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Merge remote-tracking branch 'remotes/cschoenebeck/tags/pull-9p-20201102' into staging
[mirror_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 "cpu.h"
17 #include "trace.h"
18 #include "exec/address-spaces.h"
19 #include "qemu/error-report.h"
20 #include "qemu/log.h"
21 #include "qemu/main-loop.h"
22 #include "qemu/module.h"
23 #include "hw/virtio/virtio.h"
24 #include "migration/qemu-file-types.h"
25 #include "qemu/atomic.h"
26 #include "hw/virtio/virtio-bus.h"
27 #include "hw/qdev-properties.h"
28 #include "hw/virtio/virtio-access.h"
29 #include "sysemu/dma.h"
30 #include "sysemu/runstate.h"
31 #include "standard-headers/linux/virtio_ids.h"
32
33 /*
34 * The alignment to use between consumer and producer parts of vring.
35 * x86 pagesize again. This is the default, used by transports like PCI
36 * which don't provide a means for the guest to tell the host the alignment.
37 */
38 #define VIRTIO_PCI_VRING_ALIGN 4096
39
40 typedef struct VRingDesc
41 {
42 uint64_t addr;
43 uint32_t len;
44 uint16_t flags;
45 uint16_t next;
46 } VRingDesc;
47
48 typedef struct VRingPackedDesc {
49 uint64_t addr;
50 uint32_t len;
51 uint16_t id;
52 uint16_t flags;
53 } VRingPackedDesc;
54
55 typedef struct VRingAvail
56 {
57 uint16_t flags;
58 uint16_t idx;
59 uint16_t ring[];
60 } VRingAvail;
61
62 typedef struct VRingUsedElem
63 {
64 uint32_t id;
65 uint32_t len;
66 } VRingUsedElem;
67
68 typedef struct VRingUsed
69 {
70 uint16_t flags;
71 uint16_t idx;
72 VRingUsedElem ring[];
73 } VRingUsed;
74
75 typedef struct VRingMemoryRegionCaches {
76 struct rcu_head rcu;
77 MemoryRegionCache desc;
78 MemoryRegionCache avail;
79 MemoryRegionCache used;
80 } VRingMemoryRegionCaches;
81
82 typedef struct VRing
83 {
84 unsigned int num;
85 unsigned int num_default;
86 unsigned int align;
87 hwaddr desc;
88 hwaddr avail;
89 hwaddr used;
90 VRingMemoryRegionCaches *caches;
91 } VRing;
92
93 typedef struct VRingPackedDescEvent {
94 uint16_t off_wrap;
95 uint16_t flags;
96 } VRingPackedDescEvent ;
97
98 struct VirtQueue
99 {
100 VRing vring;
101 VirtQueueElement *used_elems;
102
103 /* Next head to pop */
104 uint16_t last_avail_idx;
105 bool last_avail_wrap_counter;
106
107 /* Last avail_idx read from VQ. */
108 uint16_t shadow_avail_idx;
109 bool shadow_avail_wrap_counter;
110
111 uint16_t used_idx;
112 bool used_wrap_counter;
113
114 /* Last used index value we have signalled on */
115 uint16_t signalled_used;
116
117 /* Last used index value we have signalled on */
118 bool signalled_used_valid;
119
120 /* Notification enabled? */
121 bool notification;
122
123 uint16_t queue_index;
124
125 unsigned int inuse;
126
127 uint16_t vector;
128 VirtIOHandleOutput handle_output;
129 VirtIOHandleAIOOutput handle_aio_output;
130 VirtIODevice *vdev;
131 EventNotifier guest_notifier;
132 EventNotifier host_notifier;
133 bool host_notifier_enabled;
134 QLIST_ENTRY(VirtQueue) node;
135 };
136
137 static void virtio_free_region_cache(VRingMemoryRegionCaches *caches)
138 {
139 if (!caches) {
140 return;
141 }
142
143 address_space_cache_destroy(&caches->desc);
144 address_space_cache_destroy(&caches->avail);
145 address_space_cache_destroy(&caches->used);
146 g_free(caches);
147 }
148
149 static void virtio_virtqueue_reset_region_cache(struct VirtQueue *vq)
150 {
151 VRingMemoryRegionCaches *caches;
152
153 caches = qatomic_read(&vq->vring.caches);
154 qatomic_rcu_set(&vq->vring.caches, NULL);
155 if (caches) {
156 call_rcu(caches, virtio_free_region_cache, rcu);
157 }
158 }
159
160 static void virtio_init_region_cache(VirtIODevice *vdev, int n)
161 {
162 VirtQueue *vq = &vdev->vq[n];
163 VRingMemoryRegionCaches *old = vq->vring.caches;
164 VRingMemoryRegionCaches *new = NULL;
165 hwaddr addr, size;
166 int64_t len;
167 bool packed;
168
169
170 addr = vq->vring.desc;
171 if (!addr) {
172 goto out_no_cache;
173 }
174 new = g_new0(VRingMemoryRegionCaches, 1);
175 size = virtio_queue_get_desc_size(vdev, n);
176 packed = virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED) ?
177 true : false;
178 len = address_space_cache_init(&new->desc, vdev->dma_as,
179 addr, size, packed);
180 if (len < size) {
181 virtio_error(vdev, "Cannot map desc");
182 goto err_desc;
183 }
184
185 size = virtio_queue_get_used_size(vdev, n);
186 len = address_space_cache_init(&new->used, vdev->dma_as,
187 vq->vring.used, size, true);
188 if (len < size) {
189 virtio_error(vdev, "Cannot map used");
190 goto err_used;
191 }
192
193 size = virtio_queue_get_avail_size(vdev, n);
194 len = address_space_cache_init(&new->avail, vdev->dma_as,
195 vq->vring.avail, size, false);
196 if (len < size) {
197 virtio_error(vdev, "Cannot map avail");
198 goto err_avail;
199 }
200
201 qatomic_rcu_set(&vq->vring.caches, new);
202 if (old) {
203 call_rcu(old, virtio_free_region_cache, rcu);
204 }
205 return;
206
207 err_avail:
208 address_space_cache_destroy(&new->avail);
209 err_used:
210 address_space_cache_destroy(&new->used);
211 err_desc:
212 address_space_cache_destroy(&new->desc);
213 out_no_cache:
214 g_free(new);
215 virtio_virtqueue_reset_region_cache(vq);
216 }
217
218 /* virt queue functions */
219 void virtio_queue_update_rings(VirtIODevice *vdev, int n)
220 {
221 VRing *vring = &vdev->vq[n].vring;
222
223 if (!vring->num || !vring->desc || !vring->align) {
224 /* not yet setup -> nothing to do */
225 return;
226 }
227 vring->avail = vring->desc + vring->num * sizeof(VRingDesc);
228 vring->used = vring_align(vring->avail +
229 offsetof(VRingAvail, ring[vring->num]),
230 vring->align);
231 virtio_init_region_cache(vdev, n);
232 }
233
234 /* Called within rcu_read_lock(). */
235 static void vring_split_desc_read(VirtIODevice *vdev, VRingDesc *desc,
236 MemoryRegionCache *cache, int i)
237 {
238 address_space_read_cached(cache, i * sizeof(VRingDesc),
239 desc, sizeof(VRingDesc));
240 virtio_tswap64s(vdev, &desc->addr);
241 virtio_tswap32s(vdev, &desc->len);
242 virtio_tswap16s(vdev, &desc->flags);
243 virtio_tswap16s(vdev, &desc->next);
244 }
245
246 static void vring_packed_event_read(VirtIODevice *vdev,
247 MemoryRegionCache *cache,
248 VRingPackedDescEvent *e)
249 {
250 hwaddr off_off = offsetof(VRingPackedDescEvent, off_wrap);
251 hwaddr off_flags = offsetof(VRingPackedDescEvent, flags);
252
253 address_space_read_cached(cache, off_flags, &e->flags,
254 sizeof(e->flags));
255 /* Make sure flags is seen before off_wrap */
256 smp_rmb();
257 address_space_read_cached(cache, off_off, &e->off_wrap,
258 sizeof(e->off_wrap));
259 virtio_tswap16s(vdev, &e->off_wrap);
260 virtio_tswap16s(vdev, &e->flags);
261 }
262
263 static void vring_packed_off_wrap_write(VirtIODevice *vdev,
264 MemoryRegionCache *cache,
265 uint16_t off_wrap)
266 {
267 hwaddr off = offsetof(VRingPackedDescEvent, off_wrap);
268
269 virtio_tswap16s(vdev, &off_wrap);
270 address_space_write_cached(cache, off, &off_wrap, sizeof(off_wrap));
271 address_space_cache_invalidate(cache, off, sizeof(off_wrap));
272 }
273
274 static void vring_packed_flags_write(VirtIODevice *vdev,
275 MemoryRegionCache *cache, uint16_t flags)
276 {
277 hwaddr off = offsetof(VRingPackedDescEvent, flags);
278
279 virtio_tswap16s(vdev, &flags);
280 address_space_write_cached(cache, off, &flags, sizeof(flags));
281 address_space_cache_invalidate(cache, off, sizeof(flags));
282 }
283
284 /* Called within rcu_read_lock(). */
285 static VRingMemoryRegionCaches *vring_get_region_caches(struct VirtQueue *vq)
286 {
287 return qatomic_rcu_read(&vq->vring.caches);
288 }
289
290 /* Called within rcu_read_lock(). */
291 static inline uint16_t vring_avail_flags(VirtQueue *vq)
292 {
293 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
294 hwaddr pa = offsetof(VRingAvail, flags);
295
296 if (!caches) {
297 return 0;
298 }
299
300 return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
301 }
302
303 /* Called within rcu_read_lock(). */
304 static inline uint16_t vring_avail_idx(VirtQueue *vq)
305 {
306 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
307 hwaddr pa = offsetof(VRingAvail, idx);
308
309 if (!caches) {
310 return 0;
311 }
312
313 vq->shadow_avail_idx = virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
314 return vq->shadow_avail_idx;
315 }
316
317 /* Called within rcu_read_lock(). */
318 static inline uint16_t vring_avail_ring(VirtQueue *vq, int i)
319 {
320 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
321 hwaddr pa = offsetof(VRingAvail, ring[i]);
322
323 if (!caches) {
324 return 0;
325 }
326
327 return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
328 }
329
330 /* Called within rcu_read_lock(). */
331 static inline uint16_t vring_get_used_event(VirtQueue *vq)
332 {
333 return vring_avail_ring(vq, vq->vring.num);
334 }
335
336 /* Called within rcu_read_lock(). */
337 static inline void vring_used_write(VirtQueue *vq, VRingUsedElem *uelem,
338 int i)
339 {
340 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
341 hwaddr pa = offsetof(VRingUsed, ring[i]);
342
343 if (!caches) {
344 return;
345 }
346
347 virtio_tswap32s(vq->vdev, &uelem->id);
348 virtio_tswap32s(vq->vdev, &uelem->len);
349 address_space_write_cached(&caches->used, pa, uelem, sizeof(VRingUsedElem));
350 address_space_cache_invalidate(&caches->used, pa, sizeof(VRingUsedElem));
351 }
352
353 /* Called within rcu_read_lock(). */
354 static uint16_t vring_used_idx(VirtQueue *vq)
355 {
356 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
357 hwaddr pa = offsetof(VRingUsed, idx);
358
359 if (!caches) {
360 return 0;
361 }
362
363 return virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
364 }
365
366 /* Called within rcu_read_lock(). */
367 static inline void vring_used_idx_set(VirtQueue *vq, uint16_t val)
368 {
369 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
370 hwaddr pa = offsetof(VRingUsed, idx);
371
372 if (caches) {
373 virtio_stw_phys_cached(vq->vdev, &caches->used, pa, val);
374 address_space_cache_invalidate(&caches->used, pa, sizeof(val));
375 }
376
377 vq->used_idx = val;
378 }
379
380 /* Called within rcu_read_lock(). */
381 static inline void vring_used_flags_set_bit(VirtQueue *vq, int mask)
382 {
383 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
384 VirtIODevice *vdev = vq->vdev;
385 hwaddr pa = offsetof(VRingUsed, flags);
386 uint16_t flags;
387
388 if (!caches) {
389 return;
390 }
391
392 flags = virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
393 virtio_stw_phys_cached(vdev, &caches->used, pa, flags | mask);
394 address_space_cache_invalidate(&caches->used, pa, sizeof(flags));
395 }
396
397 /* Called within rcu_read_lock(). */
398 static inline void vring_used_flags_unset_bit(VirtQueue *vq, int mask)
399 {
400 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
401 VirtIODevice *vdev = vq->vdev;
402 hwaddr pa = offsetof(VRingUsed, flags);
403 uint16_t flags;
404
405 if (!caches) {
406 return;
407 }
408
409 flags = virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
410 virtio_stw_phys_cached(vdev, &caches->used, pa, flags & ~mask);
411 address_space_cache_invalidate(&caches->used, pa, sizeof(flags));
412 }
413
414 /* Called within rcu_read_lock(). */
415 static inline void vring_set_avail_event(VirtQueue *vq, uint16_t val)
416 {
417 VRingMemoryRegionCaches *caches;
418 hwaddr pa;
419 if (!vq->notification) {
420 return;
421 }
422
423 caches = vring_get_region_caches(vq);
424 if (!caches) {
425 return;
426 }
427
428 pa = offsetof(VRingUsed, ring[vq->vring.num]);
429 virtio_stw_phys_cached(vq->vdev, &caches->used, pa, val);
430 address_space_cache_invalidate(&caches->used, pa, sizeof(val));
431 }
432
433 static void virtio_queue_split_set_notification(VirtQueue *vq, int enable)
434 {
435 RCU_READ_LOCK_GUARD();
436
437 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
438 vring_set_avail_event(vq, vring_avail_idx(vq));
439 } else if (enable) {
440 vring_used_flags_unset_bit(vq, VRING_USED_F_NO_NOTIFY);
441 } else {
442 vring_used_flags_set_bit(vq, VRING_USED_F_NO_NOTIFY);
443 }
444 if (enable) {
445 /* Expose avail event/used flags before caller checks the avail idx. */
446 smp_mb();
447 }
448 }
449
450 static void virtio_queue_packed_set_notification(VirtQueue *vq, int enable)
451 {
452 uint16_t off_wrap;
453 VRingPackedDescEvent e;
454 VRingMemoryRegionCaches *caches;
455
456 RCU_READ_LOCK_GUARD();
457 caches = vring_get_region_caches(vq);
458 if (!caches) {
459 return;
460 }
461
462 vring_packed_event_read(vq->vdev, &caches->used, &e);
463
464 if (!enable) {
465 e.flags = VRING_PACKED_EVENT_FLAG_DISABLE;
466 } else if (virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
467 off_wrap = vq->shadow_avail_idx | vq->shadow_avail_wrap_counter << 15;
468 vring_packed_off_wrap_write(vq->vdev, &caches->used, off_wrap);
469 /* Make sure off_wrap is wrote before flags */
470 smp_wmb();
471 e.flags = VRING_PACKED_EVENT_FLAG_DESC;
472 } else {
473 e.flags = VRING_PACKED_EVENT_FLAG_ENABLE;
474 }
475
476 vring_packed_flags_write(vq->vdev, &caches->used, e.flags);
477 if (enable) {
478 /* Expose avail event/used flags before caller checks the avail idx. */
479 smp_mb();
480 }
481 }
482
483 bool virtio_queue_get_notification(VirtQueue *vq)
484 {
485 return vq->notification;
486 }
487
488 void virtio_queue_set_notification(VirtQueue *vq, int enable)
489 {
490 vq->notification = enable;
491
492 if (!vq->vring.desc) {
493 return;
494 }
495
496 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
497 virtio_queue_packed_set_notification(vq, enable);
498 } else {
499 virtio_queue_split_set_notification(vq, enable);
500 }
501 }
502
503 int virtio_queue_ready(VirtQueue *vq)
504 {
505 return vq->vring.avail != 0;
506 }
507
508 static void vring_packed_desc_read_flags(VirtIODevice *vdev,
509 uint16_t *flags,
510 MemoryRegionCache *cache,
511 int i)
512 {
513 address_space_read_cached(cache,
514 i * sizeof(VRingPackedDesc) +
515 offsetof(VRingPackedDesc, flags),
516 flags, sizeof(*flags));
517 virtio_tswap16s(vdev, flags);
518 }
519
520 static void vring_packed_desc_read(VirtIODevice *vdev,
521 VRingPackedDesc *desc,
522 MemoryRegionCache *cache,
523 int i, bool strict_order)
524 {
525 hwaddr off = i * sizeof(VRingPackedDesc);
526
527 vring_packed_desc_read_flags(vdev, &desc->flags, cache, i);
528
529 if (strict_order) {
530 /* Make sure flags is read before the rest fields. */
531 smp_rmb();
532 }
533
534 address_space_read_cached(cache, off + offsetof(VRingPackedDesc, addr),
535 &desc->addr, sizeof(desc->addr));
536 address_space_read_cached(cache, off + offsetof(VRingPackedDesc, id),
537 &desc->id, sizeof(desc->id));
538 address_space_read_cached(cache, off + offsetof(VRingPackedDesc, len),
539 &desc->len, sizeof(desc->len));
540 virtio_tswap64s(vdev, &desc->addr);
541 virtio_tswap16s(vdev, &desc->id);
542 virtio_tswap32s(vdev, &desc->len);
543 }
544
545 static void vring_packed_desc_write_data(VirtIODevice *vdev,
546 VRingPackedDesc *desc,
547 MemoryRegionCache *cache,
548 int i)
549 {
550 hwaddr off_id = i * sizeof(VRingPackedDesc) +
551 offsetof(VRingPackedDesc, id);
552 hwaddr off_len = i * sizeof(VRingPackedDesc) +
553 offsetof(VRingPackedDesc, len);
554
555 virtio_tswap32s(vdev, &desc->len);
556 virtio_tswap16s(vdev, &desc->id);
557 address_space_write_cached(cache, off_id, &desc->id, sizeof(desc->id));
558 address_space_cache_invalidate(cache, off_id, sizeof(desc->id));
559 address_space_write_cached(cache, off_len, &desc->len, sizeof(desc->len));
560 address_space_cache_invalidate(cache, off_len, sizeof(desc->len));
561 }
562
563 static void vring_packed_desc_write_flags(VirtIODevice *vdev,
564 VRingPackedDesc *desc,
565 MemoryRegionCache *cache,
566 int i)
567 {
568 hwaddr off = i * sizeof(VRingPackedDesc) + offsetof(VRingPackedDesc, flags);
569
570 virtio_tswap16s(vdev, &desc->flags);
571 address_space_write_cached(cache, off, &desc->flags, sizeof(desc->flags));
572 address_space_cache_invalidate(cache, off, sizeof(desc->flags));
573 }
574
575 static void vring_packed_desc_write(VirtIODevice *vdev,
576 VRingPackedDesc *desc,
577 MemoryRegionCache *cache,
578 int i, bool strict_order)
579 {
580 vring_packed_desc_write_data(vdev, desc, cache, i);
581 if (strict_order) {
582 /* Make sure data is wrote before flags. */
583 smp_wmb();
584 }
585 vring_packed_desc_write_flags(vdev, desc, cache, i);
586 }
587
588 static inline bool is_desc_avail(uint16_t flags, bool wrap_counter)
589 {
590 bool avail, used;
591
592 avail = !!(flags & (1 << VRING_PACKED_DESC_F_AVAIL));
593 used = !!(flags & (1 << VRING_PACKED_DESC_F_USED));
594 return (avail != used) && (avail == wrap_counter);
595 }
596
597 /* Fetch avail_idx from VQ memory only when we really need to know if
598 * guest has added some buffers.
