?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
qapi: fix example of dump-guest-memory
[qemu/armbru.git] / hw / virtio / virtio.c
blob9d637e043e6b50025b61f612f63190449177f786
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 "qemu/error-report.h"
19 #include "qemu/log.h"
20 #include "qemu/main-loop.h"
21 #include "qemu/module.h"
22 #include "hw/virtio/virtio.h"
23 #include "migration/qemu-file-types.h"
24 #include "qemu/atomic.h"
25 #include "hw/virtio/virtio-bus.h"
26 #include "hw/qdev-properties.h"
27 #include "hw/virtio/virtio-access.h"
28 #include "sysemu/dma.h"
29 #include "sysemu/runstate.h"
30 #include "standard-headers/linux/virtio_ids.h"
31
32 /*
33 * The alignment to use between consumer and producer parts of vring.
34 * x86 pagesize again. This is the default, used by transports like PCI
35 * which don't provide a means for the guest to tell the host the alignment.
36 */
37 #define VIRTIO_PCI_VRING_ALIGN 4096
38
39 typedef struct VRingDesc
40 {
41 uint64_t addr;
42 uint32_t len;
43 uint16_t flags;
44 uint16_t next;
45 } VRingDesc;
46
47 typedef struct VRingPackedDesc {
48 uint64_t addr;
49 uint32_t len;
50 uint16_t id;
51 uint16_t flags;
52 } VRingPackedDesc;
53
54 typedef struct VRingAvail
55 {
56 uint16_t flags;
57 uint16_t idx;
58 uint16_t ring[];
59 } VRingAvail;
60
61 typedef struct VRingUsedElem
62 {
63 uint32_t id;
64 uint32_t len;
65 } VRingUsedElem;
66
67 typedef struct VRingUsed
68 {
69 uint16_t flags;
70 uint16_t idx;
71 VRingUsedElem ring[];
72 } VRingUsed;
73
74 typedef struct VRingMemoryRegionCaches {
75 struct rcu_head rcu;
76 MemoryRegionCache desc;
77 MemoryRegionCache avail;
78 MemoryRegionCache used;
79 } VRingMemoryRegionCaches;
80
81 typedef struct VRing
82 {
83 unsigned int num;
84 unsigned int num_default;
85 unsigned int align;
86 hwaddr desc;
87 hwaddr avail;
88 hwaddr used;
89 VRingMemoryRegionCaches *caches;
90 } VRing;
91
92 typedef struct VRingPackedDescEvent {
93 uint16_t off_wrap;
94 uint16_t flags;
95 } VRingPackedDescEvent ;
96
97 struct VirtQueue
98 {
99 VRing vring;
100 VirtQueueElement *used_elems;
101
102 /* Next head to pop */
103 uint16_t last_avail_idx;
104 bool last_avail_wrap_counter;
105
106 /* Last avail_idx read from VQ. */
107 uint16_t shadow_avail_idx;
108 bool shadow_avail_wrap_counter;
109
110 uint16_t used_idx;
111 bool used_wrap_counter;
112
113 /* Last used index value we have signalled on */
114 uint16_t signalled_used;
115
116 /* Last used index value we have signalled on */
117 bool signalled_used_valid;
118
119 /* Notification enabled? */
120 bool notification;
121
122 uint16_t queue_index;
123
124 unsigned int inuse;
125
126 uint16_t vector;
127 VirtIOHandleOutput handle_output;
128 VirtIODevice *vdev;
129 EventNotifier guest_notifier;
130 EventNotifier host_notifier;
131 bool host_notifier_enabled;
132 QLIST_ENTRY(VirtQueue) node;
133 };
134
135 /* Called within call_rcu(). */
136 static void virtio_free_region_cache(VRingMemoryRegionCaches *caches)
137 {
138 assert(caches != NULL);
139 address_space_cache_destroy(&caches->desc);
140 address_space_cache_destroy(&caches->avail);
141 address_space_cache_destroy(&caches->used);
142 g_free(caches);
143 }
144
145 static void virtio_virtqueue_reset_region_cache(struct VirtQueue *vq)
146 {
147 VRingMemoryRegionCaches *caches;
148
149 caches = qatomic_read(&vq->vring.caches);
150 qatomic_rcu_set(&vq->vring.caches, NULL);
151 if (caches) {
152 call_rcu(caches, virtio_free_region_cache, rcu);
153 }
154 }
155
156 static void virtio_init_region_cache(VirtIODevice *vdev, int n)
157 {
158 VirtQueue *vq = &vdev->vq[n];
159 VRingMemoryRegionCaches *old = vq->vring.caches;
160 VRingMemoryRegionCaches *new = NULL;
161 hwaddr addr, size;
162 int64_t len;
163 bool packed;
164
165
166 addr = vq->vring.desc;
167 if (!addr) {
168 goto out_no_cache;
169 }
170 new = g_new0(VRingMemoryRegionCaches, 1);
171 size = virtio_queue_get_desc_size(vdev, n);
172 packed = virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED) ?
173 true : false;
174 len = address_space_cache_init(&new->desc, vdev->dma_as,
175 addr, size, packed);
176 if (len < size) {
177 virtio_error(vdev, "Cannot map desc");
178 goto err_desc;
179 }
180
181 size = virtio_queue_get_used_size(vdev, n);
182 len = address_space_cache_init(&new->used, vdev->dma_as,
183 vq->vring.used, size, true);
184 if (len < size) {
185 virtio_error(vdev, "Cannot map used");
186 goto err_used;
187 }
188
189 size = virtio_queue_get_avail_size(vdev, n);
190 len = address_space_cache_init(&new->avail, vdev->dma_as,
191 vq->vring.avail, size, false);
192 if (len < size) {
193 virtio_error(vdev, "Cannot map avail");
194 goto err_avail;
195 }
196
197 qatomic_rcu_set(&vq->vring.caches, new);
198 if (old) {
199 call_rcu(old, virtio_free_region_cache, rcu);
200 }
201 return;
202
203 err_avail:
204 address_space_cache_destroy(&new->avail);
205 err_used:
206 address_space_cache_destroy(&new->used);
207 err_desc:
208 address_space_cache_destroy(&new->desc);
209 out_no_cache:
210 g_free(new);
211 virtio_virtqueue_reset_region_cache(vq);
212 }
213
214 /* virt queue functions */
215 void virtio_queue_update_rings(VirtIODevice *vdev, int n)
216 {
217 VRing *vring = &vdev->vq[n].vring;
218
219 if (!vring->num || !vring->desc || !vring->align) {
220 /* not yet setup -> nothing to do */
221 return;
222 }
223 vring->avail = vring->desc + vring->num * sizeof(VRingDesc);
224 vring->used = vring_align(vring->avail +
225 offsetof(VRingAvail, ring[vring->num]),
226 vring->align);
227 virtio_init_region_cache(vdev, n);
228 }
229
230 /* Called within rcu_read_lock(). */
231 static void vring_split_desc_read(VirtIODevice *vdev, VRingDesc *desc,
232 MemoryRegionCache *cache, int i)
233 {
234 address_space_read_cached(cache, i * sizeof(VRingDesc),
235 desc, sizeof(VRingDesc));
236 virtio_tswap64s(vdev, &desc->addr);
237 virtio_tswap32s(vdev, &desc->len);
238 virtio_tswap16s(vdev, &desc->flags);
239 virtio_tswap16s(vdev, &desc->next);
240 }
241
242 static void vring_packed_event_read(VirtIODevice *vdev,
243 MemoryRegionCache *cache,
244 VRingPackedDescEvent *e)
245 {
246 hwaddr off_off = offsetof(VRingPackedDescEvent, off_wrap);
247 hwaddr off_flags = offsetof(VRingPackedDescEvent, flags);
248
249 e->flags = virtio_lduw_phys_cached(vdev, cache, off_flags);
250 /* Make sure flags is seen before off_wrap */
251 smp_rmb();
252 e->off_wrap = virtio_lduw_phys_cached(vdev, cache, off_off);
253 virtio_tswap16s(vdev, &e->flags);
254 }
255
256 static void vring_packed_off_wrap_write(VirtIODevice *vdev,
257 MemoryRegionCache *cache,
258 uint16_t off_wrap)
259 {
260 hwaddr off = offsetof(VRingPackedDescEvent, off_wrap);
261
262 virtio_stw_phys_cached(vdev, cache, off, off_wrap);
263 address_space_cache_invalidate(cache, off, sizeof(off_wrap));
264 }
265
266 static void vring_packed_flags_write(VirtIODevice *vdev,
267 MemoryRegionCache *cache, uint16_t flags)
268 {
269 hwaddr off = offsetof(VRingPackedDescEvent, flags);
270
271 virtio_stw_phys_cached(vdev, cache, off, flags);
272 address_space_cache_invalidate(cache, off, sizeof(flags));
273 }
274
275 /* Called within rcu_read_lock(). */
276 static VRingMemoryRegionCaches *vring_get_region_caches(struct VirtQueue *vq)
277 {
278 return qatomic_rcu_read(&vq->vring.caches);
279 }
280
281 /* Called within rcu_read_lock(). */
282 static inline uint16_t vring_avail_flags(VirtQueue *vq)
283 {
284 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
285 hwaddr pa = offsetof(VRingAvail, flags);
286
287 if (!caches) {
288 return 0;
289 }
290
291 return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
292 }
293
294 /* Called within rcu_read_lock(). */
295 static inline uint16_t vring_avail_idx(VirtQueue *vq)
296 {
297 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
298 hwaddr pa = offsetof(VRingAvail, idx);
299
300 if (!caches) {
301 return 0;
302 }
303
304 vq->shadow_avail_idx = virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
305 return vq->shadow_avail_idx;
306 }
307
308 /* Called within rcu_read_lock(). */
309 static inline uint16_t vring_avail_ring(VirtQueue *vq, int i)
310 {
311 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
312 hwaddr pa = offsetof(VRingAvail, ring[i]);
313
314 if (!caches) {
315 return 0;
316 }
317
318 return virtio_lduw_phys_cached(vq->vdev, &caches->avail, pa);
319 }
320
321 /* Called within rcu_read_lock(). */
322 static inline uint16_t vring_get_used_event(VirtQueue *vq)
323 {
324 return vring_avail_ring(vq, vq->vring.num);
325 }
326
327 /* Called within rcu_read_lock(). */
328 static inline void vring_used_write(VirtQueue *vq, VRingUsedElem *uelem,
329 int i)
330 {
331 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
332 hwaddr pa = offsetof(VRingUsed, ring[i]);
333
334 if (!caches) {
335 return;
336 }
337
338 virtio_tswap32s(vq->vdev, &uelem->id);
339 virtio_tswap32s(vq->vdev, &uelem->len);
340 address_space_write_cached(&caches->used, pa, uelem, sizeof(VRingUsedElem));
341 address_space_cache_invalidate(&caches->used, pa, sizeof(VRingUsedElem));
342 }
343
344 /* Called within rcu_read_lock(). */
345 static uint16_t vring_used_idx(VirtQueue *vq)
346 {
347 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
348 hwaddr pa = offsetof(VRingUsed, idx);
349
350 if (!caches) {
351 return 0;
352 }
353
354 return virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
355 }
356
357 /* Called within rcu_read_lock(). */
358 static inline void vring_used_idx_set(VirtQueue *vq, uint16_t val)
359 {
360 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
361 hwaddr pa = offsetof(VRingUsed, idx);
362
363 if (caches) {
364 virtio_stw_phys_cached(vq->vdev, &caches->used, pa, val);
365 address_space_cache_invalidate(&caches->used, pa, sizeof(val));
366 }
367
368 vq->used_idx = val;
369 }
370
371 /* Called within rcu_read_lock(). */
372 static inline void vring_used_flags_set_bit(VirtQueue *vq, int mask)
373 {
374 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
375 VirtIODevice *vdev = vq->vdev;
376 hwaddr pa = offsetof(VRingUsed, flags);
377 uint16_t flags;
378
379 if (!caches) {
380 return;
381 }
382
383 flags = virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
384 virtio_stw_phys_cached(vdev, &caches->used, pa, flags | mask);
385 address_space_cache_invalidate(&caches->used, pa, sizeof(flags));
386 }
387
388 /* Called within rcu_read_lock(). */
389 static inline void vring_used_flags_unset_bit(VirtQueue *vq, int mask)
390 {
391 VRingMemoryRegionCaches *caches = vring_get_region_caches(vq);
392 VirtIODevice *vdev = vq->vdev;
393 hwaddr pa = offsetof(VRingUsed, flags);
394 uint16_t flags;
395
396 if (!caches) {
397 return;
398 }
399
400 flags = virtio_lduw_phys_cached(vq->vdev, &caches->used, pa);
401 virtio_stw_phys_cached(vdev, &caches->used, pa, flags & ~mask);
402 address_space_cache_invalidate(&caches->used, pa, sizeof(flags));
403 }
404
405 /* Called within rcu_read_lock(). */
406 static inline void vring_set_avail_event(VirtQueue *vq, uint16_t val)
407 {
408 VRingMemoryRegionCaches *caches;
409 hwaddr pa;
410 if (!vq->notification) {
411 return;
412 }
413
414 caches = vring_get_region_caches(vq);
415 if (!caches) {
416 return;
417 }
418
419 pa = offsetof(VRingUsed, ring[vq->vring.num]);
420 virtio_stw_phys_cached(vq->vdev, &caches->used, pa, val);
421 address_space_cache_invalidate(&caches->used, pa, sizeof(val));
422 }
423
424 static void virtio_queue_split_set_notification(VirtQueue *vq, int enable)
425 {
426 RCU_READ_LOCK_GUARD();
427
428 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
429 vring_set_avail_event(vq, vring_avail_idx(vq));
430 } else if (enable) {
431 vring_used_flags_unset_bit(vq, VRING_USED_F_NO_NOTIFY);
432 } else {
433 vring_used_flags_set_bit(vq, VRING_USED_F_NO_NOTIFY);
434 }
435 if (enable) {
436 /* Expose avail event/used flags before caller checks the avail idx. */
437 smp_mb();
438 }
439 }
440
441 static void virtio_queue_packed_set_notification(VirtQueue *vq, int enable)
442 {
443 uint16_t off_wrap;
444 VRingPackedDescEvent e;
445 VRingMemoryRegionCaches *caches;
446
447 RCU_READ_LOCK_GUARD();
448 caches = vring_get_region_caches(vq);
449 if (!caches) {
450 return;
451 }
452
453 vring_packed_event_read(vq->vdev, &caches->used, &e);
454
455 if (!enable) {
456 e.flags = VRING_PACKED_EVENT_FLAG_DISABLE;
457 } else if (virtio_vdev_has_feature(vq->vdev, VIRTIO_RING_F_EVENT_IDX)) {
458 off_wrap = vq->shadow_avail_idx | vq->shadow_avail_wrap_counter << 15;
459 vring_packed_off_wrap_write(vq->vdev, &caches->used, off_wrap);
460 /* Make sure off_wrap is wrote before flags */
461 smp_wmb();
462 e.flags = VRING_PACKED_EVENT_FLAG_DESC;
463 } else {
464 e.flags = VRING_PACKED_EVENT_FLAG_ENABLE;
465 }
466
467 vring_packed_flags_write(vq->vdev, &caches->used, e.flags);
468 if (enable) {
469 /* Expose avail event/used flags before caller checks the avail idx. */
470 smp_mb();
471 }
472 }
473
474 bool virtio_queue_get_notification(VirtQueue *vq)
475 {
476 return vq->notification;
477 }
478
479 void virtio_queue_set_notification(VirtQueue *vq, int enable)
480 {
481 vq->notification = enable;
482
483 if (!vq->vring.desc) {
484 return;
485 }
486
487 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
488 virtio_queue_packed_set_notification(vq, enable);
489 } else {
490 virtio_queue_split_set_notification(vq, enable);
491 }
492 }
493
494 int virtio_queue_ready(VirtQueue *vq)
495 {
496 return vq->vring.avail != 0;
497 }
498
499 static void vring_packed_desc_read_flags(VirtIODevice *vdev,
500 uint16_t *flags,
501 MemoryRegionCache *cache,
502 int i)
503 {
504 hwaddr off = i * sizeof(VRingPackedDesc) + offsetof(VRingPackedDesc, flags);
505
506 *flags = virtio_lduw_phys_cached(vdev, cache, off);
507 }
508
509 static void vring_packed_desc_read(VirtIODevice *vdev,
510 VRingPackedDesc *desc,
511 MemoryRegionCache *cache,
512 int i, bool strict_order)
513 {
514 hwaddr off = i * sizeof(VRingPackedDesc);
515
516 vring_packed_desc_read_flags(vdev, &desc->flags, cache, i);
517
518 if (strict_order) {
519 /* Make sure flags is read before the rest fields. */
520 smp_rmb();
521 }
522
523 address_space_read_cached(cache, off + offsetof(VRingPackedDesc, addr),
524 &desc->addr, sizeof(desc->addr));
525 address_space_read_cached(cache, off + offsetof(VRingPackedDesc, id),
526 &desc->id, sizeof(desc->id));
527 address_space_read_cached(cache, off + offsetof(VRingPackedDesc, len),
528 &desc->len, sizeof(desc->len));
529 virtio_tswap64s(vdev, &desc->addr);
530 virtio_tswap16s(vdev, &desc->id);
531 virtio_tswap32s(vdev, &desc->len);
532 }
533
534 static void vring_packed_desc_write_data(VirtIODevice *vdev,
535 VRingPackedDesc *desc,
536 MemoryRegionCache *cache,
537 int i)
538 {
539 hwaddr off_id = i * sizeof(VRingPackedDesc) +
540 offsetof(VRingPackedDesc, id);
541 hwaddr off_len = i * sizeof(VRingPackedDesc) +
542 offsetof(VRingPackedDesc, len);
543
544 virtio_tswap32s(vdev, &desc->len);
545 virtio_tswap16s(vdev, &desc->id);
546 address_space_write_cached(cache, off_id, &desc->id, sizeof(desc->id));
547 address_space_cache_invalidate(cache, off_id, sizeof(desc->id));
548 address_space_write_cached(cache, off_len, &desc->len, sizeof(desc->len));
549 address_space_cache_invalidate(cache, off_len, sizeof(desc->len));
550 }
551
552 static void vring_packed_desc_write_flags(VirtIODevice *vdev,
553 VRingPackedDesc *desc,
554 MemoryRegionCache *cache,
555 int i)
556 {
557 hwaddr off = i * sizeof(VRingPackedDesc) + offsetof(VRingPackedDesc, flags);
558
559 virtio_stw_phys_cached(vdev, cache, off, desc->flags);
560 address_space_cache_invalidate(cache, off, sizeof(desc->flags));
561 }
562
563 static void vring_packed_desc_write(VirtIODevice *vdev,
564 VRingPackedDesc *desc,
565 MemoryRegionCache *cache,
566 int i, bool strict_order)
567 {
568 vring_packed_desc_write_data(vdev, desc, cache, i);
569 if (strict_order) {
570 /* Make sure data is wrote before flags. */
571 smp_wmb();
572 }
573 vring_packed_desc_write_flags(vdev, desc, cache, i);
574 }
575
576 static inline bool is_desc_avail(uint16_t flags, bool wrap_counter)
577 {
578 bool avail, used;
579
580 avail = !!(flags & (1 << VRING_PACKED_DESC_F_AVAIL));
581 used = !!(flags & (1 << VRING_PACKED_DESC_F_USED));
582 return (avail != used) && (avail == wrap_counter);
583 }
584
585 /* Fetch avail_idx from VQ memory only when we really need to know if
586 * guest has added some buffers.
