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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/miscdevice.h>
18#include <linux/mutex.h>
19#include <linux/poll.h>
20#include <linux/file.h>
21#include <linux/highmem.h>
22#include <linux/slab.h>
23#include <linux/vmalloc.h>
24#include <linux/kthread.h>
25#include <linux/module.h>
26#include <linux/sort.h>
27#include <linux/sched/mm.h>
28#include <linux/sched/signal.h>
29#include <linux/sched/vhost_task.h>
30#include <linux/interval_tree_generic.h>
31#include <linux/nospec.h>
32#include <linux/kcov.h>
33
34#include "vhost.h"
35
36static ushort max_mem_regions = 64;
37module_param(max_mem_regions, ushort, 0444);
38MODULE_PARM_DESC(max_mem_regions,
39 "Maximum number of memory regions in memory map. (default: 64)");
40static int max_iotlb_entries = 2048;
41module_param(max_iotlb_entries, int, 0444);
42MODULE_PARM_DESC(max_iotlb_entries,
43 "Maximum number of iotlb entries. (default: 2048)");
44
45enum {
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#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
53static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
54{
55 vq->user_be = !virtio_legacy_is_little_endian();
56}
57
58static void vhost_enable_cross_endian_big(struct vhost_virtqueue *vq)
59{
60 vq->user_be = true;
61}
62
63static void vhost_enable_cross_endian_little(struct vhost_virtqueue *vq)
64{
65 vq->user_be = false;
66}
67
68static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
69{
70 struct vhost_vring_state s;
71
72 if (vq->private_data)
73 return -EBUSY;
74
75 if (copy_from_user(&s, argp, sizeof(s)))
76 return -EFAULT;
77
78 if (s.num != VHOST_VRING_LITTLE_ENDIAN &&
79 s.num != VHOST_VRING_BIG_ENDIAN)
80 return -EINVAL;
81
82 if (s.num == VHOST_VRING_BIG_ENDIAN)
83 vhost_enable_cross_endian_big(vq);
84 else
85 vhost_enable_cross_endian_little(vq);
86
87 return 0;
88}
89
90static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
91 int __user *argp)
92{
93 struct vhost_vring_state s = {
94 .index = idx,
95 .num = vq->user_be
96 };
97
98 if (copy_to_user(argp, &s, sizeof(s)))
99 return -EFAULT;
100
101 return 0;
102}
103
104static void vhost_init_is_le(struct vhost_virtqueue *vq)
105{
106 /* Note for legacy virtio: user_be is initialized at reset time
107 * according to the host endianness. If userspace does not set an
108 * explicit endianness, the default behavior is native endian, as
109 * expected by legacy virtio.
110 */
111 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1) || !vq->user_be;
112}
113#else
114static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
115{
116}
117
118static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
119{
120 return -ENOIOCTLCMD;
121}
122
123static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
124 int __user *argp)
125{
126 return -ENOIOCTLCMD;
127}
128
129static void vhost_init_is_le(struct vhost_virtqueue *vq)
130{
131 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1)
132 || virtio_legacy_is_little_endian();
133}
134#endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
135
136static void vhost_reset_is_le(struct vhost_virtqueue *vq)
137{
138 vhost_init_is_le(vq);
139}
140
141struct vhost_flush_struct {
142 struct vhost_work work;
143 struct completion wait_event;
144};
145
146static void vhost_flush_work(struct vhost_work *work)
147{
148 struct vhost_flush_struct *s;
149
150 s = container_of(work, struct vhost_flush_struct, work);
151 complete(&s->wait_event);
152}
153
154static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
155 poll_table *pt)
156{
157 struct vhost_poll *poll;
158
159 poll = container_of(pt, struct vhost_poll, table);
160 poll->wqh = wqh;
161 add_wait_queue(wqh, &poll->wait);
162}
163
164static int vhost_poll_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync,
165 void *key)
166{
167 struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait);
168 struct vhost_work *work = &poll->work;
169
170 if (!(key_to_poll(key) & poll->mask))
171 return 0;
172
173 if (!poll->dev->use_worker)
174 work->fn(work);
175 else
176 vhost_poll_queue(poll);
177
178 return 0;
179}
180
181void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn)
182{
183 clear_bit(VHOST_WORK_QUEUED, &work->flags);
184 work->fn = fn;
185}
186EXPORT_SYMBOL_GPL(vhost_work_init);
187
188/* Init poll structure */
189void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
190 __poll_t mask, struct vhost_dev *dev,
191 struct vhost_virtqueue *vq)
192{
193 init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup);
194 init_poll_funcptr(&poll->table, vhost_poll_func);
195 poll->mask = mask;
196 poll->dev = dev;
197 poll->wqh = NULL;
198 poll->vq = vq;
199
200 vhost_work_init(&poll->work, fn);
201}
202EXPORT_SYMBOL_GPL(vhost_poll_init);
203
204/* Start polling a file. We add ourselves to file's wait queue. The caller must
205 * keep a reference to a file until after vhost_poll_stop is called. */
206int vhost_poll_start(struct vhost_poll *poll, struct file *file)
207{
208 __poll_t mask;
209
210 if (poll->wqh)
211 return 0;
212
213 mask = vfs_poll(file, &poll->table);
214 if (mask)
215 vhost_poll_wakeup(&poll->wait, 0, 0, poll_to_key(mask));
216 if (mask & EPOLLERR) {
217 vhost_poll_stop(poll);
218 return -EINVAL;
219 }
220
221 return 0;
222}
223EXPORT_SYMBOL_GPL(vhost_poll_start);
224
225/* Stop polling a file. After this function returns, it becomes safe to drop the
226 * file reference. You must also flush afterwards. */
227void vhost_poll_stop(struct vhost_poll *poll)
228{
229 if (poll->wqh) {
230 remove_wait_queue(poll->wqh, &poll->wait);
231 poll->wqh = NULL;
232 }
233}
234EXPORT_SYMBOL_GPL(vhost_poll_stop);
235
236static void vhost_worker_queue(struct vhost_worker *worker,
237 struct vhost_work *work)
238{
239 if (!test_and_set_bit(VHOST_WORK_QUEUED, &work->flags)) {
240 /* We can only add the work to the list after we're
241 * sure it was not in the list.
242 * test_and_set_bit() implies a memory barrier.
243 */
244 llist_add(&work->node, &worker->work_list);
245 vhost_task_wake(worker->vtsk);
246 }
247}
248
249bool vhost_vq_work_queue(struct vhost_virtqueue *vq, struct vhost_work *work)
250{
251 struct vhost_worker *worker;
252 bool queued = false;
253
254 rcu_read_lock();
255 worker = rcu_dereference(vq->worker);
256 if (worker) {
257 queued = true;
258 vhost_worker_queue(worker, work);
259 }
260 rcu_read_unlock();
261
262 return queued;
263}
264EXPORT_SYMBOL_GPL(vhost_vq_work_queue);
265
266void vhost_vq_flush(struct vhost_virtqueue *vq)
267{
268 struct vhost_flush_struct flush;
269
270 init_completion(&flush.wait_event);
271 vhost_work_init(&flush.work, vhost_flush_work);
272
273 if (vhost_vq_work_queue(vq, &flush.work))
274 wait_for_completion(&flush.wait_event);
275}
276EXPORT_SYMBOL_GPL(vhost_vq_flush);
277
278/**
279 * vhost_worker_flush - flush a worker
280 * @worker: worker to flush
281 *
282 * This does not use RCU to protect the worker, so the device or worker
283 * mutex must be held.
284 */
285static void vhost_worker_flush(struct vhost_worker *worker)
286{
287 struct vhost_flush_struct flush;
288
289 init_completion(&flush.wait_event);
290 vhost_work_init(&flush.work, vhost_flush_work);
291
292 vhost_worker_queue(worker, &flush.work);
293 wait_for_completion(&flush.wait_event);
294}
295
296void vhost_dev_flush(struct vhost_dev *dev)
297{
298 struct vhost_worker *worker;
299 unsigned long i;
300
301 xa_for_each(&dev->worker_xa, i, worker) {
302 mutex_lock(&worker->mutex);
303 if (!worker->attachment_cnt) {
304 mutex_unlock(&worker->mutex);
305 continue;
306 }
307 vhost_worker_flush(worker);
308 mutex_unlock(&worker->mutex);
309 }
310}
311EXPORT_SYMBOL_GPL(vhost_dev_flush);
312
313/* A lockless hint for busy polling code to exit the loop */
314bool vhost_vq_has_work(struct vhost_virtqueue *vq)
315{
316 struct vhost_worker *worker;
317 bool has_work = false;
318
319 rcu_read_lock();
320 worker = rcu_dereference(vq->worker);
321 if (worker && !llist_empty(&worker->work_list))
322 has_work = true;
323 rcu_read_unlock();
324
325 return has_work;
326}
327EXPORT_SYMBOL_GPL(vhost_vq_has_work);
328
329void vhost_poll_queue(struct vhost_poll *poll)
330{
331 vhost_vq_work_queue(poll->vq, &poll->work);
332}
333EXPORT_SYMBOL_GPL(vhost_poll_queue);
334
335static void __vhost_vq_meta_reset(struct vhost_virtqueue *vq)
336{
337 int j;
338
339 for (j = 0; j < VHOST_NUM_ADDRS; j++)
340 vq->meta_iotlb[j] = NULL;
341}
342
343static void vhost_vq_meta_reset(struct vhost_dev *d)
344{
345 int i;
346
347 for (i = 0; i < d->nvqs; ++i)
348 __vhost_vq_meta_reset(d->vqs[i]);
349}
350
351static void vhost_vring_call_reset(struct vhost_vring_call *call_ctx)
352{
353 call_ctx->ctx = NULL;
354 memset(&call_ctx->producer, 0x0, sizeof(struct irq_bypass_producer));
355}
356
357bool vhost_vq_is_setup(struct vhost_virtqueue *vq)
358{
359 return vq->avail && vq->desc && vq->used && vhost_vq_access_ok(vq);
360}
361EXPORT_SYMBOL_GPL(vhost_vq_is_setup);
362
363static void vhost_vq_reset(struct vhost_dev *dev,
364 struct vhost_virtqueue *vq)
365{
366 vq->num = 1;
367 vq->desc = NULL;
368 vq->avail = NULL;
369 vq->used = NULL;
370 vq->last_avail_idx = 0;
371 vq->avail_idx = 0;
372 vq->last_used_idx = 0;
373 vq->signalled_used = 0;
374 vq->signalled_used_valid = false;
375 vq->used_flags = 0;
376 vq->log_used = false;
377 vq->log_addr = -1ull;
378 vq->private_data = NULL;
379 vq->acked_features = 0;
380 vq->acked_backend_features = 0;
381 vq->log_base = NULL;
382 vq->error_ctx = NULL;
383 vq->kick = NULL;
384 vq->log_ctx = NULL;
385 vhost_disable_cross_endian(vq);
386 vhost_reset_is_le(vq);
387 vq->busyloop_timeout = 0;
388 vq->umem = NULL;
389 vq->iotlb = NULL;
390 rcu_assign_pointer(vq->worker, NULL);
391 vhost_vring_call_reset(&vq->call_ctx);
392 __vhost_vq_meta_reset(vq);
393}
394
395static bool vhost_worker(void *data)
396{
397 struct vhost_worker *worker = data;
398 struct vhost_work *work, *work_next;
399 struct llist_node *node;
400
401 node = llist_del_all(&worker->work_list);
402 if (node) {
403 __set_current_state(TASK_RUNNING);
404
405 node = llist_reverse_order(node);
406 /* make sure flag is seen after deletion */
407 smp_wmb();
408 llist_for_each_entry_safe(work, work_next, node, node) {
409 clear_bit(VHOST_WORK_QUEUED, &work->flags);
410 kcov_remote_start_common(worker->kcov_handle);
411 work->fn(work);
412 kcov_remote_stop();
413 cond_resched();
414 }
415 }
416
417 return !!node;
418}
419
420static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq)
421{
422 kfree(vq->indirect);
423 vq->indirect = NULL;
424 kfree(vq->log);
425 vq->log = NULL;
426 kfree(vq->heads);
427 vq->heads = NULL;
428}
429
430/* Helper to allocate iovec buffers for all vqs. */
431static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
432{
433 struct vhost_virtqueue *vq;
434 int i;
435
436 for (i = 0; i < dev->nvqs; ++i) {
437 vq = dev->vqs[i];
438 vq->indirect = kmalloc_array(UIO_MAXIOV,
439 sizeof(*vq->indirect),
440 GFP_KERNEL);
441 vq->log = kmalloc_array(dev->iov_limit, sizeof(*vq->log),
442 GFP_KERNEL);
443 vq->heads = kmalloc_array(dev->iov_limit, sizeof(*vq->heads),
444 GFP_KERNEL);
445 if (!vq->indirect || !vq->log || !vq->heads)
446 goto err_nomem;
447 }
448 return 0;
449
450err_nomem:
451 for (; i >= 0; --i)
452 vhost_vq_free_iovecs(dev->vqs[i]);
453 return -ENOMEM;
454}
455
456static void vhost_dev_free_iovecs(struct vhost_dev *dev)
457{
458 int i;
459
460 for (i = 0; i < dev->nvqs; ++i)
461 vhost_vq_free_iovecs(dev->vqs[i]);
462}
463
464bool vhost_exceeds_weight(struct vhost_virtqueue *vq,
465 int pkts, int total_len)
466{
467 struct vhost_dev *dev = vq->dev;
468
469 if ((dev->byte_weight && total_len >= dev->byte_weight) ||
470 pkts >= dev->weight) {
471 vhost_poll_queue(&vq->poll);
472 return true;
473 }
474
475 return false;
476}
477EXPORT_SYMBOL_GPL(vhost_exceeds_weight);
478
479static size_t vhost_get_avail_size(struct vhost_virtqueue *vq,
480 unsigned int num)
481{
482 size_t event __maybe_unused =
483 vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
484
485 return size_add(struct_size(vq->avail, ring, num), event);
486}
487
488static size_t vhost_get_used_size(struct vhost_virtqueue *vq,
489 unsigned int num)
490{
491 size_t event __maybe_unused =
492 vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
493
494 return size_add(struct_size(vq->used, ring, num), event);
495}
496
497static size_t vhost_get_desc_size(struct vhost_virtqueue *vq,
498 unsigned int num)
499{
500 return sizeof(*vq->desc) * num;
501}
502
503void vhost_dev_init(struct vhost_dev *dev,
504 struct vhost_virtqueue **vqs, int nvqs,
505 int iov_limit, int weight, int byte_weight,
506 bool use_worker,
507 int (*msg_handler)(struct vhost_dev *dev, u32 asid,
508 struct vhost_iotlb_msg *msg))
509{
510 struct vhost_virtqueue *vq;
511 int i;
512
513 dev->vqs = vqs;
514 dev->nvqs = nvqs;
515 mutex_init(&dev->mutex);
516 dev->log_ctx = NULL;
517 dev->umem = NULL;
518 dev->iotlb = NULL;
519 dev->mm = NULL;
520 dev->iov_limit = iov_limit;
521 dev->weight = weight;
522 dev->byte_weight = byte_weight;
523 dev->use_worker = use_worker;
524 dev->msg_handler = msg_handler;
525 init_waitqueue_head(&dev->wait);
526 INIT_LIST_HEAD(&dev->read_list);
527 INIT_LIST_HEAD(&dev->pending_list);
528 spin_lock_init(&dev->iotlb_lock);
529 xa_init_flags(&dev->worker_xa, XA_FLAGS_ALLOC);
530
531 for (i = 0; i < dev->nvqs; ++i) {
532 vq = dev->vqs[i];
533 vq->log = NULL;
534 vq->indirect = NULL;
535 vq->heads = NULL;
536 vq->dev = dev;
537 mutex_init(&vq->mutex);
538 vhost_vq_reset(dev, vq);
539 if (vq->handle_kick)
540 vhost_poll_init(&vq->poll, vq->handle_kick,
541 EPOLLIN, dev, vq);
542 }
543}
544EXPORT_SYMBOL_GPL(vhost_dev_init);
545
546/* Caller should have device mutex */
547long vhost_dev_check_owner(struct vhost_dev *dev)
548{
549 /* Are you the owner? If not, I don't think you mean to do that */
550 return dev->mm == current->mm ? 0 : -EPERM;
551}
552EXPORT_SYMBOL_GPL(vhost_dev_check_owner);
553
554/* Caller should have device mutex */
555bool vhost_dev_has_owner(struct vhost_dev *dev)
556{
557 return dev->mm;
558}
559EXPORT_SYMBOL_GPL(vhost_dev_has_owner);
560
561static void vhost_attach_mm(struct vhost_dev *dev)
562{
563 /* No owner, become one */
564 if (dev->use_worker) {
565 dev->mm = get_task_mm(current);
566 } else {
567 /* vDPA device does not use worker thead, so there's
568 * no need to hold the address space for mm. This help
569 * to avoid deadlock in the case of mmap() which may
570 * held the refcnt of the file and depends on release
571 * method to remove vma.
572 */
573 dev->mm = current->mm;
574 mmgrab(dev->mm);
575 }
576}
577
578static void vhost_detach_mm(struct vhost_dev *dev)
579{
580 if (!dev->mm)
581 return;
582
583 if (dev->use_worker)
584 mmput(dev->mm);
585 else
586 mmdrop(dev->mm);
587
588 dev->mm = NULL;
589}
590
591static void vhost_worker_destroy(struct vhost_dev *dev,
592 struct vhost_worker *worker)
593{
594 if (!worker)
595 return;
596
597 WARN_ON(!llist_empty(&worker->work_list));
598 xa_erase(&dev->worker_xa, worker->id);
599 vhost_task_stop(worker->vtsk);
600 kfree(worker);
601}
602
603static void vhost_workers_free(struct vhost_dev *dev)
604{
605 struct vhost_worker *worker;
606 unsigned long i;
607
608 if (!dev->use_worker)
609 return;
610
611 for (i = 0; i < dev->nvqs; i++)
612 rcu_assign_pointer(dev->vqs[i]->worker, NULL);
613 /*
614 * Free the default worker we created and cleanup workers userspace
615 * created but couldn't clean up (it forgot or crashed).
616 */
617 xa_for_each(&dev->worker_xa, i, worker)
618 vhost_worker_destroy(dev, worker);
619 xa_destroy(&dev->worker_xa);
620}
621
622static struct vhost_worker *vhost_worker_create(struct vhost_dev *dev)
623{
624 struct vhost_worker *worker;
625 struct vhost_task *vtsk;
626 char name[TASK_COMM_LEN];
627 int ret;
628 u32 id;
629
630 worker = kzalloc(sizeof(*worker), GFP_KERNEL_ACCOUNT);
631 if (!worker)
632 return NULL;
633
634 snprintf(name, sizeof(name), "vhost-%d", current->pid);
635
636 vtsk = vhost_task_create(vhost_worker, worker, name);
637 if (!vtsk)
638 goto free_worker;
639
640 mutex_init(&worker->mutex);
641 init_llist_head(&worker->work_list);
642 worker->kcov_handle = kcov_common_handle();
643 worker->vtsk = vtsk;
644
645 vhost_task_start(vtsk);
646
647 ret = xa_alloc(&dev->worker_xa, &id, worker, xa_limit_32b, GFP_KERNEL);
648 if (ret < 0)
649 goto stop_worker;
650 worker->id = id;
651
652 return worker;
653
654stop_worker:
655 vhost_task_stop(vtsk);
656free_worker:
657 kfree(worker);
658 return NULL;
659}
660
661/* Caller must have device mutex */
662static void __vhost_vq_attach_worker(struct vhost_virtqueue *vq,
663 struct vhost_worker *worker)
664{
665 struct vhost_worker *old_worker;
666
667 old_worker = rcu_dereference_check(vq->worker,
668 lockdep_is_held(&vq->dev->mutex));
669
670 mutex_lock(&worker->mutex);
671 worker->attachment_cnt++;
672 mutex_unlock(&worker->mutex);
673 rcu_assign_pointer(vq->worker, worker);
674
675 if (!old_worker)
676 return;
677 /*
678 * Take the worker mutex to make sure we see the work queued from
679 * device wide flushes which doesn't use RCU for execution.
680 */
681 mutex_lock(&old_worker->mutex);
682 old_worker->attachment_cnt--;
683 /*
684 * We don't want to call synchronize_rcu for every vq during setup
685 * because it will slow down VM startup. If we haven't done
686 * VHOST_SET_VRING_KICK and not done the driver specific
687 * SET_ENDPOINT/RUNNUNG then we can skip the sync since there will
688 * not be any works queued for scsi and net.
689 */
690 mutex_lock(&vq->mutex);
691 if (!vhost_vq_get_backend(vq) && !vq->kick) {
692 mutex_unlock(&vq->mutex);
693 mutex_unlock(&old_worker->mutex);
694 /*
695 * vsock can queue anytime after VHOST_VSOCK_SET_GUEST_CID.
696 * Warn if it adds support for multiple workers but forgets to
697 * handle the early queueing case.
698 */
699 WARN_ON(!old_worker->attachment_cnt &&
700 !llist_empty(&old_worker->work_list));
701 return;
702 }
703 mutex_unlock(&vq->mutex);
704
705 /* Make sure new vq queue/flush/poll calls see the new worker */
706 synchronize_rcu();
707 /* Make sure whatever was queued gets run */
708 vhost_worker_flush(old_worker);
709 mutex_unlock(&old_worker->mutex);
710}
711
712 /* Caller must have device mutex */
713static int vhost_vq_attach_worker(struct vhost_virtqueue *vq,
714 struct vhost_vring_worker *info)
715{
716 unsigned long index = info->worker_id;
717 struct vhost_dev *dev = vq->dev;
718 struct vhost_worker *worker;
719
720 if (!dev->use_worker)
721 return -EINVAL;
722
723 worker = xa_find(&dev->worker_xa, &index, UINT_MAX, XA_PRESENT);
724 if (!worker || worker->id != info->worker_id)
725 return -ENODEV;
726
727 __vhost_vq_attach_worker(vq, worker);
728 return 0;
729}
730
731/* Caller must have device mutex */
732static int vhost_new_worker(struct vhost_dev *dev,
733 struct vhost_worker_state *info)
734{
735 struct vhost_worker *worker;
736
737 worker = vhost_worker_create(dev);
738 if (!worker)
739 return -ENOMEM;
740
741 info->worker_id = worker->id;
742 return 0;
743}
744
745/* Caller must have device mutex */
746static int vhost_free_worker(struct vhost_dev *dev,
747 struct vhost_worker_state *info)
748{
749 unsigned long index = info->worker_id;
750 struct vhost_worker *worker;
751
752 worker = xa_find(&dev->worker_xa, &index, UINT_MAX, XA_PRESENT);
753 if (!worker || worker->id != info->worker_id)
754 return -ENODEV;
755
756 mutex_lock(&worker->mutex);
757 if (worker->attachment_cnt) {
758 mutex_unlock(&worker->mutex);
759 return -EBUSY;
760 }
761 mutex_unlock(&worker->mutex);
762
763 vhost_worker_destroy(dev, worker);
764 return 0;
765}
766
767static int vhost_get_vq_from_user(struct vhost_dev *dev, void __user *argp,
768 struct vhost_virtqueue **vq, u32 *id)
769{
770 u32 __user *idxp = argp;
771 u32 idx;
772 long r;
773
774 r = get_user(idx, idxp);
775 if (r < 0)
776 return r;
777
778 if (idx >= dev->nvqs)
779 return -ENOBUFS;
780
781 idx = array_index_nospec(idx, dev->nvqs);
782
783 *vq = dev->vqs[idx];
784 *id = idx;
785 return 0;
786}
787
788/* Caller must have device mutex */
789long vhost_worker_ioctl(struct vhost_dev *dev, unsigned int ioctl,
790 void __user *argp)
791{
792 struct vhost_vring_worker ring_worker;
793 struct vhost_worker_state state;
794 struct vhost_worker *worker;
795 struct vhost_virtqueue *vq;
796 long ret;
797 u32 idx;
798
799 if (!dev->use_worker)
800 return -EINVAL;
801
802 if (!vhost_dev_has_owner(dev))
803 return -EINVAL;
804
805 ret = vhost_dev_check_owner(dev);
806 if (ret)
807 return ret;
808
809 switch (ioctl) {
810 /* dev worker ioctls */
811 case VHOST_NEW_WORKER:
812 ret = vhost_new_worker(dev, &state);
813 if (!ret && copy_to_user(argp, &state, sizeof(state)))
814 ret = -EFAULT;
815 return ret;
816 case VHOST_FREE_WORKER:
817 if (copy_from_user(&state, argp, sizeof(state)))
818 return -EFAULT;
819 return vhost_free_worker(dev, &state);
820 /* vring worker ioctls */
821 case VHOST_ATTACH_VRING_WORKER:
822 case VHOST_GET_VRING_WORKER:
823 break;
824 default:
825 return -ENOIOCTLCMD;
826 }
827
828 ret = vhost_get_vq_from_user(dev, argp, &vq, &idx);
829 if (ret)
830 return ret;
831
832 switch (ioctl) {
833 case VHOST_ATTACH_VRING_WORKER:
834 if (copy_from_user(&ring_worker, argp, sizeof(ring_worker))) {
835 ret = -EFAULT;
836 break;
837 }
838
839 ret = vhost_vq_attach_worker(vq, &ring_worker);
840 break;
841 case VHOST_GET_VRING_WORKER:
842 worker = rcu_dereference_check(vq->worker,
843 lockdep_is_held(&dev->mutex));
844 if (!worker) {
845 ret = -EINVAL;
846 break;
847 }
848
849 ring_worker.index = idx;
850 ring_worker.worker_id = worker->id;
851
852 if (copy_to_user(argp, &ring_worker, sizeof(ring_worker)))
853 ret = -EFAULT;
854 break;
855 default:
856 ret = -ENOIOCTLCMD;
857 break;
858 }
859
860 return ret;
861}
862EXPORT_SYMBOL_GPL(vhost_worker_ioctl);
863
864/* Caller should have device mutex */
865long vhost_dev_set_owner(struct vhost_dev *dev)
866{
867 struct vhost_worker *worker;
868 int err, i;
869
870 /* Is there an owner already? */
871 if (vhost_dev_has_owner(dev)) {
872 err = -EBUSY;
873 goto err_mm;
874 }
875
876 vhost_attach_mm(dev);
877
878 err = vhost_dev_alloc_iovecs(dev);
879 if (err)
880 goto err_iovecs;
881
882 if (dev->use_worker) {
883 /*
884 * This should be done last, because vsock can queue work
885 * before VHOST_SET_OWNER so it simplifies the failure path
886 * below since we don't have to worry about vsock queueing
887 * while we free the worker.