599 * Called within rcu_read_lock(). */
600 static int virtio_queue_empty_rcu(VirtQueue *vq)
601 {
602 if (virtio_device_disabled(vq->vdev)) {
603 return 1;
604 }
605
606 if (unlikely(!vq->vring.avail)) {
607 return 1;
608 }
609
610 if (vq->shadow_avail_idx != vq->last_avail_idx) {
611 return 0;
612 }
613
614 return vring_avail_idx(vq) == vq->last_avail_idx;
615 }
616
617 static int virtio_queue_split_empty(VirtQueue *vq)
618 {
619 bool empty;
620
621 if (virtio_device_disabled(vq->vdev)) {
622 return 1;
623 }
624
625 if (unlikely(!vq->vring.avail)) {
626 return 1;
627 }
628
629 if (vq->shadow_avail_idx != vq->last_avail_idx) {
630 return 0;
631 }
632
633 RCU_READ_LOCK_GUARD();
634 empty = vring_avail_idx(vq) == vq->last_avail_idx;
635 return empty;
636 }
637
638 static int virtio_queue_packed_empty_rcu(VirtQueue *vq)
639 {
640 struct VRingPackedDesc desc;
641 VRingMemoryRegionCaches *cache;
642
643 if (unlikely(!vq->vring.desc)) {
644 return 1;
645 }
646
647 cache = vring_get_region_caches(vq);
648 if (!cache) {
649 return 1;
650 }
651
652 vring_packed_desc_read_flags(vq->vdev, &desc.flags, &cache->desc,
653 vq->last_avail_idx);
654
655 return !is_desc_avail(desc.flags, vq->last_avail_wrap_counter);
656 }
657
658 static int virtio_queue_packed_empty(VirtQueue *vq)
659 {
660 RCU_READ_LOCK_GUARD();
661 return virtio_queue_packed_empty_rcu(vq);
662 }
663
664 int virtio_queue_empty(VirtQueue *vq)
665 {
666 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
667 return virtio_queue_packed_empty(vq);
668 } else {
669 return virtio_queue_split_empty(vq);
670 }
671 }
672
673 static void virtqueue_unmap_sg(VirtQueue *vq, const VirtQueueElement *elem,
674 unsigned int len)
675 {
676 AddressSpace *dma_as = vq->vdev->dma_as;
677 unsigned int offset;
678 int i;
679
680 offset = 0;
681 for (i = 0; i < elem->in_num; i++) {
682 size_t size = MIN(len - offset, elem->in_sg[i].iov_len);
683
684 dma_memory_unmap(dma_as, elem->in_sg[i].iov_base,
685 elem->in_sg[i].iov_len,
686 DMA_DIRECTION_FROM_DEVICE, size);
687
688 offset += size;
689 }
690
691 for (i = 0; i < elem->out_num; i++)
692 dma_memory_unmap(dma_as, elem->out_sg[i].iov_base,
693 elem->out_sg[i].iov_len,
694 DMA_DIRECTION_TO_DEVICE,
695 elem->out_sg[i].iov_len);
696 }
697
698 /* virtqueue_detach_element:
699 * @vq: The #VirtQueue
700 * @elem: The #VirtQueueElement
701 * @len: number of bytes written
702 *
703 * Detach the element from the virtqueue. This function is suitable for device
704 * reset or other situations where a #VirtQueueElement is simply freed and will
705 * not be pushed or discarded.
706 */
707 void virtqueue_detach_element(VirtQueue *vq, const VirtQueueElement *elem,
708 unsigned int len)
709 {
710 vq->inuse -= elem->ndescs;
711 virtqueue_unmap_sg(vq, elem, len);
712 }
713
714 static void virtqueue_split_rewind(VirtQueue *vq, unsigned int num)
715 {
716 vq->last_avail_idx -= num;
717 }
718
719 static void virtqueue_packed_rewind(VirtQueue *vq, unsigned int num)
720 {
721 if (vq->last_avail_idx < num) {
722 vq->last_avail_idx = vq->vring.num + vq->last_avail_idx - num;
723 vq->last_avail_wrap_counter ^= 1;
724 } else {
725 vq->last_avail_idx -= num;
726 }
727 }
728
729 /* virtqueue_unpop:
730 * @vq: The #VirtQueue
731 * @elem: The #VirtQueueElement
732 * @len: number of bytes written
733 *
734 * Pretend the most recent element wasn't popped from the virtqueue. The next
735 * call to virtqueue_pop() will refetch the element.
736 */
737 void virtqueue_unpop(VirtQueue *vq, const VirtQueueElement *elem,
738 unsigned int len)
739 {
740
741 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
742 virtqueue_packed_rewind(vq, 1);
743 } else {
744 virtqueue_split_rewind(vq, 1);
745 }
746
747 virtqueue_detach_element(vq, elem, len);
748 }
749
750 /* virtqueue_rewind:
751 * @vq: The #VirtQueue
752 * @num: Number of elements to push back
753 *
754 * Pretend that elements weren't popped from the virtqueue. The next
755 * virtqueue_pop() will refetch the oldest element.
756 *
757 * Use virtqueue_unpop() instead if you have a VirtQueueElement.
758 *
759 * Returns: true on success, false if @num is greater than the number of in use
760 * elements.
761 */
762 bool virtqueue_rewind(VirtQueue *vq, unsigned int num)
763 {
764 if (num > vq->inuse) {
765 return false;
766 }
767
768 vq->inuse -= num;
769 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
770 virtqueue_packed_rewind(vq, num);
771 } else {
772 virtqueue_split_rewind(vq, num);
773 }
774 return true;
775 }
776
777 static void virtqueue_split_fill(VirtQueue *vq, const VirtQueueElement *elem,
778 unsigned int len, unsigned int idx)
779 {
780 VRingUsedElem uelem;
781
782 if (unlikely(!vq->vring.used)) {
783 return;
784 }
785
786 idx = (idx + vq->used_idx) % vq->vring.num;
787
788 uelem.id = elem->index;
789 uelem.len = len;
790 vring_used_write(vq, &uelem, idx);
791 }
792
793 static void virtqueue_packed_fill(VirtQueue *vq, const VirtQueueElement *elem,
794 unsigned int len, unsigned int idx)
795 {
796 vq->used_elems[idx].index = elem->index;
797 vq->used_elems[idx].len = len;
798 vq->used_elems[idx].ndescs = elem->ndescs;
799 }
800
801 static void virtqueue_packed_fill_desc(VirtQueue *vq,
802 const VirtQueueElement *elem,
803 unsigned int idx,
804 bool strict_order)
805 {
806 uint16_t head;
807 VRingMemoryRegionCaches *caches;
808 VRingPackedDesc desc = {
809 .id = elem->index,
810 .len = elem->len,
811 };
812 bool wrap_counter = vq->used_wrap_counter;
813
814 if (unlikely(!vq->vring.desc)) {
815 return;
816 }
817
818 head = vq->used_idx + idx;
819 if (head >= vq->vring.num) {
820 head -= vq->vring.num;
821 wrap_counter ^= 1;
822 }
823 if (wrap_counter) {
824 desc.flags |= (1 << VRING_PACKED_DESC_F_AVAIL);
825 desc.flags |= (1 << VRING_PACKED_DESC_F_USED);
826 } else {
827 desc.flags &= ~(1 << VRING_PACKED_DESC_F_AVAIL);
828 desc.flags &= ~(1 << VRING_PACKED_DESC_F_USED);
829 }
830
831 caches = vring_get_region_caches(vq);
832 if (!caches) {
833 return;
834 }
835
836 vring_packed_desc_write(vq->vdev, &desc, &caches->desc, head, strict_order);
837 }
838
839 /* Called within rcu_read_lock(). */
840 void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
841 unsigned int len, unsigned int idx)
842 {
843 trace_virtqueue_fill(vq, elem, len, idx);
844
845 virtqueue_unmap_sg(vq, elem, len);
846
847 if (virtio_device_disabled(vq->vdev)) {
848 return;
849 }
850
851 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
852 virtqueue_packed_fill(vq, elem, len, idx);
853 } else {
854 virtqueue_split_fill(vq, elem, len, idx);
855 }
856 }
857
858 /* Called within rcu_read_lock(). */
859 static void virtqueue_split_flush(VirtQueue *vq, unsigned int count)
860 {
861 uint16_t old, new;
862
863 if (unlikely(!vq->vring.used)) {
864 return;
865 }
866
867 /* Make sure buffer is written before we update index. */
868 smp_wmb();
869 trace_virtqueue_flush(vq, count);
870 old = vq->used_idx;
871 new = old + count;
872 vring_used_idx_set(vq, new);
873 vq->inuse -= count;
874 if (unlikely((int16_t)(new - vq->signalled_used) < (uint16_t)(new - old)))
875 vq->signalled_used_valid = false;
876 }
877
878 static void virtqueue_packed_flush(VirtQueue *vq, unsigned int count)
879 {
880 unsigned int i, ndescs = 0;
881
882 if (unlikely(!vq->vring.desc)) {
883 return;
884 }
885
886 for (i = 1; i < count; i++) {
887 virtqueue_packed_fill_desc(vq, &vq->used_elems[i], i, false);
888 ndescs += vq->used_elems[i].ndescs;
889 }
890 virtqueue_packed_fill_desc(vq, &vq->used_elems[0], 0, true);
891 ndescs += vq->used_elems[0].ndescs;
892
893 vq->inuse -= ndescs;
894 vq->used_idx += ndescs;
895 if (vq->used_idx >= vq->vring.num) {
896 vq->used_idx -= vq->vring.num;
897 vq->used_wrap_counter ^= 1;
898 }
899 }
900
901 void virtqueue_flush(VirtQueue *vq, unsigned int count)
902 {
903 if (virtio_device_disabled(vq->vdev)) {
904 vq->inuse -= count;
905 return;
906 }
907
908 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
909 virtqueue_packed_flush(vq, count);
910 } else {
911 virtqueue_split_flush(vq, count);
912 }
913 }
914
915 void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
916 unsigned int len)
917 {
918 RCU_READ_LOCK_GUARD();
919 virtqueue_fill(vq, elem, len, 0);
920 virtqueue_flush(vq, 1);
921 }
922
923 /* Called within rcu_read_lock(). */
924 static int virtqueue_num_heads(VirtQueue *vq, unsigned int idx)
925 {
926 uint16_t num_heads = vring_avail_idx(vq) - idx;
927
928 /* Check it isn't doing very strange things with descriptor numbers. */
929 if (num_heads > vq->vring.num) {
930 virtio_error(vq->vdev, "Guest moved used index from %u to %u",
931 idx, vq->shadow_avail_idx);
932 return -EINVAL;
933 }
934 /* On success, callers read a descriptor at vq->last_avail_idx.
