?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
osdep.h: Prohibit disabling assert() in supported builds
[qemu/kevin.git] / hw / virtio / virtio.c
blob3129d25c0018b001dc0cc8d43b2c4896c494e522
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 "hw/virtio/virtio-access.h"
25 #include "sysemu/dma.h"
26
27 /*
28 * The alignment to use between consumer and producer parts of vring.
29 * x86 pagesize again. This is the default, used by transports like PCI
30 * which don't provide a means for the guest to tell the host the alignment.
31 */
32 #define VIRTIO_PCI_VRING_ALIGN 4096
33
34 typedef struct VRingDesc
35 {
36 uint64_t addr;
37 uint32_t len;
38 uint16_t flags;
39 uint16_t next;
40 } VRingDesc;
41
42 typedef struct VRingAvail
43 {
44 uint16_t flags;
45 uint16_t idx;
46 uint16_t ring[0];
47 } VRingAvail;
48
49 typedef struct VRingUsedElem
50 {
51 uint32_t id;
52 uint32_t len;
53 } VRingUsedElem;
54
55 typedef struct VRingUsed
56 {
57 uint16_t flags;
58 uint16_t idx;
59 VRingUsedElem ring[0];
60 } VRingUsed;
61
62 typedef struct VRingMemoryRegionCaches {
63 struct rcu_head rcu;
64 MemoryRegionCache desc;
65 MemoryRegionCache avail;
66 MemoryRegionCache used;
67 } VRingMemoryRegionCaches;
68
69 typedef struct VRing
70 {
71 unsigned int num;
72 unsigned int num_default;
73 unsigned int align;
74 hwaddr desc;
75 hwaddr avail;
76 hwaddr used;
77 VRingMemoryRegionCaches *caches;
78 } VRing;
79
80 struct VirtQueue
81 {
82 VRing vring;
83
84 /* Next head to pop */
85 uint16_t last_avail_idx;
86
87 /* Last avail_idx read from VQ. */
88 uint16_t shadow_avail_idx;
89
90 uint16_t used_idx;
91
92 /* Last used index value we have signalled on */
93 uint16_t signalled_used;
94
95 /* Last used index value we have signalled on */
96 bool signalled_used_valid;
97
98 /* Notification enabled? */
99 bool notification;
100
101 uint16_t queue_index;
102
103 unsigned int inuse;
104
105 uint16_t vector;
106 VirtIOHandleOutput handle_output;
107 VirtIOHandleAIOOutput handle_aio_output;
108 VirtIODevice *vdev;
109 EventNotifier guest_notifier;
110 EventNotifier host_notifier;
111 QLIST_ENTRY(VirtQueue) node;
112 };
113
114 static void virtio_free_region_cache(VRingMemoryRegionCaches *caches)
115 {
116 if (!caches) {
117 return;
118 }
119
120 address_space_cache_destroy(&caches->desc);
121 address_space_cache_destroy(&caches->avail);
122 address_space_cache_destroy(&caches->used);
123 g_free(caches);
124 }
125
126 static void virtio_init_region_cache(VirtIODevice *vdev, int n)
127 {
128 VirtQueue *vq = &vdev->vq[n];
129 VRingMemoryRegionCaches *old = vq->vring.caches;
130 VRingMemoryRegionCaches *new;
131 hwaddr addr, size;
132 int event_size;
133 int64_t len;
134
135 event_size = virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
136
137 addr = vq->vring.desc;
138 if (!addr) {
139 return;
140 }
141 new = g_new0(VRingMemoryRegionCaches, 1);
142 size = virtio_queue_get_desc_size(vdev, n);
143 len = address_space_cache_init(&new->desc, vdev->dma_as,
144 addr, size, false);
145 if (len < size) {
146 virtio_error(vdev, "Cannot map desc");
147 goto err_desc;
148 }
149
150 size = virtio_queue_get_used_size(vdev, n) + event_size;
151 len = address_space_cache_init(&new->used, vdev->dma_as,
152 vq->vring.used, size, true);
153 if (len < size) {
154 virtio_error(vdev, "Cannot map used");
155 goto err_used;
156 }
157
158 size = virtio_queue_get_avail_size(vdev, n) + event_size;
159 len = address_space_cache_init(&new->avail, vdev->dma_as,
160 vq->vring.avail, size, false);
161 if (len < size) {
162 virtio_error(vdev, "Cannot map avail");
163 goto err_avail;
164 }
165
166 atomic_rcu_set(&vq->vring.caches, new);
167 if (old) {
168 call_rcu(old, virtio_free_region_cache, rcu);
169 }
170 return;
171
172 err_avail:
173 address_space_cache_destroy(&new->used);
174 err_used:
175 address_space_cache_destroy(&new->desc);
176 err_desc:
177 g_free(new);
178 }
179
180 /* virt queue functions */
181 void virtio_queue_update_rings(VirtIODevice *vdev, int n)
182 {
183 VRing *vring = &vdev->vq[n].vring;
184
185 if (!vring->desc) {
186 /* not yet setup -> nothing to do */
187 return;
188 }
189 vring->avail = vring->desc + vring->num * sizeof(VRingDesc);
190 vring->used = vring_align(vring->avail +
191 offsetof(VRingAvail, ring[vring->num]),
192 vring->align);
193 virtio_init_region_cache(vdev, n);
194 }
195
196 /* Called within rcu_read_lock(). */
197 static void vring_desc_read(VirtIODevice *vdev, VRingDesc *desc,
198 MemoryRegionCache *cache, int i)
199 {
200 address_space_read_cached(cache, i * sizeof(VRingDesc),
201 desc, sizeof(VRingDesc));
202 virtio_tswap64s(vdev, &desc->addr);
203 virtio_tswap32s(vdev, &desc->len);
204 virtio_tswap16s(vdev, &desc->flags);
205 virtio_tswap16s(vdev, &desc->next);
206 }
207
208 static VRingMemoryRegionCaches *vring_get_region_caches(struct VirtQueue *vq)
209 {
210 VRingMemoryRegionCaches *caches = atomic_rcu_read(&vq->vring.caches);
211 assert(caches != NULL);
212 return caches;
213 }
214 /* Called within rcu_read_lock(). */
215 static inline uint16_t vring_avail_flags(VirtQueue *vq)
216 {
217 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
218 hwaddr pa = offsetof(VRingAvail, flags);
219 return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
220 }
221
222 /* Called within rcu_read_lock(). */
223 static inline uint16_t vring_avail_idx(VirtQueue *vq)
224 {
225 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
226 hwaddr pa = offsetof(VRingAvail, idx);
227 vq->shadow_avail_idx = virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
228 return vq->shadow_avail_idx;
229 }
230
231 /* Called within rcu_read_lock(). */
232 static inline uint16_t vring_avail_ring(VirtQueue *vq, int i)
233 {
234 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
235 hwaddr pa = offsetof(VRingAvail, ring[i]);
236 return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
237 }
238
239 /* Called within rcu_read_lock(). */
240 static inline uint16_t vring_get_used_event(VirtQueue *vq)
241 {
242 return vring_avail_ring(vq, vq->vring.num);
243 }
244
245 /* Called within rcu_read_lock(). */
246 static inline void vring_used_write(VirtQueue *vq, VRingUsedElem *uelem,
247 int i)
248 {
249 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
250 hwaddr pa = offsetof(VRingUsed, ring[i]);
251 virtio_tswap32s(vq->vdev, &uelem->id);
252 virtio_tswap32s(vq->vdev, &uelem->len);
253 address_space_write_cached(&caches->used, pa, uelem, sizeof(VRingUsedElem));
254 address_space_cache_invalidate(&caches->used, pa, sizeof(VRingUsedElem));
255 }
256
257 /* Called within rcu_read_lock(). */
258 static uint16_t vring_used_idx(VirtQueue *vq)
259 {
260 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
261 hwaddr pa = offsetof(VRingUsed, idx);
262 return virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
263 }
264
265 /* Called within rcu_read_lock(). */
266 static inline void vring_used_idx_set(VirtQueue *vq, uint16_t val)
267 {
268 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
269 hwaddr pa = offsetof(VRingUsed, idx);
270 virtio_stw_phys_cached(vq->vdev, &caches->used, pa, val);
271 address_space_cache_invalidate(&caches->used, pa, sizeof(val));
272 vq->used_idx = val;
273 }
274
275 /* Called within rcu_read_lock(). */
276 static inline void vring_used_flags_set_bit(VirtQueue *vq, int mask)
277 {
278 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
279 VirtIODevice *vdev = vq->vdev;
280 hwaddr pa = offsetof(VRingUsed, flags);
281 uint16_t flags = virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
282
283 virtio_stw_phys_cached(vdev, &caches->used, pa, flags | mask);
284 address_space_cache_invalidate(&caches->used, pa, sizeof(flags));
285 }
286
287 /* Called within rcu_read_lock(). */
288 static inline void vring_used_flags_unset_bit(VirtQueue *vq, int mask)
289 {
290 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
291 VirtIODevice *vdev = vq->vdev;
292 hwaddr pa = offsetof(VRingUsed, flags);
293 uint16_t flags = virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
294
295 virtio_stw_phys_cached(vdev, &caches->used, pa, flags & ~mask);
296 address_space_cache_invalidate(&caches->used, pa, sizeof(flags));
297 }
298
299 /* Called within rcu_read_lock(). */
300 static inline void vring_set_avail_event(VirtQueue *vq, uint16_t val)
301 {
302 VRingMemoryRegionCaches *caches;
303 hwaddr pa;
304 if (!vq->notification) {
305 return;
306 }
307
308 caches = vring_get_region_caches(vq);
309 pa = offsetof(VRingUsed, ring[vq->vring.num]);
310 virtio_stw_phys_cached(vq->vdev, &caches->used, pa, val);
311 address_space_cache_invalidate(&caches->used, pa, sizeof(val));
312 }
313
314 void virtio_queue_set_notification(VirtQueue *vq, int enable)
315 {
316 vq->notification = enable;
317
318 if (!vq->vring.desc) {
319 return;
320 }
321
322 rcu_read_lock();
323 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
324 vring_set_avail_event(vq, vring_avail_idx(vq));
325 } else if (enable) {
326 vring_used_flags_unset_bit(vq, VRING_USED_F_NO_NOTIFY);
327 } else {
328 vring_used_flags_set_bit(vq, VRING_USED_F_NO_NOTIFY);
329 }
330 if (enable) {
331 /* Expose avail event/used flags before caller checks the avail idx. */
332 smp_mb();
333 }
334 rcu_read_unlock();
335 }
336
337 int virtio_queue_ready(VirtQueue *vq)
338 {
339 return vq->vring.avail != 0;
340 }
341
342 /* Fetch avail_idx from VQ memory only when we really need to know if
343 * guest has added some buffers.
