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[mirror_ubuntu-bionic-kernel.git] / drivers / vhost / vhost.c
1 /* Copyright (C) 2009 Red Hat, Inc.
2 * Copyright (C) 2006 Rusty Russell IBM Corporation
3 *
4 * Author: Michael S. Tsirkin <mst@redhat.com>
5 *
6 * Inspiration, some code, and most witty comments come from
7 * Documentation/virtual/lguest/lguest.c, by Rusty Russell
8 *
9 * This work is licensed under the terms of the GNU GPL, version 2.
10 *
11 * Generic code for virtio server in host kernel.
12 */
13
14 #include <linux/eventfd.h>
15 #include <linux/vhost.h>
16 #include <linux/uio.h>
17 #include <linux/mm.h>
18 #include <linux/mmu_context.h>
19 #include <linux/miscdevice.h>
20 #include <linux/mutex.h>
21 #include <linux/poll.h>
22 #include <linux/file.h>
23 #include <linux/highmem.h>
24 #include <linux/slab.h>
25 #include <linux/vmalloc.h>
26 #include <linux/kthread.h>
27 #include <linux/cgroup.h>
28 #include <linux/module.h>
29 #include <linux/sort.h>
30 #include <linux/sched/mm.h>
31 #include <linux/sched/signal.h>
32 #include <linux/interval_tree_generic.h>
33 #include <linux/nospec.h>
34
35 #include "vhost.h"
36
37 static ushort max_mem_regions = 64;
38 module_param(max_mem_regions, ushort, 0444);
39 MODULE_PARM_DESC(max_mem_regions,
40 "Maximum number of memory regions in memory map. (default: 64)");
41 static int max_iotlb_entries = 2048;
42 module_param(max_iotlb_entries, int, 0444);
43 MODULE_PARM_DESC(max_iotlb_entries,
44 "Maximum number of iotlb entries. (default: 2048)");
45
46 enum {
47 VHOST_MEMORY_F_LOG = 0x1,
48 };
49
50 #define vhost_used_event(vq) ((__virtio16 __user *)&vq->avail->ring[vq->num])
51 #define vhost_avail_event(vq) ((__virtio16 __user *)&vq->used->ring[vq->num])
52
53 INTERVAL_TREE_DEFINE(struct vhost_umem_node,
54 rb, __u64, __subtree_last,
55 START, LAST, static inline, vhost_umem_interval_tree);
56
57 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
58 static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
59 {
60 vq->user_be = !virtio_legacy_is_little_endian();
61 }
62
63 static void vhost_enable_cross_endian_big(struct vhost_virtqueue *vq)
64 {
65 vq->user_be = true;
66 }
67
68 static void vhost_enable_cross_endian_little(struct vhost_virtqueue *vq)
69 {
70 vq->user_be = false;
71 }
72
73 static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
74 {
75 struct vhost_vring_state s;
76
77 if (vq->private_data)
78 return -EBUSY;
79
80 if (copy_from_user(&s, argp, sizeof(s)))
81 return -EFAULT;
82
83 if (s.num != VHOST_VRING_LITTLE_ENDIAN &&
84 s.num != VHOST_VRING_BIG_ENDIAN)
85 return -EINVAL;
86
87 if (s.num == VHOST_VRING_BIG_ENDIAN)
88 vhost_enable_cross_endian_big(vq);
89 else
90 vhost_enable_cross_endian_little(vq);
91
92 return 0;
93 }
94
95 static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
96 int __user *argp)
97 {
98 struct vhost_vring_state s = {
99 .index = idx,
100 .num = vq->user_be
101 };
102
103 if (copy_to_user(argp, &s, sizeof(s)))
104 return -EFAULT;
105
106 return 0;
107 }
108
109 static void vhost_init_is_le(struct vhost_virtqueue *vq)
110 {
111 /* Note for legacy virtio: user_be is initialized at reset time
112 * according to the host endianness. If userspace does not set an
113 * explicit endianness, the default behavior is native endian, as
114 * expected by legacy virtio.
