
1475 if (!virtio_queue_get_num(vdev, i)) {
1476 break;
1477 }
1478 }
1479
1480 return i;
1481 }
1482
1483 void virtio_queue_set_align(VirtIODevice *vdev, int n, int align)
1484 {
1485 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1486 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1487
1488 /* virtio-1 compliant devices cannot change the alignment */
1489 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
1490 error_report("tried to modify queue alignment for virtio-1 device");
1491 return;
1492 }
1493 /* Check that the transport told us it was going to do this
1494 * (so a buggy transport will immediately assert rather than
1495 * silently failing to migrate this state)
1496 */
1497 assert(k->has_variable_vring_alignment);
1498
1499 vdev->vq[n].vring.align = align;
1500 virtio_queue_update_rings(vdev, n);
1501 }
1502
1503 static bool virtio_queue_notify_aio_vq(VirtQueue *vq)
1504 {
1505 if (vq->vring.desc && vq->handle_aio_output) {
1506 VirtIODevice *vdev = vq->vdev;
1507
1508 trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
1509 return vq->handle_aio_output(vdev, vq);
1510 }
1511
1512 return false;
1513 }
1514
1515 static void virtio_queue_notify_vq(VirtQueue *vq)
1516 {
1517 if (vq->vring.desc && vq->handle_output) {
1518 VirtIODevice *vdev = vq->vdev;
1519
1520 if (unlikely(vdev->broken)) {
1521 return;
1522 }
1523
1524 trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
1525 vq->handle_output(vdev, vq);
1526 }
1527 }
1528
1529 void virtio_queue_notify(VirtIODevice *vdev, int n)
1530 {
1531 virtio_queue_notify_vq(&vdev->vq[n]);
1532 }
1533
1534 uint16_t virtio_queue_vector(VirtIODevice *vdev, int n)
1535 {
1536 return n < VIRTIO_QUEUE_MAX ? vdev->vq[n].vector :
1537 VIRTIO_NO_VECTOR;
1538 }
1539
1540 void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector)
1541 {
1542 VirtQueue *vq = &vdev->vq[n];
1543
1544 if (n < VIRTIO_QUEUE_MAX) {
1545 if (vdev->vector_queues &&
1546 vdev->vq[n].vector != VIRTIO_NO_VECTOR) {
1547 QLIST_REMOVE(vq, node);
1548 }
1549 vdev->vq[n].vector = vector;
1550 if (vdev->vector_queues &&
1551 vector != VIRTIO_NO_VECTOR) {
1552 QLIST_INSERT_HEAD(&vdev->vector_queues[vector], vq, node);
1553 }
1554 }
1555 }
1556
1557 VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,
1558 VirtIOHandleOutput handle_output)
1559 {
1560 int i;
1561
1562 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
1563 if (vdev->vq[i].vring.num == 0)
1564 break;
1565 }
1566
1567 if (i == VIRTIO_QUEUE_MAX || queue_size > VIRTQUEUE_MAX_SIZE)
1568 abort();
1569
1570 vdev->vq[i].vring.num = queue_size;
1571 vdev->vq[i].vring.num_default = queue_size;
1572 vdev->vq[i].vring.align = VIRTIO_PCI_VRING_ALIGN;
1573 vdev->vq[i].handle_output = handle_output;
1574 vdev->vq[i].handle_aio_output = NULL;
1575
1576 return &vdev->vq[i];
1577 }
1578
1579 void virtio_del_queue(VirtIODevice *vdev, int n)
1580 {
1581 if (n < 0 || n >= VIRTIO_QUEUE_MAX) {
1582 abort();
1583 }
1584
1585 vdev->vq[n].vring.num = 0;
1586 vdev->vq[n].vring.num_default = 0;
1587 }
1588
1589 static void virtio_set_isr(VirtIODevice *vdev, int value)
1590 {
1591 uint8_t old = atomic_read(&vdev->isr);
1592
1593 /* Do not write ISR if it does not change, so that its cacheline remains
1594 * shared in the common case where the guest does not read it.
1595 */
1596 if ((old & value) != value) {
1597 atomic_or(&vdev->isr, value);
1598 }
1599 }
1600
1601 /* Called within rcu_read_lock(). */
1602 static bool virtio_should_notify(VirtIODevice *vdev, VirtQueue *vq)
1603 {
1604 uint16_t old, new;
1605 bool v;
1606 /* We need to expose used array entries before checking used event. */
1607 smp_mb();
1608 /* Always notify when queue is empty (when feature acknowledge) */
1609 if (virtio_vdev_has_feature(vdev, VIRTIO_F_NOTIFY_ON_EMPTY) &&
1610 !vq->inuse && virtio_queue_empty(vq)) {
1611 return true;
1612 }
1613
1614 if (!virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
1615 return !(vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT);
1616 }
1617
1618 v = vq->signalled_used_valid;
1619 vq->signalled_used_valid = true;
1620 old = vq->signalled_used;
1621 new = vq->signalled_used = vq->used_idx;
1622 return !v || vring_need_event(vring_get_used_event(vq), new, old);
1623 }
1624
1625 void virtio_notify_irqfd(VirtIODevice *vdev, VirtQueue *vq)
1626 {
1627 bool should_notify;
1628 rcu_read_lock();
1629 should_notify = virtio_should_notify(vdev, vq);
1630 rcu_read_unlock();
1631
1632 if (!should_notify) {
1633 return;
1634 }
1635
1636 trace_virtio_notify_irqfd(vdev, vq);
1637
1638 /*
1639 * virtio spec 1.0 says ISR bit 0 should be ignored with MSI, but
1640 * windows drivers included in virtio-win 1.8.0 (circa 2015) are
1641 * incorrectly polling this bit during crashdump and hibernation
1642 * in MSI mode, causing a hang if this bit is never updated.
