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19#include <linux/virtio.h>
20#include <linux/virtio_ring.h>
21#include <linux/virtio_config.h>
22#include <linux/device.h>
23#include <linux/slab.h>
24#include <linux/module.h>
25#include <linux/hrtimer.h>
26
27#ifdef DEBUG
28
29#define BAD_RING(_vq, fmt, args...) \
30 do { \
31 dev_err(&(_vq)->vq.vdev->dev, \
32 "%s:"fmt, (_vq)->vq.name, ##args); \
33 BUG(); \
34 } while (0)
35
36#define START_USE(_vq) \
37 do { \
38 if ((_vq)->in_use) \
39 panic("%s:in_use = %i\n", \
40 (_vq)->vq.name, (_vq)->in_use); \
41 (_vq)->in_use = __LINE__; \
42 } while (0)
43#define END_USE(_vq) \
44 do { BUG_ON(!(_vq)->in_use); (_vq)->in_use = 0; } while(0)
45#else
46#define BAD_RING(_vq, fmt, args...) \
47 do { \
48 dev_err(&_vq->vq.vdev->dev, \
49 "%s:"fmt, (_vq)->vq.name, ##args); \
50 (_vq)->broken = true; \
51 } while (0)
52#define START_USE(vq)
53#define END_USE(vq)
54#endif
55
56struct vring_virtqueue
57{
58 struct virtqueue vq;
59
60
61 struct vring vring;
62
63
64 bool weak_barriers;
65
66
67 bool broken;
68
69
70 bool indirect;
71
72
73 bool event;
74
75
76 unsigned int free_head;
77
78 unsigned int num_added;
79
80
81 u16 last_used_idx;
82
83
84 void (*notify)(struct virtqueue *vq);
85
86#ifdef DEBUG
87
88 unsigned int in_use;
89
90
91 bool last_add_time_valid;
92 ktime_t last_add_time;
93#endif
94
95
96 void *data[];
97};
98
99#define to_vvq(_vq) container_of(_vq, struct vring_virtqueue, vq)
100
101static inline struct scatterlist *sg_next_chained(struct scatterlist *sg,
102 unsigned int *count)
103{
104 return sg_next(sg);
105}
106
107static inline struct scatterlist *sg_next_arr(struct scatterlist *sg,
108 unsigned int *count)
109{
110 if (--(*count) == 0)
111 return NULL;
112 return sg + 1;
113}
114
115
116static inline int vring_add_indirect(struct vring_virtqueue *vq,
117 struct scatterlist *sgs[],
118 struct scatterlist *(*next)
119 (struct scatterlist *, unsigned int *),
120 unsigned int total_sg,
121 unsigned int total_out,
122 unsigned int total_in,
123 unsigned int out_sgs,
124 unsigned int in_sgs,
125 gfp_t gfp)
126{
127 struct vring_desc *desc;
128 unsigned head;
129 struct scatterlist *sg;
130 int i, n;
131
132
133
134
135
136
137 gfp &= ~(__GFP_HIGHMEM | __GFP_HIGH);
138
139 desc = kmalloc(total_sg * sizeof(struct vring_desc), gfp);
140 if (!desc)
141 return -ENOMEM;
142
143
144 i = 0;
145 for (n = 0; n < out_sgs; n++) {
146 for (sg = sgs[n]; sg; sg = next(sg, &total_out)) {
147 desc[i].flags = VRING_DESC_F_NEXT;
148 desc[i].addr = sg_phys(sg);
149 desc[i].len = sg->length;
150 desc[i].next = i+1;
151 i++;
152 }
153 }
154 for (; n < (out_sgs + in_sgs); n++) {
155 for (sg = sgs[n]; sg; sg = next(sg, &total_in)) {
156 desc[i].flags = VRING_DESC_F_NEXT|VRING_DESC_F_WRITE;
157 desc[i].addr = sg_phys(sg);
158 desc[i].len = sg->length;
159 desc[i].next = i+1;
160 i++;
161 }
162 }
163 BUG_ON(i != total_sg);
164
165
166 desc[i-1].flags &= ~VRING_DESC_F_NEXT;
167 desc[i-1].next = 0;
168
169
170 vq->vq.num_free--;
171
172
173 head = vq->free_head;
174 vq->vring.desc[head].flags = VRING_DESC_F_INDIRECT;
