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Merge tag 'pm-4.19-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
[linux-2.6/btrfs-unstable.git] / drivers / vhost / vhost.c
blobb13c6b4b2c665a332a40aeada1eaa1e421d9a4aa
1 /* Copyright (C) 2009 Red Hat, Inc.
2 * Copyright (C) 2006 Rusty Russell IBM Corporation
3 *
4 * Author: Michael S. Tsirkin <mst@redhat.com>
5 *
6 * Inspiration, some code, and most witty comments come from
7 * Documentation/virtual/lguest/lguest.c, by Rusty Russell
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2.
10 *
11 * Generic code for virtio server in host kernel.
12 */
13
14 #include <linux/eventfd.h>
15 #include <linux/vhost.h>
16 #include <linux/uio.h>
17 #include <linux/mm.h>
18 #include <linux/mmu_context.h>
19 #include <linux/miscdevice.h>
20 #include <linux/mutex.h>
21 #include <linux/poll.h>
22 #include <linux/file.h>
23 #include <linux/highmem.h>
24 #include <linux/slab.h>
25 #include <linux/vmalloc.h>
26 #include <linux/kthread.h>
27 #include <linux/cgroup.h>
28 #include <linux/module.h>
29 #include <linux/sort.h>
30 #include <linux/sched/mm.h>
31 #include <linux/sched/signal.h>
32 #include <linux/interval_tree_generic.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 static void vhost_vq_reset(struct vhost_dev *dev,
302 struct vhost_virtqueue *vq)
303 {
304 vq->num = 1;
305 vq->desc = NULL;
306 vq->avail = NULL;
307 vq->used = NULL;
308 vq->last_avail_idx = 0;
309 vq->avail_idx = 0;
310 vq->last_used_idx = 0;
311 vq->signalled_used = 0;
312 vq->signalled_used_valid = false;
313 vq->used_flags = 0;
314 vq->log_used = false;
315 vq->log_addr = -1ull;
316 vq->private_data = NULL;
317 vq->acked_features = 0;
318 vq->acked_backend_features = 0;
319 vq->log_base = NULL;
320 vq->error_ctx = NULL;
321 vq->kick = NULL;
322 vq->call_ctx = NULL;
323 vq->log_ctx = NULL;
324 vhost_reset_is_le(vq);
325 vhost_disable_cross_endian(vq);
326 vq->busyloop_timeout = 0;
327 vq->umem = NULL;
328 vq->iotlb = NULL;
329 __vhost_vq_meta_reset(vq);
330 }
331
332 static int vhost_worker(void *data)
333 {
334 struct vhost_dev *dev = data;
335 struct vhost_work *work, *work_next;
336 struct llist_node *node;
337 mm_segment_t oldfs = get_fs();
338
339 set_fs(USER_DS);
340 use_mm(dev->mm);
341
342 for (;;) {
343 /* mb paired w/ kthread_stop */
344 set_current_state(TASK_INTERRUPTIBLE);
345
346 if (kthread_should_stop()) {
347 __set_current_state(TASK_RUNNING);
348 break;
349 }
350
351 node = llist_del_all(&dev->work_list);
352 if (!node)
353 schedule();
354
355 node = llist_reverse_order(node);
356 /* make sure flag is seen after deletion */
357 smp_wmb();
358 llist_for_each_entry_safe(work, work_next, node, node) {
359 clear_bit(VHOST_WORK_QUEUED, &work->flags);
360 __set_current_state(TASK_RUNNING);
361 work->fn(work);
362 if (need_resched())
363 schedule();
364 }
365 }
366 unuse_mm(dev->mm);
367 set_fs(oldfs);
368 return 0;
369 }
370
371 static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq)
372 {
373 kfree(vq->indirect);
374 vq->indirect = NULL;
375 kfree(vq->log);
376 vq->log = NULL;
377 kfree(vq->heads);
378 vq->heads = NULL;
379 }
380
381 /* Helper to allocate iovec buffers for all vqs. */
382 static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
383 {
384 struct vhost_virtqueue *vq;
385 int i;
386
387 for (i = 0; i < dev->nvqs; ++i) {
388 vq = dev->vqs[i];
389 vq->indirect = kmalloc_array(UIO_MAXIOV,
390 sizeof(*vq->indirect),
391 GFP_KERNEL);
392 vq->log = kmalloc_array(UIO_MAXIOV, sizeof(*vq->log),
393 GFP_KERNEL);
394 vq->heads = kmalloc_array(UIO_MAXIOV, sizeof(*vq->heads),
395 GFP_KERNEL);
396 if (!vq->indirect || !vq->log || !vq->heads)
397 goto err_nomem;
398 }
399 return 0;
400
401 err_nomem:
402 for (; i >= 0; --i)
403 vhost_vq_free_iovecs(dev->vqs[i]);
404 return -ENOMEM;
405 }
406
407 static void vhost_dev_free_iovecs(struct vhost_dev *dev)
408 {
409 int i;
410
411 for (i = 0; i < dev->nvqs; ++i)
412 vhost_vq_free_iovecs(dev->vqs[i]);
413 }
414
415 void vhost_dev_init(struct vhost_dev *dev,
416 struct vhost_virtqueue **vqs, int nvqs)
417 {
418 struct vhost_virtqueue *vq;
419 int i;
420
421 dev->vqs = vqs;
422 dev->nvqs = nvqs;
423 mutex_init(&dev->mutex);
424 dev->log_ctx = NULL;
425 dev->umem = NULL;
426 dev->iotlb = NULL;
427 dev->mm = NULL;
428 dev->worker = NULL;
429 init_llist_head(&dev->work_list);
430 init_waitqueue_head(&dev->wait);
431 INIT_LIST_HEAD(&dev->read_list);
432 INIT_LIST_HEAD(&dev->pending_list);
433 spin_lock_init(&dev->iotlb_lock);
434
435
436 for (i = 0; i < dev->nvqs; ++i) {
437 vq = dev->vqs[i];
438 vq->log = NULL;
439 vq->indirect = NULL;
440 vq->heads = NULL;
441 vq->dev = dev;
442 mutex_init(&vq->mutex);
443 vhost_vq_reset(dev, vq);
444 if (vq->handle_kick)
445 vhost_poll_init(&vq->poll, vq->handle_kick,
446 EPOLLIN, dev);
447 }
448 }
449 EXPORT_SYMBOL_GPL(vhost_dev_init);
450
451 /* Caller should have device mutex */
452 long vhost_dev_check_owner(struct vhost_dev *dev)
453 {
454 /* Are you the owner? If not, I don't think you mean to do that */
455 return dev->mm == current->mm ? 0 : -EPERM;
456 }
457 EXPORT_SYMBOL_GPL(vhost_dev_check_owner);
458
459 struct vhost_attach_cgroups_struct {
460 struct vhost_work work;
461 struct task_struct *owner;
462 int ret;
463 };
464
465 static void vhost_attach_cgroups_work(struct vhost_work *work)
466 {
467 struct vhost_attach_cgroups_struct *s;
468
469 s = container_of(work, struct vhost_attach_cgroups_struct, work);
470 s->ret = cgroup_attach_task_all(s->owner, current);
471 }
472
473 static int vhost_attach_cgroups(struct vhost_dev *dev)
474 {
475 struct vhost_attach_cgroups_struct attach;
476
477 attach.owner = current;
478 vhost_work_init(&attach.work, vhost_attach_cgroups_work);
479 vhost_work_queue(dev, &attach.work);
480 vhost_work_flush(dev, &attach.work);
481 return attach.ret;
482 }
483
484 /* Caller should have device mutex */
485 bool vhost_dev_has_owner(struct vhost_dev *dev)
486 {
487 return dev->mm;
488 }
489 EXPORT_SYMBOL_GPL(vhost_dev_has_owner);
490
491 /* Caller should have device mutex */
492 long vhost_dev_set_owner(struct vhost_dev *dev)
493 {
494 struct task_struct *worker;
495 int err;
496
497 /* Is there an owner already? */
498 if (vhost_dev_has_owner(dev)) {
499 err = -EBUSY;
500 goto err_mm;
501 }
502
503 /* No owner, become one */
504 dev->mm = get_task_mm(current);
505 worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid);
506 if (IS_ERR(worker)) {
507 err = PTR_ERR(worker);
508 goto err_worker;
509 }
510
511 dev->worker = worker;
512 wake_up_process(worker); /* avoid contributing to loadavg */
513
514 err = vhost_attach_cgroups(dev);
515 if (err)
516 goto err_cgroup;
517
518 err = vhost_dev_alloc_iovecs(dev);
519 if (err)
520 goto err_cgroup;
521
522 return 0;
523 err_cgroup:
524 kthread_stop(worker);
525 dev->worker = NULL;
526 err_worker:
527 if (dev->mm)
528 mmput(dev->mm);
529 dev->mm = NULL;
530 err_mm:
531 return err;
532 }
533 EXPORT_SYMBOL_GPL(vhost_dev_set_owner);
534
535 struct vhost_umem *vhost_dev_reset_owner_prepare(void)
536 {
537 return kvzalloc(sizeof(struct vhost_umem), GFP_KERNEL);
538 }
539 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare);
540
541 /* Caller should have device mutex */
542 void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_umem *umem)
543 {
544 int i;
545
546 vhost_dev_cleanup(dev);
547
548 /* Restore memory to default empty mapping. */
549 INIT_LIST_HEAD(&umem->umem_list);
550 dev->umem = umem;
551 /* We don't need VQ locks below since vhost_dev_cleanup makes sure
552 * VQs aren't running.
