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iommu/arm-smmu-v3: Separate s/w and h/w views of prod and cons indexes
[linux/fpc-iii.git] / drivers / vhost / vhost.c
blob0536f85263599722b45fd9eaeb05da88085ea9c1
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (C) 2009 Red Hat, Inc.
3 * Copyright (C) 2006 Rusty Russell IBM Corporation
4 *
5 * Author: Michael S. Tsirkin <mst@redhat.com>
6 *
7 * Inspiration, some code, and most witty comments come from
8 * Documentation/virtual/lguest/lguest.c, by Rusty Russell
9 *
10 * Generic code for virtio server in host kernel.
11 */
12
13 #include <linux/eventfd.h>
14 #include <linux/vhost.h>
15 #include <linux/uio.h>
16 #include <linux/mm.h>
17 #include <linux/mmu_context.h>
18 #include <linux/miscdevice.h>
19 #include <linux/mutex.h>
20 #include <linux/poll.h>
21 #include <linux/file.h>
22 #include <linux/highmem.h>
23 #include <linux/slab.h>
24 #include <linux/vmalloc.h>
25 #include <linux/kthread.h>
26 #include <linux/cgroup.h>
27 #include <linux/module.h>
28 #include <linux/sort.h>
29 #include <linux/sched/mm.h>
30 #include <linux/sched/signal.h>
31 #include <linux/interval_tree_generic.h>
32 #include <linux/nospec.h>
33
34 #include "vhost.h"
35
36 static ushort max_mem_regions = 64;
37 module_param(max_mem_regions, ushort, 0444);
38 MODULE_PARM_DESC(max_mem_regions,
39 "Maximum number of memory regions in memory map. (default: 64)");
40 static int max_iotlb_entries = 2048;
41 module_param(max_iotlb_entries, int, 0444);
42 MODULE_PARM_DESC(max_iotlb_entries,
43 "Maximum number of iotlb entries. (default: 2048)");
44
45 enum {
46 VHOST_MEMORY_F_LOG = 0x1,
47 };
48
49 #define vhost_used_event(vq) ((__virtio16 __user *)&vq->avail->ring[vq->num])
50 #define vhost_avail_event(vq) ((__virtio16 __user *)&vq->used->ring[vq->num])
51
52 INTERVAL_TREE_DEFINE(struct vhost_umem_node,
53 rb, __u64, __subtree_last,
54 START, LAST, static inline, vhost_umem_interval_tree);
55
56 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
57 static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
58 {
59 vq->user_be = !virtio_legacy_is_little_endian();
60 }
61
62 static void vhost_enable_cross_endian_big(struct vhost_virtqueue *vq)
63 {
64 vq->user_be = true;
65 }
66
67 static void vhost_enable_cross_endian_little(struct vhost_virtqueue *vq)
68 {
69 vq->user_be = false;
70 }
71
72 static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
73 {
74 struct vhost_vring_state s;
75
76 if (vq->private_data)
77 return -EBUSY;
78
79 if (copy_from_user(&s, argp, sizeof(s)))
80 return -EFAULT;
81
82 if (s.num != VHOST_VRING_LITTLE_ENDIAN &&
83 s.num != VHOST_VRING_BIG_ENDIAN)
84 return -EINVAL;
85
86 if (s.num == VHOST_VRING_BIG_ENDIAN)
87 vhost_enable_cross_endian_big(vq);
88 else
89 vhost_enable_cross_endian_little(vq);
90
91 return 0;
92 }
93
94 static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
95 int __user *argp)
96 {
97 struct vhost_vring_state s = {
98 .index = idx,
99 .num = vq->user_be
100 };
101
102 if (copy_to_user(argp, &s, sizeof(s)))
103 return -EFAULT;
104
105 return 0;
106 }
107
108 static void vhost_init_is_le(struct vhost_virtqueue *vq)
109 {
110 /* Note for legacy virtio: user_be is initialized at reset time
111 * according to the host endianness. If userspace does not set an
112 * explicit endianness, the default behavior is native endian, as
113 * expected by legacy virtio.
114 */
115 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1) || !vq->user_be;
116 }
117 #else
118 static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
119 {
120 }
121
122 static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
123 {
124 return -ENOIOCTLCMD;
125 }
126
127 static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
128 int __user *argp)
129 {
130 return -ENOIOCTLCMD;
131 }
132
133 static void vhost_init_is_le(struct vhost_virtqueue *vq)
134 {
135 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1)
136 || virtio_legacy_is_little_endian();
137 }
138 #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
139
140 static void vhost_reset_is_le(struct vhost_virtqueue *vq)
141 {
142 vhost_init_is_le(vq);
143 }
144
145 struct vhost_flush_struct {
146 struct vhost_work work;
147 struct completion wait_event;
148 };
149
150 static void vhost_flush_work(struct vhost_work *work)
151 {
152 struct vhost_flush_struct *s;
153
154 s = container_of(work, struct vhost_flush_struct, work);
155 complete(&s->wait_event);
156 }
157
158 static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
159 poll_table *pt)
160 {
161 struct vhost_poll *poll;
162
163 poll = container_of(pt, struct vhost_poll, table);
164 poll->wqh = wqh;
165 add_wait_queue(wqh, &poll->wait);
166 }
167
168 static int vhost_poll_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync,
169 void *key)
170 {
171 struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait);
172
173 if (!(key_to_poll(key) & poll->mask))
174 return 0;
175
176 vhost_poll_queue(poll);
177 return 0;
178 }
179
180 void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn)
181 {
182 clear_bit(VHOST_WORK_QUEUED, &work->flags);
183 work->fn = fn;
184 }
185 EXPORT_SYMBOL_GPL(vhost_work_init);
186
187 /* Init poll structure */
188 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
189 __poll_t mask, struct vhost_dev *dev)
190 {
191 init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup);
192 init_poll_funcptr(&poll->table, vhost_poll_func);
193 poll->mask = mask;
194 poll->dev = dev;
195 poll->wqh = NULL;
196
197 vhost_work_init(&poll->work, fn);
198 }
199 EXPORT_SYMBOL_GPL(vhost_poll_init);
200
201 /* Start polling a file. We add ourselves to file's wait queue. The caller must
202 * keep a reference to a file until after vhost_poll_stop is called. */
203 int vhost_poll_start(struct vhost_poll *poll, struct file *file)
204 {
205 __poll_t mask;
206 int ret = 0;
207
208 if (poll->wqh)
209 return 0;
210
211 mask = vfs_poll(file, &poll->table);
212 if (mask)
213 vhost_poll_wakeup(&poll->wait, 0, 0, poll_to_key(mask));
214 if (mask & EPOLLERR) {
215 vhost_poll_stop(poll);
216 ret = -EINVAL;
217 }
218
219 return ret;
220 }
221 EXPORT_SYMBOL_GPL(vhost_poll_start);
222
223 /* Stop polling a file. After this function returns, it becomes safe to drop the
224 * file reference. You must also flush afterwards. */
225 void vhost_poll_stop(struct vhost_poll *poll)
226 {
227 if (poll->wqh) {
228 remove_wait_queue(poll->wqh, &poll->wait);
229 poll->wqh = NULL;
230 }
231 }
232 EXPORT_SYMBOL_GPL(vhost_poll_stop);
233
234 void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work)
235 {
236 struct vhost_flush_struct flush;
237
238 if (dev->worker) {
239 init_completion(&flush.wait_event);
240 vhost_work_init(&flush.work, vhost_flush_work);
241
242 vhost_work_queue(dev, &flush.work);
243 wait_for_completion(&flush.wait_event);
244 }
245 }
246 EXPORT_SYMBOL_GPL(vhost_work_flush);
247
248 /* Flush any work that has been scheduled. When calling this, don't hold any
249 * locks that are also used by the callback. */
250 void vhost_poll_flush(struct vhost_poll *poll)
251 {
252 vhost_work_flush(poll->dev, &poll->work);
253 }
254 EXPORT_SYMBOL_GPL(vhost_poll_flush);
255
256 void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work)
257 {
258 if (!dev->worker)
259 return;
260
261 if (!test_and_set_bit(VHOST_WORK_QUEUED, &work->flags)) {
262 /* We can only add the work to the list after we're
263 * sure it was not in the list.
264 * test_and_set_bit() implies a memory barrier.
265 */
266 llist_add(&work->node, &dev->work_list);
267 wake_up_process(dev->worker);
268 }
269 }
270 EXPORT_SYMBOL_GPL(vhost_work_queue);
271
272 /* A lockless hint for busy polling code to exit the loop */
273 bool vhost_has_work(struct vhost_dev *dev)
274 {
275 return !llist_empty(&dev->work_list);
276 }
277 EXPORT_SYMBOL_GPL(vhost_has_work);
278
279 void vhost_poll_queue(struct vhost_poll *poll)
280 {
281 vhost_work_queue(poll->dev, &poll->work);
282 }
283 EXPORT_SYMBOL_GPL(vhost_poll_queue);
284
285 static void __vhost_vq_meta_reset(struct vhost_virtqueue *vq)
286 {
287 int j;
288
289 for (j = 0; j < VHOST_NUM_ADDRS; j++)
290 vq->meta_iotlb[j] = NULL;
291 }
292
293 static void vhost_vq_meta_reset(struct vhost_dev *d)
294 {
295 int i;
296
297 for (i = 0; i < d->nvqs; ++i)
298 __vhost_vq_meta_reset(d->vqs[i]);
299 }
300
301 #if VHOST_ARCH_CAN_ACCEL_UACCESS
302 static void vhost_map_unprefetch(struct vhost_map *map)
303 {
304 kfree(map->pages);
305 map->pages = NULL;
306 map->npages = 0;
307 map->addr = NULL;
308 }
309
310 static void vhost_uninit_vq_maps(struct vhost_virtqueue *vq)
311 {
312 struct vhost_map *map[VHOST_NUM_ADDRS];
313 int i;
314
315 spin_lock(&vq->mmu_lock);
316 for (i = 0; i < VHOST_NUM_ADDRS; i++) {
317 map[i] = rcu_dereference_protected(vq->maps[i],
318 lockdep_is_held(&vq->mmu_lock));
319 if (map[i])
320 rcu_assign_pointer(vq->maps[i], NULL);
321 }
322 spin_unlock(&vq->mmu_lock);
323
324 synchronize_rcu();
325
326 for (i = 0; i < VHOST_NUM_ADDRS; i++)
327 if (map[i])
328 vhost_map_unprefetch(map[i]);
329
330 }
331
332 static void vhost_reset_vq_maps(struct vhost_virtqueue *vq)
333 {
334 int i;
335
336 vhost_uninit_vq_maps(vq);
337 for (i = 0; i < VHOST_NUM_ADDRS; i++)
338 vq->uaddrs[i].size = 0;
339 }
340
341 static bool vhost_map_range_overlap(struct vhost_uaddr *uaddr,
342 unsigned long start,
343 unsigned long end)
344 {
345 if (unlikely(!uaddr->size))
346 return false;
347
348 return !(end < uaddr->uaddr || start > uaddr->uaddr - 1 + uaddr->size);
349 }
350
351 static void vhost_invalidate_vq_start(struct vhost_virtqueue *vq,
352 int index,
353 unsigned long start,
354 unsigned long end)
355 {
356 struct vhost_uaddr *uaddr = &vq->uaddrs[index];
357 struct vhost_map *map;
358 int i;
359
360 if (!vhost_map_range_overlap(uaddr, start, end))
361 return;
362
363 spin_lock(&vq->mmu_lock);
364 ++vq->invalidate_count;
365
366 map = rcu_dereference_protected(vq->maps[index],
367 lockdep_is_held(&vq->mmu_lock));
368 if (map) {
369 if (uaddr->write) {
370 for (i = 0; i < map->npages; i++)