344 * Called within rcu_read_lock(). */
345 static int virtio_queue_empty_rcu(VirtQueue *vq)
346 {
347 if (unlikely(!vq->vring.avail)) {
348 return 1;
349 }
350
351 if (vq->shadow_avail_idx != vq->last_avail_idx) {
352 return 0;
353 }
354
355 return vring_avail_idx(vq) == vq->last_avail_idx;
356 }
357
358 int virtio_queue_empty(VirtQueue *vq)
359 {
360 bool empty;
361
362 if (unlikely(!vq->vring.avail)) {
363 return 1;
364 }
365
366 if (vq->shadow_avail_idx != vq->last_avail_idx) {
367 return 0;
368 }
369
370 rcu_read_lock();
371 empty = vring_avail_idx(vq) == vq->last_avail_idx;
372 rcu_read_unlock();
373 return empty;
374 }
375
376 static void virtqueue_unmap_sg(VirtQueue *vq, const VirtQueueElement *elem,
377 unsigned int len)
378 {
379 AddressSpace *dma_as = vq->vdev->dma_as;
380 unsigned int offset;
381 int i;
382
383 offset = 0;
384 for (i = 0; i < elem->in_num; i++) {
385 size_t size = MIN(len - offset, elem->in_sg[i].iov_len);
386
387 dma_memory_unmap(dma_as, elem->in_sg[i].iov_base,
388 elem->in_sg[i].iov_len,
389 DMA_DIRECTION_FROM_DEVICE, size);
390
391 offset += size;
392 }
393
394 for (i = 0; i < elem->out_num; i++)
395 dma_memory_unmap(dma_as, elem->out_sg[i].iov_base,
396 elem->out_sg[i].iov_len,
397 DMA_DIRECTION_TO_DEVICE,
398 elem->out_sg[i].iov_len);
399 }
400
401 /* virtqueue_detach_element:
402 * @vq: The #VirtQueue
403 * @elem: The #VirtQueueElement
404 * @len: number of bytes written
405 *
406 * Detach the element from the virtqueue. This function is suitable for device
407 * reset or other situations where a #VirtQueueElement is simply freed and will
408 * not be pushed or discarded.
409 */
410 void virtqueue_detach_element(VirtQueue *vq, const VirtQueueElement *elem,
411 unsigned int len)
412 {
413 vq->inuse--;
414 virtqueue_unmap_sg(vq, elem, len);
415 }
416
417 /* virtqueue_unpop:
418 * @vq: The #VirtQueue
419 * @elem: The #VirtQueueElement
420 * @len: number of bytes written
421 *
422 * Pretend the most recent element wasn't popped from the virtqueue. The next
423 * call to virtqueue_pop() will refetch the element.
424 */
425 void virtqueue_unpop(VirtQueue *vq, const VirtQueueElement *elem,
426 unsigned int len)
427 {
428 vq->last_avail_idx--;
429 virtqueue_detach_element(vq, elem, len);
430 }
431
432 /* virtqueue_rewind:
433 * @vq: The #VirtQueue
434 * @num: Number of elements to push back
435 *
436 * Pretend that elements weren't popped from the virtqueue. The next
437 * virtqueue_pop() will refetch the oldest element.
438 *
439 * Use virtqueue_unpop() instead if you have a VirtQueueElement.
440 *
441 * Returns: true on success, false if @num is greater than the number of in use
442 * elements.
443 */
444 bool virtqueue_rewind(VirtQueue *vq, unsigned int num)
445 {
446 if (num > vq->inuse) {
447 return false;
448 }
449 vq->last_avail_idx -= num;
450 vq->inuse -= num;
451 return true;
452 }
453
454 /* Called within rcu_read_lock(). */
455 void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
456 unsigned int len, unsigned int idx)
457 {
458 VRingUsedElem uelem;
459
460 trace_virtqueue_fill(vq, elem, len, idx);
461
462 virtqueue_unmap_sg(vq, elem, len);
463
464 if (unlikely(vq->vdev->broken)) {
465 return;
466 }
467
468 if (unlikely(!vq->vring.used)) {
469 return;
470 }
471
472 idx = (idx + vq->used_idx) % vq->vring.num;
473
474 uelem.id = elem->index;
475 uelem.len = len;
476 vring_used_write(vq, &uelem, idx);
477 }
478
479 /* Called within rcu_read_lock(). */
480 void virtqueue_flush(VirtQueue *vq, unsigned int count)
481 {
482 uint16_t old, new;
483
484 if (unlikely(vq->vdev->broken)) {
485 vq->inuse -= count;
486 return;
487 }
488
489 if (unlikely(!vq->vring.used)) {
490 return;
491 }
492
493 /* Make sure buffer is written before we update index. */
494 smp_wmb();
495 trace_virtqueue_flush(vq, count);
496 old = vq->used_idx;
497 new = old + count;
498 vring_used_idx_set(vq, new);
499 vq->inuse -= count;
500 if (unlikely((int16_t)(new - vq->signalled_used) < (uint16_t)(new - old)))
501 vq->signalled_used_valid = false;
502 }
503
504 void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
505 unsigned int len)
506 {
507 rcu_read_lock();
508 virtqueue_fill(vq, elem, len, 0);
509 virtqueue_flush(vq, 1);
510 rcu_read_unlock();
511 }
512
513 /* Called within rcu_read_lock(). */
514 static int virtqueue_num_heads(VirtQueue *vq, unsigned int idx)
515 {
516 uint16_t num_heads = vring_avail_idx(vq) - idx;
517
518 /* Check it isn't doing very strange things with descriptor numbers. */
519 if (num_heads > vq->vring.num) {
520 virtio_error(vq->vdev, "Guest moved used index from %u to %u",
521 idx, vq->shadow_avail_idx);
522 return -EINVAL;
523 }
524 /* On success, callers read a descriptor at vq->last_avail_idx.
525 * Make sure descriptor read does not bypass avail index read. */
526 if (num_heads) {
527 smp_rmb();
528 }
529
530 return num_heads;
531 }
532
533 /* Called within rcu_read_lock(). */
534 static bool virtqueue_get_head(VirtQueue *vq, unsigned int idx,
535 unsigned int *head)
536 {
537 /* Grab the next descriptor number they're advertising, and increment
538 * the index we've seen. */
539 *head = vring_avail_ring(vq, idx % vq->vring.num);
540
541 /* If their number is silly, that's a fatal mistake. */
542 if (*head >= vq->vring.num) {
543 virtio_error(vq->vdev, "Guest says index %u is available", *head);
544 return false;
545 }
546
547 return true;
548 }
549
550 enum {
551 VIRTQUEUE_READ_DESC_ERROR = -1,
552 VIRTQUEUE_READ_DESC_DONE = 0, /* end of chain */
553 VIRTQUEUE_READ_DESC_MORE = 1, /* more buffers in chain */
554 };
555
556 static int virtqueue_read_next_desc(VirtIODevice *vdev, VRingDesc *desc,
557 MemoryRegionCache *desc_cache, unsigned int max,
558 unsigned int *next)
559 {
560 /* If this descriptor says it doesn't chain, we're done. */
561 if (!(desc->flags & VRING_DESC_F_NEXT)) {
562 return VIRTQUEUE_READ_DESC_DONE;
563 }
564
565 /* Check they're not leading us off end of descriptors. */
566 *next = desc->next;
567 /* Make sure compiler knows to grab that: we don't want it changing! */
568 smp_wmb();
569
570 if (*next >= max) {
571 virtio_error(vdev, "Desc next is %u", *next);
572 return VIRTQUEUE_READ_DESC_ERROR;
573 }
574
575 vring_desc_read(vdev, desc, desc_cache, *next);
576 return VIRTQUEUE_READ_DESC_MORE;
577 }
578
579 void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
580 unsigned int *out_bytes,
581 unsigned max_in_bytes, unsigned max_out_bytes)
582 {
583 VirtIODevice *vdev = vq->vdev;
584 unsigned int max, idx;
585 unsigned int total_bufs, in_total, out_total;
586 VRingMemoryRegionCaches *caches;
587 MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
588 int64_t len = 0;
589 int rc;
590
591 if (unlikely(!vq->vring.desc)) {
592 if (in_bytes) {
593 *in_bytes = 0;
594 }
595 if (out_bytes) {
596 *out_bytes = 0;
597 }
598 return;
599 }
600
601 rcu_read_lock();
602 idx = vq->last_avail_idx;
603 total_bufs = in_total = out_total = 0;
604
605 max = vq->vring.num;
606 caches = vring_get_region_caches(vq);
607 if (caches->desc.len < max * sizeof(VRingDesc)) {
608 virtio_error(vdev, "Cannot map descriptor ring");
609 goto err;
610 }
611
612 while ((rc = virtqueue_num_heads(vq, idx)) > 0) {
613 MemoryRegionCache *desc_cache = &caches->desc;
614 unsigned int num_bufs;
615 VRingDesc desc;
616 unsigned int i;
617
618 num_bufs = total_bufs;
619
620 if (!virtqueue_get_head(vq, idx++, &i)) {
621 goto err;
622 }
623
624 vring_desc_read(vdev, &desc, desc_cache, i);
625
626 if (desc.flags & VRING_DESC_F_INDIRECT) {
627 if (desc.len % sizeof(VRingDesc)) {
628 virtio_error(vdev, "Invalid size for indirect buffer table");
629 goto err;
630 }
631
632 /* If we've got too many, that implies a descriptor loop. */
633 if (num_bufs >= max) {
634 virtio_error(vdev, "Looped descriptor");
635 goto err;
636 }
637
638 /* loop over the indirect descriptor table */
639 len = address_space_cache_init(&indirect_desc_cache,
640 vdev->dma_as,
641 desc.addr, desc.len, false);
642 desc_cache = &indirect_desc_cache;
643 if (len < desc.len) {
644 virtio_error(vdev, "Cannot map indirect buffer");
645 goto err;
646 }
647
648 max = desc.len / sizeof(VRingDesc);
649 num_bufs = i = 0;
650 vring_desc_read(vdev, &desc, desc_cache, i);
651 }
652
653 do {
654 /* If we've got too many, that implies a descriptor loop. */
655 if (++num_bufs > max) {
656 virtio_error(vdev, "Looped descriptor");
657 goto err;
658 }
659
660 if (desc.flags & VRING_DESC_F_WRITE) {
661 in_total += desc.len;
662 } else {
663 out_total += desc.len;
664 }
665 if (in_total >= max_in_bytes && out_total >= max_out_bytes) {
666 goto done;
667 }
668
669 rc = virtqueue_read_next_desc(vdev, &desc, desc_cache, max, &i);
670 } while (rc == VIRTQUEUE_READ_DESC_MORE);
671
672 if (rc == VIRTQUEUE_READ_DESC_ERROR) {
673 goto err;
674 }
675
676 if (desc_cache == &indirect_desc_cache) {
677 address_space_cache_destroy(&indirect_desc_cache);
678 total_bufs++;
679 } else {
680 total_bufs = num_bufs;
681 }
682 }
683
684 if (rc < 0) {
685 goto err;
686 }
687
688 done:
689 address_space_cache_destroy(&indirect_desc_cache);
690 if (in_bytes) {
691 *in_bytes = in_total;
692 }
693 if (out_bytes) {
694 *out_bytes = out_total;
695 }
696 rcu_read_unlock();
697 return;
698
699 err:
700 in_total = out_total = 0;
701 goto done;
702 }
703
704 int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes,
705 unsigned int out_bytes)
706 {
707 unsigned int in_total, out_total;
708
709 virtqueue_get_avail_bytes(vq, &in_total, &out_total, in_bytes, out_bytes);
710 return in_bytes <= in_total && out_bytes <= out_total;
711 }
712
713 static bool virtqueue_map_desc(VirtIODevice *vdev, unsigned int *p_num_sg,
714 hwaddr *addr, struct iovec *iov,
715 unsigned int max_num_sg, bool is_write,
716 hwaddr pa, size_t sz)
717 {
718 bool ok = false;
719 unsigned num_sg = *p_num_sg;
720 assert(num_sg <= max_num_sg);
721
722 if (!sz) {
723 virtio_error(vdev, "virtio: zero sized buffers are not allowed");
724 goto out;
725 }
726
727 while (sz) {
728 hwaddr len = sz;
729
730 if (num_sg == max_num_sg) {
731 virtio_error(vdev, "virtio: too many write descriptors in "
732 "indirect table");
733 goto out;
734 }
735
736 iov[num_sg].iov_base = dma_memory_map(vdev->dma_as, pa, &len,
737 is_write ?