1643 * Recent releases of Windows do not really shut down, but rather
1644 * log out and hibernate to make the next startup faster. Hence,
1645 * this manifested as a more serious hang during shutdown with
1646 *
1647 * Next driver release from 2016 fixed this problem, so working around it
1648 * is not a must, but it's easy to do so let's do it here.
1649 *
1650 * Note: it's safe to update ISR from any thread as it was switched
1651 * to an atomic operation.
1652 */
1653 virtio_set_isr(vq->vdev, 0x1);
1654 event_notifier_set(&vq->guest_notifier);
1655 }
1656
1657 static void virtio_irq(VirtQueue *vq)
1658 {
1659 virtio_set_isr(vq->vdev, 0x1);
1660 virtio_notify_vector(vq->vdev, vq->vector);
1661 }
1662
1663 void virtio_notify(VirtIODevice *vdev, VirtQueue *vq)
1664 {
1665 bool should_notify;
1666 rcu_read_lock();
1667 should_notify = virtio_should_notify(vdev, vq);
1668 rcu_read_unlock();
1669
1670 if (!should_notify) {
1671 return;
1672 }
1673
1674 trace_virtio_notify(vdev, vq);
1675 virtio_irq(vq);
1676 }
1677
1678 void virtio_notify_config(VirtIODevice *vdev)
1679 {
1680 if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK))
1681 return;
1682
1683 virtio_set_isr(vdev, 0x3);
1684 vdev->generation++;
1685 virtio_notify_vector(vdev, vdev->config_vector);
1686 }
1687
1688 static bool virtio_device_endian_needed(void *opaque)
1689 {
1690 VirtIODevice *vdev = opaque;
1691
1692 assert(vdev->device_endian != VIRTIO_DEVICE_ENDIAN_UNKNOWN);
1693 if (!virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
1694 return vdev->device_endian != virtio_default_endian();
1695 }
1696 /* Devices conforming to VIRTIO 1.0 or later are always LE. */
1697 return vdev->device_endian != VIRTIO_DEVICE_ENDIAN_LITTLE;
1698 }
1699
1700 static bool virtio_64bit_features_needed(void *opaque)
1701 {
1702 VirtIODevice *vdev = opaque;
1703
1704 return (vdev->host_features >> 32) != 0;
1705 }
1706
1707 static bool virtio_virtqueue_needed(void *opaque)
1708 {
1709 VirtIODevice *vdev = opaque;
1710
1711 return virtio_host_has_feature(vdev, VIRTIO_F_VERSION_1);
1712 }
1713
1714 static bool virtio_ringsize_needed(void *opaque)
1715 {
1716 VirtIODevice *vdev = opaque;
1717 int i;
1718
1719 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
1720 if (vdev->vq[i].vring.num != vdev->vq[i].vring.num_default) {
1721 return true;
1722 }
1723 }
1724 return false;
1725 }
1726
1727 static bool virtio_extra_state_needed(void *opaque)
1728 {
1729 VirtIODevice *vdev = opaque;
1730 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1731 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1732
1733 return k->has_extra_state &&
1734 k->has_extra_state(qbus->parent);
1735 }
1736
1737 static bool virtio_broken_needed(void *opaque)
1738 {
1739 VirtIODevice *vdev = opaque;
1740
1741 return vdev->broken;
1742 }
1743
1744 static const VMStateDescription vmstate_virtqueue = {
1745 .name = "virtqueue_state",
1746 .version_id = 1,
1747 .minimum_version_id = 1,
1748 .fields = (VMStateField[]) {
1749 VMSTATE_UINT64(vring.avail, struct VirtQueue),
1750 VMSTATE_UINT64(vring.used, struct VirtQueue),
1751 VMSTATE_END_OF_LIST()
1752 }
1753 };
1754
1755 static const VMStateDescription vmstate_virtio_virtqueues = {
1756 .name = "virtio/virtqueues",
1757 .version_id = 1,
1758 .minimum_version_id = 1,
1759 .needed = &virtio_virtqueue_needed,
1760 .fields = (VMStateField[]) {
1761 VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice,
1762 VIRTIO_QUEUE_MAX, 0, vmstate_virtqueue, VirtQueue),
1763 VMSTATE_END_OF_LIST()
1764 }
1765 };
1766
1767 static const VMStateDescription vmstate_ringsize = {
1768 .name = "ringsize_state",
1769 .version_id = 1,
1770 .minimum_version_id = 1,
1771 .fields = (VMStateField[]) {
1772 VMSTATE_UINT32(vring.num_default, struct VirtQueue),
1773 VMSTATE_END_OF_LIST()
1774 }
1775 };
1776
1777 static const VMStateDescription vmstate_virtio_ringsize = {
1778 .name = "virtio/ringsize",
1779 .version_id = 1,
1780 .minimum_version_id = 1,
1781 .needed = &virtio_ringsize_needed,
1782 .fields = (VMStateField[]) {
1783 VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice,