587 * Called within rcu_read_lock(). */
588 static int virtio_queue_empty_rcu(VirtQueue *vq)
589 {
590 if (virtio_device_disabled(vq->vdev)) {
591 return 1;
592 }
593
594 if (unlikely(!vq->vring.avail)) {
595 return 1;
596 }
597
598 if (vq->shadow_avail_idx != vq->last_avail_idx) {
599 return 0;
600 }
601
602 return vring_avail_idx(vq) == vq->last_avail_idx;
603 }
604
605 static int virtio_queue_split_empty(VirtQueue *vq)
606 {
607 bool empty;
608
609 if (virtio_device_disabled(vq->vdev)) {
610 return 1;
611 }
612
613 if (unlikely(!vq->vring.avail)) {
614 return 1;
615 }
616
617 if (vq->shadow_avail_idx != vq->last_avail_idx) {
618 return 0;
619 }
620
621 RCU_READ_LOCK_GUARD();
622 empty = vring_avail_idx(vq) == vq->last_avail_idx;
623 return empty;
624 }
625
626 /* Called within rcu_read_lock(). */
627 static int virtio_queue_packed_empty_rcu(VirtQueue *vq)
628 {
629 struct VRingPackedDesc desc;
630 VRingMemoryRegionCaches *cache;
631
632 if (unlikely(!vq->vring.desc)) {
633 return 1;
634 }
635
636 cache = vring_get_region_caches(vq);
637 if (!cache) {
638 return 1;
639 }
640
641 vring_packed_desc_read_flags(vq->vdev, &desc.flags, &cache->desc,
642 vq->last_avail_idx);
643
644 return !is_desc_avail(desc.flags, vq->last_avail_wrap_counter);
645 }
646
647 static int virtio_queue_packed_empty(VirtQueue *vq)
648 {
649 RCU_READ_LOCK_GUARD();
650 return virtio_queue_packed_empty_rcu(vq);
651 }
652
653 int virtio_queue_empty(VirtQueue *vq)
654 {
655 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
656 return virtio_queue_packed_empty(vq);
657 } else {
658 return virtio_queue_split_empty(vq);
659 }
660 }
661
662 static void virtqueue_unmap_sg(VirtQueue *vq, const VirtQueueElement *elem,
663 unsigned int len)
664 {
665 AddressSpace *dma_as = vq->vdev->dma_as;
666 unsigned int offset;
667 int i;
668
669 offset = 0;
670 for (i = 0; i < elem->in_num; i++) {
671 size_t size = MIN(len - offset, elem->in_sg[i].iov_len);
672
673 dma_memory_unmap(dma_as, elem->in_sg[i].iov_base,
674 elem->in_sg[i].iov_len,
675 DMA_DIRECTION_FROM_DEVICE, size);
676
677 offset += size;
678 }
679
680 for (i = 0; i < elem->out_num; i++)
681 dma_memory_unmap(dma_as, elem->out_sg[i].iov_base,
682 elem->out_sg[i].iov_len,
683 DMA_DIRECTION_TO_DEVICE,
684 elem->out_sg[i].iov_len);
685 }
686
687 /* virtqueue_detach_element:
688 * @vq: The #VirtQueue
689 * @elem: The #VirtQueueElement
690 * @len: number of bytes written
691 *
692 * Detach the element from the virtqueue. This function is suitable for device
693 * reset or other situations where a #VirtQueueElement is simply freed and will
694 * not be pushed or discarded.
695 */
696 void virtqueue_detach_element(VirtQueue *vq, const VirtQueueElement *elem,
697 unsigned int len)
698 {
699 vq->inuse -= elem->ndescs;
700 virtqueue_unmap_sg(vq, elem, len);
701 }
702
703 static void virtqueue_split_rewind(VirtQueue *vq, unsigned int num)
704 {
705 vq->last_avail_idx -= num;
706 }
707
708 static void virtqueue_packed_rewind(VirtQueue *vq, unsigned int num)
709 {
710 if (vq->last_avail_idx < num) {
711 vq->last_avail_idx = vq->vring.num + vq->last_avail_idx - num;
712 vq->last_avail_wrap_counter ^= 1;
713 } else {
714 vq->last_avail_idx -= num;
715 }
716 }
717
718 /* virtqueue_unpop:
719 * @vq: The #VirtQueue
720 * @elem: The #VirtQueueElement
721 * @len: number of bytes written
722 *
723 * Pretend the most recent element wasn't popped from the virtqueue. The next
724 * call to virtqueue_pop() will refetch the element.
725 */
726 void virtqueue_unpop(VirtQueue *vq, const VirtQueueElement *elem,
727 unsigned int len)
728 {
729
730 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
731 virtqueue_packed_rewind(vq, 1);
732 } else {
733 virtqueue_split_rewind(vq, 1);
734 }
735
736 virtqueue_detach_element(vq, elem, len);
737 }
738
739 /* virtqueue_rewind:
740 * @vq: The #VirtQueue
741 * @num: Number of elements to push back
742 *
743 * Pretend that elements weren't popped from the virtqueue. The next
744 * virtqueue_pop() will refetch the oldest element.
745 *
746 * Use virtqueue_unpop() instead if you have a VirtQueueElement.
747 *
748 * Returns: true on success, false if @num is greater than the number of in use
749 * elements.
750 */
751 bool virtqueue_rewind(VirtQueue *vq, unsigned int num)
752 {
753 if (num > vq->inuse) {
754 return false;
755 }
756
757 vq->inuse -= num;
758 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
759 virtqueue_packed_rewind(vq, num);
760 } else {
761 virtqueue_split_rewind(vq, num);
762 }
763 return true;
764 }
765
766 static void virtqueue_split_fill(VirtQueue *vq, const VirtQueueElement *elem,
767 unsigned int len, unsigned int idx)
768 {
769 VRingUsedElem uelem;
770
771 if (unlikely(!vq->vring.used)) {
772 return;
773 }
774
775 idx = (idx + vq->used_idx) % vq->vring.num;
776
777 uelem.id = elem->index;
778 uelem.len = len;
779 vring_used_write(vq, &uelem, idx);
780 }
781
782 static void virtqueue_packed_fill(VirtQueue *vq, const VirtQueueElement *elem,
783 unsigned int len, unsigned int idx)
784 {
785 vq->used_elems[idx].index = elem->index;
786 vq->used_elems[idx].len = len;
787 vq->used_elems[idx].ndescs = elem->ndescs;
788 }
789
790 static void virtqueue_packed_fill_desc(VirtQueue *vq,
791 const VirtQueueElement *elem,
792 unsigned int idx,
793 bool strict_order)
794 {
795 uint16_t head;
796 VRingMemoryRegionCaches *caches;
797 VRingPackedDesc desc = {
798 .id = elem->index,
799 .len = elem->len,
800 };
801 bool wrap_counter = vq->used_wrap_counter;
802
803 if (unlikely(!vq->vring.desc)) {
804 return;
805 }
806
807 head = vq->used_idx + idx;
808 if (head >= vq->vring.num) {
809 head -= vq->vring.num;
810 wrap_counter ^= 1;
811 }
812 if (wrap_counter) {
813 desc.flags |= (1 << VRING_PACKED_DESC_F_AVAIL);
814 desc.flags |= (1 << VRING_PACKED_DESC_F_USED);
815 } else {
816 desc.flags &= ~(1 << VRING_PACKED_DESC_F_AVAIL);
817 desc.flags &= ~(1 << VRING_PACKED_DESC_F_USED);
818 }
819
820 caches = vring_get_region_caches(vq);
821 if (!caches) {
822 return;
823 }
824
825 vring_packed_desc_write(vq->vdev, &desc, &caches->desc, head, strict_order);
826 }
827
828 /* Called within rcu_read_lock(). */
829 void virtqueue_fill(VirtQueue *vq, const VirtQueueElement *elem,
830 unsigned int len, unsigned int idx)
831 {
832 trace_virtqueue_fill(vq, elem, len, idx);
833
834 virtqueue_unmap_sg(vq, elem, len);
835
836 if (virtio_device_disabled(vq->vdev)) {
837 return;
838 }
839
840 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
841 virtqueue_packed_fill(vq, elem, len, idx);
842 } else {
843 virtqueue_split_fill(vq, elem, len, idx);
844 }
845 }
846
847 /* Called within rcu_read_lock(). */
848 static void virtqueue_split_flush(VirtQueue *vq, unsigned int count)
849 {
850 uint16_t old, new;
851
852 if (unlikely(!vq->vring.used)) {
853 return;
854 }
855
856 /* Make sure buffer is written before we update index. */
857 smp_wmb();
858 trace_virtqueue_flush(vq, count);
859 old = vq->used_idx;
860 new = old + count;
861 vring_used_idx_set(vq, new);
862 vq->inuse -= count;
863 if (unlikely((int16_t)(new - vq->signalled_used) < (uint16_t)(new - old)))
864 vq->signalled_used_valid = false;
865 }
866
867 static void virtqueue_packed_flush(VirtQueue *vq, unsigned int count)
868 {
869 unsigned int i, ndescs = 0;
870
871 if (unlikely(!vq->vring.desc)) {
872 return;
873 }
874
875 for (i = 1; i < count; i++) {
876 virtqueue_packed_fill_desc(vq, &vq->used_elems[i], i, false);
877 ndescs += vq->used_elems[i].ndescs;
878 }
879 virtqueue_packed_fill_desc(vq, &vq->used_elems[0], 0, true);
880 ndescs += vq->used_elems[0].ndescs;
881
882 vq->inuse -= ndescs;
883 vq->used_idx += ndescs;
884 if (vq->used_idx >= vq->vring.num) {
885 vq->used_idx -= vq->vring.num;
886 vq->used_wrap_counter ^= 1;
887 vq->signalled_used_valid = false;
888 }
889 }
890
891 void virtqueue_flush(VirtQueue *vq, unsigned int count)
892 {
893 if (virtio_device_disabled(vq->vdev)) {
894 vq->inuse -= count;
895 return;
896 }
897
898 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
899 virtqueue_packed_flush(vq, count);
900 } else {
901 virtqueue_split_flush(vq, count);
902 }
903 }
904
905 void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
906 unsigned int len)
907 {
908 RCU_READ_LOCK_GUARD();
909 virtqueue_fill(vq, elem, len, 0);
910 virtqueue_flush(vq, 1);
911 }
912
913 /* Called within rcu_read_lock(). */
914 static int virtqueue_num_heads(VirtQueue *vq, unsigned int idx)
915 {
916 uint16_t num_heads = vring_avail_idx(vq) - idx;
917
918 /* Check it isn't doing very strange things with descriptor numbers. */
919 if (num_heads > vq->vring.num) {
920 virtio_error(vq->vdev, "Guest moved used index from %u to %u",
921 idx, vq->shadow_avail_idx);
922 return -EINVAL;
923 }
924 /* On success, callers read a descriptor at vq->last_avail_idx.