738 DMA_DIRECTION_FROM_DEVICE :
739 DMA_DIRECTION_TO_DEVICE);
740 if (!iov[num_sg].iov_base) {
741 virtio_error(vdev, "virtio: bogus descriptor or out of resources");
742 goto out;
743 }
744
745 iov[num_sg].iov_len = len;
746 addr[num_sg] = pa;
747
748 sz -= len;
749 pa += len;
750 num_sg++;
751 }
752 ok = true;
753
754 out:
755 *p_num_sg = num_sg;
756 return ok;
757 }
758
759 /* Only used by error code paths before we have a VirtQueueElement (therefore
760 * virtqueue_unmap_sg() can't be used). Assumes buffers weren't written to
761 * yet.
762 */
763 static void virtqueue_undo_map_desc(unsigned int out_num, unsigned int in_num,
764 struct iovec *iov)
765 {
766 unsigned int i;
767
768 for (i = 0; i < out_num + in_num; i++) {
769 int is_write = i >= out_num;
770
771 cpu_physical_memory_unmap(iov->iov_base, iov->iov_len, is_write, 0);
772 iov++;
773 }
774 }
775
776 static void virtqueue_map_iovec(VirtIODevice *vdev, struct iovec *sg,
777 hwaddr *addr, unsigned int *num_sg,
778 int is_write)
779 {
780 unsigned int i;
781 hwaddr len;
782
783 for (i = 0; i < *num_sg; i++) {
784 len = sg[i].iov_len;
785 sg[i].iov_base = dma_memory_map(vdev->dma_as,
786 addr[i], &len, is_write ?
787 DMA_DIRECTION_FROM_DEVICE :
788 DMA_DIRECTION_TO_DEVICE);
789 if (!sg[i].iov_base) {
790 error_report("virtio: error trying to map MMIO memory");
791 exit(1);
792 }
793 if (len != sg[i].iov_len) {
794 error_report("virtio: unexpected memory split");
795 exit(1);
796 }
797 }
798 }
799
800 void virtqueue_map(VirtIODevice *vdev, VirtQueueElement *elem)
801 {
802 virtqueue_map_iovec(vdev, elem->in_sg, elem->in_addr, &elem->in_num, 1);
803 virtqueue_map_iovec(vdev, elem->out_sg, elem->out_addr, &elem->out_num, 0);
804 }
805
806 static void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned in_num)
807 {
808 VirtQueueElement *elem;
809 size_t in_addr_ofs = QEMU_ALIGN_UP(sz, __alignof__(elem->in_addr[0]));
810 size_t out_addr_ofs = in_addr_ofs + in_num * sizeof(elem->in_addr[0]);
811 size_t out_addr_end = out_addr_ofs + out_num * sizeof(elem->out_addr[0]);
812 size_t in_sg_ofs = QEMU_ALIGN_UP(out_addr_end, __alignof__(elem->in_sg[0]));
813 size_t out_sg_ofs = in_sg_ofs + in_num * sizeof(elem->in_sg[0]);
814 size_t out_sg_end = out_sg_ofs + out_num * sizeof(elem->out_sg[0]);
815
816 assert(sz >= sizeof(VirtQueueElement));
817 elem = g_malloc(out_sg_end);
818 trace_virtqueue_alloc_element(elem, sz, in_num, out_num);
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 * This is just one thing (there are probably more) that must be
1029 * fixed before we can allow NDEBUG compilation.
1030 */
1031 assert(ARRAY_SIZE(data.in_addr) >= data.in_num);
1032 assert(ARRAY_SIZE(data.out_addr) >= data.out_num);
1033
1034 elem = virtqueue_alloc_element(sz, data.out_num, data.in_num);
1035 elem->index = data.index;
1036
1037 for (i = 0; i < elem->in_num; i++) {
1038 elem->in_addr[i] = data.in_addr[i];
1039 }
1040
1041 for (i = 0; i < elem->out_num; i++) {
1042 elem->out_addr[i] = data.out_addr[i];
1043 }
1044
1045 for (i = 0; i < elem->in_num; i++) {
1046 /* Base is overwritten by virtqueue_map. */
1047 elem->in_sg[i].iov_base = 0;
1048 elem->in_sg[i].iov_len = data.in_sg[i].iov_len;
1049 }
1050
1051 for (i = 0; i < elem->out_num; i++) {
1052 /* Base is overwritten by virtqueue_map. */
1053 elem->out_sg[i].iov_base = 0;
1054 elem->out_sg[i].iov_len = data.out_sg[i].iov_len;
1055 }
1056
1057 virtqueue_map(vdev, elem);
1058 return elem;
1059 }
1060
1061 void qemu_put_virtqueue_element(QEMUFile *f, VirtQueueElement *elem)
1062 {
1063 VirtQueueElementOld data;
1064 int i;
1065
1066 memset(&data, 0, sizeof(data));
1067 data.index = elem->index;
1068 data.in_num = elem->in_num;
1069 data.out_num = elem->out_num;
1070
1071 for (i = 0; i < elem->in_num; i++) {
1072 data.in_addr[i] = elem->in_addr[i];
1073 }
1074
1075 for (i = 0; i < elem->out_num; i++) {
1076 data.out_addr[i] = elem->out_addr[i];
1077 }
1078
1079 for (i = 0; i < elem->in_num; i++) {
1080 /* Base is overwritten by virtqueue_map when loading. Do not
1081 * save it, as it would leak the QEMU address space layout. */
1082 data.in_sg[i].iov_len = elem->in_sg[i].iov_len;
1083 }
1084
1085 for (i = 0; i < elem->out_num; i++) {
1086 /* Do not save iov_base as above. */
1087 data.out_sg[i].iov_len = elem->out_sg[i].iov_len;
1088 }
1089 qemu_put_buffer(f, (uint8_t *)&data, sizeof(VirtQueueElementOld));
1090 }
1091
1092 /* virtio device */
1093 static void virtio_notify_vector(VirtIODevice *vdev, uint16_t vector)
1094 {
1095 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1096 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1097
1098 if (unlikely(vdev->broken)) {
1099 return;
1100 }
1101
1102 if (k->notify) {
1103 k->notify(qbus->parent, vector);
1104 }
1105 }
1106
1107 void virtio_update_irq(VirtIODevice *vdev)
1108 {
1109 virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
1110 }
1111
1112 static int virtio_validate_features(VirtIODevice *vdev)
1113 {
1114 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1115
1116 if (virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM) &&
1117 !virtio_vdev_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM)) {
1118 return -EFAULT;
1119 }
1120
1121 if (k->validate_features) {
1122 return k->validate_features(vdev);
1123 } else {
1124 return 0;
1125 }
1126 }
1127
1128 int virtio_set_status(VirtIODevice *vdev, uint8_t val)
1129 {
1130 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1131 trace_virtio_set_status(vdev, val);
1132
1133 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
1134 if (!(vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) &&
1135 val & VIRTIO_CONFIG_S_FEATURES_OK) {
1136 int ret = virtio_validate_features(vdev);
1137
1138 if (ret) {
1139 return ret;
1140 }
1141 }
1142 }
1143 if (k->set_status) {
1144 k->set_status(vdev, val);
1145 }
1146 vdev->status = val;
1147 return 0;
1148 }
1149
1150 bool target_words_bigendian(void);
1151 static enum virtio_device_endian virtio_default_endian(void)
1152 {
1153 if (target_words_bigendian()) {
1154 return VIRTIO_DEVICE_ENDIAN_BIG;
1155 } else {
1156 return VIRTIO_DEVICE_ENDIAN_LITTLE;
1157 }
1158 }
1159
1160 static enum virtio_device_endian virtio_current_cpu_endian(void)
1161 {
1162 CPUClass *cc = CPU_GET_CLASS(current_cpu);
1163
1164 if (cc->virtio_is_big_endian(current_cpu)) {
1165 return VIRTIO_DEVICE_ENDIAN_BIG;
1166 } else {
1167 return VIRTIO_DEVICE_ENDIAN_LITTLE;
1168 }
1169 }
1170
1171 static void virtio_virtqueue_reset_region_cache(struct VirtQueue *vq)
1172 {
1173 VRingMemoryRegionCaches *caches;
1174
1175 caches = atomic_read(&vq->vring.caches);