175 vq->vring.desc[head].addr = virt_to_phys(desc);
176 vq->vring.desc[head].len = i * sizeof(struct vring_desc);
177
178
179 vq->free_head = vq->vring.desc[head].next;
180
181 return head;
182}
183
184static inline int virtqueue_add(struct virtqueue *_vq,
185 struct scatterlist *sgs[],
186 struct scatterlist *(*next)
187 (struct scatterlist *, unsigned int *),
188 unsigned int total_out,
189 unsigned int total_in,
190 unsigned int out_sgs,
191 unsigned int in_sgs,
192 void *data,
193 gfp_t gfp)
194{
195 struct vring_virtqueue *vq = to_vvq(_vq);
196 struct scatterlist *sg;
197 unsigned int i, n, avail, uninitialized_var(prev), total_sg;
198 int head;
199
200 START_USE(vq);
201
202 BUG_ON(data == NULL);
203
204#ifdef DEBUG
205 {
206 ktime_t now = ktime_get();
207
208
209 if (vq->last_add_time_valid)
210 WARN_ON(ktime_to_ms(ktime_sub(now, vq->last_add_time))
211 > 100);
212 vq->last_add_time = now;
213 vq->last_add_time_valid = true;
214 }
215#endif
216
217 total_sg = total_in + total_out;
218
219
220
221 if (vq->indirect && total_sg > 1 && vq->vq.num_free) {
222 head = vring_add_indirect(vq, sgs, next, total_sg, total_out,
223 total_in,
224 out_sgs, in_sgs, gfp);
225 if (likely(head >= 0))
226 goto add_head;
227 }
228
229 BUG_ON(total_sg > vq->vring.num);
230 BUG_ON(total_sg == 0);
231
232 if (vq->vq.num_free < total_sg) {
233 pr_debug("Can't add buf len %i - avail = %i\n",
234 total_sg, vq->vq.num_free);
235
236
237
238 if (out_sgs)
239 vq->notify(&vq->vq);
240 END_USE(vq);
241 return -ENOSPC;
242 }
243
244
245 vq->vq.num_free -= total_sg;
246
247 head = i = vq->free_head;
248 for (n = 0; n < out_sgs; n++) {
249 for (sg = sgs[n]; sg; sg = next(sg, &total_out)) {
250 vq->vring.desc[i].flags = VRING_DESC_F_NEXT;
251 vq->vring.desc[i].addr = sg_phys(sg);
252 vq->vring.desc[i].len = sg->length;
253 prev = i;
254 i = vq->vring.desc[i].next;
255 }
256 }
257 for (; n < (out_sgs + in_sgs); n++) {
258 for (sg = sgs[n]; sg; sg = next(sg, &total_in)) {
259 vq->vring.desc[i].flags = VRING_DESC_F_NEXT|VRING_DESC_F_WRITE;
260 vq->vring.desc[i].addr = sg_phys(sg);
261 vq->vring.desc[i].len = sg->length;
262 prev = i;
263 i = vq->vring.desc[i].next;
264 }
265 }
266
267 vq->vring.desc[prev].flags &= ~VRING_DESC_F_NEXT;
268
269
270 vq->free_head = i;
271
272add_head:
273
274 vq->data[head] = data;
275
276
277
278 avail = (vq->vring.avail->idx & (vq->vring.num-1));
279 vq->vring.avail->ring[avail] = head;
280
281
282
283 virtio_wmb(vq->weak_barriers);
284 vq->vring.avail->idx++;
285 vq->num_added++;
286
287
288
289 if (unlikely(vq->num_added == (1 << 16) - 1))
290 virtqueue_kick(_vq);
291
292 pr_debug("Added buffer head %i to %p\n", head, vq);
293 END_USE(vq);
294
295 return 0;
296}
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311
312int virtqueue_add_buf(struct virtqueue *_vq,
313 struct scatterlist sg[],
314 unsigned int out,
315 unsigned int in,
316 void *data,
317 gfp_t gfp)
318{
319 struct scatterlist *sgs[2];
320
321 sgs[0] = sg;
322 sgs[1] = sg + out;
323
324 return virtqueue_add(_vq, sgs, sg_next_arr,
325 out, in, out ? 1 : 0, in ? 1 : 0, data, gfp);
326}