925 * Make sure descriptor read does not bypass avail index read. */
926 if (num_heads) {
927 smp_rmb();
928 }
929
930 return num_heads;
931 }
932
933 /* Called within rcu_read_lock(). */
934 static bool virtqueue_get_head(VirtQueue *vq, unsigned int idx,
935 unsigned int *head)
936 {
937 /* Grab the next descriptor number they're advertising, and increment
938 * the index we've seen. */
939 *head = vring_avail_ring(vq, idx % vq->vring.num);
940
941 /* If their number is silly, that's a fatal mistake. */
942 if (*head >= vq->vring.num) {
943 virtio_error(vq->vdev, "Guest says index %u is available", *head);
944 return false;
945 }
946
947 return true;
948 }
949
950 enum {
951 VIRTQUEUE_READ_DESC_ERROR = -1,
952 VIRTQUEUE_READ_DESC_DONE = 0, /* end of chain */
953 VIRTQUEUE_READ_DESC_MORE = 1, /* more buffers in chain */
954 };
955
956 static int virtqueue_split_read_next_desc(VirtIODevice *vdev, VRingDesc *desc,
957 MemoryRegionCache *desc_cache,
958 unsigned int max, unsigned int *next)
959 {
960 /* If this descriptor says it doesn't chain, we're done. */
961 if (!(desc->flags & VRING_DESC_F_NEXT)) {
962 return VIRTQUEUE_READ_DESC_DONE;
963 }
964
965 /* Check they're not leading us off end of descriptors. */
966 *next = desc->next;
967 /* Make sure compiler knows to grab that: we don't want it changing! */
968 smp_wmb();
969
970 if (*next >= max) {
971 virtio_error(vdev, "Desc next is %u", *next);
972 return VIRTQUEUE_READ_DESC_ERROR;
973 }
974
975 vring_split_desc_read(vdev, desc, desc_cache, *next);
976 return VIRTQUEUE_READ_DESC_MORE;
977 }
978
979 /* Called within rcu_read_lock(). */
980 static void virtqueue_split_get_avail_bytes(VirtQueue *vq,
981 unsigned int *in_bytes, unsigned int *out_bytes,
982 unsigned max_in_bytes, unsigned max_out_bytes,
983 VRingMemoryRegionCaches *caches)
984 {
985 VirtIODevice *vdev = vq->vdev;
986 unsigned int max, idx;
987 unsigned int total_bufs, in_total, out_total;
988 MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
989 int64_t len = 0;
990 int rc;
991
992 idx = vq->last_avail_idx;
993 total_bufs = in_total = out_total = 0;
994
995 max = vq->vring.num;
996
997 while ((rc = virtqueue_num_heads(vq, idx)) > 0) {
998 MemoryRegionCache *desc_cache = &caches->desc;
999 unsigned int num_bufs;
1000 VRingDesc desc;
1001 unsigned int i;
1002
1003 num_bufs = total_bufs;
1004
1005 if (!virtqueue_get_head(vq, idx++, &i)) {
1006 goto err;
1007 }
1008
1009 vring_split_desc_read(vdev, &desc, desc_cache, i);
1010
1011 if (desc.flags & VRING_DESC_F_INDIRECT) {
1012 if (!desc.len || (desc.len % sizeof(VRingDesc))) {
1013 virtio_error(vdev, "Invalid size for indirect buffer table");
1014 goto err;
1015 }
1016
1017 /* If we've got too many, that implies a descriptor loop. */
1018 if (num_bufs >= max) {
1019 virtio_error(vdev, "Looped descriptor");
1020 goto err;
1021 }
1022
1023 /* loop over the indirect descriptor table */
1024 len = address_space_cache_init(&indirect_desc_cache,
1025 vdev->dma_as,
1026 desc.addr, desc.len, false);
1027 desc_cache = &indirect_desc_cache;
1028 if (len < desc.len) {
1029 virtio_error(vdev, "Cannot map indirect buffer");
1030 goto err;
1031 }
1032
1033 max = desc.len / sizeof(VRingDesc);
1034 num_bufs = i = 0;
1035 vring_split_desc_read(vdev, &desc, desc_cache, i);
1036 }
1037
1038 do {
1039 /* If we've got too many, that implies a descriptor loop. */
1040 if (++num_bufs > max) {
1041 virtio_error(vdev, "Looped descriptor");
1042 goto err;
1043 }
1044
1045 if (desc.flags & VRING_DESC_F_WRITE) {
1046 in_total += desc.len;
1047 } else {
1048 out_total += desc.len;
1049 }
1050 if (in_total >= max_in_bytes && out_total >= max_out_bytes) {
1051 goto done;
1052 }
1053
1054 rc = virtqueue_split_read_next_desc(vdev, &desc, desc_cache, max, &i);
1055 } while (rc == VIRTQUEUE_READ_DESC_MORE);
1056
1057 if (rc == VIRTQUEUE_READ_DESC_ERROR) {
1058 goto err;
1059 }
1060
1061 if (desc_cache == &indirect_desc_cache) {
1062 address_space_cache_destroy(&indirect_desc_cache);
1063 total_bufs++;
1064 } else {
1065 total_bufs = num_bufs;
1066 }
1067 }
1068
1069 if (rc < 0) {
1070 goto err;
1071 }
1072
1073 done:
1074 address_space_cache_destroy(&indirect_desc_cache);
1075 if (in_bytes) {
1076 *in_bytes = in_total;
1077 }
1078 if (out_bytes) {
1079 *out_bytes = out_total;
1080 }
1081 return;
1082
1083 err:
1084 in_total = out_total = 0;
1085 goto done;
1086 }
1087
1088 static int virtqueue_packed_read_next_desc(VirtQueue *vq,
1089 VRingPackedDesc *desc,
1090 MemoryRegionCache
1091 *desc_cache,
1092 unsigned int max,
1093 unsigned int *next,
1094 bool indirect)
1095 {
1096 /* If this descriptor says it doesn't chain, we're done. */
1097 if (!indirect && !(desc->flags & VRING_DESC_F_NEXT)) {
1098 return VIRTQUEUE_READ_DESC_DONE;
1099 }
1100
1101 ++*next;
1102 if (*next == max) {
1103 if (indirect) {
1104 return VIRTQUEUE_READ_DESC_DONE;
1105 } else {
1106 (*next) -= vq->vring.num;
1107 }
1108 }
1109
1110 vring_packed_desc_read(vq->vdev, desc, desc_cache, *next, false);
1111 return VIRTQUEUE_READ_DESC_MORE;
1112 }
1113
1114 /* Called within rcu_read_lock(). */
1115 static void virtqueue_packed_get_avail_bytes(VirtQueue *vq,
1116 unsigned int *in_bytes,
1117 unsigned int *out_bytes,
1118 unsigned max_in_bytes,
1119 unsigned max_out_bytes,
1120 VRingMemoryRegionCaches *caches)
1121 {
1122 VirtIODevice *vdev = vq->vdev;
1123 unsigned int max, idx;
1124 unsigned int total_bufs, in_total, out_total;
1125 MemoryRegionCache *desc_cache;
1126 MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
1127 int64_t len = 0;
1128 VRingPackedDesc desc;
1129 bool wrap_counter;
1130
1131 idx = vq->last_avail_idx;
1132 wrap_counter = vq->last_avail_wrap_counter;
1133 total_bufs = in_total = out_total = 0;
1134
1135 max = vq->vring.num;
1136
1137 for (;;) {
1138 unsigned int num_bufs = total_bufs;
1139 unsigned int i = idx;
1140 int rc;
1141
1142 desc_cache = &caches->desc;
1143 vring_packed_desc_read(vdev, &desc, desc_cache, idx, true);
1144 if (!is_desc_avail(desc.flags, wrap_counter)) {
1145 break;
1146 }
1147
1148 if (desc.flags & VRING_DESC_F_INDIRECT) {
1149 if (desc.len % sizeof(VRingPackedDesc)) {
1150 virtio_error(vdev, "Invalid size for indirect buffer table");
1151 goto err;
1152 }
1153
1154 /* If we've got too many, that implies a descriptor loop. */
1155 if (num_bufs >= max) {
1156 virtio_error(vdev, "Looped descriptor");
1157 goto err;
1158 }
1159
1160 /* loop over the indirect descriptor table */
1161 len = address_space_cache_init(&indirect_desc_cache,
1162 vdev->dma_as,
1163 desc.addr, desc.len, false);
1164 desc_cache = &indirect_desc_cache;
1165 if (len < desc.len) {
1166 virtio_error(vdev, "Cannot map indirect buffer");
1167 goto err;
1168 }
1169
1170 max = desc.len / sizeof(VRingPackedDesc);
1171 num_bufs = i = 0;
1172 vring_packed_desc_read(vdev, &desc, desc_cache, i, false);
1173 }
1174
1175 do {
1176 /* If we've got too many, that implies a descriptor loop. */
1177 if (++num_bufs > max) {
1178 virtio_error(vdev, "Looped descriptor");
1179 goto err;
1180 }
1181
1182 if (desc.flags & VRING_DESC_F_WRITE) {
1183 in_total += desc.len;
1184 } else {
1185 out_total += desc.len;
1186 }
1187 if (in_total >= max_in_bytes && out_total >= max_out_bytes) {
1188 goto done;
1189 }
1190
1191 rc = virtqueue_packed_read_next_desc(vq, &desc, desc_cache, max,
1192 &i, desc_cache ==
1193 &indirect_desc_cache);
1194 } while (rc == VIRTQUEUE_READ_DESC_MORE);
1195
1196 if (desc_cache == &indirect_desc_cache) {
1197 address_space_cache_destroy(&indirect_desc_cache);
1198 total_bufs++;
1199 idx++;
1200 } else {
1201 idx += num_bufs - total_bufs;
1202 total_bufs = num_bufs;
1203 }
1204
1205 if (idx >= vq->vring.num) {
1206 idx -= vq->vring.num;
1207 wrap_counter ^= 1;
1208 }
1209 }
1210
1211 /* Record the index and wrap counter for a kick we want */
1212 vq->shadow_avail_idx = idx;
1213 vq->shadow_avail_wrap_counter = wrap_counter;
1214 done:
1215 address_space_cache_destroy(&indirect_desc_cache);
1216 if (in_bytes) {
1217 *in_bytes = in_total;
1218 }
1219 if (out_bytes) {
1220 *out_bytes = out_total;
1221 }
1222 return;
1223
1224 err:
1225 in_total = out_total = 0;
1226 goto done;
1227 }
1228
1229 void virtqueue_get_avail_bytes(VirtQueue *vq, unsigned int *in_bytes,
1230 unsigned int *out_bytes,
1231 unsigned max_in_bytes, unsigned max_out_bytes)
1232 {
1233 uint16_t desc_size;
1234 VRingMemoryRegionCaches *caches;
1235
1236 RCU_READ_LOCK_GUARD();
1237
1238 if (unlikely(!vq->vring.desc)) {
1239 goto err;
1240 }
1241
1242 caches = vring_get_region_caches(vq);
1243 if (!caches) {
1244 goto err;
1245 }
1246
1247 desc_size = virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED) ?
1248 sizeof(VRingPackedDesc) : sizeof(VRingDesc);
1249 if (caches->desc.len < vq->vring.num * desc_size) {
1250 virtio_error(vq->vdev, "Cannot map descriptor ring");
1251 goto err;
1252 }
1253
1254 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
1255 virtqueue_packed_get_avail_bytes(vq, in_bytes, out_bytes,
1256 max_in_bytes, max_out_bytes,
1257 caches);
1258 } else {
1259 virtqueue_split_get_avail_bytes(vq, in_bytes, out_bytes,
1260 max_in_bytes, max_out_bytes,
1261 caches);
1262 }
1263
1264 return;
1265 err:
1266 if (in_bytes) {
1267 *in_bytes = 0;
1268 }
1269 if (out_bytes) {
1270 *out_bytes = 0;
1271 }
1272 }
1273
1274 int virtqueue_avail_bytes(VirtQueue *vq, unsigned int in_bytes,
1275 unsigned int out_bytes)
1276 {
1277 unsigned int in_total, out_total;
1278
1279 virtqueue_get_avail_bytes(vq, &in_total, &out_total, in_bytes, out_bytes);
1280 return in_bytes <= in_total && out_bytes <= out_total;
1281 }
1282
1283 static bool virtqueue_map_desc(VirtIODevice *vdev, unsigned int *p_num_sg,
1284 hwaddr *addr, struct iovec *iov,
1285 unsigned int max_num_sg, bool is_write,
1286 hwaddr pa, size_t sz)
1287 {
1288 bool ok = false;
1289 unsigned num_sg = *p_num_sg;
1290 assert(num_sg <= max_num_sg);
1291
1292 if (!sz) {
1293 virtio_error(vdev, "virtio: zero sized buffers are not allowed");
1294 goto out;
1295 }
1296
1297 while (sz) {
1298 hwaddr len = sz;
1299
1300 if (num_sg == max_num_sg) {
1301 virtio_error(vdev, "virtio: too many write descriptors in "
1302 "indirect table");
1303 goto out;
1304 }
1305
1306 iov[num_sg].iov_base = dma_memory_map(vdev->dma_as, pa, &len,
1307 is_write ?
1308 DMA_DIRECTION_FROM_DEVICE :
1309 DMA_DIRECTION_TO_DEVICE,
1310 MEMTXATTRS_UNSPECIFIED);
1311 if (!iov[num_sg].iov_base) {
1312 virtio_error(vdev, "virtio: bogus descriptor or out of resources");
1313 goto out;
1314 }
1315
1316 iov[num_sg].iov_len = len;
1317 addr[num_sg] = pa;
1318
1319 sz -= len;
1320 pa += len;
1321 num_sg++;
1322 }
1323 ok = true;
1324
1325 out:
1326 *p_num_sg = num_sg;
1327 return ok;
1328 }
1329
1330 /* Only used by error code paths before we have a VirtQueueElement (therefore
1331 * virtqueue_unmap_sg() can't be used). Assumes buffers weren't written to
1332 * yet.
1333 */
1334 static void virtqueue_undo_map_desc(unsigned int out_num, unsigned int in_num,
1335 struct iovec *iov)
1336 {
1337 unsigned int i;
1338
1339 for (i = 0; i < out_num + in_num; i++) {
1340 int is_write = i >= out_num;
1341
1342 cpu_physical_memory_unmap(iov->iov_base, iov->iov_len, is_write, 0);
1343 iov++;
1344 }
1345 }
1346
1347 static void virtqueue_map_iovec(VirtIODevice *vdev, struct iovec *sg,
1348 hwaddr *addr, unsigned int num_sg,
1349 bool is_write)
1350 {
1351 unsigned int i;
1352 hwaddr len;
1353
1354 for (i = 0; i < num_sg; i++) {
1355 len = sg[i].iov_len;
1356 sg[i].iov_base = dma_memory_map(vdev->dma_as,
1357 addr[i], &len, is_write ?