371 set_page_dirty(map->pages[i]);
372 }
373 rcu_assign_pointer(vq->maps[index], NULL);
374 }
375 spin_unlock(&vq->mmu_lock);
376
377 if (map) {
378 synchronize_rcu();
379 vhost_map_unprefetch(map);
380 }
381 }
382
383 static void vhost_invalidate_vq_end(struct vhost_virtqueue *vq,
384 int index,
385 unsigned long start,
386 unsigned long end)
387 {
388 if (!vhost_map_range_overlap(&vq->uaddrs[index], start, end))
389 return;
390
391 spin_lock(&vq->mmu_lock);
392 --vq->invalidate_count;
393 spin_unlock(&vq->mmu_lock);
394 }
395
396 static int vhost_invalidate_range_start(struct mmu_notifier *mn,
397 const struct mmu_notifier_range *range)
398 {
399 struct vhost_dev *dev = container_of(mn, struct vhost_dev,
400 mmu_notifier);
401 int i, j;
402
403 if (!mmu_notifier_range_blockable(range))
404 return -EAGAIN;
405
406 for (i = 0; i < dev->nvqs; i++) {
407 struct vhost_virtqueue *vq = dev->vqs[i];
408
409 for (j = 0; j < VHOST_NUM_ADDRS; j++)
410 vhost_invalidate_vq_start(vq, j,
411 range->start,
412 range->end);
413 }
414
415 return 0;
416 }
417
418 static void vhost_invalidate_range_end(struct mmu_notifier *mn,
419 const struct mmu_notifier_range *range)
420 {
421 struct vhost_dev *dev = container_of(mn, struct vhost_dev,
422 mmu_notifier);
423 int i, j;
424
425 for (i = 0; i < dev->nvqs; i++) {
426 struct vhost_virtqueue *vq = dev->vqs[i];
427
428 for (j = 0; j < VHOST_NUM_ADDRS; j++)
429 vhost_invalidate_vq_end(vq, j,
430 range->start,
431 range->end);
432 }
433 }
434
435 static const struct mmu_notifier_ops vhost_mmu_notifier_ops = {
436 .invalidate_range_start = vhost_invalidate_range_start,
437 .invalidate_range_end = vhost_invalidate_range_end,
438 };
439
440 static void vhost_init_maps(struct vhost_dev *dev)
441 {
442 struct vhost_virtqueue *vq;
443 int i, j;
444
445 dev->mmu_notifier.ops = &vhost_mmu_notifier_ops;
446
447 for (i = 0; i < dev->nvqs; ++i) {
448 vq = dev->vqs[i];
449 for (j = 0; j < VHOST_NUM_ADDRS; j++)
450 RCU_INIT_POINTER(vq->maps[j], NULL);
451 }
452 }
453 #endif
454
455 static void vhost_vq_reset(struct vhost_dev *dev,
456 struct vhost_virtqueue *vq)
457 {
458 vq->num = 1;
459 vq->desc = NULL;
460 vq->avail = NULL;
461 vq->used = NULL;
462 vq->last_avail_idx = 0;
463 vq->avail_idx = 0;
464 vq->last_used_idx = 0;
465 vq->signalled_used = 0;
466 vq->signalled_used_valid = false;
467 vq->used_flags = 0;
468 vq->log_used = false;
469 vq->log_addr = -1ull;
470 vq->private_data = NULL;
471 vq->acked_features = 0;
472 vq->acked_backend_features = 0;
473 vq->log_base = NULL;
474 vq->error_ctx = NULL;
475 vq->kick = NULL;
476 vq->call_ctx = NULL;
477 vq->log_ctx = NULL;
478 vhost_reset_is_le(vq);
479 vhost_disable_cross_endian(vq);
480 vq->busyloop_timeout = 0;
481 vq->umem = NULL;
482 vq->iotlb = NULL;
483 vq->invalidate_count = 0;
484 __vhost_vq_meta_reset(vq);
485 #if VHOST_ARCH_CAN_ACCEL_UACCESS
486 vhost_reset_vq_maps(vq);
487 #endif
488 }
489
490 static int vhost_worker(void *data)
491 {
492 struct vhost_dev *dev = data;
493 struct vhost_work *work, *work_next;
494 struct llist_node *node;
495 mm_segment_t oldfs = get_fs();
496
497 set_fs(USER_DS);
498 use_mm(dev->mm);
499
500 for (;;) {
501 /* mb paired w/ kthread_stop */
502 set_current_state(TASK_INTERRUPTIBLE);
503
504 if (kthread_should_stop()) {
505 __set_current_state(TASK_RUNNING);
506 break;
507 }
508
509 node = llist_del_all(&dev->work_list);
510 if (!node)
511 schedule();
512
513 node = llist_reverse_order(node);
514 /* make sure flag is seen after deletion */
515 smp_wmb();
516 llist_for_each_entry_safe(work, work_next, node, node) {
517 clear_bit(VHOST_WORK_QUEUED, &work->flags);
518 __set_current_state(TASK_RUNNING);
519 work->fn(work);
520 if (need_resched())
521 schedule();
522 }
523 }
524 unuse_mm(dev->mm);
525 set_fs(oldfs);
526 return 0;
527 }
528
529 static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq)
530 {
531 kfree(vq->indirect);
532 vq->indirect = NULL;
533 kfree(vq->log);
534 vq->log = NULL;
535 kfree(vq->heads);
536 vq->heads = NULL;
537 }
538
539 /* Helper to allocate iovec buffers for all vqs. */
540 static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
541 {
542 struct vhost_virtqueue *vq;
543 int i;
544
545 for (i = 0; i < dev->nvqs; ++i) {
546 vq = dev->vqs[i];
547 vq->indirect = kmalloc_array(UIO_MAXIOV,
548 sizeof(*vq->indirect),
549 GFP_KERNEL);
550 vq->log = kmalloc_array(dev->iov_limit, sizeof(*vq->log),
551 GFP_KERNEL);
552 vq->heads = kmalloc_array(dev->iov_limit, sizeof(*vq->heads),
553 GFP_KERNEL);
554 if (!vq->indirect || !vq->log || !vq->heads)
555 goto err_nomem;
556 }
557 return 0;
558
559 err_nomem:
560 for (; i >= 0; --i)
561 vhost_vq_free_iovecs(dev->vqs[i]);
562 return -ENOMEM;
563 }
564
565 static void vhost_dev_free_iovecs(struct vhost_dev *dev)
566 {
567 int i;
568
569 for (i = 0; i < dev->nvqs; ++i)
570 vhost_vq_free_iovecs(dev->vqs[i]);
571 }
572
573 bool vhost_exceeds_weight(struct vhost_virtqueue *vq,
574 int pkts, int total_len)
575 {
576 struct vhost_dev *dev = vq->dev;
577
578 if ((dev->byte_weight && total_len >= dev->byte_weight) ||
579 pkts >= dev->weight) {
580 vhost_poll_queue(&vq->poll);
581 return true;
582 }
583
584 return false;
585 }
586 EXPORT_SYMBOL_GPL(vhost_exceeds_weight);
587
588 static size_t vhost_get_avail_size(struct vhost_virtqueue *vq,
589 unsigned int num)
590 {
591 size_t event __maybe_unused =
592 vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
593
594 return sizeof(*vq->avail) +
595 sizeof(*vq->avail->ring) * num + event;
596 }
597
598 static size_t vhost_get_used_size(struct vhost_virtqueue *vq,
599 unsigned int num)
600 {
601 size_t event __maybe_unused =
602 vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
603
604 return sizeof(*vq->used) +
605 sizeof(*vq->used->ring) * num + event;
606 }
607
608 static size_t vhost_get_desc_size(struct vhost_virtqueue *vq,
609 unsigned int num)
610 {
611 return sizeof(*vq->desc) * num;
612 }
613
614 void vhost_dev_init(struct vhost_dev *dev,
615 struct vhost_virtqueue **vqs, int nvqs,
616 int iov_limit, int weight, int byte_weight)
617 {
618 struct vhost_virtqueue *vq;
619 int i;
620
621 dev->vqs = vqs;
622 dev->nvqs = nvqs;
623 mutex_init(&dev->mutex);
624 dev->log_ctx = NULL;
625 dev->umem = NULL;
626 dev->iotlb = NULL;
627 dev->mm = NULL;
628 dev->worker = NULL;
629 dev->iov_limit = iov_limit;
630 dev->weight = weight;
631 dev->byte_weight = byte_weight;
632 init_llist_head(&dev->work_list);
633 init_waitqueue_head(&dev->wait);
634 INIT_LIST_HEAD(&dev->read_list);
635 INIT_LIST_HEAD(&dev->pending_list);
636 spin_lock_init(&dev->iotlb_lock);
637 #if VHOST_ARCH_CAN_ACCEL_UACCESS
638 vhost_init_maps(dev);
639 #endif
640
641 for (i = 0; i < dev->nvqs; ++i) {
642 vq = dev->vqs[i];
643 vq->log = NULL;
644 vq->indirect = NULL;
645 vq->heads = NULL;
646 vq->dev = dev;
647 mutex_init(&vq->mutex);
648 spin_lock_init(&vq->mmu_lock);
649 vhost_vq_reset(dev, vq);
650 if (vq->handle_kick)
651 vhost_poll_init(&vq->poll, vq->handle_kick,
652 EPOLLIN, dev);
653 }
654 }
655 EXPORT_SYMBOL_GPL(vhost_dev_init);
656
657 /* Caller should have device mutex */
658 long vhost_dev_check_owner(struct vhost_dev *dev)
659 {
660 /* Are you the owner? If not, I don't think you mean to do that */
661 return dev->mm == current->mm ? 0 : -EPERM;
662 }
663 EXPORT_SYMBOL_GPL(vhost_dev_check_owner);
664
665 struct vhost_attach_cgroups_struct {
666 struct vhost_work work;
667 struct task_struct *owner;
668 int ret;
669 };
670
671 static void vhost_attach_cgroups_work(struct vhost_work *work)
672 {
673 struct vhost_attach_cgroups_struct *s;
674
675 s = container_of(work, struct vhost_attach_cgroups_struct, work);
676 s->ret = cgroup_attach_task_all(s->owner, current);
677 }
678
679 static int vhost_attach_cgroups(struct vhost_dev *dev)
680 {
681 struct vhost_attach_cgroups_struct attach;
682
683 attach.owner = current;
684 vhost_work_init(&attach.work, vhost_attach_cgroups_work);
685 vhost_work_queue(dev, &attach.work);
686 vhost_work_flush(dev, &attach.work);
687 return attach.ret;
688 }
689
690 /* Caller should have device mutex */
691 bool vhost_dev_has_owner(struct vhost_dev *dev)
692 {
693 return dev->mm;
694 }
695 EXPORT_SYMBOL_GPL(vhost_dev_has_owner);
696
697 /* Caller should have device mutex */
698 long vhost_dev_set_owner(struct vhost_dev *dev)
699 {
700 struct task_struct *worker;
701 int err;
702
703 /* Is there an owner already? */
704 if (vhost_dev_has_owner(dev)) {
705 err = -EBUSY;
706 goto err_mm;
707 }
708
709 /* No owner, become one */
710 dev->mm = get_task_mm(current);
711 worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid);
712 if (IS_ERR(worker)) {
713 err = PTR_ERR(worker);
714 goto err_worker;
715 }
716
717 dev->worker = worker;
718 wake_up_process(worker); /* avoid contributing to loadavg */
719
720 err = vhost_attach_cgroups(dev);
721 if (err)
722 goto err_cgroup;
723
724 err = vhost_dev_alloc_iovecs(dev);
725 if (err)
726 goto err_cgroup;
727
728 #if VHOST_ARCH_CAN_ACCEL_UACCESS
729 err = mmu_notifier_register(&dev->mmu_notifier, dev->mm);
730 if (err)
731 goto err_mmu_notifier;
732 #endif
733
734 return 0;
735
736 #if VHOST_ARCH_CAN_ACCEL_UACCESS
737 err_mmu_notifier:
738 vhost_dev_free_iovecs(dev);
739 #endif
740 err_cgroup:
741 kthread_stop(worker);
742 dev->worker = NULL;
743 err_worker:
744 if (dev->mm)
745 mmput(dev->mm);
746 dev->mm = NULL;
747 err_mm:
748 return err;
749 }
750 EXPORT_SYMBOL_GPL(vhost_dev_set_owner);
751
752 struct vhost_umem *vhost_dev_reset_owner_prepare(void)
753 {
754 return kvzalloc(sizeof(struct vhost_umem), GFP_KERNEL);
755 }
756 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare);
757
758 /* Caller should have device mutex */
759 void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_umem *umem)
760 {
761 int i;
762
763 vhost_dev_cleanup(dev);
764
765 /* Restore memory to default empty mapping. */
766 INIT_LIST_HEAD(&umem->umem_list);
767 dev->umem = umem;
768 /* We don't need VQ locks below since vhost_dev_cleanup makes sure
769 * VQs aren't running.