115 */
116 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1) || !vq->user_be;
117 }
118 #else
119 static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
120 {
121 }
122
123 static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
124 {
125 return -ENOIOCTLCMD;
126 }
127
128 static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
129 int __user *argp)
130 {
131 return -ENOIOCTLCMD;
132 }
133
134 static void vhost_init_is_le(struct vhost_virtqueue *vq)
135 {
136 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1)
137 || virtio_legacy_is_little_endian();
138 }
139 #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
140
141 static void vhost_reset_is_le(struct vhost_virtqueue *vq)
142 {
143 vhost_init_is_le(vq);
144 }
145
146 struct vhost_flush_struct {
147 struct vhost_work work;
148 struct completion wait_event;
149 };
150
151 static void vhost_flush_work(struct vhost_work *work)
152 {
153 struct vhost_flush_struct *s;
154
155 s = container_of(work, struct vhost_flush_struct, work);
156 complete(&s->wait_event);
157 }
158
159 static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
160 poll_table *pt)
161 {
162 struct vhost_poll *poll;
163
164 poll = container_of(pt, struct vhost_poll, table);
165 poll->wqh = wqh;
166 add_wait_queue(wqh, &poll->wait);
167 }
168
169 static int vhost_poll_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync,
170 void *key)
171 {
172 struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait);
173
174 if (!((unsigned long)key & poll->mask))
175 return 0;
176
177 vhost_poll_queue(poll);
178 return 0;
179 }
180
181 void 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 init_waitqueue_head(&work->done);
186 }
187 EXPORT_SYMBOL_GPL(vhost_work_init);
188
189 /* Init poll structure */
190 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
191 unsigned long mask, struct vhost_dev *dev)
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
199 vhost_work_init(&poll->work, fn);
200 }
201 EXPORT_SYMBOL_GPL(vhost_poll_init);
202
203 /* Start polling a file. We add ourselves to file's wait queue. The caller must
204 * keep a reference to a file until after vhost_poll_stop is called. */
205 int vhost_poll_start(struct vhost_poll *poll, struct file *file)
206 {
207 unsigned long mask;
208 int ret = 0;
209
210 if (poll->wqh)
211 return 0;
212
213 mask = file->f_op->poll(file, &poll->table);
214 if (mask)
215 vhost_poll_wakeup(&poll->wait, 0, 0, (void *)mask);
216 if (mask & POLLERR) {
217 vhost_poll_stop(poll);
218 ret = -EINVAL;
219 }
220
221 return ret;
222 }
223 EXPORT_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. */
227 void 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 }
234 EXPORT_SYMBOL_GPL(vhost_poll_stop);
235
236 void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work)
237 {
238 struct vhost_flush_struct flush;
239
240 if (dev->worker) {
241 init_completion(&flush.wait_event);
242 vhost_work_init(&flush.work, vhost_flush_work);
243
244 vhost_work_queue(dev, &flush.work);
245 wait_for_completion(&flush.wait_event);
246 }
247 }
248 EXPORT_SYMBOL_GPL(vhost_work_flush);
249
250 /* Flush any work that has been scheduled. When calling this, don't hold any
251 * locks that are also used by the callback. */
252 void vhost_poll_flush(struct vhost_poll *poll)
253 {
254 vhost_work_flush(poll->dev, &poll->work);
255 }
256 EXPORT_SYMBOL_GPL(vhost_poll_flush);
257
258 void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work)
259 {
260 if (!dev->worker)
261 return;
262
263 if (!test_and_set_bit(VHOST_WORK_QUEUED, &work->flags)) {
264 /* We can only add the work to the list after we're
265 * sure it was not in the list.
266 * test_and_set_bit() implies a memory barrier.
267 */
268 llist_add(&work->node, &dev->work_list);
269 wake_up_process(dev->worker);
270 }
271 }
272 EXPORT_SYMBOL_GPL(vhost_work_queue);
273
274 /* A lockless hint for busy polling code to exit the loop */
275 bool vhost_has_work(struct vhost_dev *dev)
276 {
277 return !llist_empty(&dev->work_list);
278 }
279 EXPORT_SYMBOL_GPL(vhost_has_work);
280
281 void vhost_poll_queue(struct vhost_poll *poll)
282 {
283 vhost_work_queue(poll->dev, &poll->work);
284 }
285 EXPORT_SYMBOL_GPL(vhost_poll_queue);
286
287 static void __vhost_vq_meta_reset(struct vhost_virtqueue *vq)
288 {
289 int j;
290
291 for (j = 0; j < VHOST_NUM_ADDRS; j++)
292 vq->meta_iotlb[j] = NULL;
293 }
294
295 static void vhost_vq_meta_reset(struct vhost_dev *d)
296 {
297 int i;
298
299 for (i = 0; i < d->nvqs; ++i)
300 __vhost_vq_meta_reset(d->vqs[i]);
301 }
302
303 static void vhost_vq_reset(struct vhost_dev *dev,
304 struct vhost_virtqueue *vq)
305 {
306 vq->num = 1;
307 vq->desc = NULL;
308 vq->avail = NULL;
309 vq->used = NULL;
310 vq->last_avail_idx = 0;
311 vq->avail_idx = 0;
312 vq->last_used_idx = 0;
313 vq->signalled_used = 0;
314 vq->signalled_used_valid = false;
315 vq->used_flags = 0;
316 vq->log_used = false;
317 vq->log_addr = -1ull;
318 vq->private_data = NULL;
319 vq->acked_features = 0;
320 vq->log_base = NULL;
321 vq->error_ctx = NULL;
322 vq->error = NULL;
323 vq->kick = NULL;
324 vq->call_ctx = NULL;
325 vq->call = NULL;
326 vq->log_ctx = NULL;
327 vhost_reset_is_le(vq);
328 vhost_disable_cross_endian(vq);
329 vq->busyloop_timeout = 0;
330 vq->umem = NULL;
331 vq->iotlb = NULL;
332 __vhost_vq_meta_reset(vq);
333 }
334
335 static int vhost_worker(void *data)
336 {
337 struct vhost_dev *dev = data;