1358 DMA_DIRECTION_FROM_DEVICE :
1359 DMA_DIRECTION_TO_DEVICE,
1360 MEMTXATTRS_UNSPECIFIED);
1361 if (!sg[i].iov_base) {
1362 error_report("virtio: error trying to map MMIO memory");
1363 exit(1);
1364 }
1365 if (len != sg[i].iov_len) {
1366 error_report("virtio: unexpected memory split");
1367 exit(1);
1368 }
1369 }
1370 }
1371
1372 void virtqueue_map(VirtIODevice *vdev, VirtQueueElement *elem)
1373 {
1374 virtqueue_map_iovec(vdev, elem->in_sg, elem->in_addr, elem->in_num, true);
1375 virtqueue_map_iovec(vdev, elem->out_sg, elem->out_addr, elem->out_num,
1376 false);
1377 }
1378
1379 static void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned in_num)
1380 {
1381 VirtQueueElement *elem;
1382 size_t in_addr_ofs = QEMU_ALIGN_UP(sz, __alignof__(elem->in_addr[0]));
1383 size_t out_addr_ofs = in_addr_ofs + in_num * sizeof(elem->in_addr[0]);
1384 size_t out_addr_end = out_addr_ofs + out_num * sizeof(elem->out_addr[0]);
1385 size_t in_sg_ofs = QEMU_ALIGN_UP(out_addr_end, __alignof__(elem->in_sg[0]));
1386 size_t out_sg_ofs = in_sg_ofs + in_num * sizeof(elem->in_sg[0]);
1387 size_t out_sg_end = out_sg_ofs + out_num * sizeof(elem->out_sg[0]);
1388
1389 assert(sz >= sizeof(VirtQueueElement));
1390 elem = g_malloc(out_sg_end);
1391 trace_virtqueue_alloc_element(elem, sz, in_num, out_num);
1392 elem->out_num = out_num;
1393 elem->in_num = in_num;
1394 elem->in_addr = (void *)elem + in_addr_ofs;
1395 elem->out_addr = (void *)elem + out_addr_ofs;
1396 elem->in_sg = (void *)elem + in_sg_ofs;
1397 elem->out_sg = (void *)elem + out_sg_ofs;
1398 return elem;
1399 }
1400
1401 static void *virtqueue_split_pop(VirtQueue *vq, size_t sz)
1402 {
1403 unsigned int i, head, max;
1404 VRingMemoryRegionCaches *caches;
1405 MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
1406 MemoryRegionCache *desc_cache;
1407 int64_t len;
1408 VirtIODevice *vdev = vq->vdev;
1409 VirtQueueElement *elem = NULL;
1410 unsigned out_num, in_num, elem_entries;
1411 hwaddr addr[VIRTQUEUE_MAX_SIZE];
1412 struct iovec iov[VIRTQUEUE_MAX_SIZE];
1413 VRingDesc desc;
1414 int rc;
1415
1416 RCU_READ_LOCK_GUARD();
1417 if (virtio_queue_empty_rcu(vq)) {
1418 goto done;
1419 }
1420 /* Needed after virtio_queue_empty(), see comment in
1421 * virtqueue_num_heads(). */
1422 smp_rmb();
1423
1424 /* When we start there are none of either input nor output. */
1425 out_num = in_num = elem_entries = 0;
1426
1427 max = vq->vring.num;
1428
1429 if (vq->inuse >= vq->vring.num) {
1430 virtio_error(vdev, "Virtqueue size exceeded");
1431 goto done;
1432 }
1433
1434 if (!virtqueue_get_head(vq, vq->last_avail_idx++, &head)) {
1435 goto done;
1436 }
1437
1438 if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
1439 vring_set_avail_event(vq, vq->last_avail_idx);
1440 }
1441
1442 i = head;
1443
1444 caches = vring_get_region_caches(vq);
1445 if (!caches) {
1446 virtio_error(vdev, "Region caches not initialized");
1447 goto done;
1448 }
1449
1450 if (caches->desc.len < max * sizeof(VRingDesc)) {
1451 virtio_error(vdev, "Cannot map descriptor ring");
1452 goto done;
1453 }
1454
1455 desc_cache = &caches->desc;
1456 vring_split_desc_read(vdev, &desc, desc_cache, i);
1457 if (desc.flags & VRING_DESC_F_INDIRECT) {
1458 if (!desc.len || (desc.len % sizeof(VRingDesc))) {
1459 virtio_error(vdev, "Invalid size for indirect buffer table");
1460 goto done;
1461 }
1462
1463 /* loop over the indirect descriptor table */
1464 len = address_space_cache_init(&indirect_desc_cache, vdev->dma_as,
1465 desc.addr, desc.len, false);
1466 desc_cache = &indirect_desc_cache;
1467 if (len < desc.len) {
1468 virtio_error(vdev, "Cannot map indirect buffer");
1469 goto done;
1470 }
1471
1472 max = desc.len / sizeof(VRingDesc);
1473 i = 0;
1474 vring_split_desc_read(vdev, &desc, desc_cache, i);
1475 }
1476
1477 /* Collect all the descriptors */
1478 do {
1479 bool map_ok;
1480
1481 if (desc.flags & VRING_DESC_F_WRITE) {
1482 map_ok = virtqueue_map_desc(vdev, &in_num, addr + out_num,
1483 iov + out_num,
1484 VIRTQUEUE_MAX_SIZE - out_num, true,
1485 desc.addr, desc.len);
1486 } else {
1487 if (in_num) {
1488 virtio_error(vdev, "Incorrect order for descriptors");
1489 goto err_undo_map;
1490 }
1491 map_ok = virtqueue_map_desc(vdev, &out_num, addr, iov,
1492 VIRTQUEUE_MAX_SIZE, false,
1493 desc.addr, desc.len);
1494 }
1495 if (!map_ok) {
1496 goto err_undo_map;
1497 }
1498
1499 /* If we've got too many, that implies a descriptor loop. */
1500 if (++elem_entries > max) {
1501 virtio_error(vdev, "Looped descriptor");
1502 goto err_undo_map;
1503 }
1504
1505 rc = virtqueue_split_read_next_desc(vdev, &desc, desc_cache, max, &i);
1506 } while (rc == VIRTQUEUE_READ_DESC_MORE);
1507
1508 if (rc == VIRTQUEUE_READ_DESC_ERROR) {
1509 goto err_undo_map;
1510 }
1511
1512 /* Now copy what we have collected and mapped */
1513 elem = virtqueue_alloc_element(sz, out_num, in_num);
1514 elem->index = head;
1515 elem->ndescs = 1;
1516 for (i = 0; i < out_num; i++) {
1517 elem->out_addr[i] = addr[i];
1518 elem->out_sg[i] = iov[i];
1519 }
1520 for (i = 0; i < in_num; i++) {
1521 elem->in_addr[i] = addr[out_num + i];
1522 elem->in_sg[i] = iov[out_num + i];
1523 }
1524
1525 vq->inuse++;
1526
1527 trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num);
1528 done:
1529 address_space_cache_destroy(&indirect_desc_cache);
1530
1531 return elem;
1532
1533 err_undo_map:
1534 virtqueue_undo_map_desc(out_num, in_num, iov);
1535 goto done;
1536 }
1537
1538 static void *virtqueue_packed_pop(VirtQueue *vq, size_t sz)
1539 {
1540 unsigned int i, max;
1541 VRingMemoryRegionCaches *caches;
1542 MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
1543 MemoryRegionCache *desc_cache;
1544 int64_t len;
1545 VirtIODevice *vdev = vq->vdev;
1546 VirtQueueElement *elem = NULL;
1547 unsigned out_num, in_num, elem_entries;
1548 hwaddr addr[VIRTQUEUE_MAX_SIZE];
1549 struct iovec iov[VIRTQUEUE_MAX_SIZE];
1550 VRingPackedDesc desc;
1551 uint16_t id;
1552 int rc;
1553
1554 RCU_READ_LOCK_GUARD();
1555 if (virtio_queue_packed_empty_rcu(vq)) {
1556 goto done;
1557 }
1558
1559 /* When we start there are none of either input nor output. */
1560 out_num = in_num = elem_entries = 0;
1561
1562 max = vq->vring.num;
1563
1564 if (vq->inuse >= vq->vring.num) {
1565 virtio_error(vdev, "Virtqueue size exceeded");
1566 goto done;
1567 }
1568
1569 i = vq->last_avail_idx;
1570
1571 caches = vring_get_region_caches(vq);
1572 if (!caches) {
1573 virtio_error(vdev, "Region caches not initialized");
1574 goto done;
1575 }
1576
1577 if (caches->desc.len < max * sizeof(VRingDesc)) {
1578 virtio_error(vdev, "Cannot map descriptor ring");
1579 goto done;
1580 }
1581
1582 desc_cache = &caches->desc;
1583 vring_packed_desc_read(vdev, &desc, desc_cache, i, true);
1584 id = desc.id;
1585 if (desc.flags & VRING_DESC_F_INDIRECT) {
1586 if (desc.len % sizeof(VRingPackedDesc)) {
1587 virtio_error(vdev, "Invalid size for indirect buffer table");
1588 goto done;
1589 }
1590
1591 /* loop over the indirect descriptor table */
1592 len = address_space_cache_init(&indirect_desc_cache, vdev->dma_as,
1593 desc.addr, desc.len, false);
1594 desc_cache = &indirect_desc_cache;
1595 if (len < desc.len) {
1596 virtio_error(vdev, "Cannot map indirect buffer");
1597 goto done;
1598 }
1599
1600 max = desc.len / sizeof(VRingPackedDesc);
1601 i = 0;
1602 vring_packed_desc_read(vdev, &desc, desc_cache, i, false);
1603 }
1604
1605 /* Collect all the descriptors */
1606 do {
1607 bool map_ok;
1608
1609 if (desc.flags & VRING_DESC_F_WRITE) {
1610 map_ok = virtqueue_map_desc(vdev, &in_num, addr + out_num,
1611 iov + out_num,
1612 VIRTQUEUE_MAX_SIZE - out_num, true,
1613 desc.addr, desc.len);
1614 } else {
1615 if (in_num) {
1616 virtio_error(vdev, "Incorrect order for descriptors");
1617 goto err_undo_map;
1618 }
1619 map_ok = virtqueue_map_desc(vdev, &out_num, addr, iov,
1620 VIRTQUEUE_MAX_SIZE, false,
1621 desc.addr, desc.len);
1622 }
1623 if (!map_ok) {
1624 goto err_undo_map;
1625 }
1626
1627 /* If we've got too many, that implies a descriptor loop. */
1628 if (++elem_entries > max) {
1629 virtio_error(vdev, "Looped descriptor");
1630 goto err_undo_map;
1631 }
1632
1633 rc = virtqueue_packed_read_next_desc(vq, &desc, desc_cache, max, &i,
1634 desc_cache ==
1635 &indirect_desc_cache);
1636 } while (rc == VIRTQUEUE_READ_DESC_MORE);
1637
1638 /* Now copy what we have collected and mapped */
1639 elem = virtqueue_alloc_element(sz, out_num, in_num);
1640 for (i = 0; i < out_num; i++) {
1641 elem->out_addr[i] = addr[i];
1642 elem->out_sg[i] = iov[i];
1643 }
1644 for (i = 0; i < in_num; i++) {
1645 elem->in_addr[i] = addr[out_num + i];
1646 elem->in_sg[i] = iov[out_num + i];
1647 }
1648
1649 elem->index = id;
1650 elem->ndescs = (desc_cache == &indirect_desc_cache) ? 1 : elem_entries;
1651 vq->last_avail_idx += elem->ndescs;
1652 vq->inuse += elem->ndescs;
1653
1654 if (vq->last_avail_idx >= vq->vring.num) {
1655 vq->last_avail_idx -= vq->vring.num;
1656 vq->last_avail_wrap_counter ^= 1;
1657 }
1658
1659 vq->shadow_avail_idx = vq->last_avail_idx;
1660 vq->shadow_avail_wrap_counter = vq->last_avail_wrap_counter;
1661
1662 trace_virtqueue_pop(vq, elem, elem->in_num, elem->out_num);
1663 done:
1664 address_space_cache_destroy(&indirect_desc_cache);
1665
1666 return elem;
1667
1668 err_undo_map:
1669 virtqueue_undo_map_desc(out_num, in_num, iov);
1670 goto done;
1671 }
1672
1673 void *virtqueue_pop(VirtQueue *vq, size_t sz)
1674 {
1675 if (virtio_device_disabled(vq->vdev)) {
1676 return NULL;
1677 }
1678
1679 if (virtio_vdev_has_feature(vq->vdev, VIRTIO_F_RING_PACKED)) {
1680 return virtqueue_packed_pop(vq, sz);
1681 } else {
1682 return virtqueue_split_pop(vq, sz);
1683 }
1684 }
1685
1686 static unsigned int virtqueue_packed_drop_all(VirtQueue *vq)
1687 {
1688 VRingMemoryRegionCaches *caches;
1689 MemoryRegionCache *desc_cache;
1690 unsigned int dropped = 0;
1691 VirtQueueElement elem = {};
1692 VirtIODevice *vdev = vq->vdev;
1693 VRingPackedDesc desc;
1694
1695 RCU_READ_LOCK_GUARD();
1696
1697 caches = vring_get_region_caches(vq);
1698 if (!caches) {
1699 return 0;
1700 }
1701
1702 desc_cache = &caches->desc;
1703
1704 virtio_queue_set_notification(vq, 0);
1705
1706 while (vq->inuse < vq->vring.num) {
1707 unsigned int idx = vq->last_avail_idx;
1708 /*
1709 * works similar to virtqueue_pop but does not map buffers
1710 * and does not allocate any memory.
1711 */
1712 vring_packed_desc_read(vdev, &desc, desc_cache,
1713 vq->last_avail_idx , true);
1714 if (!is_desc_avail(desc.flags, vq->last_avail_wrap_counter)) {
1715 break;
1716 }
1717 elem.index = desc.id;
1718 elem.ndescs = 1;
1719 while (virtqueue_packed_read_next_desc(vq, &desc, desc_cache,
1720 vq->vring.num, &idx, false)) {
1721 ++elem.ndescs;
1722 }
1723 /*
1724 * immediately push the element, nothing to unmap
1725 * as both in_num and out_num are set to 0.
1726 */
1727 virtqueue_push(vq, &elem, 0);
1728 dropped++;
1729 vq->last_avail_idx += elem.ndescs;
1730 if (vq->last_avail_idx >= vq->vring.num) {
1731 vq->last_avail_idx -= vq->vring.num;
1732 vq->last_avail_wrap_counter ^= 1;
1733 }
1734 }
1735
1736 return dropped;
1737 }
1738
1739 static unsigned int virtqueue_split_drop_all(VirtQueue *vq)
1740 {
1741 unsigned int dropped = 0;
1742 VirtQueueElement elem = {};
1743 VirtIODevice *vdev = vq->vdev;
1744 bool fEventIdx = virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
1745
1746 while (!virtio_queue_empty(vq) && vq->inuse < vq->vring.num) {
1747 /* works similar to virtqueue_pop but does not map buffers
1748 * and does not allocate any memory */
1749 smp_rmb();
1750 if (!virtqueue_get_head(vq, vq->last_avail_idx, &elem.index)) {
1751 break;
1752 }
1753 vq->inuse++;
1754 vq->last_avail_idx++;
1755 if (fEventIdx) {
1756 vring_set_avail_event(vq, vq->last_avail_idx);
1757 }
1758 /* immediately push the element, nothing to unmap
1759 * as both in_num and out_num are set to 0 */
1760 virtqueue_push(vq, &elem, 0);
1761 dropped++;
1762 }
1763
1764 return dropped;
1765 }
1766
1767 /* virtqueue_drop_all:
1768 * @vq: The #VirtQueue
1769 * Drops all queued buffers and indicates them to the guest
1770 * as if they are done. Useful when buffers can not be
1771 * processed but must be returned to the guest.
1772 */
1773 unsigned int virtqueue_drop_all(VirtQueue *vq)
1774 {
1775 struct VirtIODevice *vdev = vq->vdev;
1776
1777 if (virtio_device_disabled(vq->vdev)) {
1778 return 0;
1779 }
1780
1781 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
1782 return virtqueue_packed_drop_all(vq);
1783 } else {
1784 return virtqueue_split_drop_all(vq);
1785 }
1786 }
1787
1788 /* Reading and writing a structure directly to QEMUFile is *awful*, but
1789 * it is what QEMU has always done by mistake. We can change it sooner
1790 * or later by bumping the version number of the affected vm states.
1791 * In the meanwhile, since the in-memory layout of VirtQueueElement
1792 * has changed, we need to marshal to and from the layout that was
1793 * used before the change.
1794 */
1795 typedef struct VirtQueueElementOld {
1796 unsigned int index;
1797 unsigned int out_num;
1798 unsigned int in_num;
1799 hwaddr in_addr[VIRTQUEUE_MAX_SIZE];
1800 hwaddr out_addr[VIRTQUEUE_MAX_SIZE];
1801 struct iovec in_sg[VIRTQUEUE_MAX_SIZE];
1802 struct iovec out_sg[VIRTQUEUE_MAX_SIZE];
1803 } VirtQueueElementOld;
1804
1805 void *qemu_get_virtqueue_element(VirtIODevice *vdev, QEMUFile *f, size_t sz)
1806 {
1807 VirtQueueElement *elem;
1808 VirtQueueElementOld data;
1809 int i;
1810
1811 qemu_get_buffer(f, (uint8_t *)&data, sizeof(VirtQueueElementOld));
1812
1813 /* TODO: teach all callers that this can fail, and return failure instead
1814 * of asserting here.
1815 * This is just one thing (there are probably more) that must be
1816 * fixed before we can allow NDEBUG compilation.