327EXPORT_SYMBOL_GPL(virtqueue_add_buf);
328
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341
342
343int virtqueue_add_sgs(struct virtqueue *_vq,
344 struct scatterlist *sgs[],
345 unsigned int out_sgs,
346 unsigned int in_sgs,
347 void *data,
348 gfp_t gfp)
349{
350 unsigned int i, total_out, total_in;
351
352
353 for (i = total_out = total_in = 0; i < out_sgs; i++) {
354 struct scatterlist *sg;
355 for (sg = sgs[i]; sg; sg = sg_next(sg))
356 total_out++;
357 }
358 for (; i < out_sgs + in_sgs; i++) {
359 struct scatterlist *sg;
360 for (sg = sgs[i]; sg; sg = sg_next(sg))
361 total_in++;
362 }
363 return virtqueue_add(_vq, sgs, sg_next_chained,
364 total_out, total_in, out_sgs, in_sgs, data, gfp);
365}
366EXPORT_SYMBOL_GPL(virtqueue_add_sgs);
367
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379
380
381int virtqueue_add_outbuf(struct virtqueue *vq,
382 struct scatterlist sg[], unsigned int num,
383 void *data,
384 gfp_t gfp)
385{
386 return virtqueue_add(vq, &sg, sg_next_arr, num, 0, 1, 0, data, gfp);
387}
388EXPORT_SYMBOL_GPL(virtqueue_add_outbuf);
389
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401
402
403int virtqueue_add_inbuf(struct virtqueue *vq,
404 struct scatterlist sg[], unsigned int num,
405 void *data,
406 gfp_t gfp)
407{
408 return virtqueue_add(vq, &sg, sg_next_arr, 0, num, 0, 1, data, gfp);
409}
410EXPORT_SYMBOL_GPL(virtqueue_add_inbuf);
411
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421
422
423bool virtqueue_kick_prepare(struct virtqueue *_vq)
424{
425 struct vring_virtqueue *vq = to_vvq(_vq);
426 u16 new, old;
427 bool needs_kick;
428
429 START_USE(vq);
430
431
432 virtio_mb(vq->weak_barriers);
433
434 old = vq->vring.avail->idx - vq->num_added;
435 new = vq->vring.avail->idx;
436 vq->num_added = 0;
437
438#ifdef DEBUG
439 if (vq->last_add_time_valid) {
440 WARN_ON(ktime_to_ms(ktime_sub(ktime_get(),
441 vq->last_add_time)) > 100);
442 }
443 vq->last_add_time_valid = false;
444#endif
445
446 if (vq->event) {
447 needs_kick = vring_need_event(vring_avail_event(&vq->vring),
448 new, old);
449 } else {
450 needs_kick = !(vq->vring.used->flags & VRING_USED_F_NO_NOTIFY);
451 }
452 END_USE(vq);
453 return needs_kick;
454}
455EXPORT_SYMBOL_GPL(virtqueue_kick_prepare);
456
457
458
459
460
461
462
463void virtqueue_notify(struct virtqueue *_vq)
464{
465 struct vring_virtqueue *vq = to_vvq(_vq);
466
467
468 vq->notify(_vq);
469}
470EXPORT_SYMBOL_GPL(virtqueue_notify);
471
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481
482void virtqueue_kick(struct virtqueue *vq)
483{
484 if (virtqueue_kick_prepare(vq))
485 virtqueue_notify(vq);
486}
487EXPORT_SYMBOL_GPL(virtqueue_kick);
488
489static void detach_buf(struct vring_virtqueue *vq, unsigned int head)
490{
491 unsigned int i;
492
493
494 vq->data[head] = NULL;
495
496
497 i = head;
498
499
500 if (vq->vring.desc[i].flags & VRING_DESC_F_INDIRECT)
501 kfree(phys_to_virt(vq->vring.desc[i].addr));
502
503 while (vq->vring.desc[i].flags & VRING_DESC_F_NEXT) {
504 i = vq->vring.desc[i].next;
505 vq->vq.num_free++;
506 }
507
508 vq->vring.desc[i].next = vq->free_head;
509 vq->free_head = head;