1176 atomic_rcu_set(&vq->vring.caches, NULL);
1177 if (caches) {
1178 call_rcu(caches, virtio_free_region_cache, rcu);
1179 }
1180 }
1181
1182 void virtio_reset(void *opaque)
1183 {
1184 VirtIODevice *vdev = opaque;
1185 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1186 int i;
1187
1188 virtio_set_status(vdev, 0);
1189 if (current_cpu) {
1190 /* Guest initiated reset */
1191 vdev->device_endian = virtio_current_cpu_endian();
1192 } else {
1193 /* System reset */
1194 vdev->device_endian = virtio_default_endian();
1195 }
1196
1197 if (k->reset) {
1198 k->reset(vdev);
1199 }
1200
1201 vdev->broken = false;
1202 vdev->guest_features = 0;
1203 vdev->queue_sel = 0;
1204 vdev->status = 0;
1205 atomic_set(&vdev->isr, 0);
1206 vdev->config_vector = VIRTIO_NO_VECTOR;
1207 virtio_notify_vector(vdev, vdev->config_vector);
1208
1209 for(i = 0; i < VIRTIO_QUEUE_MAX; i++) {
1210 vdev->vq[i].vring.desc = 0;
1211 vdev->vq[i].vring.avail = 0;
1212 vdev->vq[i].vring.used = 0;
1213 vdev->vq[i].last_avail_idx = 0;
1214 vdev->vq[i].shadow_avail_idx = 0;
1215 vdev->vq[i].used_idx = 0;
1216 virtio_queue_set_vector(vdev, i, VIRTIO_NO_VECTOR);
1217 vdev->vq[i].signalled_used = 0;
1218 vdev->vq[i].signalled_used_valid = false;
1219 vdev->vq[i].notification = true;
1220 vdev->vq[i].vring.num = vdev->vq[i].vring.num_default;
1221 vdev->vq[i].inuse = 0;
1222 virtio_virtqueue_reset_region_cache(&vdev->vq[i]);
1223 }
1224 }
1225
1226 uint32_t virtio_config_readb(VirtIODevice *vdev, uint32_t addr)
1227 {
1228 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1229 uint8_t val;
1230
1231 if (addr + sizeof(val) > vdev->config_len) {
1232 return (uint32_t)-1;
1233 }
1234
1235 k->get_config(vdev, vdev->config);
1236
1237 val = ldub_p(vdev->config + addr);
1238 return val;
1239 }
1240
1241 uint32_t virtio_config_readw(VirtIODevice *vdev, uint32_t addr)
1242 {
1243 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1244 uint16_t val;
1245
1246 if (addr + sizeof(val) > vdev->config_len) {
1247 return (uint32_t)-1;
1248 }
1249
1250 k->get_config(vdev, vdev->config);
1251
1252 val = lduw_p(vdev->config + addr);
1253 return val;
1254 }
1255
1256 uint32_t virtio_config_readl(VirtIODevice *vdev, uint32_t addr)
1257 {
1258 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1259 uint32_t val;
1260
1261 if (addr + sizeof(val) > vdev->config_len) {
1262 return (uint32_t)-1;
1263 }
1264
1265 k->get_config(vdev, vdev->config);
1266
1267 val = ldl_p(vdev->config + addr);
1268 return val;
1269 }
1270
1271 void virtio_config_writeb(VirtIODevice *vdev, uint32_t addr, uint32_t data)
1272 {
1273 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1274 uint8_t val = data;
1275
1276 if (addr + sizeof(val) > vdev->config_len) {
1277 return;
1278 }
1279
1280 stb_p(vdev->config + addr, val);
1281
1282 if (k->set_config) {
1283 k->set_config(vdev, vdev->config);
1284 }
1285 }
1286
1287 void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data)
1288 {
1289 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1290 uint16_t val = data;
1291
1292 if (addr + sizeof(val) > vdev->config_len) {
1293 return;
1294 }
1295
1296 stw_p(vdev->config + addr, val);
1297
1298 if (k->set_config) {
1299 k->set_config(vdev, vdev->config);
1300 }
1301 }
1302
1303 void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data)
1304 {
1305 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1306 uint32_t val = data;
1307
1308 if (addr + sizeof(val) > vdev->config_len) {
1309 return;
1310 }
1311
1312 stl_p(vdev->config + addr, val);
1313
1314 if (k->set_config) {
1315 k->set_config(vdev, vdev->config);
1316 }
1317 }
1318
1319 uint32_t virtio_config_modern_readb(VirtIODevice *vdev, uint32_t addr)
1320 {
1321 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1322 uint8_t val;
1323
1324 if (addr + sizeof(val) > vdev->config_len) {
1325 return (uint32_t)-1;
1326 }
1327
1328 k->get_config(vdev, vdev->config);
1329
1330 val = ldub_p(vdev->config + addr);
1331 return val;
1332 }
1333
1334 uint32_t virtio_config_modern_readw(VirtIODevice *vdev, uint32_t addr)
1335 {
1336 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1337 uint16_t val;
1338
1339 if (addr + sizeof(val) > vdev->config_len) {
1340 return (uint32_t)-1;
1341 }
1342
1343 k->get_config(vdev, vdev->config);
1344
1345 val = lduw_le_p(vdev->config + addr);
1346 return val;
1347 }
1348
1349 uint32_t virtio_config_modern_readl(VirtIODevice *vdev, uint32_t addr)
1350 {
1351 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1352 uint32_t val;
1353
1354 if (addr + sizeof(val) > vdev->config_len) {
1355 return (uint32_t)-1;
1356 }
1357
1358 k->get_config(vdev, vdev->config);
1359
1360 val = ldl_le_p(vdev->config + addr);
1361 return val;
1362 }
1363
1364 void virtio_config_modern_writeb(VirtIODevice *vdev,
1365 uint32_t addr, uint32_t data)
1366 {
1367 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1368 uint8_t val = data;
1369
1370 if (addr + sizeof(val) > vdev->config_len) {
1371 return;
1372 }
1373
1374 stb_p(vdev->config + addr, val);
1375
1376 if (k->set_config) {
1377 k->set_config(vdev, vdev->config);
1378 }
1379 }
1380
1381 void virtio_config_modern_writew(VirtIODevice *vdev,
1382 uint32_t addr, uint32_t data)
1383 {
1384 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1385 uint16_t val = data;
1386
1387 if (addr + sizeof(val) > vdev->config_len) {
1388 return;
1389 }
1390
1391 stw_le_p(vdev->config + addr, val);
1392
1393 if (k->set_config) {
1394 k->set_config(vdev, vdev->config);
1395 }
1396 }
1397
1398 void virtio_config_modern_writel(VirtIODevice *vdev,
1399 uint32_t addr, uint32_t data)
1400 {
1401 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1402 uint32_t val = data;
1403
1404 if (addr + sizeof(val) > vdev->config_len) {
1405 return;
1406 }
1407
1408 stl_le_p(vdev->config + addr, val);
1409
1410 if (k->set_config) {
1411 k->set_config(vdev, vdev->config);
1412 }
1413 }
1414
1415 void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr)
1416 {
1417 vdev->vq[n].vring.desc = addr;
1418 virtio_queue_update_rings(vdev, n);
1419 }
1420
1421 hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n)
1422 {
1423 return vdev->vq[n].vring.desc;
1424 }
1425
1426 void virtio_queue_set_rings(VirtIODevice *vdev, int n, hwaddr desc,
1427 hwaddr avail, hwaddr used)
1428 {
1429 vdev->vq[n].vring.desc = desc;
1430 vdev->vq[n].vring.avail = avail;
1431 vdev->vq[n].vring.used = used;
1432 virtio_init_region_cache(vdev, n);
1433 }
1434
1435 void virtio_queue_set_num(VirtIODevice *vdev, int n, int num)
1436 {
1437 /* Don't allow guest to flip queue between existent and
1438 * nonexistent states, or to set it to an invalid size.