1817 */
1818 assert(ARRAY_SIZE(data.in_addr) >= data.in_num);
1819 assert(ARRAY_SIZE(data.out_addr) >= data.out_num);
1820
1821 elem = virtqueue_alloc_element(sz, data.out_num, data.in_num);
1822 elem->index = data.index;
1823
1824 for (i = 0; i < elem->in_num; i++) {
1825 elem->in_addr[i] = data.in_addr[i];
1826 }
1827
1828 for (i = 0; i < elem->out_num; i++) {
1829 elem->out_addr[i] = data.out_addr[i];
1830 }
1831
1832 for (i = 0; i < elem->in_num; i++) {
1833 /* Base is overwritten by virtqueue_map. */
1834 elem->in_sg[i].iov_base = 0;
1835 elem->in_sg[i].iov_len = data.in_sg[i].iov_len;
1836 }
1837
1838 for (i = 0; i < elem->out_num; i++) {
1839 /* Base is overwritten by virtqueue_map. */
1840 elem->out_sg[i].iov_base = 0;
1841 elem->out_sg[i].iov_len = data.out_sg[i].iov_len;
1842 }
1843
1844 if (virtio_host_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
1845 qemu_get_be32s(f, &elem->ndescs);
1846 }
1847
1848 virtqueue_map(vdev, elem);
1849 return elem;
1850 }
1851
1852 void qemu_put_virtqueue_element(VirtIODevice *vdev, QEMUFile *f,
1853 VirtQueueElement *elem)
1854 {
1855 VirtQueueElementOld data;
1856 int i;
1857
1858 memset(&data, 0, sizeof(data));
1859 data.index = elem->index;
1860 data.in_num = elem->in_num;
1861 data.out_num = elem->out_num;
1862
1863 for (i = 0; i < elem->in_num; i++) {
1864 data.in_addr[i] = elem->in_addr[i];
1865 }
1866
1867 for (i = 0; i < elem->out_num; i++) {
1868 data.out_addr[i] = elem->out_addr[i];
1869 }
1870
1871 for (i = 0; i < elem->in_num; i++) {
1872 /* Base is overwritten by virtqueue_map when loading. Do not
1873 * save it, as it would leak the QEMU address space layout. */
1874 data.in_sg[i].iov_len = elem->in_sg[i].iov_len;
1875 }
1876
1877 for (i = 0; i < elem->out_num; i++) {
1878 /* Do not save iov_base as above. */
1879 data.out_sg[i].iov_len = elem->out_sg[i].iov_len;
1880 }
1881
1882 if (virtio_host_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
1883 qemu_put_be32s(f, &elem->ndescs);
1884 }
1885
1886 qemu_put_buffer(f, (uint8_t *)&data, sizeof(VirtQueueElementOld));
1887 }
1888
1889 /* virtio device */
1890 static void virtio_notify_vector(VirtIODevice *vdev, uint16_t vector)
1891 {
1892 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
1893 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
1894
1895 if (virtio_device_disabled(vdev)) {
1896 return;
1897 }
1898
1899 if (k->notify) {
1900 k->notify(qbus->parent, vector);
1901 }
1902 }
1903
1904 void virtio_update_irq(VirtIODevice *vdev)
1905 {
1906 virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
1907 }
1908
1909 static int virtio_validate_features(VirtIODevice *vdev)
1910 {
1911 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1912
1913 if (virtio_host_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM) &&
1914 !virtio_vdev_has_feature(vdev, VIRTIO_F_IOMMU_PLATFORM)) {
1915 return -EFAULT;
1916 }
1917
1918 if (k->validate_features) {
1919 return k->validate_features(vdev);
1920 } else {
1921 return 0;
1922 }
1923 }
1924
1925 int virtio_set_status(VirtIODevice *vdev, uint8_t val)
1926 {
1927 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1928 trace_virtio_set_status(vdev, val);
1929
1930 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
1931 if (!(vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) &&
1932 val & VIRTIO_CONFIG_S_FEATURES_OK) {
1933 int ret = virtio_validate_features(vdev);
1934
1935 if (ret) {
1936 return ret;
1937 }
1938 }
1939 }
1940
1941 if ((vdev->status & VIRTIO_CONFIG_S_DRIVER_OK) !=
1942 (val & VIRTIO_CONFIG_S_DRIVER_OK)) {
1943 virtio_set_started(vdev, val & VIRTIO_CONFIG_S_DRIVER_OK);
1944 }
1945
1946 if (k->set_status) {
1947 k->set_status(vdev, val);
1948 }
1949 vdev->status = val;
1950
1951 return 0;
1952 }
1953
1954 static enum virtio_device_endian virtio_default_endian(void)
1955 {
1956 if (target_words_bigendian()) {
1957 return VIRTIO_DEVICE_ENDIAN_BIG;
1958 } else {
1959 return VIRTIO_DEVICE_ENDIAN_LITTLE;
1960 }
1961 }
1962
1963 static enum virtio_device_endian virtio_current_cpu_endian(void)
1964 {
1965 if (cpu_virtio_is_big_endian(current_cpu)) {
1966 return VIRTIO_DEVICE_ENDIAN_BIG;
1967 } else {
1968 return VIRTIO_DEVICE_ENDIAN_LITTLE;
1969 }
1970 }
1971
1972 void virtio_reset(void *opaque)
1973 {
1974 VirtIODevice *vdev = opaque;
1975 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
1976 int i;
1977
1978 virtio_set_status(vdev, 0);
1979 if (current_cpu) {
1980 /* Guest initiated reset */
1981 vdev->device_endian = virtio_current_cpu_endian();
1982 } else {
1983 /* System reset */
1984 vdev->device_endian = virtio_default_endian();
1985 }
1986
1987 if (k->reset) {
1988 k->reset(vdev);
1989 }
1990
1991 vdev->start_on_kick = false;
1992 vdev->started = false;
1993 vdev->broken = false;
1994 vdev->guest_features = 0;
1995 vdev->queue_sel = 0;
1996 vdev->status = 0;
1997 vdev->disabled = false;
1998 qatomic_set(&vdev->isr, 0);
1999 vdev->config_vector = VIRTIO_NO_VECTOR;
2000 virtio_notify_vector(vdev, vdev->config_vector);
2001
2002 for(i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2003 vdev->vq[i].vring.desc = 0;
2004 vdev->vq[i].vring.avail = 0;
2005 vdev->vq[i].vring.used = 0;
2006 vdev->vq[i].last_avail_idx = 0;
2007 vdev->vq[i].shadow_avail_idx = 0;
2008 vdev->vq[i].used_idx = 0;
2009 vdev->vq[i].last_avail_wrap_counter = true;
2010 vdev->vq[i].shadow_avail_wrap_counter = true;
2011 vdev->vq[i].used_wrap_counter = true;
2012 virtio_queue_set_vector(vdev, i, VIRTIO_NO_VECTOR);
2013 vdev->vq[i].signalled_used = 0;
2014 vdev->vq[i].signalled_used_valid = false;
2015 vdev->vq[i].notification = true;
2016 vdev->vq[i].vring.num = vdev->vq[i].vring.num_default;
2017 vdev->vq[i].inuse = 0;
2018 virtio_virtqueue_reset_region_cache(&vdev->vq[i]);
2019 }
2020 }
2021
2022 uint32_t virtio_config_readb(VirtIODevice *vdev, uint32_t addr)
2023 {
2024 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2025 uint8_t val;
2026
2027 if (addr + sizeof(val) > vdev->config_len) {
2028 return (uint32_t)-1;
2029 }
2030
2031 k->get_config(vdev, vdev->config);
2032
2033 val = ldub_p(vdev->config + addr);
2034 return val;
2035 }
2036
2037 uint32_t virtio_config_readw(VirtIODevice *vdev, uint32_t addr)
2038 {
2039 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2040 uint16_t val;
2041
2042 if (addr + sizeof(val) > vdev->config_len) {
2043 return (uint32_t)-1;
2044 }
2045
2046 k->get_config(vdev, vdev->config);
2047
2048 val = lduw_p(vdev->config + addr);
2049 return val;
2050 }
2051
2052 uint32_t virtio_config_readl(VirtIODevice *vdev, uint32_t addr)
2053 {
2054 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2055 uint32_t val;
2056
2057 if (addr + sizeof(val) > vdev->config_len) {
2058 return (uint32_t)-1;
2059 }
2060
2061 k->get_config(vdev, vdev->config);
2062
2063 val = ldl_p(vdev->config + addr);
2064 return val;
2065 }
2066
2067 void virtio_config_writeb(VirtIODevice *vdev, uint32_t addr, uint32_t data)
2068 {
2069 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2070 uint8_t val = data;
2071
2072 if (addr + sizeof(val) > vdev->config_len) {
2073 return;
2074 }
2075
2076 stb_p(vdev->config + addr, val);
2077
2078 if (k->set_config) {
2079 k->set_config(vdev, vdev->config);
2080 }
2081 }
2082
2083 void virtio_config_writew(VirtIODevice *vdev, uint32_t addr, uint32_t data)
2084 {
2085 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2086 uint16_t val = data;
2087
2088 if (addr + sizeof(val) > vdev->config_len) {
2089 return;
2090 }
2091
2092 stw_p(vdev->config + addr, val);
2093
2094 if (k->set_config) {
2095 k->set_config(vdev, vdev->config);
2096 }
2097 }
2098
2099 void virtio_config_writel(VirtIODevice *vdev, uint32_t addr, uint32_t data)
2100 {
2101 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2102 uint32_t val = data;
2103
2104 if (addr + sizeof(val) > vdev->config_len) {
2105 return;
2106 }
2107
2108 stl_p(vdev->config + addr, val);
2109
2110 if (k->set_config) {
2111 k->set_config(vdev, vdev->config);
2112 }
2113 }
2114
2115 uint32_t virtio_config_modern_readb(VirtIODevice *vdev, uint32_t addr)
2116 {
2117 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2118 uint8_t val;
2119
2120 if (addr + sizeof(val) > vdev->config_len) {
2121 return (uint32_t)-1;
2122 }
2123
2124 k->get_config(vdev, vdev->config);
2125
2126 val = ldub_p(vdev->config + addr);
2127 return val;
2128 }
2129
2130 uint32_t virtio_config_modern_readw(VirtIODevice *vdev, uint32_t addr)
2131 {
2132 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2133 uint16_t val;
2134
2135 if (addr + sizeof(val) > vdev->config_len) {
2136 return (uint32_t)-1;
2137 }
2138
2139 k->get_config(vdev, vdev->config);
2140
2141 val = lduw_le_p(vdev->config + addr);
2142 return val;
2143 }
2144
2145 uint32_t virtio_config_modern_readl(VirtIODevice *vdev, uint32_t addr)
2146 {
2147 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2148 uint32_t val;
2149
2150 if (addr + sizeof(val) > vdev->config_len) {
2151 return (uint32_t)-1;
2152 }
2153
2154 k->get_config(vdev, vdev->config);
2155
2156 val = ldl_le_p(vdev->config + addr);
2157 return val;
2158 }
2159
2160 void virtio_config_modern_writeb(VirtIODevice *vdev,
2161 uint32_t addr, uint32_t data)
2162 {
2163 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2164 uint8_t val = data;
2165
2166 if (addr + sizeof(val) > vdev->config_len) {
2167 return;
2168 }
2169
2170 stb_p(vdev->config + addr, val);
2171
2172 if (k->set_config) {
2173 k->set_config(vdev, vdev->config);
2174 }
2175 }
2176
2177 void virtio_config_modern_writew(VirtIODevice *vdev,
2178 uint32_t addr, uint32_t data)
2179 {
2180 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2181 uint16_t val = data;
2182
2183 if (addr + sizeof(val) > vdev->config_len) {
2184 return;
2185 }
2186
2187 stw_le_p(vdev->config + addr, val);
2188
2189 if (k->set_config) {
2190 k->set_config(vdev, vdev->config);
2191 }
2192 }
2193
2194 void virtio_config_modern_writel(VirtIODevice *vdev,
2195 uint32_t addr, uint32_t data)
2196 {
2197 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2198 uint32_t val = data;
2199
2200 if (addr + sizeof(val) > vdev->config_len) {
2201 return;
2202 }
2203
2204 stl_le_p(vdev->config + addr, val);
2205
2206 if (k->set_config) {
2207 k->set_config(vdev, vdev->config);
2208 }
2209 }
2210
2211 void virtio_queue_set_addr(VirtIODevice *vdev, int n, hwaddr addr)
2212 {
2213 if (!vdev->vq[n].vring.num) {
2214 return;
2215 }
2216 vdev->vq[n].vring.desc = addr;
2217 virtio_queue_update_rings(vdev, n);
2218 }
2219
2220 hwaddr virtio_queue_get_addr(VirtIODevice *vdev, int n)
2221 {
2222 return vdev->vq[n].vring.desc;
2223 }
2224
2225 void virtio_queue_set_rings(VirtIODevice *vdev, int n, hwaddr desc,
2226 hwaddr avail, hwaddr used)
2227 {
2228 if (!vdev->vq[n].vring.num) {
2229 return;
2230 }
2231 vdev->vq[n].vring.desc = desc;
2232 vdev->vq[n].vring.avail = avail;
2233 vdev->vq[n].vring.used = used;
2234 virtio_init_region_cache(vdev, n);
2235 }
2236
2237 void virtio_queue_set_num(VirtIODevice *vdev, int n, int num)
2238 {
2239 /* Don't allow guest to flip queue between existent and
2240 * nonexistent states, or to set it to an invalid size.
2241 */
2242 if (!!num != !!vdev->vq[n].vring.num ||
2243 num > VIRTQUEUE_MAX_SIZE ||
2244 num < 0) {
2245 return;
2246 }
2247 vdev->vq[n].vring.num = num;
2248 }
2249
2250 VirtQueue *virtio_vector_first_queue(VirtIODevice *vdev, uint16_t vector)
2251 {
2252 return QLIST_FIRST(&vdev->vector_queues[vector]);
2253 }
2254
2255 VirtQueue *virtio_vector_next_queue(VirtQueue *vq)
2256 {
2257 return QLIST_NEXT(vq, node);
2258 }
2259
2260 int virtio_queue_get_num(VirtIODevice *vdev, int n)
2261 {
2262 return vdev->vq[n].vring.num;
2263 }
2264
2265 int virtio_queue_get_max_num(VirtIODevice *vdev, int n)
2266 {
2267 return vdev->vq[n].vring.num_default;
2268 }
2269
2270 int virtio_get_num_queues(VirtIODevice *vdev)
2271 {
2272 int i;
2273
2274 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2275 if (!virtio_queue_get_num(vdev, i)) {
2276 break;
2277 }
2278 }
2279
2280 return i;
2281 }
2282
2283 void virtio_queue_set_align(VirtIODevice *vdev, int n, int align)
2284 {
2285 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2286 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2287
2288 /* virtio-1 compliant devices cannot change the alignment */
2289 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
2290 error_report("tried to modify queue alignment for virtio-1 device");
2291 return;
2292 }
2293 /* Check that the transport told us it was going to do this
2294 * (so a buggy transport will immediately assert rather than
2295 * silently failing to migrate this state)
2296 */
2297 assert(k->has_variable_vring_alignment);
2298
2299 if (align) {
2300 vdev->vq[n].vring.align = align;
2301 virtio_queue_update_rings(vdev, n);
2302 }
2303 }
2304
2305 static void virtio_queue_notify_vq(VirtQueue *vq)
2306 {
2307 if (vq->vring.desc && vq->handle_output) {
2308 VirtIODevice *vdev = vq->vdev;
2309
2310 if (unlikely(vdev->broken)) {
2311 return;
2312 }
2313
2314 trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
2315 vq->handle_output(vdev, vq);
2316
2317 if (unlikely(vdev->start_on_kick)) {
2318 virtio_set_started(vdev, true);
2319 }
2320 }
2321 }
2322
2323 void virtio_queue_notify(VirtIODevice *vdev, int n)
2324 {
2325 VirtQueue *vq = &vdev->vq[n];
2326
2327 if (unlikely(!vq->vring.desc || vdev->broken)) {
2328 return;
2329 }
2330
2331 trace_virtio_queue_notify(vdev, vq - vdev->vq, vq);
2332 if (vq->host_notifier_enabled) {
2333 event_notifier_set(&vq->host_notifier);
2334 } else if (vq->handle_output) {
2335 vq->handle_output(vdev, vq);
2336
2337 if (unlikely(vdev->start_on_kick)) {
2338 virtio_set_started(vdev, true);
2339 }
2340 }
2341 }
2342
2343 uint16_t virtio_queue_vector(VirtIODevice *vdev, int n)
2344 {
2345 return n < VIRTIO_QUEUE_MAX ? vdev->vq[n].vector :
2346 VIRTIO_NO_VECTOR;
2347 }
2348
2349 void virtio_queue_set_vector(VirtIODevice *vdev, int n, uint16_t vector)
2350 {
2351 VirtQueue *vq = &vdev->vq[n];
2352
2353 if (n < VIRTIO_QUEUE_MAX) {
2354 if (vdev->vector_queues &&
2355 vdev->vq[n].vector != VIRTIO_NO_VECTOR) {
2356 QLIST_REMOVE(vq, node);
2357 }
2358 vdev->vq[n].vector = vector;
2359 if (vdev->vector_queues &&
2360 vector != VIRTIO_NO_VECTOR) {
2361 QLIST_INSERT_HEAD(&vdev->vector_queues[vector], vq, node);
2362 }
2363 }
2364 }
2365
2366 VirtQueue *virtio_add_queue(VirtIODevice *vdev, int queue_size,
2367 VirtIOHandleOutput handle_output)
2368 {
2369 int i;
2370
2371 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2372 if (vdev->vq[i].vring.num == 0)
2373 break;
2374 }
2375
2376 if (i == VIRTIO_QUEUE_MAX || queue_size > VIRTQUEUE_MAX_SIZE)
2377 abort();
2378
2379 vdev->vq[i].vring.num = queue_size;
2380 vdev->vq[i].vring.num_default = queue_size;
2381 vdev->vq[i].vring.align = VIRTIO_PCI_VRING_ALIGN;
2382 vdev->vq[i].handle_output = handle_output;
2383 vdev->vq[i].used_elems = g_new0(VirtQueueElement, queue_size);
2384
2385 return &vdev->vq[i];
2386 }
2387
2388 void virtio_delete_queue(VirtQueue *vq)
2389 {
2390 vq->vring.num = 0;
2391 vq->vring.num_default = 0;
2392 vq->handle_output = NULL;
2393 g_free(vq->used_elems);
2394 vq->used_elems = NULL;
2395 virtio_virtqueue_reset_region_cache(vq);
2396 }
2397
2398 void virtio_del_queue(VirtIODevice *vdev, int n)
2399 {
2400 if (n < 0 || n >= VIRTIO_QUEUE_MAX) {
2401 abort();
2402 }
2403
2404 virtio_delete_queue(&vdev->vq[n]);
2405 }
2406
2407 static void virtio_set_isr(VirtIODevice *vdev, int value)
2408 {
2409 uint8_t old = qatomic_read(&vdev->isr);
2410
2411 /* Do not write ISR if it does not change, so that its cacheline remains
2412 * shared in the common case where the guest does not read it.