510
511 vq->vq.num_free++;
512}
513
514static inline bool more_used(const struct vring_virtqueue *vq)
515{
516 return vq->last_used_idx != vq->vring.used->idx;
517}
518
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535void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len)
536{
537 struct vring_virtqueue *vq = to_vvq(_vq);
538 void *ret;
539 unsigned int i;
540 u16 last_used;
541
542 START_USE(vq);
543
544 if (unlikely(vq->broken)) {
545 END_USE(vq);
546 return NULL;
547 }
548
549 if (!more_used(vq)) {
550 pr_debug("No more buffers in queue\n");
551 END_USE(vq);
552 return NULL;
553 }
554
555
556 virtio_rmb(vq->weak_barriers);
557
558 last_used = (vq->last_used_idx & (vq->vring.num - 1));
559 i = vq->vring.used->ring[last_used].id;
560 *len = vq->vring.used->ring[last_used].len;
561
562 if (unlikely(i >= vq->vring.num)) {
563 BAD_RING(vq, "id %u out of range\n", i);
564 return NULL;
565 }
566 if (unlikely(!vq->data[i])) {
567 BAD_RING(vq, "id %u is not a head!\n", i);
568 return NULL;
569 }
570
571
572 ret = vq->data[i];
573 detach_buf(vq, i);
574 vq->last_used_idx++;
575
576
577
578 if (!(vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)) {
579 vring_used_event(&vq->vring) = vq->last_used_idx;
580 virtio_mb(vq->weak_barriers);
581 }
582
583#ifdef DEBUG
584 vq->last_add_time_valid = false;
585#endif
586
587 END_USE(vq);
588 return ret;
589}
590EXPORT_SYMBOL_GPL(virtqueue_get_buf);
591
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599
600
601void virtqueue_disable_cb(struct virtqueue *_vq)
602{
603 struct vring_virtqueue *vq = to_vvq(_vq);
604
605 vq->vring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
606}
607EXPORT_SYMBOL_GPL(virtqueue_disable_cb);
608
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619
620bool virtqueue_enable_cb(struct virtqueue *_vq)
621{
622 struct vring_virtqueue *vq = to_vvq(_vq);
623
624 START_USE(vq);
625
626
627
628
629
630
631 vq->vring.avail->flags &= ~VRING_AVAIL_F_NO_INTERRUPT;
632 vring_used_event(&vq->vring) = vq->last_used_idx;
633 virtio_mb(vq->weak_barriers);
634 if (unlikely(more_used(vq))) {
635 END_USE(vq);
636 return false;
637 }
638
639 END_USE(vq);
640 return true;
641}
642EXPORT_SYMBOL_GPL(virtqueue_enable_cb);
643
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655
656
657bool virtqueue_enable_cb_delayed(struct virtqueue *_vq)
658{
659 struct vring_virtqueue *vq = to_vvq(_vq);
660 u16 bufs;
661
662 START_USE(vq);
663
664
665
666
667
668
669 vq->vring.avail->flags &= ~VRING_AVAIL_F_NO_INTERRUPT;
670
671 bufs = (u16)(vq->vring.avail->idx - vq->last_used_idx) * 3 / 4;
672 vring_used_event(&vq->vring) = vq->last_used_idx + bufs;
673 virtio_mb(vq->weak_barriers);
674 if (unlikely((u16)(vq->vring.used->idx - vq->last_used_idx) > bufs)) {
675 END_USE(vq);
676 return false;
677 }
678
679 END_USE(vq);
680 return true;
681}
682EXPORT_SYMBOL_GPL(virtqueue_enable_cb_delayed);
683
684
685
686
687
688
689
690
691
692void *virtqueue_detach_unused_buf(struct virtqueue *_vq)
693{
694 struct vring_virtqueue *vq = to_vvq(_vq);
695 unsigned int i;
696 void *buf;
697
698 START_USE(vq);