1439 */
1440 if (!!num != !!vdev->vq[n].vring.num ||
1441 num > VIRTQUEUE_MAX_SIZE ||
1442 num < 0) {
1443 return;
1444 }
1445 vdev->vq[n].vring.num = num;
1446 }
1447
1448 VirtQueue *virtio_vector_first_queue(VirtIODevice *vdev, uint16_t vector)
1449 {
1450 return QLIST_FIRST(&vdev->vector_queues[vector]);
1451 }
1452
1453 VirtQueue *virtio_vector_next_queue(VirtQueue *vq)
1454 {
1455 return QLIST_NEXT(vq, node);
1456 }
1457
1458 int virtio_queue_get_num(VirtIODevice *vdev, int n)
1459 {
1460 return vdev->vq[n].vring.num;
1461 }
1462
1463 int virtio_queue_get_max_num(VirtIODevice *vdev, int n)
1464 {
1465 return vdev->vq[n].vring.num_default;
1466 }
1467
1468 int virtio_get_num_queues(VirtIODevice *vdev)
1469 {
1470 int i;
1471
1472 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
1473 if (!virtio_queue_get_num(vdev, i)) {
1474 break;
1475 }
1476 }
1477
1478 return i;
1479 }
1480
1481 void virtio_queue_set_align(VirtIODevice *vdev, int n, int align)
1482 {
1483 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1484 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1485
1486 /* virtio-1 compliant devices cannot change the alignment */
1487 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
1488 error_report("tried to modify queue alignment for virtio-1 device");
1489 return;
1490 }
1491 /* Check that the transport told us it was going to do this
1492 * (so a buggy transport will immediately assert rather than
1493 * silently failing to migrate this state)
1494 */
1495 assert(k->has_variable_vring_alignment);
1496
1497 vdev->vq[n].vring.align = align;
1498 virtio_queue_update_rings(vdev, n);
1499 }
1500
1501 static bool virtio_queue_notify_aio_vq(VirtQueue *vq)
1502 {
1503 if (vq->vring.desc && vq->handle_aio_output) {
1504 VirtIODevice *vdev = vq->vdev;
1505
1506 trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
1507 return vq->handle_aio_output(vdev, vq);
1508 }
1509
1510 return false;
1511 }
1512
1513 static void virtio_queue_notify_vq(VirtQueue *vq)
1514 {
1515 if (vq->vring.desc && vq->handle_output) {
1516 VirtIODevice *vdev = vq->vdev;
1517
1518 if (unlikely(vdev->broken)) {
1519 return;
1520 }
1521
1522 trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
1523 vq->handle_output(vdev, vq);
1524 }
1525 }
1526
1527 void virtio_queue_notify(VirtIODevice *vdev, int n)
1528 {
1529 VirtQueue *vq = &vdev->vq[n];
1530
1531 if (unlikely(!vq->vring.desc || vdev->broken)) {
1532 return;
1533 }
1534
1535 trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
1536 if (vq->handle_aio_output) {
1537 event_notifier_set(&vq->host_notifier);
1538 } else if (vq->handle_output) {
1539 vq->handle_output(vdev, vq);
1540 }
1541 }
1542
1543 uint16_t virtio_queue_vector(VirtIODevice *vdev, int n)
1544 {
1545 return n < VIRTIO_QUEUE_MAX ? vdev->vq[n].vector :
1546 VIRTIO_NO_VECTOR;
1547 }
1548
1549 void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector)
1550 {
1551 VirtQueue *vq = &vdev->vq[n];
1552
1553 if (n < VIRTIO_QUEUE_MAX) {
1554 if (vdev->vector_queues &&
1555 vdev->vq[n].vector != VIRTIO_NO_VECTOR) {
1556 QLIST_REMOVE(vq, node);
1557 }
1558 vdev->vq[n].vector = vector;
1559 if (vdev->vector_queues &&
1560 vector != VIRTIO_NO_VECTOR) {
1561 QLIST_INSERT_HEAD(&vdev->vector_queues[vector], vq, node);
1562 }
1563 }
1564 }
1565
1566 VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,
1567 VirtIOHandleOutput handle_output)
1568 {
1569 int i;
1570
1571 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
1572 if (vdev->vq[i].vring.num == 0)
1573 break;
1574 }
1575
1576 if (i == VIRTIO_QUEUE_MAX || queue_size > VIRTQUEUE_MAX_SIZE)
1577 abort();
1578
1579 vdev->vq[i].vring.num = queue_size;
1580 vdev->vq[i].vring.num_default = queue_size;
1581 vdev->vq[i].vring.align = VIRTIO_PCI_VRING_ALIGN;
1582 vdev->vq[i].handle_output = handle_output;
1583 vdev->vq[i].handle_aio_output = NULL;
1584
1585 return &vdev->vq[i];
1586 }
1587
1588 void virtio_del_queue(VirtIODevice *vdev, int n)
1589 {
1590 if (n < 0 || n >= VIRTIO_QUEUE_MAX) {
1591 abort();
1592 }
1593
1594 vdev->vq[n].vring.num = 0;
1595 vdev->vq[n].vring.num_default = 0;
1596 }
1597
1598 static void virtio_set_isr(VirtIODevice *vdev, int value)
1599 {
1600 uint8_t old = atomic_read(&vdev->isr);
1601
1602 /* Do not write ISR if it does not change, so that its cacheline remains
1603 * shared in the common case where the guest does not read it.
1604 */
1605 if ((old & value) != value) {
1606 atomic_or(&vdev->isr, value);
1607 }
1608 }
1609
1610 /* Called within rcu_read_lock(). */
1611 static bool virtio_should_notify(VirtIODevice *vdev, VirtQueue *vq)
1612 {
1613 uint16_t old, new;
1614 bool v;
1615 /* We need to expose used array entries before checking used event. */
1616 smp_mb();
1617 /* Always notify when queue is empty (when feature acknowledge) */
1618 if (virtio_vdev_has_feature(vdev, VIRTIO_F_NOTIFY_ON_EMPTY) &&
1619 !vq->inuse && virtio_queue_empty(vq)) {
1620 return true;
1621 }
1622
1623 if (!virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
1624 return !(vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT);
1625 }
1626
1627 v = vq->signalled_used_valid;
1628 vq->signalled_used_valid = true;
1629 old = vq->signalled_used;
1630 new = vq->signalled_used = vq->used_idx;
1631 return !v || vring_need_event(vring_get_used_event(vq), new, old);
1632 }
1633
1634 void virtio_notify_irqfd(VirtIODevice *vdev, VirtQueue *vq)
1635 {
1636 bool should_notify;
1637 rcu_read_lock();
1638 should_notify = virtio_should_notify(vdev, vq);
1639 rcu_read_unlock();
1640
1641 if (!should_notify) {
1642 return;
1643 }
1644
1645 trace_virtio_notify_irqfd(vdev, vq);
1646
1647 /*
1648 * virtio spec 1.0 says ISR bit 0 should be ignored with MSI, but
1649 * windows drivers included in virtio-win 1.8.0 (circa 2015) are
1650 * incorrectly polling this bit during crashdump and hibernation
1651 * in MSI mode, causing a hang if this bit is never updated.
1652 * Recent releases of Windows do not really shut down, but rather
1653 * log out and hibernate to make the next startup faster. Hence,
1654 * this manifested as a more serious hang during shutdown with
1655 *
1656 * Next driver release from 2016 fixed this problem, so working around it
1657 * is not a must, but it's easy to do so let's do it here.
1658 *
1659 * Note: it's safe to update ISR from any thread as it was switched
1660 * to an atomic operation.
1661 */
1662 virtio_set_isr(vq->vdev, 0x1);
1663 event_notifier_set(&vq->guest_notifier);
1664 }
1665
1666 static void virtio_irq(VirtQueue *vq)
1667 {
1668 virtio_set_isr(vq->vdev, 0x1);
1669 virtio_notify_vector(vq->vdev, vq->vector);
1670 }
1671
1672 void virtio_notify(VirtIODevice *vdev, VirtQueue *vq)
1673 {
1674 bool should_notify;
1675 rcu_read_lock();
1676 should_notify = virtio_should_notify(vdev, vq);
1677 rcu_read_unlock();
1678
1679 if (!should_notify) {
1680 return;
1681 }
1682
1683 trace_virtio_notify(vdev, vq);
1684 virtio_irq(vq);
1685 }
1686
1687 void virtio_notify_config(VirtIODevice *vdev)
1688 {
1689 if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK))
1690 return;
1691
1692 virtio_set_isr(vdev, 0x3);
1693 vdev->generation++;
1694 virtio_notify_vector(vdev, vdev->config_vector);
1695 }
1696
1697 static bool virtio_device_endian_needed(void *opaque)
1698 {
1699 VirtIODevice *vdev = opaque;
1700
1701 assert(vdev->device_endian != VIRTIO_DEVICE_ENDIAN_UNKNOWN);
1702 if (!virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
1703 return vdev->device_endian != virtio_default_endian();
1704 }
1705 /* Devices conforming to VIRTIO 1.0 or later are always LE. */
1706 return vdev->device_endian != VIRTIO_DEVICE_ENDIAN_LITTLE;
1707 }
1708
1709 static bool virtio_64bit_features_needed(void *opaque)
1710 {
1711 VirtIODevice *vdev = opaque;
1712
1713 return (vdev->host_features >> 32) != 0;
1714 }
1715
1716 static bool virtio_virtqueue_needed(void *opaque)
1717 {
1718 VirtIODevice *vdev = opaque;
1719
1720 return virtio_host_has_feature(vdev, VIRTIO_F_VERSION_1);
1721 }
1722
1723 static bool virtio_ringsize_needed(void *opaque)
1724 {
1725 VirtIODevice *vdev = opaque;
1726 int i;
1727
1728 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
1729 if (vdev->vq[i].vring.num != vdev->vq[i].vring.num_default) {
1730 return true;
1731 }
1732 }
1733 return false;
1734 }
1735
1736 static bool virtio_extra_state_needed(void *opaque)
1737 {
1738 VirtIODevice *vdev = opaque;
1739 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1740 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1741
1742 return k->has_extra_state &&
1743 k->has_extra_state(qbus->parent);
1744 }
1745
1746 static bool virtio_broken_needed(void *opaque)
1747 {
1748 VirtIODevice *vdev = opaque;
1749
1750 return vdev->broken;
1751 }
1752
1753 static const VMStateDescription vmstate_virtqueue = {
1754 .name = "virtqueue_state",
1755 .version_id = 1,
1756 .minimum_version_id = 1,
1757 .fields = (VMStateField[]) {
1758 VMSTATE_UINT64(vring.avail, struct VirtQueue),
1759 VMSTATE_UINT64(vring.used, struct VirtQueue),
1760 VMSTATE_END_OF_LIST()
1761 }
1762 };
1763
1764 static const VMStateDescription vmstate_virtio_virtqueues = {
1765 .name = "virtio/virtqueues",
1766 .version_id = 1,
1767 .minimum_version_id = 1,
1768 .needed = &virtio_virtqueue_needed,
1769 .fields = (VMStateField[]) {
1770 VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice,
1771 VIRTIO_QUEUE_MAX, 0, vmstate_virtqueue, VirtQueue),
1772 VMSTATE_END_OF_LIST()
1773 }
1774 };
1775
1776 static const VMStateDescription vmstate_ringsize = {
1777 .name = "ringsize_state",
1778 .version_id = 1,
1779 .minimum_version_id = 1,
1780 .fields = (VMStateField[]) {
1781 VMSTATE_UINT32(vring.num_default, struct VirtQueue),