888 */
889 worker = vhost_worker_create(dev);
890 if (!worker) {
891 err = -ENOMEM;
892 goto err_worker;
893 }
894
895 for (i = 0; i < dev->nvqs; i++)
896 __vhost_vq_attach_worker(dev->vqs[i], worker);
897 }
898
899 return 0;
900
901err_worker:
902 vhost_dev_free_iovecs(dev);
903err_iovecs:
904 vhost_detach_mm(dev);
905err_mm:
906 return err;
907}
908EXPORT_SYMBOL_GPL(vhost_dev_set_owner);
909
910static struct vhost_iotlb *iotlb_alloc(void)
911{
912 return vhost_iotlb_alloc(max_iotlb_entries,
913 VHOST_IOTLB_FLAG_RETIRE);
914}
915
916struct vhost_iotlb *vhost_dev_reset_owner_prepare(void)
917{
918 return iotlb_alloc();
919}
920EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare);
921
922/* Caller should have device mutex */
923void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_iotlb *umem)
924{
925 int i;
926
927 vhost_dev_cleanup(dev);
928
929 dev->umem = umem;
930 /* We don't need VQ locks below since vhost_dev_cleanup makes sure
931 * VQs aren't running.
932 */
933 for (i = 0; i < dev->nvqs; ++i)
934 dev->vqs[i]->umem = umem;
935}
936EXPORT_SYMBOL_GPL(vhost_dev_reset_owner);
937
938void vhost_dev_stop(struct vhost_dev *dev)
939{
940 int i;
941
942 for (i = 0; i < dev->nvqs; ++i) {
943 if (dev->vqs[i]->kick && dev->vqs[i]->handle_kick)
944 vhost_poll_stop(&dev->vqs[i]->poll);
945 }
946
947 vhost_dev_flush(dev);
948}
949EXPORT_SYMBOL_GPL(vhost_dev_stop);
950
951void vhost_clear_msg(struct vhost_dev *dev)
952{
953 struct vhost_msg_node *node, *n;
954
955 spin_lock(&dev->iotlb_lock);
956
957 list_for_each_entry_safe(node, n, &dev->read_list, node) {
958 list_del(&node->node);
959 kfree(node);
960 }
961
962 list_for_each_entry_safe(node, n, &dev->pending_list, node) {
963 list_del(&node->node);
964 kfree(node);
965 }
966
967 spin_unlock(&dev->iotlb_lock);
968}
969EXPORT_SYMBOL_GPL(vhost_clear_msg);
970
971void vhost_dev_cleanup(struct vhost_dev *dev)
972{
973 int i;
974
975 for (i = 0; i < dev->nvqs; ++i) {
976 if (dev->vqs[i]->error_ctx)
977 eventfd_ctx_put(dev->vqs[i]->error_ctx);
978 if (dev->vqs[i]->kick)
979 fput(dev->vqs[i]->kick);
980 if (dev->vqs[i]->call_ctx.ctx)
981 eventfd_ctx_put(dev->vqs[i]->call_ctx.ctx);
982 vhost_vq_reset(dev, dev->vqs[i]);
983 }
984 vhost_dev_free_iovecs(dev);
985 if (dev->log_ctx)
986 eventfd_ctx_put(dev->log_ctx);
987 dev->log_ctx = NULL;
988 /* No one will access memory at this point */
989 vhost_iotlb_free(dev->umem);
990 dev->umem = NULL;
991 vhost_iotlb_free(dev->iotlb);
992 dev->iotlb = NULL;
993 vhost_clear_msg(dev);
994 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
995 vhost_workers_free(dev);
996 vhost_detach_mm(dev);
997}
998EXPORT_SYMBOL_GPL(vhost_dev_cleanup);
999
1000static bool log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
1001{
1002 u64 a = addr / VHOST_PAGE_SIZE / 8;
1003
1004 /* Make sure 64 bit math will not overflow. */
1005 if (a > ULONG_MAX - (unsigned long)log_base ||
1006 a + (unsigned long)log_base > ULONG_MAX)
1007 return false;
1008
1009 return access_ok(log_base + a,
1010 (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8);
1011}
1012
1013/* Make sure 64 bit math will not overflow. */
1014static bool vhost_overflow(u64 uaddr, u64 size)
1015{
1016 if (uaddr > ULONG_MAX || size > ULONG_MAX)
1017 return true;
1018
1019 if (!size)
1020 return false;
1021
1022 return uaddr > ULONG_MAX - size + 1;
1023}
1024
1025/* Caller should have vq mutex and device mutex. */
1026static bool vq_memory_access_ok(void __user *log_base, struct vhost_iotlb *umem,
1027 int log_all)
1028{
1029 struct vhost_iotlb_map *map;
1030
1031 if (!umem)
1032 return false;
1033
1034 list_for_each_entry(map, &umem->list, link) {
1035 unsigned long a = map->addr;
1036
1037 if (vhost_overflow(map->addr, map->size))
1038 return false;
1039
1040
1041 if (!access_ok((void __user *)a, map->size))
1042 return false;
1043 else if (log_all && !log_access_ok(log_base,
1044 map->start,
1045 map->size))
1046 return false;
1047 }
1048 return true;
1049}
1050
1051static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq,
1052 u64 addr, unsigned int size,
1053 int type)
1054{
1055 const struct vhost_iotlb_map *map = vq->meta_iotlb[type];
1056
1057 if (!map)
1058 return NULL;
1059
1060 return (void __user *)(uintptr_t)(map->addr + addr - map->start);
1061}
1062
1063/* Can we switch to this memory table? */
1064/* Caller should have device mutex but not vq mutex */
1065static bool memory_access_ok(struct vhost_dev *d, struct vhost_iotlb *umem,
1066 int log_all)
1067{
1068 int i;
1069
1070 for (i = 0; i < d->nvqs; ++i) {
1071 bool ok;
1072 bool log;
1073
1074 mutex_lock(&d->vqs[i]->mutex);
1075 log = log_all || vhost_has_feature(d->vqs[i], VHOST_F_LOG_ALL);
1076 /* If ring is inactive, will check when it's enabled. */
1077 if (d->vqs[i]->private_data)
1078 ok = vq_memory_access_ok(d->vqs[i]->log_base,
1079 umem, log);
1080 else
1081 ok = true;
1082 mutex_unlock(&d->vqs[i]->mutex);
1083 if (!ok)
1084 return false;
1085 }
1086 return true;
1087}
1088
1089static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
1090 struct iovec iov[], int iov_size, int access);
1091
1092static int vhost_copy_to_user(struct vhost_virtqueue *vq, void __user *to,
1093 const void *from, unsigned size)
1094{
1095 int ret;
1096
1097 if (!vq->iotlb)
1098 return __copy_to_user(to, from, size);
1099 else {
1100 /* This function should be called after iotlb
1101 * prefetch, which means we're sure that all vq
1102 * could be access through iotlb. So -EAGAIN should
1103 * not happen in this case.
1104 */
1105 struct iov_iter t;
1106 void __user *uaddr = vhost_vq_meta_fetch(vq,
1107 (u64)(uintptr_t)to, size,
1108 VHOST_ADDR_USED);
1109
1110 if (uaddr)
1111 return __copy_to_user(uaddr, from, size);
1112
1113 ret = translate_desc(vq, (u64)(uintptr_t)to, size, vq->iotlb_iov,
1114 ARRAY_SIZE(vq->iotlb_iov),
1115 VHOST_ACCESS_WO);
1116 if (ret < 0)
1117 goto out;
1118 iov_iter_init(&t, ITER_DEST, vq->iotlb_iov, ret, size);
1119 ret = copy_to_iter(from, size, &t);
1120 if (ret == size)
1121 ret = 0;
1122 }
1123out:
1124 return ret;
1125}
1126
1127static int vhost_copy_from_user(struct vhost_virtqueue *vq, void *to,
1128 void __user *from, unsigned size)
1129{
1130 int ret;
1131
1132 if (!vq->iotlb)
1133 return __copy_from_user(to, from, size);
1134 else {
1135 /* This function should be called after iotlb
1136 * prefetch, which means we're sure that vq
1137 * could be access through iotlb. So -EAGAIN should
1138 * not happen in this case.
1139 */
1140 void __user *uaddr = vhost_vq_meta_fetch(vq,
1141 (u64)(uintptr_t)from, size,
1142 VHOST_ADDR_DESC);
1143 struct iov_iter f;
1144
1145 if (uaddr)
1146 return __copy_from_user(to, uaddr, size);
1147
1148 ret = translate_desc(vq, (u64)(uintptr_t)from, size, vq->iotlb_iov,
1149 ARRAY_SIZE(vq->iotlb_iov),
1150 VHOST_ACCESS_RO);
1151 if (ret < 0) {
1152 vq_err(vq, "IOTLB translation failure: uaddr "
1153 "%p size 0x%llx\n", from,
1154 (unsigned long long) size);
1155 goto out;
1156 }
1157 iov_iter_init(&f, ITER_SOURCE, vq->iotlb_iov, ret, size);
1158 ret = copy_from_iter(to, size, &f);
1159 if (ret == size)
1160 ret = 0;
1161 }
1162
1163out:
1164 return ret;
1165}
1166
1167static void __user *__vhost_get_user_slow(struct vhost_virtqueue *vq,
1168 void __user *addr, unsigned int size,
1169 int type)
1170{
1171 int ret;
1172
1173 ret = translate_desc(vq, (u64)(uintptr_t)addr, size, vq->iotlb_iov,
1174 ARRAY_SIZE(vq->iotlb_iov),
1175 VHOST_ACCESS_RO);
1176 if (ret < 0) {
1177 vq_err(vq, "IOTLB translation failure: uaddr "
1178 "%p size 0x%llx\n", addr,
1179 (unsigned long long) size);
1180 return NULL;
1181 }
1182
1183 if (ret != 1 || vq->iotlb_iov[0].iov_len != size) {
1184 vq_err(vq, "Non atomic userspace memory access: uaddr "
1185 "%p size 0x%llx\n", addr,
1186 (unsigned long long) size);
1187 return NULL;
1188 }
1189
1190 return vq->iotlb_iov[0].iov_base;
1191}
1192
1193/* This function should be called after iotlb
1194 * prefetch, which means we're sure that vq
1195 * could be access through iotlb. So -EAGAIN should
1196 * not happen in this case.
1197 */
1198static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq,
1199 void __user *addr, unsigned int size,
1200 int type)
1201{
1202 void __user *uaddr = vhost_vq_meta_fetch(vq,
1203 (u64)(uintptr_t)addr, size, type);
1204 if (uaddr)
1205 return uaddr;
1206
1207 return __vhost_get_user_slow(vq, addr, size, type);
1208}
1209
1210#define vhost_put_user(vq, x, ptr) \
1211({ \
1212 int ret; \
1213 if (!vq->iotlb) { \
1214 ret = __put_user(x, ptr); \
1215 } else { \
1216 __typeof__(ptr) to = \
1217 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
1218 sizeof(*ptr), VHOST_ADDR_USED); \
1219 if (to != NULL) \
1220 ret = __put_user(x, to); \
1221 else \
1222 ret = -EFAULT; \
1223 } \
1224 ret; \
1225})
1226
1227static inline int vhost_put_avail_event(struct vhost_virtqueue *vq)
1228{
1229 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx),
1230 vhost_avail_event(vq));
1231}
1232
1233static inline int vhost_put_used(struct vhost_virtqueue *vq,
1234 struct vring_used_elem *head, int idx,
1235 int count)
1236{
1237 return vhost_copy_to_user(vq, vq->used->ring + idx, head,
1238 count * sizeof(*head));
1239}
1240
1241static inline int vhost_put_used_flags(struct vhost_virtqueue *vq)
1242
1243{
1244 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags),
1245 &vq->used->flags);
1246}
1247
1248static inline int vhost_put_used_idx(struct vhost_virtqueue *vq)
1249
1250{
1251 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx),
1252 &vq->used->idx);
1253}
1254
1255#define vhost_get_user(vq, x, ptr, type) \
1256({ \
1257 int ret; \
1258 if (!vq->iotlb) { \
1259 ret = __get_user(x, ptr); \
1260 } else { \
1261 __typeof__(ptr) from = \
1262 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
1263 sizeof(*ptr), \
1264 type); \
1265 if (from != NULL) \
1266 ret = __get_user(x, from); \
1267 else \
1268 ret = -EFAULT; \
1269 } \
1270 ret; \
1271})
1272
1273#define vhost_get_avail(vq, x, ptr) \
1274 vhost_get_user(vq, x, ptr, VHOST_ADDR_AVAIL)
1275
1276#define vhost_get_used(vq, x, ptr) \
1277 vhost_get_user(vq, x, ptr, VHOST_ADDR_USED)
1278
1279static void vhost_dev_lock_vqs(struct vhost_dev *d)
1280{
1281 int i = 0;
1282 for (i = 0; i < d->nvqs; ++i)
1283 mutex_lock_nested(&d->vqs[i]->mutex, i);
1284}
1285
1286static void vhost_dev_unlock_vqs(struct vhost_dev *d)
1287{
1288 int i = 0;
1289 for (i = 0; i < d->nvqs; ++i)
1290 mutex_unlock(&d->vqs[i]->mutex);
1291}
1292
1293static inline int vhost_get_avail_idx(struct vhost_virtqueue *vq,
1294 __virtio16 *idx)
1295{
1296 return vhost_get_avail(vq, *idx, &vq->avail->idx);
1297}
1298
1299static inline int vhost_get_avail_head(struct vhost_virtqueue *vq,
1300 __virtio16 *head, int idx)
1301{
1302 return vhost_get_avail(vq, *head,
1303 &vq->avail->ring[idx & (vq->num - 1)]);
1304}
1305
1306static inline int vhost_get_avail_flags(struct vhost_virtqueue *vq,
1307 __virtio16 *flags)
1308{
1309 return vhost_get_avail(vq, *flags, &vq->avail->flags);
1310}
1311
1312static inline int vhost_get_used_event(struct vhost_virtqueue *vq,
1313 __virtio16 *event)
1314{
1315 return vhost_get_avail(vq, *event, vhost_used_event(vq));
1316}
1317
1318static inline int vhost_get_used_idx(struct vhost_virtqueue *vq,
1319 __virtio16 *idx)
1320{
1321 return vhost_get_used(vq, *idx, &vq->used->idx);
1322}
1323
1324static inline int vhost_get_desc(struct vhost_virtqueue *vq,
1325 struct vring_desc *desc, int idx)
1326{
1327 return vhost_copy_from_user(vq, desc, vq->desc + idx, sizeof(*desc));
1328}
1329
1330static void vhost_iotlb_notify_vq(struct vhost_dev *d,
1331 struct vhost_iotlb_msg *msg)
1332{
1333 struct vhost_msg_node *node, *n;
1334
1335 spin_lock(&d->iotlb_lock);
1336
1337 list_for_each_entry_safe(node, n, &d->pending_list, node) {
1338 struct vhost_iotlb_msg *vq_msg = &node->msg.iotlb;
1339 if (msg->iova <= vq_msg->iova &&
1340 msg->iova + msg->size - 1 >= vq_msg->iova &&
1341 vq_msg->type == VHOST_IOTLB_MISS) {
1342 vhost_poll_queue(&node->vq->poll);
1343 list_del(&node->node);
1344 kfree(node);
1345 }
1346 }
1347
1348 spin_unlock(&d->iotlb_lock);
1349}
1350
1351static bool umem_access_ok(u64 uaddr, u64 size, int access)
1352{
1353 unsigned long a = uaddr;
1354
1355 /* Make sure 64 bit math will not overflow. */
1356 if (vhost_overflow(uaddr, size))
1357 return false;
1358
1359 if ((access & VHOST_ACCESS_RO) &&
1360 !access_ok((void __user *)a, size))
1361 return false;
1362 if ((access & VHOST_ACCESS_WO) &&
1363 !access_ok((void __user *)a, size))
1364 return false;
1365 return true;
1366}
1367
1368static int vhost_process_iotlb_msg(struct vhost_dev *dev, u32 asid,
1369 struct vhost_iotlb_msg *msg)
1370{
1371 int ret = 0;
1372
1373 if (asid != 0)
1374 return -EINVAL;
1375
1376 mutex_lock(&dev->mutex);
1377 vhost_dev_lock_vqs(dev);
1378 switch (msg->type) {
1379 case VHOST_IOTLB_UPDATE:
1380 if (!dev->iotlb) {
1381 ret = -EFAULT;
1382 break;
1383 }
1384 if (!umem_access_ok(msg->uaddr, msg->size, msg->perm)) {
1385 ret = -EFAULT;
1386 break;
1387 }
1388 vhost_vq_meta_reset(dev);
1389 if (vhost_iotlb_add_range(dev->iotlb, msg->iova,
1390 msg->iova + msg->size - 1,
1391 msg->uaddr, msg->perm)) {
1392 ret = -ENOMEM;
1393 break;
1394 }
1395 vhost_iotlb_notify_vq(dev, msg);
1396 break;
1397 case VHOST_IOTLB_INVALIDATE:
1398 if (!dev->iotlb) {
1399 ret = -EFAULT;
1400 break;
1401 }
1402 vhost_vq_meta_reset(dev);
1403 vhost_iotlb_del_range(dev->iotlb, msg->iova,
1404 msg->iova + msg->size - 1);
1405 break;
1406 default:
1407 ret = -EINVAL;
1408 break;
1409 }
1410
1411 vhost_dev_unlock_vqs(dev);
1412 mutex_unlock(&dev->mutex);
1413
1414 return ret;
1415}
1416ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
1417 struct iov_iter *from)
1418{
1419 struct vhost_iotlb_msg msg;
1420 size_t offset;
1421 int type, ret;
1422 u32 asid = 0;
1423
1424 ret = copy_from_iter(&type, sizeof(type), from);
1425 if (ret != sizeof(type)) {
1426 ret = -EINVAL;
1427 goto done;
1428 }
1429
1430 switch (type) {
1431 case VHOST_IOTLB_MSG:
1432 /* There maybe a hole after type for V1 message type,
1433 * so skip it here.
1434 */
1435 offset = offsetof(struct vhost_msg, iotlb) - sizeof(int);
1436 break;
1437 case VHOST_IOTLB_MSG_V2:
1438 if (vhost_backend_has_feature(dev->vqs[0],
1439 VHOST_BACKEND_F_IOTLB_ASID)) {
1440 ret = copy_from_iter(&asid, sizeof(asid), from);
1441 if (ret != sizeof(asid)) {
1442 ret = -EINVAL;
1443 goto done;
1444 }
1445 offset = 0;
1446 } else
1447 offset = sizeof(__u32);
1448 break;
1449 default:
1450 ret = -EINVAL;
1451 goto done;
1452 }
1453
1454 iov_iter_advance(from, offset);
1455 ret = copy_from_iter(&msg, sizeof(msg), from);
1456 if (ret != sizeof(msg)) {
1457 ret = -EINVAL;
1458 goto done;
1459 }
1460
1461 if (msg.type == VHOST_IOTLB_UPDATE && msg.size == 0) {
1462 ret = -EINVAL;
1463 goto done;
1464 }
1465
1466 if (dev->msg_handler)
1467 ret = dev->msg_handler(dev, asid, &msg);
1468 else
1469 ret = vhost_process_iotlb_msg(dev, asid, &msg);
1470 if (ret) {
1471 ret = -EFAULT;
1472 goto done;
1473 }
1474
1475 ret = (type == VHOST_IOTLB_MSG) ? sizeof(struct vhost_msg) :
1476 sizeof(struct vhost_msg_v2);
1477done:
1478 return ret;
1479}
1480EXPORT_SYMBOL(vhost_chr_write_iter);
1481
1482__poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
1483 poll_table *wait)
1484{
1485 __poll_t mask = 0;
1486
1487 poll_wait(file, &dev->wait, wait);
1488
1489 if (!list_empty(&dev->read_list))
1490 mask |= EPOLLIN | EPOLLRDNORM;
1491
1492 return mask;
1493}
1494EXPORT_SYMBOL(vhost_chr_poll);
1495
1496ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
1497 int noblock)
1498{
1499 DEFINE_WAIT(wait);
1500 struct vhost_msg_node *node;
1501 ssize_t ret = 0;
1502 unsigned size = sizeof(struct vhost_msg);
1503
1504 if (iov_iter_count(to) < size)
1505 return 0;
1506
1507 while (1) {
1508 if (!noblock)
1509 prepare_to_wait(&dev->wait, &wait,
1510 TASK_INTERRUPTIBLE);
1511
1512 node = vhost_dequeue_msg(dev, &dev->read_list);
1513 if (node)
1514 break;
1515 if (noblock) {
1516 ret = -EAGAIN;
1517 break;
1518 }
1519 if (signal_pending(current)) {
1520 ret = -ERESTARTSYS;
1521 break;
1522 }
1523 if (!dev->iotlb) {
1524 ret = -EBADFD;
1525 break;
1526 }
1527
1528 schedule();
1529 }
1530
1531 if (!noblock)
1532 finish_wait(&dev->wait, &wait);
1533
1534 if (node) {
1535 struct vhost_iotlb_msg *msg;
1536 void *start = &node->msg;
1537
1538 switch (node->msg.type) {
1539 case VHOST_IOTLB_MSG:
1540 size = sizeof(node->msg);
1541 msg = &node->msg.iotlb;
1542 break;
1543 case VHOST_IOTLB_MSG_V2:
1544 size = sizeof(node->msg_v2);
1545 msg = &node->msg_v2.iotlb;
1546 break;
1547 default:
1548 BUG();
1549 break;
1550 }
1551
1552 ret = copy_to_iter(start, size, to);
1553 if (ret != size || msg->type != VHOST_IOTLB_MISS) {
1554 kfree(node);
1555 return ret;
1556 }
1557 vhost_enqueue_msg(dev, &dev->pending_list, node);
1558 }
1559
1560 return ret;
1561}
1562EXPORT_SYMBOL_GPL(vhost_chr_read_iter);
1563
1564static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access)
1565{
1566 struct vhost_dev *dev = vq->dev;
1567 struct vhost_msg_node *node;
1568 struct vhost_iotlb_msg *msg;
1569 bool v2 = vhost_backend_has_feature(vq, VHOST_BACKEND_F_IOTLB_MSG_V2);
1570
1571 node = vhost_new_msg(vq, v2 ? VHOST_IOTLB_MSG_V2 : VHOST_IOTLB_MSG);
1572 if (!node)
1573 return -ENOMEM;
1574
1575 if (v2) {
1576 node->msg_v2.type = VHOST_IOTLB_MSG_V2;
1577 msg = &node->msg_v2.iotlb;
1578 } else {
1579 msg = &node->msg.iotlb;
1580 }
1581
1582 msg->type = VHOST_IOTLB_MISS;
1583 msg->iova = iova;
1584 msg->perm = access;
1585
1586 vhost_enqueue_msg(dev, &dev->read_list, node);
1587
1588 return 0;
1589}
1590
1591static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
1592 vring_desc_t __user *desc,
1593 vring_avail_t __user *avail,
1594 vring_used_t __user *used)
1595
1596{
1597 /* If an IOTLB device is present, the vring addresses are
1598 * GIOVAs. Access validation occurs at prefetch time. */
1599 if (vq->iotlb)
1600 return true;
1601
1602 return access_ok(desc, vhost_get_desc_size(vq, num)) &&
1603 access_ok(avail, vhost_get_avail_size(vq, num)) &&
1604 access_ok(used, vhost_get_used_size(vq, num));
1605}
1606
1607static void vhost_vq_meta_update(struct vhost_virtqueue *vq,
1608 const struct vhost_iotlb_map *map,
1609 int type)
1610{
1611 int access = (type == VHOST_ADDR_USED) ?