338 struct vhost_work *work, *work_next;
339 struct llist_node *node;
340 mm_segment_t oldfs = get_fs();
341
342 set_fs(USER_DS);
343 use_mm(dev->mm);
344
345 for (;;) {
346 /* mb paired w/ kthread_stop */
347 set_current_state(TASK_INTERRUPTIBLE);
348
349 if (kthread_should_stop()) {
350 __set_current_state(TASK_RUNNING);
351 break;
352 }
353
354 node = llist_del_all(&dev->work_list);
355 if (!node)
356 schedule();
357
358 node = llist_reverse_order(node);
359 /* make sure flag is seen after deletion */
360 smp_wmb();
361 llist_for_each_entry_safe(work, work_next, node, node) {
362 clear_bit(VHOST_WORK_QUEUED, &work->flags);
363 __set_current_state(TASK_RUNNING);
364 work->fn(work);
365 if (need_resched())
366 schedule();
367 }
368 }
369 unuse_mm(dev->mm);
370 set_fs(oldfs);
371 return 0;
372 }
373
374 static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq)
375 {
376 kfree(vq->indirect);
377 vq->indirect = NULL;
378 kfree(vq->log);
379 vq->log = NULL;
380 kfree(vq->heads);
381 vq->heads = NULL;
382 }
383
384 /* Helper to allocate iovec buffers for all vqs. */
385 static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
386 {
387 struct vhost_virtqueue *vq;
388 int i;
389
390 for (i = 0; i < dev->nvqs; ++i) {
391 vq = dev->vqs[i];
392 vq->indirect = kmalloc(sizeof *vq->indirect * UIO_MAXIOV,
393 GFP_KERNEL);
394 vq->log = kmalloc(sizeof *vq->log * UIO_MAXIOV, GFP_KERNEL);
395 vq->heads = kmalloc(sizeof *vq->heads * UIO_MAXIOV, GFP_KERNEL);
396 if (!vq->indirect || !vq->log || !vq->heads)
397 goto err_nomem;
398 }
399 return 0;
400
401 err_nomem:
402 for (; i >= 0; --i)
403 vhost_vq_free_iovecs(dev->vqs[i]);
404 return -ENOMEM;
405 }
406
407 static void vhost_dev_free_iovecs(struct vhost_dev *dev)
408 {
409 int i;
410
411 for (i = 0; i < dev->nvqs; ++i)
412 vhost_vq_free_iovecs(dev->vqs[i]);
413 }
414
415 void vhost_dev_init(struct vhost_dev *dev,
416 struct vhost_virtqueue **vqs, int nvqs)
417 {
418 struct vhost_virtqueue *vq;
419 int i;
420
421 dev->vqs = vqs;
422 dev->nvqs = nvqs;
423 mutex_init(&dev->mutex);
424 dev->log_ctx = NULL;
425 dev->log_file = NULL;
426 dev->umem = NULL;
427 dev->iotlb = NULL;
428 dev->mm = NULL;
429 dev->worker = NULL;
430 init_llist_head(&dev->work_list);
431 init_waitqueue_head(&dev->wait);
432 INIT_LIST_HEAD(&dev->read_list);
433 INIT_LIST_HEAD(&dev->pending_list);
434 spin_lock_init(&dev->iotlb_lock);
435
436
437 for (i = 0; i < dev->nvqs; ++i) {
438 vq = dev->vqs[i];
439 vq->log = NULL;
440 vq->indirect = NULL;
441 vq->heads = NULL;
442 vq->dev = dev;
443 mutex_init(&vq->mutex);
444 vhost_vq_reset(dev, vq);
445 if (vq->handle_kick)
446 vhost_poll_init(&vq->poll, vq->handle_kick,
447 POLLIN, dev);
448 }
449 }
450 EXPORT_SYMBOL_GPL(vhost_dev_init);
451
452 /* Caller should have device mutex */
453 long vhost_dev_check_owner(struct vhost_dev *dev)
454 {
455 /* Are you the owner? If not, I don't think you mean to do that */
456 return dev->mm == current->mm ? 0 : -EPERM;
457 }
458 EXPORT_SYMBOL_GPL(vhost_dev_check_owner);
459
460 struct vhost_attach_cgroups_struct {
461 struct vhost_work work;
462 struct task_struct *owner;
463 int ret;
464 };
465
466 static void vhost_attach_cgroups_work(struct vhost_work *work)
467 {
468 struct vhost_attach_cgroups_struct *s;
469
470 s = container_of(work, struct vhost_attach_cgroups_struct, work);
471 s->ret = cgroup_attach_task_all(s->owner, current);
472 }
473
474 static int vhost_attach_cgroups(struct vhost_dev *dev)
475 {
476 struct vhost_attach_cgroups_struct attach;
477
478 attach.owner = current;
479 vhost_work_init(&attach.work, vhost_attach_cgroups_work);
480 vhost_work_queue(dev, &attach.work);
481 vhost_work_flush(dev, &attach.work);
482 return attach.ret;
483 }
484
485 /* Caller should have device mutex */
486 bool vhost_dev_has_owner(struct vhost_dev *dev)
487 {
488 return dev->mm;
489 }
490 EXPORT_SYMBOL_GPL(vhost_dev_has_owner);
491
492 /* Caller should have device mutex */
493 long vhost_dev_set_owner(struct vhost_dev *dev)
494 {
495 struct task_struct *worker;
496 int err;
497
498 /* Is there an owner already? */
499 if (vhost_dev_has_owner(dev)) {
500 err = -EBUSY;
501 goto err_mm;
502 }
503
504 /* No owner, become one */
505 dev->mm = get_task_mm(current);
506 worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid);
507 if (IS_ERR(worker)) {
508 err = PTR_ERR(worker);
509 goto err_worker;
510 }
511
512 dev->worker = worker;
513 wake_up_process(worker); /* avoid contributing to loadavg */
514
515 err = vhost_attach_cgroups(dev);
516 if (err)
517 goto err_cgroup;
518
519 err = vhost_dev_alloc_iovecs(dev);
520 if (err)
521 goto err_cgroup;
522
523 return 0;
524 err_cgroup:
525 kthread_stop(worker);
526 dev->worker = NULL;
527 err_worker:
528 if (dev->mm)
529 mmput(dev->mm);
530 dev->mm = NULL;
531 err_mm:
532 return err;
533 }
534 EXPORT_SYMBOL_GPL(vhost_dev_set_owner);
535
536 struct vhost_umem *vhost_dev_reset_owner_prepare(void)
537 {
538 return kvzalloc(sizeof(struct vhost_umem), GFP_KERNEL);
539 }
540 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare);
541
542 /* Caller should have device mutex */
543 void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_umem *umem)
544 {
545 int i;
546
547 vhost_dev_cleanup(dev, true);
548
549 /* Restore memory to default empty mapping. */
550 INIT_LIST_HEAD(&umem->umem_list);
551 dev->umem = umem;
552 /* We don't need VQ locks below since vhost_dev_cleanup makes sure
553 * VQs aren't running.