935 * Make sure descriptor read does not bypass avail index read. */
936 if (num_heads) {
937 smp_rmb();
938 }
939
940 return num_heads;
941 }
942
943 /* Called within rcu_read_lock(). */
944 static bool virtqueue_get_head(VirtQueue *vq, unsigned int idx,
945 unsigned int *head)
946 {
947 /* Grab the next descriptor number they're advertising, and increment
948 * the index we've seen. */
949 *head = vring_avail_ring(vq, idx % vq->vring.num);
950
951 /* If their number is silly, that's a fatal mistake. */
952 if (*head >= vq->vring.num) {
953 virtio_error(vq->vdev, "Guest says index %u is available", *head);
954 return false;
955 }
956
957 return true;
958 }
959
960 enum {
961 VIRTQUEUE_READ_DESC_ERROR = -1,
962 VIRTQUEUE_READ_DESC_DONE = 0, /* end of chain */
963 VIRTQUEUE_READ_DESC_MORE = 1, /* more buffers in chain */
964 };
965
966 static int virtqueue_split_read_next_desc(VirtIODevice *vdev, VRingDesc *desc,
967 MemoryRegionCache *desc_cache,
968 unsigned int max, unsigned int *next)
969 {
970 /* If this descriptor says it doesn't chain, we're done. */
971 if (!(desc->flags & VRING_DESC_F_NEXT)) {
972 return VIRTQUEUE_READ_DESC_DONE;
973 }
974
975 /* Check they're not leading us off end of descriptors. */
976 *next = desc->next;
977 /* Make sure compiler knows to grab that: we don't want it changing! */
978 smp_wmb();
979
980 if (*next >= max) {
981 virtio_error(vdev, "Desc next is %u", *next);
982 return VIRTQUEUE_READ_DESC_ERROR;
983 }
984
985 vring_split_desc_read(vdev, desc, desc_cache, *next);
986 return VIRTQUEUE_READ_DESC_MORE;
987 }
988
989 static void virtqueue_split_get_avail_bytes(VirtQueue *vq,
990 unsigned int *in_bytes, unsigned int *out_bytes,
991 unsigned max_in_bytes, unsigned max_out_bytes)
992 {
993 VirtIODevice *vdev = vq->vdev;
994 unsigned int max, idx;
995 unsigned int total_bufs, in_total, out_total;
996 VRingMemoryRegionCaches *caches;
997 MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
998 int64_t len = 0;
999 int rc;
1000
1001 RCU_READ_LOCK_GUARD();
1002
1003 idx = vq->last_avail_idx;
1004 total_bufs = in_total = out_total = 0;
1005
1006 max = vq->vring.num;
1007 caches = vring_get_region_caches(vq);
1008 if (!caches) {
1009 goto err;
1010 }
1011
1012 while ((rc = virtqueue_num_heads(vq, idx)) > 0) {
1013 MemoryRegionCache *desc_cache = &caches->desc;
1014 unsigned int num_bufs;
1015 VRingDesc desc;
1016 unsigned int i;
1017
1018 num_bufs = total_bufs;
1019
1020 if (!virtqueue_get_head(vq, idx++, &i)) {
1021 goto err;
1022 }
1023
1024 vring_split_desc_read(vdev, &desc, desc_cache, i);
1025
1026 if (desc.flags & VRING_DESC_F_INDIRECT) {
1027 if (!desc.len || (desc.len % sizeof(VRingDesc))) {
1028 virtio_error(vdev, "Invalid size for indirect buffer table");
1029 goto err;
1030 }
1031
1032 /* If we've got too many, that implies a descriptor loop. */
1033 if (num_bufs >= max) {
1034 virtio_error(vdev, "Looped descriptor");
1035 goto err;
1036 }
1037
1038 /* loop over the indirect descriptor table */
1039 len = address_space_cache_init(&indirect_desc_cache,
1040 vdev->dma_as,
1041 desc.addr, desc.len, false);
1042 desc_cache = &indirect_desc_cache;
1043 if (len < desc.len) {
1044 virtio_error(vdev, "Cannot map indirect buffer");
1045 goto err;
1046 }
1047
1048 max = desc.len / sizeof(VRingDesc);
1049 num_bufs = i = 0;
1050 vring_split_desc_read(vdev, &desc, desc_cache, i);
1051 }
1052
1053 do {
1054 /* If we've got too many, that implies a descriptor loop. */
1055 if (++num_bufs > max) {
1056 virtio_error(vdev, "Looped descriptor");
1057 goto err;
1058 }
1059
1060 if (desc.flags & VRING_DESC_F_WRITE) {
1061 in_total += desc.len;
1062 } else {
1063 out_total += desc.len;
1064 }
1065 if (in_total >= max_in_bytes && out_total >= max_out_bytes) {
1066 goto done;
1067 }
1068
1069 rc = virtqueue_split_read_next_desc(vdev, &desc, desc_cache, max, &i);
1070 } while (rc == VIRTQUEUE_READ_DESC_MORE);
1071
1072 if (rc == VIRTQUEUE_READ_DESC_ERROR) {
1073 goto err;
1074 }
1075
1076 if (desc_cache == &indirect_desc_cache) {
1077 address_space_cache_destroy(&indirect_desc_cache);
1078 total_bufs++;
1079 } else {
1080 total_bufs = num_bufs;
1081 }
1082 }
1083
1084 if (rc < 0) {
1085 goto err;
1086 }
1087
1088 done:
1089 address_space_cache_destroy(&indirect_desc_cache);
1090 if (in_bytes) {
1091 *in_bytes = in_total;
1092 }
1093 if (out_bytes) {
1094 *out_bytes = out_total;
1095 }
1096 return;
1097
1098 err:
1099 in_total = out_total = 0;
1100 goto done;
1101 }
1102
1103 static int virtqueue_packed_read_next_desc(VirtQueue *vq,
1104 VRingPackedDesc *desc,
1105 MemoryRegionCache
1106 *desc_cache,
1107 unsigned int max,
1108 unsigned int *next,
1109 bool indirect)
1110 {
1111 /* If this descriptor says it doesn't chain, we're done. */
1112 if (!indirect && !(desc->flags & VRING_DESC_F_NEXT)) {
1113 return VIRTQUEUE_READ_DESC_DONE;
1114 }
1115
1116 ++*next;
1117 if (*next == max) {
1118 if (indirect) {
1119 return VIRTQUEUE_READ_DESC_DONE;
1120 } else {
1121 (*next) -= vq->vring.num;
1122 }
1123 }
1124
1125 vring_packed_desc_read(vq->vdev, desc, desc_cache, *next, false);
1126 return VIRTQUEUE_READ_DESC_MORE;
1127 }
1128
1129 static void virtqueue_packed_get_avail_bytes(VirtQueue *vq,
1130 unsigned int *in_bytes,
1131 unsigned int *out_bytes,
1132 unsigned max_in_bytes,
1133 unsigned max_out_bytes)
1134 {
1135 VirtIODevice *vdev = vq->vdev;
1136 unsigned int max, idx;
1137 unsigned int total_bufs, in_total, out_total;
1138 MemoryRegionCache *desc_cache;
1139 VRingMemoryRegionCaches *caches;
1140 MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
1141 int64_t len = 0;
1142 VRingPackedDesc desc;
1143 bool wrap_counter;
1144
1145 RCU_READ_LOCK_GUARD();
1146 idx = vq->last_avail_idx;
1147 wrap_counter = vq->last_avail_wrap_counter;
1148 total_bufs = in_total = out_total = 0;
1149
1150 max = vq->vring.num;
1151 caches = vring_get_region_caches(vq);
1152 if (!caches) {
1153 goto err;
1154 }
1155
1156 for (;;) {
1157 unsigned int num_bufs = total_bufs;
1158 unsigned int i = idx;
1159 int rc;
1160
1161 desc_cache = &caches->desc;
1162 vring_packed_desc_read(vdev, &desc, desc_cache, idx, true);
1163 if (!is_desc_avail(desc.flags, wrap_counter)) {
1164 break;
1165 }
1166
1167 if (desc.flags & VRING_DESC_F_INDIRECT) {
1168 if (desc.len % sizeof(VRingPackedDesc)) {
1169 virtio_error(vdev, "Invalid size for indirect buffer table");
1170 goto err;
1171 }
1172
1173 /* If we've got too many, that implies a descriptor loop. */
1174 if (num_bufs >= max) {
1175 virtio_error(vdev, "Looped descriptor");
1176 goto err;
1177 }
1178
1179 /* loop over the indirect descriptor table */
1180 len = address_space_cache_init(&indirect_desc_cache,
1181 vdev->dma_as,
1182 desc.addr, desc.len, false);
1183 desc_cache = &indirect_desc_cache;
1184 if (len < desc.len) {
1185 virtio_error(vdev, "Cannot map indirect buffer");
1186 goto err;
1187 }
1188
1189 max = desc.len / sizeof(VRingPackedDesc);
1190 num_bufs = i = 0;
1191 vring_packed_desc_read(vdev, &desc, desc_cache, i, false);
1192 }
1193
1194 do {
1195 /* If we've got too many, that implies a descriptor loop. */
1196 if (++num_bufs > max) {
1197 virtio_error(vdev, "Looped descriptor");
1198 goto err;
1199 }
1200
1201 if (desc.flags & VRING_DESC_F_WRITE) {
1202 in_total += desc.len;
1203 } else {
1204 out_total += desc.len;
1205 }
1206 if (in_total >= max_in_bytes && out_total >= max_out_bytes) {
1207 goto done;
1208 }
1209
1210 rc = virtqueue_packed_read_next_desc(vq, &desc, desc_cache, max,
1211 &i, desc_cache ==
1212 &indirect_desc_cache);
1213 } while (rc == VIRTQUEUE_READ_DESC_MORE);
1214
1215 if (desc_cache == &indirect_desc_cache) {
1216 address_space_cache_destroy(&indirect_desc_cache);
1217 total_bufs++;
1218 idx++;
1219 } else {
1220 idx += num_bufs - total_bufs;
1221 total_bufs = num_bufs;
1222 }
1223
1224 if (idx >= vq->vring.num) {
1225 idx -= vq->vring.num;
1226 wrap_counter ^= 1;
1227 }
1228 }
1229
1230 /* Record the index and wrap counter for a kick we want */
1231 vq->shadow_avail_idx = idx;
1232 vq->shadow_avail_wrap_counter = wrap_counter;
1233 done:
1234 address_space_cache_destroy(&indirect_desc_cache);
1235 if (in_bytes) {
1236 *in_bytes = in_total;
1237 }
1238 if (out_bytes) {
1239 *out_bytes = out_total;
1240 }
1241 return;
1242
1243 err:
1244 in_total = out_total = 0;
1245 goto done;
1246 }
1247
1248 void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
1249 unsigned int *out_bytes,
1250 unsigned max_in_bytes, unsigned max_out_bytes)
1251 {
1252 uint16_t desc_size;
1253 VRingMemoryRegionCaches *caches;
1254
1255 if (unlikely(!vq->vring.desc)) {
1256 goto err;
1257 }
1258
1259 caches = vring_get_region_caches(vq);
1260 if (!caches) {
1261 goto err;
1262 }
1263
1264 desc_size = virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED) ?
1265 sizeof(VRingPackedDesc) : sizeof(VRingDesc);
1266 if (caches->desc.len < vq->vring.num * desc_size) {
1267 virtio_error(vq->vdev, "Cannot map descriptor ring");
1268 goto err;
1269 }
1270
1271 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
1272 virtqueue_packed_get_avail_bytes(vq, in_bytes, out_bytes,
1273 max_in_bytes, max_out_bytes);
1274 } else {
1275 virtqueue_split_get_avail_bytes(vq, in_bytes, out_bytes,
1276 max_in_bytes, max_out_bytes);
1277 }
1278
1279 return;
1280 err:
1281 if (in_bytes) {
1282 *in_bytes = 0;
1283 }
1284 if (out_bytes) {
1285 *out_bytes = 0;
1286 }
1287 }
1288
1289 int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes,
1290 unsigned int out_bytes)
1291 {
1292 unsigned int in_total, out_total;
1293
1294 virtqueue_get_avail_bytes(vq, &in_total, &out_total, in_bytes, out_bytes);
1295 return in_bytes <= in_total && out_bytes <= out_total;
1296 }
1297
1298 static bool virtqueue_map_desc(VirtIODevice *vdev, unsigned int *p_num_sg,
1299 hwaddr *addr, struct iovec *iov,
1300 unsigned int max_num_sg, bool is_write,
1301 hwaddr pa, size_t sz)
1302 {
1303 bool ok = false;
1304 unsigned num_sg = *p_num_sg;
1305 assert(num_sg <= max_num_sg);
1306
1307 if (!sz) {
1308 virtio_error(vdev, "virtio: zero sized buffers are not allowed");
1309 goto out;
1310 }
1311
1312 while (sz) {
1313 hwaddr len = sz;
1314
1315 if (num_sg == max_num_sg) {
1316 virtio_error(vdev, "virtio: too many write descriptors in "
1317 "indirect table");
1318 goto out;
1319 }
1320
1321 iov[num_sg].iov_base = dma_memory_map(vdev->dma_as, pa, &len,
1322 is_write ?
1323 DMA_DIRECTION_FROM_DEVICE :
1324 DMA_DIRECTION_TO_DEVICE);
1325 if (!iov[num_sg].iov_base) {
1326 virtio_error(vdev, "virtio: bogus descriptor or out of resources");
1327 goto out;
1328 }
1329
1330 iov[num_sg].iov_len = len;
1331 addr[num_sg] = pa;
1332
1333 sz -= len;
1334 pa += len;
1335 num_sg++;
1336 }
1337 ok = true;
1338
1339 out:
1340 *p_num_sg = num_sg;
1341 return ok;
1342 }
1343
1344 /* Only used by error code paths before we have a VirtQueueElement (therefore
1345 * virtqueue_unmap_sg() can't be used). Assumes buffers weren't written to
1346 * yet.
1347 */
1348 static void virtqueue_undo_map_desc(unsigned int out_num, unsigned int in_num,
1349 struct iovec *iov)
1350 {
1351 unsigned int i;
1352
1353 for (i = 0; i < out_num + in_num; i++) {
1354 int is_write = i >= out_num;
1355
1356 cpu_physical_memory_unmap(iov->iov_base, iov->iov_len, is_write, 0);
1357 iov++;
1358 }
1359 }
1360
1361 static void virtqueue_map_iovec(VirtIODevice *vdev, struct iovec *sg,
1362 hwaddr *addr, unsigned int num_sg,
1363 bool is_write)
1364 {
1365 unsigned int i;
1366 hwaddr len;
1367
1368 for (i = 0; i < num_sg; i++) {
1369 len = sg[i].iov_len;
1370 sg[i].iov_base = dma_memory_map(vdev->dma_as,
1371 addr[i], &len, is_write ?