770 */
771 for (i = 0; i < dev->nvqs; ++i)
772 dev->vqs[i]->umem = umem;
773 }
774 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner);
775
776 void vhost_dev_stop(struct vhost_dev *dev)
777 {
778 int i;
779
780 for (i = 0; i < dev->nvqs; ++i) {
781 if (dev->vqs[i]->kick && dev->vqs[i]->handle_kick) {
782 vhost_poll_stop(&dev->vqs[i]->poll);
783 vhost_poll_flush(&dev->vqs[i]->poll);
784 }
785 }
786 }
787 EXPORT_SYMBOL_GPL(vhost_dev_stop);
788
789 static void vhost_umem_free(struct vhost_umem *umem,
790 struct vhost_umem_node *node)
791 {
792 vhost_umem_interval_tree_remove(node, &umem->umem_tree);
793 list_del(&node->link);
794 kfree(node);
795 umem->numem--;
796 }
797
798 static void vhost_umem_clean(struct vhost_umem *umem)
799 {
800 struct vhost_umem_node *node, *tmp;
801
802 if (!umem)
803 return;
804
805 list_for_each_entry_safe(node, tmp, &umem->umem_list, link)
806 vhost_umem_free(umem, node);
807
808 kvfree(umem);
809 }
810
811 static void vhost_clear_msg(struct vhost_dev *dev)
812 {
813 struct vhost_msg_node *node, *n;
814
815 spin_lock(&dev->iotlb_lock);
816
817 list_for_each_entry_safe(node, n, &dev->read_list, node) {
818 list_del(&node->node);
819 kfree(node);
820 }
821
822 list_for_each_entry_safe(node, n, &dev->pending_list, node) {
823 list_del(&node->node);
824 kfree(node);
825 }
826
827 spin_unlock(&dev->iotlb_lock);
828 }
829
830 #if VHOST_ARCH_CAN_ACCEL_UACCESS
831 static void vhost_setup_uaddr(struct vhost_virtqueue *vq,
832 int index, unsigned long uaddr,
833 size_t size, bool write)
834 {
835 struct vhost_uaddr *addr = &vq->uaddrs[index];
836
837 addr->uaddr = uaddr;
838 addr->size = size;
839 addr->write = write;
840 }
841
842 static void vhost_setup_vq_uaddr(struct vhost_virtqueue *vq)
843 {
844 vhost_setup_uaddr(vq, VHOST_ADDR_DESC,
845 (unsigned long)vq->desc,
846 vhost_get_desc_size(vq, vq->num),
847 false);
848 vhost_setup_uaddr(vq, VHOST_ADDR_AVAIL,
849 (unsigned long)vq->avail,
850 vhost_get_avail_size(vq, vq->num),
851 false);
852 vhost_setup_uaddr(vq, VHOST_ADDR_USED,
853 (unsigned long)vq->used,
854 vhost_get_used_size(vq, vq->num),
855 true);
856 }
857
858 static int vhost_map_prefetch(struct vhost_virtqueue *vq,
859 int index)
860 {
861 struct vhost_map *map;
862 struct vhost_uaddr *uaddr = &vq->uaddrs[index];
863 struct page **pages;
864 int npages = DIV_ROUND_UP(uaddr->size, PAGE_SIZE);
865 int npinned;
866 void *vaddr, *v;
867 int err;
868 int i;
869
870 spin_lock(&vq->mmu_lock);
871
872 err = -EFAULT;
873 if (vq->invalidate_count)
874 goto err;
875
876 err = -ENOMEM;
877 map = kmalloc(sizeof(*map), GFP_ATOMIC);
878 if (!map)
879 goto err;
880
881 pages = kmalloc_array(npages, sizeof(struct page *), GFP_ATOMIC);
882 if (!pages)
883 goto err_pages;
884
885 err = EFAULT;
886 npinned = __get_user_pages_fast(uaddr->uaddr, npages,
887 uaddr->write, pages);
888 if (npinned > 0)
889 release_pages(pages, npinned);
890 if (npinned != npages)
891 goto err_gup;
892
893 for (i = 0; i < npinned; i++)
894 if (PageHighMem(pages[i]))
895 goto err_gup;
896
897 vaddr = v = page_address(pages[0]);
898
899 /* For simplicity, fallback to userspace address if VA is not
900 * contigious.
901 */
902 for (i = 1; i < npinned; i++) {
903 v += PAGE_SIZE;
904 if (v != page_address(pages[i]))
905 goto err_gup;
906 }
907
908 map->addr = vaddr + (uaddr->uaddr & (PAGE_SIZE - 1));
909 map->npages = npages;
910 map->pages = pages;
911
912 rcu_assign_pointer(vq->maps[index], map);
913 /* No need for a synchronize_rcu(). This function should be
914 * called by dev->worker so we are serialized with all
915 * readers.
916 */
917 spin_unlock(&vq->mmu_lock);
918
919 return 0;
920
921 err_gup:
922 kfree(pages);
923 err_pages:
924 kfree(map);
925 err:
926 spin_unlock(&vq->mmu_lock);
927 return err;
928 }
929 #endif
930
931 void vhost_dev_cleanup(struct vhost_dev *dev)
932 {
933 int i;
934
935 for (i = 0; i < dev->nvqs; ++i) {
936 if (dev->vqs[i]->error_ctx)
937 eventfd_ctx_put(dev->vqs[i]->error_ctx);
938 if (dev->vqs[i]->kick)
939 fput(dev->vqs[i]->kick);
940 if (dev->vqs[i]->call_ctx)
941 eventfd_ctx_put(dev->vqs[i]->call_ctx);
942 vhost_vq_reset(dev, dev->vqs[i]);
943 }
944 vhost_dev_free_iovecs(dev);
945 if (dev->log_ctx)
946 eventfd_ctx_put(dev->log_ctx);
947 dev->log_ctx = NULL;
948 /* No one will access memory at this point */
949 vhost_umem_clean(dev->umem);
950 dev->umem = NULL;
951 vhost_umem_clean(dev->iotlb);
952 dev->iotlb = NULL;
953 vhost_clear_msg(dev);
954 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
955 WARN_ON(!llist_empty(&dev->work_list));
956 if (dev->worker) {
957 kthread_stop(dev->worker);
958 dev->worker = NULL;
959 }
960 if (dev->mm) {
961 #if VHOST_ARCH_CAN_ACCEL_UACCESS
962 mmu_notifier_unregister(&dev->mmu_notifier, dev->mm);
963 #endif
964 mmput(dev->mm);
965 }
966 #if VHOST_ARCH_CAN_ACCEL_UACCESS
967 for (i = 0; i < dev->nvqs; i++)
968 vhost_uninit_vq_maps(dev->vqs[i]);
969 #endif
970 dev->mm = NULL;
971 }
972 EXPORT_SYMBOL_GPL(vhost_dev_cleanup);
973
974 static bool log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
975 {
976 u64 a = addr / VHOST_PAGE_SIZE / 8;
977
978 /* Make sure 64 bit math will not overflow. */
979 if (a > ULONG_MAX - (unsigned long)log_base ||
980 a + (unsigned long)log_base > ULONG_MAX)
981 return false;
982
983 return access_ok(log_base + a,
984 (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8);
985 }
986
987 static bool vhost_overflow(u64 uaddr, u64 size)
988 {
989 /* Make sure 64 bit math will not overflow. */
990 return uaddr > ULONG_MAX || size > ULONG_MAX || uaddr > ULONG_MAX - size;
991 }
992
993 /* Caller should have vq mutex and device mutex. */
994 static bool vq_memory_access_ok(void __user *log_base, struct vhost_umem *umem,
995 int log_all)
996 {
997 struct vhost_umem_node *node;
998
999 if (!umem)
1000 return false;
1001
1002 list_for_each_entry(node, &umem->umem_list, link) {
1003 unsigned long a = node->userspace_addr;
1004
1005 if (vhost_overflow(node->userspace_addr, node->size))
1006 return false;
1007
1008
1009 if (!access_ok((void __user *)a,
1010 node->size))
1011 return false;
1012 else if (log_all && !log_access_ok(log_base,
1013 node->start,
1014 node->size))
1015 return false;
1016 }
1017 return true;
1018 }
1019
1020 static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq,
1021 u64 addr, unsigned int size,
1022 int type)
1023 {
1024 const struct vhost_umem_node *node = vq->meta_iotlb[type];
1025
1026 if (!node)
1027 return NULL;
1028
1029 return (void *)(uintptr_t)(node->userspace_addr + addr - node->start);
1030 }
1031
1032 /* Can we switch to this memory table? */
1033 /* Caller should have device mutex but not vq mutex */
1034 static bool memory_access_ok(struct vhost_dev *d, struct vhost_umem *umem,
1035 int log_all)
1036 {
1037 int i;
1038
1039 for (i = 0; i < d->nvqs; ++i) {
1040 bool ok;
1041 bool log;
1042
1043 mutex_lock(&d->vqs[i]->mutex);
1044 log = log_all || vhost_has_feature(d->vqs[i], VHOST_F_LOG_ALL);
1045 /* If ring is inactive, will check when it's enabled. */
1046 if (d->vqs[i]->private_data)
1047 ok = vq_memory_access_ok(d->vqs[i]->log_base,
1048 umem, log);
1049 else
1050 ok = true;
1051 mutex_unlock(&d->vqs[i]->mutex);
1052 if (!ok)
1053 return false;
1054 }
1055 return true;
1056 }
1057
1058 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
1059 struct iovec iov[], int iov_size, int access);
1060
1061 static int vhost_copy_to_user(struct vhost_virtqueue *vq, void __user *to,
1062 const void *from, unsigned size)
1063 {
1064 int ret;
1065
1066 if (!vq->iotlb)
1067 return __copy_to_user(to, from, size);
1068 else {
1069 /* This function should be called after iotlb
1070 * prefetch, which means we're sure that all vq
1071 * could be access through iotlb. So -EAGAIN should
1072 * not happen in this case.
1073 */
1074 struct iov_iter t;
1075 void __user *uaddr = vhost_vq_meta_fetch(vq,
1076 (u64)(uintptr_t)to, size,
1077 VHOST_ADDR_USED);
1078
1079 if (uaddr)
1080 return __copy_to_user(uaddr, from, size);
1081
1082 ret = translate_desc(vq, (u64)(uintptr_t)to, size, vq->iotlb_iov,
1083 ARRAY_SIZE(vq->iotlb_iov),
1084 VHOST_ACCESS_WO);
1085 if (ret < 0)
1086 goto out;
1087 iov_iter_init(&t, WRITE, vq->iotlb_iov, ret, size);
1088 ret = copy_to_iter(from, size, &t);
1089 if (ret == size)
1090 ret = 0;
1091 }
1092 out:
1093 return ret;
1094 }
1095
1096 static int vhost_copy_from_user(struct vhost_virtqueue *vq, void *to,
1097 void __user *from, unsigned size)
1098 {
1099 int ret;
1100
1101 if (!vq->iotlb)
1102 return __copy_from_user(to, from, size);
1103 else {
1104 /* This function should be called after iotlb
1105 * prefetch, which means we're sure that vq
1106 * could be access through iotlb. So -EAGAIN should
1107 * not happen in this case.
1108 */
1109 void __user *uaddr = vhost_vq_meta_fetch(vq,
1110 (u64)(uintptr_t)from, size,
1111 VHOST_ADDR_DESC);
1112 struct iov_iter f;
1113
1114 if (uaddr)
1115 return __copy_from_user(to, uaddr, size);
1116
1117 ret = translate_desc(vq, (u64)(uintptr_t)from, size, vq->iotlb_iov,
1118 ARRAY_SIZE(vq->iotlb_iov),
1119 VHOST_ACCESS_RO);
1120 if (ret < 0) {
1121 vq_err(vq, "IOTLB translation failure: uaddr "
1122 "%p size 0x%llx\n", from,
1123 (unsigned long long) size);
1124 goto out;
1125 }
1126 iov_iter_init(&f, READ, vq->iotlb_iov, ret, size);
1127 ret = copy_from_iter(to, size, &f);
1128 if (ret == size)
1129 ret = 0;
1130 }
1131
1132 out:
1133 return ret;
1134 }
1135
1136 static void __user *__vhost_get_user_slow(struct vhost_virtqueue *vq,
1137 void __user *addr, unsigned int size,
1138 int type)
1139 {
1140 int ret;
1141
1142 ret = translate_desc(vq, (u64)(uintptr_t)addr, size, vq->iotlb_iov,
1143 ARRAY_SIZE(vq->iotlb_iov),
1144 VHOST_ACCESS_RO);
1145 if (ret < 0) {
1146 vq_err(vq, "IOTLB translation failure: uaddr "
1147 "%p size 0x%llx\n", addr,
1148 (unsigned long long) size);
1149 return NULL;
1150 }
1151
1152 if (ret != 1 || vq->iotlb_iov[0].iov_len != size) {
1153 vq_err(vq, "Non atomic userspace memory access: uaddr "
1154 "%p size 0x%llx\n", addr,
1155 (unsigned long long) size);
1156 return NULL;
1157 }
1158
1159 return vq->iotlb_iov[0].iov_base;
1160 }
1161
1162 /* This function should be called after iotlb
1163 * prefetch, which means we're sure that vq
1164 * could be access through iotlb. So -EAGAIN should
1165 * not happen in this case.