1612 VHOST_ACCESS_WO : VHOST_ACCESS_RO;
1613
1614 if (likely(map->perm & access))
1615 vq->meta_iotlb[type] = map;
1616}
1617
1618static bool iotlb_access_ok(struct vhost_virtqueue *vq,
1619 int access, u64 addr, u64 len, int type)
1620{
1621 const struct vhost_iotlb_map *map;
1622 struct vhost_iotlb *umem = vq->iotlb;
1623 u64 s = 0, size, orig_addr = addr, last = addr + len - 1;
1624
1625 if (vhost_vq_meta_fetch(vq, addr, len, type))
1626 return true;
1627
1628 while (len > s) {
1629 map = vhost_iotlb_itree_first(umem, addr, last);
1630 if (map == NULL || map->start > addr) {
1631 vhost_iotlb_miss(vq, addr, access);
1632 return false;
1633 } else if (!(map->perm & access)) {
1634 /* Report the possible access violation by
1635 * request another translation from userspace.
1636 */
1637 return false;
1638 }
1639
1640 size = map->size - addr + map->start;
1641
1642 if (orig_addr == addr && size >= len)
1643 vhost_vq_meta_update(vq, map, type);
1644
1645 s += size;
1646 addr += size;
1647 }
1648
1649 return true;
1650}
1651
1652int vq_meta_prefetch(struct vhost_virtqueue *vq)
1653{
1654 unsigned int num = vq->num;
1655
1656 if (!vq->iotlb)
1657 return 1;
1658
1659 return iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->desc,
1660 vhost_get_desc_size(vq, num), VHOST_ADDR_DESC) &&
1661 iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->avail,
1662 vhost_get_avail_size(vq, num),
1663 VHOST_ADDR_AVAIL) &&
1664 iotlb_access_ok(vq, VHOST_MAP_WO, (u64)(uintptr_t)vq->used,
1665 vhost_get_used_size(vq, num), VHOST_ADDR_USED);
1666}
1667EXPORT_SYMBOL_GPL(vq_meta_prefetch);
1668
1669/* Can we log writes? */
1670/* Caller should have device mutex but not vq mutex */
1671bool vhost_log_access_ok(struct vhost_dev *dev)
1672{
1673 return memory_access_ok(dev, dev->umem, 1);
1674}
1675EXPORT_SYMBOL_GPL(vhost_log_access_ok);
1676
1677static bool vq_log_used_access_ok(struct vhost_virtqueue *vq,
1678 void __user *log_base,
1679 bool log_used,
1680 u64 log_addr)
1681{
1682 /* If an IOTLB device is present, log_addr is a GIOVA that
1683 * will never be logged by log_used(). */
1684 if (vq->iotlb)
1685 return true;
1686
1687 return !log_used || log_access_ok(log_base, log_addr,
1688 vhost_get_used_size(vq, vq->num));
1689}
1690
1691/* Verify access for write logging. */
1692/* Caller should have vq mutex and device mutex */
1693static bool vq_log_access_ok(struct vhost_virtqueue *vq,
1694 void __user *log_base)
1695{
1696 return vq_memory_access_ok(log_base, vq->umem,
1697 vhost_has_feature(vq, VHOST_F_LOG_ALL)) &&
1698 vq_log_used_access_ok(vq, log_base, vq->log_used, vq->log_addr);
1699}
1700
1701/* Can we start vq? */
1702/* Caller should have vq mutex and device mutex */
1703bool vhost_vq_access_ok(struct vhost_virtqueue *vq)
1704{
1705 if (!vq_log_access_ok(vq, vq->log_base))
1706 return false;
1707
1708 return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used);
1709}
1710EXPORT_SYMBOL_GPL(vhost_vq_access_ok);
1711
1712static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
1713{
1714 struct vhost_memory mem, *newmem;
1715 struct vhost_memory_region *region;
1716 struct vhost_iotlb *newumem, *oldumem;
1717 unsigned long size = offsetof(struct vhost_memory, regions);
1718 int i;
1719
1720 if (copy_from_user(&mem, m, size))
1721 return -EFAULT;
1722 if (mem.padding)
1723 return -EOPNOTSUPP;
1724 if (mem.nregions > max_mem_regions)
1725 return -E2BIG;
1726 newmem = kvzalloc(struct_size(newmem, regions, mem.nregions),
1727 GFP_KERNEL);
1728 if (!newmem)
1729 return -ENOMEM;
1730
1731 memcpy(newmem, &mem, size);
1732 if (copy_from_user(newmem->regions, m->regions,
1733 flex_array_size(newmem, regions, mem.nregions))) {
1734 kvfree(newmem);
1735 return -EFAULT;
1736 }
1737
1738 newumem = iotlb_alloc();
1739 if (!newumem) {
1740 kvfree(newmem);
1741 return -ENOMEM;
1742 }
1743
1744 for (region = newmem->regions;
1745 region < newmem->regions + mem.nregions;
1746 region++) {
1747 if (vhost_iotlb_add_range(newumem,
1748 region->guest_phys_addr,
1749 region->guest_phys_addr +
1750 region->memory_size - 1,
1751 region->userspace_addr,
1752 VHOST_MAP_RW))
1753 goto err;
1754 }
1755
1756 if (!memory_access_ok(d, newumem, 0))
1757 goto err;
1758
1759 oldumem = d->umem;
1760 d->umem = newumem;
1761
1762 /* All memory accesses are done under some VQ mutex. */
1763 for (i = 0; i < d->nvqs; ++i) {
1764 mutex_lock(&d->vqs[i]->mutex);
1765 d->vqs[i]->umem = newumem;
1766 mutex_unlock(&d->vqs[i]->mutex);
1767 }
1768
1769 kvfree(newmem);
1770 vhost_iotlb_free(oldumem);
1771 return 0;
1772
1773err:
1774 vhost_iotlb_free(newumem);
1775 kvfree(newmem);
1776 return -EFAULT;
1777}
1778
1779static long vhost_vring_set_num(struct vhost_dev *d,
1780 struct vhost_virtqueue *vq,
1781 void __user *argp)
1782{
1783 struct vhost_vring_state s;
1784
1785 /* Resizing ring with an active backend?
1786 * You don't want to do that. */
1787 if (vq->private_data)
1788 return -EBUSY;
1789
1790 if (copy_from_user(&s, argp, sizeof s))
1791 return -EFAULT;
1792
1793 if (!s.num || s.num > 0xffff || (s.num & (s.num - 1)))
1794 return -EINVAL;
1795 vq->num = s.num;
1796
1797 return 0;
1798}
1799
1800static long vhost_vring_set_addr(struct vhost_dev *d,
1801 struct vhost_virtqueue *vq,
1802 void __user *argp)
1803{
1804 struct vhost_vring_addr a;
1805
1806 if (copy_from_user(&a, argp, sizeof a))
1807 return -EFAULT;
1808 if (a.flags & ~(0x1 << VHOST_VRING_F_LOG))
1809 return -EOPNOTSUPP;
1810
1811 /* For 32bit, verify that the top 32bits of the user
1812 data are set to zero. */
1813 if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr ||
1814 (u64)(unsigned long)a.used_user_addr != a.used_user_addr ||
1815 (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr)
1816 return -EFAULT;
1817
1818 /* Make sure it's safe to cast pointers to vring types. */
1819 BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE);
1820 BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE);
1821 if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) ||
1822 (a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) ||
1823 (a.log_guest_addr & (VRING_USED_ALIGN_SIZE - 1)))
1824 return -EINVAL;
1825
1826 /* We only verify access here if backend is configured.
1827 * If it is not, we don't as size might not have been setup.
1828 * We will verify when backend is configured. */
1829 if (vq->private_data) {
1830 if (!vq_access_ok(vq, vq->num,
1831 (void __user *)(unsigned long)a.desc_user_addr,
1832 (void __user *)(unsigned long)a.avail_user_addr,
1833 (void __user *)(unsigned long)a.used_user_addr))
1834 return -EINVAL;
1835
1836 /* Also validate log access for used ring if enabled. */
1837 if (!vq_log_used_access_ok(vq, vq->log_base,
1838 a.flags & (0x1 << VHOST_VRING_F_LOG),
1839 a.log_guest_addr))
1840 return -EINVAL;
1841 }
1842
1843 vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG));
1844 vq->desc = (void __user *)(unsigned long)a.desc_user_addr;
1845 vq->avail = (void __user *)(unsigned long)a.avail_user_addr;
1846 vq->log_addr = a.log_guest_addr;
1847 vq->used = (void __user *)(unsigned long)a.used_user_addr;
1848
1849 return 0;
1850}
1851
1852static long vhost_vring_set_num_addr(struct vhost_dev *d,
1853 struct vhost_virtqueue *vq,
1854 unsigned int ioctl,
1855 void __user *argp)
1856{
1857 long r;
1858
1859 mutex_lock(&vq->mutex);
1860
1861 switch (ioctl) {
1862 case VHOST_SET_VRING_NUM:
1863 r = vhost_vring_set_num(d, vq, argp);
1864 break;
1865 case VHOST_SET_VRING_ADDR:
1866 r = vhost_vring_set_addr(d, vq, argp);
1867 break;
1868 default:
1869 BUG();
1870 }
1871
1872 mutex_unlock(&vq->mutex);
1873
1874 return r;
1875}
1876long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
1877{
1878 struct file *eventfp, *filep = NULL;
1879 bool pollstart = false, pollstop = false;
1880 struct eventfd_ctx *ctx = NULL;
1881 struct vhost_virtqueue *vq;
1882 struct vhost_vring_state s;
1883 struct vhost_vring_file f;
1884 u32 idx;
1885 long r;
1886
1887 r = vhost_get_vq_from_user(d, argp, &vq, &idx);
1888 if (r < 0)
1889 return r;
1890
1891 if (ioctl == VHOST_SET_VRING_NUM ||
1892 ioctl == VHOST_SET_VRING_ADDR) {
1893 return vhost_vring_set_num_addr(d, vq, ioctl, argp);
1894 }
1895
1896 mutex_lock(&vq->mutex);
1897
1898 switch (ioctl) {
1899 case VHOST_SET_VRING_BASE:
1900 /* Moving base with an active backend?
1901 * You don't want to do that. */
1902 if (vq->private_data) {
1903 r = -EBUSY;
1904 break;
1905 }
1906 if (copy_from_user(&s, argp, sizeof s)) {
1907 r = -EFAULT;
1908 break;
1909 }
1910 if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) {
1911 vq->last_avail_idx = s.num & 0xffff;
1912 vq->last_used_idx = (s.num >> 16) & 0xffff;
1913 } else {
1914 if (s.num > 0xffff) {
1915 r = -EINVAL;
1916 break;
1917 }
1918 vq->last_avail_idx = s.num;
1919 }
1920 /* Forget the cached index value. */
1921 vq->avail_idx = vq->last_avail_idx;
1922 break;
1923 case VHOST_GET_VRING_BASE:
1924 s.index = idx;
1925 if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
1926 s.num = (u32)vq->last_avail_idx | ((u32)vq->last_used_idx << 16);
1927 else
1928 s.num = vq->last_avail_idx;
1929 if (copy_to_user(argp, &s, sizeof s))
1930 r = -EFAULT;
1931 break;
1932 case VHOST_SET_VRING_KICK:
1933 if (copy_from_user(&f, argp, sizeof f)) {
1934 r = -EFAULT;
1935 break;
1936 }
1937 eventfp = f.fd == VHOST_FILE_UNBIND ? NULL : eventfd_fget(f.fd);
1938 if (IS_ERR(eventfp)) {
1939 r = PTR_ERR(eventfp);
1940 break;
1941 }
1942 if (eventfp != vq->kick) {
1943 pollstop = (filep = vq->kick) != NULL;
1944 pollstart = (vq->kick = eventfp) != NULL;
1945 } else
1946 filep = eventfp;
1947 break;
1948 case VHOST_SET_VRING_CALL:
1949 if (copy_from_user(&f, argp, sizeof f)) {
1950 r = -EFAULT;
1951 break;
1952 }
1953 ctx = f.fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(f.fd);
1954 if (IS_ERR(ctx)) {
1955 r = PTR_ERR(ctx);
1956 break;
1957 }
1958
1959 swap(ctx, vq->call_ctx.ctx);
1960 break;
1961 case VHOST_SET_VRING_ERR:
1962 if (copy_from_user(&f, argp, sizeof f)) {
1963 r = -EFAULT;
1964 break;
1965 }
1966 ctx = f.fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(f.fd);
1967 if (IS_ERR(ctx)) {
1968 r = PTR_ERR(ctx);
1969 break;
1970 }
1971 swap(ctx, vq->error_ctx);
1972 break;
1973 case VHOST_SET_VRING_ENDIAN:
1974 r = vhost_set_vring_endian(vq, argp);
1975 break;
1976 case VHOST_GET_VRING_ENDIAN:
1977 r = vhost_get_vring_endian(vq, idx, argp);
1978 break;
1979 case VHOST_SET_VRING_BUSYLOOP_TIMEOUT:
1980 if (copy_from_user(&s, argp, sizeof(s))) {
1981 r = -EFAULT;
1982 break;
1983 }
1984 vq->busyloop_timeout = s.num;
1985 break;
1986 case VHOST_GET_VRING_BUSYLOOP_TIMEOUT:
1987 s.index = idx;
1988 s.num = vq->busyloop_timeout;
1989 if (copy_to_user(argp, &s, sizeof(s)))
1990 r = -EFAULT;
1991 break;
1992 default:
1993 r = -ENOIOCTLCMD;
1994 }
1995
1996 if (pollstop && vq->handle_kick)
1997 vhost_poll_stop(&vq->poll);
1998
1999 if (!IS_ERR_OR_NULL(ctx))
2000 eventfd_ctx_put(ctx);
2001 if (filep)
2002 fput(filep);
2003
2004 if (pollstart && vq->handle_kick)
2005 r = vhost_poll_start(&vq->poll, vq->kick);
2006
2007 mutex_unlock(&vq->mutex);
2008
2009 if (pollstop && vq->handle_kick)
2010 vhost_dev_flush(vq->poll.dev);
2011 return r;
2012}
2013EXPORT_SYMBOL_GPL(vhost_vring_ioctl);
2014
2015int vhost_init_device_iotlb(struct vhost_dev *d)
2016{
2017 struct vhost_iotlb *niotlb, *oiotlb;
2018 int i;
2019
2020 niotlb = iotlb_alloc();
2021 if (!niotlb)
2022 return -ENOMEM;
2023
2024 oiotlb = d->iotlb;
2025 d->iotlb = niotlb;
2026
2027 for (i = 0; i < d->nvqs; ++i) {
2028 struct vhost_virtqueue *vq = d->vqs[i];
2029
2030 mutex_lock(&vq->mutex);
2031 vq->iotlb = niotlb;
2032 __vhost_vq_meta_reset(vq);
2033 mutex_unlock(&vq->mutex);
2034 }
2035
2036 vhost_iotlb_free(oiotlb);
2037
2038 return 0;
2039}
2040EXPORT_SYMBOL_GPL(vhost_init_device_iotlb);
2041
2042/* Caller must have device mutex */
2043long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
2044{
2045 struct eventfd_ctx *ctx;
2046 u64 p;
2047 long r;
2048 int i, fd;
2049
2050 /* If you are not the owner, you can become one */
2051 if (ioctl == VHOST_SET_OWNER) {
2052 r = vhost_dev_set_owner(d);
2053 goto done;
2054 }
2055
2056 /* You must be the owner to do anything else */
2057 r = vhost_dev_check_owner(d);
2058 if (r)
2059 goto done;
2060
2061 switch (ioctl) {
2062 case VHOST_SET_MEM_TABLE:
2063 r = vhost_set_memory(d, argp);
2064 break;
2065 case VHOST_SET_LOG_BASE:
2066 if (copy_from_user(&p, argp, sizeof p)) {
2067 r = -EFAULT;
2068 break;
2069 }
2070 if ((u64)(unsigned long)p != p) {
2071 r = -EFAULT;
2072 break;
2073 }
2074 for (i = 0; i < d->nvqs; ++i) {
2075 struct vhost_virtqueue *vq;
2076 void __user *base = (void __user *)(unsigned long)p;
2077 vq = d->vqs[i];
2078 mutex_lock(&vq->mutex);
2079 /* If ring is inactive, will check when it's enabled. */
2080 if (vq->private_data && !vq_log_access_ok(vq, base))
2081 r = -EFAULT;
2082 else
2083 vq->log_base = base;
2084 mutex_unlock(&vq->mutex);
2085 }
2086 break;
2087 case VHOST_SET_LOG_FD:
2088 r = get_user(fd, (int __user *)argp);
2089 if (r < 0)
2090 break;
2091 ctx = fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(fd);
2092 if (IS_ERR(ctx)) {
2093 r = PTR_ERR(ctx);
2094 break;
2095 }
2096 swap(ctx, d->log_ctx);
2097 for (i = 0; i < d->nvqs; ++i) {
2098 mutex_lock(&d->vqs[i]->mutex);
2099 d->vqs[i]->log_ctx = d->log_ctx;
2100 mutex_unlock(&d->vqs[i]->mutex);
2101 }
2102 if (ctx)
2103 eventfd_ctx_put(ctx);
2104 break;
2105 default:
2106 r = -ENOIOCTLCMD;
2107 break;
2108 }
2109done:
2110 return r;
2111}
2112EXPORT_SYMBOL_GPL(vhost_dev_ioctl);
2113
2114/* TODO: This is really inefficient. We need something like get_user()
2115 * (instruction directly accesses the data, with an exception table entry
2116 * returning -EFAULT). See Documentation/arch/x86/exception-tables.rst.
2117 */
2118static int set_bit_to_user(int nr, void __user *addr)
2119{
2120 unsigned long log = (unsigned long)addr;
2121 struct page *page;
2122 void *base;
2123 int bit = nr + (log % PAGE_SIZE) * 8;
2124 int r;
2125
2126 r = pin_user_pages_fast(log, 1, FOLL_WRITE, &page);
2127 if (r < 0)
2128 return r;
2129 BUG_ON(r != 1);
2130 base = kmap_atomic(page);
2131 set_bit(bit, base);
2132 kunmap_atomic(base);
2133 unpin_user_pages_dirty_lock(&page, 1, true);
2134 return 0;
2135}
2136
2137static int log_write(void __user *log_base,
2138 u64 write_address, u64 write_length)
2139{
2140 u64 write_page = write_address / VHOST_PAGE_SIZE;
2141 int r;
2142
2143 if (!write_length)
2144 return 0;
2145 write_length += write_address % VHOST_PAGE_SIZE;
2146 for (;;) {
2147 u64 base = (u64)(unsigned long)log_base;
2148 u64 log = base + write_page / 8;
2149 int bit = write_page % 8;
2150 if ((u64)(unsigned long)log != log)
2151 return -EFAULT;
2152 r = set_bit_to_user(bit, (void __user *)(unsigned long)log);
2153 if (r < 0)
2154 return r;
2155 if (write_length <= VHOST_PAGE_SIZE)
2156 break;
2157 write_length -= VHOST_PAGE_SIZE;
2158 write_page += 1;
2159 }
2160 return r;
2161}
2162
2163static int log_write_hva(struct vhost_virtqueue *vq, u64 hva, u64 len)
2164{
2165 struct vhost_iotlb *umem = vq->umem;
2166 struct vhost_iotlb_map *u;
2167 u64 start, end, l, min;
2168 int r;
2169 bool hit = false;
2170
2171 while (len) {
2172 min = len;
2173 /* More than one GPAs can be mapped into a single HVA. So
2174 * iterate all possible umems here to be safe.