1372 DMA_DIRECTION_FROM_DEVICE :
1373 DMA_DIRECTION_TO_DEVICE);
1374 if (!sg[i].iov_base) {
1375 error_report("virtio: error trying to map MMIO memory");
1376 exit(1);
1377 }
1378 if (len != sg[i].iov_len) {
1379 error_report("virtio: unexpected memory split");
1380 exit(1);
1381 }
1382 }
1383 }
1384
1385 void virtqueue_map(VirtIODevice *vdev, VirtQueueElement *elem)
1386 {
1387 virtqueue_map_iovec(vdev, elem->in_sg, elem->in_addr, elem->in_num, true);
1388 virtqueue_map_iovec(vdev, elem->out_sg, elem->out_addr, elem->out_num,
1389 false);
1390 }
1391
1392 static void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned in_num)
1393 {
1394 VirtQueueElement *elem;
1395 size_t in_addr_ofs = QEMU_ALIGN_UP(sz, __alignof__(elem->in_addr[0]));
1396 size_t out_addr_ofs = in_addr_ofs + in_num * sizeof(elem->in_addr[0]);
1397 size_t out_addr_end = out_addr_ofs + out_num * sizeof(elem->out_addr[0]);
1398 size_t in_sg_ofs = QEMU_ALIGN_UP(out_addr_end, __alignof__(elem->in_sg[0]));
1399 size_t out_sg_ofs = in_sg_ofs + in_num * sizeof(elem->in_sg[0]);
1400 size_t out_sg_end = out_sg_ofs + out_num * sizeof(elem->out_sg[0]);
1401
1402 assert(sz >= sizeof(VirtQueueElement));
1403 elem = g_malloc(out_sg_end);
1404 trace_virtqueue_alloc_element(elem, sz, in_num, out_num);
1405 elem->out_num = out_num;
1406 elem->in_num = in_num;
1407 elem->in_addr = (void *)elem + in_addr_ofs;
1408 elem->out_addr = (void *)elem + out_addr_ofs;
1409 elem->in_sg = (void *)elem + in_sg_ofs;
1410 elem->out_sg = (void *)elem + out_sg_ofs;
1411 return elem;
1412 }
1413
1414 static void *virtqueue_split_pop(VirtQueue *vq, size_t sz)
1415 {
1416 unsigned int i, head, max;
1417 VRingMemoryRegionCaches *caches;
1418 MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
1419 MemoryRegionCache *desc_cache;
1420 int64_t len;
1421 VirtIODevice *vdev = vq->vdev;
1422 VirtQueueElement *elem = NULL;
1423 unsigned out_num, in_num, elem_entries;
1424 hwaddr addr[VIRTQUEUE_MAX_SIZE];
1425 struct iovec iov[VIRTQUEUE_MAX_SIZE];
1426 VRingDesc desc;
1427 int rc;
1428
1429 RCU_READ_LOCK_GUARD();
1430 if (virtio_queue_empty_rcu(vq)) {
1431 goto done;
1432 }
1433 /* Needed after virtio_queue_empty(), see comment in
1434 * virtqueue_num_heads(). */
1435 smp_rmb();
1436
1437 /* When we start there are none of either input nor output. */
1438 out_num = in_num = elem_entries = 0;
1439
1440 max = vq->vring.num;
1441
1442 if (vq->inuse >= vq->vring.num) {
1443 virtio_error(vdev, "Virtqueue size exceeded");
1444 goto done;
1445 }
1446
1447 if (!virtqueue_get_head(vq, vq->last_avail_idx++, &head)) {
1448 goto done;
1449 }
1450
1451 if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
1452 vring_set_avail_event(vq, vq->last_avail_idx);
1453 }
1454
1455 i = head;
1456
1457 caches = vring_get_region_caches(vq);
1458 if (!caches) {
1459 virtio_error(vdev, "Region caches not initialized");
1460 goto done;
1461 }
1462
1463 if (caches->desc.len < max * sizeof(VRingDesc)) {
1464 virtio_error(vdev, "Cannot map descriptor ring");
1465 goto done;
1466 }
1467
1468 desc_cache = &caches->desc;
1469 vring_split_desc_read(vdev, &desc, desc_cache, i);
1470 if (desc.flags & VRING_DESC_F_INDIRECT) {
1471 if (!desc.len || (desc.len % sizeof(VRingDesc))) {
1472 virtio_error(vdev, "Invalid size for indirect buffer table");
1473 goto done;
1474 }
1475
1476 /* loop over the indirect descriptor table */
1477 len = address_space_cache_init(&indirect_desc_cache, vdev->dma_as,
1478 desc.addr, desc.len, false);
1479 desc_cache = &indirect_desc_cache;
1480 if (len < desc.len) {
1481 virtio_error(vdev, "Cannot map indirect buffer");
1482 goto done;
1483 }
1484
1485 max = desc.len / sizeof(VRingDesc);
1486 i = 0;
1487 vring_split_desc_read(vdev, &desc, desc_cache, i);
1488 }
1489
1490 /* Collect all the descriptors */
1491 do {
1492 bool map_ok;
1493
1494 if (desc.flags & VRING_DESC_F_WRITE) {
1495 map_ok = virtqueue_map_desc(vdev, &in_num, addr + out_num,
1496 iov + out_num,
1497 VIRTQUEUE_MAX_SIZE - out_num, true,
1498 desc.addr, desc.len);
1499 } else {
1500 if (in_num) {
1501 virtio_error(vdev, "Incorrect order for descriptors");
1502 goto err_undo_map;
1503 }
1504 map_ok = virtqueue_map_desc(vdev, &out_num, addr, iov,
1505 VIRTQUEUE_MAX_SIZE, false,
1506 desc.addr, desc.len);
1507 }
1508 if (!map_ok) {
1509 goto err_undo_map;
1510 }
1511
1512 /* If we've got too many, that implies a descriptor loop. */
1513 if (++elem_entries > max) {
1514 virtio_error(vdev, "Looped descriptor");
1515 goto err_undo_map;
1516 }
1517
1518 rc = virtqueue_split_read_next_desc(vdev, &desc, desc_cache, max, &i);
1519 } while (rc == VIRTQUEUE_READ_DESC_MORE);
1520
1521 if (rc == VIRTQUEUE_READ_DESC_ERROR) {
1522 goto err_undo_map;
1523 }
1524
1525 /* Now copy what we have collected and mapped */
1526 elem = virtqueue_alloc_element(sz, out_num, in_num);
1527 elem->index = head;
1528 elem->ndescs = 1;
1529 for (i = 0; i < out_num; i++) {
1530 elem->out_addr[i] = addr[i];
1531 elem->out_sg[i] = iov[i];
1532 }
1533 for (i = 0; i < in_num; i++) {
1534 elem->in_addr[i] = addr[out_num + i];
1535 elem->in_sg[i] = iov[out_num + i];
1536 }
1537
1538 vq->inuse++;
1539
1540 trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num);
1541 done:
1542 address_space_cache_destroy(&indirect_desc_cache);
1543
1544 return elem;
1545
1546 err_undo_map:
1547 virtqueue_undo_map_desc(out_num, in_num, iov);
1548 goto done;
1549 }
1550
1551 static void *virtqueue_packed_pop(VirtQueue *vq, size_t sz)
1552 {
1553 unsigned int i, max;
1554 VRingMemoryRegionCaches *caches;
1555 MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
1556 MemoryRegionCache *desc_cache;
1557 int64_t len;
1558 VirtIODevice *vdev = vq->vdev;
1559 VirtQueueElement *elem = NULL;
1560 unsigned out_num, in_num, elem_entries;
1561 hwaddr addr[VIRTQUEUE_MAX_SIZE];
1562 struct iovec iov[VIRTQUEUE_MAX_SIZE];
1563 VRingPackedDesc desc;
1564 uint16_t id;
1565 int rc;
1566
1567 RCU_READ_LOCK_GUARD();
1568 if (virtio_queue_packed_empty_rcu(vq)) {
1569 goto done;
1570 }
1571
1572 /* When we start there are none of either input nor output. */
1573 out_num = in_num = elem_entries = 0;
1574
1575 max = vq->vring.num;
1576
1577 if (vq->inuse >= vq->vring.num) {
1578 virtio_error(vdev, "Virtqueue size exceeded");
1579 goto done;
1580 }
1581
1582 i = vq->last_avail_idx;
1583
1584 caches = vring_get_region_caches(vq);
1585 if (!caches) {
1586 virtio_error(vdev, "Region caches not initialized");
1587 goto done;
1588 }
1589
1590 if (caches->desc.len < max * sizeof(VRingDesc)) {
1591 virtio_error(vdev, "Cannot map descriptor ring");
1592 goto done;
1593 }
1594
1595 desc_cache = &caches->desc;
1596 vring_packed_desc_read(vdev, &desc, desc_cache, i, true);
1597 id = desc.id;
1598 if (desc.flags & VRING_DESC_F_INDIRECT) {
1599 if (desc.len % sizeof(VRingPackedDesc)) {
1600 virtio_error(vdev, "Invalid size for indirect buffer table");
1601 goto done;
1602 }
1603
1604 /* loop over the indirect descriptor table */
1605 len = address_space_cache_init(&indirect_desc_cache, vdev->dma_as,
1606 desc.addr, desc.len, false);
1607 desc_cache = &indirect_desc_cache;
1608 if (len < desc.len) {
1609 virtio_error(vdev, "Cannot map indirect buffer");
1610 goto done;
1611 }
1612
1613 max = desc.len / sizeof(VRingPackedDesc);
1614 i = 0;
1615 vring_packed_desc_read(vdev, &desc, desc_cache, i, false);
1616 }
1617
1618 /* Collect all the descriptors */
1619 do {
1620 bool map_ok;
1621
1622 if (desc.flags & VRING_DESC_F_WRITE) {
1623 map_ok = virtqueue_map_desc(vdev, &in_num, addr + out_num,
1624 iov + out_num,
1625 VIRTQUEUE_MAX_SIZE - out_num, true,
1626 desc.addr, desc.len);
1627 } else {
1628 if (in_num) {
1629 virtio_error(vdev, "Incorrect order for descriptors");
1630 goto err_undo_map;
1631 }
1632 map_ok = virtqueue_map_desc(vdev, &out_num, addr, iov,
1633 VIRTQUEUE_MAX_SIZE, false,
1634 desc.addr, desc.len);
1635 }
1636 if (!map_ok) {
1637 goto err_undo_map;
1638 }
1639
1640 /* If we've got too many, that implies a descriptor loop. */
1641 if (++elem_entries > max) {
1642 virtio_error(vdev, "Looped descriptor");
1643 goto err_undo_map;
1644 }
1645
1646 rc = virtqueue_packed_read_next_desc(vq, &desc, desc_cache, max, &i,
1647 desc_cache ==
1648 &indirect_desc_cache);
1649 } while (rc == VIRTQUEUE_READ_DESC_MORE);
1650
1651 /* Now copy what we have collected and mapped */
1652 elem = virtqueue_alloc_element(sz, out_num, in_num);
1653 for (i = 0; i < out_num; i++) {
1654 elem->out_addr[i] = addr[i];
1655 elem->out_sg[i] = iov[i];
1656 }
1657 for (i = 0; i < in_num; i++) {
1658 elem->in_addr[i] = addr[out_num + i];
1659 elem->in_sg[i] = iov[out_num + i];
1660 }
1661
1662 elem->index = id;
1663 elem->ndescs = (desc_cache == &indirect_desc_cache) ? 1 : elem_entries;
1664 vq->last_avail_idx += elem->ndescs;
1665 vq->inuse += elem->ndescs;
1666
1667 if (vq->last_avail_idx >= vq->vring.num) {
1668 vq->last_avail_idx -= vq->vring.num;
1669 vq->last_avail_wrap_counter ^= 1;
1670 }
1671
1672 vq->shadow_avail_idx = vq->last_avail_idx;
1673 vq->shadow_avail_wrap_counter = vq->last_avail_wrap_counter;
1674
1675 trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num);
1676 done:
1677 address_space_cache_destroy(&indirect_desc_cache);
1678
1679 return elem;
1680
1681 err_undo_map:
1682 virtqueue_undo_map_desc(out_num, in_num, iov);
1683 goto done;
1684 }
1685
1686 void *virtqueue_pop(VirtQueue *vq, size_t sz)
1687 {
1688 if (virtio_device_disabled(vq->vdev)) {
1689 return NULL;
1690 }
1691
1692 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
1693 return virtqueue_packed_pop(vq, sz);
1694 } else {
1695 return virtqueue_split_pop(vq, sz);
1696 }
1697 }
1698
1699 static unsigned int virtqueue_packed_drop_all(VirtQueue *vq)
1700 {
1701 VRingMemoryRegionCaches *caches;
1702 MemoryRegionCache *desc_cache;
1703 unsigned int dropped = 0;
1704 VirtQueueElement elem = {};
1705 VirtIODevice *vdev = vq->vdev;
1706 VRingPackedDesc desc;
1707
1708 caches = vring_get_region_caches(vq);
1709 if (!caches) {
1710 return 0;
1711 }
1712
1713 desc_cache = &caches->desc;
1714
1715 virtio_queue_set_notification(vq, 0);
1716
1717 while (vq->inuse < vq->vring.num) {
1718 unsigned int idx = vq->last_avail_idx;
1719 /*
1720 * works similar to virtqueue_pop but does not map buffers
1721 * and does not allocate any memory.
1722 */
1723 vring_packed_desc_read(vdev, &desc, desc_cache,
1724 vq->last_avail_idx , true);
1725 if (!is_desc_avail(desc.flags, vq->last_avail_wrap_counter)) {
1726 break;
1727 }
1728 elem.index = desc.id;
1729 elem.ndescs = 1;
1730 while (virtqueue_packed_read_next_desc(vq, &desc, desc_cache,
1731 vq->vring.num, &idx, false)) {
1732 ++elem.ndescs;
1733 }
1734 /*
1735 * immediately push the element, nothing to unmap
1736 * as both in_num and out_num are set to 0.
1737 */
1738 virtqueue_push(vq, &elem, 0);
1739 dropped++;
1740 vq->last_avail_idx += elem.ndescs;
1741 if (vq->last_avail_idx >= vq->vring.num) {
1742 vq->last_avail_idx -= vq->vring.num;
1743 vq->last_avail_wrap_counter ^= 1;
1744 }
1745 }
1746
1747 return dropped;
1748 }
1749
1750 static unsigned int virtqueue_split_drop_all(VirtQueue *vq)
1751 {
1752 unsigned int dropped = 0;
1753 VirtQueueElement elem = {};
1754 VirtIODevice *vdev = vq->vdev;
1755 bool fEventIdx = virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
1756
1757 while (!virtio_queue_empty(vq) && vq->inuse < vq->vring.num) {
1758 /* works similar to virtqueue_pop but does not map buffers
1759 * and does not allocate any memory */
1760 smp_rmb();
1761 if (!virtqueue_get_head(vq, vq->last_avail_idx, &elem.index)) {
1762 break;
1763 }
1764 vq->inuse++;
1765 vq->last_avail_idx++;
1766 if (fEventIdx) {
1767 vring_set_avail_event(vq, vq->last_avail_idx);
1768 }
1769 /* immediately push the element, nothing to unmap
1770 * as both in_num and out_num are set to 0 */
1771 virtqueue_push(vq, &elem, 0);
1772 dropped++;
1773 }
1774
1775 return dropped;
1776 }
1777
1778 /* virtqueue_drop_all:
1779 * @vq: The #VirtQueue
1780 * Drops all queued buffers and indicates them to the guest
1781 * as if they are done. Useful when buffers can not be
1782 * processed but must be returned to the guest.
1783 */
1784 unsigned int virtqueue_drop_all(VirtQueue *vq)
1785 {
1786 struct VirtIODevice *vdev = vq->vdev;
1787
1788 if (virtio_device_disabled(vq->vdev)) {
1789 return 0;
1790 }
1791
1792 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
1793 return virtqueue_packed_drop_all(vq);
1794 } else {
1795 return virtqueue_split_drop_all(vq);
1796 }
1797 }
1798
1799 /* Reading and writing a structure directly to QEMUFile is *awful*, but
1800 * it is what QEMU has always done by mistake. We can change it sooner
1801 * or later by bumping the version number of the affected vm states.
1802 * In the meanwhile, since the in-memory layout of VirtQueueElement
1803 * has changed, we need to marshal to and from the layout that was
1804 * used before the change.
1805 */
1806 typedef struct VirtQueueElementOld {
1807 unsigned int index;
1808 unsigned int out_num;
1809 unsigned int in_num;
1810 hwaddr in_addr[VIRTQUEUE_MAX_SIZE];
1811 hwaddr out_addr[VIRTQUEUE_MAX_SIZE];
1812 struct iovec in_sg[VIRTQUEUE_MAX_SIZE];
1813 struct iovec out_sg[VIRTQUEUE_MAX_SIZE];
1814 } VirtQueueElementOld;
1815
1816 void *qemu_get_virtqueue_element(VirtIODevice *vdev, QEMUFile *f, size_t sz)
1817 {
1818 VirtQueueElement *elem;
1819 VirtQueueElementOld data;
1820 int i;
1821
1822 qemu_get_buffer(f, (uint8_t *)&data, sizeof(VirtQueueElementOld));
1823
1824 /* TODO: teach all callers that this can fail, and return failure instead
1825 * of asserting here.
1826 * This is just one thing (there are probably more) that must be
1827 * fixed before we can allow NDEBUG compilation.