1166 */
1167 static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq,
1168 void *addr, unsigned int size,
1169 int type)
1170 {
1171 void __user *uaddr = vhost_vq_meta_fetch(vq,
1172 (u64)(uintptr_t)addr, size, type);
1173 if (uaddr)
1174 return uaddr;
1175
1176 return __vhost_get_user_slow(vq, addr, size, type);
1177 }
1178
1179 #define vhost_put_user(vq, x, ptr) \
1180 ({ \
1181 int ret = -EFAULT; \
1182 if (!vq->iotlb) { \
1183 ret = __put_user(x, ptr); \
1184 } else { \
1185 __typeof__(ptr) to = \
1186 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
1187 sizeof(*ptr), VHOST_ADDR_USED); \
1188 if (to != NULL) \
1189 ret = __put_user(x, to); \
1190 else \
1191 ret = -EFAULT; \
1192 } \
1193 ret; \
1194 })
1195
1196 static inline int vhost_put_avail_event(struct vhost_virtqueue *vq)
1197 {
1198 #if VHOST_ARCH_CAN_ACCEL_UACCESS
1199 struct vhost_map *map;
1200 struct vring_used *used;
1201
1202 if (!vq->iotlb) {
1203 rcu_read_lock();
1204
1205 map = rcu_dereference(vq->maps[VHOST_ADDR_USED]);
1206 if (likely(map)) {
1207 used = map->addr;
1208 *((__virtio16 *)&used->ring[vq->num]) =
1209 cpu_to_vhost16(vq, vq->avail_idx);
1210 rcu_read_unlock();
1211 return 0;
1212 }
1213
1214 rcu_read_unlock();
1215 }
1216 #endif
1217
1218 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx),
1219 vhost_avail_event(vq));
1220 }
1221
1222 static inline int vhost_put_used(struct vhost_virtqueue *vq,
1223 struct vring_used_elem *head, int idx,
1224 int count)
1225 {
1226 #if VHOST_ARCH_CAN_ACCEL_UACCESS
1227 struct vhost_map *map;
1228 struct vring_used *used;
1229 size_t size;
1230
1231 if (!vq->iotlb) {
1232 rcu_read_lock();
1233
1234 map = rcu_dereference(vq->maps[VHOST_ADDR_USED]);
1235 if (likely(map)) {
1236 used = map->addr;
1237 size = count * sizeof(*head);
1238 memcpy(used->ring + idx, head, size);
1239 rcu_read_unlock();
1240 return 0;
1241 }
1242
1243 rcu_read_unlock();
1244 }
1245 #endif
1246
1247 return vhost_copy_to_user(vq, vq->used->ring + idx, head,
1248 count * sizeof(*head));
1249 }
1250
1251 static inline int vhost_put_used_flags(struct vhost_virtqueue *vq)
1252
1253 {
1254 #if VHOST_ARCH_CAN_ACCEL_UACCESS
1255 struct vhost_map *map;
1256 struct vring_used *used;
1257
1258 if (!vq->iotlb) {
1259 rcu_read_lock();
1260
1261 map = rcu_dereference(vq->maps[VHOST_ADDR_USED]);
1262 if (likely(map)) {
1263 used = map->addr;
1264 used->flags = cpu_to_vhost16(vq, vq->used_flags);
1265 rcu_read_unlock();
1266 return 0;
1267 }
1268
1269 rcu_read_unlock();
1270 }
1271 #endif
1272
1273 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags),
1274 &vq->used->flags);
1275 }
1276
1277 static inline int vhost_put_used_idx(struct vhost_virtqueue *vq)
1278
1279 {
1280 #if VHOST_ARCH_CAN_ACCEL_UACCESS
1281 struct vhost_map *map;
1282 struct vring_used *used;
1283
1284 if (!vq->iotlb) {
1285 rcu_read_lock();
1286
1287 map = rcu_dereference(vq->maps[VHOST_ADDR_USED]);
1288 if (likely(map)) {
1289 used = map->addr;
1290 used->idx = cpu_to_vhost16(vq, vq->last_used_idx);
1291 rcu_read_unlock();
1292 return 0;
1293 }
1294
1295 rcu_read_unlock();
1296 }
1297 #endif
1298
1299 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx),
1300 &vq->used->idx);
1301 }
1302
1303 #define vhost_get_user(vq, x, ptr, type) \
1304 ({ \
1305 int ret; \
1306 if (!vq->iotlb) { \
1307 ret = __get_user(x, ptr); \
1308 } else { \
1309 __typeof__(ptr) from = \
1310 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
1311 sizeof(*ptr), \
1312 type); \
1313 if (from != NULL) \
1314 ret = __get_user(x, from); \
1315 else \
1316 ret = -EFAULT; \
1317 } \
1318 ret; \
1319 })
1320
1321 #define vhost_get_avail(vq, x, ptr) \
1322 vhost_get_user(vq, x, ptr, VHOST_ADDR_AVAIL)
1323
1324 #define vhost_get_used(vq, x, ptr) \
1325 vhost_get_user(vq, x, ptr, VHOST_ADDR_USED)
1326
1327 static void vhost_dev_lock_vqs(struct vhost_dev *d)
1328 {
1329 int i = 0;
1330 for (i = 0; i < d->nvqs; ++i)
1331 mutex_lock_nested(&d->vqs[i]->mutex, i);
1332 }
1333
1334 static void vhost_dev_unlock_vqs(struct vhost_dev *d)
1335 {
1336 int i = 0;
1337 for (i = 0; i < d->nvqs; ++i)
1338 mutex_unlock(&d->vqs[i]->mutex);
1339 }
1340
1341 static inline int vhost_get_avail_idx(struct vhost_virtqueue *vq,
1342 __virtio16 *idx)
1343 {
1344 #if VHOST_ARCH_CAN_ACCEL_UACCESS
1345 struct vhost_map *map;
1346 struct vring_avail *avail;
1347
1348 if (!vq->iotlb) {
1349 rcu_read_lock();
1350
1351 map = rcu_dereference(vq->maps[VHOST_ADDR_AVAIL]);
1352 if (likely(map)) {
1353 avail = map->addr;
1354 *idx = avail->idx;
1355 rcu_read_unlock();
1356 return 0;
1357 }
1358
1359 rcu_read_unlock();
1360 }
1361 #endif
1362
1363 return vhost_get_avail(vq, *idx, &vq->avail->idx);
1364 }
1365
1366 static inline int vhost_get_avail_head(struct vhost_virtqueue *vq,
1367 __virtio16 *head, int idx)
1368 {
1369 #if VHOST_ARCH_CAN_ACCEL_UACCESS
1370 struct vhost_map *map;
1371 struct vring_avail *avail;
1372
1373 if (!vq->iotlb) {
1374 rcu_read_lock();
1375
1376 map = rcu_dereference(vq->maps[VHOST_ADDR_AVAIL]);
1377 if (likely(map)) {
1378 avail = map->addr;
1379 *head = avail->ring[idx & (vq->num - 1)];
1380 rcu_read_unlock();
1381 return 0;
1382 }
1383
1384 rcu_read_unlock();
1385 }
1386 #endif
1387
1388 return vhost_get_avail(vq, *head,
1389 &vq->avail->ring[idx & (vq->num - 1)]);
1390 }
1391
1392 static inline int vhost_get_avail_flags(struct vhost_virtqueue *vq,
1393 __virtio16 *flags)
1394 {
1395 #if VHOST_ARCH_CAN_ACCEL_UACCESS
1396 struct vhost_map *map;
1397 struct vring_avail *avail;
1398
1399 if (!vq->iotlb) {
1400 rcu_read_lock();
1401
1402 map = rcu_dereference(vq->maps[VHOST_ADDR_AVAIL]);
1403 if (likely(map)) {
1404 avail = map->addr;
1405 *flags = avail->flags;
1406 rcu_read_unlock();
1407 return 0;
1408 }
1409
1410 rcu_read_unlock();
1411 }
1412 #endif
1413
1414 return vhost_get_avail(vq, *flags, &vq->avail->flags);
1415 }
1416
1417 static inline int vhost_get_used_event(struct vhost_virtqueue *vq,
1418 __virtio16 *event)
1419 {
1420 #if VHOST_ARCH_CAN_ACCEL_UACCESS
1421 struct vhost_map *map;
1422 struct vring_avail *avail;
1423
1424 if (!vq->iotlb) {
1425 rcu_read_lock();
1426 map = rcu_dereference(vq->maps[VHOST_ADDR_AVAIL]);
1427 if (likely(map)) {
1428 avail = map->addr;
1429 *event = (__virtio16)avail->ring[vq->num];
1430 rcu_read_unlock();
1431 return 0;
1432 }
1433 rcu_read_unlock();
1434 }
1435 #endif
1436
1437 return vhost_get_avail(vq, *event, vhost_used_event(vq));
1438 }
1439
1440 static inline int vhost_get_used_idx(struct vhost_virtqueue *vq,
1441 __virtio16 *idx)
1442 {
1443 #if VHOST_ARCH_CAN_ACCEL_UACCESS
1444 struct vhost_map *map;
1445 struct vring_used *used;
1446
1447 if (!vq->iotlb) {
1448 rcu_read_lock();
1449
1450 map = rcu_dereference(vq->maps[VHOST_ADDR_USED]);
1451 if (likely(map)) {
1452 used = map->addr;
1453 *idx = used->idx;
1454 rcu_read_unlock();
1455 return 0;
1456 }
1457
1458 rcu_read_unlock();
1459 }
1460 #endif
1461
1462 return vhost_get_used(vq, *idx, &vq->used->idx);
1463 }
1464
1465 static inline int vhost_get_desc(struct vhost_virtqueue *vq,
1466 struct vring_desc *desc, int idx)
1467 {
1468 #if VHOST_ARCH_CAN_ACCEL_UACCESS
1469 struct vhost_map *map;
1470 struct vring_desc *d;
1471
1472 if (!vq->iotlb) {
1473 rcu_read_lock();
1474
1475 map = rcu_dereference(vq->maps[VHOST_ADDR_DESC]);
1476 if (likely(map)) {
1477 d = map->addr;
1478 *desc = *(d + idx);
1479 rcu_read_unlock();
1480 return 0;
1481 }
1482
1483 rcu_read_unlock();
1484 }
1485 #endif
1486
1487 return vhost_copy_from_user(vq, desc, vq->desc + idx, sizeof(*desc));
1488 }
1489
1490 static int vhost_new_umem_range(struct vhost_umem *umem,
1491 u64 start, u64 size, u64 end,
1492 u64 userspace_addr, int perm)
1493 {
1494 struct vhost_umem_node *tmp, *node;
1495
1496 if (!size)
1497 return -EFAULT;
1498
1499 node = kmalloc(sizeof(*node), GFP_ATOMIC);
1500 if (!node)
1501 return -ENOMEM;
1502
1503 if (umem->numem == max_iotlb_entries) {
1504 tmp = list_first_entry(&umem->umem_list, typeof(*tmp), link);
1505 vhost_umem_free(umem, tmp);
1506 }
1507
1508 node->start = start;
1509 node->size = size;
1510 node->last = end;
1511 node->userspace_addr = userspace_addr;
1512 node->perm = perm;
1513 INIT_LIST_HEAD(&node->link);
1514 list_add_tail(&node->link, &umem->umem_list);
1515 vhost_umem_interval_tree_insert(node, &umem->umem_tree);
1516 umem->numem++;
1517
1518 return 0;
1519 }
1520
1521 static void vhost_del_umem_range(struct vhost_umem *umem,
1522 u64 start, u64 end)
1523 {
1524 struct vhost_umem_node *node;
1525
1526 while ((node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
1527 start, end)))
1528 vhost_umem_free(umem, node);
1529 }
1530
1531 static void vhost_iotlb_notify_vq(struct vhost_dev *d,
1532 struct vhost_iotlb_msg *msg)
1533 {
1534 struct vhost_msg_node *node, *n;
1535
1536 spin_lock(&d->iotlb_lock);
1537
1538 list_for_each_entry_safe(node, n, &d->pending_list, node) {
1539 struct vhost_iotlb_msg *vq_msg = &node->msg.iotlb;
1540 if (msg->iova <= vq_msg->iova &&
1541 msg->iova + msg->size - 1 >= vq_msg->iova &&
1542 vq_msg->type == VHOST_IOTLB_MISS) {
1543 vhost_poll_queue(&node->vq->poll);
1544 list_del(&node->node);
1545 kfree(node);
1546 }
1547 }
1548
1549 spin_unlock(&d->iotlb_lock);
1550 }
1551
1552 static bool umem_access_ok(u64 uaddr, u64 size, int access)
1553 {
1554 unsigned long a = uaddr;
1555
1556 /* Make sure 64 bit math will not overflow. */
1557 if (vhost_overflow(uaddr, size))
1558 return false;
1559
1560 if ((access & VHOST_ACCESS_RO) &&
1561 !access_ok((void __user *)a, size))
1562 return false;
1563 if ((access & VHOST_ACCESS_WO) &&
1564 !access_ok((void __user *)a, size))
1565 return false;
1566 return true;
1567 }
1568
1569 static int vhost_process_iotlb_msg(struct vhost_dev *dev,
1570 struct vhost_iotlb_msg *msg)
1571 {
1572 int ret = 0;
1573
1574 mutex_lock(&dev->mutex);
1575 vhost_dev_lock_vqs(dev);
1576 switch (msg->type) {
1577 case VHOST_IOTLB_UPDATE:
1578 if (!dev->iotlb) {
1579 ret = -EFAULT;
1580 break;
1581 }
1582 if (!umem_access_ok(msg->uaddr, msg->size, msg->perm)) {
1583 ret = -EFAULT;
1584 break;
1585 }
1586 vhost_vq_meta_reset(dev);
1587 if (vhost_new_umem_range(dev->iotlb, msg->iova, msg->size,
1588 msg->iova + msg->size - 1,
1589 msg->uaddr, msg->perm)) {
1590 ret = -ENOMEM;
1591 break;
1592 }
1593 vhost_iotlb_notify_vq(dev, msg);
1594 break;
1595 case VHOST_IOTLB_INVALIDATE:
1596 if (!dev->iotlb) {
1597 ret = -EFAULT;
1598 break;
1599 }
1600 vhost_vq_meta_reset(dev);
1601 vhost_del_umem_range(dev->iotlb, msg->iova,
1602 msg->iova + msg->size - 1);
1603 break;
1604 default:
1605 ret = -EINVAL;
1606 break;
1607 }
1608
1609 vhost_dev_unlock_vqs(dev);
1610 mutex_unlock(&dev->mutex);
1611
1612 return ret;
1613 }
1614 ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
1615 struct iov_iter *from)
1616 {
1617 struct vhost_iotlb_msg msg;
1618 size_t offset;
1619 int type, ret;
1620
1621 ret = copy_from_iter(&type, sizeof(type), from);
1622 if (ret != sizeof(type)) {
1623 ret = -EINVAL;
1624 goto done;
1625 }
1626
1627 switch (type) {
1628 case VHOST_IOTLB_MSG:
1629 /* There maybe a hole after type for V1 message type,
1630 * so skip it here.