1784 VIRTIO_QUEUE_MAX, 0, vmstate_ringsize, VirtQueue),
1785 VMSTATE_END_OF_LIST()
1786 }
1787 };
1788
1789 static int get_extra_state(QEMUFile *f, void *pv, size_t size,
1790 VMStateField *field)
1791 {
1792 VirtIODevice *vdev = pv;
1793 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1794 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1795
1796 if (!k->load_extra_state) {
1797 return -1;
1798 } else {
1799 return k->load_extra_state(qbus->parent, f);
1800 }
1801 }
1802
1803 static int put_extra_state(QEMUFile *f, void *pv, size_t size,
1804 VMStateField *field, QJSON *vmdesc)
1805 {
1806 VirtIODevice *vdev = pv;
1807 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1808 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1809
1810 k->save_extra_state(qbus->parent, f);
1811 return 0;
1812 }
1813
1814 static const VMStateInfo vmstate_info_extra_state = {
1815 .name = "virtqueue_extra_state",
1816 .get = get_extra_state,
1817 .put = put_extra_state,
1818 };
1819
1820 static const VMStateDescription vmstate_virtio_extra_state = {
1821 .name = "virtio/extra_state",
1822 .version_id = 1,
1823 .minimum_version_id = 1,
1824 .needed = &virtio_extra_state_needed,
1825 .fields = (VMStateField[]) {
1826 {
1827 .name = "extra_state",
1828 .version_id = 0,
1829 .field_exists = NULL,
1830 .size = 0,
1831 .info = &vmstate_info_extra_state,
1832 .flags = VMS_SINGLE,
1833 .offset = 0,
1834 },
1835 VMSTATE_END_OF_LIST()
1836 }
1837 };
1838
1839 static const VMStateDescription vmstate_virtio_device_endian = {
1840 .name = "virtio/device_endian",
1841 .version_id = 1,
1842 .minimum_version_id = 1,
1843 .needed = &virtio_device_endian_needed,
1844 .fields = (VMStateField[]) {
1845 VMSTATE_UINT8(device_endian, VirtIODevice),
1846 VMSTATE_END_OF_LIST()
1847 }
1848 };
1849
1850 static const VMStateDescription vmstate_virtio_64bit_features = {
1851 .name = "virtio/64bit_features",
1852 .version_id = 1,
1853 .minimum_version_id = 1,
1854 .needed = &virtio_64bit_features_needed,
1855 .fields = (VMStateField[]) {
1856 VMSTATE_UINT64(guest_features, VirtIODevice),
1857 VMSTATE_END_OF_LIST()
1858 }
1859 };
1860
1861 static const VMStateDescription vmstate_virtio_broken = {
1862 .name = "virtio/broken",
1863 .version_id = 1,
1864 .minimum_version_id = 1,
1865 .needed = &virtio_broken_needed,
1866 .fields = (VMStateField[]) {
1867 VMSTATE_BOOL(broken, VirtIODevice),
1868 VMSTATE_END_OF_LIST()
1869 }
1870 };
1871
1872 static const VMStateDescription vmstate_virtio = {
1873 .name = "virtio",
1874 .version_id = 1,
1875 .minimum_version_id = 1,
1876 .minimum_version_id_old = 1,
1877 .fields = (VMStateField[]) {
1878 VMSTATE_END_OF_LIST()
1879 },
1880 .subsections = (const VMStateDescription*[]) {
1881 &vmstate_virtio_device_endian,
1882 &vmstate_virtio_64bit_features,
1883 &vmstate_virtio_virtqueues,
1884 &vmstate_virtio_ringsize,
1885 &vmstate_virtio_broken,
1886 &vmstate_virtio_extra_state,
1887 NULL
1888 }
1889 };
1890
1891 void virtio_save(VirtIODevice *vdev, QEMUFile *f)
1892 {
1893 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1894 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1895 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
1896 uint32_t guest_features_lo = (vdev->guest_features & 0xffffffff);
1897 int i;
1898
1899 if (k->save_config) {
1900 k->save_config(qbus->parent, f);
1901 }
1902
1903 qemu_put_8s(f, &vdev->status);
1904 qemu_put_8s(f, &vdev->isr);
1905 qemu_put_be16s(f, &vdev->queue_sel);
1906 qemu_put_be32s(f, &guest_features_lo);
1907 qemu_put_be32(f, vdev->config_len);
1908 qemu_put_buffer(f, vdev->config, vdev->config_len);
1909
1910 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
1911 if (vdev->vq[i].vring.num == 0)
1912 break;
1913 }
1914
1915 qemu_put_be32(f, i);
1916
1917 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
1918 if (vdev->vq[i].vring.num == 0)
1919 break;
1920
1921 qemu_put_be32(f, vdev->vq[i].vring.num);
1922 if (k->has_variable_vring_alignment) {
1923 qemu_put_be32(f, vdev->vq[i].vring.align);
1924 }
1925 /*
1926 * Save desc now, the rest of the ring addresses are saved in
1927 * subsections for VIRTIO-1 devices.