2175 */
2176 list_for_each_entry(u, &umem->list, link) {
2177 if (u->addr > hva - 1 + len ||
2178 u->addr - 1 + u->size < hva)
2179 continue;
2180 start = max(u->addr, hva);
2181 end = min(u->addr - 1 + u->size, hva - 1 + len);
2182 l = end - start + 1;
2183 r = log_write(vq->log_base,
2184 u->start + start - u->addr,
2185 l);
2186 if (r < 0)
2187 return r;
2188 hit = true;
2189 min = min(l, min);
2190 }
2191
2192 if (!hit)
2193 return -EFAULT;
2194
2195 len -= min;
2196 hva += min;
2197 }
2198
2199 return 0;
2200}
2201
2202static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len)
2203{
2204 struct iovec *iov = vq->log_iov;
2205 int i, ret;
2206
2207 if (!vq->iotlb)
2208 return log_write(vq->log_base, vq->log_addr + used_offset, len);
2209
2210 ret = translate_desc(vq, (uintptr_t)vq->used + used_offset,
2211 len, iov, 64, VHOST_ACCESS_WO);
2212 if (ret < 0)
2213 return ret;
2214
2215 for (i = 0; i < ret; i++) {
2216 ret = log_write_hva(vq, (uintptr_t)iov[i].iov_base,
2217 iov[i].iov_len);
2218 if (ret)
2219 return ret;
2220 }
2221
2222 return 0;
2223}
2224
2225int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
2226 unsigned int log_num, u64 len, struct iovec *iov, int count)
2227{
2228 int i, r;
2229
2230 /* Make sure data written is seen before log. */
2231 smp_wmb();
2232
2233 if (vq->iotlb) {
2234 for (i = 0; i < count; i++) {
2235 r = log_write_hva(vq, (uintptr_t)iov[i].iov_base,
2236 iov[i].iov_len);
2237 if (r < 0)
2238 return r;
2239 }
2240 return 0;
2241 }
2242
2243 for (i = 0; i < log_num; ++i) {
2244 u64 l = min(log[i].len, len);
2245 r = log_write(vq->log_base, log[i].addr, l);
2246 if (r < 0)
2247 return r;
2248 len -= l;
2249 if (!len) {
2250 if (vq->log_ctx)
2251 eventfd_signal(vq->log_ctx);
2252 return 0;
2253 }
2254 }
2255 /* Length written exceeds what we have stored. This is a bug. */
2256 BUG();
2257 return 0;
2258}
2259EXPORT_SYMBOL_GPL(vhost_log_write);
2260
2261static int vhost_update_used_flags(struct vhost_virtqueue *vq)
2262{
2263 void __user *used;
2264 if (vhost_put_used_flags(vq))
2265 return -EFAULT;
2266 if (unlikely(vq->log_used)) {
2267 /* Make sure the flag is seen before log. */
2268 smp_wmb();
2269 /* Log used flag write. */
2270 used = &vq->used->flags;
2271 log_used(vq, (used - (void __user *)vq->used),
2272 sizeof vq->used->flags);
2273 if (vq->log_ctx)
2274 eventfd_signal(vq->log_ctx);
2275 }
2276 return 0;
2277}
2278
2279static int vhost_update_avail_event(struct vhost_virtqueue *vq)
2280{
2281 if (vhost_put_avail_event(vq))
2282 return -EFAULT;
2283 if (unlikely(vq->log_used)) {
2284 void __user *used;
2285 /* Make sure the event is seen before log. */
2286 smp_wmb();
2287 /* Log avail event write */
2288 used = vhost_avail_event(vq);
2289 log_used(vq, (used - (void __user *)vq->used),
2290 sizeof *vhost_avail_event(vq));
2291 if (vq->log_ctx)
2292 eventfd_signal(vq->log_ctx);
2293 }
2294 return 0;
2295}
2296
2297int vhost_vq_init_access(struct vhost_virtqueue *vq)
2298{
2299 __virtio16 last_used_idx;
2300 int r;
2301 bool is_le = vq->is_le;
2302
2303 if (!vq->private_data)
2304 return 0;
2305
2306 vhost_init_is_le(vq);
2307
2308 r = vhost_update_used_flags(vq);
2309 if (r)
2310 goto err;
2311 vq->signalled_used_valid = false;
2312 if (!vq->iotlb &&
2313 !access_ok(&vq->used->idx, sizeof vq->used->idx)) {
2314 r = -EFAULT;
2315 goto err;
2316 }
2317 r = vhost_get_used_idx(vq, &last_used_idx);
2318 if (r) {
2319 vq_err(vq, "Can't access used idx at %p\n",
2320 &vq->used->idx);
2321 goto err;
2322 }
2323 vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx);
2324 return 0;
2325
2326err:
2327 vq->is_le = is_le;
2328 return r;
2329}
2330EXPORT_SYMBOL_GPL(vhost_vq_init_access);
2331
2332static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
2333 struct iovec iov[], int iov_size, int access)
2334{
2335 const struct vhost_iotlb_map *map;
2336 struct vhost_dev *dev = vq->dev;
2337 struct vhost_iotlb *umem = dev->iotlb ? dev->iotlb : dev->umem;
2338 struct iovec *_iov;
2339 u64 s = 0, last = addr + len - 1;
2340 int ret = 0;
2341
2342 while ((u64)len > s) {
2343 u64 size;
2344 if (unlikely(ret >= iov_size)) {
2345 ret = -ENOBUFS;
2346 break;
2347 }
2348
2349 map = vhost_iotlb_itree_first(umem, addr, last);
2350 if (map == NULL || map->start > addr) {
2351 if (umem != dev->iotlb) {
2352 ret = -EFAULT;
2353 break;
2354 }
2355 ret = -EAGAIN;
2356 break;
2357 } else if (!(map->perm & access)) {
2358 ret = -EPERM;
2359 break;
2360 }
2361
2362 _iov = iov + ret;
2363 size = map->size - addr + map->start;
2364 _iov->iov_len = min((u64)len - s, size);
2365 _iov->iov_base = (void __user *)(unsigned long)
2366 (map->addr + addr - map->start);
2367 s += size;
2368 addr += size;
2369 ++ret;
2370 }
2371
2372 if (ret == -EAGAIN)
2373 vhost_iotlb_miss(vq, addr, access);
2374 return ret;
2375}
2376
2377/* Each buffer in the virtqueues is actually a chain of descriptors. This
2378 * function returns the next descriptor in the chain,
2379 * or -1U if we're at the end. */
2380static unsigned next_desc(struct vhost_virtqueue *vq, struct vring_desc *desc)
2381{
2382 unsigned int next;
2383
2384 /* If this descriptor says it doesn't chain, we're done. */
2385 if (!(desc->flags & cpu_to_vhost16(vq, VRING_DESC_F_NEXT)))
2386 return -1U;
2387
2388 /* Check they're not leading us off end of descriptors. */
2389 next = vhost16_to_cpu(vq, READ_ONCE(desc->next));
2390 return next;
2391}
2392
2393static int get_indirect(struct vhost_virtqueue *vq,
2394 struct iovec iov[], unsigned int iov_size,
2395 unsigned int *out_num, unsigned int *in_num,
2396 struct vhost_log *log, unsigned int *log_num,
2397 struct vring_desc *indirect)
2398{
2399 struct vring_desc desc;
2400 unsigned int i = 0, count, found = 0;
2401 u32 len = vhost32_to_cpu(vq, indirect->len);
2402 struct iov_iter from;
2403 int ret, access;
2404
2405 /* Sanity check */
2406 if (unlikely(len % sizeof desc)) {
2407 vq_err(vq, "Invalid length in indirect descriptor: "
2408 "len 0x%llx not multiple of 0x%zx\n",
2409 (unsigned long long)len,
2410 sizeof desc);
2411 return -EINVAL;
2412 }
2413
2414 ret = translate_desc(vq, vhost64_to_cpu(vq, indirect->addr), len, vq->indirect,
2415 UIO_MAXIOV, VHOST_ACCESS_RO);
2416 if (unlikely(ret < 0)) {
2417 if (ret != -EAGAIN)
2418 vq_err(vq, "Translation failure %d in indirect.\n", ret);
2419 return ret;
2420 }
2421 iov_iter_init(&from, ITER_SOURCE, vq->indirect, ret, len);
2422 count = len / sizeof desc;
2423 /* Buffers are chained via a 16 bit next field, so
2424 * we can have at most 2^16 of these. */
2425 if (unlikely(count > USHRT_MAX + 1)) {
2426 vq_err(vq, "Indirect buffer length too big: %d\n",
2427 indirect->len);
2428 return -E2BIG;
2429 }
2430
2431 do {
2432 unsigned iov_count = *in_num + *out_num;
2433 if (unlikely(++found > count)) {
2434 vq_err(vq, "Loop detected: last one at %u "
2435 "indirect size %u\n",
2436 i, count);
2437 return -EINVAL;
2438 }
2439 if (unlikely(!copy_from_iter_full(&desc, sizeof(desc), &from))) {
2440 vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
2441 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
2442 return -EINVAL;
2443 }
2444 if (unlikely(desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT))) {
2445 vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n",
2446 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
2447 return -EINVAL;
2448 }
2449
2450 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
2451 access = VHOST_ACCESS_WO;
2452 else
2453 access = VHOST_ACCESS_RO;
2454
2455 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
2456 vhost32_to_cpu(vq, desc.len), iov + iov_count,
2457 iov_size - iov_count, access);
2458 if (unlikely(ret < 0)) {
2459 if (ret != -EAGAIN)
2460 vq_err(vq, "Translation failure %d indirect idx %d\n",
2461 ret, i);
2462 return ret;
2463 }
2464 /* If this is an input descriptor, increment that count. */
2465 if (access == VHOST_ACCESS_WO) {
2466 *in_num += ret;
2467 if (unlikely(log && ret)) {
2468 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
2469 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
2470 ++*log_num;
2471 }
2472 } else {
2473 /* If it's an output descriptor, they're all supposed
2474 * to come before any input descriptors. */
2475 if (unlikely(*in_num)) {
2476 vq_err(vq, "Indirect descriptor "
2477 "has out after in: idx %d\n", i);
2478 return -EINVAL;
2479 }
2480 *out_num += ret;
2481 }
2482 } while ((i = next_desc(vq, &desc)) != -1);
2483 return 0;
2484}
2485
2486/* This looks in the virtqueue and for the first available buffer, and converts
2487 * it to an iovec for convenient access. Since descriptors consist of some
2488 * number of output then some number of input descriptors, it's actually two
2489 * iovecs, but we pack them into one and note how many of each there were.
2490 *
2491 * This function returns the descriptor number found, or vq->num (which is
2492 * never a valid descriptor number) if none was found. A negative code is
2493 * returned on error. */
2494int vhost_get_vq_desc(struct vhost_virtqueue *vq,
2495 struct iovec iov[], unsigned int iov_size,
2496 unsigned int *out_num, unsigned int *in_num,
2497 struct vhost_log *log, unsigned int *log_num)
2498{
2499 struct vring_desc desc;
2500 unsigned int i, head, found = 0;
2501 u16 last_avail_idx;
2502 __virtio16 avail_idx;
2503 __virtio16 ring_head;
2504 int ret, access;
2505
2506 /* Check it isn't doing very strange things with descriptor numbers. */
2507 last_avail_idx = vq->last_avail_idx;
2508
2509 if (vq->avail_idx == vq->last_avail_idx) {
2510 if (unlikely(vhost_get_avail_idx(vq, &avail_idx))) {
2511 vq_err(vq, "Failed to access avail idx at %p\n",
2512 &vq->avail->idx);
2513 return -EFAULT;
2514 }
2515 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2516
2517 if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) {
2518 vq_err(vq, "Guest moved used index from %u to %u",
2519 last_avail_idx, vq->avail_idx);
2520 return -EFAULT;
2521 }
2522
2523 /* If there's nothing new since last we looked, return
2524 * invalid.
2525 */
2526 if (vq->avail_idx == last_avail_idx)
2527 return vq->num;
2528
2529 /* Only get avail ring entries after they have been
2530 * exposed by guest.
2531 */
2532 smp_rmb();
2533 }
2534
2535 /* Grab the next descriptor number they're advertising, and increment
2536 * the index we've seen. */
2537 if (unlikely(vhost_get_avail_head(vq, &ring_head, last_avail_idx))) {
2538 vq_err(vq, "Failed to read head: idx %d address %p\n",
2539 last_avail_idx,
2540 &vq->avail->ring[last_avail_idx % vq->num]);
2541 return -EFAULT;
2542 }
2543
2544 head = vhost16_to_cpu(vq, ring_head);
2545
2546 /* If their number is silly, that's an error. */
2547 if (unlikely(head >= vq->num)) {
2548 vq_err(vq, "Guest says index %u > %u is available",
2549 head, vq->num);
2550 return -EINVAL;
2551 }
2552
2553 /* When we start there are none of either input nor output. */
2554 *out_num = *in_num = 0;
2555 if (unlikely(log))
2556 *log_num = 0;
2557
2558 i = head;
2559 do {
2560 unsigned iov_count = *in_num + *out_num;
2561 if (unlikely(i >= vq->num)) {
2562 vq_err(vq, "Desc index is %u > %u, head = %u",
2563 i, vq->num, head);
2564 return -EINVAL;
2565 }
2566 if (unlikely(++found > vq->num)) {
2567 vq_err(vq, "Loop detected: last one at %u "
2568 "vq size %u head %u\n",
2569 i, vq->num, head);
2570 return -EINVAL;
2571 }
2572 ret = vhost_get_desc(vq, &desc, i);
2573 if (unlikely(ret)) {
2574 vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
2575 i, vq->desc + i);
2576 return -EFAULT;
2577 }
2578 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT)) {
2579 ret = get_indirect(vq, iov, iov_size,
2580 out_num, in_num,
2581 log, log_num, &desc);
2582 if (unlikely(ret < 0)) {
2583 if (ret != -EAGAIN)
2584 vq_err(vq, "Failure detected "
2585 "in indirect descriptor at idx %d\n", i);
2586 return ret;
2587 }
2588 continue;
2589 }
2590
2591 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
2592 access = VHOST_ACCESS_WO;
2593 else
2594 access = VHOST_ACCESS_RO;
2595 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
2596 vhost32_to_cpu(vq, desc.len), iov + iov_count,
2597 iov_size - iov_count, access);
2598 if (unlikely(ret < 0)) {
2599 if (ret != -EAGAIN)
2600 vq_err(vq, "Translation failure %d descriptor idx %d\n",
2601 ret, i);
2602 return ret;
2603 }
2604 if (access == VHOST_ACCESS_WO) {
2605 /* If this is an input descriptor,
2606 * increment that count. */
2607 *in_num += ret;
2608 if (unlikely(log && ret)) {
2609 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
2610 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
2611 ++*log_num;
2612 }
2613 } else {
2614 /* If it's an output descriptor, they're all supposed
2615 * to come before any input descriptors. */
2616 if (unlikely(*in_num)) {
2617 vq_err(vq, "Descriptor has out after in: "
2618 "idx %d\n", i);
2619 return -EINVAL;
2620 }
2621 *out_num += ret;
2622 }
2623 } while ((i = next_desc(vq, &desc)) != -1);
2624
2625 /* On success, increment avail index. */
2626 vq->last_avail_idx++;
2627
2628 /* Assume notifications from guest are disabled at this point,
2629 * if they aren't we would need to update avail_event index. */
2630 BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY));
2631 return head;
2632}
2633EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
2634
2635/* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
2636void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n)
2637{
2638 vq->last_avail_idx -= n;
2639}
2640EXPORT_SYMBOL_GPL(vhost_discard_vq_desc);
2641
2642/* After we've used one of their buffers, we tell them about it. We'll then
2643 * want to notify the guest, using eventfd. */
2644int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
2645{
2646 struct vring_used_elem heads = {
2647 cpu_to_vhost32(vq, head),
2648 cpu_to_vhost32(vq, len)
2649 };
2650
2651 return vhost_add_used_n(vq, &heads, 1);
2652}
2653EXPORT_SYMBOL_GPL(vhost_add_used);
2654
2655static int __vhost_add_used_n(struct vhost_virtqueue *vq,
2656 struct vring_used_elem *heads,
2657 unsigned count)
2658{
2659 vring_used_elem_t __user *used;
2660 u16 old, new;
2661 int start;
2662
2663 start = vq->last_used_idx & (vq->num - 1);
2664 used = vq->used->ring + start;
2665 if (vhost_put_used(vq, heads, start, count)) {
2666 vq_err(vq, "Failed to write used");
2667 return -EFAULT;
2668 }
2669 if (unlikely(vq->log_used)) {
2670 /* Make sure data is seen before log. */
2671 smp_wmb();
2672 /* Log used ring entry write. */
2673 log_used(vq, ((void __user *)used - (void __user *)vq->used),
2674 count * sizeof *used);
2675 }
2676 old = vq->last_used_idx;
2677 new = (vq->last_used_idx += count);
2678 /* If the driver never bothers to signal in a very long while,
2679 * used index might wrap around. If that happens, invalidate
2680 * signalled_used index we stored. TODO: make sure driver
2681 * signals at least once in 2^16 and remove this. */
2682 if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old)))
2683 vq->signalled_used_valid = false;
2684 return 0;
2685}
2686
2687/* After we've used one of their buffers, we tell them about it. We'll then
2688 * want to notify the guest, using eventfd. */
2689int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
2690 unsigned count)
2691{
2692 int start, n, r;
2693
2694 start = vq->last_used_idx & (vq->num - 1);
2695 n = vq->num - start;
2696 if (n < count) {
2697 r = __vhost_add_used_n(vq, heads, n);
2698 if (r < 0)
2699 return r;
2700 heads += n;
2701 count -= n;
2702 }
2703 r = __vhost_add_used_n(vq, heads, count);
2704
2705 /* Make sure buffer is written before we update index. */
2706 smp_wmb();
2707 if (vhost_put_used_idx(vq)) {
2708 vq_err(vq, "Failed to increment used idx");
2709 return -EFAULT;
2710 }
2711 if (unlikely(vq->log_used)) {
2712 /* Make sure used idx is seen before log. */
2713 smp_wmb();
2714 /* Log used index update. */
2715 log_used(vq, offsetof(struct vring_used, idx),
2716 sizeof vq->used->idx);
2717 if (vq->log_ctx)
2718 eventfd_signal(vq->log_ctx);
2719 }
2720 return r;
2721}
2722EXPORT_SYMBOL_GPL(vhost_add_used_n);
2723
2724static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2725{
2726 __u16 old, new;
2727 __virtio16 event;
2728 bool v;
2729 /* Flush out used index updates. This is paired
2730 * with the barrier that the Guest executes when enabling
2731 * interrupts. */
2732 smp_mb();
2733
2734 if (vhost_has_feature(vq, VIRTIO_F_NOTIFY_ON_EMPTY) &&
2735 unlikely(vq->avail_idx == vq->last_avail_idx))
2736 return true;
2737
2738 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2739 __virtio16 flags;
2740 if (vhost_get_avail_flags(vq, &flags)) {
2741 vq_err(vq, "Failed to get flags");
2742 return true;
2743 }
2744 return !(flags & cpu_to_vhost16(vq, VRING_AVAIL_F_NO_INTERRUPT));
2745 }
2746 old = vq->signalled_used;
2747 v = vq->signalled_used_valid;
2748 new = vq->signalled_used = vq->last_used_idx;
2749 vq->signalled_used_valid = true;
2750
2751 if (unlikely(!v))
2752 return true;
2753
2754 if (vhost_get_used_event(vq, &event)) {
2755 vq_err(vq, "Failed to get used event idx");
2756 return true;
2757 }
2758 return vring_need_event(vhost16_to_cpu(vq, event), new, old);
2759}
2760
2761/* This actually signals the guest, using eventfd. */
2762void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2763{
2764 /* Signal the Guest tell them we used something up. */
2765 if (vq->call_ctx.ctx && vhost_notify(dev, vq))
2766 eventfd_signal(vq->call_ctx.ctx);
2767}
2768EXPORT_SYMBOL_GPL(vhost_signal);
2769
2770/* And here's the combo meal deal. Supersize me! */
2771void vhost_add_used_and_signal(struct vhost_dev *dev,
2772 struct vhost_virtqueue *vq,
2773 unsigned int head, int len)
2774{
2775 vhost_add_used(vq, head, len);
2776 vhost_signal(dev, vq);
2777}
2778EXPORT_SYMBOL_GPL(vhost_add_used_and_signal);
2779
2780/* multi-buffer version of vhost_add_used_and_signal */
2781void vhost_add_used_and_signal_n(struct vhost_dev *dev,
2782 struct vhost_virtqueue *vq,
2783 struct vring_used_elem *heads, unsigned count)
2784{
2785 vhost_add_used_n(vq, heads, count);
2786 vhost_signal(dev, vq);
2787}
2788EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
2789
2790/* return true if we're sure that avaiable ring is empty */
2791bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2792{
2793 __virtio16 avail_idx;
2794 int r;
2795
2796 if (vq->avail_idx != vq->last_avail_idx)
2797 return false;
2798
2799 r = vhost_get_avail_idx(vq, &avail_idx);
2800 if (unlikely(r))
2801 return false;
2802 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2803
2804 return vq->avail_idx == vq->last_avail_idx;
2805}
2806EXPORT_SYMBOL_GPL(vhost_vq_avail_empty);
2807
2808/* OK, now we need to know about added descriptors. */
2809bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2810{
2811 __virtio16 avail_idx;
2812 int r;
2813
2814 if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
2815 return false;
2816 vq->used_flags &= ~VRING_USED_F_NO_NOTIFY;
2817 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2818 r = vhost_update_used_flags(vq);
2819 if (r) {
2820 vq_err(vq, "Failed to enable notification at %p: %d\n",
2821 &vq->used->flags, r);
2822 return false;
2823 }
2824 } else {
2825 r = vhost_update_avail_event(vq);
2826 if (r) {
2827 vq_err(vq, "Failed to update avail event index at %p: %d\n",
2828 vhost_avail_event(vq), r);
2829 return false;
2830 }
2831 }
2832 /* They could have slipped one in as we were doing that: make
2833 * sure it's written, then check again. */
2834 smp_mb();
2835 r = vhost_get_avail_idx(vq, &avail_idx);
2836 if (r) {
2837 vq_err(vq, "Failed to check avail idx at %p: %d\n",
2838 &vq->avail->idx, r);
2839 return false;
2840 }
2841 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2842
2843 return vq->avail_idx != vq->last_avail_idx;
2844}
2845EXPORT_SYMBOL_GPL(vhost_enable_notify);
2846
2847/* We don't need to be notified again. */
2848void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2849{
2850 int r;
2851
2852 if (vq->used_flags & VRING_USED_F_NO_NOTIFY)
2853 return;
2854 vq->used_flags |= VRING_USED_F_NO_NOTIFY;
2855 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2856 r = vhost_update_used_flags(vq);
2857 if (r)
2858 vq_err(vq, "Failed to disable notification at %p: %d\n",
2859 &vq->used->flags, r);
2860 }
2861}
2862EXPORT_SYMBOL_GPL(vhost_disable_notify);
2863
2864/* Create a new message. */
2865struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type)
2866{
2867 /* Make sure all padding within the structure is initialized. */
2868 struct vhost_msg_node *node = kzalloc(sizeof(*node), GFP_KERNEL);
2869 if (!node)
2870 return NULL;
2871
2872 node->vq = vq;
2873 node->msg.type = type;
2874 return node;
2875}
2876EXPORT_SYMBOL_GPL(vhost_new_msg);
2877
2878void vhost_enqueue_msg(struct vhost_dev *dev, struct list_head *head,
2879 struct vhost_msg_node *node)
2880{
2881 spin_lock(&dev->iotlb_lock);
2882 list_add_tail(&node->node, head);
2883 spin_unlock(&dev->iotlb_lock);
2884
2885 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
2886}
2887EXPORT_SYMBOL_GPL(vhost_enqueue_msg);
2888
2889struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
2890 struct list_head *head)
2891{
2892 struct vhost_msg_node *node = NULL;
2893
2894 spin_lock(&dev->iotlb_lock);
2895 if (!list_empty(head)) {
2896 node = list_first_entry(head, struct vhost_msg_node,
2897 node);
2898 list_del(&node->node);
2899 }
2900 spin_unlock(&dev->iotlb_lock);
2901
2902 return node;
2903}
2904EXPORT_SYMBOL_GPL(vhost_dequeue_msg);
2905
2906void vhost_set_backend_features(struct vhost_dev *dev, u64 features)
2907{
2908 struct vhost_virtqueue *vq;
2909 int i;
2910
2911 mutex_lock(&dev->mutex);
2912 for (i = 0; i < dev->nvqs; ++i) {
2913 vq = dev->vqs[i];
2914 mutex_lock(&vq->mutex);
2915 vq->acked_backend_features = features;
2916 mutex_unlock(&vq->mutex);
2917 }
2918 mutex_unlock(&dev->mutex);
2919}
2920EXPORT_SYMBOL_GPL(vhost_set_backend_features);
2921
2922static int __init vhost_init(void)
2923{
2924 return 0;
2925}
2926
2927static void __exit vhost_exit(void)
2928{
2929}
2930
2931module_init(vhost_init);
2932module_exit(vhost_exit);
2933
2934MODULE_VERSION("0.0.1");
2935MODULE_LICENSE("GPL v2");
2936MODULE_AUTHOR("Michael S. Tsirkin");
2937MODULE_DESCRIPTION("Host kernel accelerator for virtio");
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/miscdevice.h>
18#include <linux/mutex.h>
19#include <linux/poll.h>
20#include <linux/file.h>
21#include <linux/highmem.h>
22#include <linux/slab.h>
23#include <linux/vmalloc.h>
24#include <linux/kthread.h>
25#include <linux/module.h>
26#include <linux/sort.h>
27#include <linux/sched/mm.h>
28#include <linux/sched/signal.h>
29#include <linux/sched/vhost_task.h>
30#include <linux/interval_tree_generic.h>
31#include <linux/nospec.h>
32#include <linux/kcov.h>
33
34#include "vhost.h"
35
36static ushort max_mem_regions = 64;
37module_param(max_mem_regions, ushort, 0444);
38MODULE_PARM_DESC(max_mem_regions,
39 "Maximum number of memory regions in memory map. (default: 64)");
40static int max_iotlb_entries = 2048;
41module_param(max_iotlb_entries, int, 0444);
42MODULE_PARM_DESC(max_iotlb_entries,
43 "Maximum number of iotlb entries. (default: 2048)");
44
45enum {
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#ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
53static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
54{
55 vq->user_be = !virtio_legacy_is_little_endian();
56}
57
58static void vhost_enable_cross_endian_big(struct vhost_virtqueue *vq)
59{
60 vq->user_be = true;
61}
62
63static void vhost_enable_cross_endian_little(struct vhost_virtqueue *vq)
64{
65 vq->user_be = false;
66}
67
68static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
69{
70 struct vhost_vring_state s;
71
72 if (vq->private_data)
73 return -EBUSY;
74
75 if (copy_from_user(&s, argp, sizeof(s)))
76 return -EFAULT;
77
78 if (s.num != VHOST_VRING_LITTLE_ENDIAN &&
79 s.num != VHOST_VRING_BIG_ENDIAN)
80 return -EINVAL;
81
82 if (s.num == VHOST_VRING_BIG_ENDIAN)
83 vhost_enable_cross_endian_big(vq);
84 else
85 vhost_enable_cross_endian_little(vq);
86
87 return 0;
88}
89
90static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
91 int __user *argp)
92{
93 struct vhost_vring_state s = {
94 .index = idx,
95 .num = vq->user_be
96 };
97
98 if (copy_to_user(argp, &s, sizeof(s)))
99 return -EFAULT;
100
101 return 0;
102}
103
104static void vhost_init_is_le(struct vhost_virtqueue *vq)
105{
106 /* Note for legacy virtio: user_be is initialized at reset time
107 * according to the host endianness. If userspace does not set an
108 * explicit endianness, the default behavior is native endian, as
109 * expected by legacy virtio.