1631 */
1632 offset = offsetof(struct vhost_msg, iotlb) - sizeof(int);
1633 break;
1634 case VHOST_IOTLB_MSG_V2:
1635 offset = sizeof(__u32);
1636 break;
1637 default:
1638 ret = -EINVAL;
1639 goto done;
1640 }
1641
1642 iov_iter_advance(from, offset);
1643 ret = copy_from_iter(&msg, sizeof(msg), from);
1644 if (ret != sizeof(msg)) {
1645 ret = -EINVAL;
1646 goto done;
1647 }
1648 if (vhost_process_iotlb_msg(dev, &msg)) {
1649 ret = -EFAULT;
1650 goto done;
1651 }
1652
1653 ret = (type == VHOST_IOTLB_MSG) ? sizeof(struct vhost_msg) :
1654 sizeof(struct vhost_msg_v2);
1655 done:
1656 return ret;
1657 }
1658 EXPORT_SYMBOL(vhost_chr_write_iter);
1659
1660 __poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
1661 poll_table *wait)
1662 {
1663 __poll_t mask = 0;
1664
1665 poll_wait(file, &dev->wait, wait);
1666
1667 if (!list_empty(&dev->read_list))
1668 mask |= EPOLLIN | EPOLLRDNORM;
1669
1670 return mask;
1671 }
1672 EXPORT_SYMBOL(vhost_chr_poll);
1673
1674 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
1675 int noblock)
1676 {
1677 DEFINE_WAIT(wait);
1678 struct vhost_msg_node *node;
1679 ssize_t ret = 0;
1680 unsigned size = sizeof(struct vhost_msg);
1681
1682 if (iov_iter_count(to) < size)
1683 return 0;
1684
1685 while (1) {
1686 if (!noblock)
1687 prepare_to_wait(&dev->wait, &wait,
1688 TASK_INTERRUPTIBLE);
1689
1690 node = vhost_dequeue_msg(dev, &dev->read_list);
1691 if (node)
1692 break;
1693 if (noblock) {
1694 ret = -EAGAIN;
1695 break;
1696 }
1697 if (signal_pending(current)) {
1698 ret = -ERESTARTSYS;
1699 break;
1700 }
1701 if (!dev->iotlb) {
1702 ret = -EBADFD;
1703 break;
1704 }
1705
1706 schedule();
1707 }
1708
1709 if (!noblock)
1710 finish_wait(&dev->wait, &wait);
1711
1712 if (node) {
1713 struct vhost_iotlb_msg *msg;
1714 void *start = &node->msg;
1715
1716 switch (node->msg.type) {
1717 case VHOST_IOTLB_MSG:
1718 size = sizeof(node->msg);
1719 msg = &node->msg.iotlb;
1720 break;
1721 case VHOST_IOTLB_MSG_V2:
1722 size = sizeof(node->msg_v2);
1723 msg = &node->msg_v2.iotlb;
1724 break;
1725 default:
1726 BUG();
1727 break;
1728 }
1729
1730 ret = copy_to_iter(start, size, to);
1731 if (ret != size || msg->type != VHOST_IOTLB_MISS) {
1732 kfree(node);
1733 return ret;
1734 }
1735 vhost_enqueue_msg(dev, &dev->pending_list, node);
1736 }
1737
1738 return ret;
1739 }
1740 EXPORT_SYMBOL_GPL(vhost_chr_read_iter);
1741
1742 static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access)
1743 {
1744 struct vhost_dev *dev = vq->dev;
1745 struct vhost_msg_node *node;
1746 struct vhost_iotlb_msg *msg;
1747 bool v2 = vhost_backend_has_feature(vq, VHOST_BACKEND_F_IOTLB_MSG_V2);
1748
1749 node = vhost_new_msg(vq, v2 ? VHOST_IOTLB_MSG_V2 : VHOST_IOTLB_MSG);
1750 if (!node)
1751 return -ENOMEM;
1752
1753 if (v2) {
1754 node->msg_v2.type = VHOST_IOTLB_MSG_V2;
1755 msg = &node->msg_v2.iotlb;
1756 } else {
1757 msg = &node->msg.iotlb;
1758 }
1759
1760 msg->type = VHOST_IOTLB_MISS;
1761 msg->iova = iova;
1762 msg->perm = access;
1763
1764 vhost_enqueue_msg(dev, &dev->read_list, node);
1765
1766 return 0;
1767 }
1768
1769 static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
1770 struct vring_desc __user *desc,
1771 struct vring_avail __user *avail,
1772 struct vring_used __user *used)
1773
1774 {
1775 return access_ok(desc, vhost_get_desc_size(vq, num)) &&
1776 access_ok(avail, vhost_get_avail_size(vq, num)) &&
1777 access_ok(used, vhost_get_used_size(vq, num));
1778 }
1779
1780 static void vhost_vq_meta_update(struct vhost_virtqueue *vq,
1781 const struct vhost_umem_node *node,
1782 int type)
1783 {
1784 int access = (type == VHOST_ADDR_USED) ?
1785 VHOST_ACCESS_WO : VHOST_ACCESS_RO;
1786
1787 if (likely(node->perm & access))
1788 vq->meta_iotlb[type] = node;
1789 }
1790
1791 static bool iotlb_access_ok(struct vhost_virtqueue *vq,
1792 int access, u64 addr, u64 len, int type)
1793 {
1794 const struct vhost_umem_node *node;
1795 struct vhost_umem *umem = vq->iotlb;
1796 u64 s = 0, size, orig_addr = addr, last = addr + len - 1;
1797
1798 if (vhost_vq_meta_fetch(vq, addr, len, type))
1799 return true;
1800
1801 while (len > s) {
1802 node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
1803 addr,
1804 last);
1805 if (node == NULL || node->start > addr) {
1806 vhost_iotlb_miss(vq, addr, access);
1807 return false;
1808 } else if (!(node->perm & access)) {
1809 /* Report the possible access violation by
1810 * request another translation from userspace.
1811 */
1812 return false;
1813 }
1814
1815 size = node->size - addr + node->start;
1816
1817 if (orig_addr == addr && size >= len)
1818 vhost_vq_meta_update(vq, node, type);
1819
1820 s += size;
1821 addr += size;
1822 }
1823
1824 return true;
1825 }
1826
1827 #if VHOST_ARCH_CAN_ACCEL_UACCESS
1828 static void vhost_vq_map_prefetch(struct vhost_virtqueue *vq)
1829 {
1830 struct vhost_map __rcu *map;
1831 int i;
1832
1833 for (i = 0; i < VHOST_NUM_ADDRS; i++) {
1834 rcu_read_lock();
1835 map = rcu_dereference(vq->maps[i]);
1836 rcu_read_unlock();
1837 if (unlikely(!map))
1838 vhost_map_prefetch(vq, i);
1839 }
1840 }
1841 #endif
1842
1843 int vq_meta_prefetch(struct vhost_virtqueue *vq)
1844 {
1845 unsigned int num = vq->num;
1846
1847 if (!vq->iotlb) {
1848 #if VHOST_ARCH_CAN_ACCEL_UACCESS
1849 vhost_vq_map_prefetch(vq);
1850 #endif
1851 return 1;
1852 }
1853
1854 return iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->desc,
1855 vhost_get_desc_size(vq, num), VHOST_ADDR_DESC) &&
1856 iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->avail,
1857 vhost_get_avail_size(vq, num),
1858 VHOST_ADDR_AVAIL) &&
1859 iotlb_access_ok(vq, VHOST_ACCESS_WO, (u64)(uintptr_t)vq->used,
1860 vhost_get_used_size(vq, num), VHOST_ADDR_USED);
1861 }
1862 EXPORT_SYMBOL_GPL(vq_meta_prefetch);
1863
1864 /* Can we log writes? */
1865 /* Caller should have device mutex but not vq mutex */
1866 bool vhost_log_access_ok(struct vhost_dev *dev)
1867 {
1868 return memory_access_ok(dev, dev->umem, 1);
1869 }
1870 EXPORT_SYMBOL_GPL(vhost_log_access_ok);
1871
1872 /* Verify access for write logging. */
1873 /* Caller should have vq mutex and device mutex */
1874 static bool vq_log_access_ok(struct vhost_virtqueue *vq,
1875 void __user *log_base)
1876 {
1877 return vq_memory_access_ok(log_base, vq->umem,
1878 vhost_has_feature(vq, VHOST_F_LOG_ALL)) &&
1879 (!vq->log_used || log_access_ok(log_base, vq->log_addr,
1880 vhost_get_used_size(vq, vq->num)));
1881 }
1882
1883 /* Can we start vq? */
1884 /* Caller should have vq mutex and device mutex */
1885 bool vhost_vq_access_ok(struct vhost_virtqueue *vq)
1886 {
1887 if (!vq_log_access_ok(vq, vq->log_base))
1888 return false;
1889
1890 /* Access validation occurs at prefetch time with IOTLB */
1891 if (vq->iotlb)
1892 return true;
1893
1894 return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used);
1895 }
1896 EXPORT_SYMBOL_GPL(vhost_vq_access_ok);
1897
1898 static struct vhost_umem *vhost_umem_alloc(void)
1899 {
1900 struct vhost_umem *umem = kvzalloc(sizeof(*umem), GFP_KERNEL);
1901
1902 if (!umem)
1903 return NULL;
1904
1905 umem->umem_tree = RB_ROOT_CACHED;
1906 umem->numem = 0;
1907 INIT_LIST_HEAD(&umem->umem_list);
1908
1909 return umem;
1910 }
1911
1912 static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
1913 {
1914 struct vhost_memory mem, *newmem;
1915 struct vhost_memory_region *region;
1916 struct vhost_umem *newumem, *oldumem;
1917 unsigned long size = offsetof(struct vhost_memory, regions);
1918 int i;
1919
1920 if (copy_from_user(&mem, m, size))
1921 return -EFAULT;
1922 if (mem.padding)
1923 return -EOPNOTSUPP;
1924 if (mem.nregions > max_mem_regions)
1925 return -E2BIG;
1926 newmem = kvzalloc(struct_size(newmem, regions, mem.nregions),
1927 GFP_KERNEL);
1928 if (!newmem)
1929 return -ENOMEM;
1930
1931 memcpy(newmem, &mem, size);
1932 if (copy_from_user(newmem->regions, m->regions,
1933 mem.nregions * sizeof *m->regions)) {
1934 kvfree(newmem);
1935 return -EFAULT;
1936 }
1937
1938 newumem = vhost_umem_alloc();
1939 if (!newumem) {
1940 kvfree(newmem);
1941 return -ENOMEM;
1942 }
1943
1944 for (region = newmem->regions;
1945 region < newmem->regions + mem.nregions;
1946 region++) {
1947 if (vhost_new_umem_range(newumem,
1948 region->guest_phys_addr,
1949 region->memory_size,
1950 region->guest_phys_addr +
1951 region->memory_size - 1,
1952 region->userspace_addr,
1953 VHOST_ACCESS_RW))
1954 goto err;
1955 }
1956
1957 if (!memory_access_ok(d, newumem, 0))
1958 goto err;
1959
1960 oldumem = d->umem;
1961 d->umem = newumem;
1962
1963 /* All memory accesses are done under some VQ mutex. */
1964 for (i = 0; i < d->nvqs; ++i) {
1965 mutex_lock(&d->vqs[i]->mutex);
1966 d->vqs[i]->umem = newumem;
1967 mutex_unlock(&d->vqs[i]->mutex);
1968 }
1969
1970 kvfree(newmem);
1971 vhost_umem_clean(oldumem);
1972 return 0;
1973
1974 err:
1975 vhost_umem_clean(newumem);
1976 kvfree(newmem);
1977 return -EFAULT;
1978 }
1979
1980 static long vhost_vring_set_num(struct vhost_dev *d,
1981 struct vhost_virtqueue *vq,
1982 void __user *argp)
1983 {
1984 struct vhost_vring_state s;
1985
1986 /* Resizing ring with an active backend?