1928 */
1929 qemu_put_be64(f, vdev->vq[i].vring.desc);
1930 qemu_put_be16s(f, &vdev->vq[i].last_avail_idx);
1931 if (k->save_queue) {
1932 k->save_queue(qbus->parent, i, f);
1933 }
1934 }
1935
1936 if (vdc->save != NULL) {
1937 vdc->save(vdev, f);
1938 }
1939
1940 if (vdc->vmsd) {
1941 vmstate_save_state(f, vdc->vmsd, vdev, NULL);
1942 }
1943
1944 /* Subsections */
1945 vmstate_save_state(f, &vmstate_virtio, vdev, NULL);
1946 }
1947
1948 /* A wrapper for use as a VMState .put function */
1949 static int virtio_device_put(QEMUFile *f, void *opaque, size_t size,
1950 VMStateField *field, QJSON *vmdesc)
1951 {
1952 virtio_save(VIRTIO_DEVICE(opaque), f);
1953
1954 return 0;
1955 }
1956
1957 /* A wrapper for use as a VMState .get function */
1958 static int virtio_device_get(QEMUFile *f, void *opaque, size_t size,
1959 VMStateField *field)
1960 {
1961 VirtIODevice *vdev = VIRTIO_DEVICE(opaque);
1962 DeviceClass *dc = DEVICE_CLASS(VIRTIO_DEVICE_GET_CLASS(vdev));
1963
1964 return virtio_load(vdev, f, dc->vmsd->version_id);
1965 }
1966
1967 const VMStateInfo virtio_vmstate_info = {
1968 .name = "virtio",
1969 .get = virtio_device_get,
1970 .put = virtio_device_put,
1971 };
1972
1973 static int virtio_set_features_nocheck(VirtIODevice *vdev, uint64_t val)
1974 {
1975 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1976 bool bad = (val & ~(vdev->host_features)) != 0;
1977
1978 val &= vdev->host_features;
1979 if (k->set_features) {
1980 k->set_features(vdev, val);
1981 }
1982 vdev->guest_features = val;
1983 return bad ? -1 : 0;
1984 }
1985
1986 int virtio_set_features(VirtIODevice *vdev, uint64_t val)
1987 {
1988 /*
1989 * The driver must not attempt to set features after feature negotiation
1990 * has finished.
1991 */
1992 if (vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) {
1993 return -EINVAL;
1994 }
1995 return virtio_set_features_nocheck(vdev, val);
1996 }
1997
1998 int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id)
1999 {
2000 int i, ret;
2001 int32_t config_len;
2002 uint32_t num;
2003 uint32_t features;
2004 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2005 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2006 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
2007
2008 /*
2009 * We poison the endianness to ensure it does not get used before
2010 * subsections have been loaded.
2011 */
2012 vdev->device_endian = VIRTIO_DEVICE_ENDIAN_UNKNOWN;
2013
2014 if (k->load_config) {
2015 ret = k->load_config(qbus->parent, f);
2016 if (ret)
2017 return ret;
2018 }
2019
2020 qemu_get_8s(f, &vdev->status);
2021 qemu_get_8s(f, &vdev->isr);
2022 qemu_get_be16s(f, &vdev->queue_sel);
2023 if (vdev->queue_sel >= VIRTIO_QUEUE_MAX) {
2024 return -1;
2025 }
2026 qemu_get_be32s(f, &features);
2027
2028 /*
2029 * Temporarily set guest_features low bits - needed by
2030 * virtio net load code testing for VIRTIO_NET_F_CTRL_GUEST_OFFLOADS
2031 * VIRTIO_NET_F_GUEST_ANNOUNCE and VIRTIO_NET_F_CTRL_VQ.
2032 *
2033 * Note: devices should always test host features in future - don't create
2034 * new dependencies like this.
2035 */
2036 vdev->guest_features = features;
2037
2038 config_len = qemu_get_be32(f);
2039
2040 /*
2041 * There are cases where the incoming config can be bigger or smaller
2042 * than what we have; so load what we have space for, and skip
2043 * any excess that's in the stream.
2044 */
2045 qemu_get_buffer(f, vdev->config, MIN(config_len, vdev->config_len));
2046
2047 while (config_len > vdev->config_len) {
2048 qemu_get_byte(f);
2049 config_len--;
2050 }
2051
2052 num = qemu_get_be32(f);
2053
2054 if (num > VIRTIO_QUEUE_MAX) {
2055 error_report("Invalid number of virtqueues: 0x%x", num);
2056 return -1;
2057 }
2058
2059 for (i = 0; i < num; i++) {
2060 vdev->vq[i].vring.num = qemu_get_be32(f);
2061 if (k->has_variable_vring_alignment) {
2062 vdev->vq[i].vring.align = qemu_get_be32(f);
2063 }
2064 vdev->vq[i].vring.desc = qemu_get_be64(f);
2065 qemu_get_be16s(f, &vdev->vq[i].last_avail_idx);
2066 vdev->vq[i].signalled_used_valid = false;
2067 vdev->vq[i].notification = true;
2068
2069 if (!vdev->vq[i].vring.desc && vdev->vq[i].last_avail_idx) {
2070 error_report("VQ %d address 0x0 "
2071 "inconsistent with Host index 0x%x",
2072 i, vdev->vq[i].last_avail_idx);
2073 return -1;
2074 }
2075 if (k->load_queue) {
2076 ret = k->load_queue(qbus->parent, i, f);
2077 if (ret)
2078 return ret;
2079 }
2080 }
2081
2082 virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
2083
2084 if (vdc->load != NULL) {
2085 ret = vdc->load(vdev, f, version_id);
2086 if (ret) {
2087 return ret;
2088 }
2089 }
2090
2091 if (vdc->vmsd) {
2092 ret = vmstate_load_state(f, vdc->vmsd, vdev, version_id);
2093 if (ret) {
2094 return ret;
2095 }
2096 }
2097
2098 /* Subsections */
2099 ret = vmstate_load_state(f, &vmstate_virtio, vdev, 1);
2100 if (ret) {
2101 return ret;
2102 }
2103
2104 if (vdev->device_endian == VIRTIO_DEVICE_ENDIAN_UNKNOWN) {
2105 vdev->device_endian = virtio_default_endian();
2106 }
2107
2108 if (virtio_64bit_features_needed(vdev)) {
2109 /*
2110 * Subsection load filled vdev->guest_features. Run them
2111 * through virtio_set_features to sanity-check them against
2112 * host_features.