554 */
555 for (i = 0; i < dev->nvqs; ++i)
556 dev->vqs[i]->umem = umem;
557 }
558 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner);
559
560 void vhost_dev_stop(struct vhost_dev *dev)
561 {
562 int i;
563
564 for (i = 0; i < dev->nvqs; ++i) {
565 if (dev->vqs[i]->kick && dev->vqs[i]->handle_kick) {
566 vhost_poll_stop(&dev->vqs[i]->poll);
567 vhost_poll_flush(&dev->vqs[i]->poll);
568 }
569 }
570 }
571 EXPORT_SYMBOL_GPL(vhost_dev_stop);
572
573 static void vhost_umem_free(struct vhost_umem *umem,
574 struct vhost_umem_node *node)
575 {
576 vhost_umem_interval_tree_remove(node, &umem->umem_tree);
577 list_del(&node->link);
578 kfree(node);
579 umem->numem--;
580 }
581
582 static void vhost_umem_clean(struct vhost_umem *umem)
583 {
584 struct vhost_umem_node *node, *tmp;
585
586 if (!umem)
587 return;
588
589 list_for_each_entry_safe(node, tmp, &umem->umem_list, link)
590 vhost_umem_free(umem, node);
591
592 kvfree(umem);
593 }
594
595 static void vhost_clear_msg(struct vhost_dev *dev)
596 {
597 struct vhost_msg_node *node, *n;
598
599 spin_lock(&dev->iotlb_lock);
600
601 list_for_each_entry_safe(node, n, &dev->read_list, node) {
602 list_del(&node->node);
603 kfree(node);
604 }
605
606 list_for_each_entry_safe(node, n, &dev->pending_list, node) {
607 list_del(&node->node);
608 kfree(node);
609 }
610
611 spin_unlock(&dev->iotlb_lock);
612 }
613
614 /* Caller should have device mutex if and only if locked is set */
615 void vhost_dev_cleanup(struct vhost_dev *dev, bool locked)
616 {
617 int i;
618
619 for (i = 0; i < dev->nvqs; ++i) {
620 if (dev->vqs[i]->error_ctx)
621 eventfd_ctx_put(dev->vqs[i]->error_ctx);
622 if (dev->vqs[i]->error)
623 fput(dev->vqs[i]->error);
624 if (dev->vqs[i]->kick)
625 fput(dev->vqs[i]->kick);
626 if (dev->vqs[i]->call_ctx)
627 eventfd_ctx_put(dev->vqs[i]->call_ctx);
628 if (dev->vqs[i]->call)
629 fput(dev->vqs[i]->call);
630 vhost_vq_reset(dev, dev->vqs[i]);
631 }
632 vhost_dev_free_iovecs(dev);
633 if (dev->log_ctx)
634 eventfd_ctx_put(dev->log_ctx);
635 dev->log_ctx = NULL;
636 if (dev->log_file)
637 fput(dev->log_file);
638 dev->log_file = NULL;
639 /* No one will access memory at this point */
640 vhost_umem_clean(dev->umem);
641 dev->umem = NULL;
642 vhost_umem_clean(dev->iotlb);
643 dev->iotlb = NULL;
644 vhost_clear_msg(dev);
645 wake_up_interruptible_poll(&dev->wait, POLLIN | POLLRDNORM);
646 WARN_ON(!llist_empty(&dev->work_list));
647 if (dev->worker) {
648 kthread_stop(dev->worker);
649 dev->worker = NULL;
650 }
651 if (dev->mm)
652 mmput(dev->mm);
653 dev->mm = NULL;
654 }
655 EXPORT_SYMBOL_GPL(vhost_dev_cleanup);
656
657 static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
658 {
659 u64 a = addr / VHOST_PAGE_SIZE / 8;
660
661 /* Make sure 64 bit math will not overflow. */
662 if (a > ULONG_MAX - (unsigned long)log_base ||
663 a + (unsigned long)log_base > ULONG_MAX)
664 return 0;
665
666 return access_ok(VERIFY_WRITE, log_base + a,
667 (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8);
668 }
669
670 static bool vhost_overflow(u64 uaddr, u64 size)
671 {
672 /* Make sure 64 bit math will not overflow. */
673 return uaddr > ULONG_MAX || size > ULONG_MAX || uaddr > ULONG_MAX - size;
674 }
675
676 /* Caller should have vq mutex and device mutex. */
677 static int vq_memory_access_ok(void __user *log_base, struct vhost_umem *umem,
678 int log_all)
679 {
680 struct vhost_umem_node *node;
681
682 if (!umem)
683 return 0;
684
685 list_for_each_entry(node, &umem->umem_list, link) {
686 unsigned long a = node->userspace_addr;
687
688 if (vhost_overflow(node->userspace_addr, node->size))
689 return 0;
690
691
692 if (!access_ok(VERIFY_WRITE, (void __user *)a,
693 node->size))
694 return 0;
695 else if (log_all && !log_access_ok(log_base,
696 node->start,
697 node->size))
698 return 0;
699 }
700 return 1;
701 }
702
703 static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq,