110 */
111 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1) || !vq->user_be;
112}
113#else
114static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
115{
116}
117
118static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
119{
120 return -ENOIOCTLCMD;
121}
122
123static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
124 int __user *argp)
125{
126 return -ENOIOCTLCMD;
127}
128
129static void vhost_init_is_le(struct vhost_virtqueue *vq)
130{
131 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1)
132 || virtio_legacy_is_little_endian();
133}
134#endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
135
136static void vhost_reset_is_le(struct vhost_virtqueue *vq)
137{
138 vhost_init_is_le(vq);
139}
140
141struct vhost_flush_struct {
142 struct vhost_work work;
143 struct completion wait_event;
144};
145
146static void vhost_flush_work(struct vhost_work *work)
147{
148 struct vhost_flush_struct *s;
149
150 s = container_of(work, struct vhost_flush_struct, work);
151 complete(&s->wait_event);
152}
153
154static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
155 poll_table *pt)
156{
157 struct vhost_poll *poll;
158
159 poll = container_of(pt, struct vhost_poll, table);
160 poll->wqh = wqh;
161 add_wait_queue(wqh, &poll->wait);
162}
163
164static int vhost_poll_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync,
165 void *key)
166{
167 struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait);
168 struct vhost_work *work = &poll->work;
169
170 if (!(key_to_poll(key) & poll->mask))
171 return 0;
172
173 if (!poll->dev->use_worker)
174 work->fn(work);
175 else
176 vhost_poll_queue(poll);
177
178 return 0;
179}
180
181void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn)
182{
183 clear_bit(VHOST_WORK_QUEUED, &work->flags);
184 work->fn = fn;
185}
186EXPORT_SYMBOL_GPL(vhost_work_init);
187
188/* Init poll structure */
189void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
190 __poll_t mask, struct vhost_dev *dev,
191 struct vhost_virtqueue *vq)
192{
193 init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup);
194 init_poll_funcptr(&poll->table, vhost_poll_func);
195 poll->mask = mask;
196 poll->dev = dev;
197 poll->wqh = NULL;
198 poll->vq = vq;
199
200 vhost_work_init(&poll->work, fn);
201}
202EXPORT_SYMBOL_GPL(vhost_poll_init);
203
204/* Start polling a file. We add ourselves to file's wait queue. The caller must
205 * keep a reference to a file until after vhost_poll_stop is called. */
206int vhost_poll_start(struct vhost_poll *poll, struct file *file)
207{
208 __poll_t mask;
209
210 if (poll->wqh)
211 return 0;
212
213 mask = vfs_poll(file, &poll->table);
214 if (mask)
215 vhost_poll_wakeup(&poll->wait, 0, 0, poll_to_key(mask));
216 if (mask & EPOLLERR) {
217 vhost_poll_stop(poll);
218 return -EINVAL;
219 }
220
221 return 0;
222}
223EXPORT_SYMBOL_GPL(vhost_poll_start);
224
225/* Stop polling a file. After this function returns, it becomes safe to drop the
226 * file reference. You must also flush afterwards. */
227void vhost_poll_stop(struct vhost_poll *poll)
228{
229 if (poll->wqh) {
230 remove_wait_queue(poll->wqh, &poll->wait);
231 poll->wqh = NULL;
232 }
233}
234EXPORT_SYMBOL_GPL(vhost_poll_stop);
235
236static void vhost_worker_queue(struct vhost_worker *worker,
237 struct vhost_work *work)
238{
239 if (!test_and_set_bit(VHOST_WORK_QUEUED, &work->flags)) {
240 /* We can only add the work to the list after we're
241 * sure it was not in the list.
242 * test_and_set_bit() implies a memory barrier.
243 */
244 llist_add(&work->node, &worker->work_list);
245 vhost_task_wake(worker->vtsk);
246 }
247}
248
249bool vhost_vq_work_queue(struct vhost_virtqueue *vq, struct vhost_work *work)
250{
251 struct vhost_worker *worker;
252 bool queued = false;
253
254 rcu_read_lock();
255 worker = rcu_dereference(vq->worker);
256 if (worker) {
257 queued = true;
258 vhost_worker_queue(worker, work);
259 }
260 rcu_read_unlock();
261
262 return queued;
263}
264EXPORT_SYMBOL_GPL(vhost_vq_work_queue);
265
266/**
267 * __vhost_worker_flush - flush a worker
268 * @worker: worker to flush
269 *
270 * The worker's flush_mutex must be held.
271 */
272static void __vhost_worker_flush(struct vhost_worker *worker)
273{
274 struct vhost_flush_struct flush;
275
276 if (!worker->attachment_cnt || worker->killed)
277 return;
278
279 init_completion(&flush.wait_event);
280 vhost_work_init(&flush.work, vhost_flush_work);
281
282 vhost_worker_queue(worker, &flush.work);
283 /*
284 * Drop mutex in case our worker is killed and it needs to take the
285 * mutex to force cleanup.
286 */
287 mutex_unlock(&worker->mutex);
288 wait_for_completion(&flush.wait_event);
289 mutex_lock(&worker->mutex);
290}
291
292static void vhost_worker_flush(struct vhost_worker *worker)
293{
294 mutex_lock(&worker->mutex);
295 __vhost_worker_flush(worker);
296 mutex_unlock(&worker->mutex);
297}
298
299void vhost_dev_flush(struct vhost_dev *dev)
300{
301 struct vhost_worker *worker;
302 unsigned long i;
303
304 xa_for_each(&dev->worker_xa, i, worker)
305 vhost_worker_flush(worker);
306}
307EXPORT_SYMBOL_GPL(vhost_dev_flush);
308
309/* A lockless hint for busy polling code to exit the loop */
310bool vhost_vq_has_work(struct vhost_virtqueue *vq)
311{
312 struct vhost_worker *worker;
313 bool has_work = false;
314
315 rcu_read_lock();
316 worker = rcu_dereference(vq->worker);
317 if (worker && !llist_empty(&worker->work_list))
318 has_work = true;
319 rcu_read_unlock();
320
321 return has_work;
322}
323EXPORT_SYMBOL_GPL(vhost_vq_has_work);
324
325void vhost_poll_queue(struct vhost_poll *poll)
326{
327 vhost_vq_work_queue(poll->vq, &poll->work);
328}
329EXPORT_SYMBOL_GPL(vhost_poll_queue);
330
331static void __vhost_vq_meta_reset(struct vhost_virtqueue *vq)
332{
333 int j;
334
335 for (j = 0; j < VHOST_NUM_ADDRS; j++)
336 vq->meta_iotlb[j] = NULL;
337}
338
339static void vhost_vq_meta_reset(struct vhost_dev *d)
340{
341 int i;
342
343 for (i = 0; i < d->nvqs; ++i)
344 __vhost_vq_meta_reset(d->vqs[i]);
345}
346
347static void vhost_vring_call_reset(struct vhost_vring_call *call_ctx)
348{
349 call_ctx->ctx = NULL;
350 memset(&call_ctx->producer, 0x0, sizeof(struct irq_bypass_producer));
351}
352
353bool vhost_vq_is_setup(struct vhost_virtqueue *vq)
354{
355 return vq->avail && vq->desc && vq->used && vhost_vq_access_ok(vq);
356}
357EXPORT_SYMBOL_GPL(vhost_vq_is_setup);
358
359static void vhost_vq_reset(struct vhost_dev *dev,
360 struct vhost_virtqueue *vq)
361{
362 vq->num = 1;
363 vq->desc = NULL;
364 vq->avail = NULL;
365 vq->used = NULL;
366 vq->last_avail_idx = 0;
367 vq->avail_idx = 0;
368 vq->last_used_idx = 0;
369 vq->signalled_used = 0;
370 vq->signalled_used_valid = false;
371 vq->used_flags = 0;
372 vq->log_used = false;
373 vq->log_addr = -1ull;
374 vq->private_data = NULL;
375 vq->acked_features = 0;
376 vq->acked_backend_features = 0;
377 vq->log_base = NULL;
378 vq->error_ctx = NULL;
379 vq->kick = NULL;
380 vq->log_ctx = NULL;
381 vhost_disable_cross_endian(vq);
382 vhost_reset_is_le(vq);
383 vq->busyloop_timeout = 0;
384 vq->umem = NULL;
385 vq->iotlb = NULL;
386 rcu_assign_pointer(vq->worker, NULL);
387 vhost_vring_call_reset(&vq->call_ctx);
388 __vhost_vq_meta_reset(vq);
389}
390
391static bool vhost_run_work_list(void *data)
392{
393 struct vhost_worker *worker = data;
394 struct vhost_work *work, *work_next;
395 struct llist_node *node;
396
397 node = llist_del_all(&worker->work_list);
398 if (node) {
399 __set_current_state(TASK_RUNNING);
400
401 node = llist_reverse_order(node);
402 /* make sure flag is seen after deletion */
403 smp_wmb();
404 llist_for_each_entry_safe(work, work_next, node, node) {
405 clear_bit(VHOST_WORK_QUEUED, &work->flags);
406 kcov_remote_start_common(worker->kcov_handle);
407 work->fn(work);
408 kcov_remote_stop();
409 cond_resched();
410 }
411 }
412
413 return !!node;
414}
415
416static void vhost_worker_killed(void *data)
417{
418 struct vhost_worker *worker = data;
419 struct vhost_dev *dev = worker->dev;
420 struct vhost_virtqueue *vq;
421 int i, attach_cnt = 0;
422
423 mutex_lock(&worker->mutex);
424 worker->killed = true;
425
426 for (i = 0; i < dev->nvqs; i++) {
427 vq = dev->vqs[i];
428
429 mutex_lock(&vq->mutex);
430 if (worker ==
431 rcu_dereference_check(vq->worker,
432 lockdep_is_held(&vq->mutex))) {
433 rcu_assign_pointer(vq->worker, NULL);
434 attach_cnt++;
435 }
436 mutex_unlock(&vq->mutex);
437 }
438
439 worker->attachment_cnt -= attach_cnt;
440 if (attach_cnt)
441 synchronize_rcu();
442 /*
443 * Finish vhost_worker_flush calls and any other works that snuck in
444 * before the synchronize_rcu.
445 */
446 vhost_run_work_list(worker);
447 mutex_unlock(&worker->mutex);
448}
449
450static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq)
451{
452 kfree(vq->indirect);
453 vq->indirect = NULL;
454 kfree(vq->log);
455 vq->log = NULL;
456 kfree(vq->heads);
457 vq->heads = NULL;
458}
459
460/* Helper to allocate iovec buffers for all vqs. */
461static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
462{
463 struct vhost_virtqueue *vq;
464 int i;
465
466 for (i = 0; i < dev->nvqs; ++i) {
467 vq = dev->vqs[i];
468 vq->indirect = kmalloc_array(UIO_MAXIOV,
469 sizeof(*vq->indirect),
470 GFP_KERNEL);
471 vq->log = kmalloc_array(dev->iov_limit, sizeof(*vq->log),
472 GFP_KERNEL);
473 vq->heads = kmalloc_array(dev->iov_limit, sizeof(*vq->heads),
474 GFP_KERNEL);
475 if (!vq->indirect || !vq->log || !vq->heads)
476 goto err_nomem;
477 }
478 return 0;
479
480err_nomem:
481 for (; i >= 0; --i)
482 vhost_vq_free_iovecs(dev->vqs[i]);
483 return -ENOMEM;
484}
485
486static void vhost_dev_free_iovecs(struct vhost_dev *dev)
487{
488 int i;
489
490 for (i = 0; i < dev->nvqs; ++i)
491 vhost_vq_free_iovecs(dev->vqs[i]);
492}
493
494bool vhost_exceeds_weight(struct vhost_virtqueue *vq,
495 int pkts, int total_len)
496{
497 struct vhost_dev *dev = vq->dev;
498
499 if ((dev->byte_weight && total_len >= dev->byte_weight) ||
500 pkts >= dev->weight) {
501 vhost_poll_queue(&vq->poll);
502 return true;
503 }
504
505 return false;
506}
507EXPORT_SYMBOL_GPL(vhost_exceeds_weight);
508
509static size_t vhost_get_avail_size(struct vhost_virtqueue *vq,
510 unsigned int num)
511{
512 size_t event __maybe_unused =
513 vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
514
515 return size_add(struct_size(vq->avail, ring, num), event);
516}
517
518static size_t vhost_get_used_size(struct vhost_virtqueue *vq,
519 unsigned int num)
520{
521 size_t event __maybe_unused =
522 vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
523
524 return size_add(struct_size(vq->used, ring, num), event);
525}
526
527static size_t vhost_get_desc_size(struct vhost_virtqueue *vq,
528 unsigned int num)
529{
530 return sizeof(*vq->desc) * num;
531}
532
533void vhost_dev_init(struct vhost_dev *dev,
534 struct vhost_virtqueue **vqs, int nvqs,
535 int iov_limit, int weight, int byte_weight,
536 bool use_worker,
537 int (*msg_handler)(struct vhost_dev *dev, u32 asid,
538 struct vhost_iotlb_msg *msg))
539{
540 struct vhost_virtqueue *vq;
541 int i;
542
543 dev->vqs = vqs;
544 dev->nvqs = nvqs;
545 mutex_init(&dev->mutex);
546 dev->log_ctx = NULL;
547 dev->umem = NULL;
548 dev->iotlb = NULL;
549 dev->mm = NULL;
550 dev->iov_limit = iov_limit;
551 dev->weight = weight;
552 dev->byte_weight = byte_weight;
553 dev->use_worker = use_worker;
554 dev->msg_handler = msg_handler;
555 init_waitqueue_head(&dev->wait);
556 INIT_LIST_HEAD(&dev->read_list);
557 INIT_LIST_HEAD(&dev->pending_list);
558 spin_lock_init(&dev->iotlb_lock);
559 xa_init_flags(&dev->worker_xa, XA_FLAGS_ALLOC);
560
561 for (i = 0; i < dev->nvqs; ++i) {
562 vq = dev->vqs[i];
563 vq->log = NULL;
564 vq->indirect = NULL;
565 vq->heads = NULL;
566 vq->dev = dev;
567 mutex_init(&vq->mutex);
568 vhost_vq_reset(dev, vq);
569 if (vq->handle_kick)
570 vhost_poll_init(&vq->poll, vq->handle_kick,
571 EPOLLIN, dev, vq);
572 }
573}
574EXPORT_SYMBOL_GPL(vhost_dev_init);
575
576/* Caller should have device mutex */
577long vhost_dev_check_owner(struct vhost_dev *dev)
578{
579 /* Are you the owner? If not, I don't think you mean to do that */
580 return dev->mm == current->mm ? 0 : -EPERM;
581}
582EXPORT_SYMBOL_GPL(vhost_dev_check_owner);
583
584/* Caller should have device mutex */
585bool vhost_dev_has_owner(struct vhost_dev *dev)
586{
587 return dev->mm;
588}
589EXPORT_SYMBOL_GPL(vhost_dev_has_owner);
590
591static void vhost_attach_mm(struct vhost_dev *dev)
592{
593 /* No owner, become one */
594 if (dev->use_worker) {
595 dev->mm = get_task_mm(current);
596 } else {
597 /* vDPA device does not use worker thead, so there's
598 * no need to hold the address space for mm. This help
599 * to avoid deadlock in the case of mmap() which may
600 * held the refcnt of the file and depends on release
601 * method to remove vma.
602 */
603 dev->mm = current->mm;
604 mmgrab(dev->mm);
605 }
606}
607
608static void vhost_detach_mm(struct vhost_dev *dev)
609{
610 if (!dev->mm)
611 return;
612
613 if (dev->use_worker)
614 mmput(dev->mm);
615 else
616 mmdrop(dev->mm);
617
618 dev->mm = NULL;
619}
620
621static void vhost_worker_destroy(struct vhost_dev *dev,
622 struct vhost_worker *worker)
623{
624 if (!worker)
625 return;
626
627 WARN_ON(!llist_empty(&worker->work_list));
628 xa_erase(&dev->worker_xa, worker->id);
629 vhost_task_stop(worker->vtsk);
630 kfree(worker);
631}
632
633static void vhost_workers_free(struct vhost_dev *dev)
634{
635 struct vhost_worker *worker;
636 unsigned long i;
637
638 if (!dev->use_worker)
639 return;
640
641 for (i = 0; i < dev->nvqs; i++)
642 rcu_assign_pointer(dev->vqs[i]->worker, NULL);
643 /*
644 * Free the default worker we created and cleanup workers userspace
645 * created but couldn't clean up (it forgot or crashed).
646 */
647 xa_for_each(&dev->worker_xa, i, worker)
648 vhost_worker_destroy(dev, worker);
649 xa_destroy(&dev->worker_xa);
650}
651
652static struct vhost_worker *vhost_worker_create(struct vhost_dev *dev)
653{
654 struct vhost_worker *worker;
655 struct vhost_task *vtsk;
656 char name[TASK_COMM_LEN];
657 int ret;
658 u32 id;
659
660 worker = kzalloc(sizeof(*worker), GFP_KERNEL_ACCOUNT);
661 if (!worker)
662 return NULL;
663
664 worker->dev = dev;
665 snprintf(name, sizeof(name), "vhost-%d", current->pid);
666
667 vtsk = vhost_task_create(vhost_run_work_list, vhost_worker_killed,
668 worker, name);
669 if (!vtsk)
670 goto free_worker;
671
672 mutex_init(&worker->mutex);
673 init_llist_head(&worker->work_list);
674 worker->kcov_handle = kcov_common_handle();
675 worker->vtsk = vtsk;
676
677 vhost_task_start(vtsk);
678
679 ret = xa_alloc(&dev->worker_xa, &id, worker, xa_limit_32b, GFP_KERNEL);
680 if (ret < 0)
681 goto stop_worker;
682 worker->id = id;
683
684 return worker;
685
686stop_worker:
687 vhost_task_stop(vtsk);
688free_worker:
689 kfree(worker);
690 return NULL;
691}
692
693/* Caller must have device mutex */
694static void __vhost_vq_attach_worker(struct vhost_virtqueue *vq,
695 struct vhost_worker *worker)
696{
697 struct vhost_worker *old_worker;
698
699 mutex_lock(&worker->mutex);
700 if (worker->killed) {
701 mutex_unlock(&worker->mutex);
702 return;
703 }
704
705 mutex_lock(&vq->mutex);
706
707 old_worker = rcu_dereference_check(vq->worker,
708 lockdep_is_held(&vq->mutex));
709 rcu_assign_pointer(vq->worker, worker);
710 worker->attachment_cnt++;
711
712 if (!old_worker) {
713 mutex_unlock(&vq->mutex);
714 mutex_unlock(&worker->mutex);
715 return;
716 }
717 mutex_unlock(&vq->mutex);
718 mutex_unlock(&worker->mutex);
719
720 /*
721 * Take the worker mutex to make sure we see the work queued from
722 * device wide flushes which doesn't use RCU for execution.
723 */
724 mutex_lock(&old_worker->mutex);
725 if (old_worker->killed) {
726 mutex_unlock(&old_worker->mutex);
727 return;
728 }
729
730 /*
731 * We don't want to call synchronize_rcu for every vq during setup
732 * because it will slow down VM startup. If we haven't done
733 * VHOST_SET_VRING_KICK and not done the driver specific
734 * SET_ENDPOINT/RUNNUNG then we can skip the sync since there will
735 * not be any works queued for scsi and net.
736 */
737 mutex_lock(&vq->mutex);
738 if (!vhost_vq_get_backend(vq) && !vq->kick) {
739 mutex_unlock(&vq->mutex);
740
741 old_worker->attachment_cnt--;
742 mutex_unlock(&old_worker->mutex);
743 /*
744 * vsock can queue anytime after VHOST_VSOCK_SET_GUEST_CID.
745 * Warn if it adds support for multiple workers but forgets to
746 * handle the early queueing case.
747 */
748 WARN_ON(!old_worker->attachment_cnt &&
749 !llist_empty(&old_worker->work_list));
750 return;
751 }
752 mutex_unlock(&vq->mutex);
753
754 /* Make sure new vq queue/flush/poll calls see the new worker */
755 synchronize_rcu();
756 /* Make sure whatever was queued gets run */
757 __vhost_worker_flush(old_worker);
758 old_worker->attachment_cnt--;
759 mutex_unlock(&old_worker->mutex);
760}
761
762 /* Caller must have device mutex */
763static int vhost_vq_attach_worker(struct vhost_virtqueue *vq,
764 struct vhost_vring_worker *info)
765{
766 unsigned long index = info->worker_id;
767 struct vhost_dev *dev = vq->dev;
768 struct vhost_worker *worker;
769
770 if (!dev->use_worker)
771 return -EINVAL;
772
773 worker = xa_find(&dev->worker_xa, &index, UINT_MAX, XA_PRESENT);
774 if (!worker || worker->id != info->worker_id)
775 return -ENODEV;
776
777 __vhost_vq_attach_worker(vq, worker);
778 return 0;
779}
780
781/* Caller must have device mutex */
782static int vhost_new_worker(struct vhost_dev *dev,
783 struct vhost_worker_state *info)
784{
785 struct vhost_worker *worker;
786
787 worker = vhost_worker_create(dev);
788 if (!worker)
789 return -ENOMEM;
790
791 info->worker_id = worker->id;
792 return 0;
793}
794
795/* Caller must have device mutex */
796static int vhost_free_worker(struct vhost_dev *dev,
797 struct vhost_worker_state *info)
798{
799 unsigned long index = info->worker_id;
800 struct vhost_worker *worker;
801
802 worker = xa_find(&dev->worker_xa, &index, UINT_MAX, XA_PRESENT);
803 if (!worker || worker->id != info->worker_id)
804 return -ENODEV;
805
806 mutex_lock(&worker->mutex);
807 if (worker->attachment_cnt || worker->killed) {
808 mutex_unlock(&worker->mutex);
809 return -EBUSY;
810 }
811 /*
812 * A flush might have raced and snuck in before attachment_cnt was set
813 * to zero. Make sure flushes are flushed from the queue before
814 * freeing.