2113 */
2114 uint64_t features64 = vdev->guest_features;
2115 if (virtio_set_features_nocheck(vdev, features64) < 0) {
2116 error_report("Features 0x%" PRIx64 " unsupported. "
2117 "Allowed features: 0x%" PRIx64,
2118 features64, vdev->host_features);
2119 return -1;
2120 }
2121 } else {
2122 if (virtio_set_features_nocheck(vdev, features) < 0) {
2123 error_report("Features 0x%x unsupported. "
2124 "Allowed features: 0x%" PRIx64,
2125 features, vdev->host_features);
2126 return -1;
2127 }
2128 }
2129
2130 rcu_read_lock();
2131 for (i = 0; i < num; i++) {
2132 if (vdev->vq[i].vring.desc) {
2133 uint16_t nheads;
2134
2135 /*
2136 * VIRTIO-1 devices migrate desc, used, and avail ring addresses so
2137 * only the region cache needs to be set up. Legacy devices need
2138 * to calculate used and avail ring addresses based on the desc
2139 * address.
2140 */
2141 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
2142 virtio_init_region_cache(vdev, i);
2143 } else {
2144 virtio_queue_update_rings(vdev, i);
2145 }
2146
2147 nheads = vring_avail_idx(&vdev->vq[i]) - vdev->vq[i].last_avail_idx;
2148 /* Check it isn't doing strange things with descriptor numbers. */
2149 if (nheads > vdev->vq[i].vring.num) {
2150 error_report("VQ %d size 0x%x Guest index 0x%x "
2151 "inconsistent with Host index 0x%x: delta 0x%x",
2152 i, vdev->vq[i].vring.num,
2153 vring_avail_idx(&vdev->vq[i]),
2154 vdev->vq[i].last_avail_idx, nheads);
2155 return -1;
2156 }
2157 vdev->vq[i].used_idx = vring_used_idx(&vdev->vq[i]);
2158 vdev->vq[i].shadow_avail_idx = vring_avail_idx(&vdev->vq[i]);
2159
2160 /*
2161 * Some devices migrate VirtQueueElements that have been popped
2162 * from the avail ring but not yet returned to the used ring.
2163 * Since max ring size < UINT16_MAX it's safe to use modulo
2164 * UINT16_MAX + 1 subtraction.
2165 */
2166 vdev->vq[i].inuse = (uint16_t)(vdev->vq[i].last_avail_idx -
2167 vdev->vq[i].used_idx);
2168 if (vdev->vq[i].inuse > vdev->vq[i].vring.num) {
2169 error_report("VQ %d size 0x%x < last_avail_idx 0x%x - "
2170 "used_idx 0x%x",
2171 i, vdev->vq[i].vring.num,
2172 vdev->vq[i].last_avail_idx,
2173 vdev->vq[i].used_idx);
2174 return -1;
2175 }
2176 }
2177 }
2178 rcu_read_unlock();
2179
2180 return 0;
2181 }
2182
2183 void virtio_cleanup(VirtIODevice *vdev)
2184 {
2185 qemu_del_vm_change_state_handler(vdev->vmstate);
2186 }
2187
2188 static void virtio_vmstate_change(void *opaque, int running, RunState state)
2189 {
2190 VirtIODevice *vdev = opaque;
2191 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2192 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2193 bool backend_run = running && (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK);
2194 vdev->vm_running = running;
2195
2196 if (backend_run) {
2197 virtio_set_status(vdev, vdev->status);
2198 }
2199
2200 if (k->vmstate_change) {
2201 k->vmstate_change(qbus->parent, backend_run);
2202 }
2203
2204 if (!backend_run) {
2205 virtio_set_status(vdev, vdev->status);
2206 }
2207 }
2208
2209 void virtio_instance_init_common(Object *proxy_obj, void *data,
2210 size_t vdev_size, const char *vdev_name)
2211 {
2212 DeviceState *vdev = data;
2213
2214 object_initialize(vdev, vdev_size, vdev_name);
2215 object_property_add_child(proxy_obj, "virtio-backend", OBJECT(vdev), NULL);
2216 object_unref(OBJECT(vdev));
2217 qdev_alias_all_properties(vdev, proxy_obj);
2218 }
2219
2220 void virtio_init(VirtIODevice *vdev, const char *name,
2221 uint16_t device_id, size_t config_size)
2222 {
2223 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2224 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2225 int i;
2226 int nvectors = k->query_nvectors ? k->query_nvectors(qbus->parent) : 0;
2227
2228 if (nvectors) {
2229 vdev->vector_queues =
2230 g_malloc0(sizeof(*vdev->vector_queues) * nvectors);
2231 }
2232
2233 vdev->device_id = device_id;
2234 vdev->status = 0;
2235 atomic_set(&vdev->isr, 0);
2236 vdev->queue_sel = 0;
2237 vdev->config_vector = VIRTIO_NO_VECTOR;
2238 vdev->vq = g_malloc0(sizeof(VirtQueue) * VIRTIO_QUEUE_MAX);
2239 vdev->vm_running = runstate_is_running();