553 */
554 for (i = 0; i < dev->nvqs; ++i)
555 dev->vqs[i]->umem = umem;
556 }
557 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner);
558
559 void vhost_dev_stop(struct vhost_dev *dev)
560 {
561 int i;
562
563 for (i = 0; i < dev->nvqs; ++i) {
564 if (dev->vqs[i]->kick && dev->vqs[i]->handle_kick) {
565 vhost_poll_stop(&dev->vqs[i]->poll);
566 vhost_poll_flush(&dev->vqs[i]->poll);
567 }
568 }
569 }
570 EXPORT_SYMBOL_GPL(vhost_dev_stop);
571
572 static void vhost_umem_free(struct vhost_umem *umem,
573 struct vhost_umem_node *node)
574 {
575 vhost_umem_interval_tree_remove(node, &umem->umem_tree);
576 list_del(&node->link);
577 kfree(node);
578 umem->numem--;
579 }
580
581 static void vhost_umem_clean(struct vhost_umem *umem)
582 {
583 struct vhost_umem_node *node, *tmp;
584
585 if (!umem)
586 return;
587
588 list_for_each_entry_safe(node, tmp, &umem->umem_list, link)
589 vhost_umem_free(umem, node);
590
591 kvfree(umem);
592 }
593
594 static void vhost_clear_msg(struct vhost_dev *dev)
595 {
596 struct vhost_msg_node *node, *n;
597
598 spin_lock(&dev->iotlb_lock);
599
600 list_for_each_entry_safe(node, n, &dev->read_list, node) {
601 list_del(&node->node);
602 kfree(node);
603 }
604
605 list_for_each_entry_safe(node, n, &dev->pending_list, node) {
606 list_del(&node->node);
607 kfree(node);
608 }
609
610 spin_unlock(&dev->iotlb_lock);
611 }
612
613 void vhost_dev_cleanup(struct vhost_dev *dev)
614 {
615 int i;
616
617 for (i = 0; i < dev->nvqs; ++i) {
618 if (dev->vqs[i]->error_ctx)
619 eventfd_ctx_put(dev->vqs[i]->error_ctx);
620 if (dev->vqs[i]->kick)
621 fput(dev->vqs[i]->kick);
622 if (dev->vqs[i]->call_ctx)
623 eventfd_ctx_put(dev->vqs[i]->call_ctx);
624 vhost_vq_reset(dev, dev->vqs[i]);
625 }
626 vhost_dev_free_iovecs(dev);
627 if (dev->log_ctx)
628 eventfd_ctx_put(dev->log_ctx);
629 dev->log_ctx = NULL;
630 /* No one will access memory at this point */
631 vhost_umem_clean(dev->umem);
632 dev->umem = NULL;
633 vhost_umem_clean(dev->iotlb);
634 dev->iotlb = NULL;
635 vhost_clear_msg(dev);
636 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
637 WARN_ON(!llist_empty(&dev->work_list));
638 if (dev->worker) {
639 kthread_stop(dev->worker);
640 dev->worker = NULL;
641 }
642 if (dev->mm)
643 mmput(dev->mm);
644 dev->mm = NULL;
645 }
646 EXPORT_SYMBOL_GPL(vhost_dev_cleanup);
647
648 static bool log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
649 {
650 u64 a = addr / VHOST_PAGE_SIZE / 8;
651
652 /* Make sure 64 bit math will not overflow. */
653 if (a > ULONG_MAX - (unsigned long)log_base ||
654 a + (unsigned long)log_base > ULONG_MAX)
655 return false;
656
657 return access_ok(VERIFY_WRITE, log_base + a,
658 (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8);
659 }
660
661 static bool vhost_overflow(u64 uaddr, u64 size)
662 {
663 /* Make sure 64 bit math will not overflow. */
664 return uaddr > ULONG_MAX || size > ULONG_MAX || uaddr > ULONG_MAX - size;
665 }
666
667 /* Caller should have vq mutex and device mutex. */
668 static bool vq_memory_access_ok(void __user *log_base, struct vhost_umem *umem,
669 int log_all)
670 {
671 struct vhost_umem_node *node;
672
673 if (!umem)
674 return false;
675
676 list_for_each_entry(node, &umem->umem_list, link) {
677 unsigned long a = node->userspace_addr;
678
679 if (vhost_overflow(node->userspace_addr, node->size))
680 return false;
681
682
683 if (!access_ok(VERIFY_WRITE, (void __user *)a,
684 node->size))
685 return false;
686 else if (log_all && !log_access_ok(log_base,
687 node->start,
688 node->size))
689 return false;
690 }
691 return true;
692 }
693
694 static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq,
695 u64 addr, unsigned int size,
696 int type)
697 {
698 const struct vhost_umem_node *node = vq->meta_iotlb[type];
699
700 if (!node)
701 return NULL;
702
703 return (void *)(uintptr_t)(node->userspace_addr + addr - node->start);
704 }
705
706 /* Can we switch to this memory table? */
707 /* Caller should have device mutex but not vq mutex */
708 static bool memory_access_ok(struct vhost_dev *d, struct vhost_umem *umem,
709 int log_all)
710 {
711 int i;
712
713 for (i = 0; i < d->nvqs; ++i) {
714 bool ok;
715 bool log;
716
717 mutex_lock(&d->vqs[i]->mutex);
718 log = log_all || vhost_has_feature(d->vqs[i], VHOST_F_LOG_ALL);
719 /* If ring is inactive, will check when it's enabled. */
720 if (d->vqs[i]->private_data)
721 ok = vq_memory_access_ok(d->vqs[i]->log_base,
722 umem, log);
723 else
724 ok = true;
725 mutex_unlock(&d->vqs[i]->mutex);
726 if (!ok)
727 return false;
728 }
729 return true;
730 }
731
732 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
733 struct iovec iov[], int iov_size, int access);
734
735 static int vhost_copy_to_user(struct vhost_virtqueue *vq, void __user *to,
736 const void *from, unsigned size)
737 {
738 int ret;
739
740 if (!vq->iotlb)
741 return __copy_to_user(to, from, size);
742 else {
743 /* This function should be called after iotlb
744 * prefetch, which means we're sure that all vq
745 * could be access through iotlb. So -EAGAIN should
746 * not happen in this case.
747 */
748 struct iov_iter t;
749 void __user *uaddr = vhost_vq_meta_fetch(vq,
750 (u64)(uintptr_t)to, size,
751 VHOST_ADDR_USED);
752
753 if (uaddr)
754 return __copy_to_user(uaddr, from, size);
755
756 ret = translate_desc(vq, (u64)(uintptr_t)to, size, vq->iotlb_iov,
757 ARRAY_SIZE(vq->iotlb_iov),
758 VHOST_ACCESS_WO);
759 if (ret < 0)
760 goto out;
761 iov_iter_init(&t, WRITE, vq->iotlb_iov, ret, size);
762 ret = copy_to_iter(from, size, &t);
763 if (ret == size)
764 ret = 0;
765 }
766 out:
767 return ret;
768 }
769
770 static int vhost_copy_from_user(struct vhost_virtqueue *vq, void *to,
771 void __user *from, unsigned size)
772 {
773 int ret;
774
775 if (!vq->iotlb)
776 return __copy_from_user(to, from, size);
777 else {
778 /* This function should be called after iotlb
779 * prefetch, which means we're sure that vq
780 * could be access through iotlb. So -EAGAIN should
781 * not happen in this case.
782 */
783 void __user *uaddr = vhost_vq_meta_fetch(vq,
784 (u64)(uintptr_t)from, size,
785 VHOST_ADDR_DESC);
786 struct iov_iter f;
787
788 if (uaddr)
789 return __copy_from_user(to, uaddr, size);
790
791 ret = translate_desc(vq, (u64)(uintptr_t)from, size, vq->iotlb_iov,
792 ARRAY_SIZE(vq->iotlb_iov),
793 VHOST_ACCESS_RO);
794 if (ret < 0) {
795 vq_err(vq, "IOTLB translation failure: uaddr "
796 "%p size 0x%llx\n", from,
797 (unsigned long long) size);
798 goto out;
799 }
800 iov_iter_init(&f, READ, vq->iotlb_iov, ret, size);
801 ret = copy_from_iter(to, size, &f);
802 if (ret == size)
803 ret = 0;
804 }
805
806 out:
807 return ret;
808 }
809
810 static void __user *__vhost_get_user_slow(struct vhost_virtqueue *vq,
811 void __user *addr, unsigned int size,
812 int type)
813 {
814 int ret;
815
816 ret = translate_desc(vq, (u64)(uintptr_t)addr, size, vq->iotlb_iov,
817 ARRAY_SIZE(vq->iotlb_iov),
818 VHOST_ACCESS_RO);
819 if (ret < 0) {
820 vq_err(vq, "IOTLB translation failure: uaddr "
821 "%p size 0x%llx\n", addr,
822 (unsigned long long) size);
823 return NULL;
824 }
825
826 if (ret != 1 || vq->iotlb_iov[0].iov_len != size) {
827 vq_err(vq, "Non atomic userspace memory access: uaddr "
828 "%p size 0x%llx\n", addr,
829 (unsigned long long) size);
830 return NULL;
831 }
832
833 return vq->iotlb_iov[0].iov_base;
834 }
835
836 /* This function should be called after iotlb
837 * prefetch, which means we're sure that vq
838 * could be access through iotlb. So -EAGAIN should
839 * not happen in this case.