2413 */
2414 if ((old & value) != value) {
2415 qatomic_or(&vdev->isr, value);
2416 }
2417 }
2418
2419 /* Called within rcu_read_lock(). */
2420 static bool virtio_split_should_notify(VirtIODevice *vdev, VirtQueue *vq)
2421 {
2422 uint16_t old, new;
2423 bool v;
2424 /* We need to expose used array entries before checking used event. */
2425 smp_mb();
2426 /* Always notify when queue is empty (when feature acknowledge) */
2427 if (virtio_vdev_has_feature(vdev, VIRTIO_F_NOTIFY_ON_EMPTY) &&
2428 !vq->inuse && virtio_queue_empty(vq)) {
2429 return true;
2430 }
2431
2432 if (!virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
2433 return !(vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT);
2434 }
2435
2436 v = vq->signalled_used_valid;
2437 vq->signalled_used_valid = true;
2438 old = vq->signalled_used;
2439 new = vq->signalled_used = vq->used_idx;
2440 return !v || vring_need_event(vring_get_used_event(vq), new, old);
2441 }
2442
2443 static bool vring_packed_need_event(VirtQueue *vq, bool wrap,
2444 uint16_t off_wrap, uint16_t new,
2445 uint16_t old)
2446 {
2447 int off = off_wrap & ~(1 << 15);
2448
2449 if (wrap != off_wrap >> 15) {
2450 off -= vq->vring.num;
2451 }
2452
2453 return vring_need_event(off, new, old);
2454 }
2455
2456 /* Called within rcu_read_lock(). */
2457 static bool virtio_packed_should_notify(VirtIODevice *vdev, VirtQueue *vq)
2458 {
2459 VRingPackedDescEvent e;
2460 uint16_t old, new;
2461 bool v;
2462 VRingMemoryRegionCaches *caches;
2463
2464 caches = vring_get_region_caches(vq);
2465 if (!caches) {
2466 return false;
2467 }
2468
2469 vring_packed_event_read(vdev, &caches->avail, &e);
2470
2471 old = vq->signalled_used;
2472 new = vq->signalled_used = vq->used_idx;
2473 v = vq->signalled_used_valid;
2474 vq->signalled_used_valid = true;
2475
2476 if (e.flags == VRING_PACKED_EVENT_FLAG_DISABLE) {
2477 return false;
2478 } else if (e.flags == VRING_PACKED_EVENT_FLAG_ENABLE) {
2479 return true;
2480 }
2481
2482 return !v || vring_packed_need_event(vq, vq->used_wrap_counter,
2483 e.off_wrap, new, old);
2484 }
2485
2486 /* Called within rcu_read_lock(). */
2487 static bool virtio_should_notify(VirtIODevice *vdev, VirtQueue *vq)
2488 {
2489 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
2490 return virtio_packed_should_notify(vdev, vq);
2491 } else {
2492 return virtio_split_should_notify(vdev, vq);
2493 }
2494 }
2495
2496 void virtio_notify_irqfd(VirtIODevice *vdev, VirtQueue *vq)
2497 {
2498 WITH_RCU_READ_LOCK_GUARD() {
2499 if (!virtio_should_notify(vdev, vq)) {
2500 return;
2501 }
2502 }
2503
2504 trace_virtio_notify_irqfd(vdev, vq);
2505
2506 /*
2507 * virtio spec 1.0 says ISR bit 0 should be ignored with MSI, but
2508 * windows drivers included in virtio-win 1.8.0 (circa 2015) are
2509 * incorrectly polling this bit during crashdump and hibernation
2510 * in MSI mode, causing a hang if this bit is never updated.
2511 * Recent releases of Windows do not really shut down, but rather
2512 * log out and hibernate to make the next startup faster. Hence,
2513 * this manifested as a more serious hang during shutdown with
2514 *
2515 * Next driver release from 2016 fixed this problem, so working around it
2516 * is not a must, but it's easy to do so let's do it here.
2517 *
2518 * Note: it's safe to update ISR from any thread as it was switched
2519 * to an atomic operation.
2520 */
2521 virtio_set_isr(vq->vdev, 0x1);
2522 event_notifier_set(&vq->guest_notifier);
2523 }
2524
2525 static void virtio_irq(VirtQueue *vq)
2526 {
2527 virtio_set_isr(vq->vdev, 0x1);
2528 virtio_notify_vector(vq->vdev, vq->vector);
2529 }
2530
2531 void virtio_notify(VirtIODevice *vdev, VirtQueue *vq)
2532 {
2533 WITH_RCU_READ_LOCK_GUARD() {
2534 if (!virtio_should_notify(vdev, vq)) {
2535 return;
2536 }
2537 }
2538
2539 trace_virtio_notify(vdev, vq);
2540 virtio_irq(vq);
2541 }
2542
2543 void virtio_notify_config(VirtIODevice *vdev)
2544 {
2545 if (!(vdev->status & VIRTIO_CONFIG_S_DRIVER_OK))
2546 return;
2547
2548 virtio_set_isr(vdev, 0x3);
2549 vdev->generation++;
2550 virtio_notify_vector(vdev, vdev->config_vector);
2551 }
2552
2553 static bool virtio_device_endian_needed(void *opaque)
2554 {
2555 VirtIODevice *vdev = opaque;
2556
2557 assert(vdev->device_endian != VIRTIO_DEVICE_ENDIAN_UNKNOWN);
2558 if (!virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
2559 return vdev->device_endian != virtio_default_endian();
2560 }
2561 /* Devices conforming to VIRTIO 1.0 or later are always LE. */
2562 return vdev->device_endian != VIRTIO_DEVICE_ENDIAN_LITTLE;
2563 }
2564
2565 static bool virtio_64bit_features_needed(void *opaque)
2566 {
2567 VirtIODevice *vdev = opaque;
2568
2569 return (vdev->host_features >> 32) != 0;
2570 }
2571
2572 static bool virtio_virtqueue_needed(void *opaque)
2573 {
2574 VirtIODevice *vdev = opaque;
2575
2576 return virtio_host_has_feature(vdev, VIRTIO_F_VERSION_1);
2577 }
2578
2579 static bool virtio_packed_virtqueue_needed(void *opaque)
2580 {
2581 VirtIODevice *vdev = opaque;
2582
2583 return virtio_host_has_feature(vdev, VIRTIO_F_RING_PACKED);
2584 }
2585
2586 static bool virtio_ringsize_needed(void *opaque)
2587 {
2588 VirtIODevice *vdev = opaque;
2589 int i;
2590
2591 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2592 if (vdev->vq[i].vring.num != vdev->vq[i].vring.num_default) {
2593 return true;
2594 }
2595 }
2596 return false;
2597 }
2598
2599 static bool virtio_extra_state_needed(void *opaque)
2600 {
2601 VirtIODevice *vdev = opaque;
2602 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2603 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2604
2605 return k->has_extra_state &&
2606 k->has_extra_state(qbus->parent);
2607 }
2608
2609 static bool virtio_broken_needed(void *opaque)
2610 {
2611 VirtIODevice *vdev = opaque;
2612
2613 return vdev->broken;
2614 }
2615
2616 static bool virtio_started_needed(void *opaque)
2617 {
2618 VirtIODevice *vdev = opaque;
2619
2620 return vdev->started;
2621 }
2622
2623 static bool virtio_disabled_needed(void *opaque)
2624 {
2625 VirtIODevice *vdev = opaque;
2626
2627 return vdev->disabled;
2628 }
2629
2630 static const VMStateDescription vmstate_virtqueue = {
2631 .name = "virtqueue_state",
2632 .version_id = 1,
2633 .minimum_version_id = 1,
2634 .fields = (VMStateField[]) {
2635 VMSTATE_UINT64(vring.avail, struct VirtQueue),
2636 VMSTATE_UINT64(vring.used, struct VirtQueue),
2637 VMSTATE_END_OF_LIST()
2638 }
2639 };
2640
2641 static const VMStateDescription vmstate_packed_virtqueue = {
2642 .name = "packed_virtqueue_state",
2643 .version_id = 1,
2644 .minimum_version_id = 1,
2645 .fields = (VMStateField[]) {
2646 VMSTATE_UINT16(last_avail_idx, struct VirtQueue),
2647 VMSTATE_BOOL(last_avail_wrap_counter, struct VirtQueue),
2648 VMSTATE_UINT16(used_idx, struct VirtQueue),
2649 VMSTATE_BOOL(used_wrap_counter, struct VirtQueue),
2650 VMSTATE_UINT32(inuse, struct VirtQueue),
2651 VMSTATE_END_OF_LIST()
2652 }
2653 };
2654
2655 static const VMStateDescription vmstate_virtio_virtqueues = {
2656 .name = "virtio/virtqueues",
2657 .version_id = 1,
2658 .minimum_version_id = 1,
2659 .needed = &virtio_virtqueue_needed,
2660 .fields = (VMStateField[]) {
2661 VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice,
2662 VIRTIO_QUEUE_MAX, 0, vmstate_virtqueue, VirtQueue),
2663 VMSTATE_END_OF_LIST()
2664 }
2665 };
2666
2667 static const VMStateDescription vmstate_virtio_packed_virtqueues = {
2668 .name = "virtio/packed_virtqueues",
2669 .version_id = 1,
2670 .minimum_version_id = 1,
2671 .needed = &virtio_packed_virtqueue_needed,
2672 .fields = (VMStateField[]) {
2673 VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice,
2674 VIRTIO_QUEUE_MAX, 0, vmstate_packed_virtqueue, VirtQueue),
2675 VMSTATE_END_OF_LIST()
2676 }
2677 };
2678
2679 static const VMStateDescription vmstate_ringsize = {
2680 .name = "ringsize_state",
2681 .version_id = 1,
2682 .minimum_version_id = 1,
2683 .fields = (VMStateField[]) {
2684 VMSTATE_UINT32(vring.num_default, struct VirtQueue),
2685 VMSTATE_END_OF_LIST()
2686 }
2687 };
2688
2689 static const VMStateDescription vmstate_virtio_ringsize = {
2690 .name = "virtio/ringsize",
2691 .version_id = 1,
2692 .minimum_version_id = 1,
2693 .needed = &virtio_ringsize_needed,
2694 .fields = (VMStateField[]) {
2695 VMSTATE_STRUCT_VARRAY_POINTER_KNOWN(vq, struct VirtIODevice,
2696 VIRTIO_QUEUE_MAX, 0, vmstate_ringsize, VirtQueue),
2697 VMSTATE_END_OF_LIST()
2698 }
2699 };
2700
2701 static int get_extra_state(QEMUFile *f, void *pv, size_t size,
2702 const VMStateField *field)
2703 {
2704 VirtIODevice *vdev = pv;
2705 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2706 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2707
2708 if (!k->load_extra_state) {
2709 return -1;
2710 } else {
2711 return k->load_extra_state(qbus->parent, f);
2712 }
2713 }
2714
2715 static int put_extra_state(QEMUFile *f, void *pv, size_t size,
2716 const VMStateField *field, JSONWriter *vmdesc)
2717 {
2718 VirtIODevice *vdev = pv;
2719 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2720 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2721
2722 k->save_extra_state(qbus->parent, f);
2723 return 0;
2724 }
2725
2726 static const VMStateInfo vmstate_info_extra_state = {
2727 .name = "virtqueue_extra_state",
2728 .get = get_extra_state,
2729 .put = put_extra_state,
2730 };
2731
2732 static const VMStateDescription vmstate_virtio_extra_state = {
2733 .name = "virtio/extra_state",
2734 .version_id = 1,
2735 .minimum_version_id = 1,
2736 .needed = &virtio_extra_state_needed,
2737 .fields = (VMStateField[]) {
2738 {
2739 .name = "extra_state",
2740 .version_id = 0,
2741 .field_exists = NULL,
2742 .size = 0,
2743 .info = &vmstate_info_extra_state,
2744 .flags = VMS_SINGLE,
2745 .offset = 0,
2746 },
2747 VMSTATE_END_OF_LIST()
2748 }
2749 };
2750
2751 static const VMStateDescription vmstate_virtio_device_endian = {
2752 .name = "virtio/device_endian",
2753 .version_id = 1,
2754 .minimum_version_id = 1,
2755 .needed = &virtio_device_endian_needed,
2756 .fields = (VMStateField[]) {
2757 VMSTATE_UINT8(device_endian, VirtIODevice),
2758 VMSTATE_END_OF_LIST()
2759 }
2760 };
2761
2762 static const VMStateDescription vmstate_virtio_64bit_features = {
2763 .name = "virtio/64bit_features",
2764 .version_id = 1,
2765 .minimum_version_id = 1,
2766 .needed = &virtio_64bit_features_needed,
2767 .fields = (VMStateField[]) {
2768 VMSTATE_UINT64(guest_features, VirtIODevice),
2769 VMSTATE_END_OF_LIST()
2770 }
2771 };
2772
2773 static const VMStateDescription vmstate_virtio_broken = {
2774 .name = "virtio/broken",
2775 .version_id = 1,
2776 .minimum_version_id = 1,
2777 .needed = &virtio_broken_needed,
2778 .fields = (VMStateField[]) {
2779 VMSTATE_BOOL(broken, VirtIODevice),
2780 VMSTATE_END_OF_LIST()
2781 }
2782 };
2783
2784 static const VMStateDescription vmstate_virtio_started = {
2785 .name = "virtio/started",
2786 .version_id = 1,
2787 .minimum_version_id = 1,
2788 .needed = &virtio_started_needed,
2789 .fields = (VMStateField[]) {
2790 VMSTATE_BOOL(started, VirtIODevice),
2791 VMSTATE_END_OF_LIST()
2792 }
2793 };
2794
2795 static const VMStateDescription vmstate_virtio_disabled = {
2796 .name = "virtio/disabled",
2797 .version_id = 1,
2798 .minimum_version_id = 1,
2799 .needed = &virtio_disabled_needed,
2800 .fields = (VMStateField[]) {
2801 VMSTATE_BOOL(disabled, VirtIODevice),
2802 VMSTATE_END_OF_LIST()
2803 }
2804 };
2805
2806 static const VMStateDescription vmstate_virtio = {
2807 .name = "virtio",
2808 .version_id = 1,
2809 .minimum_version_id = 1,
2810 .fields = (VMStateField[]) {
2811 VMSTATE_END_OF_LIST()
2812 },
2813 .subsections = (const VMStateDescription*[]) {
2814 &vmstate_virtio_device_endian,
2815 &vmstate_virtio_64bit_features,
2816 &vmstate_virtio_virtqueues,
2817 &vmstate_virtio_ringsize,
2818 &vmstate_virtio_broken,
2819 &vmstate_virtio_extra_state,
2820 &vmstate_virtio_started,
2821 &vmstate_virtio_packed_virtqueues,
2822 &vmstate_virtio_disabled,
2823 NULL
2824 }
2825 };
2826
2827 int virtio_save(VirtIODevice *vdev, QEMUFile *f)
2828 {
2829 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2830 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2831 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
2832 uint32_t guest_features_lo = (vdev->guest_features & 0xffffffff);
2833 int i;
2834
2835 if (k->save_config) {
2836 k->save_config(qbus->parent, f);
2837 }
2838
2839 qemu_put_8s(f, &vdev->status);
2840 qemu_put_8s(f, &vdev->isr);
2841 qemu_put_be16s(f, &vdev->queue_sel);
2842 qemu_put_be32s(f, &guest_features_lo);
2843 qemu_put_be32(f, vdev->config_len);
2844 qemu_put_buffer(f, vdev->config, vdev->config_len);
2845
2846 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2847 if (vdev->vq[i].vring.num == 0)
2848 break;
2849 }
2850
2851 qemu_put_be32(f, i);
2852
2853 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2854 if (vdev->vq[i].vring.num == 0)
2855 break;
2856
2857 qemu_put_be32(f, vdev->vq[i].vring.num);
2858 if (k->has_variable_vring_alignment) {
2859 qemu_put_be32(f, vdev->vq[i].vring.align);
2860 }
2861 /*
2862 * Save desc now, the rest of the ring addresses are saved in
2863 * subsections for VIRTIO-1 devices.
2864 */
2865 qemu_put_be64(f, vdev->vq[i].vring.desc);
2866 qemu_put_be16s(f, &vdev->vq[i].last_avail_idx);
2867 if (k->save_queue) {
2868 k->save_queue(qbus->parent, i, f);
2869 }
2870 }
2871
2872 if (vdc->save != NULL) {
2873 vdc->save(vdev, f);
2874 }
2875
2876 if (vdc->vmsd) {
2877 int ret = vmstate_save_state(f, vdc->vmsd, vdev, NULL);
2878 if (ret) {
2879 return ret;
2880 }
2881 }
2882
2883 /* Subsections */
2884 return vmstate_save_state(f, &vmstate_virtio, vdev, NULL);
2885 }
2886
2887 /* A wrapper for use as a VMState .put function */
2888 static int virtio_device_put(QEMUFile *f, void *opaque, size_t size,
2889 const VMStateField *field, JSONWriter *vmdesc)
2890 {
2891 return virtio_save(VIRTIO_DEVICE(opaque), f);
2892 }
2893
2894 /* A wrapper for use as a VMState .get function */
2895 static int virtio_device_get(QEMUFile *f, void *opaque, size_t size,
2896 const VMStateField *field)
2897 {
2898 VirtIODevice *vdev = VIRTIO_DEVICE(opaque);
2899 DeviceClass *dc = DEVICE_CLASS(VIRTIO_DEVICE_GET_CLASS(vdev));
2900
2901 return virtio_load(vdev, f, dc->vmsd->version_id);
2902 }
2903
2904 const VMStateInfo virtio_vmstate_info = {
2905 .name = "virtio",
2906 .get = virtio_device_get,
2907 .put = virtio_device_put,
2908 };
2909
2910 static int virtio_set_features_nocheck(VirtIODevice *vdev, uint64_t val)
2911 {
2912 VirtioDeviceClass *k = VIRTIO_DEVICE_GET_CLASS(vdev);
2913 bool bad = (val & ~(vdev->host_features)) != 0;
2914
2915 val &= vdev->host_features;
2916 if (k->set_features) {
2917 k->set_features(vdev, val);
2918 }
2919 vdev->guest_features = val;
2920 return bad ? -1 : 0;
2921 }
2922
2923 int virtio_set_features(VirtIODevice *vdev, uint64_t val)
2924 {
2925 int ret;
2926 /*
2927 * The driver must not attempt to set features after feature negotiation
2928 * has finished.