1987 * You don't want to do that. */
1988 if (vq->private_data)
1989 return -EBUSY;
1990
1991 if (copy_from_user(&s, argp, sizeof s))
1992 return -EFAULT;
1993
1994 if (!s.num || s.num > 0xffff || (s.num & (s.num - 1)))
1995 return -EINVAL;
1996 vq->num = s.num;
1997
1998 return 0;
1999 }
2000
2001 static long vhost_vring_set_addr(struct vhost_dev *d,
2002 struct vhost_virtqueue *vq,
2003 void __user *argp)
2004 {
2005 struct vhost_vring_addr a;
2006
2007 if (copy_from_user(&a, argp, sizeof a))
2008 return -EFAULT;
2009 if (a.flags & ~(0x1 << VHOST_VRING_F_LOG))
2010 return -EOPNOTSUPP;
2011
2012 /* For 32bit, verify that the top 32bits of the user
2013 data are set to zero. */
2014 if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr ||
2015 (u64)(unsigned long)a.used_user_addr != a.used_user_addr ||
2016 (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr)
2017 return -EFAULT;
2018
2019 /* Make sure it's safe to cast pointers to vring types. */
2020 BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE);
2021 BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE);
2022 if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) ||
2023 (a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) ||
2024 (a.log_guest_addr & (VRING_USED_ALIGN_SIZE - 1)))
2025 return -EINVAL;
2026
2027 /* We only verify access here if backend is configured.
2028 * If it is not, we don't as size might not have been setup.
2029 * We will verify when backend is configured. */
2030 if (vq->private_data) {
2031 if (!vq_access_ok(vq, vq->num,
2032 (void __user *)(unsigned long)a.desc_user_addr,
2033 (void __user *)(unsigned long)a.avail_user_addr,
2034 (void __user *)(unsigned long)a.used_user_addr))
2035 return -EINVAL;
2036
2037 /* Also validate log access for used ring if enabled. */
2038 if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) &&
2039 !log_access_ok(vq->log_base, a.log_guest_addr,
2040 sizeof *vq->used +
2041 vq->num * sizeof *vq->used->ring))
2042 return -EINVAL;
2043 }
2044
2045 vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG));
2046 vq->desc = (void __user *)(unsigned long)a.desc_user_addr;
2047 vq->avail = (void __user *)(unsigned long)a.avail_user_addr;
2048 vq->log_addr = a.log_guest_addr;
2049 vq->used = (void __user *)(unsigned long)a.used_user_addr;
2050
2051 return 0;
2052 }
2053
2054 static long vhost_vring_set_num_addr(struct vhost_dev *d,
2055 struct vhost_virtqueue *vq,
2056 unsigned int ioctl,
2057 void __user *argp)
2058 {
2059 long r;
2060
2061 mutex_lock(&vq->mutex);
2062
2063 #if VHOST_ARCH_CAN_ACCEL_UACCESS
2064 /* Unregister MMU notifer to allow invalidation callback
2065 * can access vq->uaddrs[] without holding a lock.
2066 */
2067 if (d->mm)
2068 mmu_notifier_unregister(&d->mmu_notifier, d->mm);
2069
2070 vhost_uninit_vq_maps(vq);
2071 #endif
2072
2073 switch (ioctl) {
2074 case VHOST_SET_VRING_NUM:
2075 r = vhost_vring_set_num(d, vq, argp);
2076 break;
2077 case VHOST_SET_VRING_ADDR:
2078 r = vhost_vring_set_addr(d, vq, argp);
2079 break;
2080 default:
2081 BUG();
2082 }
2083
2084 #if VHOST_ARCH_CAN_ACCEL_UACCESS
2085 vhost_setup_vq_uaddr(vq);
2086
2087 if (d->mm)
2088 mmu_notifier_register(&d->mmu_notifier, d->mm);
2089 #endif
2090
2091 mutex_unlock(&vq->mutex);
2092
2093 return r;
2094 }
2095 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
2096 {
2097 struct file *eventfp, *filep = NULL;
2098 bool pollstart = false, pollstop = false;
2099 struct eventfd_ctx *ctx = NULL;
2100 u32 __user *idxp = argp;
2101 struct vhost_virtqueue *vq;
2102 struct vhost_vring_state s;
2103 struct vhost_vring_file f;
2104 u32 idx;
2105 long r;
2106
2107 r = get_user(idx, idxp);
2108 if (r < 0)
2109 return r;
2110 if (idx >= d->nvqs)
2111 return -ENOBUFS;
2112
2113 idx = array_index_nospec(idx, d->nvqs);
2114 vq = d->vqs[idx];
2115
2116 if (ioctl == VHOST_SET_VRING_NUM ||
2117 ioctl == VHOST_SET_VRING_ADDR) {
2118 return vhost_vring_set_num_addr(d, vq, ioctl, argp);
2119 }
2120
2121 mutex_lock(&vq->mutex);
2122
2123 switch (ioctl) {
2124 case VHOST_SET_VRING_BASE:
2125 /* Moving base with an active backend?
2126 * You don't want to do that. */
2127 if (vq->private_data) {
2128 r = -EBUSY;
2129 break;
2130 }
2131 if (copy_from_user(&s, argp, sizeof s)) {
2132 r = -EFAULT;
2133 break;
2134 }
2135 if (s.num > 0xffff) {
2136 r = -EINVAL;
2137 break;
2138 }
2139 vq->last_avail_idx = s.num;
2140 /* Forget the cached index value. */
2141 vq->avail_idx = vq->last_avail_idx;
2142 break;
2143 case VHOST_GET_VRING_BASE:
2144 s.index = idx;
2145 s.num = vq->last_avail_idx;
2146 if (copy_to_user(argp, &s, sizeof s))
2147 r = -EFAULT;
2148 break;
2149 case VHOST_SET_VRING_KICK:
2150 if (copy_from_user(&f, argp, sizeof f)) {
2151 r = -EFAULT;
2152 break;
2153 }
2154 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
2155 if (IS_ERR(eventfp)) {
2156 r = PTR_ERR(eventfp);
2157 break;
2158 }
2159 if (eventfp != vq->kick) {
2160 pollstop = (filep = vq->kick) != NULL;
2161 pollstart = (vq->kick = eventfp) != NULL;
2162 } else
2163 filep = eventfp;
2164 break;
2165 case VHOST_SET_VRING_CALL:
2166 if (copy_from_user(&f, argp, sizeof f)) {
2167 r = -EFAULT;
2168 break;
2169 }
2170 ctx = f.fd == -1 ? NULL : eventfd_ctx_fdget(f.fd);
2171 if (IS_ERR(ctx)) {
2172 r = PTR_ERR(ctx);
2173 break;
2174 }
2175 swap(ctx, vq->call_ctx);
2176 break;
2177 case VHOST_SET_VRING_ERR:
2178 if (copy_from_user(&f, argp, sizeof f)) {
2179 r = -EFAULT;
2180 break;
2181 }
2182 ctx = f.fd == -1 ? NULL : eventfd_ctx_fdget(f.fd);
2183 if (IS_ERR(ctx)) {
2184 r = PTR_ERR(ctx);
2185 break;
2186 }
2187 swap(ctx, vq->error_ctx);
2188 break;
2189 case VHOST_SET_VRING_ENDIAN:
2190 r = vhost_set_vring_endian(vq, argp);
2191 break;
2192 case VHOST_GET_VRING_ENDIAN:
2193 r = vhost_get_vring_endian(vq, idx, argp);
2194 break;
2195 case VHOST_SET_VRING_BUSYLOOP_TIMEOUT:
2196 if (copy_from_user(&s, argp, sizeof(s))) {
2197 r = -EFAULT;
2198 break;
2199 }
2200 vq->busyloop_timeout = s.num;
2201 break;
2202 case VHOST_GET_VRING_BUSYLOOP_TIMEOUT:
2203 s.index = idx;
2204 s.num = vq->busyloop_timeout;
2205 if (copy_to_user(argp, &s, sizeof(s)))
2206 r = -EFAULT;
2207 break;
2208 default:
2209 r = -ENOIOCTLCMD;
2210 }
2211
2212 if (pollstop && vq->handle_kick)
2213 vhost_poll_stop(&vq->poll);
2214
2215 if (!IS_ERR_OR_NULL(ctx))
2216 eventfd_ctx_put(ctx);
2217 if (filep)
2218 fput(filep);
2219
2220 if (pollstart && vq->handle_kick)
2221 r = vhost_poll_start(&vq->poll, vq->kick);
2222
2223 mutex_unlock(&vq->mutex);
2224
2225 if (pollstop && vq->handle_kick)
2226 vhost_poll_flush(&vq->poll);
2227 return r;
2228 }
2229 EXPORT_SYMBOL_GPL(vhost_vring_ioctl);
2230
2231 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled)
2232 {
2233 struct vhost_umem *niotlb, *oiotlb;
2234 int i;
2235
2236 niotlb = vhost_umem_alloc();
2237 if (!niotlb)
2238 return -ENOMEM;
2239
2240 oiotlb = d->iotlb;
2241 d->iotlb = niotlb;
2242
2243 for (i = 0; i < d->nvqs; ++i) {
2244 struct vhost_virtqueue *vq = d->vqs[i];
2245
2246 mutex_lock(&vq->mutex);
2247 vq->iotlb = niotlb;
2248 __vhost_vq_meta_reset(vq);
2249 mutex_unlock(&vq->mutex);
2250 }
2251
2252 vhost_umem_clean(oiotlb);
2253
2254 return 0;
2255 }
2256 EXPORT_SYMBOL_GPL(vhost_init_device_iotlb);
2257
2258 /* Caller must have device mutex */
2259 long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
2260 {
2261 struct eventfd_ctx *ctx;
2262 u64 p;
2263 long r;
2264 int i, fd;
2265
2266 /* If you are not the owner, you can become one */
2267 if (ioctl == VHOST_SET_OWNER) {
2268 r = vhost_dev_set_owner(d);
2269 goto done;
2270 }
2271
2272 /* You must be the owner to do anything else */
2273 r = vhost_dev_check_owner(d);
2274 if (r)
2275 goto done;
2276
2277 switch (ioctl) {
2278 case VHOST_SET_MEM_TABLE:
2279 r = vhost_set_memory(d, argp);
2280 break;
2281 case VHOST_SET_LOG_BASE:
2282 if (copy_from_user(&p, argp, sizeof p)) {
2283 r = -EFAULT;
2284 break;
2285 }
2286 if ((u64)(unsigned long)p != p) {
2287 r = -EFAULT;
2288 break;
2289 }
2290 for (i = 0; i < d->nvqs; ++i) {
2291 struct vhost_virtqueue *vq;
2292 void __user *base = (void __user *)(unsigned long)p;
2293 vq = d->vqs[i];
2294 mutex_lock(&vq->mutex);
2295 /* If ring is inactive, will check when it's enabled. */
2296 if (vq->private_data && !vq_log_access_ok(vq, base))
2297 r = -EFAULT;
2298 else
2299 vq->log_base = base;
2300 mutex_unlock(&vq->mutex);
2301 }
2302 break;
2303 case VHOST_SET_LOG_FD:
2304 r = get_user(fd, (int __user *)argp);
2305 if (r < 0)
2306 break;
2307 ctx = fd == -1 ? NULL : eventfd_ctx_fdget(fd);
2308 if (IS_ERR(ctx)) {
2309 r = PTR_ERR(ctx);
2310 break;
2311 }
2312 swap(ctx, d->log_ctx);
2313 for (i = 0; i < d->nvqs; ++i) {
2314 mutex_lock(&d->vqs[i]->mutex);
2315 d->vqs[i]->log_ctx = d->log_ctx;
2316 mutex_unlock(&d->vqs[i]->mutex);
2317 }
2318 if (ctx)
2319 eventfd_ctx_put(ctx);
2320 break;
2321 default:
2322 r = -ENOIOCTLCMD;
2323 break;
2324 }
2325 done:
2326 return r;
2327 }
2328 EXPORT_SYMBOL_GPL(vhost_dev_ioctl);
2329
2330 /* TODO: This is really inefficient. We need something like get_user()
2331 * (instruction directly accesses the data, with an exception table entry
2332 * returning -EFAULT). See Documentation/x86/exception-tables.rst.
2333 */
2334 static int set_bit_to_user(int nr, void __user *addr)
2335 {
2336 unsigned long log = (unsigned long)addr;
2337 struct page *page;
2338 void *base;
2339 int bit = nr + (log % PAGE_SIZE) * 8;
2340 int r;
2341
2342 r = get_user_pages_fast(log, 1, FOLL_WRITE, &page);
2343 if (r < 0)
2344 return r;
2345 BUG_ON(r != 1);
2346 base = kmap_atomic(page);
2347 set_bit(bit, base);
2348 kunmap_atomic(base);
2349 set_page_dirty_lock(page);
2350 put_page(page);
2351 return 0;
2352 }
2353
2354 static int log_write(void __user *log_base,
2355 u64 write_address, u64 write_length)
2356 {
2357 u64 write_page = write_address / VHOST_PAGE_SIZE;
2358 int r;
2359
2360 if (!write_length)
2361 return 0;
2362 write_length += write_address % VHOST_PAGE_SIZE;
2363 for (;;) {
2364 u64 base = (u64)(unsigned long)log_base;
2365 u64 log = base + write_page / 8;
2366 int bit = write_page % 8;
2367 if ((u64)(unsigned long)log != log)
2368 return -EFAULT;
2369 r = set_bit_to_user(bit, (void __user *)(unsigned long)log);
2370 if (r < 0)
2371 return r;
2372 if (write_length <= VHOST_PAGE_SIZE)
2373 break;
2374 write_length -= VHOST_PAGE_SIZE;
2375 write_page += 1;
2376 }
2377 return r;
2378 }
2379
2380 static int log_write_hva(struct vhost_virtqueue *vq, u64 hva, u64 len)
2381 {
2382 struct vhost_umem *umem = vq->umem;
2383 struct vhost_umem_node *u;
2384 u64 start, end, l, min;
2385 int r;
2386 bool hit = false;
2387
2388 while (len) {
2389 min = len;
2390 /* More than one GPAs can be mapped into a single HVA. So
2391 * iterate all possible umems here to be safe.