840 */
841 static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq,
842 void *addr, unsigned int size,
843 int type)
844 {
845 void __user *uaddr = vhost_vq_meta_fetch(vq,
846 (u64)(uintptr_t)addr, size, type);
847 if (uaddr)
848 return uaddr;
849
850 return __vhost_get_user_slow(vq, addr, size, type);
851 }
852
853 #define vhost_put_user(vq, x, ptr) \
854 ({ \
855 int ret = -EFAULT; \
856 if (!vq->iotlb) { \
857 ret = __put_user(x, ptr); \
858 } else { \
859 __typeof__(ptr) to = \
860 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
861 sizeof(*ptr), VHOST_ADDR_USED); \
862 if (to != NULL) \
863 ret = __put_user(x, to); \
864 else \
865 ret = -EFAULT; \
866 } \
867 ret; \
868 })
869
870 #define vhost_get_user(vq, x, ptr, type) \
871 ({ \
872 int ret; \
873 if (!vq->iotlb) { \
874 ret = __get_user(x, ptr); \
875 } else { \
876 __typeof__(ptr) from = \
877 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
878 sizeof(*ptr), \
879 type); \
880 if (from != NULL) \
881 ret = __get_user(x, from); \
882 else \
883 ret = -EFAULT; \
884 } \
885 ret; \
886 })
887
888 #define vhost_get_avail(vq, x, ptr) \
889 vhost_get_user(vq, x, ptr, VHOST_ADDR_AVAIL)
890
891 #define vhost_get_used(vq, x, ptr) \
892 vhost_get_user(vq, x, ptr, VHOST_ADDR_USED)
893
894 static void vhost_dev_lock_vqs(struct vhost_dev *d)
895 {
896 int i = 0;
897 for (i = 0; i < d->nvqs; ++i)
898 mutex_lock_nested(&d->vqs[i]->mutex, i);
899 }
900
901 static void vhost_dev_unlock_vqs(struct vhost_dev *d)
902 {
903 int i = 0;
904 for (i = 0; i < d->nvqs; ++i)
905 mutex_unlock(&d->vqs[i]->mutex);
906 }
907
908 static int vhost_new_umem_range(struct vhost_umem *umem,
909 u64 start, u64 size, u64 end,
910 u64 userspace_addr, int perm)
911 {
912 struct vhost_umem_node *tmp, *node = kmalloc(sizeof(*node), GFP_ATOMIC);
913
914 if (!node)
915 return -ENOMEM;
916
917 if (umem->numem == max_iotlb_entries) {
918 tmp = list_first_entry(&umem->umem_list, typeof(*tmp), link);
919 vhost_umem_free(umem, tmp);
920 }
921
922 node->start = start;
923 node->size = size;
924 node->last = end;
925 node->userspace_addr = userspace_addr;
926 node->perm = perm;
927 INIT_LIST_HEAD(&node->link);
928 list_add_tail(&node->link, &umem->umem_list);
929 vhost_umem_interval_tree_insert(node, &umem->umem_tree);
930 umem->numem++;
931
932 return 0;
933 }
934
935 static void vhost_del_umem_range(struct vhost_umem *umem,
936 u64 start, u64 end)
937 {
938 struct vhost_umem_node *node;
939
940 while ((node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
941 start, end)))
942 vhost_umem_free(umem, node);
943 }
944
945 static void vhost_iotlb_notify_vq(struct vhost_dev *d,
946 struct vhost_iotlb_msg *msg)
947 {
948 struct vhost_msg_node *node, *n;
949
950 spin_lock(&d->iotlb_lock);
951
952 list_for_each_entry_safe(node, n, &d->pending_list, node) {
953 struct vhost_iotlb_msg *vq_msg = &node->msg.iotlb;
954 if (msg->iova <= vq_msg->iova &&
955 msg->iova + msg->size - 1 >= vq_msg->iova &&
956 vq_msg->type == VHOST_IOTLB_MISS) {
957 vhost_poll_queue(&node->vq->poll);
958 list_del(&node->node);
959 kfree(node);
960 }
961 }
962
963 spin_unlock(&d->iotlb_lock);
964 }
965
966 static bool umem_access_ok(u64 uaddr, u64 size, int access)
967 {
968 unsigned long a = uaddr;
969
970 /* Make sure 64 bit math will not overflow. */
971 if (vhost_overflow(uaddr, size))
972 return false;
973
974 if ((access & VHOST_ACCESS_RO) &&
975 !access_ok(VERIFY_READ, (void __user *)a, size))
976 return false;
977 if ((access & VHOST_ACCESS_WO) &&
978 !access_ok(VERIFY_WRITE, (void __user *)a, size))
979 return false;
980 return true;
981 }
982
983 static int vhost_process_iotlb_msg(struct vhost_dev *dev,
984 struct vhost_iotlb_msg *msg)
985 {
986 int ret = 0;
987
988 mutex_lock(&dev->mutex);
989 vhost_dev_lock_vqs(dev);
990 switch (msg->type) {
991 case VHOST_IOTLB_UPDATE:
992 if (!dev->iotlb) {
993 ret = -EFAULT;
994 break;
995 }
996 if (!umem_access_ok(msg->uaddr, msg->size, msg->perm)) {
997 ret = -EFAULT;
998 break;
999 }
1000 vhost_vq_meta_reset(dev);
1001 if (vhost_new_umem_range(dev->iotlb, msg->iova, msg->size,
1002 msg->iova + msg->size - 1,
1003 msg->uaddr, msg->perm)) {
1004 ret = -ENOMEM;
1005 break;
1006 }
1007 vhost_iotlb_notify_vq(dev, msg);
1008 break;
1009 case VHOST_IOTLB_INVALIDATE:
1010 if (!dev->iotlb) {
1011 ret = -EFAULT;
1012 break;
1013 }
1014 vhost_vq_meta_reset(dev);
1015 vhost_del_umem_range(dev->iotlb, msg->iova,
1016 msg->iova + msg->size - 1);
1017 break;
1018 default:
1019 ret = -EINVAL;
1020 break;
1021 }
1022
1023 vhost_dev_unlock_vqs(dev);
1024 mutex_unlock(&dev->mutex);
1025
1026 return ret;
1027 }
1028 ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
1029 struct iov_iter *from)
1030 {
1031 struct vhost_iotlb_msg msg;
1032 size_t offset;
1033 int type, ret;
1034
1035 ret = copy_from_iter(&type, sizeof(type), from);
1036 if (ret != sizeof(type))
1037 goto done;
1038
1039 switch (type) {
1040 case VHOST_IOTLB_MSG:
1041 /* There maybe a hole after type for V1 message type,
1042 * so skip it here.