1782 VMSTATE_END_OF_LIST()
1783 }
1784 };
1785
1786 static const VMStateDescription vmstate_virtio_ringsize = {
1787 .name = "virtio/ringsize",
1788 .version_id = 1,
1789 .minimum_version_id = 1,
1790 .needed = &virtio_ringsize_needed,
1791 .fields = (VMStateField[]) {
1792 VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice,
1793 VIRTIO_QUEUE_MAX, 0, vmstate_ringsize, VirtQueue),
1794 VMSTATE_END_OF_LIST()
1795 }
1796 };
1797
1798 static int get_extra_state(QEMUFile *f, void *pv, size_t size,
1799 VMStateField *field)
1800 {
1801 VirtIODevice *vdev = pv;
1802 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1803 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1804
1805 if (!k->load_extra_state) {
1806 return -1;
1807 } else {
1808 return k->load_extra_state(qbus->parent, f);
1809 }
1810 }
1811
1812 static int put_extra_state(QEMUFile *f, void *pv, size_t size,
1813 VMStateField *field, QJSON *vmdesc)
1814 {
1815 VirtIODevice *vdev = pv;
1816 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1817 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1818
1819 k->save_extra_state(qbus->parent, f);
1820 return 0;
1821 }
1822
1823 static const VMStateInfo vmstate_info_extra_state = {
1824 .name = "virtqueue_extra_state",
1825 .get = get_extra_state,
1826 .put = put_extra_state,
1827 };
1828
1829 static const VMStateDescription vmstate_virtio_extra_state = {
1830 .name = "virtio/extra_state",
1831 .version_id = 1,
1832 .minimum_version_id = 1,
1833 .needed = &virtio_extra_state_needed,
1834 .fields = (VMStateField[]) {
1835 {
1836 .name = "extra_state",
1837 .version_id = 0,
1838 .field_exists = NULL,
1839 .size = 0,
1840 .info = &vmstate_info_extra_state,
1841 .flags = VMS_SINGLE,
1842 .offset = 0,
1843 },
1844 VMSTATE_END_OF_LIST()
1845 }
1846 };
1847
1848 static const VMStateDescription vmstate_virtio_device_endian = {
1849 .name = "virtio/device_endian",
1850 .version_id = 1,
1851 .minimum_version_id = 1,
1852 .needed = &virtio_device_endian_needed,
1853 .fields = (VMStateField[]) {
1854 VMSTATE_UINT8(device_endian, VirtIODevice),
1855 VMSTATE_END_OF_LIST()
1856 }
1857 };
1858
1859 static const VMStateDescription vmstate_virtio_64bit_features = {
1860 .name = "virtio/64bit_features",
1861 .version_id = 1,
1862 .minimum_version_id = 1,
1863 .needed = &virtio_64bit_features_needed,
1864 .fields = (VMStateField[]) {
1865 VMSTATE_UINT64(guest_features, VirtIODevice),
1866 VMSTATE_END_OF_LIST()
1867 }
1868 };
1869
1870 static const VMStateDescription vmstate_virtio_broken = {
1871 .name = "virtio/broken",
1872 .version_id = 1,
1873 .minimum_version_id = 1,
1874 .needed = &virtio_broken_needed,
1875 .fields = (VMStateField[]) {
1876 VMSTATE_BOOL(broken, VirtIODevice),
1877 VMSTATE_END_OF_LIST()
1878 }
1879 };
1880
1881 static const VMStateDescription vmstate_virtio = {
1882 .name = "virtio",
1883 .version_id = 1,
1884 .minimum_version_id = 1,
1885 .minimum_version_id_old = 1,
1886 .fields = (VMStateField[]) {
1887 VMSTATE_END_OF_LIST()
1888 },
1889 .subsections = (const VMStateDescription*[]) {
1890 &vmstate_virtio_device_endian,
1891 &vmstate_virtio_64bit_features,
1892 &vmstate_virtio_virtqueues,
1893 &vmstate_virtio_ringsize,
1894 &vmstate_virtio_broken,
1895 &vmstate_virtio_extra_state,
1896 NULL
1897 }
1898 };
1899
1900 void virtio_save(VirtIODevice *vdev, QEMUFile *f)
1901 {
1902 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1903 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1904 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
1905 uint32_t guest_features_lo = (vdev->guest_features & 0xffffffff);
1906 int i;
1907
1908 if (k->save_config) {
1909 k->save_config(qbus->parent, f);
1910 }
1911
1912 qemu_put_8s(f, &vdev->status);
1913 qemu_put_8s(f, &vdev->isr);
1914 qemu_put_be16s(f, &vdev->queue_sel);
1915 qemu_put_be32s(f, &guest_features_lo);
1916 qemu_put_be32(f, vdev->config_len);
1917 qemu_put_buffer(f, vdev->config, vdev->config_len);
1918
1919 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
1920 if (vdev->vq[i].vring.num == 0)
1921 break;
1922 }
1923
1924 qemu_put_be32(f, i);
1925
1926 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
1927 if (vdev->vq[i].vring.num == 0)
1928 break;
1929
1930 qemu_put_be32(f, vdev->vq[i].vring.num);
1931 if (k->has_variable_vring_alignment) {
1932 qemu_put_be32(f, vdev->vq[i].vring.align);
1933 }
1934 /*
1935 * Save desc now, the rest of the ring addresses are saved in
1936 * subsections for VIRTIO-1 devices.
1937 */
1938 qemu_put_be64(f, vdev->vq[i].vring.desc);
1939 qemu_put_be16s(f, &vdev->vq[i].last_avail_idx);
1940 if (k->save_queue) {
1941 k->save_queue(qbus->parent, i, f);
1942 }
1943 }
1944
1945 if (vdc->save != NULL) {
1946 vdc->save(vdev, f);
1947 }
1948
1949 if (vdc->vmsd) {
1950 vmstate_save_state(f, vdc->vmsd, vdev, NULL);
1951 }
1952
1953 /* Subsections */
1954 vmstate_save_state(f, &vmstate_virtio, vdev, NULL);
1955 }
1956
1957 /* A wrapper for use as a VMState .put function */
1958 static int virtio_device_put(QEMUFile *f, void *opaque, size_t size,
1959 VMStateField *field, QJSON *vmdesc)
1960 {
1961 virtio_save(VIRTIO_DEVICE(opaque), f);
1962
1963 return 0;
1964 }
1965
1966 /* A wrapper for use as a VMState .get function */
1967 static int virtio_device_get(QEMUFile *f, void *opaque, size_t size,
1968 VMStateField *field)
1969 {
1970 VirtIODevice *vdev = VIRTIO_DEVICE(opaque);
1971 DeviceClass *dc = DEVICE_CLASS(VIRTIO_DEVICE_GET_CLASS(vdev));
1972
1973 return virtio_load(vdev, f, dc->vmsd->version_id);
1974 }
1975
1976 const VMStateInfo virtio_vmstate_info = {
1977 .name = "virtio",
1978 .get = virtio_device_get,
1979 .put = virtio_device_put,
1980 };
1981
1982 static int virtio_set_features_nocheck(VirtIODevice *vdev, uint64_t val)
1983 {
1984 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1985 bool bad = (val & ~(vdev->host_features)) != 0;
1986
1987 val &= vdev->host_features;
1988 if (k->set_features) {
1989 k->set_features(vdev, val);
1990 }
1991 vdev->guest_features = val;
1992 return bad ? -1 : 0;
1993 }
1994
1995 int virtio_set_features(VirtIODevice *vdev, uint64_t val)
1996 {
1997 /*
1998 * The driver must not attempt to set features after feature negotiation
1999 * has finished.
2000 */
2001 if (vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) {
2002 return -EINVAL;
2003 }
2004 return virtio_set_features_nocheck(vdev, val);
2005 }
2006
2007 int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id)
2008 {
2009 int i, ret;
2010 int32_t config_len;
2011 uint32_t num;
2012 uint32_t features;
2013 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2014 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2015 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
2016
2017 /*
2018 * We poison the endianness to ensure it does not get used before
2019 * subsections have been loaded.
2020 */
2021 vdev->device_endian = VIRTIO_DEVICE_ENDIAN_UNKNOWN;
2022
2023 if (k->load_config) {
2024 ret = k->load_config(qbus->parent, f);
2025 if (ret)
2026 return ret;
2027 }
2028
2029 qemu_get_8s(f, &vdev->status);
2030 qemu_get_8s(f, &vdev->isr);
2031 qemu_get_be16s(f, &vdev->queue_sel);
2032 if (vdev->queue_sel >= VIRTIO_QUEUE_MAX) {
2033 return -1;
2034 }
2035 qemu_get_be32s(f, &features);
2036
2037 /*
2038 * Temporarily set guest_features low bits - needed by
2039 * virtio net load code testing for VIRTIO_NET_F_CTRL_GUEST_OFFLOADS
2040 * VIRTIO_NET_F_GUEST_ANNOUNCE and VIRTIO_NET_F_CTRL_VQ.
2041 *
2042 * Note: devices should always test host features in future - don't create
2043 * new dependencies like this.
2044 */
2045 vdev->guest_features = features;
2046
2047 config_len = qemu_get_be32(f);
2048
2049 /*
2050 * There are cases where the incoming config can be bigger or smaller
2051 * than what we have; so load what we have space for, and skip
2052 * any excess that's in the stream.
2053 */
2054 qemu_get_buffer(f, vdev->config, MIN(config_len, vdev->config_len));
2055
2056 while (config_len > vdev->config_len) {
2057 qemu_get_byte(f);
2058 config_len--;
2059 }
2060
2061 num = qemu_get_be32(f);
2062
2063 if (num > VIRTIO_QUEUE_MAX) {
2064 error_report("Invalid number of virtqueues: 0x%x", num);
2065 return -1;
2066 }
2067
2068 for (i = 0; i < num; i++) {
2069 vdev->vq[i].vring.num = qemu_get_be32(f);
2070 if (k->has_variable_vring_alignment) {
2071 vdev->vq[i].vring.align = qemu_get_be32(f);
2072 }
2073 vdev->vq[i].vring.desc = qemu_get_be64(f);
2074 qemu_get_be16s(f, &vdev->vq[i].last_avail_idx);
2075 vdev->vq[i].signalled_used_valid = false;
2076 vdev->vq[i].notification = true;
2077
2078 if (!vdev->vq[i].vring.desc && vdev->vq[i].last_avail_idx) {
2079 error_report("VQ %d address 0x0 "
2080 "inconsistent with Host index 0x%x",
2081 i, vdev->vq[i].last_avail_idx);
2082 return -1;
2083 }
2084 if (k->load_queue) {
2085 ret = k->load_queue(qbus->parent, i, f);
2086 if (ret)
2087 return ret;
2088 }
2089 }
2090
2091 virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
2092
2093 if (vdc->load != NULL) {
2094 ret = vdc->load(vdev, f, version_id);
2095 if (ret) {
2096 return ret;
2097 }
2098 }
2099
2100 if (vdc->vmsd) {
2101 ret = vmstate_load_state(f, vdc->vmsd, vdev, version_id);
2102 if (ret) {
2103 return ret;
2104 }
2105 }
2106
2107 /* Subsections */
2108 ret = vmstate_load_state(f, &vmstate_virtio, vdev, 1);
2109 if (ret) {
2110 return ret;
2111 }
2112
2113 if (vdev->device_endian == VIRTIO_DEVICE_ENDIAN_UNKNOWN) {
2114 vdev->device_endian = virtio_default_endian();
2115 }
2116
2117 if (virtio_64bit_features_needed(vdev)) {
2118 /*
2119 * Subsection load filled vdev->guest_features. Run them
2120 * through virtio_set_features to sanity-check them against
2121 * host_features.