1828 */
1829 assert(ARRAY_SIZE(data.in_addr) >= data.in_num);
1830 assert(ARRAY_SIZE(data.out_addr) >= data.out_num);
1831
1832 elem = virtqueue_alloc_element(sz, data.out_num, data.in_num);
1833 elem->index = data.index;
1834
1835 for (i = 0; i < elem->in_num; i++) {
1836 elem->in_addr[i] = data.in_addr[i];
1837 }
1838
1839 for (i = 0; i < elem->out_num; i++) {
1840 elem->out_addr[i] = data.out_addr[i];
1841 }
1842
1843 for (i = 0; i < elem->in_num; i++) {
1844 /* Base is overwritten by virtqueue_map. */
1845 elem->in_sg[i].iov_base = 0;
1846 elem->in_sg[i].iov_len = data.in_sg[i].iov_len;
1847 }
1848
1849 for (i = 0; i < elem->out_num; i++) {
1850 /* Base is overwritten by virtqueue_map. */
1851 elem->out_sg[i].iov_base = 0;
1852 elem->out_sg[i].iov_len = data.out_sg[i].iov_len;
1853 }
1854
1855 if (virtio_host_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
1856 qemu_get_be32s(f, &elem->ndescs);
1857 }
1858
1859 virtqueue_map(vdev, elem);
1860 return elem;
1861 }
1862
1863 void qemu_put_virtqueue_element(VirtIODevice *vdev, QEMUFile *f,
1864 VirtQueueElement *elem)
1865 {
1866 VirtQueueElementOld data;
1867 int i;
1868
1869 memset(&data, 0, sizeof(data));
1870 data.index = elem->index;
1871 data.in_num = elem->in_num;
1872 data.out_num = elem->out_num;
1873
1874 for (i = 0; i < elem->in_num; i++) {
1875 data.in_addr[i] = elem->in_addr[i];
1876 }
1877
1878 for (i = 0; i < elem->out_num; i++) {
1879 data.out_addr[i] = elem->out_addr[i];
1880 }
1881
1882 for (i = 0; i < elem->in_num; i++) {
1883 /* Base is overwritten by virtqueue_map when loading. Do not
1884 * save it, as it would leak the QEMU address space layout. */
1885 data.in_sg[i].iov_len = elem->in_sg[i].iov_len;
1886 }
1887
1888 for (i = 0; i < elem->out_num; i++) {
1889 /* Do not save iov_base as above. */
1890 data.out_sg[i].iov_len = elem->out_sg[i].iov_len;
1891 }
1892
1893 if (virtio_host_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
1894 qemu_put_be32s(f, &elem->ndescs);
1895 }
1896
1897 qemu_put_buffer(f, (uint8_t *)&data, sizeof(VirtQueueElementOld));
1898 }
1899
1900 /* virtio device */
1901 static void virtio_notify_vector(VirtIODevice *vdev, uint16_t vector)
1902 {
1903 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1904 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1905
1906 if (virtio_device_disabled(vdev)) {
1907 return;
1908 }
1909
1910 if (k->notify) {
1911 k->notify(qbus->parent, vector);
1912 }
1913 }
1914
1915 void virtio_update_irq(VirtIODevice *vdev)
1916 {
1917 virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
1918 }
1919
1920 static int virtio_validate_features(VirtIODevice *vdev)
1921 {
1922 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1923
1924 if (virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM) &&
1925 !virtio_vdev_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM)) {
1926 return -EFAULT;
1927 }
1928
1929 if (k->validate_features) {
1930 return k->validate_features(vdev);
1931 } else {
1932 return 0;
1933 }
1934 }
1935
1936 int virtio_set_status(VirtIODevice *vdev, uint8_t val)
1937 {
1938 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1939 trace_virtio_set_status(vdev, val);
1940
1941 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
1942 if (!(vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) &&
1943 val & VIRTIO_CONFIG_S_FEATURES_OK) {
1944 int ret = virtio_validate_features(vdev);
1945
1946 if (ret) {
1947 return ret;
1948 }
1949 }
1950 }
1951
1952 if ((vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) !=
1953 (val & VIRTIO_CONFIG_S_DRIVER_OK)) {
1954 virtio_set_started(vdev, val & VIRTIO_CONFIG_S_DRIVER_OK);
1955 }
1956
1957 if (k->set_status) {
1958 k->set_status(vdev, val);
1959 }
1960 vdev->status = val;
1961
1962 return 0;
1963 }
1964
1965 static enum virtio_device_endian virtio_default_endian(void)
1966 {
1967 if (target_words_bigendian()) {
1968 return VIRTIO_DEVICE_ENDIAN_BIG;
1969 } else {
1970 return VIRTIO_DEVICE_ENDIAN_LITTLE;
1971 }
1972 }
1973
1974 static enum virtio_device_endian virtio_current_cpu_endian(void)
1975 {
1976 CPUClass *cc = CPU_GET_CLASS(current_cpu);
1977
1978 if (cc->virtio_is_big_endian(current_cpu)) {
1979 return VIRTIO_DEVICE_ENDIAN_BIG;
1980 } else {
1981 return VIRTIO_DEVICE_ENDIAN_LITTLE;
1982 }
1983 }
1984
1985 void virtio_reset(void *opaque)
1986 {
1987 VirtIODevice *vdev = opaque;
1988 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1989 int i;
1990
1991 virtio_set_status(vdev, 0);
1992 if (current_cpu) {
1993 /* Guest initiated reset */
1994 vdev->device_endian = virtio_current_cpu_endian();
1995 } else {
1996 /* System reset */
1997 vdev->device_endian = virtio_default_endian();
1998 }
1999
2000 if (k->reset) {
2001 k->reset(vdev);
2002 }
2003
2004 vdev->start_on_kick = false;
2005 vdev->started = false;
2006 vdev->broken = false;
2007 vdev->guest_features = 0;
2008 vdev->queue_sel = 0;
2009 vdev->status = 0;
2010 vdev->disabled = false;
2011 qatomic_set(&vdev->isr, 0);
2012 vdev->config_vector = VIRTIO_NO_VECTOR;
2013 virtio_notify_vector(vdev, vdev->config_vector);
2014
2015 for(i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2016 vdev->vq[i].vring.desc = 0;
2017 vdev->vq[i].vring.avail = 0;
2018 vdev->vq[i].vring.used = 0;
2019 vdev->vq[i].last_avail_idx = 0;
2020 vdev->vq[i].shadow_avail_idx = 0;
2021 vdev->vq[i].used_idx = 0;
2022 vdev->vq[i].last_avail_wrap_counter = true;
2023 vdev->vq[i].shadow_avail_wrap_counter = true;
2024 vdev->vq[i].used_wrap_counter = true;
2025 virtio_queue_set_vector(vdev, i, VIRTIO_NO_VECTOR);
2026 vdev->vq[i].signalled_used = 0;
2027 vdev->vq[i].signalled_used_valid = false;
2028 vdev->vq[i].notification = true;
2029 vdev->vq[i].vring.num = vdev->vq[i].vring.num_default;
2030 vdev->vq[i].inuse = 0;
2031 virtio_virtqueue_reset_region_cache(&vdev->vq[i]);
2032 }
2033 }
2034
2035 uint32_t virtio_config_readb(VirtIODevice *vdev, uint32_t addr)
2036 {
2037 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2038 uint8_t val;
2039
2040 if (addr + sizeof(val) > vdev->config_len) {
2041 return (uint32_t)-1;
2042 }
2043
2044 k->get_config(vdev, vdev->config);
2045
2046 val = ldub_p(vdev->config + addr);
2047 return val;
2048 }
2049
2050 uint32_t virtio_config_readw(VirtIODevice *vdev, uint32_t addr)
2051 {
2052 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2053 uint16_t val;
2054
2055 if (addr + sizeof(val) > vdev->config_len) {
2056 return (uint32_t)-1;
2057 }
2058
2059 k->get_config(vdev, vdev->config);
2060
2061 val = lduw_p(vdev->config + addr);
2062 return val;
2063 }
2064
2065 uint32_t virtio_config_readl(VirtIODevice *vdev, uint32_t addr)
2066 {
2067 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2068 uint32_t val;
2069
2070 if (addr + sizeof(val) > vdev->config_len) {
2071 return (uint32_t)-1;
2072 }
2073
2074 k->get_config(vdev, vdev->config);
2075
2076 val = ldl_p(vdev->config + addr);
2077 return val;
2078 }
2079
2080 void virtio_config_writeb(VirtIODevice *vdev, uint32_t addr, uint32_t data)
2081 {
2082 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2083 uint8_t val = data;
2084
2085 if (addr + sizeof(val) > vdev->config_len) {
2086 return;
2087 }
2088
2089 stb_p(vdev->config + addr, val);
2090
2091 if (k->set_config) {
2092 k->set_config(vdev, vdev->config);
2093 }
2094 }
2095
2096 void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data)
2097 {
2098 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2099 uint16_t val = data;
2100
2101 if (addr + sizeof(val) > vdev->config_len) {
2102 return;
2103 }
2104
2105 stw_p(vdev->config + addr, val);
2106
2107 if (k->set_config) {
2108 k->set_config(vdev, vdev->config);
2109 }
2110 }
2111
2112 void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data)
2113 {
2114 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2115 uint32_t val = data;
2116
2117 if (addr + sizeof(val) > vdev->config_len) {
2118 return;
2119 }
2120
2121 stl_p(vdev->config + addr, val);
2122
2123 if (k->set_config) {
2124 k->set_config(vdev, vdev->config);
2125 }
2126 }
2127
2128 uint32_t virtio_config_modern_readb(VirtIODevice *vdev, uint32_t addr)
2129 {
2130 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2131 uint8_t val;
2132
2133 if (addr + sizeof(val) > vdev->config_len) {
2134 return (uint32_t)-1;
2135 }
2136
2137 k->get_config(vdev, vdev->config);
2138
2139 val = ldub_p(vdev->config + addr);
2140 return val;
2141 }
2142
2143 uint32_t virtio_config_modern_readw(VirtIODevice *vdev, uint32_t addr)
2144 {
2145 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2146 uint16_t val;
2147
2148 if (addr + sizeof(val) > vdev->config_len) {
2149 return (uint32_t)-1;
2150 }
2151
2152 k->get_config(vdev, vdev->config);
2153
2154 val = lduw_le_p(vdev->config + addr);
2155 return val;
2156 }
2157
2158 uint32_t virtio_config_modern_readl(VirtIODevice *vdev, uint32_t addr)
2159 {
2160 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2161 uint32_t val;
2162
2163 if (addr + sizeof(val) > vdev->config_len) {
2164 return (uint32_t)-1;
2165 }
2166
2167 k->get_config(vdev, vdev->config);
2168
2169 val = ldl_le_p(vdev->config + addr);
2170 return val;
2171 }
2172
2173 void virtio_config_modern_writeb(VirtIODevice *vdev,
2174 uint32_t addr, uint32_t data)
2175 {
2176 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2177 uint8_t val = data;
2178
2179 if (addr + sizeof(val) > vdev->config_len) {
2180 return;
2181 }
2182
2183 stb_p(vdev->config + addr, val);
2184
2185 if (k->set_config) {
2186 k->set_config(vdev, vdev->config);
2187 }
2188 }
2189
2190 void virtio_config_modern_writew(VirtIODevice *vdev,
2191 uint32_t addr, uint32_t data)
2192 {
2193 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2194 uint16_t val = data;
2195
2196 if (addr + sizeof(val) > vdev->config_len) {
2197 return;
2198 }
2199
2200 stw_le_p(vdev->config + addr, val);
2201
2202 if (k->set_config) {
2203 k->set_config(vdev, vdev->config);
2204 }
2205 }
2206
2207 void virtio_config_modern_writel(VirtIODevice *vdev,
2208 uint32_t addr, uint32_t data)
2209 {
2210 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2211 uint32_t val = data;
2212
2213 if (addr + sizeof(val) > vdev->config_len) {
2214 return;
2215 }
2216
2217 stl_le_p(vdev->config + addr, val);
2218
2219 if (k->set_config) {
2220 k->set_config(vdev, vdev->config);
2221 }
2222 }
2223
2224 void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr)
2225 {
2226 if (!vdev->vq[n].vring.num) {
2227 return;
2228 }
2229 vdev->vq[n].vring.desc = addr;
2230 virtio_queue_update_rings(vdev, n);
2231 }
2232
2233 hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n)
2234 {
2235 return vdev->vq[n].vring.desc;
2236 }
2237
2238 void virtio_queue_set_rings(VirtIODevice *vdev, int n, hwaddr desc,
2239 hwaddr avail, hwaddr used)
2240 {
2241 if (!vdev->vq[n].vring.num) {
2242 return;
2243 }
2244 vdev->vq[n].vring.desc = desc;
2245 vdev->vq[n].vring.avail = avail;
2246 vdev->vq[n].vring.used = used;
2247 virtio_init_region_cache(vdev, n);
2248 }
2249
2250 void virtio_queue_set_num(VirtIODevice *vdev, int n, int num)
2251 {
2252 /* Don't allow guest to flip queue between existent and
2253 * nonexistent states, or to set it to an invalid size.
2254 */
2255 if (!!num != !!vdev->vq[n].vring.num ||
2256 num > VIRTQUEUE_MAX_SIZE ||
2257 num < 0) {
2258 return;
2259 }
2260 vdev->vq[n].vring.num = num;
2261 }
2262
2263 VirtQueue *virtio_vector_first_queue(VirtIODevice *vdev, uint16_t vector)
2264 {
2265 return QLIST_FIRST(&vdev->vector_queues[vector]);
2266 }
2267
2268 VirtQueue *virtio_vector_next_queue(VirtQueue *vq)
2269 {
2270 return QLIST_NEXT(vq, node);
2271 }
2272
2273 int virtio_queue_get_num(VirtIODevice *vdev, int n)
2274 {
2275 return vdev->vq[n].vring.num;
2276 }
2277
2278 int virtio_queue_get_max_num(VirtIODevice *vdev, int n)
2279 {
2280 return vdev->vq[n].vring.num_default;
2281 }
2282
2283 int virtio_get_num_queues(VirtIODevice *vdev)
2284 {
2285 int i;
2286
2287 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2288 if (!virtio_queue_get_num(vdev, i)) {
2289 break;
2290 }
2291 }
2292
2293 return i;
2294 }
2295
2296 void virtio_queue_set_align(VirtIODevice *vdev, int n, int align)
2297 {
2298 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2299 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2300
2301 /* virtio-1 compliant devices cannot change the alignment */
2302 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
2303 error_report("tried to modify queue alignment for virtio-1 device");
2304 return;
2305 }
2306 /* Check that the transport told us it was going to do this
2307 * (so a buggy transport will immediately assert rather than
2308 * silently failing to migrate this state)
2309 */
2310 assert(k->has_variable_vring_alignment);
2311
2312 if (align) {
2313 vdev->vq[n].vring.align = align;
2314 virtio_queue_update_rings(vdev, n);
2315 }
2316 }
2317
2318 static bool virtio_queue_notify_aio_vq(VirtQueue *vq)
2319 {
2320 bool ret = false;
2321
2322 if (vq->vring.desc && vq->handle_aio_output) {
2323 VirtIODevice *vdev = vq->vdev;
2324
2325 trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
2326 ret = vq->handle_aio_output(vdev, vq);
2327
2328 if (unlikely(vdev->start_on_kick)) {
2329 virtio_set_started(vdev, true);
2330 }
2331 }
2332
2333 return ret;
2334 }
2335
2336 static void virtio_queue_notify_vq(VirtQueue *vq)
2337 {
2338 if (vq->vring.desc && vq->handle_output) {
2339 VirtIODevice *vdev = vq->vdev;
2340
2341 if (unlikely(vdev->broken)) {
2342 return;
2343 }
2344
2345 trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
2346 vq->handle_output(vdev, vq);
2347
2348 if (unlikely(vdev->start_on_kick)) {
2349 virtio_set_started(vdev, true);
2350 }
2351 }
2352 }
2353
2354 void virtio_queue_notify(VirtIODevice *vdev, int n)
2355 {
2356 VirtQueue *vq = &vdev->vq[n];
2357
2358 if (unlikely(!vq->vring.desc || vdev->broken)) {
2359 return;
2360 }
2361
2362 trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
2363 if (vq->host_notifier_enabled) {
2364 event_notifier_set(&vq->host_notifier);
2365 } else if (vq->handle_output) {
2366 vq->handle_output(vdev, vq);
2367
2368 if (unlikely(vdev->start_on_kick)) {
2369 virtio_set_started(vdev, true);
2370 }
2371 }
2372 }
2373
2374 uint16_t virtio_queue_vector(VirtIODevice *vdev, int n)
2375 {
2376 return n < VIRTIO_QUEUE_MAX ? vdev->vq[n].vector :
2377 VIRTIO_NO_VECTOR;
2378 }
2379
2380 void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector)
2381 {
2382 VirtQueue *vq = &vdev->vq[n];
2383
2384 if (n < VIRTIO_QUEUE_MAX) {
2385 if (vdev->vector_queues &&
2386 vdev->vq[n].vector != VIRTIO_NO_VECTOR) {
2387 QLIST_REMOVE(vq, node);
2388 }
2389 vdev->vq[n].vector = vector;
2390 if (vdev->vector_queues &&
2391 vector != VIRTIO_NO_VECTOR) {
2392 QLIST_INSERT_HEAD(&vdev->vector_queues[vector], vq, node);
2393 }
2394 }
2395 }
2396
2397 VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,
2398 VirtIOHandleOutput handle_output)
2399 {
2400 int i;
2401
2402 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2403 if (vdev->vq[i].vring.num == 0)
2404 break;
2405 }
2406
2407 if (i == VIRTIO_QUEUE_MAX || queue_size > VIRTQUEUE_MAX_SIZE)
2408 abort();
2409
2410 vdev->vq[i].vring.num = queue_size;
2411 vdev->vq[i].vring.num_default = queue_size;
2412 vdev->vq[i].vring.align = VIRTIO_PCI_VRING_ALIGN;
2413 vdev->vq[i].handle_output = handle_output;
2414 vdev->vq[i].handle_aio_output = NULL;
2415 vdev->vq[i].used_elems = g_malloc0(sizeof(VirtQueueElement) *
2416 queue_size);
2417
2418 return &vdev->vq[i];
2419 }
2420
2421 void virtio_delete_queue(VirtQueue *vq)
2422 {
2423 vq->vring.num = 0;
2424 vq->vring.num_default = 0;
2425 vq->handle_output = NULL;
2426 vq->handle_aio_output = NULL;
2427 g_free(vq->used_elems);
2428 vq->used_elems = NULL;
2429 virtio_virtqueue_reset_region_cache(vq);
2430 }
2431
2432 void virtio_del_queue(VirtIODevice *vdev, int n)
2433 {
2434 if (n < 0 || n >= VIRTIO_QUEUE_MAX) {
2435 abort();
2436 }
2437
2438 virtio_delete_queue(&vdev->vq[n]);
2439 }
2440
2441 static void virtio_set_isr(VirtIODevice *vdev, int value)
2442 {
2443 uint8_t old = qatomic_read(&vdev->isr);
2444
2445 /* Do not write ISR if it does not change, so that its cacheline remains
2446 * shared in the common case where the guest does not read it.