1043 */
1044 offset = offsetof(struct vhost_msg, iotlb) - sizeof(int);
1045 break;
1046 case VHOST_IOTLB_MSG_V2:
1047 offset = sizeof(__u32);
1048 break;
1049 default:
1050 ret = -EINVAL;
1051 goto done;
1052 }
1053
1054 iov_iter_advance(from, offset);
1055 ret = copy_from_iter(&msg, sizeof(msg), from);
1056 if (ret != sizeof(msg))
1057 goto done;
1058 if (vhost_process_iotlb_msg(dev, &msg)) {
1059 ret = -EFAULT;
1060 goto done;
1061 }
1062
1063 ret = (type == VHOST_IOTLB_MSG) ? sizeof(struct vhost_msg) :
1064 sizeof(struct vhost_msg_v2);
1065 done:
1066 return ret;
1067 }
1068 EXPORT_SYMBOL(vhost_chr_write_iter);
1069
1070 __poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
1071 poll_table *wait)
1072 {
1073 __poll_t mask = 0;
1074
1075 poll_wait(file, &dev->wait, wait);
1076
1077 if (!list_empty(&dev->read_list))
1078 mask |= EPOLLIN | EPOLLRDNORM;
1079
1080 return mask;
1081 }
1082 EXPORT_SYMBOL(vhost_chr_poll);
1083
1084 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
1085 int noblock)
1086 {
1087 DEFINE_WAIT(wait);
1088 struct vhost_msg_node *node;
1089 ssize_t ret = 0;
1090 unsigned size = sizeof(struct vhost_msg);
1091
1092 if (iov_iter_count(to) < size)
1093 return 0;
1094
1095 while (1) {
1096 if (!noblock)
1097 prepare_to_wait(&dev->wait, &wait,
1098 TASK_INTERRUPTIBLE);
1099
1100 node = vhost_dequeue_msg(dev, &dev->read_list);
1101 if (node)
1102 break;
1103 if (noblock) {
1104 ret = -EAGAIN;
1105 break;
1106 }
1107 if (signal_pending(current)) {
1108 ret = -ERESTARTSYS;
1109 break;
1110 }
1111 if (!dev->iotlb) {
1112 ret = -EBADFD;
1113 break;
1114 }
1115
1116 schedule();
1117 }
1118
1119 if (!noblock)
1120 finish_wait(&dev->wait, &wait);
1121
1122 if (node) {
1123 struct vhost_iotlb_msg *msg;
1124 void *start = &node->msg;
1125
1126 switch (node->msg.type) {
1127 case VHOST_IOTLB_MSG:
1128 size = sizeof(node->msg);
1129 msg = &node->msg.iotlb;
1130 break;
1131 case VHOST_IOTLB_MSG_V2:
1132 size = sizeof(node->msg_v2);
1133 msg = &node->msg_v2.iotlb;
1134 break;
1135 default:
1136 BUG();
1137 break;
1138 }
1139
1140 ret = copy_to_iter(start, size, to);
1141 if (ret != size || msg->type != VHOST_IOTLB_MISS) {
1142 kfree(node);
1143 return ret;
1144 }
1145 vhost_enqueue_msg(dev, &dev->pending_list, node);
1146 }
1147
1148 return ret;
1149 }
1150 EXPORT_SYMBOL_GPL(vhost_chr_read_iter);
1151
1152 static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access)
1153 {
1154 struct vhost_dev *dev = vq->dev;
1155 struct vhost_msg_node *node;
1156 struct vhost_iotlb_msg *msg;
1157 bool v2 = vhost_backend_has_feature(vq, VHOST_BACKEND_F_IOTLB_MSG_V2);
1158
1159 node = vhost_new_msg(vq, v2 ? VHOST_IOTLB_MSG_V2 : VHOST_IOTLB_MSG);
1160 if (!node)
1161 return -ENOMEM;
1162
1163 if (v2) {
1164 node->msg_v2.type = VHOST_IOTLB_MSG_V2;
1165 msg = &node->msg_v2.iotlb;
1166 } else {
1167 msg = &node->msg.iotlb;
1168 }
1169
1170 msg->type = VHOST_IOTLB_MISS;
1171 msg->iova = iova;
1172 msg->perm = access;
1173
1174 vhost_enqueue_msg(dev, &dev->read_list, node);
1175
1176 return 0;
1177 }
1178
1179 static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
1180 struct vring_desc __user *desc,
1181 struct vring_avail __user *avail,
1182 struct vring_used __user *used)
1183
1184 {
1185 size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
1186
1187 return access_ok(VERIFY_READ, desc, num * sizeof *desc) &&
1188 access_ok(VERIFY_READ, avail,
1189 sizeof *avail + num * sizeof *avail->ring + s) &&
1190 access_ok(VERIFY_WRITE, used,
1191 sizeof *used + num * sizeof *used->ring + s);
1192 }
1193
1194 static void vhost_vq_meta_update(struct vhost_virtqueue *vq,
1195 const struct vhost_umem_node *node,
1196 int type)
1197 {
1198 int access = (type == VHOST_ADDR_USED) ?
1199 VHOST_ACCESS_WO : VHOST_ACCESS_RO;
1200
1201 if (likely(node->perm & access))
1202 vq->meta_iotlb[type] = node;
1203 }
1204
1205 static bool iotlb_access_ok(struct vhost_virtqueue *vq,
1206 int access, u64 addr, u64 len, int type)
1207 {
1208 const struct vhost_umem_node *node;
1209 struct vhost_umem *umem = vq->iotlb;
1210 u64 s = 0, size, orig_addr = addr, last = addr + len - 1;
1211
1212 if (vhost_vq_meta_fetch(vq, addr, len, type))
1213 return true;
1214
1215 while (len > s) {
1216 node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
1217 addr,
1218 last);
1219 if (node == NULL || node->start > addr) {
1220 vhost_iotlb_miss(vq, addr, access);
1221 return false;
1222 } else if (!(node->perm & access)) {
1223 /* Report the possible access violation by
1224 * request another translation from userspace.
1225 */
1226 return false;
1227 }
1228
1229 size = node->size - addr + node->start;
1230
1231 if (orig_addr == addr && size >= len)
1232 vhost_vq_meta_update(vq, node, type);
1233
1234 s += size;
1235 addr += size;
1236 }
1237
1238 return true;
1239 }
1240
1241 int vq_iotlb_prefetch(struct vhost_virtqueue *vq)
1242 {
1243 size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
1244 unsigned int num = vq->num;
1245
1246 if (!vq->iotlb)
1247 return 1;
1248
1249 return iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->desc,
1250 num * sizeof(*vq->desc), VHOST_ADDR_DESC) &&
1251 iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->avail,
1252 sizeof *vq->avail +
1253 num * sizeof(*vq->avail->ring) + s,
1254 VHOST_ADDR_AVAIL) &&
1255 iotlb_access_ok(vq, VHOST_ACCESS_WO, (u64)(uintptr_t)vq->used,
1256 sizeof *vq->used +
1257 num * sizeof(*vq->used->ring) + s,
1258 VHOST_ADDR_USED);
1259 }
1260 EXPORT_SYMBOL_GPL(vq_iotlb_prefetch);
1261
1262 /* Can we log writes? */
1263 /* Caller should have device mutex but not vq mutex */
1264 bool vhost_log_access_ok(struct vhost_dev *dev)
1265 {
1266 return memory_access_ok(dev, dev->umem, 1);
1267 }
1268 EXPORT_SYMBOL_GPL(vhost_log_access_ok);
1269
1270 /* Verify access for write logging. */
1271 /* Caller should have vq mutex and device mutex */
1272 static bool vq_log_access_ok(struct vhost_virtqueue *vq,
1273 void __user *log_base)
1274 {
1275 size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
1276
1277 return vq_memory_access_ok(log_base, vq->umem,
1278 vhost_has_feature(vq, VHOST_F_LOG_ALL)) &&
1279 (!vq->log_used || log_access_ok(log_base, vq->log_addr,
1280 sizeof *vq->used +
1281 vq->num * sizeof *vq->used->ring + s));
1282 }
1283
1284 /* Can we start vq? */
1285 /* Caller should have vq mutex and device mutex */
1286 bool vhost_vq_access_ok(struct vhost_virtqueue *vq)
1287 {
1288 if (!vq_log_access_ok(vq, vq->log_base))
1289 return false;
1290
1291 /* Access validation occurs at prefetch time with IOTLB */
1292 if (vq->iotlb)
1293 return true;
1294
1295 return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used);
1296 }
1297 EXPORT_SYMBOL_GPL(vhost_vq_access_ok);
1298
1299 static struct vhost_umem *vhost_umem_alloc(void)
1300 {
1301 struct vhost_umem *umem = kvzalloc(sizeof(*umem), GFP_KERNEL);
1302
1303 if (!umem)
1304 return NULL;
1305
1306 umem->umem_tree = RB_ROOT_CACHED;
1307 umem->numem = 0;
1308 INIT_LIST_HEAD(&umem->umem_list);
1309
1310 return umem;
1311 }
1312
1313 static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
1314 {
1315 struct vhost_memory mem, *newmem;
1316 struct vhost_memory_region *region;
1317 struct vhost_umem *newumem, *oldumem;
1318 unsigned long size = offsetof(struct vhost_memory, regions);
1319 int i;
1320
1321 if (copy_from_user(&mem, m, size))
1322 return -EFAULT;
1323 if (mem.padding)
1324 return -EOPNOTSUPP;
1325 if (mem.nregions > max_mem_regions)
1326 return -E2BIG;
1327 newmem = kvzalloc(struct_size(newmem, regions, mem.nregions),
1328 GFP_KERNEL);
1329 if (!newmem)
1330 return -ENOMEM;
1331
1332 memcpy(newmem, &mem, size);
1333 if (copy_from_user(newmem->regions, m->regions,
1334 mem.nregions * sizeof *m->regions)) {
1335 kvfree(newmem);
1336 return -EFAULT;
1337 }
1338
1339 newumem = vhost_umem_alloc();
1340 if (!newumem) {
1341 kvfree(newmem);
1342 return -ENOMEM;
1343 }
1344
1345 for (region = newmem->regions;
1346 region < newmem->regions + mem.nregions;
1347 region++) {
1348 if (vhost_new_umem_range(newumem,
1349 region->guest_phys_addr,
1350 region->memory_size,
1351 region->guest_phys_addr +
1352 region->memory_size - 1,
1353 region->userspace_addr,
1354 VHOST_ACCESS_RW))
1355 goto err;
1356 }
1357
1358 if (!memory_access_ok(d, newumem, 0))
1359 goto err;
1360
1361 oldumem = d->umem;
1362 d->umem = newumem;
1363
1364 /* All memory accesses are done under some VQ mutex. */
1365 for (i = 0; i < d->nvqs; ++i) {
1366 mutex_lock(&d->vqs[i]->mutex);
1367 d->vqs[i]->umem = newumem;
1368 mutex_unlock(&d->vqs[i]->mutex);
1369 }
1370
1371 kvfree(newmem);
1372 vhost_umem_clean(oldumem);
1373 return 0;
1374
1375 err:
1376 vhost_umem_clean(newumem);
1377 kvfree(newmem);
1378 return -EFAULT;
1379 }
1380
1381 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
1382 {
1383 struct file *eventfp, *filep = NULL;
1384 bool pollstart = false, pollstop = false;
1385 struct eventfd_ctx *ctx = NULL;
1386 u32 __user *idxp = argp;
1387 struct vhost_virtqueue *vq;
1388 struct vhost_vring_state s;
1389 struct vhost_vring_file f;
1390 struct vhost_vring_addr a;
1391 u32 idx;
1392 long r;
1393
1394 r = get_user(idx, idxp);
1395 if (r < 0)
1396 return r;
1397 if (idx >= d->nvqs)
1398 return -ENOBUFS;
1399
1400 vq = d->vqs[idx];
1401
1402 mutex_lock(&vq->mutex);
1403
1404 switch (ioctl) {
1405 case VHOST_SET_VRING_NUM:
1406 /* Resizing ring with an active backend?