2392 */
2393 list_for_each_entry(u, &umem->umem_list, link) {
2394 if (u->userspace_addr > hva - 1 + len ||
2395 u->userspace_addr - 1 + u->size < hva)
2396 continue;
2397 start = max(u->userspace_addr, hva);
2398 end = min(u->userspace_addr - 1 + u->size,
2399 hva - 1 + len);
2400 l = end - start + 1;
2401 r = log_write(vq->log_base,
2402 u->start + start - u->userspace_addr,
2403 l);
2404 if (r < 0)
2405 return r;
2406 hit = true;
2407 min = min(l, min);
2408 }
2409
2410 if (!hit)
2411 return -EFAULT;
2412
2413 len -= min;
2414 hva += min;
2415 }
2416
2417 return 0;
2418 }
2419
2420 static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len)
2421 {
2422 struct iovec iov[64];
2423 int i, ret;
2424
2425 if (!vq->iotlb)
2426 return log_write(vq->log_base, vq->log_addr + used_offset, len);
2427
2428 ret = translate_desc(vq, (uintptr_t)vq->used + used_offset,
2429 len, iov, 64, VHOST_ACCESS_WO);
2430 if (ret < 0)
2431 return ret;
2432
2433 for (i = 0; i < ret; i++) {
2434 ret = log_write_hva(vq, (uintptr_t)iov[i].iov_base,
2435 iov[i].iov_len);
2436 if (ret)
2437 return ret;
2438 }
2439
2440 return 0;
2441 }
2442
2443 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
2444 unsigned int log_num, u64 len, struct iovec *iov, int count)
2445 {
2446 int i, r;
2447
2448 /* Make sure data written is seen before log. */
2449 smp_wmb();
2450
2451 if (vq->iotlb) {
2452 for (i = 0; i < count; i++) {
2453 r = log_write_hva(vq, (uintptr_t)iov[i].iov_base,
2454 iov[i].iov_len);
2455 if (r < 0)
2456 return r;
2457 }
2458 return 0;
2459 }
2460
2461 for (i = 0; i < log_num; ++i) {
2462 u64 l = min(log[i].len, len);
2463 r = log_write(vq->log_base, log[i].addr, l);
2464 if (r < 0)
2465 return r;
2466 len -= l;
2467 if (!len) {
2468 if (vq->log_ctx)
2469 eventfd_signal(vq->log_ctx, 1);
2470 return 0;
2471 }
2472 }
2473 /* Length written exceeds what we have stored. This is a bug. */
2474 BUG();
2475 return 0;
2476 }
2477 EXPORT_SYMBOL_GPL(vhost_log_write);
2478
2479 static int vhost_update_used_flags(struct vhost_virtqueue *vq)
2480 {
2481 void __user *used;
2482 if (vhost_put_used_flags(vq))
2483 return -EFAULT;
2484 if (unlikely(vq->log_used)) {
2485 /* Make sure the flag is seen before log. */
2486 smp_wmb();
2487 /* Log used flag write. */
2488 used = &vq->used->flags;
2489 log_used(vq, (used - (void __user *)vq->used),
2490 sizeof vq->used->flags);
2491 if (vq->log_ctx)
2492 eventfd_signal(vq->log_ctx, 1);
2493 }
2494 return 0;
2495 }
2496
2497 static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
2498 {
2499 if (vhost_put_avail_event(vq))
2500 return -EFAULT;
2501 if (unlikely(vq->log_used)) {
2502 void __user *used;
2503 /* Make sure the event is seen before log. */
2504 smp_wmb();
2505 /* Log avail event write */
2506 used = vhost_avail_event(vq);
2507 log_used(vq, (used - (void __user *)vq->used),
2508 sizeof *vhost_avail_event(vq));
2509 if (vq->log_ctx)
2510 eventfd_signal(vq->log_ctx, 1);
2511 }
2512 return 0;
2513 }
2514
2515 int vhost_vq_init_access(struct vhost_virtqueue *vq)
2516 {
2517 __virtio16 last_used_idx;
2518 int r;
2519 bool is_le = vq->is_le;
2520
2521 if (!vq->private_data)
2522 return 0;
2523
2524 vhost_init_is_le(vq);
2525
2526 r = vhost_update_used_flags(vq);
2527 if (r)
2528 goto err;
2529 vq->signalled_used_valid = false;
2530 if (!vq->iotlb &&
2531 !access_ok(&vq->used->idx, sizeof vq->used->idx)) {
2532 r = -EFAULT;
2533 goto err;
2534 }
2535 r = vhost_get_used_idx(vq, &last_used_idx);
2536 if (r) {
2537 vq_err(vq, "Can't access used idx at %p\n",
2538 &vq->used->idx);
2539 goto err;
2540 }
2541 vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx);
2542 return 0;
2543
2544 err:
2545 vq->is_le = is_le;
2546 return r;
2547 }
2548 EXPORT_SYMBOL_GPL(vhost_vq_init_access);
2549
2550 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
2551 struct iovec iov[], int iov_size, int access)
2552 {
2553 const struct vhost_umem_node *node;
2554 struct vhost_dev *dev = vq->dev;
2555 struct vhost_umem *umem = dev->iotlb ? dev->iotlb : dev->umem;
2556 struct iovec *_iov;
2557 u64 s = 0;
2558 int ret = 0;
2559
2560 while ((u64)len > s) {
2561 u64 size;
2562 if (unlikely(ret >= iov_size)) {
2563 ret = -ENOBUFS;
2564 break;
2565 }
2566
2567 node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
2568 addr, addr + len - 1);
2569 if (node == NULL || node->start > addr) {
2570 if (umem != dev->iotlb) {
2571 ret = -EFAULT;
2572 break;
2573 }
2574 ret = -EAGAIN;
2575 break;
2576 } else if (!(node->perm & access)) {
2577 ret = -EPERM;
2578 break;
2579 }
2580
2581 _iov = iov + ret;
2582 size = node->size - addr + node->start;
2583 _iov->iov_len = min((u64)len - s, size);
2584 _iov->iov_base = (void __user *)(unsigned long)
2585 (node->userspace_addr + addr - node->start);
2586 s += size;
2587 addr += size;
2588 ++ret;
2589 }
2590
2591 if (ret == -EAGAIN)
2592 vhost_iotlb_miss(vq, addr, access);
2593 return ret;
2594 }
2595
2596 /* Each buffer in the virtqueues is actually a chain of descriptors. This
2597 * function returns the next descriptor in the chain,
2598 * or -1U if we're at the end. */
2599 static unsigned next_desc(struct vhost_virtqueue *vq, struct vring_desc *desc)
2600 {
2601 unsigned int next;
2602
2603 /* If this descriptor says it doesn't chain, we're done. */
2604 if (!(desc->flags & cpu_to_vhost16(vq, VRING_DESC_F_NEXT)))
2605 return -1U;
2606
2607 /* Check they're not leading us off end of descriptors. */
2608 next = vhost16_to_cpu(vq, READ_ONCE(desc->next));
2609 return next;
2610 }
2611
2612 static int get_indirect(struct vhost_virtqueue *vq,
2613 struct iovec iov[], unsigned int iov_size,
2614 unsigned int *out_num, unsigned int *in_num,
2615 struct vhost_log *log, unsigned int *log_num,
2616 struct vring_desc *indirect)
2617 {
2618 struct vring_desc desc;
2619 unsigned int i = 0, count, found = 0;
2620 u32 len = vhost32_to_cpu(vq, indirect->len);
2621 struct iov_iter from;
2622 int ret, access;
2623
2624 /* Sanity check */
2625 if (unlikely(len % sizeof desc)) {
2626 vq_err(vq, "Invalid length in indirect descriptor: "
2627 "len 0x%llx not multiple of 0x%zx\n",
2628 (unsigned long long)len,
2629 sizeof desc);
2630 return -EINVAL;
2631 }
2632
2633 ret = translate_desc(vq, vhost64_to_cpu(vq, indirect->addr), len, vq->indirect,
2634 UIO_MAXIOV, VHOST_ACCESS_RO);
2635 if (unlikely(ret < 0)) {
2636 if (ret != -EAGAIN)
2637 vq_err(vq, "Translation failure %d in indirect.\n", ret);
2638 return ret;
2639 }
2640 iov_iter_init(&from, READ, vq->indirect, ret, len);
2641
2642 /* We will use the result as an address to read from, so most
2643 * architectures only need a compiler barrier here. */
2644 read_barrier_depends();
2645
2646 count = len / sizeof desc;
2647 /* Buffers are chained via a 16 bit next field, so
2648 * we can have at most 2^16 of these. */
2649 if (unlikely(count > USHRT_MAX + 1)) {
2650 vq_err(vq, "Indirect buffer length too big: %d\n",
2651 indirect->len);
2652 return -E2BIG;
2653 }
2654
2655 do {
2656 unsigned iov_count = *in_num + *out_num;
2657 if (unlikely(++found > count)) {
2658 vq_err(vq, "Loop detected: last one at %u "
2659 "indirect size %u\n",
2660 i, count);
2661 return -EINVAL;
2662 }
2663 if (unlikely(!copy_from_iter_full(&desc, sizeof(desc), &from))) {
2664 vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
2665 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
2666 return -EINVAL;
2667 }
2668 if (unlikely(desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT))) {
2669 vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n",
2670 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
2671 return -EINVAL;
2672 }
2673
2674 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
2675 access = VHOST_ACCESS_WO;
2676 else
2677 access = VHOST_ACCESS_RO;
2678
2679 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
2680 vhost32_to_cpu(vq, desc.len), iov + iov_count,
2681 iov_size - iov_count, access);
2682 if (unlikely(ret < 0)) {
2683 if (ret != -EAGAIN)
2684 vq_err(vq, "Translation failure %d indirect idx %d\n",
2685 ret, i);
2686 return ret;
2687 }
2688 /* If this is an input descriptor, increment that count. */
2689 if (access == VHOST_ACCESS_WO) {
2690 *in_num += ret;
2691 if (unlikely(log)) {
2692 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
2693 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
2694 ++*log_num;
2695 }
2696 } else {
2697 /* If it's an output descriptor, they're all supposed
2698 * to come before any input descriptors. */
2699 if (unlikely(*in_num)) {
2700 vq_err(vq, "Indirect descriptor "
2701 "has out after in: idx %d\n", i);
2702 return -EINVAL;
2703 }
2704 *out_num += ret;
2705 }
2706 } while ((i = next_desc(vq, &desc)) != -1);
2707 return 0;
2708 }
2709
2710 /* This looks in the virtqueue and for the first available buffer, and converts
2711 * it to an iovec for convenient access. Since descriptors consist of some
2712 * number of output then some number of input descriptors, it's actually two
2713 * iovecs, but we pack them into one and note how many of each there were.
2714 *
2715 * This function returns the descriptor number found, or vq->num (which is
2716 * never a valid descriptor number) if none was found. A negative code is
2717 * returned on error. */
2718 int vhost_get_vq_desc(struct vhost_virtqueue *vq,
2719 struct iovec iov[], unsigned int iov_size,
2720 unsigned int *out_num, unsigned int *in_num,
2721 struct vhost_log *log, unsigned int *log_num)
2722 {
2723 struct vring_desc desc;
2724 unsigned int i, head, found = 0;
2725 u16 last_avail_idx;
2726 __virtio16 avail_idx;
2727 __virtio16 ring_head;
2728 int ret, access;
2729
2730 /* Check it isn't doing very strange things with descriptor numbers. */
2731 last_avail_idx = vq->last_avail_idx;
2732
2733 if (vq->avail_idx == vq->last_avail_idx) {
2734 if (unlikely(vhost_get_avail_idx(vq, &avail_idx))) {
2735 vq_err(vq, "Failed to access avail idx at %p\n",
2736 &vq->avail->idx);
2737 return -EFAULT;
2738 }
2739 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2740
2741 if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) {
2742 vq_err(vq, "Guest moved used index from %u to %u",
2743 last_avail_idx, vq->avail_idx);
2744 return -EFAULT;
2745 }
2746
2747 /* If there's nothing new since last we looked, return
2748 * invalid.
2749 */
2750 if (vq->avail_idx == last_avail_idx)
2751 return vq->num;
2752
2753 /* Only get avail ring entries after they have been
2754 * exposed by guest.