2122 */
2123 uint64_t features64 = vdev->guest_features;
2124 if (virtio_set_features_nocheck(vdev, features64) < 0) {
2125 error_report("Features 0x%" PRIx64 " unsupported. "
2126 "Allowed features: 0x%" PRIx64,
2127 features64, vdev->host_features);
2128 return -1;
2129 }
2130 } else {
2131 if (virtio_set_features_nocheck(vdev, features) < 0) {
2132 error_report("Features 0x%x unsupported. "
2133 "Allowed features: 0x%" PRIx64,
2134 features, vdev->host_features);
2135 return -1;
2136 }
2137 }
2138
2139 rcu_read_lock();
2140 for (i = 0; i < num; i++) {
2141 if (vdev->vq[i].vring.desc) {
2142 uint16_t nheads;
2143
2144 /*
2145 * VIRTIO-1 devices migrate desc, used, and avail ring addresses so
2146 * only the region cache needs to be set up. Legacy devices need
2147 * to calculate used and avail ring addresses based on the desc
2148 * address.
2149 */
2150 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
2151 virtio_init_region_cache(vdev, i);
2152 } else {
2153 virtio_queue_update_rings(vdev, i);
2154 }
2155
2156 nheads = vring_avail_idx(&vdev->vq[i]) - vdev->vq[i].last_avail_idx;
2157 /* Check it isn't doing strange things with descriptor numbers. */
2158 if (nheads > vdev->vq[i].vring.num) {
2159 error_report("VQ %d size 0x%x Guest index 0x%x "
2160 "inconsistent with Host index 0x%x: delta 0x%x",
2161 i, vdev->vq[i].vring.num,
2162 vring_avail_idx(&vdev->vq[i]),
2163 vdev->vq[i].last_avail_idx, nheads);
2164 return -1;
2165 }
2166 vdev->vq[i].used_idx = vring_used_idx(&vdev->vq[i]);
2167 vdev->vq[i].shadow_avail_idx = vring_avail_idx(&vdev->vq[i]);
2168
2169 /*
2170 * Some devices migrate VirtQueueElements that have been popped
2171 * from the avail ring but not yet returned to the used ring.
2172 * Since max ring size < UINT16_MAX it's safe to use modulo
2173 * UINT16_MAX + 1 subtraction.
2174 */
2175 vdev->vq[i].inuse = (uint16_t)(vdev->vq[i].last_avail_idx -
2176 vdev->vq[i].used_idx);
2177 if (vdev->vq[i].inuse > vdev->vq[i].vring.num) {
2178 error_report("VQ %d size 0x%x < last_avail_idx 0x%x - "
2179 "used_idx 0x%x",
2180 i, vdev->vq[i].vring.num,
2181 vdev->vq[i].last_avail_idx,
2182 vdev->vq[i].used_idx);
2183 return -1;
2184 }
2185 }
2186 }
2187 rcu_read_unlock();
2188
2189 return 0;
2190 }
2191
2192 void virtio_cleanup(VirtIODevice *vdev)
2193 {
2194 qemu_del_vm_change_state_handler(vdev->vmstate);
2195 }
2196
2197 static void virtio_vmstate_change(void *opaque, int running, RunState state)
2198 {
2199 VirtIODevice *vdev = opaque;
2200 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2201 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2202 bool backend_run = running && (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK);
2203 vdev->vm_running = running;
2204
2205 if (backend_run) {
2206 virtio_set_status(vdev, vdev->status);
2207 }
2208
2209 if (k->vmstate_change) {
2210 k->vmstate_change(qbus->parent, backend_run);
2211 }
2212
2213 if (!backend_run) {
2214 virtio_set_status(vdev, vdev->status);
2215 }
2216 }
2217
2218 void virtio_instance_init_common(Object *proxy_obj, void *data,
2219 size_t vdev_size, const char *vdev_name)
2220 {
2221 DeviceState *vdev = data;
2222
2223 object_initialize(vdev, vdev_size, vdev_name);
2224 object_property_add_child(proxy_obj, "virtio-backend", OBJECT(vdev), NULL);
2225 object_unref(OBJECT(vdev));
2226 qdev_alias_all_properties(vdev, proxy_obj);
2227 }
2228
2229 void virtio_init(VirtIODevice *vdev, const char *name,
2230 uint16_t device_id, size_t config_size)
2231 {
2232 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2233 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2234 int i;
2235 int nvectors = k->query_nvectors ? k->query_nvectors(qbus->parent) : 0;
2236
2237 if (nvectors) {
2238 vdev->vector_queues =
2239 g_malloc0(sizeof(*vdev->vector_queues) * nvectors);
2240 }
2241
2242 vdev->device_id = device_id;
2243 vdev->status = 0;
2244 atomic_set(&vdev->isr, 0);
2245 vdev->queue_sel = 0;
2246 vdev->config_vector = VIRTIO_NO_VECTOR;
2247 vdev->vq = g_malloc0(sizeof(VirtQueue) * VIRTIO_QUEUE_MAX);
2248 vdev->vm_running = runstate_is_running();
2249 vdev->broken = false;
2250 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2251 vdev->vq[i].vector = VIRTIO_NO_VECTOR;
2252 vdev->vq[i].vdev = vdev;
2253 vdev->vq[i].queue_index = i;
2254 }
2255
2256 vdev->name = name;
2257 vdev->config_len = config_size;
2258 if (vdev->config_len) {
2259 vdev->config = g_malloc0(config_size);
2260 } else {
2261 vdev->config = NULL;
2262 }
2263 vdev->vmstate = qemu_add_vm_change_state_handler(virtio_vmstate_change,
2264 vdev);
2265 vdev->device_endian = virtio_default_endian();
2266 vdev->use_guest_notifier_mask = true;
2267 }
2268
2269 hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n)
2270 {
2271 return vdev->vq[n].vring.desc;
2272 }
2273
2274 hwaddr virtio_queue_get_avail_addr(VirtIODevice *vdev, int n)
2275 {
2276 return vdev->vq[n].vring.avail;
2277 }
2278
2279 hwaddr virtio_queue_get_used_addr(VirtIODevice *vdev, int n)
2280 {
2281 return vdev->vq[n].vring.used;
2282 }
2283
2284 hwaddr virtio_queue_get_desc_size(VirtIODevice *vdev, int n)
2285 {
2286 return sizeof(VRingDesc) * vdev->vq[n].vring.num;
2287 }
2288
2289 hwaddr virtio_queue_get_avail_size(VirtIODevice *vdev, int n)
2290 {
2291 return offsetof(VRingAvail, ring) +
2292 sizeof(uint16_t) * vdev->vq[n].vring.num;
2293 }
2294
2295 hwaddr virtio_queue_get_used_size(VirtIODevice *vdev, int n)
2296 {
2297 return offsetof(VRingUsed, ring) +
2298 sizeof(VRingUsedElem) * vdev->vq[n].vring.num;
2299 }
2300
2301 uint16_t virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n)
2302 {
2303 return vdev->vq[n].last_avail_idx;
2304 }
2305
2306 void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t idx)
2307 {
2308 vdev->vq[n].last_avail_idx = idx;
2309 vdev->vq[n].shadow_avail_idx = idx;
2310 }
2311
2312 void virtio_queue_update_used_idx(VirtIODevice *vdev, int n)
2313 {
2314 rcu_read_lock();
2315 if (vdev->vq[n].vring.desc) {
2316 vdev->vq[n].used_idx = vring_used_idx(&vdev->vq[n]);
2317 }
2318 rcu_read_unlock();
2319 }
2320
2321 void virtio_queue_invalidate_signalled_used(VirtIODevice *vdev, int n)
2322 {
2323 vdev->vq[n].signalled_used_valid = false;
2324 }
2325
2326 VirtQueue *virtio_get_queue(VirtIODevice *vdev, int n)
2327 {
2328 return vdev->vq + n;
2329 }
2330
2331 uint16_t virtio_get_queue_index(VirtQueue *vq)
2332 {
2333 return vq->queue_index;
2334 }
2335
2336 static void virtio_queue_guest_notifier_read(EventNotifier *n)
2337 {
2338 VirtQueue *vq = container_of(n, VirtQueue, guest_notifier);
2339 if (event_notifier_test_and_clear(n)) {
2340 virtio_irq(vq);
2341 }
2342 }
2343
2344 void virtio_queue_set_guest_notifier_fd_handler(VirtQueue *vq, bool assign,
2345 bool with_irqfd)
2346 {
2347 if (assign && !with_irqfd) {
2348 event_notifier_set_handler(&vq->guest_notifier,
2349 virtio_queue_guest_notifier_read);
2350 } else {
2351 event_notifier_set_handler(&vq->guest_notifier, NULL);
2352 }
2353 if (!assign) {
2354 /* Test and clear notifier before closing it,
2355 * in case poll callback didn't have time to run. */
2356 virtio_queue_guest_notifier_read(&vq->guest_notifier);
2357 }
2358 }
2359
2360 EventNotifier *virtio_queue_get_guest_notifier(VirtQueue *vq)
2361 {
2362 return &vq->guest_notifier;
2363 }
2364
2365 static void virtio_queue_host_notifier_aio_read(EventNotifier *n)
2366 {
2367 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
2368 if (event_notifier_test_and_clear(n)) {
2369 virtio_queue_notify_aio_vq(vq);
2370 }
2371 }
2372
2373 static void virtio_queue_host_notifier_aio_poll_begin(EventNotifier *n)
2374 {
2375 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
2376
2377 virtio_queue_set_notification(vq, 0);
2378 }
2379
2380 static bool virtio_queue_host_notifier_aio_poll(void *opaque)
2381 {
2382 EventNotifier *n = opaque;
2383 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
2384 bool progress;
2385
2386 if (!vq->vring.desc || virtio_queue_empty(vq)) {
2387 return false;
2388 }
2389
2390 progress = virtio_queue_notify_aio_vq(vq);
2391
2392 /* In case the handler function re-enabled notifications */
2393 virtio_queue_set_notification(vq, 0);
2394 return progress;
2395 }
2396
2397 static void virtio_queue_host_notifier_aio_poll_end(EventNotifier *n)
2398 {
2399 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
2400
2401 /* Caller polls once more after this to catch requests that race with us */
2402 virtio_queue_set_notification(vq, 1);
2403 }
2404
2405 void virtio_queue_aio_set_host_notifier_handler(VirtQueue *vq, AioContext *ctx,
2406 VirtIOHandleAIOOutput handle_output)
2407 {
2408 if (handle_output) {
2409 vq->handle_aio_output = handle_output;
2410 aio_set_event_notifier(ctx, &vq->host_notifier, true,
2411 virtio_queue_host_notifier_aio_read,
2412 virtio_queue_host_notifier_aio_poll);
2413 aio_set_event_notifier_poll(ctx, &vq->host_notifier,
2414 virtio_queue_host_notifier_aio_poll_begin,
2415 virtio_queue_host_notifier_aio_poll_end);
2416 } else {
2417 aio_set_event_notifier(ctx, &vq->host_notifier, true, NULL, NULL);
2418 /* Test and clear notifier before after disabling event,
2419 * in case poll callback didn't have time to run. */
2420 virtio_queue_host_notifier_aio_read(&vq->host_notifier);
2421 vq->handle_aio_output = NULL;
2422 }
2423 }
2424
2425 void virtio_queue_host_notifier_read(EventNotifier *n)
2426 {
2427 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
2428 if (event_notifier_test_and_clear(n)) {
2429 virtio_queue_notify_vq(vq);
2430 }
2431 }
2432
2433 EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq)
2434 {
2435 return &vq->host_notifier;
2436 }
2437
2438 void virtio_device_set_child_bus_name(VirtIODevice *vdev, char *bus_name)
2439 {
2440 g_free(vdev->bus_name);
2441 vdev->bus_name = g_strdup(bus_name);
2442 }
2443
2444 void GCC_FMT_ATTR(2, 3) virtio_error(VirtIODevice *vdev, const char *fmt, ...)