704 u64 addr, unsigned int size,
705 int type)
706 {
707 const struct vhost_umem_node *node = vq->meta_iotlb[type];
708
709 if (!node)
710 return NULL;
711
712 return (void *)(uintptr_t)(node->userspace_addr + addr - node->start);
713 }
714
715 /* Can we switch to this memory table? */
716 /* Caller should have device mutex but not vq mutex */
717 static int memory_access_ok(struct vhost_dev *d, struct vhost_umem *umem,
718 int log_all)
719 {
720 int i;
721
722 for (i = 0; i < d->nvqs; ++i) {
723 int ok;
724 bool log;
725
726 mutex_lock(&d->vqs[i]->mutex);
727 log = log_all || vhost_has_feature(d->vqs[i], VHOST_F_LOG_ALL);
728 /* If ring is inactive, will check when it's enabled. */
729 if (d->vqs[i]->private_data)
730 ok = vq_memory_access_ok(d->vqs[i]->log_base,
731 umem, log);
732 else
733 ok = 1;
734 mutex_unlock(&d->vqs[i]->mutex);
735 if (!ok)
736 return 0;
737 }
738 return 1;
739 }
740
741 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
742 struct iovec iov[], int iov_size, int access);
743
744 static int vhost_copy_to_user(struct vhost_virtqueue *vq, void __user *to,
745 const void *from, unsigned size)
746 {
747 int ret;
748
749 if (!vq->iotlb)
750 return __copy_to_user(to, from, size);
751 else {
752 /* This function should be called after iotlb
753 * prefetch, which means we're sure that all vq
754 * could be access through iotlb. So -EAGAIN should
755 * not happen in this case.
756 */
757 struct iov_iter t;
758 void __user *uaddr = vhost_vq_meta_fetch(vq,
759 (u64)(uintptr_t)to, size,
760 VHOST_ADDR_USED);
761
762 if (uaddr)
763 return __copy_to_user(uaddr, from, size);
764
765 ret = translate_desc(vq, (u64)(uintptr_t)to, size, vq->iotlb_iov,
766 ARRAY_SIZE(vq->iotlb_iov),
767 VHOST_ACCESS_WO);
768 if (ret < 0)
769 goto out;
770 iov_iter_init(&t, WRITE, vq->iotlb_iov, ret, size);
771 ret = copy_to_iter(from, size, &t);
772 if (ret == size)
773 ret = 0;
774 }
775 out:
776 return ret;
777 }
778
779 static int vhost_copy_from_user(struct vhost_virtqueue *vq, void *to,
780 void __user *from, unsigned size)
781 {
782 int ret;
783
784 if (!vq->iotlb)
785 return __copy_from_user(to, from, size);
786 else {
787 /* This function should be called after iotlb
788 * prefetch, which means we're sure that vq
789 * could be access through iotlb. So -EAGAIN should
790 * not happen in this case.
791 */
792 void __user *uaddr = vhost_vq_meta_fetch(vq,
793 (u64)(uintptr_t)from, size,
794 VHOST_ADDR_DESC);
795 struct iov_iter f;
796
797 if (uaddr)
798 return __copy_from_user(to, uaddr, size);
799
800 ret = translate_desc(vq, (u64)(uintptr_t)from, size, vq->iotlb_iov,
801 ARRAY_SIZE(vq->iotlb_iov),
802 VHOST_ACCESS_RO);
803 if (ret < 0) {
804 vq_err(vq, "IOTLB translation failure: uaddr "
805 "%p size 0x%llx\n", from,
806 (unsigned long long) size);
807 goto out;
808 }
809 iov_iter_init(&f, READ, vq->iotlb_iov, ret, size);
810 ret = copy_from_iter(to, size, &f);
811 if (ret == size)
812 ret = 0;
813 }
814
815 out:
816 return ret;
817 }
818
819 static void __user *__vhost_get_user_slow(struct vhost_virtqueue *vq,
820 void __user *addr, unsigned int size,
821 int type)
822 {
823 int ret;
824
825 ret = translate_desc(vq, (u64)(uintptr_t)addr, size, vq->iotlb_iov,
826 ARRAY_SIZE(vq->iotlb_iov),
827 VHOST_ACCESS_RO);
828 if (ret < 0) {
829 vq_err(vq, "IOTLB translation failure: uaddr "
830 "%p size 0x%llx\n", addr,
831 (unsigned long long) size);
832 return NULL;
833 }
834
835 if (ret != 1 || vq->iotlb_iov[0].iov_len != size) {
836 vq_err(vq, "Non atomic userspace memory access: uaddr "
837 "%p size 0x%llx\n", addr,
838 (unsigned long long) size);
839 return NULL;
840 }
841
842 return vq->iotlb_iov[0].iov_base;
843 }
844
845 /* This function should be called after iotlb
846 * prefetch, which means we're sure that vq
847 * could be access through iotlb. So -EAGAIN should
848 * not happen in this case.