1407 * You don't want to do that. */
1408 if (vq->private_data) {
1409 r = -EBUSY;
1410 break;
1411 }
1412 if (copy_from_user(&s, argp, sizeof s)) {
1413 r = -EFAULT;
1414 break;
1415 }
1416 if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) {
1417 r = -EINVAL;
1418 break;
1419 }
1420 vq->num = s.num;
1421 break;
1422 case VHOST_SET_VRING_BASE:
1423 /* Moving base with an active backend?
1424 * You don't want to do that. */
1425 if (vq->private_data) {
1426 r = -EBUSY;
1427 break;
1428 }
1429 if (copy_from_user(&s, argp, sizeof s)) {
1430 r = -EFAULT;
1431 break;
1432 }
1433 if (s.num > 0xffff) {
1434 r = -EINVAL;
1435 break;
1436 }
1437 vq->last_avail_idx = s.num;
1438 /* Forget the cached index value. */
1439 vq->avail_idx = vq->last_avail_idx;
1440 break;
1441 case VHOST_GET_VRING_BASE:
1442 s.index = idx;
1443 s.num = vq->last_avail_idx;
1444 if (copy_to_user(argp, &s, sizeof s))
1445 r = -EFAULT;
1446 break;
1447 case VHOST_SET_VRING_ADDR:
1448 if (copy_from_user(&a, argp, sizeof a)) {
1449 r = -EFAULT;
1450 break;
1451 }
1452 if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) {
1453 r = -EOPNOTSUPP;
1454 break;
1455 }
1456 /* For 32bit, verify that the top 32bits of the user
1457 data are set to zero. */
1458 if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr ||
1459 (u64)(unsigned long)a.used_user_addr != a.used_user_addr ||
1460 (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) {
1461 r = -EFAULT;
1462 break;
1463 }
1464
1465 /* Make sure it's safe to cast pointers to vring types. */
1466 BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE);
1467 BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE);
1468 if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) ||
1469 (a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) ||
1470 (a.log_guest_addr & (VRING_USED_ALIGN_SIZE - 1))) {
1471 r = -EINVAL;
1472 break;
1473 }
1474
1475 /* We only verify access here if backend is configured.
1476 * If it is not, we don't as size might not have been setup.
1477 * We will verify when backend is configured. */
1478 if (vq->private_data) {
1479 if (!vq_access_ok(vq, vq->num,
1480 (void __user *)(unsigned long)a.desc_user_addr,
1481 (void __user *)(unsigned long)a.avail_user_addr,
1482 (void __user *)(unsigned long)a.used_user_addr)) {
1483 r = -EINVAL;
1484 break;
1485 }
1486
1487 /* Also validate log access for used ring if enabled. */
1488 if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) &&
1489 !log_access_ok(vq->log_base, a.log_guest_addr,
1490 sizeof *vq->used +
1491 vq->num * sizeof *vq->used->ring)) {
1492 r = -EINVAL;
1493 break;
1494 }
1495 }
1496
1497 vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG));
1498 vq->desc = (void __user *)(unsigned long)a.desc_user_addr;
1499 vq->avail = (void __user *)(unsigned long)a.avail_user_addr;
1500 vq->log_addr = a.log_guest_addr;
1501 vq->used = (void __user *)(unsigned long)a.used_user_addr;
1502 break;
1503 case VHOST_SET_VRING_KICK:
1504 if (copy_from_user(&f, argp, sizeof f)) {
1505 r = -EFAULT;
1506 break;
1507 }
1508 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
1509 if (IS_ERR(eventfp)) {
1510 r = PTR_ERR(eventfp);
1511 break;
1512 }
1513 if (eventfp != vq->kick) {
1514 pollstop = (filep = vq->kick) != NULL;
1515 pollstart = (vq->kick = eventfp) != NULL;
1516 } else
1517 filep = eventfp;
1518 break;
1519 case VHOST_SET_VRING_CALL:
1520 if (copy_from_user(&f, argp, sizeof f)) {
1521 r = -EFAULT;
1522 break;
1523 }
1524 ctx = f.fd == -1 ? NULL : eventfd_ctx_fdget(f.fd);
1525 if (IS_ERR(ctx)) {
1526 r = PTR_ERR(ctx);
1527 break;
1528 }
1529 swap(ctx, vq->call_ctx);
1530 break;
1531 case VHOST_SET_VRING_ERR:
1532 if (copy_from_user(&f, argp, sizeof f)) {
1533 r = -EFAULT;
1534 break;
1535 }
1536 ctx = f.fd == -1 ? NULL : eventfd_ctx_fdget(f.fd);
1537 if (IS_ERR(ctx)) {
1538 r = PTR_ERR(ctx);
1539 break;
1540 }
1541 swap(ctx, vq->error_ctx);
1542 break;
1543 case VHOST_SET_VRING_ENDIAN:
1544 r = vhost_set_vring_endian(vq, argp);
1545 break;
1546 case VHOST_GET_VRING_ENDIAN:
1547 r = vhost_get_vring_endian(vq, idx, argp);
1548 break;
1549 case VHOST_SET_VRING_BUSYLOOP_TIMEOUT:
1550 if (copy_from_user(&s, argp, sizeof(s))) {
1551 r = -EFAULT;
1552 break;
1553 }
1554 vq->busyloop_timeout = s.num;
1555 break;
1556 case VHOST_GET_VRING_BUSYLOOP_TIMEOUT:
1557 s.index = idx;
1558 s.num = vq->busyloop_timeout;
1559 if (copy_to_user(argp, &s, sizeof(s)))
1560 r = -EFAULT;
1561 break;
1562 default:
1563 r = -ENOIOCTLCMD;
1564 }
1565
1566 if (pollstop && vq->handle_kick)
1567 vhost_poll_stop(&vq->poll);
1568
1569 if (!IS_ERR_OR_NULL(ctx))
1570 eventfd_ctx_put(ctx);
1571 if (filep)
1572 fput(filep);
1573
1574 if (pollstart && vq->handle_kick)
1575 r = vhost_poll_start(&vq->poll, vq->kick);
1576
1577 mutex_unlock(&vq->mutex);
1578
1579 if (pollstop && vq->handle_kick)
1580 vhost_poll_flush(&vq->poll);
1581 return r;
1582 }
1583 EXPORT_SYMBOL_GPL(vhost_vring_ioctl);
1584
1585 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled)
1586 {
1587 struct vhost_umem *niotlb, *oiotlb;
1588 int i;
1589
1590 niotlb = vhost_umem_alloc();
1591 if (!niotlb)
1592 return -ENOMEM;
1593
1594 oiotlb = d->iotlb;
1595 d->iotlb = niotlb;
1596
1597 for (i = 0; i < d->nvqs; ++i) {
1598 struct vhost_virtqueue *vq = d->vqs[i];
1599
1600 mutex_lock(&vq->mutex);
1601 vq->iotlb = niotlb;
1602 __vhost_vq_meta_reset(vq);
1603 mutex_unlock(&vq->mutex);
1604 }
1605
1606 vhost_umem_clean(oiotlb);
1607
1608 return 0;
1609 }
1610 EXPORT_SYMBOL_GPL(vhost_init_device_iotlb);
1611
1612 /* Caller must have device mutex */
1613 long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
1614 {
1615 struct eventfd_ctx *ctx;
1616 u64 p;
1617 long r;
1618 int i, fd;
1619
1620 /* If you are not the owner, you can become one */
1621 if (ioctl == VHOST_SET_OWNER) {
1622 r = vhost_dev_set_owner(d);
1623 goto done;
1624 }
1625
1626 /* You must be the owner to do anything else */
1627 r = vhost_dev_check_owner(d);
1628 if (r)
1629 goto done;
1630
1631 switch (ioctl) {
1632 case VHOST_SET_MEM_TABLE:
1633 r = vhost_set_memory(d, argp);
1634 break;
1635 case VHOST_SET_LOG_BASE:
1636 if (copy_from_user(&p, argp, sizeof p)) {
1637 r = -EFAULT;
1638 break;
1639 }
1640 if ((u64)(unsigned long)p != p) {
1641 r = -EFAULT;
1642 break;
1643 }
1644 for (i = 0; i < d->nvqs; ++i) {
1645 struct vhost_virtqueue *vq;
1646 void __user *base = (void __user *)(unsigned long)p;
1647 vq = d->vqs[i];
1648 mutex_lock(&vq->mutex);
1649 /* If ring is inactive, will check when it's enabled. */
1650 if (vq->private_data && !vq_log_access_ok(vq, base))
1651 r = -EFAULT;
1652 else
1653 vq->log_base = base;
1654 mutex_unlock(&vq->mutex);
1655 }
1656 break;
1657 case VHOST_SET_LOG_FD:
1658 r = get_user(fd, (int __user *)argp);
1659 if (r < 0)
1660 break;
1661 ctx = fd == -1 ? NULL : eventfd_ctx_fdget(fd);
1662 if (IS_ERR(ctx)) {
1663 r = PTR_ERR(ctx);
1664 break;
1665 }
1666 swap(ctx, d->log_ctx);
1667 for (i = 0; i < d->nvqs; ++i) {
1668 mutex_lock(&d->vqs[i]->mutex);
1669 d->vqs[i]->log_ctx = d->log_ctx;
1670 mutex_unlock(&d->vqs[i]->mutex);
1671 }
1672 if (ctx)
1673 eventfd_ctx_put(ctx);
1674 break;
1675 default:
1676 r = -ENOIOCTLCMD;
1677 break;
1678 }
1679 done:
1680 return r;
1681 }
1682 EXPORT_SYMBOL_GPL(vhost_dev_ioctl);
1683
1684 /* TODO: This is really inefficient. We need something like get_user()
1685 * (instruction directly accesses the data, with an exception table entry
1686 * returning -EFAULT). See Documentation/x86/exception-tables.txt.