2240 vdev->broken = false;
2241 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2242 vdev->vq[i].vector = VIRTIO_NO_VECTOR;
2243 vdev->vq[i].vdev = vdev;
2244 vdev->vq[i].queue_index = i;
2245 }
2246
2247 vdev->name = name;
2248 vdev->config_len = config_size;
2249 if (vdev->config_len) {
2250 vdev->config = g_malloc0(config_size);
2251 } else {
2252 vdev->config = NULL;
2253 }
2254 vdev->vmstate = qemu_add_vm_change_state_handler(virtio_vmstate_change,
2255 vdev);
2256 vdev->device_endian = virtio_default_endian();
2257 vdev->use_guest_notifier_mask = true;
2258 }
2259
2260 hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n)
2261 {
2262 return vdev->vq[n].vring.desc;
2263 }
2264
2265 hwaddr virtio_queue_get_avail_addr(VirtIODevice *vdev, int n)
2266 {
2267 return vdev->vq[n].vring.avail;
2268 }
2269
2270 hwaddr virtio_queue_get_used_addr(VirtIODevice *vdev, int n)
2271 {
2272 return vdev->vq[n].vring.used;
2273 }
2274
2275 hwaddr virtio_queue_get_desc_size(VirtIODevice *vdev, int n)
2276 {
2277 return sizeof(VRingDesc) * vdev->vq[n].vring.num;
2278 }
2279
2280 hwaddr virtio_queue_get_avail_size(VirtIODevice *vdev, int n)
2281 {
2282 return offsetof(VRingAvail, ring) +
2283 sizeof(uint16_t) * vdev->vq[n].vring.num;
2284 }
2285
2286 hwaddr virtio_queue_get_used_size(VirtIODevice *vdev, int n)
2287 {
2288 return offsetof(VRingUsed, ring) +
2289 sizeof(VRingUsedElem) * vdev->vq[n].vring.num;
2290 }
2291
2292 uint16_t virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n)
2293 {
2294 return vdev->vq[n].last_avail_idx;
2295 }
2296
2297 void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t idx)
2298 {
2299 vdev->vq[n].last_avail_idx = idx;
2300 vdev->vq[n].shadow_avail_idx = idx;
2301 }
2302
2303 void virtio_queue_update_used_idx(VirtIODevice *vdev, int n)
2304 {
2305 rcu_read_lock();
2306 if (vdev->vq[n].vring.desc) {
2307 vdev->vq[n].used_idx = vring_used_idx(&vdev->vq[n]);
2308 }
2309 rcu_read_unlock();
2310 }
2311
2312 void virtio_queue_invalidate_signalled_used(VirtIODevice *vdev, int n)
2313 {
2314 vdev->vq[n].signalled_used_valid = false;
2315 }
2316
2317 VirtQueue *virtio_get_queue(VirtIODevice *vdev, int n)
2318 {
2319 return vdev->vq + n;
2320 }
2321
2322 uint16_t virtio_get_queue_index(VirtQueue *vq)
2323 {
2324 return vq->queue_index;
2325 }
2326
2327 static void virtio_queue_guest_notifier_read(EventNotifier *n)
2328 {
2329 VirtQueue *vq = container_of(n, VirtQueue, guest_notifier);
2330 if (event_notifier_test_and_clear(n)) {
2331 virtio_irq(vq);
2332 }
2333 }
2334
2335 void virtio_queue_set_guest_notifier_fd_handler(VirtQueue *vq, bool assign,
2336 bool with_irqfd)
2337 {
2338 if (assign && !with_irqfd) {
2339 event_notifier_set_handler(&vq->guest_notifier,
2340 virtio_queue_guest_notifier_read);
2341 } else {
2342 event_notifier_set_handler(&vq->guest_notifier, NULL);
2343 }
2344 if (!assign) {
2345 /* Test and clear notifier before closing it,
2346 * in case poll callback didn't have time to run. */
2347 virtio_queue_guest_notifier_read(&vq->guest_notifier);
2348 }
2349 }
2350
2351 EventNotifier *virtio_queue_get_guest_notifier(VirtQueue *vq)
2352 {
2353 return &vq->guest_notifier;
2354 }
2355
2356 static void virtio_queue_host_notifier_aio_read(EventNotifier *n)
2357 {
2358 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
2359 if (event_notifier_test_and_clear(n)) {
2360 virtio_queue_notify_aio_vq(vq);
2361 }
2362 }
2363
2364 static void virtio_queue_host_notifier_aio_poll_begin(EventNotifier *n)
2365 {
2366 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
2367
2368 virtio_queue_set_notification(vq, 0);
2369 }
2370
2371 static bool virtio_queue_host_notifier_aio_poll(void *opaque)
2372 {
2373 EventNotifier *n = opaque;
2374 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
2375 bool progress;
2376
2377 if (!vq->vring.desc || virtio_queue_empty(vq)) {
2378 return false;
2379 }
2380
2381 progress = virtio_queue_notify_aio_vq(vq);
2382
2383 /* In case the handler function re-enabled notifications */
2384 virtio_queue_set_notification(vq, 0);
2385 return progress;
2386 }
2387