2929 */
2930 if (vdev->status & VIRTIO_CONFIG_S_FEATURES_OK) {
2931 return -EINVAL;
2932 }
2933 ret = virtio_set_features_nocheck(vdev, val);
2934 if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
2935 /* VIRTIO_RING_F_EVENT_IDX changes the size of the caches. */
2936 int i;
2937 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
2938 if (vdev->vq[i].vring.num != 0) {
2939 virtio_init_region_cache(vdev, i);
2940 }
2941 }
2942 }
2943 if (!ret) {
2944 if (!virtio_device_started(vdev, vdev->status) &&
2945 !virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
2946 vdev->start_on_kick = true;
2947 }
2948 }
2949 return ret;
2950 }
2951
2952 size_t virtio_feature_get_config_size(const VirtIOFeature *feature_sizes,
2953 uint64_t host_features)
2954 {
2955 size_t config_size = 0;
2956 int i;
2957
2958 for (i = 0; feature_sizes[i].flags != 0; i++) {
2959 if (host_features & feature_sizes[i].flags) {
2960 config_size = MAX(feature_sizes[i].end, config_size);
2961 }
2962 }
2963
2964 return config_size;
2965 }
2966
2967 int virtio_load(VirtIODevice *vdev, QEMUFile *f, int version_id)
2968 {
2969 int i, ret;
2970 int32_t config_len;
2971 uint32_t num;
2972 uint32_t features;
2973 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
2974 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
2975 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(vdev);
2976
2977 /*
2978 * We poison the endianness to ensure it does not get used before
2979 * subsections have been loaded.
2980 */
2981 vdev->device_endian = VIRTIO_DEVICE_ENDIAN_UNKNOWN;
2982
2983 if (k->load_config) {
2984 ret = k->load_config(qbus->parent, f);
2985 if (ret)
2986 return ret;
2987 }
2988
2989 qemu_get_8s(f, &vdev->status);
2990 qemu_get_8s(f, &vdev->isr);
2991 qemu_get_be16s(f, &vdev->queue_sel);
2992 if (vdev->queue_sel >= VIRTIO_QUEUE_MAX) {
2993 return -1;
2994 }
2995 qemu_get_be32s(f, &features);
2996
2997 /*
2998 * Temporarily set guest_features low bits - needed by
2999 * virtio net load code testing for VIRTIO_NET_F_CTRL_GUEST_OFFLOADS
3000 * VIRTIO_NET_F_GUEST_ANNOUNCE and VIRTIO_NET_F_CTRL_VQ.
3001 *
3002 * Note: devices should always test host features in future - don't create
3003 * new dependencies like this.
3004 */
3005 vdev->guest_features = features;
3006
3007 config_len = qemu_get_be32(f);
3008
3009 /*
3010 * There are cases where the incoming config can be bigger or smaller
3011 * than what we have; so load what we have space for, and skip
3012 * any excess that's in the stream.
3013 */
3014 qemu_get_buffer(f, vdev->config, MIN(config_len, vdev->config_len));
3015
3016 while (config_len > vdev->config_len) {
3017 qemu_get_byte(f);
3018 config_len--;
3019 }
3020
3021 num = qemu_get_be32(f);
3022
3023 if (num > VIRTIO_QUEUE_MAX) {
3024 error_report("Invalid number of virtqueues: 0x%x", num);
3025 return -1;
3026 }
3027
3028 for (i = 0; i < num; i++) {
3029 vdev->vq[i].vring.num = qemu_get_be32(f);
3030 if (k->has_variable_vring_alignment) {
3031 vdev->vq[i].vring.align = qemu_get_be32(f);
3032 }
3033 vdev->vq[i].vring.desc = qemu_get_be64(f);
3034 qemu_get_be16s(f, &vdev->vq[i].last_avail_idx);
3035 vdev->vq[i].signalled_used_valid = false;
3036 vdev->vq[i].notification = true;
3037
3038 if (!vdev->vq[i].vring.desc && vdev->vq[i].last_avail_idx) {
3039 error_report("VQ %d address 0x0 "
3040 "inconsistent with Host index 0x%x",
3041 i, vdev->vq[i].last_avail_idx);
3042 return -1;
3043 }
3044 if (k->load_queue) {
3045 ret = k->load_queue(qbus->parent, i, f);
3046 if (ret)
3047 return ret;
3048 }
3049 }
3050
3051 virtio_notify_vector(vdev, VIRTIO_NO_VECTOR);
3052
3053 if (vdc->load != NULL) {
3054 ret = vdc->load(vdev, f, version_id);
3055 if (ret) {
3056 return ret;
3057 }
3058 }
3059
3060 if (vdc->vmsd) {
3061 ret = vmstate_load_state(f, vdc->vmsd, vdev, version_id);
3062 if (ret) {
3063 return ret;
3064 }
3065 }
3066
3067 /* Subsections */
3068 ret = vmstate_load_state(f, &vmstate_virtio, vdev, 1);
3069 if (ret) {
3070 return ret;
3071 }
3072
3073 if (vdev->device_endian == VIRTIO_DEVICE_ENDIAN_UNKNOWN) {
3074 vdev->device_endian = virtio_default_endian();
3075 }
3076
3077 if (virtio_64bit_features_needed(vdev)) {
3078 /*
3079 * Subsection load filled vdev->guest_features. Run them
3080 * through virtio_set_features to sanity-check them against
3081 * host_features.
3082 */
3083 uint64_t features64 = vdev->guest_features;
3084 if (virtio_set_features_nocheck(vdev, features64) < 0) {
3085 error_report("Features 0x%" PRIx64 " unsupported. "
3086 "Allowed features: 0x%" PRIx64,
3087 features64, vdev->host_features);
3088 return -1;
3089 }
3090 } else {
3091 if (virtio_set_features_nocheck(vdev, features) < 0) {
3092 error_report("Features 0x%x unsupported. "
3093 "Allowed features: 0x%" PRIx64,
3094 features, vdev->host_features);
3095 return -1;
3096 }
3097 }
3098
3099 if (!virtio_device_started(vdev, vdev->status) &&
3100 !virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
3101 vdev->start_on_kick = true;
3102 }
3103
3104 RCU_READ_LOCK_GUARD();
3105 for (i = 0; i < num; i++) {
3106 if (vdev->vq[i].vring.desc) {
3107 uint16_t nheads;
3108
3109 /*
3110 * VIRTIO-1 devices migrate desc, used, and avail ring addresses so
3111 * only the region cache needs to be set up. Legacy devices need
3112 * to calculate used and avail ring addresses based on the desc
3113 * address.
3114 */
3115 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
3116 virtio_init_region_cache(vdev, i);
3117 } else {
3118 virtio_queue_update_rings(vdev, i);
3119 }
3120
3121 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3122 vdev->vq[i].shadow_avail_idx = vdev->vq[i].last_avail_idx;
3123 vdev->vq[i].shadow_avail_wrap_counter =
3124 vdev->vq[i].last_avail_wrap_counter;
3125 continue;
3126 }
3127
3128 nheads = vring_avail_idx(&vdev->vq[i]) - vdev->vq[i].last_avail_idx;
3129 /* Check it isn't doing strange things with descriptor numbers. */
3130 if (nheads > vdev->vq[i].vring.num) {
3131 virtio_error(vdev, "VQ %d size 0x%x Guest index 0x%x "
3132 "inconsistent with Host index 0x%x: delta 0x%x",
3133 i, vdev->vq[i].vring.num,
3134 vring_avail_idx(&vdev->vq[i]),
3135 vdev->vq[i].last_avail_idx, nheads);
3136 vdev->vq[i].used_idx = 0;
3137 vdev->vq[i].shadow_avail_idx = 0;
3138 vdev->vq[i].inuse = 0;
3139 continue;
3140 }
3141 vdev->vq[i].used_idx = vring_used_idx(&vdev->vq[i]);
3142 vdev->vq[i].shadow_avail_idx = vring_avail_idx(&vdev->vq[i]);
3143
3144 /*
3145 * Some devices migrate VirtQueueElements that have been popped
3146 * from the avail ring but not yet returned to the used ring.
3147 * Since max ring size < UINT16_MAX it's safe to use modulo
3148 * UINT16_MAX + 1 subtraction.
3149 */
3150 vdev->vq[i].inuse = (uint16_t)(vdev->vq[i].last_avail_idx -
3151 vdev->vq[i].used_idx);
3152 if (vdev->vq[i].inuse > vdev->vq[i].vring.num) {
3153 error_report("VQ %d size 0x%x < last_avail_idx 0x%x - "
3154 "used_idx 0x%x",
3155 i, vdev->vq[i].vring.num,
3156 vdev->vq[i].last_avail_idx,
3157 vdev->vq[i].used_idx);
3158 return -1;
3159 }
3160 }
3161 }
3162
3163 if (vdc->post_load) {
3164 ret = vdc->post_load(vdev);
3165 if (ret) {
3166 return ret;
3167 }
3168 }
3169
3170 return 0;
3171 }
3172
3173 void virtio_cleanup(VirtIODevice *vdev)
3174 {
3175 qemu_del_vm_change_state_handler(vdev->vmstate);
3176 }
3177
3178 static void virtio_vmstate_change(void *opaque, bool running, RunState state)
3179 {
3180 VirtIODevice *vdev = opaque;
3181 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3182 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
3183 bool backend_run = running && virtio_device_started(vdev, vdev->status);
3184 vdev->vm_running = running;
3185
3186 if (backend_run) {
3187 virtio_set_status(vdev, vdev->status);
3188 }
3189
3190 if (k->vmstate_change) {
3191 k->vmstate_change(qbus->parent, backend_run);
3192 }
3193
3194 if (!backend_run) {
3195 virtio_set_status(vdev, vdev->status);
3196 }
3197 }
3198
3199 void virtio_instance_init_common(Object *proxy_obj, void *data,
3200 size_t vdev_size, const char *vdev_name)
3201 {
3202 DeviceState *vdev = data;
3203
3204 object_initialize_child_with_props(proxy_obj, "virtio-backend", vdev,
3205 vdev_size, vdev_name, &error_abort,
3206 NULL);
3207 qdev_alias_all_properties(vdev, proxy_obj);
3208 }
3209
3210 void virtio_init(VirtIODevice *vdev, const char *name,
3211 uint16_t device_id, size_t config_size)
3212 {
3213 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3214 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
3215 int i;
3216 int nvectors = k->query_nvectors ? k->query_nvectors(qbus->parent) : 0;
3217
3218 if (nvectors) {
3219 vdev->vector_queues =
3220 g_malloc0(sizeof(*vdev->vector_queues) * nvectors);
3221 }
3222
3223 vdev->start_on_kick = false;
3224 vdev->started = false;
3225 vdev->device_id = device_id;
3226 vdev->status = 0;
3227 qatomic_set(&vdev->isr, 0);
3228 vdev->queue_sel = 0;
3229 vdev->config_vector = VIRTIO_NO_VECTOR;
3230 vdev->vq = g_new0(VirtQueue, VIRTIO_QUEUE_MAX);
3231 vdev->vm_running = runstate_is_running();
3232 vdev->broken = false;
3233 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
3234 vdev->vq[i].vector = VIRTIO_NO_VECTOR;
3235 vdev->vq[i].vdev = vdev;
3236 vdev->vq[i].queue_index = i;
3237 vdev->vq[i].host_notifier_enabled = false;
3238 }
3239
3240 vdev->name = name;
3241 vdev->config_len = config_size;
3242 if (vdev->config_len) {
3243 vdev->config = g_malloc0(config_size);
3244 } else {
3245 vdev->config = NULL;
3246 }
3247 vdev->vmstate = qdev_add_vm_change_state_handler(DEVICE(vdev),
3248 virtio_vmstate_change, vdev);
3249 vdev->device_endian = virtio_default_endian();
3250 vdev->use_guest_notifier_mask = true;
3251 }
3252
3253 /*
3254 * Only devices that have already been around prior to defining the virtio
3255 * standard support legacy mode; this includes devices not specified in the
3256 * standard. All newer devices conform to the virtio standard only.