815 */
816 __vhost_worker_flush(worker);
817 mutex_unlock(&worker->mutex);
818
819 vhost_worker_destroy(dev, worker);
820 return 0;
821}
822
823static int vhost_get_vq_from_user(struct vhost_dev *dev, void __user *argp,
824 struct vhost_virtqueue **vq, u32 *id)
825{
826 u32 __user *idxp = argp;
827 u32 idx;
828 long r;
829
830 r = get_user(idx, idxp);
831 if (r < 0)
832 return r;
833
834 if (idx >= dev->nvqs)
835 return -ENOBUFS;
836
837 idx = array_index_nospec(idx, dev->nvqs);
838
839 *vq = dev->vqs[idx];
840 *id = idx;
841 return 0;
842}
843
844/* Caller must have device mutex */
845long vhost_worker_ioctl(struct vhost_dev *dev, unsigned int ioctl,
846 void __user *argp)
847{
848 struct vhost_vring_worker ring_worker;
849 struct vhost_worker_state state;
850 struct vhost_worker *worker;
851 struct vhost_virtqueue *vq;
852 long ret;
853 u32 idx;
854
855 if (!dev->use_worker)
856 return -EINVAL;
857
858 if (!vhost_dev_has_owner(dev))
859 return -EINVAL;
860
861 ret = vhost_dev_check_owner(dev);
862 if (ret)
863 return ret;
864
865 switch (ioctl) {
866 /* dev worker ioctls */
867 case VHOST_NEW_WORKER:
868 ret = vhost_new_worker(dev, &state);
869 if (!ret && copy_to_user(argp, &state, sizeof(state)))
870 ret = -EFAULT;
871 return ret;
872 case VHOST_FREE_WORKER:
873 if (copy_from_user(&state, argp, sizeof(state)))
874 return -EFAULT;
875 return vhost_free_worker(dev, &state);
876 /* vring worker ioctls */
877 case VHOST_ATTACH_VRING_WORKER:
878 case VHOST_GET_VRING_WORKER:
879 break;
880 default:
881 return -ENOIOCTLCMD;
882 }
883
884 ret = vhost_get_vq_from_user(dev, argp, &vq, &idx);
885 if (ret)
886 return ret;
887
888 switch (ioctl) {
889 case VHOST_ATTACH_VRING_WORKER:
890 if (copy_from_user(&ring_worker, argp, sizeof(ring_worker))) {
891 ret = -EFAULT;
892 break;
893 }
894
895 ret = vhost_vq_attach_worker(vq, &ring_worker);
896 break;
897 case VHOST_GET_VRING_WORKER:
898 worker = rcu_dereference_check(vq->worker,
899 lockdep_is_held(&dev->mutex));
900 if (!worker) {
901 ret = -EINVAL;
902 break;
903 }
904
905 ring_worker.index = idx;
906 ring_worker.worker_id = worker->id;
907
908 if (copy_to_user(argp, &ring_worker, sizeof(ring_worker)))
909 ret = -EFAULT;
910 break;
911 default:
912 ret = -ENOIOCTLCMD;
913 break;
914 }
915
916 return ret;
917}
918EXPORT_SYMBOL_GPL(vhost_worker_ioctl);
919
920/* Caller should have device mutex */
921long vhost_dev_set_owner(struct vhost_dev *dev)
922{
923 struct vhost_worker *worker;
924 int err, i;
925
926 /* Is there an owner already? */
927 if (vhost_dev_has_owner(dev)) {
928 err = -EBUSY;
929 goto err_mm;
930 }
931
932 vhost_attach_mm(dev);
933
934 err = vhost_dev_alloc_iovecs(dev);
935 if (err)
936 goto err_iovecs;
937
938 if (dev->use_worker) {
939 /*
940 * This should be done last, because vsock can queue work
941 * before VHOST_SET_OWNER so it simplifies the failure path
942 * below since we don't have to worry about vsock queueing
943 * while we free the worker.
944 */
945 worker = vhost_worker_create(dev);
946 if (!worker) {
947 err = -ENOMEM;
948 goto err_worker;
949 }
950
951 for (i = 0; i < dev->nvqs; i++)
952 __vhost_vq_attach_worker(dev->vqs[i], worker);
953 }
954
955 return 0;
956
957err_worker:
958 vhost_dev_free_iovecs(dev);
959err_iovecs:
960 vhost_detach_mm(dev);
961err_mm:
962 return err;
963}
964EXPORT_SYMBOL_GPL(vhost_dev_set_owner);
965
966static struct vhost_iotlb *iotlb_alloc(void)
967{
968 return vhost_iotlb_alloc(max_iotlb_entries,
969 VHOST_IOTLB_FLAG_RETIRE);
970}
971
972struct vhost_iotlb *vhost_dev_reset_owner_prepare(void)
973{
974 return iotlb_alloc();
975}
976EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare);
977
978/* Caller should have device mutex */
979void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_iotlb *umem)
980{
981 int i;
982
983 vhost_dev_cleanup(dev);
984
985 dev->umem = umem;
986 /* We don't need VQ locks below since vhost_dev_cleanup makes sure
987 * VQs aren't running.
988 */
989 for (i = 0; i < dev->nvqs; ++i)
990 dev->vqs[i]->umem = umem;
991}
992EXPORT_SYMBOL_GPL(vhost_dev_reset_owner);
993
994void vhost_dev_stop(struct vhost_dev *dev)
995{
996 int i;
997
998 for (i = 0; i < dev->nvqs; ++i) {
999 if (dev->vqs[i]->kick && dev->vqs[i]->handle_kick)
1000 vhost_poll_stop(&dev->vqs[i]->poll);
1001 }
1002
1003 vhost_dev_flush(dev);
1004}
1005EXPORT_SYMBOL_GPL(vhost_dev_stop);
1006
1007void vhost_clear_msg(struct vhost_dev *dev)
1008{
1009 struct vhost_msg_node *node, *n;
1010
1011 spin_lock(&dev->iotlb_lock);
1012
1013 list_for_each_entry_safe(node, n, &dev->read_list, node) {
1014 list_del(&node->node);
1015 kfree(node);
1016 }
1017
1018 list_for_each_entry_safe(node, n, &dev->pending_list, node) {
1019 list_del(&node->node);
1020 kfree(node);
1021 }
1022
1023 spin_unlock(&dev->iotlb_lock);
1024}
1025EXPORT_SYMBOL_GPL(vhost_clear_msg);
1026
1027void vhost_dev_cleanup(struct vhost_dev *dev)
1028{
1029 int i;
1030
1031 for (i = 0; i < dev->nvqs; ++i) {
1032 if (dev->vqs[i]->error_ctx)
1033 eventfd_ctx_put(dev->vqs[i]->error_ctx);
1034 if (dev->vqs[i]->kick)
1035 fput(dev->vqs[i]->kick);
1036 if (dev->vqs[i]->call_ctx.ctx)
1037 eventfd_ctx_put(dev->vqs[i]->call_ctx.ctx);
1038 vhost_vq_reset(dev, dev->vqs[i]);
1039 }
1040 vhost_dev_free_iovecs(dev);
1041 if (dev->log_ctx)
1042 eventfd_ctx_put(dev->log_ctx);
1043 dev->log_ctx = NULL;
1044 /* No one will access memory at this point */
1045 vhost_iotlb_free(dev->umem);
1046 dev->umem = NULL;
1047 vhost_iotlb_free(dev->iotlb);
1048 dev->iotlb = NULL;
1049 vhost_clear_msg(dev);
1050 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
1051 vhost_workers_free(dev);
1052 vhost_detach_mm(dev);
1053}
1054EXPORT_SYMBOL_GPL(vhost_dev_cleanup);
1055
1056static bool log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
1057{
1058 u64 a = addr / VHOST_PAGE_SIZE / 8;
1059
1060 /* Make sure 64 bit math will not overflow. */
1061 if (a > ULONG_MAX - (unsigned long)log_base ||
1062 a + (unsigned long)log_base > ULONG_MAX)
1063 return false;
1064
1065 return access_ok(log_base + a,
1066 (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8);
1067}
1068
1069/* Make sure 64 bit math will not overflow. */
1070static bool vhost_overflow(u64 uaddr, u64 size)
1071{
1072 if (uaddr > ULONG_MAX || size > ULONG_MAX)
1073 return true;
1074
1075 if (!size)
1076 return false;
1077
1078 return uaddr > ULONG_MAX - size + 1;
1079}
1080
1081/* Caller should have vq mutex and device mutex. */
1082static bool vq_memory_access_ok(void __user *log_base, struct vhost_iotlb *umem,
1083 int log_all)
1084{
1085 struct vhost_iotlb_map *map;
1086
1087 if (!umem)
1088 return false;
1089
1090 list_for_each_entry(map, &umem->list, link) {
1091 unsigned long a = map->addr;
1092
1093 if (vhost_overflow(map->addr, map->size))
1094 return false;
1095
1096
1097 if (!access_ok((void __user *)a, map->size))
1098 return false;
1099 else if (log_all && !log_access_ok(log_base,
1100 map->start,
1101 map->size))
1102 return false;
1103 }
1104 return true;
1105}
1106
1107static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq,
1108 u64 addr, unsigned int size,
1109 int type)
1110{
1111 const struct vhost_iotlb_map *map = vq->meta_iotlb[type];
1112
1113 if (!map)
1114 return NULL;
1115
1116 return (void __user *)(uintptr_t)(map->addr + addr - map->start);
1117}
1118
1119/* Can we switch to this memory table? */
1120/* Caller should have device mutex but not vq mutex */
1121static bool memory_access_ok(struct vhost_dev *d, struct vhost_iotlb *umem,
1122 int log_all)
1123{
1124 int i;
1125
1126 for (i = 0; i < d->nvqs; ++i) {
1127 bool ok;
1128 bool log;
1129
1130 mutex_lock(&d->vqs[i]->mutex);
1131 log = log_all || vhost_has_feature(d->vqs[i], VHOST_F_LOG_ALL);
1132 /* If ring is inactive, will check when it's enabled. */
1133 if (d->vqs[i]->private_data)
1134 ok = vq_memory_access_ok(d->vqs[i]->log_base,
1135 umem, log);
1136 else
1137 ok = true;
1138 mutex_unlock(&d->vqs[i]->mutex);
1139 if (!ok)
1140 return false;
1141 }
1142 return true;
1143}
1144
1145static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
1146 struct iovec iov[], int iov_size, int access);
1147
1148static int vhost_copy_to_user(struct vhost_virtqueue *vq, void __user *to,
1149 const void *from, unsigned size)
1150{
1151 int ret;
1152
1153 if (!vq->iotlb)
1154 return __copy_to_user(to, from, size);
1155 else {
1156 /* This function should be called after iotlb
1157 * prefetch, which means we're sure that all vq
1158 * could be access through iotlb. So -EAGAIN should
1159 * not happen in this case.
1160 */
1161 struct iov_iter t;
1162 void __user *uaddr = vhost_vq_meta_fetch(vq,
1163 (u64)(uintptr_t)to, size,
1164 VHOST_ADDR_USED);
1165
1166 if (uaddr)
1167 return __copy_to_user(uaddr, from, size);
1168
1169 ret = translate_desc(vq, (u64)(uintptr_t)to, size, vq->iotlb_iov,
1170 ARRAY_SIZE(vq->iotlb_iov),
1171 VHOST_ACCESS_WO);
1172 if (ret < 0)
1173 goto out;
1174 iov_iter_init(&t, ITER_DEST, vq->iotlb_iov, ret, size);
1175 ret = copy_to_iter(from, size, &t);
1176 if (ret == size)
1177 ret = 0;
1178 }
1179out:
1180 return ret;
1181}
1182
1183static int vhost_copy_from_user(struct vhost_virtqueue *vq, void *to,
1184 void __user *from, unsigned size)
1185{
1186 int ret;
1187
1188 if (!vq->iotlb)
1189 return __copy_from_user(to, from, size);
1190 else {
1191 /* This function should be called after iotlb
1192 * prefetch, which means we're sure that vq
1193 * could be access through iotlb. So -EAGAIN should
1194 * not happen in this case.
1195 */
1196 void __user *uaddr = vhost_vq_meta_fetch(vq,
1197 (u64)(uintptr_t)from, size,
1198 VHOST_ADDR_DESC);
1199 struct iov_iter f;
1200
1201 if (uaddr)
1202 return __copy_from_user(to, uaddr, size);
1203
1204 ret = translate_desc(vq, (u64)(uintptr_t)from, size, vq->iotlb_iov,
1205 ARRAY_SIZE(vq->iotlb_iov),
1206 VHOST_ACCESS_RO);
1207 if (ret < 0) {
1208 vq_err(vq, "IOTLB translation failure: uaddr "
1209 "%p size 0x%llx\n", from,
1210 (unsigned long long) size);
1211 goto out;
1212 }
1213 iov_iter_init(&f, ITER_SOURCE, vq->iotlb_iov, ret, size);
1214 ret = copy_from_iter(to, size, &f);
1215 if (ret == size)
1216 ret = 0;
1217 }
1218
1219out:
1220 return ret;
1221}
1222
1223static void __user *__vhost_get_user_slow(struct vhost_virtqueue *vq,
1224 void __user *addr, unsigned int size,
1225 int type)
1226{
1227 int ret;
1228
1229 ret = translate_desc(vq, (u64)(uintptr_t)addr, size, vq->iotlb_iov,
1230 ARRAY_SIZE(vq->iotlb_iov),
1231 VHOST_ACCESS_RO);
1232 if (ret < 0) {
1233 vq_err(vq, "IOTLB translation failure: uaddr "
1234 "%p size 0x%llx\n", addr,
1235 (unsigned long long) size);
1236 return NULL;
1237 }
1238
1239 if (ret != 1 || vq->iotlb_iov[0].iov_len != size) {
1240 vq_err(vq, "Non atomic userspace memory access: uaddr "
1241 "%p size 0x%llx\n", addr,
1242 (unsigned long long) size);
1243 return NULL;
1244 }
1245
1246 return vq->iotlb_iov[0].iov_base;
1247}
1248
1249/* This function should be called after iotlb
1250 * prefetch, which means we're sure that vq
1251 * could be access through iotlb. So -EAGAIN should
1252 * not happen in this case.
1253 */
1254static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq,
1255 void __user *addr, unsigned int size,
1256 int type)
1257{
1258 void __user *uaddr = vhost_vq_meta_fetch(vq,
1259 (u64)(uintptr_t)addr, size, type);
1260 if (uaddr)
1261 return uaddr;
1262
1263 return __vhost_get_user_slow(vq, addr, size, type);
1264}
1265
1266#define vhost_put_user(vq, x, ptr) \
1267({ \
1268 int ret; \
1269 if (!vq->iotlb) { \
1270 ret = __put_user(x, ptr); \
1271 } else { \
1272 __typeof__(ptr) to = \
1273 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
1274 sizeof(*ptr), VHOST_ADDR_USED); \
1275 if (to != NULL) \
1276 ret = __put_user(x, to); \
1277 else \
1278 ret = -EFAULT; \
1279 } \
1280 ret; \
1281})
1282
1283static inline int vhost_put_avail_event(struct vhost_virtqueue *vq)
1284{
1285 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx),
1286 vhost_avail_event(vq));
1287}
1288
1289static inline int vhost_put_used(struct vhost_virtqueue *vq,
1290 struct vring_used_elem *head, int idx,
1291 int count)
1292{
1293 return vhost_copy_to_user(vq, vq->used->ring + idx, head,
1294 count * sizeof(*head));
1295}
1296
1297static inline int vhost_put_used_flags(struct vhost_virtqueue *vq)
1298
1299{
1300 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags),
1301 &vq->used->flags);
1302}
1303
1304static inline int vhost_put_used_idx(struct vhost_virtqueue *vq)
1305
1306{
1307 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx),
1308 &vq->used->idx);
1309}
1310
1311#define vhost_get_user(vq, x, ptr, type) \
1312({ \
1313 int ret; \
1314 if (!vq->iotlb) { \
1315 ret = __get_user(x, ptr); \
1316 } else { \
1317 __typeof__(ptr) from = \
1318 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
1319 sizeof(*ptr), \
1320 type); \
1321 if (from != NULL) \
1322 ret = __get_user(x, from); \
1323 else \
1324 ret = -EFAULT; \
1325 } \
1326 ret; \
1327})
1328
1329#define vhost_get_avail(vq, x, ptr) \
1330 vhost_get_user(vq, x, ptr, VHOST_ADDR_AVAIL)
1331
1332#define vhost_get_used(vq, x, ptr) \
1333 vhost_get_user(vq, x, ptr, VHOST_ADDR_USED)
1334
1335static void vhost_dev_lock_vqs(struct vhost_dev *d)
1336{
1337 int i = 0;
1338 for (i = 0; i < d->nvqs; ++i)
1339 mutex_lock_nested(&d->vqs[i]->mutex, i);
1340}
1341
1342static void vhost_dev_unlock_vqs(struct vhost_dev *d)
1343{
1344 int i = 0;
1345 for (i = 0; i < d->nvqs; ++i)
1346 mutex_unlock(&d->vqs[i]->mutex);
1347}
1348
1349static inline int vhost_get_avail_idx(struct vhost_virtqueue *vq)
1350{
1351 __virtio16 idx;
1352 int r;
1353
1354 r = vhost_get_avail(vq, idx, &vq->avail->idx);
1355 if (unlikely(r < 0)) {
1356 vq_err(vq, "Failed to access available index at %p (%d)\n",
1357 &vq->avail->idx, r);
1358 return r;
1359 }
1360
1361 /* Check it isn't doing very strange thing with available indexes */
1362 vq->avail_idx = vhost16_to_cpu(vq, idx);
1363 if (unlikely((u16)(vq->avail_idx - vq->last_avail_idx) > vq->num)) {
1364 vq_err(vq, "Invalid available index change from %u to %u",
1365 vq->last_avail_idx, vq->avail_idx);
1366 return -EINVAL;
1367 }
1368
1369 /* We're done if there is nothing new */
1370 if (vq->avail_idx == vq->last_avail_idx)
1371 return 0;
1372
1373 /*
1374 * We updated vq->avail_idx so we need a memory barrier between
1375 * the index read above and the caller reading avail ring entries.
1376 */
1377 smp_rmb();
1378 return 1;
1379}
1380
1381static inline int vhost_get_avail_head(struct vhost_virtqueue *vq,
1382 __virtio16 *head, int idx)
1383{
1384 return vhost_get_avail(vq, *head,
1385 &vq->avail->ring[idx & (vq->num - 1)]);
1386}
1387
1388static inline int vhost_get_avail_flags(struct vhost_virtqueue *vq,
1389 __virtio16 *flags)
1390{
1391 return vhost_get_avail(vq, *flags, &vq->avail->flags);
1392}
1393
1394static inline int vhost_get_used_event(struct vhost_virtqueue *vq,
1395 __virtio16 *event)
1396{
1397 return vhost_get_avail(vq, *event, vhost_used_event(vq));
1398}
1399
1400static inline int vhost_get_used_idx(struct vhost_virtqueue *vq,
1401 __virtio16 *idx)
1402{
1403 return vhost_get_used(vq, *idx, &vq->used->idx);
1404}
1405
1406static inline int vhost_get_desc(struct vhost_virtqueue *vq,
1407 struct vring_desc *desc, int idx)
1408{
1409 return vhost_copy_from_user(vq, desc, vq->desc + idx, sizeof(*desc));
1410}
1411
1412static void vhost_iotlb_notify_vq(struct vhost_dev *d,
1413 struct vhost_iotlb_msg *msg)
1414{
1415 struct vhost_msg_node *node, *n;
1416
1417 spin_lock(&d->iotlb_lock);
1418
1419 list_for_each_entry_safe(node, n, &d->pending_list, node) {
1420 struct vhost_iotlb_msg *vq_msg = &node->msg.iotlb;
1421 if (msg->iova <= vq_msg->iova &&
1422 msg->iova + msg->size - 1 >= vq_msg->iova &&
1423 vq_msg->type == VHOST_IOTLB_MISS) {
1424 vhost_poll_queue(&node->vq->poll);
1425 list_del(&node->node);
1426 kfree(node);
1427 }
1428 }
1429
1430 spin_unlock(&d->iotlb_lock);
1431}
1432
1433static bool umem_access_ok(u64 uaddr, u64 size, int access)
1434{
1435 unsigned long a = uaddr;
1436
1437 /* Make sure 64 bit math will not overflow. */
1438 if (vhost_overflow(uaddr, size))
1439 return false;
1440
1441 if ((access & VHOST_ACCESS_RO) &&
1442 !access_ok((void __user *)a, size))
1443 return false;
1444 if ((access & VHOST_ACCESS_WO) &&
1445 !access_ok((void __user *)a, size))
1446 return false;
1447 return true;
1448}
1449
1450static int vhost_process_iotlb_msg(struct vhost_dev *dev, u32 asid,
1451 struct vhost_iotlb_msg *msg)
1452{
1453 int ret = 0;
1454
1455 if (asid != 0)
1456 return -EINVAL;
1457
1458 mutex_lock(&dev->mutex);
1459 vhost_dev_lock_vqs(dev);
1460 switch (msg->type) {
1461 case VHOST_IOTLB_UPDATE:
1462 if (!dev->iotlb) {
1463 ret = -EFAULT;
1464 break;
1465 }
1466 if (!umem_access_ok(msg->uaddr, msg->size, msg->perm)) {
1467 ret = -EFAULT;
1468 break;
1469 }
1470 vhost_vq_meta_reset(dev);
1471 if (vhost_iotlb_add_range(dev->iotlb, msg->iova,
1472 msg->iova + msg->size - 1,
1473 msg->uaddr, msg->perm)) {
1474 ret = -ENOMEM;
1475 break;
1476 }
1477 vhost_iotlb_notify_vq(dev, msg);
1478 break;
1479 case VHOST_IOTLB_INVALIDATE:
1480 if (!dev->iotlb) {
1481 ret = -EFAULT;
1482 break;
1483 }
1484 vhost_vq_meta_reset(dev);
1485 vhost_iotlb_del_range(dev->iotlb, msg->iova,
1486 msg->iova + msg->size - 1);
1487 break;
1488 default:
1489 ret = -EINVAL;
1490 break;
1491 }
1492
1493 vhost_dev_unlock_vqs(dev);
1494 mutex_unlock(&dev->mutex);
1495
1496 return ret;
1497}
1498ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
1499 struct iov_iter *from)
1500{
1501 struct vhost_iotlb_msg msg;
1502 size_t offset;
1503 int type, ret;
1504 u32 asid = 0;
1505
1506 ret = copy_from_iter(&type, sizeof(type), from);
1507 if (ret != sizeof(type)) {
1508 ret = -EINVAL;
1509 goto done;
1510 }
1511
1512 switch (type) {
1513 case VHOST_IOTLB_MSG:
1514 /* There maybe a hole after type for V1 message type,
1515 * so skip it here.