2445 {
2446 va_list ap;
2447
2448 va_start(ap, fmt);
2449 error_vreport(fmt, ap);
2450 va_end(ap);
2451
2452 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
2453 virtio_set_status(vdev, vdev->status | VIRTIO_CONFIG_S_NEEDS_RESET);
2454 virtio_notify_config(vdev);
2455 }
2456
2457 vdev->broken = true;
2458 }
2459
2460 static void virtio_memory_listener_commit(MemoryListener *listener)
2461 {
2462 VirtIODevice *vdev = container_of(listener, VirtIODevice, listener);
2463 int i;
2464
2465 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2466 if (vdev->vq[i].vring.num == 0) {
2467 break;
2468 }
2469 virtio_init_region_cache(vdev, i);
2470 }
2471 }
2472
2473 static void virtio_device_realize(DeviceState *dev, Error **errp)
2474 {
2475 VirtIODevice *vdev = VIRTIO_DEVICE(dev);
2476 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev);
2477 Error *err = NULL;
2478
2479 /* Devices should either use vmsd or the load/save methods */
2480 assert(!vdc->vmsd || !vdc->load);
2481
2482 if (vdc->realize != NULL) {
2483 vdc->realize(dev, &err);
2484 if (err != NULL) {
2485 error_propagate(errp, err);
2486 return;
2487 }
2488 }
2489
2490 virtio_bus_device_plugged(vdev, &err);
2491 if (err != NULL) {
2492 error_propagate(errp, err);
2493 return;
2494 }
2495
2496 vdev->listener.commit = virtio_memory_listener_commit;
2497 memory_listener_register(&vdev->listener, vdev->dma_as);
2498 }
2499
2500 static void virtio_device_unrealize(DeviceState *dev, Error **errp)
2501 {
2502 VirtIODevice *vdev = VIRTIO_DEVICE(dev);
2503 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev);
2504 Error *err = NULL;
2505
2506 virtio_bus_device_unplugged(vdev);
2507
2508 if (vdc->unrealize != NULL) {
2509 vdc->unrealize(dev, &err);
2510 if (err != NULL) {
2511 error_propagate(errp, err);
2512 return;
2513 }
2514 }
2515
2516 g_free(vdev->bus_name);
2517 vdev->bus_name = NULL;
2518 }
2519
2520 static void virtio_device_free_virtqueues(VirtIODevice *vdev)
2521 {
2522 int i;
2523 if (!vdev->vq) {
2524 return;
2525 }
2526
2527 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2528 if (vdev->vq[i].vring.num == 0) {
2529 break;
2530 }
2531 virtio_virtqueue_reset_region_cache(&vdev->vq[i]);
2532 }
2533 g_free(vdev->vq);
2534 }
2535
2536 static void virtio_device_instance_finalize(Object *obj)
2537 {
2538 VirtIODevice *vdev = VIRTIO_DEVICE(obj);
2539
2540 memory_listener_unregister(&vdev->listener);
2541 virtio_device_free_virtqueues(vdev);
2542
2543 g_free(vdev->config);
2544 g_free(vdev->vector_queues);
2545 }
2546
2547 static Property virtio_properties[] = {
2548 DEFINE_VIRTIO_COMMON_FEATURES(VirtIODevice, host_features),
2549 DEFINE_PROP_END_OF_LIST(),
2550 };
2551
2552 static int virtio_device_start_ioeventfd_impl(VirtIODevice *vdev)
2553 {
2554 VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev)));
2555 int n, r, err;
2556
2557 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
2558 VirtQueue *vq = &vdev->vq[n];
2559 if (!virtio_queue_get_num(vdev, n)) {
2560 continue;
2561 }
2562 r = virtio_bus_set_host_notifier(qbus, n, true);
2563 if (r < 0) {
2564 err = r;
2565 goto assign_error;
2566 }
2567 event_notifier_set_handler(&vq->host_notifier,
2568 virtio_queue_host_notifier_read);
2569 }
2570
2571 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
2572 /* Kick right away to begin processing requests already in vring */
2573 VirtQueue *vq = &vdev->vq[n];
2574 if (!vq->vring.num) {
2575 continue;
2576 }
2577 event_notifier_set(&vq->host_notifier);
2578 }
2579 return 0;
2580
2581 assign_error:
2582 while (--n >= 0) {
2583 VirtQueue *vq = &vdev->vq[n];
2584 if (!virtio_queue_get_num(vdev, n)) {
2585 continue;
2586 }
2587
2588 event_notifier_set_handler(&vq->host_notifier, NULL);
2589 r = virtio_bus_set_host_notifier(qbus, n, false);
2590 assert(r >= 0);
2591 }
2592 return err;
2593 }
2594
2595 int virtio_device_start_ioeventfd(VirtIODevice *vdev)
2596 {
2597 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2598 VirtioBusState *vbus = VIRTIO_BUS(qbus);
2599
2600 return virtio_bus_start_ioeventfd(vbus);
2601 }
2602
2603 static void virtio_device_stop_ioeventfd_impl(VirtIODevice *vdev)
2604 {
2605 VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev)));
2606 int n, r;
2607
2608 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
2609 VirtQueue *vq = &vdev->vq[n];
2610
2611 if (!virtio_queue_get_num(vdev, n)) {
2612 continue;
2613 }
2614 event_notifier_set_handler(&vq->host_notifier, NULL);
2615 r = virtio_bus_set_host_notifier(qbus, n, false);
2616 assert(r >= 0);
2617 }
2618 }
2619
2620 void virtio_device_stop_ioeventfd(VirtIODevice *vdev)
2621 {
2622 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2623 VirtioBusState *vbus = VIRTIO_BUS(qbus);
2624
2625 virtio_bus_stop_ioeventfd(vbus);
2626 }
2627
2628 int virtio_device_grab_ioeventfd(VirtIODevice *vdev)
2629 {
2630 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2631 VirtioBusState *vbus = VIRTIO_BUS(qbus);
2632
2633 return virtio_bus_grab_ioeventfd(vbus);
2634 }
2635
2636 void virtio_device_release_ioeventfd(VirtIODevice *vdev)
2637 {
2638 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2639 VirtioBusState *vbus = VIRTIO_BUS(qbus);
2640
2641 virtio_bus_release_ioeventfd(vbus);
2642 }
2643
2644 static void virtio_device_class_init(ObjectClass *klass, void *data)
2645 {
2646 /* Set the default value here. */
2647 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
2648 DeviceClass *dc = DEVICE_CLASS(klass);
2649
2650 dc->realize = virtio_device_realize;
2651 dc->unrealize = virtio_device_unrealize;
2652 dc->bus_type = TYPE_VIRTIO_BUS;
2653 dc->props = virtio_properties;
2654 vdc->start_ioeventfd = virtio_device_start_ioeventfd_impl;
2655 vdc->stop_ioeventfd = virtio_device_stop_ioeventfd_impl;
2656
2657 vdc->legacy_features |= VIRTIO_LEGACY_FEATURES;
2658 }
2659
2660 bool virtio_device_ioeventfd_enabled(VirtIODevice *vdev)
2661 {
2662 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2663 VirtioBusState *vbus = VIRTIO_BUS(qbus);
2664
2665 return virtio_bus_ioeventfd_enabled(vbus);
2666 }
2667
2668 static const TypeInfo virtio_device_info = {
2669 .name = TYPE_VIRTIO_DEVICE,
2670 .parent = TYPE_DEVICE,
2671 .instance_size = sizeof(VirtIODevice),
2672 .class_init = virtio_device_class_init,
2673 .instance_finalize = virtio_device_instance_finalize,
2674 .abstract = true,
2675 .class_size = sizeof(VirtioDeviceClass),
2676 };
2677
2678 static void virtio_register_types(void)
2679 {
2680 type_register_static(&virtio_device_info);
2681 }
2682
2683 type_init(virtio_register_types)
Random patches