2447 */
2448 if ((old & value) != value) {
2449 qatomic_or(&vdev->isr, value);
2450 }
2451 }
2452
2453 static bool virtio_split_should_notify(VirtIODevice *vdev, VirtQueue *vq)
2454 {
2455 uint16_t old, new;
2456 bool v;
2457 /* We need to expose used array entries before checking used event. */
2458 smp_mb();
2459 /* Always notify when queue is empty (when feature acknowledge) */
2460 if (virtio_vdev_has_feature(vdev, VIRTIO_F_NOTIFY_ON_EMPTY) &&
2461 !vq->inuse && virtio_queue_empty(vq)) {
2462 return true;
2463 }
2464
2465 if (!virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
2466 return !(vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT);
2467 }
2468
2469 v = vq->signalled_used_valid;
2470 vq->signalled_used_valid = true;
2471 old = vq->signalled_used;
2472 new = vq->signalled_used = vq->used_idx;
2473 return !v || vring_need_event(vring_get_used_event(vq), new, old);
2474 }
2475
2476 static bool vring_packed_need_event(VirtQueue *vq, bool wrap,
2477 uint16_t off_wrap, uint16_t new,
2478 uint16_t old)
2479 {
2480 int off = off_wrap & ~(1 << 15);
2481
2482 if (wrap != off_wrap >> 15) {
2483 off -= vq->vring.num;
2484 }
2485
2486 return vring_need_event(off, new, old);
2487 }
2488
2489 static bool virtio_packed_should_notify(VirtIODevice *vdev, VirtQueue *vq)
2490 {
2491 VRingPackedDescEvent e;
2492 uint16_t old, new;
2493 bool v;
2494 VRingMemoryRegionCaches *caches;
2495
2496 caches = vring_get_region_caches(vq);
2497 if (!caches) {
2498 return false;
2499 }
2500
2501 vring_packed_event_read(vdev, &caches->avail, &e);
2502
2503 old = vq->signalled_used;
2504 new = vq->signalled_used = vq->used_idx;
2505 v = vq->signalled_used_valid;
2506 vq->signalled_used_valid = true;
2507
2508 if (e.flags == VRING_PACKED_EVENT_FLAG_DISABLE) {
2509 return false;
2510 } else if (e.flags == VRING_PACKED_EVENT_FLAG_ENABLE) {
2511 return true;
2512 }
2513
2514 return !v || vring_packed_need_event(vq, vq->used_wrap_counter,
2515 e.off_wrap, new, old);
2516 }
2517
2518 /* Called within rcu_read_lock(). */
2519 static bool virtio_should_notify(VirtIODevice *vdev, VirtQueue *vq)
2520 {
2521 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
2522 return virtio_packed_should_notify(vdev, vq);
2523 } else {
2524 return virtio_split_should_notify(vdev, vq);
2525 }
2526 }
2527
2528 void virtio_notify_irqfd(VirtIODevice *vdev, VirtQueue *vq)
2529 {
2530 WITH_RCU_READ_LOCK_GUARD() {
2531 if (!virtio_should_notify(vdev, vq)) {
2532 return;
2533 }
2534 }
2535
2536 trace_virtio_notify_irqfd(vdev, vq);
2537
2538 /*
2539 * virtio spec 1.0 says ISR bit 0 should be ignored with MSI, but
2540 * windows drivers included in virtio-win 1.8.0 (circa 2015) are
2541 * incorrectly polling this bit during crashdump and hibernation
2542 * in MSI mode, causing a hang if this bit is never updated.
2543 * Recent releases of Windows do not really shut down, but rather
2544 * log out and hibernate to make the next startup faster. Hence,
2545 * this manifested as a more serious hang during shutdown with
2546 *
2547 * Next driver release from 2016 fixed this problem, so working around it
2548 * is not a must, but it's easy to do so let's do it here.
2549 *
2550 * Note: it's safe to update ISR from any thread as it was switched
2551 * to an atomic operation.
2552 */
2553 virtio_set_isr(vq->vdev, 0x1);
2554 event_notifier_set(&vq->guest_notifier);
2555 }
2556
2557 static void virtio_irq(VirtQueue *vq)
2558 {
2559 virtio_set_isr(vq->vdev, 0x1);
2560 virtio_notify_vector(vq->vdev, vq->vector);
2561 }
2562
2563 void virtio_notify(VirtIODevice *vdev, VirtQueue *vq)
2564 {
2565 WITH_RCU_READ_LOCK_GUARD() {
2566 if (!virtio_should_notify(vdev, vq)) {
2567 return;
2568 }
2569 }
2570
2571 trace_virtio_notify(vdev, vq);
2572 virtio_irq(vq);
2573 }
2574
2575 void virtio_notify_config(VirtIODevice *vdev)
2576 {
2577 if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK))
2578 return;
2579
2580 virtio_set_isr(vdev, 0x3);
2581 vdev->generation++;
2582 virtio_notify_vector(vdev, vdev->config_vector);
2583 }
2584
2585 static bool virtio_device_endian_needed(void *opaque)
2586 {
2587 VirtIODevice *vdev = opaque;
2588
2589 assert(vdev->device_endian != VIRTIO_DEVICE_ENDIAN_UNKNOWN);
2590 if (!virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
2591 return vdev->device_endian != virtio_default_endian();
2592 }
2593 /* Devices conforming to VIRTIO 1.0 or later are always LE. */
2594 return vdev->device_endian != VIRTIO_DEVICE_ENDIAN_LITTLE;
2595 }
2596
2597 static bool virtio_64bit_features_needed(void *opaque)
2598 {
2599 VirtIODevice *vdev = opaque;
2600
2601 return (vdev->host_features >> 32) != 0;
2602 }
2603
2604 static bool virtio_virtqueue_needed(void *opaque)
2605 {
2606 VirtIODevice *vdev = opaque;
2607
2608 return virtio_host_has_feature(vdev, VIRTIO_F_VERSION_1);
2609 }
2610
2611 static bool virtio_packed_virtqueue_needed(void *opaque)
2612 {
2613 VirtIODevice *vdev = opaque;
2614
2615 return virtio_host_has_feature(vdev, VIRTIO_F_RING_PACKED);
2616 }
2617
2618 static bool virtio_ringsize_needed(void *opaque)
2619 {
2620 VirtIODevice *vdev = opaque;
2621 int i;
2622
2623 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2624 if (vdev->vq[i].vring.num != vdev->vq[i].vring.num_default) {
2625 return true;
2626 }
2627 }
2628 return false;
2629 }
2630
2631 static bool virtio_extra_state_needed(void *opaque)
2632 {
2633 VirtIODevice *vdev = opaque;
2634 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2635 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2636
2637 return k->has_extra_state &&
2638 k->has_extra_state(qbus->parent);
2639 }
2640
2641 static bool virtio_broken_needed(void *opaque)
2642 {
2643 VirtIODevice *vdev = opaque;
2644
2645 return vdev->broken;
2646 }
2647
2648 static bool virtio_started_needed(void *opaque)
2649 {
2650 VirtIODevice *vdev = opaque;
2651
2652 return vdev->started;
2653 }
2654
2655 static bool virtio_disabled_needed(void *opaque)
2656 {
2657 VirtIODevice *vdev = opaque;
2658
2659 return vdev->disabled;
2660 }
2661
2662 static const VMStateDescription vmstate_virtqueue = {
2663 .name = "virtqueue_state",
2664 .version_id = 1,
2665 .minimum_version_id = 1,
2666 .fields = (VMStateField[]) {
2667 VMSTATE_UINT64(vring.avail, struct VirtQueue),
2668 VMSTATE_UINT64(vring.used, struct VirtQueue),
2669 VMSTATE_END_OF_LIST()
2670 }
2671 };
2672
2673 static const VMStateDescription vmstate_packed_virtqueue = {
2674 .name = "packed_virtqueue_state",
2675 .version_id = 1,
2676 .minimum_version_id = 1,
2677 .fields = (VMStateField[]) {
2678 VMSTATE_UINT16(last_avail_idx, struct VirtQueue),
2679 VMSTATE_BOOL(last_avail_wrap_counter, struct VirtQueue),
2680 VMSTATE_UINT16(used_idx, struct VirtQueue),
2681 VMSTATE_BOOL(used_wrap_counter, struct VirtQueue),
2682 VMSTATE_UINT32(inuse, struct VirtQueue),
2683 VMSTATE_END_OF_LIST()
2684 }
2685 };
2686
2687 static const VMStateDescription vmstate_virtio_virtqueues = {
2688 .name = "virtio/virtqueues",
2689 .version_id = 1,
2690 .minimum_version_id = 1,
2691 .needed = &virtio_virtqueue_needed,
2692 .fields = (VMStateField[]) {
2693 VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice,
2694 VIRTIO_QUEUE_MAX, 0, vmstate_virtqueue, VirtQueue),
2695 VMSTATE_END_OF_LIST()
2696 }
2697 };
2698
2699 static const VMStateDescription vmstate_virtio_packed_virtqueues = {
2700 .name = "virtio/packed_virtqueues",
2701 .version_id = 1,
2702 .minimum_version_id = 1,
2703 .needed = &virtio_packed_virtqueue_needed,
2704 .fields = (VMStateField[]) {
2705 VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice,
2706 VIRTIO_QUEUE_MAX, 0, vmstate_packed_virtqueue, VirtQueue),
2707 VMSTATE_END_OF_LIST()
2708 }
2709 };
2710
2711 static const VMStateDescription vmstate_ringsize = {
2712 .name = "ringsize_state",
2713 .version_id = 1,
2714 .minimum_version_id = 1,
2715 .fields = (VMStateField[]) {
2716 VMSTATE_UINT32(vring.num_default, struct VirtQueue),
2717 VMSTATE_END_OF_LIST()
2718 }
2719 };
2720
2721 static const VMStateDescription vmstate_virtio_ringsize = {
2722 .name = "virtio/ringsize",
2723 .version_id = 1,
2724 .minimum_version_id = 1,
2725 .needed = &virtio_ringsize_needed,
2726 .fields = (VMStateField[]) {
2727 VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice,
2728 VIRTIO_QUEUE_MAX, 0, vmstate_ringsize, VirtQueue),
2729 VMSTATE_END_OF_LIST()
2730 }
2731 };
2732
2733 static int get_extra_state(QEMUFile *f, void *pv, size_t size,
2734 const VMStateField *field)
2735 {
2736 VirtIODevice *vdev = pv;
2737 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2738 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2739
2740 if (!k->load_extra_state) {
2741 return -1;
2742 } else {
2743 return k->load_extra_state(qbus->parent, f);
2744 }
2745 }
2746
2747 static int put_extra_state(QEMUFile *f, void *pv, size_t size,
2748 const VMStateField *field, QJSON *vmdesc)
2749 {
2750 VirtIODevice *vdev = pv;
2751 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2752 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2753
2754 k->save_extra_state(qbus->parent, f);
2755 return 0;
2756 }
2757
2758 static const VMStateInfo vmstate_info_extra_state = {
2759 .name = "virtqueue_extra_state",
2760 .get = get_extra_state,
2761 .put = put_extra_state,
2762 };
2763
2764 static const VMStateDescription vmstate_virtio_extra_state = {
2765 .name = "virtio/extra_state",
2766 .version_id = 1,
2767 .minimum_version_id = 1,
2768 .needed = &virtio_extra_state_needed,
2769 .fields = (VMStateField[]) {
2770 {
2771 .name = "extra_state",
2772 .version_id = 0,
2773 .field_exists = NULL,
2774 .size = 0,
2775 .info = &vmstate_info_extra_state,
2776 .flags = VMS_SINGLE,
2777 .offset = 0,
2778 },
2779 VMSTATE_END_OF_LIST()
2780 }
2781 };
2782
2783 static const VMStateDescription vmstate_virtio_device_endian = {
2784 .name = "virtio/device_endian",
2785 .version_id = 1,
2786 .minimum_version_id = 1,
2787 .needed = &virtio_device_endian_needed,
2788 .fields = (VMStateField[]) {
2789 VMSTATE_UINT8(device_endian, VirtIODevice),
2790 VMSTATE_END_OF_LIST()
2791 }
2792 };
2793
2794 static const VMStateDescription vmstate_virtio_64bit_features = {
2795 .name = "virtio/64bit_features",
2796 .version_id = 1,
2797 .minimum_version_id = 1,
2798 .needed = &virtio_64bit_features_needed,
2799 .fields = (VMStateField[]) {
2800 VMSTATE_UINT64(guest_features, VirtIODevice),
2801 VMSTATE_END_OF_LIST()
2802 }
2803 };
2804
2805 static const VMStateDescription vmstate_virtio_broken = {
2806 .name = "virtio/broken",
2807 .version_id = 1,
2808 .minimum_version_id = 1,
2809 .needed = &virtio_broken_needed,
2810 .fields = (VMStateField[]) {
2811 VMSTATE_BOOL(broken, VirtIODevice),
2812 VMSTATE_END_OF_LIST()
2813 }
2814 };
2815
2816 static const VMStateDescription vmstate_virtio_started = {
2817 .name = "virtio/started",
2818 .version_id = 1,
2819 .minimum_version_id = 1,
2820 .needed = &virtio_started_needed,
2821 .fields = (VMStateField[]) {
2822 VMSTATE_BOOL(started, VirtIODevice),
2823 VMSTATE_END_OF_LIST()
2824 }
2825 };
2826
2827 static const VMStateDescription vmstate_virtio_disabled = {
2828 .name = "virtio/disabled",
2829 .version_id = 1,
2830 .minimum_version_id = 1,
2831 .needed = &virtio_disabled_needed,
2832 .fields = (VMStateField[]) {
2833 VMSTATE_BOOL(disabled, VirtIODevice),
2834 VMSTATE_END_OF_LIST()
2835 }
2836 };
2837
2838 static const VMStateDescription vmstate_virtio = {
2839 .name = "virtio",
2840 .version_id = 1,
2841 .minimum_version_id = 1,
2842 .minimum_version_id_old = 1,
2843 .fields = (VMStateField[]) {
2844 VMSTATE_END_OF_LIST()
2845 },
2846 .subsections = (const VMStateDescription*[]) {
2847 &vmstate_virtio_device_endian,
2848 &vmstate_virtio_64bit_features,
2849 &vmstate_virtio_virtqueues,
2850 &vmstate_virtio_ringsize,
2851 &vmstate_virtio_broken,
2852 &vmstate_virtio_extra_state,
2853 &vmstate_virtio_started,
2854 &vmstate_virtio_packed_virtqueues,
2855 &vmstate_virtio_disabled,
2856 NULL
2857 }
2858 };
2859
2860 int virtio_save(VirtIODevice *vdev, QEMUFile *f)
2861 {
2862 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2863 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2864 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
2865 uint32_t guest_features_lo = (vdev->guest_features & 0xffffffff);
2866 int i;
2867
2868 if (k->save_config) {
2869 k->save_config(qbus->parent, f);
2870 }
2871
2872 qemu_put_8s(f, &vdev->status);
2873 qemu_put_8s(f, &vdev->isr);
2874 qemu_put_be16s(f, &vdev->queue_sel);
2875 qemu_put_be32s(f, &guest_features_lo);
2876 qemu_put_be32(f, vdev->config_len);
2877 qemu_put_buffer(f, vdev->config, vdev->config_len);
2878
2879 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2880 if (vdev->vq[i].vring.num == 0)
2881 break;
2882 }
2883
2884 qemu_put_be32(f, i);
2885
2886 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2887 if (vdev->vq[i].vring.num == 0)
2888 break;
2889
2890 qemu_put_be32(f, vdev->vq[i].vring.num);
2891 if (k->has_variable_vring_alignment) {
2892 qemu_put_be32(f, vdev->vq[i].vring.align);
2893 }
2894 /*
2895 * Save desc now, the rest of the ring addresses are saved in
2896 * subsections for VIRTIO-1 devices.