1516 */
1517 offset = offsetof(struct vhost_msg, iotlb) - sizeof(int);
1518 break;
1519 case VHOST_IOTLB_MSG_V2:
1520 if (vhost_backend_has_feature(dev->vqs[0],
1521 VHOST_BACKEND_F_IOTLB_ASID)) {
1522 ret = copy_from_iter(&asid, sizeof(asid), from);
1523 if (ret != sizeof(asid)) {
1524 ret = -EINVAL;
1525 goto done;
1526 }
1527 offset = 0;
1528 } else
1529 offset = sizeof(__u32);
1530 break;
1531 default:
1532 ret = -EINVAL;
1533 goto done;
1534 }
1535
1536 iov_iter_advance(from, offset);
1537 ret = copy_from_iter(&msg, sizeof(msg), from);
1538 if (ret != sizeof(msg)) {
1539 ret = -EINVAL;
1540 goto done;
1541 }
1542
1543 if (msg.type == VHOST_IOTLB_UPDATE && msg.size == 0) {
1544 ret = -EINVAL;
1545 goto done;
1546 }
1547
1548 if (dev->msg_handler)
1549 ret = dev->msg_handler(dev, asid, &msg);
1550 else
1551 ret = vhost_process_iotlb_msg(dev, asid, &msg);
1552 if (ret) {
1553 ret = -EFAULT;
1554 goto done;
1555 }
1556
1557 ret = (type == VHOST_IOTLB_MSG) ? sizeof(struct vhost_msg) :
1558 sizeof(struct vhost_msg_v2);
1559done:
1560 return ret;
1561}
1562EXPORT_SYMBOL(vhost_chr_write_iter);
1563
1564__poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
1565 poll_table *wait)
1566{
1567 __poll_t mask = 0;
1568
1569 poll_wait(file, &dev->wait, wait);
1570
1571 if (!list_empty(&dev->read_list))
1572 mask |= EPOLLIN | EPOLLRDNORM;
1573
1574 return mask;
1575}
1576EXPORT_SYMBOL(vhost_chr_poll);
1577
1578ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
1579 int noblock)
1580{
1581 DEFINE_WAIT(wait);
1582 struct vhost_msg_node *node;
1583 ssize_t ret = 0;
1584 unsigned size = sizeof(struct vhost_msg);
1585
1586 if (iov_iter_count(to) < size)
1587 return 0;
1588
1589 while (1) {
1590 if (!noblock)
1591 prepare_to_wait(&dev->wait, &wait,
1592 TASK_INTERRUPTIBLE);
1593
1594 node = vhost_dequeue_msg(dev, &dev->read_list);
1595 if (node)
1596 break;
1597 if (noblock) {
1598 ret = -EAGAIN;
1599 break;
1600 }
1601 if (signal_pending(current)) {
1602 ret = -ERESTARTSYS;
1603 break;
1604 }
1605 if (!dev->iotlb) {
1606 ret = -EBADFD;
1607 break;
1608 }
1609
1610 schedule();
1611 }
1612
1613 if (!noblock)
1614 finish_wait(&dev->wait, &wait);
1615
1616 if (node) {
1617 struct vhost_iotlb_msg *msg;
1618 void *start = &node->msg;
1619
1620 switch (node->msg.type) {
1621 case VHOST_IOTLB_MSG:
1622 size = sizeof(node->msg);
1623 msg = &node->msg.iotlb;
1624 break;
1625 case VHOST_IOTLB_MSG_V2:
1626 size = sizeof(node->msg_v2);
1627 msg = &node->msg_v2.iotlb;
1628 break;
1629 default:
1630 BUG();
1631 break;
1632 }
1633
1634 ret = copy_to_iter(start, size, to);
1635 if (ret != size || msg->type != VHOST_IOTLB_MISS) {
1636 kfree(node);
1637 return ret;
1638 }
1639 vhost_enqueue_msg(dev, &dev->pending_list, node);
1640 }
1641
1642 return ret;
1643}
1644EXPORT_SYMBOL_GPL(vhost_chr_read_iter);
1645
1646static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access)
1647{
1648 struct vhost_dev *dev = vq->dev;
1649 struct vhost_msg_node *node;
1650 struct vhost_iotlb_msg *msg;
1651 bool v2 = vhost_backend_has_feature(vq, VHOST_BACKEND_F_IOTLB_MSG_V2);
1652
1653 node = vhost_new_msg(vq, v2 ? VHOST_IOTLB_MSG_V2 : VHOST_IOTLB_MSG);
1654 if (!node)
1655 return -ENOMEM;
1656
1657 if (v2) {
1658 node->msg_v2.type = VHOST_IOTLB_MSG_V2;
1659 msg = &node->msg_v2.iotlb;
1660 } else {
1661 msg = &node->msg.iotlb;
1662 }
1663
1664 msg->type = VHOST_IOTLB_MISS;
1665 msg->iova = iova;
1666 msg->perm = access;
1667
1668 vhost_enqueue_msg(dev, &dev->read_list, node);
1669
1670 return 0;
1671}
1672
1673static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
1674 vring_desc_t __user *desc,
1675 vring_avail_t __user *avail,
1676 vring_used_t __user *used)
1677
1678{
1679 /* If an IOTLB device is present, the vring addresses are
1680 * GIOVAs. Access validation occurs at prefetch time. */
1681 if (vq->iotlb)
1682 return true;
1683
1684 return access_ok(desc, vhost_get_desc_size(vq, num)) &&
1685 access_ok(avail, vhost_get_avail_size(vq, num)) &&
1686 access_ok(used, vhost_get_used_size(vq, num));
1687}
1688
1689static void vhost_vq_meta_update(struct vhost_virtqueue *vq,
1690 const struct vhost_iotlb_map *map,
1691 int type)
1692{
1693 int access = (type == VHOST_ADDR_USED) ?
1694 VHOST_ACCESS_WO : VHOST_ACCESS_RO;
1695
1696 if (likely(map->perm & access))
1697 vq->meta_iotlb[type] = map;
1698}
1699
1700static bool iotlb_access_ok(struct vhost_virtqueue *vq,
1701 int access, u64 addr, u64 len, int type)
1702{
1703 const struct vhost_iotlb_map *map;
1704 struct vhost_iotlb *umem = vq->iotlb;
1705 u64 s = 0, size, orig_addr = addr, last = addr + len - 1;
1706
1707 if (vhost_vq_meta_fetch(vq, addr, len, type))
1708 return true;
1709
1710 while (len > s) {
1711 map = vhost_iotlb_itree_first(umem, addr, last);
1712 if (map == NULL || map->start > addr) {
1713 vhost_iotlb_miss(vq, addr, access);
1714 return false;
1715 } else if (!(map->perm & access)) {
1716 /* Report the possible access violation by
1717 * request another translation from userspace.
1718 */
1719 return false;
1720 }
1721
1722 size = map->size - addr + map->start;
1723
1724 if (orig_addr == addr && size >= len)
1725 vhost_vq_meta_update(vq, map, type);
1726
1727 s += size;
1728 addr += size;
1729 }
1730
1731 return true;
1732}
1733
1734int vq_meta_prefetch(struct vhost_virtqueue *vq)
1735{
1736 unsigned int num = vq->num;
1737
1738 if (!vq->iotlb)
1739 return 1;
1740
1741 return iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->desc,
1742 vhost_get_desc_size(vq, num), VHOST_ADDR_DESC) &&
1743 iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->avail,
1744 vhost_get_avail_size(vq, num),
1745 VHOST_ADDR_AVAIL) &&
1746 iotlb_access_ok(vq, VHOST_MAP_WO, (u64)(uintptr_t)vq->used,
1747 vhost_get_used_size(vq, num), VHOST_ADDR_USED);
1748}
1749EXPORT_SYMBOL_GPL(vq_meta_prefetch);
1750
1751/* Can we log writes? */
1752/* Caller should have device mutex but not vq mutex */
1753bool vhost_log_access_ok(struct vhost_dev *dev)
1754{
1755 return memory_access_ok(dev, dev->umem, 1);
1756}
1757EXPORT_SYMBOL_GPL(vhost_log_access_ok);
1758
1759static bool vq_log_used_access_ok(struct vhost_virtqueue *vq,
1760 void __user *log_base,
1761 bool log_used,
1762 u64 log_addr)
1763{
1764 /* If an IOTLB device is present, log_addr is a GIOVA that
1765 * will never be logged by log_used(). */
1766 if (vq->iotlb)
1767 return true;
1768
1769 return !log_used || log_access_ok(log_base, log_addr,
1770 vhost_get_used_size(vq, vq->num));
1771}
1772
1773/* Verify access for write logging. */
1774/* Caller should have vq mutex and device mutex */
1775static bool vq_log_access_ok(struct vhost_virtqueue *vq,
1776 void __user *log_base)
1777{
1778 return vq_memory_access_ok(log_base, vq->umem,
1779 vhost_has_feature(vq, VHOST_F_LOG_ALL)) &&
1780 vq_log_used_access_ok(vq, log_base, vq->log_used, vq->log_addr);
1781}
1782
1783/* Can we start vq? */
1784/* Caller should have vq mutex and device mutex */
1785bool vhost_vq_access_ok(struct vhost_virtqueue *vq)
1786{
1787 if (!vq_log_access_ok(vq, vq->log_base))
1788 return false;
1789
1790 return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used);
1791}
1792EXPORT_SYMBOL_GPL(vhost_vq_access_ok);
1793
1794static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
1795{
1796 struct vhost_memory mem, *newmem;
1797 struct vhost_memory_region *region;
1798 struct vhost_iotlb *newumem, *oldumem;
1799 unsigned long size = offsetof(struct vhost_memory, regions);
1800 int i;
1801
1802 if (copy_from_user(&mem, m, size))
1803 return -EFAULT;
1804 if (mem.padding)
1805 return -EOPNOTSUPP;
1806 if (mem.nregions > max_mem_regions)
1807 return -E2BIG;
1808 newmem = kvzalloc(struct_size(newmem, regions, mem.nregions),
1809 GFP_KERNEL);
1810 if (!newmem)
1811 return -ENOMEM;
1812
1813 memcpy(newmem, &mem, size);
1814 if (copy_from_user(newmem->regions, m->regions,
1815 flex_array_size(newmem, regions, mem.nregions))) {
1816 kvfree(newmem);
1817 return -EFAULT;
1818 }
1819
1820 newumem = iotlb_alloc();
1821 if (!newumem) {
1822 kvfree(newmem);
1823 return -ENOMEM;
1824 }
1825
1826 for (region = newmem->regions;
1827 region < newmem->regions + mem.nregions;
1828 region++) {
1829 if (vhost_iotlb_add_range(newumem,
1830 region->guest_phys_addr,
1831 region->guest_phys_addr +
1832 region->memory_size - 1,
1833 region->userspace_addr,
1834 VHOST_MAP_RW))
1835 goto err;
1836 }
1837
1838 if (!memory_access_ok(d, newumem, 0))
1839 goto err;
1840
1841 oldumem = d->umem;
1842 d->umem = newumem;
1843
1844 /* All memory accesses are done under some VQ mutex. */
1845 for (i = 0; i < d->nvqs; ++i) {
1846 mutex_lock(&d->vqs[i]->mutex);
1847 d->vqs[i]->umem = newumem;
1848 mutex_unlock(&d->vqs[i]->mutex);
1849 }
1850
1851 kvfree(newmem);
1852 vhost_iotlb_free(oldumem);
1853 return 0;
1854
1855err:
1856 vhost_iotlb_free(newumem);
1857 kvfree(newmem);
1858 return -EFAULT;
1859}
1860
1861static long vhost_vring_set_num(struct vhost_dev *d,
1862 struct vhost_virtqueue *vq,
1863 void __user *argp)
1864{
1865 struct vhost_vring_state s;
1866
1867 /* Resizing ring with an active backend?
1868 * You don't want to do that. */
1869 if (vq->private_data)
1870 return -EBUSY;
1871
1872 if (copy_from_user(&s, argp, sizeof s))
1873 return -EFAULT;
1874
1875 if (!s.num || s.num > 0xffff || (s.num & (s.num - 1)))
1876 return -EINVAL;
1877 vq->num = s.num;
1878
1879 return 0;
1880}
1881
1882static long vhost_vring_set_addr(struct vhost_dev *d,
1883 struct vhost_virtqueue *vq,
1884 void __user *argp)
1885{
1886 struct vhost_vring_addr a;
1887
1888 if (copy_from_user(&a, argp, sizeof a))
1889 return -EFAULT;
1890 if (a.flags & ~(0x1 << VHOST_VRING_F_LOG))
1891 return -EOPNOTSUPP;
1892
1893 /* For 32bit, verify that the top 32bits of the user
1894 data are set to zero. */
1895 if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr ||
1896 (u64)(unsigned long)a.used_user_addr != a.used_user_addr ||
1897 (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr)
1898 return -EFAULT;
1899
1900 /* Make sure it's safe to cast pointers to vring types. */
1901 BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE);
1902 BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE);
1903 if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) ||
1904 (a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) ||
1905 (a.log_guest_addr & (VRING_USED_ALIGN_SIZE - 1)))
1906 return -EINVAL;
1907
1908 /* We only verify access here if backend is configured.
1909 * If it is not, we don't as size might not have been setup.
1910 * We will verify when backend is configured. */
1911 if (vq->private_data) {
1912 if (!vq_access_ok(vq, vq->num,
1913 (void __user *)(unsigned long)a.desc_user_addr,
1914 (void __user *)(unsigned long)a.avail_user_addr,
1915 (void __user *)(unsigned long)a.used_user_addr))
1916 return -EINVAL;
1917
1918 /* Also validate log access for used ring if enabled. */
1919 if (!vq_log_used_access_ok(vq, vq->log_base,
1920 a.flags & (0x1 << VHOST_VRING_F_LOG),
1921 a.log_guest_addr))
1922 return -EINVAL;
1923 }
1924
1925 vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG));
1926 vq->desc = (void __user *)(unsigned long)a.desc_user_addr;
1927 vq->avail = (void __user *)(unsigned long)a.avail_user_addr;
1928 vq->log_addr = a.log_guest_addr;
1929 vq->used = (void __user *)(unsigned long)a.used_user_addr;
1930
1931 return 0;
1932}
1933
1934static long vhost_vring_set_num_addr(struct vhost_dev *d,
1935 struct vhost_virtqueue *vq,
1936 unsigned int ioctl,
1937 void __user *argp)
1938{
1939 long r;
1940
1941 mutex_lock(&vq->mutex);
1942
1943 switch (ioctl) {
1944 case VHOST_SET_VRING_NUM:
1945 r = vhost_vring_set_num(d, vq, argp);
1946 break;
1947 case VHOST_SET_VRING_ADDR:
1948 r = vhost_vring_set_addr(d, vq, argp);
1949 break;
1950 default:
1951 BUG();
1952 }
1953
1954 mutex_unlock(&vq->mutex);
1955
1956 return r;
1957}
1958long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
1959{
1960 struct file *eventfp, *filep = NULL;
1961 bool pollstart = false, pollstop = false;
1962 struct eventfd_ctx *ctx = NULL;
1963 struct vhost_virtqueue *vq;
1964 struct vhost_vring_state s;
1965 struct vhost_vring_file f;
1966 u32 idx;
1967 long r;
1968
1969 r = vhost_get_vq_from_user(d, argp, &vq, &idx);
1970 if (r < 0)
1971 return r;
1972
1973 if (ioctl == VHOST_SET_VRING_NUM ||
1974 ioctl == VHOST_SET_VRING_ADDR) {
1975 return vhost_vring_set_num_addr(d, vq, ioctl, argp);
1976 }
1977
1978 mutex_lock(&vq->mutex);
1979
1980 switch (ioctl) {
1981 case VHOST_SET_VRING_BASE:
1982 /* Moving base with an active backend?
1983 * You don't want to do that. */
1984 if (vq->private_data) {
1985 r = -EBUSY;
1986 break;
1987 }
1988 if (copy_from_user(&s, argp, sizeof s)) {
1989 r = -EFAULT;
1990 break;
1991 }
1992 if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) {
1993 vq->last_avail_idx = s.num & 0xffff;
1994 vq->last_used_idx = (s.num >> 16) & 0xffff;
1995 } else {
1996 if (s.num > 0xffff) {
1997 r = -EINVAL;
1998 break;
1999 }
2000 vq->last_avail_idx = s.num;
2001 }
2002 /* Forget the cached index value. */
2003 vq->avail_idx = vq->last_avail_idx;
2004 break;
2005 case VHOST_GET_VRING_BASE:
2006 s.index = idx;
2007 if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
2008 s.num = (u32)vq->last_avail_idx | ((u32)vq->last_used_idx << 16);
2009 else
2010 s.num = vq->last_avail_idx;
2011 if (copy_to_user(argp, &s, sizeof s))
2012 r = -EFAULT;
2013 break;
2014 case VHOST_SET_VRING_KICK:
2015 if (copy_from_user(&f, argp, sizeof f)) {
2016 r = -EFAULT;
2017 break;
2018 }
2019 eventfp = f.fd == VHOST_FILE_UNBIND ? NULL : eventfd_fget(f.fd);
2020 if (IS_ERR(eventfp)) {
2021 r = PTR_ERR(eventfp);
2022 break;
2023 }
2024 if (eventfp != vq->kick) {
2025 pollstop = (filep = vq->kick) != NULL;
2026 pollstart = (vq->kick = eventfp) != NULL;
2027 } else
2028 filep = eventfp;
2029 break;
2030 case VHOST_SET_VRING_CALL:
2031 if (copy_from_user(&f, argp, sizeof f)) {
2032 r = -EFAULT;
2033 break;
2034 }
2035 ctx = f.fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(f.fd);
2036 if (IS_ERR(ctx)) {
2037 r = PTR_ERR(ctx);
2038 break;
2039 }
2040
2041 swap(ctx, vq->call_ctx.ctx);
2042 break;
2043 case VHOST_SET_VRING_ERR:
2044 if (copy_from_user(&f, argp, sizeof f)) {
2045 r = -EFAULT;
2046 break;
2047 }
2048 ctx = f.fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(f.fd);
2049 if (IS_ERR(ctx)) {
2050 r = PTR_ERR(ctx);
2051 break;
2052 }
2053 swap(ctx, vq->error_ctx);
2054 break;
2055 case VHOST_SET_VRING_ENDIAN:
2056 r = vhost_set_vring_endian(vq, argp);
2057 break;
2058 case VHOST_GET_VRING_ENDIAN:
2059 r = vhost_get_vring_endian(vq, idx, argp);
2060 break;
2061 case VHOST_SET_VRING_BUSYLOOP_TIMEOUT:
2062 if (copy_from_user(&s, argp, sizeof(s))) {
2063 r = -EFAULT;
2064 break;
2065 }
2066 vq->busyloop_timeout = s.num;
2067 break;
2068 case VHOST_GET_VRING_BUSYLOOP_TIMEOUT:
2069 s.index = idx;
2070 s.num = vq->busyloop_timeout;
2071 if (copy_to_user(argp, &s, sizeof(s)))
2072 r = -EFAULT;
2073 break;
2074 default:
2075 r = -ENOIOCTLCMD;
2076 }
2077
2078 if (pollstop && vq->handle_kick)
2079 vhost_poll_stop(&vq->poll);
2080
2081 if (!IS_ERR_OR_NULL(ctx))
2082 eventfd_ctx_put(ctx);
2083 if (filep)
2084 fput(filep);
2085
2086 if (pollstart && vq->handle_kick)
2087 r = vhost_poll_start(&vq->poll, vq->kick);
2088
2089 mutex_unlock(&vq->mutex);
2090
2091 if (pollstop && vq->handle_kick)
2092 vhost_dev_flush(vq->poll.dev);
2093 return r;
2094}
2095EXPORT_SYMBOL_GPL(vhost_vring_ioctl);
2096
2097int vhost_init_device_iotlb(struct vhost_dev *d)
2098{
2099 struct vhost_iotlb *niotlb, *oiotlb;
2100 int i;
2101
2102 niotlb = iotlb_alloc();
2103 if (!niotlb)
2104 return -ENOMEM;
2105
2106 oiotlb = d->iotlb;
2107 d->iotlb = niotlb;
2108
2109 for (i = 0; i < d->nvqs; ++i) {
2110 struct vhost_virtqueue *vq = d->vqs[i];
2111
2112 mutex_lock(&vq->mutex);
2113 vq->iotlb = niotlb;
2114 __vhost_vq_meta_reset(vq);
2115 mutex_unlock(&vq->mutex);
2116 }
2117
2118 vhost_iotlb_free(oiotlb);
2119
2120 return 0;
2121}
2122EXPORT_SYMBOL_GPL(vhost_init_device_iotlb);
2123
2124/* Caller must have device mutex */
2125long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
2126{
2127 struct eventfd_ctx *ctx;
2128 u64 p;
2129 long r;
2130 int i, fd;
2131
2132 /* If you are not the owner, you can become one */
2133 if (ioctl == VHOST_SET_OWNER) {
2134 r = vhost_dev_set_owner(d);
2135 goto done;
2136 }
2137
2138 /* You must be the owner to do anything else */
2139 r = vhost_dev_check_owner(d);
2140 if (r)
2141 goto done;
2142
2143 switch (ioctl) {
2144 case VHOST_SET_MEM_TABLE:
2145 r = vhost_set_memory(d, argp);
2146 break;
2147 case VHOST_SET_LOG_BASE:
2148 if (copy_from_user(&p, argp, sizeof p)) {
2149 r = -EFAULT;
2150 break;
2151 }
2152 if ((u64)(unsigned long)p != p) {
2153 r = -EFAULT;
2154 break;
2155 }
2156 for (i = 0; i < d->nvqs; ++i) {
2157 struct vhost_virtqueue *vq;
2158 void __user *base = (void __user *)(unsigned long)p;
2159 vq = d->vqs[i];
2160 mutex_lock(&vq->mutex);
2161 /* If ring is inactive, will check when it's enabled. */
2162 if (vq->private_data && !vq_log_access_ok(vq, base))
2163 r = -EFAULT;
2164 else
2165 vq->log_base = base;
2166 mutex_unlock(&vq->mutex);
2167 }
2168 break;
2169 case VHOST_SET_LOG_FD:
2170 r = get_user(fd, (int __user *)argp);
2171 if (r < 0)
2172 break;
2173 ctx = fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(fd);
2174 if (IS_ERR(ctx)) {
2175 r = PTR_ERR(ctx);
2176 break;
2177 }
2178 swap(ctx, d->log_ctx);
2179 for (i = 0; i < d->nvqs; ++i) {
2180 mutex_lock(&d->vqs[i]->mutex);
2181 d->vqs[i]->log_ctx = d->log_ctx;
2182 mutex_unlock(&d->vqs[i]->mutex);
2183 }
2184 if (ctx)
2185 eventfd_ctx_put(ctx);
2186 break;
2187 default:
2188 r = -ENOIOCTLCMD;
2189 break;
2190 }
2191done:
2192 return r;
2193}
2194EXPORT_SYMBOL_GPL(vhost_dev_ioctl);
2195
2196/* TODO: This is really inefficient. We need something like get_user()
2197 * (instruction directly accesses the data, with an exception table entry
2198 * returning -EFAULT). See Documentation/arch/x86/exception-tables.rst.
2199 */
2200static int set_bit_to_user(int nr, void __user *addr)
2201{
2202 unsigned long log = (unsigned long)addr;
2203 struct page *page;
2204 void *base;
2205 int bit = nr + (log % PAGE_SIZE) * 8;
2206 int r;
2207
2208 r = pin_user_pages_fast(log, 1, FOLL_WRITE, &page);
2209 if (r < 0)
2210 return r;
2211 BUG_ON(r != 1);
2212 base = kmap_atomic(page);
2213 set_bit(bit, base);
2214 kunmap_atomic(base);
2215 unpin_user_pages_dirty_lock(&page, 1, true);
2216 return 0;
2217}
2218
2219static int log_write(void __user *log_base,
2220 u64 write_address, u64 write_length)
2221{
2222 u64 write_page = write_address / VHOST_PAGE_SIZE;
2223 int r;
2224
2225 if (!write_length)
2226 return 0;
2227 write_length += write_address % VHOST_PAGE_SIZE;
2228 for (;;) {
2229 u64 base = (u64)(unsigned long)log_base;
2230 u64 log = base + write_page / 8;
2231 int bit = write_page % 8;
2232 if ((u64)(unsigned long)log != log)
2233 return -EFAULT;
2234 r = set_bit_to_user(bit, (void __user *)(unsigned long)log);
2235 if (r < 0)
2236 return r;
2237 if (write_length <= VHOST_PAGE_SIZE)
2238 break;
2239 write_length -= VHOST_PAGE_SIZE;
2240 write_page += 1;
2241 }
2242 return r;
2243}
2244
2245static int log_write_hva(struct vhost_virtqueue *vq, u64 hva, u64 len)
2246{
2247 struct vhost_iotlb *umem = vq->umem;
2248 struct vhost_iotlb_map *u;
2249 u64 start, end, l, min;
2250 int r;
2251 bool hit = false;
2252
2253 while (len) {
2254 min = len;
2255 /* More than one GPAs can be mapped into a single HVA. So
2256 * iterate all possible umems here to be safe.