2388 static void virtio_queue_host_notifier_aio_poll_end(EventNotifier *n)
2389 {
2390 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
2391
2392 /* Caller polls once more after this to catch requests that race with us */
2393 virtio_queue_set_notification(vq, 1);
2394 }
2395
2396 void virtio_queue_aio_set_host_notifier_handler(VirtQueue *vq, AioContext *ctx,
2397 VirtIOHandleAIOOutput handle_output)
2398 {
2399 if (handle_output) {
2400 vq->handle_aio_output = handle_output;
2401 aio_set_event_notifier(ctx, &vq->host_notifier, true,
2402 virtio_queue_host_notifier_aio_read,
2403 virtio_queue_host_notifier_aio_poll);
2404 aio_set_event_notifier_poll(ctx, &vq->host_notifier,
2405 virtio_queue_host_notifier_aio_poll_begin,
2406 virtio_queue_host_notifier_aio_poll_end);
2407 } else {
2408 aio_set_event_notifier(ctx, &vq->host_notifier, true, NULL, NULL);
2409 /* Test and clear notifier before after disabling event,
2410 * in case poll callback didn't have time to run. */
2411 virtio_queue_host_notifier_aio_read(&vq->host_notifier);
2412 vq->handle_aio_output = NULL;
2413 }
2414 }
2415
2416 void virtio_queue_host_notifier_read(EventNotifier *n)
2417 {
2418 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
2419 if (event_notifier_test_and_clear(n)) {
2420 virtio_queue_notify_vq(vq);
2421 }
2422 }
2423
2424 EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq)
2425 {
2426 return &vq->host_notifier;
2427 }
2428
2429 void virtio_device_set_child_bus_name(VirtIODevice *vdev, char *bus_name)
2430 {
2431 g_free(vdev->bus_name);
2432 vdev->bus_name = g_strdup(bus_name);
2433 }
2434
2435 void GCC_FMT_ATTR(2, 3) virtio_error(VirtIODevice *vdev, const char *fmt, ...)
2436 {
2437 va_list ap;
2438
2439 va_start(ap, fmt);
2440 error_vreport(fmt, ap);
2441 va_end(ap);
2442
2443 vdev->broken = true;
2444
2445 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
2446 virtio_set_status(vdev, vdev->status | VIRTIO_CONFIG_S_NEEDS_RESET);
2447 virtio_notify_config(vdev);
2448 }
2449 }
2450
2451 static void virtio_memory_listener_commit(MemoryListener *listener)
2452 {
2453 VirtIODevice *vdev = container_of(listener, VirtIODevice, listener);
2454 int i;
2455
2456 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2457 if (vdev->vq[i].vring.num == 0) {
2458 break;
2459 }
2460 virtio_init_region_cache(vdev, i);
2461 }
2462 }
2463
2464 static void virtio_device_realize(DeviceState *dev, Error **errp)
2465 {
2466 VirtIODevice *vdev = VIRTIO_DEVICE(dev);
2467 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev);
2468 Error *err = NULL;
2469
2470 /* Devices should either use vmsd or the load/save methods */
2471 assert(!vdc->vmsd || !vdc->load);
2472
2473 if (vdc->realize != NULL) {
2474 vdc->realize(dev, &err);
2475 if (err != NULL) {
2476 error_propagate(errp, err);
2477 return;
2478 }
2479 }
2480
2481 virtio_bus_device_plugged(vdev, &err);
2482 if (err != NULL) {
2483 error_propagate(errp, err);
2484 return;
2485 }
2486
2487 vdev->listener.commit = virtio_memory_listener_commit;
2488 memory_listener_register(&vdev->listener, vdev->dma_as);
2489 }
2490
2491 static void virtio_device_unrealize(DeviceState *dev, Error **errp)
2492 {
2493 VirtIODevice *vdev = VIRTIO_DEVICE(dev);
2494 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev);
2495 Error *err = NULL;
2496
2497 virtio_bus_device_unplugged(vdev);
2498
2499 if (vdc->unrealize != NULL) {
2500 vdc->unrealize(dev, &err);
2501 if (err != NULL) {
2502 error_propagate(errp, err);
2503 return;
2504 }
2505 }
2506
2507 g_free(vdev->bus_name);
2508 vdev->bus_name = NULL;
2509 }
2510
2511 static void virtio_device_free_virtqueues(VirtIODevice *vdev)
2512 {
2513 int i;
2514 if (!vdev->vq) {
2515 return;
2516 }
2517
2518 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2519 if (vdev->vq[i].vring.num == 0) {
2520 break;
2521 }
2522 virtio_virtqueue_reset_region_cache(&vdev->vq[i]);
2523 }
2524 g_free(vdev->vq);
2525 }
2526
2527 static void virtio_device_instance_finalize(Object *obj)
2528 {
2529 VirtIODevice *vdev = VIRTIO_DEVICE(obj);
2530
2531 memory_listener_unregister(&vdev->listener);
2532 virtio_device_free_virtqueues(vdev);