2897 */
2898 qemu_put_be64(f, vdev->vq[i].vring.desc);
2899 qemu_put_be16s(f, &vdev->vq[i].last_avail_idx);
2900 if (k->save_queue) {
2901 k->save_queue(qbus->parent, i, f);
2902 }
2903 }
2904
2905 if (vdc->save != NULL) {
2906 vdc->save(vdev, f);
2907 }
2908
2909 if (vdc->vmsd) {
2910 int ret = vmstate_save_state(f, vdc->vmsd, vdev, NULL);
2911 if (ret) {
2912 return ret;
2913 }
2914 }
2915
2916 /* Subsections */
2917 return vmstate_save_state(f, &vmstate_virtio, vdev, NULL);
2918 }
2919
2920 /* A wrapper for use as a VMState .put function */
2921 static int virtio_device_put(QEMUFile *f, void *opaque, size_t size,
2922 const VMStateField *field, QJSON *vmdesc)
2923 {
2924 return virtio_save(VIRTIO_DEVICE(opaque), f);
2925 }
2926
2927 /* A wrapper for use as a VMState .get function */
2928 static int virtio_device_get(QEMUFile *f, void *opaque, size_t size,
2929 const VMStateField *field)
2930 {
2931 VirtIODevice *vdev = VIRTIO_DEVICE(opaque);
2932 DeviceClass *dc = DEVICE_CLASS(VIRTIO_DEVICE_GET_CLASS(vdev));
2933
2934 return virtio_load(vdev, f, dc->vmsd->version_id);
2935 }
2936
2937 const VMStateInfo virtio_vmstate_info = {
2938 .name = "virtio",
2939 .get = virtio_device_get,
2940 .put = virtio_device_put,
2941 };
2942
2943 static int virtio_set_features_nocheck(VirtIODevice *vdev, uint64_t val)
2944 {
2945 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2946 bool bad = (val & ~(vdev->host_features)) != 0;
2947
2948 val &= vdev->host_features;
2949 if (k->set_features) {
2950 k->set_features(vdev, val);
2951 }
2952 vdev->guest_features = val;
2953 return bad ? -1 : 0;
2954 }
2955
2956 int virtio_set_features(VirtIODevice *vdev, uint64_t val)
2957 {
2958 int ret;
2959 /*
2960 * The driver must not attempt to set features after feature negotiation
2961 * has finished.
2962 */
2963 if (vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) {
2964 return -EINVAL;
2965 }
2966 ret = virtio_set_features_nocheck(vdev, val);
2967 if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
2968 /* VIRTIO_RING_F_EVENT_IDX changes the size of the caches. */
2969 int i;
2970 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2971 if (vdev->vq[i].vring.num != 0) {
2972 virtio_init_region_cache(vdev, i);
2973 }
2974 }
2975 }
2976 if (!ret) {
2977 if (!virtio_device_started(vdev, vdev->status) &&
2978 !virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
2979 vdev->start_on_kick = true;
2980 }
2981 }
2982 return ret;
2983 }
2984
2985 size_t virtio_feature_get_config_size(VirtIOFeature *feature_sizes,
2986 uint64_t host_features)
2987 {
2988 size_t config_size = 0;
2989 int i;
2990
2991 for (i = 0; feature_sizes[i].flags != 0; i++) {
2992 if (host_features & feature_sizes[i].flags) {
2993 config_size = MAX(feature_sizes[i].end, config_size);
2994 }
2995 }
2996
2997 return config_size;
2998 }
2999
3000 int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id)
3001 {
3002 int i, ret;
3003 int32_t config_len;
3004 uint32_t num;
3005 uint32_t features;
3006 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3007 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
3008 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
3009
3010 /*
3011 * We poison the endianness to ensure it does not get used before
3012 * subsections have been loaded.
3013 */
3014 vdev->device_endian = VIRTIO_DEVICE_ENDIAN_UNKNOWN;
3015
3016 if (k->load_config) {
3017 ret = k->load_config(qbus->parent, f);
3018 if (ret)
3019 return ret;
3020 }
3021
3022 qemu_get_8s(f, &vdev->status);
3023 qemu_get_8s(f, &vdev->isr);
3024 qemu_get_be16s(f, &vdev->queue_sel);
3025 if (vdev->queue_sel >= VIRTIO_QUEUE_MAX) {
3026 return -1;
3027 }
3028 qemu_get_be32s(f, &features);
3029
3030 /*
3031 * Temporarily set guest_features low bits - needed by
3032 * virtio net load code testing for VIRTIO_NET_F_CTRL_GUEST_OFFLOADS
3033 * VIRTIO_NET_F_GUEST_ANNOUNCE and VIRTIO_NET_F_CTRL_VQ.
3034 *
3035 * Note: devices should always test host features in future - don't create
3036 * new dependencies like this.
3037 */
3038 vdev->guest_features = features;
3039
3040 config_len = qemu_get_be32(f);
3041
3042 /*
3043 * There are cases where the incoming config can be bigger or smaller
3044 * than what we have; so load what we have space for, and skip
3045 * any excess that's in the stream.
3046 */
3047 qemu_get_buffer(f, vdev->config, MIN(config_len, vdev->config_len));
3048
3049 while (config_len > vdev->config_len) {
3050 qemu_get_byte(f);
3051 config_len--;
3052 }
3053
3054 num = qemu_get_be32(f);
3055
3056 if (num > VIRTIO_QUEUE_MAX) {
3057 error_report("Invalid number of virtqueues: 0x%x", num);
3058 return -1;
3059 }
3060
3061 for (i = 0; i < num; i++) {
3062 vdev->vq[i].vring.num = qemu_get_be32(f);
3063 if (k->has_variable_vring_alignment) {
3064 vdev->vq[i].vring.align = qemu_get_be32(f);
3065 }
3066 vdev->vq[i].vring.desc = qemu_get_be64(f);
3067 qemu_get_be16s(f, &vdev->vq[i].last_avail_idx);
3068 vdev->vq[i].signalled_used_valid = false;
3069 vdev->vq[i].notification = true;
3070
3071 if (!vdev->vq[i].vring.desc && vdev->vq[i].last_avail_idx) {
3072 error_report("VQ %d address 0x0 "
3073 "inconsistent with Host index 0x%x",
3074 i, vdev->vq[i].last_avail_idx);
3075 return -1;
3076 }
3077 if (k->load_queue) {
3078 ret = k->load_queue(qbus->parent, i, f);
3079 if (ret)
3080 return ret;
3081 }
3082 }
3083
3084 virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
3085
3086 if (vdc->load != NULL) {
3087 ret = vdc->load(vdev, f, version_id);
3088 if (ret) {
3089 return ret;
3090 }
3091 }
3092
3093 if (vdc->vmsd) {
3094 ret = vmstate_load_state(f, vdc->vmsd, vdev, version_id);
3095 if (ret) {
3096 return ret;
3097 }
3098 }
3099
3100 /* Subsections */
3101 ret = vmstate_load_state(f, &vmstate_virtio, vdev, 1);
3102 if (ret) {
3103 return ret;
3104 }
3105
3106 if (vdev->device_endian == VIRTIO_DEVICE_ENDIAN_UNKNOWN) {
3107 vdev->device_endian = virtio_default_endian();
3108 }
3109
3110 if (virtio_64bit_features_needed(vdev)) {
3111 /*
3112 * Subsection load filled vdev->guest_features. Run them
3113 * through virtio_set_features to sanity-check them against
3114 * host_features.
3115 */
3116 uint64_t features64 = vdev->guest_features;
3117 if (virtio_set_features_nocheck(vdev, features64) < 0) {
3118 error_report("Features 0x%" PRIx64 " unsupported. "
3119 "Allowed features: 0x%" PRIx64,
3120 features64, vdev->host_features);
3121 return -1;
3122 }
3123 } else {
3124 if (virtio_set_features_nocheck(vdev, features) < 0) {
3125 error_report("Features 0x%x unsupported. "
3126 "Allowed features: 0x%" PRIx64,
3127 features, vdev->host_features);
3128 return -1;
3129 }
3130 }
3131
3132 if (!virtio_device_started(vdev, vdev->status) &&
3133 !virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
3134 vdev->start_on_kick = true;
3135 }
3136
3137 RCU_READ_LOCK_GUARD();
3138 for (i = 0; i < num; i++) {
3139 if (vdev->vq[i].vring.desc) {
3140 uint16_t nheads;
3141
3142 /*
3143 * VIRTIO-1 devices migrate desc, used, and avail ring addresses so
3144 * only the region cache needs to be set up. Legacy devices need
3145 * to calculate used and avail ring addresses based on the desc
3146 * address.
3147 */
3148 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
3149 virtio_init_region_cache(vdev, i);
3150 } else {
3151 virtio_queue_update_rings(vdev, i);
3152 }
3153
3154 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3155 vdev->vq[i].shadow_avail_idx = vdev->vq[i].last_avail_idx;
3156 vdev->vq[i].shadow_avail_wrap_counter =
3157 vdev->vq[i].last_avail_wrap_counter;
3158 continue;
3159 }
3160
3161 nheads = vring_avail_idx(&vdev->vq[i]) - vdev->vq[i].last_avail_idx;
3162 /* Check it isn't doing strange things with descriptor numbers. */
3163 if (nheads > vdev->vq[i].vring.num) {
3164 qemu_log_mask(LOG_GUEST_ERROR,
3165 "VQ %d size 0x%x Guest index 0x%x "
3166 "inconsistent with Host index 0x%x: delta 0x%x",
3167 i, vdev->vq[i].vring.num,
3168 vring_avail_idx(&vdev->vq[i]),
3169 vdev->vq[i].last_avail_idx, nheads);
3170 }
3171 vdev->vq[i].used_idx = vring_used_idx(&vdev->vq[i]);
3172 vdev->vq[i].shadow_avail_idx = vring_avail_idx(&vdev->vq[i]);
3173
3174 /*
3175 * Some devices migrate VirtQueueElements that have been popped
3176 * from the avail ring but not yet returned to the used ring.
3177 * Since max ring size < UINT16_MAX it's safe to use modulo
3178 * UINT16_MAX + 1 subtraction.
3179 */
3180 vdev->vq[i].inuse = (uint16_t)(vdev->vq[i].last_avail_idx -
3181 vdev->vq[i].used_idx);
3182 if (vdev->vq[i].inuse > vdev->vq[i].vring.num) {
3183 error_report("VQ %d size 0x%x < last_avail_idx 0x%x - "
3184 "used_idx 0x%x",
3185 i, vdev->vq[i].vring.num,
3186 vdev->vq[i].last_avail_idx,
3187 vdev->vq[i].used_idx);
3188 return -1;
3189 }
3190 }
3191 }
3192
3193 if (vdc->post_load) {
3194 ret = vdc->post_load(vdev);
3195 if (ret) {
3196 return ret;
3197 }
3198 }
3199
3200 return 0;
3201 }
3202
3203 void virtio_cleanup(VirtIODevice *vdev)
3204 {
3205 qemu_del_vm_change_state_handler(vdev->vmstate);
3206 }
3207
3208 static void virtio_vmstate_change(void *opaque, int running, RunState state)
3209 {
3210 VirtIODevice *vdev = opaque;
3211 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3212 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
3213 bool backend_run = running && virtio_device_started(vdev, vdev->status);
3214 vdev->vm_running = running;
3215
3216 if (backend_run) {
3217 virtio_set_status(vdev, vdev->status);
3218 }
3219
3220 if (k->vmstate_change) {
3221 k->vmstate_change(qbus->parent, backend_run);
3222 }
3223
3224 if (!backend_run) {
3225 virtio_set_status(vdev, vdev->status);
3226 }
3227 }
3228
3229 void virtio_instance_init_common(Object *proxy_obj, void *data,
3230 size_t vdev_size, const char *vdev_name)
3231 {
3232 DeviceState *vdev = data;
3233
3234 object_initialize_child_with_props(proxy_obj, "virtio-backend", vdev,
3235 vdev_size, vdev_name, &error_abort,
3236 NULL);
3237 qdev_alias_all_properties(vdev, proxy_obj);
3238 }
3239
3240 void virtio_init(VirtIODevice *vdev, const char *name,
3241 uint16_t device_id, size_t config_size)
3242 {
3243 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3244 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
3245 int i;
3246 int nvectors = k->query_nvectors ? k->query_nvectors(qbus->parent) : 0;
3247
3248 if (nvectors) {
3249 vdev->vector_queues =
3250 g_malloc0(sizeof(*vdev->vector_queues) * nvectors);
3251 }
3252
3253 vdev->start_on_kick = false;
3254 vdev->started = false;
3255 vdev->device_id = device_id;
3256 vdev->status = 0;
3257 qatomic_set(&vdev->isr, 0);
3258 vdev->queue_sel = 0;
3259 vdev->config_vector = VIRTIO_NO_VECTOR;
3260 vdev->vq = g_malloc0(sizeof(VirtQueue) * VIRTIO_QUEUE_MAX);
3261 vdev->vm_running = runstate_is_running();
3262 vdev->broken = false;
3263 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
3264 vdev->vq[i].vector = VIRTIO_NO_VECTOR;
3265 vdev->vq[i].vdev = vdev;
3266 vdev->vq[i].queue_index = i;
3267 vdev->vq[i].host_notifier_enabled = false;
3268 }
3269
3270 vdev->name = name;
3271 vdev->config_len = config_size;
3272 if (vdev->config_len) {
3273 vdev->config = g_malloc0(config_size);
3274 } else {
3275 vdev->config = NULL;
3276 }
3277 vdev->vmstate = qdev_add_vm_change_state_handler(DEVICE(vdev),
3278 virtio_vmstate_change, vdev);
3279 vdev->device_endian = virtio_default_endian();
3280 vdev->use_guest_notifier_mask = true;
3281 }
3282
3283 /*
3284 * Only devices that have already been around prior to defining the virtio
3285 * standard support legacy mode; this includes devices not specified in the
3286 * standard. All newer devices conform to the virtio standard only.