849 */
850 static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq,
851 void *addr, unsigned int size,
852 int type)
853 {
854 void __user *uaddr = vhost_vq_meta_fetch(vq,
855 (u64)(uintptr_t)addr, size, type);
856 if (uaddr)
857 return uaddr;
858
859 return __vhost_get_user_slow(vq, addr, size, type);
860 }
861
862 #define vhost_put_user(vq, x, ptr) \
863 ({ \
864 int ret = -EFAULT; \
865 if (!vq->iotlb) { \
866 ret = __put_user(x, ptr); \
867 } else { \
868 __typeof__(ptr) to = \
869 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
870 sizeof(*ptr), VHOST_ADDR_USED); \
871 if (to != NULL) \
872 ret = __put_user(x, to); \
873 else \
874 ret = -EFAULT; \
875 } \
876 ret; \
877 })
878
879 #define vhost_get_user(vq, x, ptr, type) \
880 ({ \
881 int ret; \
882 if (!vq->iotlb) { \
883 ret = __get_user(x, ptr); \
884 } else { \
885 __typeof__(ptr) from = \
886 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
887 sizeof(*ptr), \
888 type); \
889 if (from != NULL) \
890 ret = __get_user(x, from); \
891 else \
892 ret = -EFAULT; \
893 } \
894 ret; \
895 })
896
897 #define vhost_get_avail(vq, x, ptr) \
898 vhost_get_user(vq, x, ptr, VHOST_ADDR_AVAIL)
899
900 #define vhost_get_used(vq, x, ptr) \
901 vhost_get_user(vq, x, ptr, VHOST_ADDR_USED)
902
903 static void vhost_dev_lock_vqs(struct vhost_dev *d)
904 {
905 int i = 0;
906 for (i = 0; i < d->nvqs; ++i)
907 mutex_lock_nested(&d->vqs[i]->mutex, i);
908 }
909
910 static void vhost_dev_unlock_vqs(struct vhost_dev *d)
911 {
912 int i = 0;
913 for (i = 0; i < d->nvqs; ++i)
914 mutex_unlock(&d->vqs[i]->mutex);
915 }
916
917 static int vhost_new_umem_range(struct vhost_umem *umem,
918 u64 start, u64 size, u64 end,
919 u64 userspace_addr, int perm)
920 {
921 struct vhost_umem_node *tmp, *node = kmalloc(sizeof(*node), GFP_ATOMIC);
922
923 if (!node)
924 return -ENOMEM;
925
926 if (umem->numem == max_iotlb_entries) {
927 tmp = list_first_entry(&umem->umem_list, typeof(*tmp), link);
928 vhost_umem_free(umem, tmp);
929 }
930
931 node->start = start;
932 node->size = size;
933 node->last = end;
934 node->userspace_addr = userspace_addr;
935 node->perm = perm;
936 INIT_LIST_HEAD(&node->link);
937 list_add_tail(&node->link, &umem->umem_list);
938 vhost_umem_interval_tree_insert(node, &umem->umem_tree);
939 umem->numem++;
940
941 return 0;
942 }
943
944 static void vhost_del_umem_range(struct vhost_umem *umem,
945 u64 start, u64 end)
946 {
947 struct vhost_umem_node *node;
948
949 while ((node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
950 start, end)))
951 vhost_umem_free(umem, node);
952 }
953
954 static void vhost_iotlb_notify_vq(struct vhost_dev *d,
955 struct vhost_iotlb_msg *msg)
956 {
957 struct vhost_msg_node *node, *n;
958
959 spin_lock(&d->iotlb_lock);
960
961 list_for_each_entry_safe(node, n, &d->pending_list, node) {
962 struct vhost_iotlb_msg *vq_msg = &node->msg.iotlb;
963 if (msg->iova <= vq_msg->iova &&
964 msg->iova + msg->size - 1 > vq_msg->iova &&
965 vq_msg->type == VHOST_IOTLB_MISS) {
966 vhost_poll_queue(&node->vq->poll);
967 list_del(&node->node);
968 kfree(node);
969 }
970 }
971
972 spin_unlock(&d->iotlb_lock);
973 }
974
975 static int umem_access_ok(u64 uaddr, u64 size, int access)
976 {
977 unsigned long a = uaddr;
978
979 /* Make sure 64 bit math will not overflow. */
980 if (vhost_overflow(uaddr, size))
981 return -EFAULT;
982
983 if ((access & VHOST_ACCESS_RO) &&
984 !access_ok(VERIFY_READ, (void __user *)a, size))
985 return -EFAULT;
986 if ((access & VHOST_ACCESS_WO) &&
987 !access_ok(VERIFY_WRITE, (void __user *)a, size))
988 return -EFAULT;
989 return 0;
990 }
991
992 static int vhost_process_iotlb_msg(struct vhost_dev *dev,
993 struct vhost_iotlb_msg *msg)
994 {
995 int ret = 0;
996
997 mutex_lock(&dev->mutex);
998 vhost_dev_lock_vqs(dev);
999 switch (msg->type) {
1000 case VHOST_IOTLB_UPDATE:
1001 if (!dev->iotlb) {
1002 ret = -EFAULT;
1003 break;
1004 }