2533
2534 g_free(vdev->config);
2535 g_free(vdev->vector_queues);
2536 }
2537
2538 static Property virtio_properties[] = {
2539 DEFINE_VIRTIO_COMMON_FEATURES(VirtIODevice, host_features),
2540 DEFINE_PROP_END_OF_LIST(),
2541 };
2542
2543 static int virtio_device_start_ioeventfd_impl(VirtIODevice *vdev)
2544 {
2545 VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev)));
2546 int n, r, err;
2547
2548 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
2549 VirtQueue *vq = &vdev->vq[n];
2550 if (!virtio_queue_get_num(vdev, n)) {
2551 continue;
2552 }
2553 r = virtio_bus_set_host_notifier(qbus, n, true);
2554 if (r < 0) {
2555 err = r;
2556 goto assign_error;
2557 }
2558 event_notifier_set_handler(&vq->host_notifier,
2559 virtio_queue_host_notifier_read);
2560 }
2561
2562 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
2563 /* Kick right away to begin processing requests already in vring */
2564 VirtQueue *vq = &vdev->vq[n];
2565 if (!vq->vring.num) {
2566 continue;
2567 }
2568 event_notifier_set(&vq->host_notifier);
2569 }
2570 return 0;
2571
2572 assign_error:
2573 while (--n >= 0) {
2574 VirtQueue *vq = &vdev->vq[n];
2575 if (!virtio_queue_get_num(vdev, n)) {
2576 continue;
2577 }
2578
2579 event_notifier_set_handler(&vq->host_notifier, NULL);
2580 r = virtio_bus_set_host_notifier(qbus, n, false);
2581 assert(r >= 0);
2582 }
2583 return err;
2584 }
2585
2586 int virtio_device_start_ioeventfd(VirtIODevice *vdev)
2587 {
2588 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2589 VirtioBusState *vbus = VIRTIO_BUS(qbus);
2590
2591 return virtio_bus_start_ioeventfd(vbus);
2592 }
2593
2594 static void virtio_device_stop_ioeventfd_impl(VirtIODevice *vdev)
2595 {
2596 VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev)));
2597 int n, r;
2598
2599 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
2600 VirtQueue *vq = &vdev->vq[n];
2601
2602 if (!virtio_queue_get_num(vdev, n)) {
2603 continue;
2604 }
2605 event_notifier_set_handler(&vq->host_notifier, NULL);
2606 r = virtio_bus_set_host_notifier(qbus, n, false);
2607 assert(r >= 0);
2608 }
2609 }
2610
2611 void virtio_device_stop_ioeventfd(VirtIODevice *vdev)
2612 {
2613 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2614 VirtioBusState *vbus = VIRTIO_BUS(qbus);
2615
2616 virtio_bus_stop_ioeventfd(vbus);
2617 }
2618
2619 int virtio_device_grab_ioeventfd(VirtIODevice *vdev)
2620 {
2621 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2622 VirtioBusState *vbus = VIRTIO_BUS(qbus);
2623
2624 return virtio_bus_grab_ioeventfd(vbus);
2625 }
2626
2627 void virtio_device_release_ioeventfd(VirtIODevice *vdev)
2628 {
2629 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2630 VirtioBusState *vbus = VIRTIO_BUS(qbus);
2631
2632 virtio_bus_release_ioeventfd(vbus);
2633 }
2634
2635 static void virtio_device_class_init(ObjectClass *klass, void *data)
2636 {
2637 /* Set the default value here. */
2638 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
2639 DeviceClass *dc = DEVICE_CLASS(klass);
2640
2641 dc->realize = virtio_device_realize;
2642 dc->unrealize = virtio_device_unrealize;
2643 dc->bus_type = TYPE_VIRTIO_BUS;
2644 dc->props = virtio_properties;
2645 vdc->start_ioeventfd = virtio_device_start_ioeventfd_impl;
2646 vdc->stop_ioeventfd = virtio_device_stop_ioeventfd_impl;
2647
2648 vdc->legacy_features |= VIRTIO_LEGACY_FEATURES;
2649 }
2650
2651 bool virtio_device_ioeventfd_enabled(VirtIODevice *vdev)
2652 {
2653 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2654 VirtioBusState *vbus = VIRTIO_BUS(qbus);
2655
2656 return virtio_bus_ioeventfd_enabled(vbus);
2657 }
2658
2659 static const TypeInfo virtio_device_info = {
2660 .name = TYPE_VIRTIO_DEVICE,
2661 .parent = TYPE_DEVICE,
2662 .instance_size = sizeof(VirtIODevice),
2663 .class_init = virtio_device_class_init,
2664 .instance_finalize = virtio_device_instance_finalize,
2665 .abstract = true,
2666 .class_size = sizeof(VirtioDeviceClass),
2667 };
2668
2669 static void virtio_register_types(void)
2670 {
2671 type_register_static(&virtio_device_info);
2672 }
2673
2674 type_init(virtio_register_types)