3287 */
3288 bool virtio_legacy_allowed(VirtIODevice *vdev)
3289 {
3290 switch (vdev->device_id) {
3291 case VIRTIO_ID_NET:
3292 case VIRTIO_ID_BLOCK:
3293 case VIRTIO_ID_CONSOLE:
3294 case VIRTIO_ID_RNG:
3295 case VIRTIO_ID_BALLOON:
3296 case VIRTIO_ID_RPMSG:
3297 case VIRTIO_ID_SCSI:
3298 case VIRTIO_ID_9P:
3299 case VIRTIO_ID_RPROC_SERIAL:
3300 case VIRTIO_ID_CAIF:
3301 return true;
3302 default:
3303 return false;
3304 }
3305 }
3306
3307 bool virtio_legacy_check_disabled(VirtIODevice *vdev)
3308 {
3309 return vdev->disable_legacy_check;
3310 }
3311
3312 hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n)
3313 {
3314 return vdev->vq[n].vring.desc;
3315 }
3316
3317 bool virtio_queue_enabled_legacy(VirtIODevice *vdev, int n)
3318 {
3319 return virtio_queue_get_desc_addr(vdev, n) != 0;
3320 }
3321
3322 bool virtio_queue_enabled(VirtIODevice *vdev, int n)
3323 {
3324 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3325 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
3326
3327 if (k->queue_enabled) {
3328 return k->queue_enabled(qbus->parent, n);
3329 }
3330 return virtio_queue_enabled_legacy(vdev, n);
3331 }
3332
3333 hwaddr virtio_queue_get_avail_addr(VirtIODevice *vdev, int n)
3334 {
3335 return vdev->vq[n].vring.avail;
3336 }
3337
3338 hwaddr virtio_queue_get_used_addr(VirtIODevice *vdev, int n)
3339 {
3340 return vdev->vq[n].vring.used;
3341 }
3342
3343 hwaddr virtio_queue_get_desc_size(VirtIODevice *vdev, int n)
3344 {
3345 return sizeof(VRingDesc) * vdev->vq[n].vring.num;
3346 }
3347
3348 hwaddr virtio_queue_get_avail_size(VirtIODevice *vdev, int n)
3349 {
3350 int s;
3351
3352 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3353 return sizeof(struct VRingPackedDescEvent);
3354 }
3355
3356 s = virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
3357 return offsetof(VRingAvail, ring) +
3358 sizeof(uint16_t) * vdev->vq[n].vring.num + s;
3359 }
3360
3361 hwaddr virtio_queue_get_used_size(VirtIODevice *vdev, int n)
3362 {
3363 int s;
3364
3365 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3366 return sizeof(struct VRingPackedDescEvent);
3367 }
3368
3369 s = virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
3370 return offsetof(VRingUsed, ring) +
3371 sizeof(VRingUsedElem) * vdev->vq[n].vring.num + s;
3372 }
3373
3374 static unsigned int virtio_queue_packed_get_last_avail_idx(VirtIODevice *vdev,
3375 int n)
3376 {
3377 unsigned int avail, used;
3378
3379 avail = vdev->vq[n].last_avail_idx;
3380 avail |= ((uint16_t)vdev->vq[n].last_avail_wrap_counter) << 15;
3381
3382 used = vdev->vq[n].used_idx;
3383 used |= ((uint16_t)vdev->vq[n].used_wrap_counter) << 15;
3384
3385 return avail | used << 16;
3386 }
3387
3388 static uint16_t virtio_queue_split_get_last_avail_idx(VirtIODevice *vdev,
3389 int n)
3390 {
3391 return vdev->vq[n].last_avail_idx;
3392 }
3393
3394 unsigned int virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n)
3395 {
3396 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3397 return virtio_queue_packed_get_last_avail_idx(vdev, n);
3398 } else {
3399 return virtio_queue_split_get_last_avail_idx(vdev, n);
3400 }
3401 }
3402
3403 static void virtio_queue_packed_set_last_avail_idx(VirtIODevice *vdev,
3404 int n, unsigned int idx)
3405 {
3406 struct VirtQueue *vq = &vdev->vq[n];
3407
3408 vq->last_avail_idx = vq->shadow_avail_idx = idx & 0x7fff;
3409 vq->last_avail_wrap_counter =
3410 vq->shadow_avail_wrap_counter = !!(idx & 0x8000);
3411 idx >>= 16;
3412 vq->used_idx = idx & 0x7ffff;
3413 vq->used_wrap_counter = !!(idx & 0x8000);
3414 }
3415
3416 static void virtio_queue_split_set_last_avail_idx(VirtIODevice *vdev,
3417 int n, unsigned int idx)
3418 {
3419 vdev->vq[n].last_avail_idx = idx;
3420 vdev->vq[n].shadow_avail_idx = idx;
3421 }
3422
3423 void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n,
3424 unsigned int idx)
3425 {
3426 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3427 virtio_queue_packed_set_last_avail_idx(vdev, n, idx);
3428 } else {
3429 virtio_queue_split_set_last_avail_idx(vdev, n, idx);
3430 }
3431 }
3432
3433 static void virtio_queue_packed_restore_last_avail_idx(VirtIODevice *vdev,
3434 int n)
3435 {
3436 /* We don't have a reference like avail idx in shared memory */
3437 return;
3438 }
3439
3440 static void virtio_queue_split_restore_last_avail_idx(VirtIODevice *vdev,
3441 int n)
3442 {
3443 RCU_READ_LOCK_GUARD();
3444 if (vdev->vq[n].vring.desc) {
3445 vdev->vq[n].last_avail_idx = vring_used_idx(&vdev->vq[n]);
3446 vdev->vq[n].shadow_avail_idx = vdev->vq[n].last_avail_idx;
3447 }
3448 }
3449
3450 void virtio_queue_restore_last_avail_idx(VirtIODevice *vdev, int n)
3451 {
3452 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3453 virtio_queue_packed_restore_last_avail_idx(vdev, n);
3454 } else {
3455 virtio_queue_split_restore_last_avail_idx(vdev, n);
3456 }
3457 }
3458
3459 static void virtio_queue_packed_update_used_idx(VirtIODevice *vdev, int n)
3460 {
3461 /* used idx was updated through set_last_avail_idx() */
3462 return;
3463 }
3464
3465 static void virtio_split_packed_update_used_idx(VirtIODevice *vdev, int n)
3466 {
3467 RCU_READ_LOCK_GUARD();
3468 if (vdev->vq[n].vring.desc) {
3469 vdev->vq[n].used_idx = vring_used_idx(&vdev->vq[n]);
3470 }
3471 }
3472
3473 void virtio_queue_update_used_idx(VirtIODevice *vdev, int n)
3474 {
3475 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3476 return virtio_queue_packed_update_used_idx(vdev, n);
3477 } else {
3478 return virtio_split_packed_update_used_idx(vdev, n);
3479 }
3480 }
3481
3482 void virtio_queue_invalidate_signalled_used(VirtIODevice *vdev, int n)
3483 {
3484 vdev->vq[n].signalled_used_valid = false;
3485 }
3486
3487 VirtQueue *virtio_get_queue(VirtIODevice *vdev, int n)
3488 {
3489 return vdev->vq + n;
3490 }
3491
3492 uint16_t virtio_get_queue_index(VirtQueue *vq)
3493 {
3494 return vq->queue_index;
3495 }
3496
3497 static void virtio_queue_guest_notifier_read(EventNotifier *n)
3498 {
3499 VirtQueue *vq = container_of(n, VirtQueue, guest_notifier);
3500 if (event_notifier_test_and_clear(n)) {
3501 virtio_irq(vq);
3502 }
3503 }
3504
3505 void virtio_queue_set_guest_notifier_fd_handler(VirtQueue *vq, bool assign,
3506 bool with_irqfd)
3507 {
3508 if (assign && !with_irqfd) {
3509 event_notifier_set_handler(&vq->guest_notifier,
3510 virtio_queue_guest_notifier_read);
3511 } else {
3512 event_notifier_set_handler(&vq->guest_notifier, NULL);
3513 }
3514 if (!assign) {
3515 /* Test and clear notifier before closing it,
3516 * in case poll callback didn't have time to run. */
3517 virtio_queue_guest_notifier_read(&vq->guest_notifier);
3518 }
3519 }
3520
3521 EventNotifier *virtio_queue_get_guest_notifier(VirtQueue *vq)
3522 {
3523 return &vq->guest_notifier;
3524 }
3525
3526 static void virtio_queue_host_notifier_aio_read(EventNotifier *n)
3527 {
3528 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
3529 if (event_notifier_test_and_clear(n)) {
3530 virtio_queue_notify_aio_vq(vq);
3531 }
3532 }
3533
3534 static void virtio_queue_host_notifier_aio_poll_begin(EventNotifier *n)
3535 {
3536 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
3537
3538 virtio_queue_set_notification(vq, 0);
3539 }
3540
3541 static bool virtio_queue_host_notifier_aio_poll(void *opaque)
3542 {
3543 EventNotifier *n = opaque;
3544 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
3545
3546 if (!vq->vring.desc || virtio_queue_empty(vq)) {
3547 return false;
3548 }
3549
3550 return virtio_queue_notify_aio_vq(vq);
3551 }
3552
3553 static void virtio_queue_host_notifier_aio_poll_end(EventNotifier *n)
3554 {
3555 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
3556
3557 /* Caller polls once more after this to catch requests that race with us */
3558 virtio_queue_set_notification(vq, 1);
3559 }
3560
3561 void virtio_queue_aio_set_host_notifier_handler(VirtQueue *vq, AioContext *ctx,
3562 VirtIOHandleAIOOutput handle_output)
3563 {
3564 if (handle_output) {
3565 vq->handle_aio_output = handle_output;
3566 aio_set_event_notifier(ctx, &vq->host_notifier, true,
3567 virtio_queue_host_notifier_aio_read,
3568 virtio_queue_host_notifier_aio_poll);
3569 aio_set_event_notifier_poll(ctx, &vq->host_notifier,
3570 virtio_queue_host_notifier_aio_poll_begin,
3571 virtio_queue_host_notifier_aio_poll_end);
3572 } else {
3573 aio_set_event_notifier(ctx, &vq->host_notifier, true, NULL, NULL);
3574 /* Test and clear notifier before after disabling event,
3575 * in case poll callback didn't have time to run. */
3576 virtio_queue_host_notifier_aio_read(&vq->host_notifier);
3577 vq->handle_aio_output = NULL;
3578 }
3579 }
3580
3581 void virtio_queue_host_notifier_read(EventNotifier *n)
3582 {
3583 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
3584 if (event_notifier_test_and_clear(n)) {
3585 virtio_queue_notify_vq(vq);
3586 }
3587 }
3588
3589 EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq)
3590 {
3591 return &vq->host_notifier;
3592 }
3593
3594 void virtio_queue_set_host_notifier_enabled(VirtQueue *vq, bool enabled)
3595 {
3596 vq->host_notifier_enabled = enabled;
3597 }
3598
3599 int virtio_queue_set_host_notifier_mr(VirtIODevice *vdev, int n,
3600 MemoryRegion *mr, bool assign)
3601 {
3602 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3603 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
3604
3605 if (k->set_host_notifier_mr) {
3606 return k->set_host_notifier_mr(qbus->parent, n, mr, assign);
3607 }
3608
3609 return -1;
3610 }
3611
3612 void virtio_device_set_child_bus_name(VirtIODevice *vdev, char *bus_name)
3613 {
3614 g_free(vdev->bus_name);
3615 vdev->bus_name = g_strdup(bus_name);
3616 }
3617
3618 void GCC_FMT_ATTR(2, 3) virtio_error(VirtIODevice *vdev, const char *fmt, ...)
3619 {
3620 va_list ap;
3621
3622 va_start(ap, fmt);
3623 error_vreport(fmt, ap);
3624 va_end(ap);
3625
3626 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
3627 vdev->status = vdev->status | VIRTIO_CONFIG_S_NEEDS_RESET;
3628 virtio_notify_config(vdev);
3629 }
3630
3631 vdev->broken = true;
3632 }
3633
3634 static void virtio_memory_listener_commit(MemoryListener *listener)
3635 {
3636 VirtIODevice *vdev = container_of(listener, VirtIODevice, listener);
3637 int i;
3638
3639 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
3640 if (vdev->vq[i].vring.num == 0) {
3641 break;
3642 }
3643 virtio_init_region_cache(vdev, i);
3644 }
3645 }
3646
3647 static void virtio_device_realize(DeviceState *dev, Error **errp)
3648 {
3649 VirtIODevice *vdev = VIRTIO_DEVICE(dev);
3650 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev);
3651 Error *err = NULL;
3652
3653 /* Devices should either use vmsd or the load/save methods */
3654 assert(!vdc->vmsd || !vdc->load);
3655
3656 if (vdc->realize != NULL) {
3657 vdc->realize(dev, &err);
3658 if (err != NULL) {
3659 error_propagate(errp, err);
3660 return;
3661 }
3662 }
3663
3664 virtio_bus_device_plugged(vdev, &err);
3665 if (err != NULL) {
3666 error_propagate(errp, err);
3667 vdc->unrealize(dev);
3668 return;
3669 }
3670
3671 vdev->listener.commit = virtio_memory_listener_commit;
3672 memory_listener_register(&vdev->listener, vdev->dma_as);
3673 }
3674
3675 static void virtio_device_unrealize(DeviceState *dev)
3676 {
3677 VirtIODevice *vdev = VIRTIO_DEVICE(dev);
3678 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev);
3679
3680 virtio_bus_device_unplugged(vdev);
3681
3682 if (vdc->unrealize != NULL) {
3683 vdc->unrealize(dev);
3684 }
3685
3686 g_free(vdev->bus_name);
3687 vdev->bus_name = NULL;
3688 }
3689
3690 static void virtio_device_free_virtqueues(VirtIODevice *vdev)
3691 {
3692 int i;
3693 if (!vdev->vq) {
3694 return;
3695 }
3696
3697 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
3698 if (vdev->vq[i].vring.num == 0) {
3699 break;
3700 }
3701 virtio_virtqueue_reset_region_cache(&vdev->vq[i]);
3702 }
3703 g_free(vdev->vq);
3704 }
3705
3706 static void virtio_device_instance_finalize(Object *obj)
3707 {
3708 VirtIODevice *vdev = VIRTIO_DEVICE(obj);
3709
3710 memory_listener_unregister(&vdev->listener);
3711 virtio_device_free_virtqueues(vdev);
3712
3713 g_free(vdev->config);
3714 g_free(vdev->vector_queues);
3715 }
3716
3717 static Property virtio_properties[] = {
3718 DEFINE_VIRTIO_COMMON_FEATURES(VirtIODevice, host_features),
3719 DEFINE_PROP_BOOL("use-started", VirtIODevice, use_started, true),
3720 DEFINE_PROP_BOOL("use-disabled-flag", VirtIODevice, use_disabled_flag, true),
3721 DEFINE_PROP_BOOL("x-disable-legacy-check", VirtIODevice,
3722 disable_legacy_check, false),
3723 DEFINE_PROP_END_OF_LIST(),
3724 };
3725
3726 static int virtio_device_start_ioeventfd_impl(VirtIODevice *vdev)
3727 {
3728 VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev)));
3729 int i, n, r, err;
3730
3731 memory_region_transaction_begin();
3732 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
3733 VirtQueue *vq = &vdev->vq[n];
3734 if (!virtio_queue_get_num(vdev, n)) {
3735 continue;
3736 }
3737 r = virtio_bus_set_host_notifier(qbus, n, true);
3738 if (r < 0) {
3739 err = r;
3740 goto assign_error;
3741 }
3742 event_notifier_set_handler(&vq->host_notifier,
3743 virtio_queue_host_notifier_read);
3744 }
3745
3746 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
3747 /* Kick right away to begin processing requests already in vring */
3748 VirtQueue *vq = &vdev->vq[n];
3749 if (!vq->vring.num) {
3750 continue;
3751 }
3752 event_notifier_set(&vq->host_notifier);
3753 }
3754 memory_region_transaction_commit();
3755 return 0;
3756
3757 assign_error:
3758 i = n; /* save n for a second iteration after transaction is committed. */
3759 while (--n >= 0) {
3760 VirtQueue *vq = &vdev->vq[n];
3761 if (!virtio_queue_get_num(vdev, n)) {
3762 continue;
3763 }
3764
3765 event_notifier_set_handler(&vq->host_notifier, NULL);
3766 r = virtio_bus_set_host_notifier(qbus, n, false);
3767 assert(r >= 0);
3768 }
3769 memory_region_transaction_commit();
3770
3771 while (--i >= 0) {
3772 if (!virtio_queue_get_num(vdev, i)) {
3773 continue;
3774 }
3775 virtio_bus_cleanup_host_notifier(qbus, i);
3776 }
3777 return err;
3778 }
3779
3780 int virtio_device_start_ioeventfd(VirtIODevice *vdev)
3781 {
3782 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3783 VirtioBusState *vbus = VIRTIO_BUS(qbus);
3784
3785 return virtio_bus_start_ioeventfd(vbus);
3786 }
3787
3788 static void virtio_device_stop_ioeventfd_impl(VirtIODevice *vdev)
3789 {
3790 VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev)));
3791 int n, r;
3792
3793 memory_region_transaction_begin();
3794 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
3795 VirtQueue *vq = &vdev->vq[n];
3796
3797 if (!virtio_queue_get_num(vdev, n)) {
3798 continue;
3799 }
3800 event_notifier_set_handler(&vq->host_notifier, NULL);
3801 r = virtio_bus_set_host_notifier(qbus, n, false);
3802 assert(r >= 0);
3803 }
3804 memory_region_transaction_commit();
3805
3806 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
3807 if (!virtio_queue_get_num(vdev, n)) {
3808 continue;
3809 }
3810 virtio_bus_cleanup_host_notifier(qbus, n);
3811 }
3812 }
3813
3814 int virtio_device_grab_ioeventfd(VirtIODevice *vdev)
3815 {
3816 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3817 VirtioBusState *vbus = VIRTIO_BUS(qbus);
3818
3819 return virtio_bus_grab_ioeventfd(vbus);
3820 }
3821
3822 void virtio_device_release_ioeventfd(VirtIODevice *vdev)
3823 {
3824 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3825 VirtioBusState *vbus = VIRTIO_BUS(qbus);
3826
3827 virtio_bus_release_ioeventfd(vbus);
3828 }
3829
3830 static void virtio_device_class_init(ObjectClass *klass, void *data)
3831 {
3832 /* Set the default value here. */
3833 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
3834 DeviceClass *dc = DEVICE_CLASS(klass);
3835
3836 dc->realize = virtio_device_realize;
3837 dc->unrealize = virtio_device_unrealize;
3838 dc->bus_type = TYPE_VIRTIO_BUS;
3839 device_class_set_props(dc, virtio_properties);
3840 vdc->start_ioeventfd = virtio_device_start_ioeventfd_impl;
3841 vdc->stop_ioeventfd = virtio_device_stop_ioeventfd_impl;
3842
3843 vdc->legacy_features |= VIRTIO_LEGACY_FEATURES;
3844 }
3845
3846 bool virtio_device_ioeventfd_enabled(VirtIODevice *vdev)
3847 {
3848 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3849 VirtioBusState *vbus = VIRTIO_BUS(qbus);
3850
3851 return virtio_bus_ioeventfd_enabled(vbus);
3852 }
3853
3854 static const TypeInfo virtio_device_info = {
3855 .name = TYPE_VIRTIO_DEVICE,
3856 .parent = TYPE_DEVICE,
3857 .instance_size = sizeof(VirtIODevice),
3858 .class_init = virtio_device_class_init,
3859 .instance_finalize = virtio_device_instance_finalize,
3860 .abstract = true,
3861 .class_size = sizeof(VirtioDeviceClass),
3862 };
3863
3864 static void virtio_register_types(void)
3865 {
3866 type_register_static(&virtio_device_info);
3867 }
3868
3869 type_init(virtio_register_types)
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