1005 if (umem_access_ok(msg->uaddr, msg->size, msg->perm)) {
1006 ret = -EFAULT;
1007 break;
1008 }
1009 vhost_vq_meta_reset(dev);
1010 if (vhost_new_umem_range(dev->iotlb, msg->iova, msg->size,
1011 msg->iova + msg->size - 1,
1012 msg->uaddr, msg->perm)) {
1013 ret = -ENOMEM;
1014 break;
1015 }
1016 vhost_iotlb_notify_vq(dev, msg);
1017 break;
1018 case VHOST_IOTLB_INVALIDATE:
1019 if (!dev->iotlb) {
1020 ret = -EFAULT;
1021 break;
1022 }
1023 vhost_vq_meta_reset(dev);
1024 vhost_del_umem_range(dev->iotlb, msg->iova,
1025 msg->iova + msg->size - 1);
1026 break;
1027 default:
1028 ret = -EINVAL;
1029 break;
1030 }
1031
1032 vhost_dev_unlock_vqs(dev);
1033 mutex_unlock(&dev->mutex);
1034
1035 return ret;
1036 }
1037 ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
1038 struct iov_iter *from)
1039 {
1040 struct vhost_msg_node node;
1041 unsigned size = sizeof(struct vhost_msg);
1042 size_t ret;
1043 int err;
1044
1045 if (iov_iter_count(from) < size)
1046 return 0;
1047 ret = copy_from_iter(&node.msg, size, from);
1048 if (ret != size)
1049 goto done;
1050
1051 switch (node.msg.type) {
1052 case VHOST_IOTLB_MSG:
1053 err = vhost_process_iotlb_msg(dev, &node.msg.iotlb);
1054 if (err)
1055 ret = err;
1056 break;
1057 default:
1058 ret = -EINVAL;
1059 break;
1060 }
1061
1062 done:
1063 return ret;
1064 }
1065 EXPORT_SYMBOL(vhost_chr_write_iter);
1066
1067 unsigned int vhost_chr_poll(struct file *file, struct vhost_dev *dev,
1068 poll_table *wait)
1069 {
1070 unsigned int mask = 0;
1071
1072 poll_wait(file, &dev->wait, wait);
1073
1074 if (!list_empty(&dev->read_list))
1075 mask |= POLLIN | POLLRDNORM;
1076
1077 return mask;
1078 }
1079 EXPORT_SYMBOL(vhost_chr_poll);
1080
1081 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
1082 int noblock)
1083 {
1084 DEFINE_WAIT(wait);
1085 struct vhost_msg_node *node;
1086 ssize_t ret = 0;
1087 unsigned size = sizeof(struct vhost_msg);
1088
1089 if (iov_iter_count(to) < size)
1090 return 0;
1091
1092 while (1) {
1093 if (!noblock)
1094 prepare_to_wait(&dev->wait, &wait,
1095 TASK_INTERRUPTIBLE);
1096
1097 node = vhost_dequeue_msg(dev, &dev->read_list);
1098 if (node)
1099 break;
1100 if (noblock) {
1101 ret = -EAGAIN;
1102 break;
1103 }
1104 if (signal_pending(current)) {
1105 ret = -ERESTARTSYS;
1106 break;
1107 }
1108 if (!dev->iotlb) {
1109 ret = -EBADFD;
1110 break;
1111 }
1112
1113 schedule();
1114 }
1115
1116 if (!noblock)
1117 finish_wait(&dev->wait, &wait);
1118
1119 if (node) {
1120 ret = copy_to_iter(&node->msg, size, to);
1121
1122 if (ret != size || node->msg.type != VHOST_IOTLB_MISS) {
1123 kfree(node);
1124 return ret;
1125 }
1126
1127 vhost_enqueue_msg(dev, &dev->pending_list, node);
1128 }
1129
1130 return ret;
1131 }
1132 EXPORT_SYMBOL_GPL(vhost_chr_read_iter);
1133
1134 static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access)
1135 {
1136 struct vhost_dev *dev = vq->dev;
1137 struct vhost_msg_node *node;
1138 struct vhost_iotlb_msg *msg;
1139
1140 node = vhost_new_msg(vq, VHOST_IOTLB_MISS);
1141 if (!node)
1142 return -ENOMEM;
1143
1144 msg = &node->msg.iotlb;
1145 msg->type = VHOST_IOTLB_MISS;
1146 msg->iova = iova;
1147 msg->perm = access;
1148
1149 vhost_enqueue_msg(dev, &dev->read_list, node);
1150
1151 return 0;
1152 }
1153
1154 static int vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
1155 struct vring_desc __user *desc,
1156 struct vring_avail __user *avail,
1157 struct vring_used __user *used)
1158
1159 {
1160 size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
1161
1162 return access_ok(VERIFY_READ, desc, num * sizeof *desc) &&
1163 access_ok(VERIFY_READ, avail,
1164 sizeof *avail + num * sizeof *avail->ring + s) &&
1165 access_ok(VERIFY_WRITE, used,
1166 sizeof *used + num * sizeof *used->ring + s);
1167 }
1168
1169 static void vhost_vq_meta_update(struct vhost_virtqueue *vq,
1170 const struct vhost_umem_node *node,
1171 int type)
1172 {
1173 int access = (type == VHOST_ADDR_USED) ?