2257 */
2258 list_for_each_entry(u, &umem->list, link) {
2259 if (u->addr > hva - 1 + len ||
2260 u->addr - 1 + u->size < hva)
2261 continue;
2262 start = max(u->addr, hva);
2263 end = min(u->addr - 1 + u->size, hva - 1 + len);
2264 l = end - start + 1;
2265 r = log_write(vq->log_base,
2266 u->start + start - u->addr,
2267 l);
2268 if (r < 0)
2269 return r;
2270 hit = true;
2271 min = min(l, min);
2272 }
2273
2274 if (!hit)
2275 return -EFAULT;
2276
2277 len -= min;
2278 hva += min;
2279 }
2280
2281 return 0;
2282}
2283
2284static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len)
2285{
2286 struct iovec *iov = vq->log_iov;
2287 int i, ret;
2288
2289 if (!vq->iotlb)
2290 return log_write(vq->log_base, vq->log_addr + used_offset, len);
2291
2292 ret = translate_desc(vq, (uintptr_t)vq->used + used_offset,
2293 len, iov, 64, VHOST_ACCESS_WO);
2294 if (ret < 0)
2295 return ret;
2296
2297 for (i = 0; i < ret; i++) {
2298 ret = log_write_hva(vq, (uintptr_t)iov[i].iov_base,
2299 iov[i].iov_len);
2300 if (ret)
2301 return ret;
2302 }
2303
2304 return 0;
2305}
2306
2307int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
2308 unsigned int log_num, u64 len, struct iovec *iov, int count)
2309{
2310 int i, r;
2311
2312 /* Make sure data written is seen before log. */
2313 smp_wmb();
2314
2315 if (vq->iotlb) {
2316 for (i = 0; i < count; i++) {
2317 r = log_write_hva(vq, (uintptr_t)iov[i].iov_base,
2318 iov[i].iov_len);
2319 if (r < 0)
2320 return r;
2321 }
2322 return 0;
2323 }
2324
2325 for (i = 0; i < log_num; ++i) {
2326 u64 l = min(log[i].len, len);
2327 r = log_write(vq->log_base, log[i].addr, l);
2328 if (r < 0)
2329 return r;
2330 len -= l;
2331 if (!len) {
2332 if (vq->log_ctx)
2333 eventfd_signal(vq->log_ctx);
2334 return 0;
2335 }
2336 }
2337 /* Length written exceeds what we have stored. This is a bug. */
2338 BUG();
2339 return 0;
2340}
2341EXPORT_SYMBOL_GPL(vhost_log_write);
2342
2343static int vhost_update_used_flags(struct vhost_virtqueue *vq)
2344{
2345 void __user *used;
2346 if (vhost_put_used_flags(vq))
2347 return -EFAULT;
2348 if (unlikely(vq->log_used)) {
2349 /* Make sure the flag is seen before log. */
2350 smp_wmb();
2351 /* Log used flag write. */
2352 used = &vq->used->flags;
2353 log_used(vq, (used - (void __user *)vq->used),
2354 sizeof vq->used->flags);
2355 if (vq->log_ctx)
2356 eventfd_signal(vq->log_ctx);
2357 }
2358 return 0;
2359}
2360
2361static int vhost_update_avail_event(struct vhost_virtqueue *vq)
2362{
2363 if (vhost_put_avail_event(vq))
2364 return -EFAULT;
2365 if (unlikely(vq->log_used)) {
2366 void __user *used;
2367 /* Make sure the event is seen before log. */
2368 smp_wmb();
2369 /* Log avail event write */
2370 used = vhost_avail_event(vq);
2371 log_used(vq, (used - (void __user *)vq->used),
2372 sizeof *vhost_avail_event(vq));
2373 if (vq->log_ctx)
2374 eventfd_signal(vq->log_ctx);
2375 }
2376 return 0;
2377}
2378
2379int vhost_vq_init_access(struct vhost_virtqueue *vq)
2380{
2381 __virtio16 last_used_idx;
2382 int r;
2383 bool is_le = vq->is_le;
2384
2385 if (!vq->private_data)
2386 return 0;
2387
2388 vhost_init_is_le(vq);
2389
2390 r = vhost_update_used_flags(vq);
2391 if (r)
2392 goto err;
2393 vq->signalled_used_valid = false;
2394 if (!vq->iotlb &&
2395 !access_ok(&vq->used->idx, sizeof vq->used->idx)) {
2396 r = -EFAULT;
2397 goto err;
2398 }
2399 r = vhost_get_used_idx(vq, &last_used_idx);
2400 if (r) {
2401 vq_err(vq, "Can't access used idx at %p\n",
2402 &vq->used->idx);
2403 goto err;
2404 }
2405 vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx);
2406 return 0;
2407
2408err:
2409 vq->is_le = is_le;
2410 return r;
2411}
2412EXPORT_SYMBOL_GPL(vhost_vq_init_access);
2413
2414static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
2415 struct iovec iov[], int iov_size, int access)
2416{
2417 const struct vhost_iotlb_map *map;
2418 struct vhost_dev *dev = vq->dev;
2419 struct vhost_iotlb *umem = dev->iotlb ? dev->iotlb : dev->umem;
2420 struct iovec *_iov;
2421 u64 s = 0, last = addr + len - 1;
2422 int ret = 0;
2423
2424 while ((u64)len > s) {
2425 u64 size;
2426 if (unlikely(ret >= iov_size)) {
2427 ret = -ENOBUFS;
2428 break;
2429 }
2430
2431 map = vhost_iotlb_itree_first(umem, addr, last);
2432 if (map == NULL || map->start > addr) {
2433 if (umem != dev->iotlb) {
2434 ret = -EFAULT;
2435 break;
2436 }
2437 ret = -EAGAIN;
2438 break;
2439 } else if (!(map->perm & access)) {
2440 ret = -EPERM;
2441 break;
2442 }
2443
2444 _iov = iov + ret;
2445 size = map->size - addr + map->start;
2446 _iov->iov_len = min((u64)len - s, size);
2447 _iov->iov_base = (void __user *)(unsigned long)
2448 (map->addr + addr - map->start);
2449 s += size;
2450 addr += size;
2451 ++ret;
2452 }
2453
2454 if (ret == -EAGAIN)
2455 vhost_iotlb_miss(vq, addr, access);
2456 return ret;
2457}
2458
2459/* Each buffer in the virtqueues is actually a chain of descriptors. This
2460 * function returns the next descriptor in the chain,
2461 * or -1U if we're at the end. */
2462static unsigned next_desc(struct vhost_virtqueue *vq, struct vring_desc *desc)
2463{
2464 unsigned int next;
2465
2466 /* If this descriptor says it doesn't chain, we're done. */
2467 if (!(desc->flags & cpu_to_vhost16(vq, VRING_DESC_F_NEXT)))
2468 return -1U;
2469
2470 /* Check they're not leading us off end of descriptors. */
2471 next = vhost16_to_cpu(vq, READ_ONCE(desc->next));
2472 return next;
2473}
2474
2475static int get_indirect(struct vhost_virtqueue *vq,
2476 struct iovec iov[], unsigned int iov_size,
2477 unsigned int *out_num, unsigned int *in_num,
2478 struct vhost_log *log, unsigned int *log_num,
2479 struct vring_desc *indirect)
2480{
2481 struct vring_desc desc;
2482 unsigned int i = 0, count, found = 0;
2483 u32 len = vhost32_to_cpu(vq, indirect->len);
2484 struct iov_iter from;
2485 int ret, access;
2486
2487 /* Sanity check */
2488 if (unlikely(len % sizeof desc)) {
2489 vq_err(vq, "Invalid length in indirect descriptor: "
2490 "len 0x%llx not multiple of 0x%zx\n",
2491 (unsigned long long)len,
2492 sizeof desc);
2493 return -EINVAL;
2494 }
2495
2496 ret = translate_desc(vq, vhost64_to_cpu(vq, indirect->addr), len, vq->indirect,
2497 UIO_MAXIOV, VHOST_ACCESS_RO);
2498 if (unlikely(ret < 0)) {
2499 if (ret != -EAGAIN)
2500 vq_err(vq, "Translation failure %d in indirect.\n", ret);
2501 return ret;
2502 }
2503 iov_iter_init(&from, ITER_SOURCE, vq->indirect, ret, len);
2504 count = len / sizeof desc;
2505 /* Buffers are chained via a 16 bit next field, so
2506 * we can have at most 2^16 of these. */
2507 if (unlikely(count > USHRT_MAX + 1)) {
2508 vq_err(vq, "Indirect buffer length too big: %d\n",
2509 indirect->len);
2510 return -E2BIG;
2511 }
2512
2513 do {
2514 unsigned iov_count = *in_num + *out_num;
2515 if (unlikely(++found > count)) {
2516 vq_err(vq, "Loop detected: last one at %u "
2517 "indirect size %u\n",
2518 i, count);
2519 return -EINVAL;
2520 }
2521 if (unlikely(!copy_from_iter_full(&desc, sizeof(desc), &from))) {
2522 vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
2523 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
2524 return -EINVAL;
2525 }
2526 if (unlikely(desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT))) {
2527 vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n",
2528 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
2529 return -EINVAL;
2530 }
2531
2532 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
2533 access = VHOST_ACCESS_WO;
2534 else
2535 access = VHOST_ACCESS_RO;
2536
2537 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
2538 vhost32_to_cpu(vq, desc.len), iov + iov_count,
2539 iov_size - iov_count, access);
2540 if (unlikely(ret < 0)) {
2541 if (ret != -EAGAIN)
2542 vq_err(vq, "Translation failure %d indirect idx %d\n",
2543 ret, i);
2544 return ret;
2545 }
2546 /* If this is an input descriptor, increment that count. */
2547 if (access == VHOST_ACCESS_WO) {
2548 *in_num += ret;
2549 if (unlikely(log && ret)) {
2550 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
2551 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
2552 ++*log_num;
2553 }
2554 } else {
2555 /* If it's an output descriptor, they're all supposed
2556 * to come before any input descriptors. */
2557 if (unlikely(*in_num)) {
2558 vq_err(vq, "Indirect descriptor "
2559 "has out after in: idx %d\n", i);
2560 return -EINVAL;
2561 }
2562 *out_num += ret;
2563 }
2564 } while ((i = next_desc(vq, &desc)) != -1);
2565 return 0;
2566}
2567
2568/* This looks in the virtqueue and for the first available buffer, and converts
2569 * it to an iovec for convenient access. Since descriptors consist of some
2570 * number of output then some number of input descriptors, it's actually two
2571 * iovecs, but we pack them into one and note how many of each there were.
2572 *
2573 * This function returns the descriptor number found, or vq->num (which is
2574 * never a valid descriptor number) if none was found. A negative code is
2575 * returned on error. */
2576int vhost_get_vq_desc(struct vhost_virtqueue *vq,
2577 struct iovec iov[], unsigned int iov_size,
2578 unsigned int *out_num, unsigned int *in_num,
2579 struct vhost_log *log, unsigned int *log_num)
2580{
2581 struct vring_desc desc;
2582 unsigned int i, head, found = 0;
2583 u16 last_avail_idx = vq->last_avail_idx;
2584 __virtio16 ring_head;
2585 int ret, access;
2586
2587 if (vq->avail_idx == vq->last_avail_idx) {
2588 ret = vhost_get_avail_idx(vq);
2589 if (unlikely(ret < 0))
2590 return ret;
2591
2592 if (!ret)
2593 return vq->num;
2594 }
2595
2596 /* Grab the next descriptor number they're advertising, and increment
2597 * the index we've seen. */
2598 if (unlikely(vhost_get_avail_head(vq, &ring_head, last_avail_idx))) {
2599 vq_err(vq, "Failed to read head: idx %d address %p\n",
2600 last_avail_idx,
2601 &vq->avail->ring[last_avail_idx % vq->num]);
2602 return -EFAULT;
2603 }
2604
2605 head = vhost16_to_cpu(vq, ring_head);
2606
2607 /* If their number is silly, that's an error. */
2608 if (unlikely(head >= vq->num)) {
2609 vq_err(vq, "Guest says index %u > %u is available",
2610 head, vq->num);
2611 return -EINVAL;
2612 }
2613
2614 /* When we start there are none of either input nor output. */
2615 *out_num = *in_num = 0;
2616 if (unlikely(log))
2617 *log_num = 0;
2618
2619 i = head;
2620 do {
2621 unsigned iov_count = *in_num + *out_num;
2622 if (unlikely(i >= vq->num)) {
2623 vq_err(vq, "Desc index is %u > %u, head = %u",
2624 i, vq->num, head);
2625 return -EINVAL;
2626 }
2627 if (unlikely(++found > vq->num)) {
2628 vq_err(vq, "Loop detected: last one at %u "
2629 "vq size %u head %u\n",
2630 i, vq->num, head);
2631 return -EINVAL;
2632 }
2633 ret = vhost_get_desc(vq, &desc, i);
2634 if (unlikely(ret)) {
2635 vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
2636 i, vq->desc + i);
2637 return -EFAULT;
2638 }
2639 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT)) {
2640 ret = get_indirect(vq, iov, iov_size,
2641 out_num, in_num,
2642 log, log_num, &desc);
2643 if (unlikely(ret < 0)) {
2644 if (ret != -EAGAIN)
2645 vq_err(vq, "Failure detected "
2646 "in indirect descriptor at idx %d\n", i);
2647 return ret;
2648 }
2649 continue;
2650 }
2651
2652 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
2653 access = VHOST_ACCESS_WO;
2654 else
2655 access = VHOST_ACCESS_RO;
2656 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
2657 vhost32_to_cpu(vq, desc.len), iov + iov_count,
2658 iov_size - iov_count, access);
2659 if (unlikely(ret < 0)) {
2660 if (ret != -EAGAIN)
2661 vq_err(vq, "Translation failure %d descriptor idx %d\n",
2662 ret, i);
2663 return ret;
2664 }
2665 if (access == VHOST_ACCESS_WO) {
2666 /* If this is an input descriptor,
2667 * increment that count. */
2668 *in_num += ret;
2669 if (unlikely(log && ret)) {
2670 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
2671 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
2672 ++*log_num;
2673 }
2674 } else {
2675 /* If it's an output descriptor, they're all supposed
2676 * to come before any input descriptors. */
2677 if (unlikely(*in_num)) {
2678 vq_err(vq, "Descriptor has out after in: "
2679 "idx %d\n", i);
2680 return -EINVAL;
2681 }
2682 *out_num += ret;
2683 }
2684 } while ((i = next_desc(vq, &desc)) != -1);
2685
2686 /* On success, increment avail index. */
2687 vq->last_avail_idx++;
2688
2689 /* Assume notifications from guest are disabled at this point,
2690 * if they aren't we would need to update avail_event index. */
2691 BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY));
2692 return head;
2693}
2694EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
2695
2696/* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
2697void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n)
2698{
2699 vq->last_avail_idx -= n;
2700}
2701EXPORT_SYMBOL_GPL(vhost_discard_vq_desc);
2702
2703/* After we've used one of their buffers, we tell them about it. We'll then
2704 * want to notify the guest, using eventfd. */
2705int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
2706{
2707 struct vring_used_elem heads = {
2708 cpu_to_vhost32(vq, head),
2709 cpu_to_vhost32(vq, len)
2710 };
2711
2712 return vhost_add_used_n(vq, &heads, 1);
2713}
2714EXPORT_SYMBOL_GPL(vhost_add_used);
2715
2716static int __vhost_add_used_n(struct vhost_virtqueue *vq,
2717 struct vring_used_elem *heads,
2718 unsigned count)
2719{
2720 vring_used_elem_t __user *used;
2721 u16 old, new;
2722 int start;
2723
2724 start = vq->last_used_idx & (vq->num - 1);
2725 used = vq->used->ring + start;
2726 if (vhost_put_used(vq, heads, start, count)) {
2727 vq_err(vq, "Failed to write used");
2728 return -EFAULT;
2729 }
2730 if (unlikely(vq->log_used)) {
2731 /* Make sure data is seen before log. */
2732 smp_wmb();
2733 /* Log used ring entry write. */
2734 log_used(vq, ((void __user *)used - (void __user *)vq->used),
2735 count * sizeof *used);
2736 }
2737 old = vq->last_used_idx;
2738 new = (vq->last_used_idx += count);
2739 /* If the driver never bothers to signal in a very long while,
2740 * used index might wrap around. If that happens, invalidate
2741 * signalled_used index we stored. TODO: make sure driver
2742 * signals at least once in 2^16 and remove this. */
2743 if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old)))
2744 vq->signalled_used_valid = false;
2745 return 0;
2746}
2747
2748/* After we've used one of their buffers, we tell them about it. We'll then
2749 * want to notify the guest, using eventfd. */
2750int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
2751 unsigned count)
2752{
2753 int start, n, r;
2754
2755 start = vq->last_used_idx & (vq->num - 1);
2756 n = vq->num - start;
2757 if (n < count) {
2758 r = __vhost_add_used_n(vq, heads, n);
2759 if (r < 0)
2760 return r;
2761 heads += n;
2762 count -= n;
2763 }
2764 r = __vhost_add_used_n(vq, heads, count);
2765
2766 /* Make sure buffer is written before we update index. */
2767 smp_wmb();
2768 if (vhost_put_used_idx(vq)) {
2769 vq_err(vq, "Failed to increment used idx");
2770 return -EFAULT;
2771 }
2772 if (unlikely(vq->log_used)) {
2773 /* Make sure used idx is seen before log. */
2774 smp_wmb();
2775 /* Log used index update. */
2776 log_used(vq, offsetof(struct vring_used, idx),
2777 sizeof vq->used->idx);
2778 if (vq->log_ctx)
2779 eventfd_signal(vq->log_ctx);
2780 }
2781 return r;
2782}
2783EXPORT_SYMBOL_GPL(vhost_add_used_n);
2784
2785static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2786{
2787 __u16 old, new;
2788 __virtio16 event;
2789 bool v;
2790 /* Flush out used index updates. This is paired
2791 * with the barrier that the Guest executes when enabling
2792 * interrupts. */
2793 smp_mb();
2794
2795 if (vhost_has_feature(vq, VIRTIO_F_NOTIFY_ON_EMPTY) &&
2796 unlikely(vq->avail_idx == vq->last_avail_idx))
2797 return true;
2798
2799 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2800 __virtio16 flags;
2801 if (vhost_get_avail_flags(vq, &flags)) {
2802 vq_err(vq, "Failed to get flags");
2803 return true;
2804 }
2805 return !(flags & cpu_to_vhost16(vq, VRING_AVAIL_F_NO_INTERRUPT));
2806 }
2807 old = vq->signalled_used;
2808 v = vq->signalled_used_valid;
2809 new = vq->signalled_used = vq->last_used_idx;
2810 vq->signalled_used_valid = true;
2811
2812 if (unlikely(!v))
2813 return true;
2814
2815 if (vhost_get_used_event(vq, &event)) {
2816 vq_err(vq, "Failed to get used event idx");
2817 return true;
2818 }
2819 return vring_need_event(vhost16_to_cpu(vq, event), new, old);
2820}
2821
2822/* This actually signals the guest, using eventfd. */
2823void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2824{
2825 /* Signal the Guest tell them we used something up. */
2826 if (vq->call_ctx.ctx && vhost_notify(dev, vq))
2827 eventfd_signal(vq->call_ctx.ctx);
2828}
2829EXPORT_SYMBOL_GPL(vhost_signal);
2830
2831/* And here's the combo meal deal. Supersize me! */
2832void vhost_add_used_and_signal(struct vhost_dev *dev,
2833 struct vhost_virtqueue *vq,
2834 unsigned int head, int len)
2835{
2836 vhost_add_used(vq, head, len);
2837 vhost_signal(dev, vq);
2838}
2839EXPORT_SYMBOL_GPL(vhost_add_used_and_signal);
2840
2841/* multi-buffer version of vhost_add_used_and_signal */
2842void vhost_add_used_and_signal_n(struct vhost_dev *dev,
2843 struct vhost_virtqueue *vq,
2844 struct vring_used_elem *heads, unsigned count)
2845{
2846 vhost_add_used_n(vq, heads, count);
2847 vhost_signal(dev, vq);
2848}
2849EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
2850
2851/* return true if we're sure that avaiable ring is empty */
2852bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2853{
2854 int r;
2855
2856 if (vq->avail_idx != vq->last_avail_idx)
2857 return false;
2858
2859 r = vhost_get_avail_idx(vq);
2860
2861 /* Note: we treat error as non-empty here */
2862 return r == 0;
2863}
2864EXPORT_SYMBOL_GPL(vhost_vq_avail_empty);
2865
2866/* OK, now we need to know about added descriptors. */
2867bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2868{
2869 int r;
2870
2871 if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
2872 return false;
2873 vq->used_flags &= ~VRING_USED_F_NO_NOTIFY;
2874 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2875 r = vhost_update_used_flags(vq);
2876 if (r) {
2877 vq_err(vq, "Failed to enable notification at %p: %d\n",
2878 &vq->used->flags, r);
2879 return false;
2880 }
2881 } else {
2882 r = vhost_update_avail_event(vq);
2883 if (r) {
2884 vq_err(vq, "Failed to update avail event index at %p: %d\n",
2885 vhost_avail_event(vq), r);
2886 return false;
2887 }
2888 }
2889 /* They could have slipped one in as we were doing that: make
2890 * sure it's written, then check again. */
2891 smp_mb();
2892
2893 r = vhost_get_avail_idx(vq);
2894 /* Note: we treat error as empty here */
2895 if (unlikely(r < 0))
2896 return false;
2897
2898 return r;
2899}
2900EXPORT_SYMBOL_GPL(vhost_enable_notify);
2901
2902/* We don't need to be notified again. */
2903void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2904{
2905 int r;
2906
2907 if (vq->used_flags & VRING_USED_F_NO_NOTIFY)
2908 return;
2909 vq->used_flags |= VRING_USED_F_NO_NOTIFY;
2910 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2911 r = vhost_update_used_flags(vq);
2912 if (r)
2913 vq_err(vq, "Failed to disable notification at %p: %d\n",
2914 &vq->used->flags, r);
2915 }
2916}
2917EXPORT_SYMBOL_GPL(vhost_disable_notify);
2918
2919/* Create a new message. */
2920struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type)
2921{
2922 /* Make sure all padding within the structure is initialized. */
2923 struct vhost_msg_node *node = kzalloc(sizeof(*node), GFP_KERNEL);
2924 if (!node)
2925 return NULL;
2926
2927 node->vq = vq;
2928 node->msg.type = type;
2929 return node;
2930}
2931EXPORT_SYMBOL_GPL(vhost_new_msg);
2932
2933void vhost_enqueue_msg(struct vhost_dev *dev, struct list_head *head,
2934 struct vhost_msg_node *node)
2935{
2936 spin_lock(&dev->iotlb_lock);
2937 list_add_tail(&node->node, head);
2938 spin_unlock(&dev->iotlb_lock);
2939
2940 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
2941}
2942EXPORT_SYMBOL_GPL(vhost_enqueue_msg);
2943
2944struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
2945 struct list_head *head)
2946{
2947 struct vhost_msg_node *node = NULL;
2948
2949 spin_lock(&dev->iotlb_lock);
2950 if (!list_empty(head)) {
2951 node = list_first_entry(head, struct vhost_msg_node,
2952 node);
2953 list_del(&node->node);
2954 }
2955 spin_unlock(&dev->iotlb_lock);
2956
2957 return node;
2958}
2959EXPORT_SYMBOL_GPL(vhost_dequeue_msg);
2960
2961void vhost_set_backend_features(struct vhost_dev *dev, u64 features)
2962{
2963 struct vhost_virtqueue *vq;
2964 int i;
2965
2966 mutex_lock(&dev->mutex);
2967 for (i = 0; i < dev->nvqs; ++i) {
2968 vq = dev->vqs[i];
2969 mutex_lock(&vq->mutex);
2970 vq->acked_backend_features = features;
2971 mutex_unlock(&vq->mutex);
2972 }
2973 mutex_unlock(&dev->mutex);
2974}
2975EXPORT_SYMBOL_GPL(vhost_set_backend_features);
2976
2977static int __init vhost_init(void)
2978{
2979 return 0;
2980}
2981
2982static void __exit vhost_exit(void)
2983{
2984}
2985
2986module_init(vhost_init);
2987module_exit(vhost_exit);
2988
2989MODULE_VERSION("0.0.1");
2990MODULE_LICENSE("GPL v2");
2991MODULE_AUTHOR("Michael S. Tsirkin");
2992MODULE_DESCRIPTION("Host kernel accelerator for virtio");