3257 */
3258 bool virtio_legacy_allowed(VirtIODevice *vdev)
3259 {
3260 switch (vdev->device_id) {
3261 case VIRTIO_ID_NET:
3262 case VIRTIO_ID_BLOCK:
3263 case VIRTIO_ID_CONSOLE:
3264 case VIRTIO_ID_RNG:
3265 case VIRTIO_ID_BALLOON:
3266 case VIRTIO_ID_RPMSG:
3267 case VIRTIO_ID_SCSI:
3268 case VIRTIO_ID_9P:
3269 case VIRTIO_ID_RPROC_SERIAL:
3270 case VIRTIO_ID_CAIF:
3271 return true;
3272 default:
3273 return false;
3274 }
3275 }
3276
3277 bool virtio_legacy_check_disabled(VirtIODevice *vdev)
3278 {
3279 return vdev->disable_legacy_check;
3280 }
3281
3282 hwaddr virtio_queue_get_desc_addr(VirtIODevice *vdev, int n)
3283 {
3284 return vdev->vq[n].vring.desc;
3285 }
3286
3287 bool virtio_queue_enabled_legacy(VirtIODevice *vdev, int n)
3288 {
3289 return virtio_queue_get_desc_addr(vdev, n) != 0;
3290 }
3291
3292 bool virtio_queue_enabled(VirtIODevice *vdev, int n)
3293 {
3294 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3295 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
3296
3297 if (k->queue_enabled) {
3298 return k->queue_enabled(qbus->parent, n);
3299 }
3300 return virtio_queue_enabled_legacy(vdev, n);
3301 }
3302
3303 hwaddr virtio_queue_get_avail_addr(VirtIODevice *vdev, int n)
3304 {
3305 return vdev->vq[n].vring.avail;
3306 }
3307
3308 hwaddr virtio_queue_get_used_addr(VirtIODevice *vdev, int n)
3309 {
3310 return vdev->vq[n].vring.used;
3311 }
3312
3313 hwaddr virtio_queue_get_desc_size(VirtIODevice *vdev, int n)
3314 {
3315 return sizeof(VRingDesc) * vdev->vq[n].vring.num;
3316 }
3317
3318 hwaddr virtio_queue_get_avail_size(VirtIODevice *vdev, int n)
3319 {
3320 int s;
3321
3322 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3323 return sizeof(struct VRingPackedDescEvent);
3324 }
3325
3326 s = virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
3327 return offsetof(VRingAvail, ring) +
3328 sizeof(uint16_t) * vdev->vq[n].vring.num + s;
3329 }
3330
3331 hwaddr virtio_queue_get_used_size(VirtIODevice *vdev, int n)
3332 {
3333 int s;
3334
3335 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3336 return sizeof(struct VRingPackedDescEvent);
3337 }
3338
3339 s = virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
3340 return offsetof(VRingUsed, ring) +
3341 sizeof(VRingUsedElem) * vdev->vq[n].vring.num + s;
3342 }
3343
3344 static unsigned int virtio_queue_packed_get_last_avail_idx(VirtIODevice *vdev,
3345 int n)
3346 {
3347 unsigned int avail, used;
3348
3349 avail = vdev->vq[n].last_avail_idx;
3350 avail |= ((uint16_t)vdev->vq[n].last_avail_wrap_counter) << 15;
3351
3352 used = vdev->vq[n].used_idx;
3353 used |= ((uint16_t)vdev->vq[n].used_wrap_counter) << 15;
3354
3355 return avail | used << 16;
3356 }
3357
3358 static uint16_t virtio_queue_split_get_last_avail_idx(VirtIODevice *vdev,
3359 int n)
3360 {
3361 return vdev->vq[n].last_avail_idx;
3362 }
3363
3364 unsigned int virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n)
3365 {
3366 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3367 return virtio_queue_packed_get_last_avail_idx(vdev, n);
3368 } else {
3369 return virtio_queue_split_get_last_avail_idx(vdev, n);
3370 }
3371 }
3372
3373 static void virtio_queue_packed_set_last_avail_idx(VirtIODevice *vdev,
3374 int n, unsigned int idx)
3375 {
3376 struct VirtQueue *vq = &vdev->vq[n];
3377
3378 vq->last_avail_idx = vq->shadow_avail_idx = idx & 0x7fff;
3379 vq->last_avail_wrap_counter =
3380 vq->shadow_avail_wrap_counter = !!(idx & 0x8000);
3381 idx >>= 16;
3382 vq->used_idx = idx & 0x7ffff;
3383 vq->used_wrap_counter = !!(idx & 0x8000);
3384 }
3385
3386 static void virtio_queue_split_set_last_avail_idx(VirtIODevice *vdev,
3387 int n, unsigned int idx)
3388 {
3389 vdev->vq[n].last_avail_idx = idx;
3390 vdev->vq[n].shadow_avail_idx = idx;
3391 }
3392
3393 void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n,
3394 unsigned int idx)
3395 {
3396 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3397 virtio_queue_packed_set_last_avail_idx(vdev, n, idx);
3398 } else {
3399 virtio_queue_split_set_last_avail_idx(vdev, n, idx);
3400 }
3401 }
3402
3403 static void virtio_queue_packed_restore_last_avail_idx(VirtIODevice *vdev,
3404 int n)
3405 {
3406 /* We don't have a reference like avail idx in shared memory */
3407 return;
3408 }
3409
3410 static void virtio_queue_split_restore_last_avail_idx(VirtIODevice *vdev,
3411 int n)
3412 {
3413 RCU_READ_LOCK_GUARD();
3414 if (vdev->vq[n].vring.desc) {
3415 vdev->vq[n].last_avail_idx = vring_used_idx(&vdev->vq[n]);
3416 vdev->vq[n].shadow_avail_idx = vdev->vq[n].last_avail_idx;
3417 }
3418 }
3419
3420 void virtio_queue_restore_last_avail_idx(VirtIODevice *vdev, int n)
3421 {
3422 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3423 virtio_queue_packed_restore_last_avail_idx(vdev, n);
3424 } else {
3425 virtio_queue_split_restore_last_avail_idx(vdev, n);
3426 }
3427 }
3428
3429 static void virtio_queue_packed_update_used_idx(VirtIODevice *vdev, int n)
3430 {
3431 /* used idx was updated through set_last_avail_idx() */
3432 return;
3433 }
3434
3435 static void virtio_split_packed_update_used_idx(VirtIODevice *vdev, int n)
3436 {
3437 RCU_READ_LOCK_GUARD();
3438 if (vdev->vq[n].vring.desc) {
3439 vdev->vq[n].used_idx = vring_used_idx(&vdev->vq[n]);
3440 }
3441 }
3442
3443 void virtio_queue_update_used_idx(VirtIODevice *vdev, int n)
3444 {
3445 if (virtio_vdev_has_feature(vdev, VIRTIO_F_RING_PACKED)) {
3446 return virtio_queue_packed_update_used_idx(vdev, n);
3447 } else {
3448 return virtio_split_packed_update_used_idx(vdev, n);
3449 }
3450 }
3451
3452 void virtio_queue_invalidate_signalled_used(VirtIODevice *vdev, int n)
3453 {
3454 vdev->vq[n].signalled_used_valid = false;
3455 }
3456
3457 VirtQueue *virtio_get_queue(VirtIODevice *vdev, int n)
3458 {
3459 return vdev->vq + n;
3460 }
3461
3462 uint16_t virtio_get_queue_index(VirtQueue *vq)
3463 {
3464 return vq->queue_index;
3465 }
3466
3467 static void virtio_queue_guest_notifier_read(EventNotifier *n)
3468 {
3469 VirtQueue *vq = container_of(n, VirtQueue, guest_notifier);
3470 if (event_notifier_test_and_clear(n)) {
3471 virtio_irq(vq);
3472 }
3473 }
3474
3475 void virtio_queue_set_guest_notifier_fd_handler(VirtQueue *vq, bool assign,
3476 bool with_irqfd)
3477 {
3478 if (assign && !with_irqfd) {
3479 event_notifier_set_handler(&vq->guest_notifier,
3480 virtio_queue_guest_notifier_read);
3481 } else {
3482 event_notifier_set_handler(&vq->guest_notifier, NULL);
3483 }
3484 if (!assign) {
3485 /* Test and clear notifier before closing it,
3486 * in case poll callback didn't have time to run. */
3487 virtio_queue_guest_notifier_read(&vq->guest_notifier);
3488 }
3489 }
3490
3491 EventNotifier *virtio_queue_get_guest_notifier(VirtQueue *vq)
3492 {
3493 return &vq->guest_notifier;
3494 }
3495
3496 static void virtio_queue_host_notifier_aio_poll_begin(EventNotifier *n)
3497 {
3498 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
3499
3500 virtio_queue_set_notification(vq, 0);
3501 }
3502
3503 static bool virtio_queue_host_notifier_aio_poll(void *opaque)
3504 {
3505 EventNotifier *n = opaque;
3506 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
3507
3508 return vq->vring.desc && !virtio_queue_empty(vq);
3509 }
3510
3511 static void virtio_queue_host_notifier_aio_poll_ready(EventNotifier *n)
3512 {
3513 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
3514
3515 virtio_queue_notify_vq(vq);
3516 }
3517
3518 static void virtio_queue_host_notifier_aio_poll_end(EventNotifier *n)
3519 {
3520 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
3521
3522 /* Caller polls once more after this to catch requests that race with us */
3523 virtio_queue_set_notification(vq, 1);
3524 }
3525
3526 void virtio_queue_aio_attach_host_notifier(VirtQueue *vq, AioContext *ctx)
3527 {
3528 aio_set_event_notifier(ctx, &vq->host_notifier, true,
3529 virtio_queue_host_notifier_read,
3530 virtio_queue_host_notifier_aio_poll,
3531 virtio_queue_host_notifier_aio_poll_ready);
3532 aio_set_event_notifier_poll(ctx, &vq->host_notifier,
3533 virtio_queue_host_notifier_aio_poll_begin,
3534 virtio_queue_host_notifier_aio_poll_end);
3535 }
3536
3537 void virtio_queue_aio_detach_host_notifier(VirtQueue *vq, AioContext *ctx)
3538 {
3539 aio_set_event_notifier(ctx, &vq->host_notifier, true, NULL, NULL, NULL);
3540 /* Test and clear notifier before after disabling event,
3541 * in case poll callback didn't have time to run. */
3542 virtio_queue_host_notifier_read(&vq->host_notifier);
3543 }
3544
3545 void virtio_queue_host_notifier_read(EventNotifier *n)
3546 {
3547 VirtQueue *vq = container_of(n, VirtQueue, host_notifier);
3548 if (event_notifier_test_and_clear(n)) {
3549 virtio_queue_notify_vq(vq);
3550 }
3551 }
3552
3553 EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq)
3554 {
3555 return &vq->host_notifier;
3556 }
3557
3558 void virtio_queue_set_host_notifier_enabled(VirtQueue *vq, bool enabled)
3559 {
3560 vq->host_notifier_enabled = enabled;
3561 }
3562
3563 int virtio_queue_set_host_notifier_mr(VirtIODevice *vdev, int n,
3564 MemoryRegion *mr, bool assign)
3565 {
3566 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3567 VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
3568
3569 if (k->set_host_notifier_mr) {
3570 return k->set_host_notifier_mr(qbus->parent, n, mr, assign);
3571 }
3572
3573 return -1;
3574 }
3575
3576 void virtio_device_set_child_bus_name(VirtIODevice *vdev, char *bus_name)
3577 {
3578 g_free(vdev->bus_name);
3579 vdev->bus_name = g_strdup(bus_name);
3580 }
3581
3582 void G_GNUC_PRINTF(2, 3) virtio_error(VirtIODevice *vdev, const char *fmt, ...)
3583 {
3584 va_list ap;
3585
3586 va_start(ap, fmt);
3587 error_vreport(fmt, ap);
3588 va_end(ap);
3589
3590 if (virtio_vdev_has_feature(vdev, VIRTIO_F_VERSION_1)) {
3591 vdev->status = vdev->status | VIRTIO_CONFIG_S_NEEDS_RESET;
3592 virtio_notify_config(vdev);
3593 }
3594
3595 vdev->broken = true;
3596 }
3597
3598 static void virtio_memory_listener_commit(MemoryListener *listener)
3599 {
3600 VirtIODevice *vdev = container_of(listener, VirtIODevice, listener);
3601 int i;
3602
3603 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
3604 if (vdev->vq[i].vring.num == 0) {
3605 break;
3606 }
3607 virtio_init_region_cache(vdev, i);
3608 }
3609 }
3610
3611 static void virtio_device_realize(DeviceState *dev, Error **errp)
3612 {
3613 VirtIODevice *vdev = VIRTIO_DEVICE(dev);
3614 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev);
3615 Error *err = NULL;
3616
3617 /* Devices should either use vmsd or the load/save methods */
3618 assert(!vdc->vmsd || !vdc->load);
3619
3620 if (vdc->realize != NULL) {
3621 vdc->realize(dev, &err);
3622 if (err != NULL) {
3623 error_propagate(errp, err);
3624 return;
3625 }
3626 }
3627
3628 virtio_bus_device_plugged(vdev, &err);
3629 if (err != NULL) {
3630 error_propagate(errp, err);
3631 vdc->unrealize(dev);
3632 return;
3633 }
3634
3635 vdev->listener.commit = virtio_memory_listener_commit;
3636 vdev->listener.name = "virtio";
3637 memory_listener_register(&vdev->listener, vdev->dma_as);
3638 }
3639
3640 static void virtio_device_unrealize(DeviceState *dev)
3641 {
3642 VirtIODevice *vdev = VIRTIO_DEVICE(dev);
3643 VirtioDeviceClass *vdc = VIRTIO_DEVICE_GET_CLASS(dev);
3644
3645 memory_listener_unregister(&vdev->listener);
3646 virtio_bus_device_unplugged(vdev);
3647
3648 if (vdc->unrealize != NULL) {
3649 vdc->unrealize(dev);
3650 }
3651
3652 g_free(vdev->bus_name);
3653 vdev->bus_name = NULL;
3654 }
3655
3656 static void virtio_device_free_virtqueues(VirtIODevice *vdev)
3657 {
3658 int i;
3659 if (!vdev->vq) {
3660 return;
3661 }
3662
3663 for (i = 0; i < VIRTIO_QUEUE_MAX; i++) {
3664 if (vdev->vq[i].vring.num == 0) {
3665 break;
3666 }
3667 virtio_virtqueue_reset_region_cache(&vdev->vq[i]);
3668 }
3669 g_free(vdev->vq);
3670 }
3671
3672 static void virtio_device_instance_finalize(Object *obj)
3673 {
3674 VirtIODevice *vdev = VIRTIO_DEVICE(obj);
3675
3676 virtio_device_free_virtqueues(vdev);
3677
3678 g_free(vdev->config);
3679 g_free(vdev->vector_queues);
3680 }
3681
3682 static Property virtio_properties[] = {
3683 DEFINE_VIRTIO_COMMON_FEATURES(VirtIODevice, host_features),
3684 DEFINE_PROP_BOOL("use-started", VirtIODevice, use_started, true),
3685 DEFINE_PROP_BOOL("use-disabled-flag", VirtIODevice, use_disabled_flag, true),
3686 DEFINE_PROP_BOOL("x-disable-legacy-check", VirtIODevice,
3687 disable_legacy_check, false),
3688 DEFINE_PROP_END_OF_LIST(),
3689 };
3690
3691 static int virtio_device_start_ioeventfd_impl(VirtIODevice *vdev)
3692 {
3693 VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev)));
3694 int i, n, r, err;
3695
3696 /*
3697 * Batch all the host notifiers in a single transaction to avoid
3698 * quadratic time complexity in address_space_update_ioeventfds().
3699 */
3700 memory_region_transaction_begin();
3701 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
3702 VirtQueue *vq = &vdev->vq[n];
3703 if (!virtio_queue_get_num(vdev, n)) {
3704 continue;
3705 }
3706 r = virtio_bus_set_host_notifier(qbus, n, true);
3707 if (r < 0) {
3708 err = r;
3709 goto assign_error;
3710 }
3711 event_notifier_set_handler(&vq->host_notifier,
3712 virtio_queue_host_notifier_read);
3713 }
3714
3715 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
3716 /* Kick right away to begin processing requests already in vring */
3717 VirtQueue *vq = &vdev->vq[n];
3718 if (!vq->vring.num) {
3719 continue;
3720 }
3721 event_notifier_set(&vq->host_notifier);
3722 }
3723 memory_region_transaction_commit();
3724 return 0;
3725
3726 assign_error:
3727 i = n; /* save n for a second iteration after transaction is committed. */
3728 while (--n >= 0) {
3729 VirtQueue *vq = &vdev->vq[n];
3730 if (!virtio_queue_get_num(vdev, n)) {
3731 continue;
3732 }
3733
3734 event_notifier_set_handler(&vq->host_notifier, NULL);
3735 r = virtio_bus_set_host_notifier(qbus, n, false);
3736 assert(r >= 0);
3737 }
3738 /*
3739 * The transaction expects the ioeventfds to be open when it
3740 * commits. Do it now, before the cleanup loop.
3741 */
3742 memory_region_transaction_commit();
3743
3744 while (--i >= 0) {
3745 if (!virtio_queue_get_num(vdev, i)) {
3746 continue;
3747 }
3748 virtio_bus_cleanup_host_notifier(qbus, i);
3749 }
3750 return err;
3751 }
3752
3753 int virtio_device_start_ioeventfd(VirtIODevice *vdev)
3754 {
3755 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3756 VirtioBusState *vbus = VIRTIO_BUS(qbus);
3757
3758 return virtio_bus_start_ioeventfd(vbus);
3759 }
3760
3761 static void virtio_device_stop_ioeventfd_impl(VirtIODevice *vdev)
3762 {
3763 VirtioBusState *qbus = VIRTIO_BUS(qdev_get_parent_bus(DEVICE(vdev)));
3764 int n, r;
3765
3766 /*
3767 * Batch all the host notifiers in a single transaction to avoid
3768 * quadratic time complexity in address_space_update_ioeventfds().
3769 */
3770 memory_region_transaction_begin();
3771 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
3772 VirtQueue *vq = &vdev->vq[n];
3773
3774 if (!virtio_queue_get_num(vdev, n)) {
3775 continue;
3776 }
3777 event_notifier_set_handler(&vq->host_notifier, NULL);
3778 r = virtio_bus_set_host_notifier(qbus, n, false);
3779 assert(r >= 0);
3780 }
3781 /*
3782 * The transaction expects the ioeventfds to be open when it
3783 * commits. Do it now, before the cleanup loop.
3784 */
3785 memory_region_transaction_commit();
3786
3787 for (n = 0; n < VIRTIO_QUEUE_MAX; n++) {
3788 if (!virtio_queue_get_num(vdev, n)) {
3789 continue;
3790 }
3791 virtio_bus_cleanup_host_notifier(qbus, n);
3792 }
3793 }
3794
3795 int virtio_device_grab_ioeventfd(VirtIODevice *vdev)
3796 {
3797 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3798 VirtioBusState *vbus = VIRTIO_BUS(qbus);
3799
3800 return virtio_bus_grab_ioeventfd(vbus);
3801 }
3802
3803 void virtio_device_release_ioeventfd(VirtIODevice *vdev)
3804 {
3805 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3806 VirtioBusState *vbus = VIRTIO_BUS(qbus);
3807
3808 virtio_bus_release_ioeventfd(vbus);
3809 }
3810
3811 static void virtio_device_class_init(ObjectClass *klass, void *data)
3812 {
3813 /* Set the default value here. */
3814 VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
3815 DeviceClass *dc = DEVICE_CLASS(klass);
3816
3817 dc->realize = virtio_device_realize;
3818 dc->unrealize = virtio_device_unrealize;
3819 dc->bus_type = TYPE_VIRTIO_BUS;
3820 device_class_set_props(dc, virtio_properties);
3821 vdc->start_ioeventfd = virtio_device_start_ioeventfd_impl;
3822 vdc->stop_ioeventfd = virtio_device_stop_ioeventfd_impl;
3823
3824 vdc->legacy_features |= VIRTIO_LEGACY_FEATURES;
3825 }
3826
3827 bool virtio_device_ioeventfd_enabled(VirtIODevice *vdev)
3828 {
3829 BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
3830 VirtioBusState *vbus = VIRTIO_BUS(qbus);
3831
3832 return virtio_bus_ioeventfd_enabled(vbus);
3833 }
3834
3835 static const TypeInfo virtio_device_info = {
3836 .name = TYPE_VIRTIO_DEVICE,
3837 .parent = TYPE_DEVICE,
3838 .instance_size = sizeof(VirtIODevice),
3839 .class_init = virtio_device_class_init,
3840 .instance_finalize = virtio_device_instance_finalize,
3841 .abstract = true,
3842 .class_size = sizeof(VirtioDeviceClass),
3843 };
3844
3845 static void virtio_register_types(void)
3846 {
3847 type_register_static(&virtio_device_info);
3848 }
3849
3850 type_init(virtio_register_types)
armbru's QEMU hackery