1687 */
1688 static int set_bit_to_user(int nr, void __user *addr)
1689 {
1690 unsigned long log = (unsigned long)addr;
1691 struct page *page;
1692 void *base;
1693 int bit = nr + (log % PAGE_SIZE) * 8;
1694 int r;
1695
1696 r = get_user_pages_fast(log, 1, 1, &page);
1697 if (r < 0)
1698 return r;
1699 BUG_ON(r != 1);
1700 base = kmap_atomic(page);
1701 set_bit(bit, base);
1702 kunmap_atomic(base);
1703 set_page_dirty_lock(page);
1704 put_page(page);
1705 return 0;
1706 }
1707
1708 static int log_write(void __user *log_base,
1709 u64 write_address, u64 write_length)
1710 {
1711 u64 write_page = write_address / VHOST_PAGE_SIZE;
1712 int r;
1713
1714 if (!write_length)
1715 return 0;
1716 write_length += write_address % VHOST_PAGE_SIZE;
1717 for (;;) {
1718 u64 base = (u64)(unsigned long)log_base;
1719 u64 log = base + write_page / 8;
1720 int bit = write_page % 8;
1721 if ((u64)(unsigned long)log != log)
1722 return -EFAULT;
1723 r = set_bit_to_user(bit, (void __user *)(unsigned long)log);
1724 if (r < 0)
1725 return r;
1726 if (write_length <= VHOST_PAGE_SIZE)
1727 break;
1728 write_length -= VHOST_PAGE_SIZE;
1729 write_page += 1;
1730 }
1731 return r;
1732 }
1733
1734 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
1735 unsigned int log_num, u64 len)
1736 {
1737 int i, r;
1738
1739 /* Make sure data written is seen before log. */
1740 smp_wmb();
1741 for (i = 0; i < log_num; ++i) {
1742 u64 l = min(log[i].len, len);
1743 r = log_write(vq->log_base, log[i].addr, l);
1744 if (r < 0)
1745 return r;
1746 len -= l;
1747 if (!len) {
1748 if (vq->log_ctx)
1749 eventfd_signal(vq->log_ctx, 1);
1750 return 0;
1751 }
1752 }
1753 /* Length written exceeds what we have stored. This is a bug. */
1754 BUG();
1755 return 0;
1756 }
1757 EXPORT_SYMBOL_GPL(vhost_log_write);
1758
1759 static int vhost_update_used_flags(struct vhost_virtqueue *vq)
1760 {
1761 void __user *used;
1762 if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags),
1763 &vq->used->flags) < 0)
1764 return -EFAULT;
1765 if (unlikely(vq->log_used)) {
1766 /* Make sure the flag is seen before log. */
1767 smp_wmb();
1768 /* Log used flag write. */
1769 used = &vq->used->flags;
1770 log_write(vq->log_base, vq->log_addr +
1771 (used - (void __user *)vq->used),
1772 sizeof vq->used->flags);
1773 if (vq->log_ctx)
1774 eventfd_signal(vq->log_ctx, 1);
1775 }
1776 return 0;
1777 }
1778
1779 static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
1780 {
1781 if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx),
1782 vhost_avail_event(vq)))
1783 return -EFAULT;
1784 if (unlikely(vq->log_used)) {
1785 void __user *used;
1786 /* Make sure the event is seen before log. */
1787 smp_wmb();
1788 /* Log avail event write */
1789 used = vhost_avail_event(vq);
1790 log_write(vq->log_base, vq->log_addr +
1791 (used - (void __user *)vq->used),
1792 sizeof *vhost_avail_event(vq));
1793 if (vq->log_ctx)
1794 eventfd_signal(vq->log_ctx, 1);
1795 }
1796 return 0;
1797 }
1798
1799 int vhost_vq_init_access(struct vhost_virtqueue *vq)
1800 {
1801 __virtio16 last_used_idx;
1802 int r;
1803 bool is_le = vq->is_le;
1804
1805 if (!vq->private_data)
1806 return 0;
1807
1808 vhost_init_is_le(vq);
1809
1810 r = vhost_update_used_flags(vq);
1811 if (r)
1812 goto err;
1813 vq->signalled_used_valid = false;
1814 if (!vq->iotlb &&
1815 !access_ok(VERIFY_READ, &vq->used->idx, sizeof vq->used->idx)) {
1816 r = -EFAULT;
1817 goto err;
1818 }
1819 r = vhost_get_used(vq, last_used_idx, &vq->used->idx);
1820 if (r) {
1821 vq_err(vq, "Can't access used idx at %p\n",
1822 &vq->used->idx);
1823 goto err;
1824 }
1825 vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx);
1826 return 0;
1827
1828 err:
1829 vq->is_le = is_le;
1830 return r;
1831 }
1832 EXPORT_SYMBOL_GPL(vhost_vq_init_access);
1833
1834 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
1835 struct iovec iov[], int iov_size, int access)
1836 {
1837 const struct vhost_umem_node *node;
1838 struct vhost_dev *dev = vq->dev;
1839 struct vhost_umem *umem = dev->iotlb ? dev->iotlb : dev->umem;
1840 struct iovec *_iov;
1841 u64 s = 0;
1842 int ret = 0;
1843
1844 while ((u64)len > s) {
1845 u64 size;
1846 if (unlikely(ret >= iov_size)) {
1847 ret = -ENOBUFS;
1848 break;
1849 }
1850
1851 node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
1852 addr, addr + len - 1);
1853 if (node == NULL || node->start > addr) {
1854 if (umem != dev->iotlb) {
1855 ret = -EFAULT;
1856 break;
1857 }
1858 ret = -EAGAIN;
1859 break;
1860 } else if (!(node->perm & access)) {
1861 ret = -EPERM;
1862 break;
1863 }
1864
1865 _iov = iov + ret;
1866 size = node->size - addr + node->start;
1867 _iov->iov_len = min((u64)len - s, size);
1868 _iov->iov_base = (void __user *)(unsigned long)
1869 (node->userspace_addr + addr - node->start);
1870 s += size;
1871 addr += size;
1872 ++ret;
1873 }
1874
1875 if (ret == -EAGAIN)
1876 vhost_iotlb_miss(vq, addr, access);
1877 return ret;
1878 }
1879
1880 /* Each buffer in the virtqueues is actually a chain of descriptors. This
1881 * function returns the next descriptor in the chain,
1882 * or -1U if we're at the end. */
1883 static unsigned next_desc(struct vhost_virtqueue *vq, struct vring_desc *desc)
1884 {
1885 unsigned int next;
1886
1887 /* If this descriptor says it doesn't chain, we're done. */
1888 if (!(desc->flags & cpu_to_vhost16(vq, VRING_DESC_F_NEXT)))
1889 return -1U;
1890
1891 /* Check they're not leading us off end of descriptors. */
1892 next = vhost16_to_cpu(vq, READ_ONCE(desc->next));
1893 return next;
1894 }
1895
1896 static int get_indirect(struct vhost_virtqueue *vq,
1897 struct iovec iov[], unsigned int iov_size,
1898 unsigned int *out_num, unsigned int *in_num,
1899 struct vhost_log *log, unsigned int *log_num,
1900 struct vring_desc *indirect)
1901 {
1902 struct vring_desc desc;
1903 unsigned int i = 0, count, found = 0;
1904 u32 len = vhost32_to_cpu(vq, indirect->len);
1905 struct iov_iter from;
1906 int ret, access;
1907
1908 /* Sanity check */
1909 if (unlikely(len % sizeof desc)) {
1910 vq_err(vq, "Invalid length in indirect descriptor: "
1911 "len 0x%llx not multiple of 0x%zx\n",
1912 (unsigned long long)len,
1913 sizeof desc);
1914 return -EINVAL;
1915 }
1916
1917 ret = translate_desc(vq, vhost64_to_cpu(vq, indirect->addr), len, vq->indirect,
1918 UIO_MAXIOV, VHOST_ACCESS_RO);
1919 if (unlikely(ret < 0)) {
1920 if (ret != -EAGAIN)
1921 vq_err(vq, "Translation failure %d in indirect.\n", ret);
1922 return ret;
1923 }
1924 iov_iter_init(&from, READ, vq->indirect, ret, len);
1925
1926 /* We will use the result as an address to read from, so most
1927 * architectures only need a compiler barrier here. */
1928 read_barrier_depends();
1929
1930 count = len / sizeof desc;
1931 /* Buffers are chained via a 16 bit next field, so
1932 * we can have at most 2^16 of these. */
1933 if (unlikely(count > USHRT_MAX + 1)) {
1934 vq_err(vq, "Indirect buffer length too big: %d\n",
1935 indirect->len);
1936 return -E2BIG;
1937 }
1938
1939 do {
1940 unsigned iov_count = *in_num + *out_num;
1941 if (unlikely(++found > count)) {
1942 vq_err(vq, "Loop detected: last one at %u "
1943 "indirect size %u\n",
1944 i, count);
1945 return -EINVAL;
1946 }
1947 if (unlikely(!copy_from_iter_full(&desc, sizeof(desc), &from))) {
1948 vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
1949 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
1950 return -EINVAL;
1951 }
1952 if (unlikely(desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT))) {
1953 vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n",