2755 */
2756 smp_rmb();
2757 }
2758
2759 /* Grab the next descriptor number they're advertising, and increment
2760 * the index we've seen. */
2761 if (unlikely(vhost_get_avail_head(vq, &ring_head, last_avail_idx))) {
2762 vq_err(vq, "Failed to read head: idx %d address %p\n",
2763 last_avail_idx,
2764 &vq->avail->ring[last_avail_idx % vq->num]);
2765 return -EFAULT;
2766 }
2767
2768 head = vhost16_to_cpu(vq, ring_head);
2769
2770 /* If their number is silly, that's an error. */
2771 if (unlikely(head >= vq->num)) {
2772 vq_err(vq, "Guest says index %u > %u is available",
2773 head, vq->num);
2774 return -EINVAL;
2775 }
2776
2777 /* When we start there are none of either input nor output. */
2778 *out_num = *in_num = 0;
2779 if (unlikely(log))
2780 *log_num = 0;
2781
2782 i = head;
2783 do {
2784 unsigned iov_count = *in_num + *out_num;
2785 if (unlikely(i >= vq->num)) {
2786 vq_err(vq, "Desc index is %u > %u, head = %u",
2787 i, vq->num, head);
2788 return -EINVAL;
2789 }
2790 if (unlikely(++found > vq->num)) {
2791 vq_err(vq, "Loop detected: last one at %u "
2792 "vq size %u head %u\n",
2793 i, vq->num, head);
2794 return -EINVAL;
2795 }
2796 ret = vhost_get_desc(vq, &desc, i);
2797 if (unlikely(ret)) {
2798 vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
2799 i, vq->desc + i);
2800 return -EFAULT;
2801 }
2802 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT)) {
2803 ret = get_indirect(vq, iov, iov_size,
2804 out_num, in_num,
2805 log, log_num, &desc);
2806 if (unlikely(ret < 0)) {
2807 if (ret != -EAGAIN)
2808 vq_err(vq, "Failure detected "
2809 "in indirect descriptor at idx %d\n", i);
2810 return ret;
2811 }
2812 continue;
2813 }
2814
2815 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
2816 access = VHOST_ACCESS_WO;
2817 else
2818 access = VHOST_ACCESS_RO;
2819 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
2820 vhost32_to_cpu(vq, desc.len), iov + iov_count,
2821 iov_size - iov_count, access);
2822 if (unlikely(ret < 0)) {
2823 if (ret != -EAGAIN)
2824 vq_err(vq, "Translation failure %d descriptor idx %d\n",
2825 ret, i);
2826 return ret;
2827 }
2828 if (access == VHOST_ACCESS_WO) {
2829 /* If this is an input descriptor,
2830 * increment that count. */
2831 *in_num += ret;
2832 if (unlikely(log)) {
2833 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
2834 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
2835 ++*log_num;
2836 }
2837 } else {
2838 /* If it's an output descriptor, they're all supposed
2839 * to come before any input descriptors. */
2840 if (unlikely(*in_num)) {
2841 vq_err(vq, "Descriptor has out after in: "
2842 "idx %d\n", i);
2843 return -EINVAL;
2844 }
2845 *out_num += ret;
2846 }
2847 } while ((i = next_desc(vq, &desc)) != -1);
2848
2849 /* On success, increment avail index. */
2850 vq->last_avail_idx++;
2851
2852 /* Assume notifications from guest are disabled at this point,
2853 * if they aren't we would need to update avail_event index. */
2854 BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY));
2855 return head;
2856 }
2857 EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
2858
2859 /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
2860 void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n)
2861 {
2862 vq->last_avail_idx -= n;
2863 }
2864 EXPORT_SYMBOL_GPL(vhost_discard_vq_desc);
2865
2866 /* After we've used one of their buffers, we tell them about it. We'll then
2867 * want to notify the guest, using eventfd. */
2868 int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
2869 {
2870 struct vring_used_elem heads = {
2871 cpu_to_vhost32(vq, head),
2872 cpu_to_vhost32(vq, len)
2873 };
2874
2875 return vhost_add_used_n(vq, &heads, 1);
2876 }
2877 EXPORT_SYMBOL_GPL(vhost_add_used);
2878
2879 static int __vhost_add_used_n(struct vhost_virtqueue *vq,
2880 struct vring_used_elem *heads,
2881 unsigned count)
2882 {
2883 struct vring_used_elem __user *used;
2884 u16 old, new;
2885 int start;
2886
2887 start = vq->last_used_idx & (vq->num - 1);
2888 used = vq->used->ring + start;
2889 if (vhost_put_used(vq, heads, start, count)) {
2890 vq_err(vq, "Failed to write used");
2891 return -EFAULT;
2892 }
2893 if (unlikely(vq->log_used)) {
2894 /* Make sure data is seen before log. */
2895 smp_wmb();
2896 /* Log used ring entry write. */
2897 log_used(vq, ((void __user *)used - (void __user *)vq->used),
2898 count * sizeof *used);
2899 }
2900 old = vq->last_used_idx;
2901 new = (vq->last_used_idx += count);
2902 /* If the driver never bothers to signal in a very long while,
2903 * used index might wrap around. If that happens, invalidate
2904 * signalled_used index we stored. TODO: make sure driver
2905 * signals at least once in 2^16 and remove this. */
2906 if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old)))
2907 vq->signalled_used_valid = false;
2908 return 0;
2909 }
2910
2911 /* After we've used one of their buffers, we tell them about it. We'll then
2912 * want to notify the guest, using eventfd. */
2913 int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
2914 unsigned count)
2915 {
2916 int start, n, r;
2917
2918 start = vq->last_used_idx & (vq->num - 1);
2919 n = vq->num - start;
2920 if (n < count) {
2921 r = __vhost_add_used_n(vq, heads, n);
2922 if (r < 0)
2923 return r;
2924 heads += n;
2925 count -= n;
2926 }
2927 r = __vhost_add_used_n(vq, heads, count);
2928
2929 /* Make sure buffer is written before we update index. */
2930 smp_wmb();
2931 if (vhost_put_used_idx(vq)) {
2932 vq_err(vq, "Failed to increment used idx");
2933 return -EFAULT;
2934 }
2935 if (unlikely(vq->log_used)) {
2936 /* Make sure used idx is seen before log. */
2937 smp_wmb();
2938 /* Log used index update. */
2939 log_used(vq, offsetof(struct vring_used, idx),
2940 sizeof vq->used->idx);
2941 if (vq->log_ctx)
2942 eventfd_signal(vq->log_ctx, 1);
2943 }
2944 return r;
2945 }
2946 EXPORT_SYMBOL_GPL(vhost_add_used_n);
2947
2948 static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2949 {
2950 __u16 old, new;
2951 __virtio16 event;
2952 bool v;
2953 /* Flush out used index updates. This is paired
2954 * with the barrier that the Guest executes when enabling
2955 * interrupts. */
2956 smp_mb();
2957
2958 if (vhost_has_feature(vq, VIRTIO_F_NOTIFY_ON_EMPTY) &&
2959 unlikely(vq->avail_idx == vq->last_avail_idx))
2960 return true;
2961
2962 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2963 __virtio16 flags;
2964 if (vhost_get_avail_flags(vq, &flags)) {
2965 vq_err(vq, "Failed to get flags");
2966 return true;
2967 }
2968 return !(flags & cpu_to_vhost16(vq, VRING_AVAIL_F_NO_INTERRUPT));
2969 }
2970 old = vq->signalled_used;
2971 v = vq->signalled_used_valid;
2972 new = vq->signalled_used = vq->last_used_idx;
2973 vq->signalled_used_valid = true;
2974
2975 if (unlikely(!v))
2976 return true;
2977
2978 if (vhost_get_used_event(vq, &event)) {
2979 vq_err(vq, "Failed to get used event idx");
2980 return true;
2981 }
2982 return vring_need_event(vhost16_to_cpu(vq, event), new, old);
2983 }
2984
2985 /* This actually signals the guest, using eventfd. */
2986 void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2987 {
2988 /* Signal the Guest tell them we used something up. */
2989 if (vq->call_ctx && vhost_notify(dev, vq))
2990 eventfd_signal(vq->call_ctx, 1);
2991 }
2992 EXPORT_SYMBOL_GPL(vhost_signal);
2993
2994 /* And here's the combo meal deal. Supersize me! */
2995 void vhost_add_used_and_signal(struct vhost_dev *dev,
2996 struct vhost_virtqueue *vq,
2997 unsigned int head, int len)
2998 {
2999 vhost_add_used(vq, head, len);
3000 vhost_signal(dev, vq);
3001 }
3002 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal);
3003
3004 /* multi-buffer version of vhost_add_used_and_signal */
3005 void vhost_add_used_and_signal_n(struct vhost_dev *dev,
3006 struct vhost_virtqueue *vq,
3007 struct vring_used_elem *heads, unsigned count)
3008 {
3009 vhost_add_used_n(vq, heads, count);
3010 vhost_signal(dev, vq);
3011 }
3012 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
3013
3014 /* return true if we're sure that avaiable ring is empty */
3015 bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
3016 {
3017 __virtio16 avail_idx;
3018 int r;
3019
3020 if (vq->avail_idx != vq->last_avail_idx)
3021 return false;
3022
3023 r = vhost_get_avail_idx(vq, &avail_idx);
3024 if (unlikely(r))
3025 return false;
3026 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
3027
3028 return vq->avail_idx == vq->last_avail_idx;
3029 }
3030 EXPORT_SYMBOL_GPL(vhost_vq_avail_empty);
3031
3032 /* OK, now we need to know about added descriptors. */
3033 bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
3034 {
3035 __virtio16 avail_idx;
3036 int r;
3037
3038 if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
3039 return false;
3040 vq->used_flags &= ~VRING_USED_F_NO_NOTIFY;
3041 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
3042 r = vhost_update_used_flags(vq);
3043 if (r) {
3044 vq_err(vq, "Failed to enable notification at %p: %d\n",
3045 &vq->used->flags, r);
3046 return false;
3047 }
3048 } else {
3049 r = vhost_update_avail_event(vq, vq->avail_idx);
3050 if (r) {
3051 vq_err(vq, "Failed to update avail event index at %p: %d\n",
3052 vhost_avail_event(vq), r);
3053 return false;
3054 }
3055 }
3056 /* They could have slipped one in as we were doing that: make
3057 * sure it's written, then check again. */
3058 smp_mb();
3059 r = vhost_get_avail_idx(vq, &avail_idx);
3060 if (r) {
3061 vq_err(vq, "Failed to check avail idx at %p: %d\n",
3062 &vq->avail->idx, r);
3063 return false;
3064 }
3065
3066 return vhost16_to_cpu(vq, avail_idx) != vq->avail_idx;
3067 }
3068 EXPORT_SYMBOL_GPL(vhost_enable_notify);
3069
3070 /* We don't need to be notified again. */
3071 void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
3072 {
3073 int r;
3074
3075 if (vq->used_flags & VRING_USED_F_NO_NOTIFY)
3076 return;
3077 vq->used_flags |= VRING_USED_F_NO_NOTIFY;
3078 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
3079 r = vhost_update_used_flags(vq);
3080 if (r)
3081 vq_err(vq, "Failed to enable notification at %p: %d\n",
3082 &vq->used->flags, r);
3083 }
3084 }
3085 EXPORT_SYMBOL_GPL(vhost_disable_notify);
3086
3087 /* Create a new message. */
3088 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type)
3089 {
3090 struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL);
3091 if (!node)
3092 return NULL;
3093
3094 /* Make sure all padding within the structure is initialized. */
3095 memset(&node->msg, 0, sizeof node->msg);
3096 node->vq = vq;
3097 node->msg.type = type;
3098 return node;
3099 }
3100 EXPORT_SYMBOL_GPL(vhost_new_msg);
3101
3102 void vhost_enqueue_msg(struct vhost_dev *dev, struct list_head *head,
3103 struct vhost_msg_node *node)
3104 {
3105 spin_lock(&dev->iotlb_lock);
3106 list_add_tail(&node->node, head);
3107 spin_unlock(&dev->iotlb_lock);
3108
3109 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
3110 }
3111 EXPORT_SYMBOL_GPL(vhost_enqueue_msg);
3112
3113 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
3114 struct list_head *head)
3115 {
3116 struct vhost_msg_node *node = NULL;
3117
3118 spin_lock(&dev->iotlb_lock);
3119 if (!list_empty(head)) {
3120 node = list_first_entry(head, struct vhost_msg_node,
3121 node);
3122 list_del(&node->node);
3123 }
3124 spin_unlock(&dev->iotlb_lock);
3125
3126 return node;
3127 }
3128 EXPORT_SYMBOL_GPL(vhost_dequeue_msg);
3129
3130
3131 static int __init vhost_init(void)
3132 {
3133 return 0;
3134 }
3135
3136 static void __exit vhost_exit(void)
3137 {
3138 }
3139
3140 module_init(vhost_init);
3141 module_exit(vhost_exit);
3142
3143 MODULE_VERSION("0.0.1");
3144 MODULE_LICENSE("GPL v2");
3145 MODULE_AUTHOR("Michael S. Tsirkin");
3146 MODULE_DESCRIPTION("Host kernel accelerator for virtio");
Linux with added FPC-III support