699
700 for (i = 0; i < vq->vring.num; i++) {
701 if (!vq->data[i])
702 continue;
703
704 buf = vq->data[i];
705 detach_buf(vq, i);
706 vq->vring.avail->idx--;
707 END_USE(vq);
708 return buf;
709 }
710
711 BUG_ON(vq->vq.num_free != vq->vring.num);
712
713 END_USE(vq);
714 return NULL;
715}
716EXPORT_SYMBOL_GPL(virtqueue_detach_unused_buf);
717
718irqreturn_t vring_interrupt(int irq, void *_vq)
719{
720 struct vring_virtqueue *vq = to_vvq(_vq);
721
722 if (!more_used(vq)) {
723 pr_debug("virtqueue interrupt with no work for %p\n", vq);
724 return IRQ_NONE;
725 }
726
727 if (unlikely(vq->broken))
728 return IRQ_HANDLED;
729
730 pr_debug("virtqueue callback for %p (%p)\n", vq, vq->vq.callback);
731 if (vq->vq.callback)
732 vq->vq.callback(&vq->vq);
733
734 return IRQ_HANDLED;
735}
736EXPORT_SYMBOL_GPL(vring_interrupt);
737
738struct virtqueue *vring_new_virtqueue(unsigned int index,
739 unsigned int num,
740 unsigned int vring_align,
741 struct virtio_device *vdev,
742 bool weak_barriers,
743 void *pages,
744 void (*notify)(struct virtqueue *),
745 void (*callback)(struct virtqueue *),
746 const char *name)
747{
748 struct vring_virtqueue *vq;
749 unsigned int i;
750
751
752 if (num & (num - 1)) {
753 dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num);
754 return NULL;
755 }
756
757 vq = kmalloc(sizeof(*vq) + sizeof(void *)*num, GFP_KERNEL);
758 if (!vq)
759 return NULL;
760
761 vring_init(&vq->vring, num, pages, vring_align);
762 vq->vq.callback = callback;
763 vq->vq.vdev = vdev;
764 vq->vq.name = name;
765 vq->vq.num_free = num;
766 vq->vq.index = index;
767 vq->notify = notify;
768 vq->weak_barriers = weak_barriers;
769 vq->broken = false;
770 vq->last_used_idx = 0;
771 vq->num_added = 0;
772 list_add_tail(&vq->vq.list, &vdev->vqs);
773#ifdef DEBUG
774 vq->in_use = false;
775 vq->last_add_time_valid = false;
776#endif
777
778 vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC);
779 vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
780
781
782 if (!callback)
783 vq->vring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
784
785
786 vq->free_head = 0;
787 for (i = 0; i < num-1; i++) {
788 vq->vring.desc[i].next = i+1;
789 vq->data[i] = NULL;
790 }
791 vq->data[i] = NULL;
792
793 return &vq->vq;
794}
795EXPORT_SYMBOL_GPL(vring_new_virtqueue);
796
797void vring_del_virtqueue(struct virtqueue *vq)
798{
799 list_del(&vq->list);
800 kfree(to_vvq(vq));
801}
802EXPORT_SYMBOL_GPL(vring_del_virtqueue);
803
804
805void vring_transport_features(struct virtio_device *vdev)
806{
807 unsigned int i;
808
809 for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) {
810 switch (i) {
811 case VIRTIO_RING_F_INDIRECT_DESC:
812 break;
813 case VIRTIO_RING_F_EVENT_IDX:
814 break;
815 default:
816
817 clear_bit(i, vdev->features);
818 }
819 }
820}
821EXPORT_SYMBOL_GPL(vring_transport_features);
822
823
824
825
826
827
828
829
830unsigned int virtqueue_get_vring_size(struct virtqueue *_vq)
831{
832
833 struct vring_virtqueue *vq = to_vvq(_vq);
834
835 return vq->vring.num;
836}
837EXPORT_SYMBOL_GPL(virtqueue_get_vring_size);
838
839MODULE_LICENSE("GPL");
840