1954 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
1955 return -EINVAL;
1956 }
1957
1958 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
1959 access = VHOST_ACCESS_WO;
1960 else
1961 access = VHOST_ACCESS_RO;
1962
1963 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
1964 vhost32_to_cpu(vq, desc.len), iov + iov_count,
1965 iov_size - iov_count, access);
1966 if (unlikely(ret < 0)) {
1967 if (ret != -EAGAIN)
1968 vq_err(vq, "Translation failure %d indirect idx %d\n",
1969 ret, i);
1970 return ret;
1971 }
1972 /* If this is an input descriptor, increment that count. */
1973 if (access == VHOST_ACCESS_WO) {
1974 *in_num += ret;
1975 if (unlikely(log)) {
1976 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
1977 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
1978 ++*log_num;
1979 }
1980 } else {
1981 /* If it's an output descriptor, they're all supposed
1982 * to come before any input descriptors. */
1983 if (unlikely(*in_num)) {
1984 vq_err(vq, "Indirect descriptor "
1985 "has out after in: idx %d\n", i);
1986 return -EINVAL;
1987 }
1988 *out_num += ret;
1989 }
1990 } while ((i = next_desc(vq, &desc)) != -1);
1991 return 0;
1992 }
1993
1994 /* This looks in the virtqueue and for the first available buffer, and converts
1995 * it to an iovec for convenient access. Since descriptors consist of some
1996 * number of output then some number of input descriptors, it's actually two
1997 * iovecs, but we pack them into one and note how many of each there were.
1998 *
1999 * This function returns the descriptor number found, or vq->num (which is
2000 * never a valid descriptor number) if none was found. A negative code is
2001 * returned on error. */
2002 int vhost_get_vq_desc(struct vhost_virtqueue *vq,
2003 struct iovec iov[], unsigned int iov_size,
2004 unsigned int *out_num, unsigned int *in_num,
2005 struct vhost_log *log, unsigned int *log_num)
2006 {
2007 struct vring_desc desc;
2008 unsigned int i, head, found = 0;
2009 u16 last_avail_idx;
2010 __virtio16 avail_idx;
2011 __virtio16 ring_head;
2012 int ret, access;
2013
2014 /* Check it isn't doing very strange things with descriptor numbers. */
2015 last_avail_idx = vq->last_avail_idx;
2016
2017 if (vq->avail_idx == vq->last_avail_idx) {
2018 if (unlikely(vhost_get_avail(vq, avail_idx, &vq->avail->idx))) {
2019 vq_err(vq, "Failed to access avail idx at %p\n",
2020 &vq->avail->idx);
2021 return -EFAULT;
2022 }
2023 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2024
2025 if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) {
2026 vq_err(vq, "Guest moved used index from %u to %u",
2027 last_avail_idx, vq->avail_idx);
2028 return -EFAULT;
2029 }
2030
2031 /* If there's nothing new since last we looked, return
2032 * invalid.
2033 */
2034 if (vq->avail_idx == last_avail_idx)
2035 return vq->num;
2036
2037 /* Only get avail ring entries after they have been
2038 * exposed by guest.
2039 */
2040 smp_rmb();
2041 }
2042
2043 /* Grab the next descriptor number they're advertising, and increment
2044 * the index we've seen. */
2045 if (unlikely(vhost_get_avail(vq, ring_head,
2046 &vq->avail->ring[last_avail_idx & (vq->num - 1)]))) {
2047 vq_err(vq, "Failed to read head: idx %d address %p\n",
2048 last_avail_idx,
2049 &vq->avail->ring[last_avail_idx % vq->num]);
2050 return -EFAULT;
2051 }
2052
2053 head = vhost16_to_cpu(vq, ring_head);
2054
2055 /* If their number is silly, that's an error. */
2056 if (unlikely(head >= vq->num)) {
2057 vq_err(vq, "Guest says index %u > %u is available",
2058 head, vq->num);
2059 return -EINVAL;
2060 }
2061
2062 /* When we start there are none of either input nor output. */
2063 *out_num = *in_num = 0;
2064 if (unlikely(log))
2065 *log_num = 0;
2066
2067 i = head;
2068 do {
2069 unsigned iov_count = *in_num + *out_num;
2070 if (unlikely(i >= vq->num)) {
2071 vq_err(vq, "Desc index is %u > %u, head = %u",
2072 i, vq->num, head);
2073 return -EINVAL;
2074 }
2075 if (unlikely(++found > vq->num)) {
2076 vq_err(vq, "Loop detected: last one at %u "
2077 "vq size %u head %u\n",
2078 i, vq->num, head);
2079 return -EINVAL;
2080 }
2081 ret = vhost_copy_from_user(vq, &desc, vq->desc + i,
2082 sizeof desc);
2083 if (unlikely(ret)) {
2084 vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
2085 i, vq->desc + i);
2086 return -EFAULT;
2087 }
2088 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT)) {
2089 ret = get_indirect(vq, iov, iov_size,
2090 out_num, in_num,
2091 log, log_num, &desc);
2092 if (unlikely(ret < 0)) {
2093 if (ret != -EAGAIN)
2094 vq_err(vq, "Failure detected "
2095 "in indirect descriptor at idx %d\n", i);
2096 return ret;
2097 }
2098 continue;
2099 }
2100
2101 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
2102 access = VHOST_ACCESS_WO;
2103 else
2104 access = VHOST_ACCESS_RO;
2105 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
2106 vhost32_to_cpu(vq, desc.len), iov + iov_count,
2107 iov_size - iov_count, access);
2108 if (unlikely(ret < 0)) {
2109 if (ret != -EAGAIN)
2110 vq_err(vq, "Translation failure %d descriptor idx %d\n",
2111 ret, i);
2112 return ret;
2113 }
2114 if (access == VHOST_ACCESS_WO) {
2115 /* If this is an input descriptor,
2116 * increment that count. */
2117 *in_num += ret;
2118 if (unlikely(log)) {
2119 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
2120 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
2121 ++*log_num;
2122 }
2123 } else {
2124 /* If it's an output descriptor, they're all supposed
2125 * to come before any input descriptors. */
2126 if (unlikely(*in_num)) {
2127 vq_err(vq, "Descriptor has out after in: "
2128 "idx %d\n", i);
2129 return -EINVAL;
2130 }
2131 *out_num += ret;
2132 }
2133 } while ((i = next_desc(vq, &desc)) != -1);
2134
2135 /* On success, increment avail index. */
2136 vq->last_avail_idx++;
2137
2138 /* Assume notifications from guest are disabled at this point,
2139 * if they aren't we would need to update avail_event index. */
2140 BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY));
2141 return head;
2142 }
2143 EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
2144
2145 /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
2146 void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n)
2147 {
2148 vq->last_avail_idx -= n;
2149 }
2150 EXPORT_SYMBOL_GPL(vhost_discard_vq_desc);
2151
2152 /* After we've used one of their buffers, we tell them about it. We'll then
2153 * want to notify the guest, using eventfd. */
2154 int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
2155 {
2156 struct vring_used_elem heads = {
2157 cpu_to_vhost32(vq, head),
2158 cpu_to_vhost32(vq, len)
2159 };
2160
2161 return vhost_add_used_n(vq, &heads, 1);
2162 }
2163 EXPORT_SYMBOL_GPL(vhost_add_used);
2164
2165 static int __vhost_add_used_n(struct vhost_virtqueue *vq,
2166 struct vring_used_elem *heads,
2167 unsigned count)
2168 {
2169 struct vring_used_elem __user *used;
2170 u16 old, new;
2171 int start;
2172
2173 start = vq->last_used_idx & (vq->num - 1);
2174 used = vq->used->ring + start;
2175 if (count == 1) {
2176 if (vhost_put_user(vq, heads[0].id, &used->id)) {
2177 vq_err(vq, "Failed to write used id");
2178 return -EFAULT;
2179 }
2180 if (vhost_put_user(vq, heads[0].len, &used->len)) {
2181 vq_err(vq, "Failed to write used len");
2182 return -EFAULT;
2183 }
2184 } else if (vhost_copy_to_user(vq, used, heads, count * sizeof *used)) {
2185 vq_err(vq, "Failed to write used");
2186 return -EFAULT;
2187 }
2188 if (unlikely(vq->log_used)) {
2189 /* Make sure data is seen before log. */
2190 smp_wmb();
2191 /* Log used ring entry write. */
2192 log_write(vq->log_base,
2193 vq->log_addr +
2194 ((void __user *)used - (void __user *)vq->used),
2195 count * sizeof *used);
2196 }
2197 old = vq->last_used_idx;
2198 new = (vq->last_used_idx += count);
2199 /* If the driver never bothers to signal in a very long while,
2200 * used index might wrap around. If that happens, invalidate
2201 * signalled_used index we stored. TODO: make sure driver
2202 * signals at least once in 2^16 and remove this. */
2203 if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old)))
2204 vq->signalled_used_valid = false;
2205 return 0;
2206 }
2207
2208 /* After we've used one of their buffers, we tell them about it. We'll then
2209 * want to notify the guest, using eventfd. */
2210 int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
2211 unsigned count)
2212 {
2213 int start, n, r;
2214
2215 start = vq->last_used_idx & (vq->num - 1);
2216 n = vq->num - start;
2217 if (n < count) {
2218 r = __vhost_add_used_n(vq, heads, n);
2219 if (r < 0)
2220 return r;
2221 heads += n;
2222 count -= n;
2223 }
2224 r = __vhost_add_used_n(vq, heads, count);
2225
2226 /* Make sure buffer is written before we update index. */
2227 smp_wmb();
2228 if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx),
2229 &vq->used->idx)) {
2230 vq_err(vq, "Failed to increment used idx");
2231 return -EFAULT;
2232 }
2233 if (unlikely(vq->log_used)) {
2234 /* Log used index update. */
2235 log_write(vq->log_base,
2236 vq->log_addr + offsetof(struct vring_used, idx),
2237 sizeof vq->used->idx);
2238 if (vq->log_ctx)
2239 eventfd_signal(vq->log_ctx, 1);
2240 }
2241 return r;
2242 }
2243 EXPORT_SYMBOL_GPL(vhost_add_used_n);
2244
2245 static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2246 {
2247 __u16 old, new;
2248 __virtio16 event;
2249 bool v;
2250 /* Flush out used index updates. This is paired
2251 * with the barrier that the Guest executes when enabling
2252 * interrupts. */
2253 smp_mb();
2254
2255 if (vhost_has_feature(vq, VIRTIO_F_NOTIFY_ON_EMPTY) &&
2256 unlikely(vq->avail_idx == vq->last_avail_idx))
2257 return true;
2258
2259 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2260 __virtio16 flags;
2261 if (vhost_get_avail(vq, flags, &vq->avail->flags)) {
2262 vq_err(vq, "Failed to get flags");
2263 return true;
2264 }
2265 return !(flags & cpu_to_vhost16(vq, VRING_AVAIL_F_NO_INTERRUPT));
2266 }
2267 old = vq->signalled_used;
2268 v = vq->signalled_used_valid;
2269 new = vq->signalled_used = vq->last_used_idx;
2270 vq->signalled_used_valid = true;
2271
2272 if (unlikely(!v))
2273 return true;
2274
2275 if (vhost_get_avail(vq, event, vhost_used_event(vq))) {
2276 vq_err(vq, "Failed to get used event idx");
2277 return true;
2278 }
2279 return vring_need_event(vhost16_to_cpu(vq, event), new, old);
2280 }
2281
2282 /* This actually signals the guest, using eventfd. */
2283 void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2284 {
2285 /* Signal the Guest tell them we used something up. */
2286 if (vq->call_ctx && vhost_notify(dev, vq))
2287 eventfd_signal(vq->call_ctx, 1);
2288 }
2289 EXPORT_SYMBOL_GPL(vhost_signal);
2290
2291 /* And here's the combo meal deal. Supersize me! */
2292 void vhost_add_used_and_signal(struct vhost_dev *dev,
2293 struct vhost_virtqueue *vq,
2294 unsigned int head, int len)
2295 {
2296 vhost_add_used(vq, head, len);
2297 vhost_signal(dev, vq);
2298 }
2299 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal);
2300
2301 /* multi-buffer version of vhost_add_used_and_signal */
2302 void vhost_add_used_and_signal_n(struct vhost_dev *dev,
2303 struct vhost_virtqueue *vq,
2304 struct vring_used_elem *heads, unsigned count)
2305 {
2306 vhost_add_used_n(vq, heads, count);
2307 vhost_signal(dev, vq);
2308 }
2309 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
2310
2311 /* return true if we're sure that avaiable ring is empty */
2312 bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2313 {
2314 __virtio16 avail_idx;
2315 int r;
2316
2317 if (vq->avail_idx != vq->last_avail_idx)
2318 return false;
2319
2320 r = vhost_get_avail(vq, avail_idx, &vq->avail->idx);
2321 if (unlikely(r))
2322 return false;
2323 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2324
2325 return vq->avail_idx == vq->last_avail_idx;
2326 }
2327 EXPORT_SYMBOL_GPL(vhost_vq_avail_empty);
2328
2329 /* OK, now we need to know about added descriptors. */
2330 bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2331 {
2332 __virtio16 avail_idx;
2333 int r;
2334
2335 if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
2336 return false;
2337 vq->used_flags &= ~VRING_USED_F_NO_NOTIFY;
2338 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2339 r = vhost_update_used_flags(vq);
2340 if (r) {
2341 vq_err(vq, "Failed to enable notification at %p: %d\n",
2342 &vq->used->flags, r);
2343 return false;
2344 }
2345 } else {
2346 r = vhost_update_avail_event(vq, vq->avail_idx);
2347 if (r) {
2348 vq_err(vq, "Failed to update avail event index at %p: %d\n",
2349 vhost_avail_event(vq), r);
2350 return false;
2351 }
2352 }
2353 /* They could have slipped one in as we were doing that: make
2354 * sure it's written, then check again. */
2355 smp_mb();
2356 r = vhost_get_avail(vq, avail_idx, &vq->avail->idx);
2357 if (r) {
2358 vq_err(vq, "Failed to check avail idx at %p: %d\n",
2359 &vq->avail->idx, r);
2360 return false;
2361 }
2362
2363 return vhost16_to_cpu(vq, avail_idx) != vq->avail_idx;
2364 }
2365 EXPORT_SYMBOL_GPL(vhost_enable_notify);
2366
2367 /* We don't need to be notified again. */
2368 void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2369 {
2370 int r;
2371
2372 if (vq->used_flags & VRING_USED_F_NO_NOTIFY)
2373 return;
2374 vq->used_flags |= VRING_USED_F_NO_NOTIFY;
2375 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2376 r = vhost_update_used_flags(vq);
2377 if (r)
2378 vq_err(vq, "Failed to enable notification at %p: %d\n",
2379 &vq->used->flags, r);
2380 }
2381 }
2382 EXPORT_SYMBOL_GPL(vhost_disable_notify);
2383
2384 /* Create a new message. */
2385 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type)
2386 {
2387 struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL);
2388 if (!node)
2389 return NULL;
2390
2391 /* Make sure all padding within the structure is initialized. */
2392 memset(&node->msg, 0, sizeof node->msg);
2393 node->vq = vq;
2394 node->msg.type = type;
2395 return node;
2396 }
2397 EXPORT_SYMBOL_GPL(vhost_new_msg);
2398
2399 void vhost_enqueue_msg(struct vhost_dev *dev, struct list_head *head,
2400 struct vhost_msg_node *node)
2401 {
2402 spin_lock(&dev->iotlb_lock);
2403 list_add_tail(&node->node, head);
2404 spin_unlock(&dev->iotlb_lock);
2405
2406 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
2407 }
2408 EXPORT_SYMBOL_GPL(vhost_enqueue_msg);
2409
2410 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
2411 struct list_head *head)
2412 {
2413 struct vhost_msg_node *node = NULL;
2414
2415 spin_lock(&dev->iotlb_lock);
2416 if (!list_empty(head)) {
2417 node = list_first_entry(head, struct vhost_msg_node,
2418 node);
2419 list_del(&node->node);
2420 }
2421 spin_unlock(&dev->iotlb_lock);
2422
2423 return node;
2424 }
2425 EXPORT_SYMBOL_GPL(vhost_dequeue_msg);
2426
2427
2428 static int __init vhost_init(void)
2429 {
2430 return 0;
2431 }
2432
2433 static void __exit vhost_exit(void)
2434 {
2435 }
2436
2437 module_init(vhost_init);
2438 module_exit(vhost_exit);
2439
2440 MODULE_VERSION("0.0.1");
2441 MODULE_LICENSE("GPL v2");
2442 MODULE_AUTHOR("Michael S. Tsirkin");
2443 MODULE_DESCRIPTION("Host kernel accelerator for virtio");
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