1174 VHOST_ACCESS_WO : VHOST_ACCESS_RO;
1175
1176 if (likely(node->perm & access))
1177 vq->meta_iotlb[type] = node;
1178 }
1179
1180 static int iotlb_access_ok(struct vhost_virtqueue *vq,
1181 int access, u64 addr, u64 len, int type)
1182 {
1183 const struct vhost_umem_node *node;
1184 struct vhost_umem *umem = vq->iotlb;
1185 u64 s = 0, size, orig_addr = addr, last = addr + len - 1;
1186
1187 if (vhost_vq_meta_fetch(vq, addr, len, type))
1188 return true;
1189
1190 while (len > s) {
1191 node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
1192 addr,
1193 last);
1194 if (node == NULL || node->start > addr) {
1195 vhost_iotlb_miss(vq, addr, access);
1196 return false;
1197 } else if (!(node->perm & access)) {
1198 /* Report the possible access violation by
1199 * request another translation from userspace.
1200 */
1201 return false;
1202 }
1203
1204 size = node->size - addr + node->start;
1205
1206 if (orig_addr == addr && size >= len)
1207 vhost_vq_meta_update(vq, node, type);
1208
1209 s += size;
1210 addr += size;
1211 }
1212
1213 return true;
1214 }
1215
1216 int vq_iotlb_prefetch(struct vhost_virtqueue *vq)
1217 {
1218 size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
1219 unsigned int num = vq->num;
1220
1221 if (!vq->iotlb)
1222 return 1;
1223
1224 return iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->desc,
1225 num * sizeof(*vq->desc), VHOST_ADDR_DESC) &&
1226 iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->avail,
1227 sizeof *vq->avail +
1228 num * sizeof(*vq->avail->ring) + s,
1229 VHOST_ADDR_AVAIL) &&
1230 iotlb_access_ok(vq, VHOST_ACCESS_WO, (u64)(uintptr_t)vq->used,
1231 sizeof *vq->used +
1232 num * sizeof(*vq->used->ring) + s,
1233 VHOST_ADDR_USED);
1234 }
1235 EXPORT_SYMBOL_GPL(vq_iotlb_prefetch);
1236
1237 /* Can we log writes? */
1238 /* Caller should have device mutex but not vq mutex */
1239 int vhost_log_access_ok(struct vhost_dev *dev)
1240 {
1241 return memory_access_ok(dev, dev->umem, 1);
1242 }
1243 EXPORT_SYMBOL_GPL(vhost_log_access_ok);
1244
1245 /* Verify access for write logging. */
1246 /* Caller should have vq mutex and device mutex */
1247 static int vq_log_access_ok(struct vhost_virtqueue *vq,
1248 void __user *log_base)
1249 {
1250 size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
1251
1252 return vq_memory_access_ok(log_base, vq->umem,
1253 vhost_has_feature(vq, VHOST_F_LOG_ALL)) &&
1254 (!vq->log_used || log_access_ok(log_base, vq->log_addr,
1255 sizeof *vq->used +
1256 vq->num * sizeof *vq->used->ring + s));
1257 }
1258
1259 /* Can we start vq? */
1260 /* Caller should have vq mutex and device mutex */
1261 int vhost_vq_access_ok(struct vhost_virtqueue *vq)
1262 {
1263 if (!vq_log_access_ok(vq, vq->log_base))
1264 return 0;
1265
1266 /* Access validation occurs at prefetch time with IOTLB */
1267 if (vq->iotlb)
1268 return 1;
1269
1270 return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used);
1271 }
1272 EXPORT_SYMBOL_GPL(vhost_vq_access_ok);
1273
1274 static struct vhost_umem *vhost_umem_alloc(void)
1275 {
1276 struct vhost_umem *umem = kvzalloc(sizeof(*umem), GFP_KERNEL);
1277
1278 if (!umem)
1279 return NULL;
1280
1281 umem->umem_tree = RB_ROOT_CACHED;
1282 umem->numem = 0;
1283 INIT_LIST_HEAD(&umem->umem_list);
1284
1285 return umem;
1286 }
1287
1288 static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
1289 {
1290 struct vhost_memory mem, *newmem;
1291 struct vhost_memory_region *region;
1292 struct vhost_umem *newumem, *oldumem;
1293 unsigned long size = offsetof(struct vhost_memory, regions);
1294 int i;
1295
1296 if (copy_from_user(&mem, m, size))
1297 return -EFAULT;
1298 if (mem.padding)
1299 return -EOPNOTSUPP;
1300 if (mem.nregions > max_mem_regions)
1301 return -E2BIG;
1302 newmem = kvzalloc(size + mem.nregions * sizeof(*m->regions), GFP_KERNEL);
1303 if (!newmem)
1304 return -ENOMEM;
1305
1306 memcpy(newmem, &mem, size);
1307 if (copy_from_user(newmem->regions, m->regions,
1308 mem.nregions * sizeof *m->regions)) {
1309 kvfree(newmem);
1310 return -EFAULT;
1311 }
1312
1313 newumem = vhost_umem_alloc();
1314 if (!newumem) {
1315 kvfree(newmem);
1316 return -ENOMEM;
1317 }
1318
1319 for (region = newmem->regions;
1320 region < newmem->regions + mem.nregions;
1321 region++) {
1322 if (vhost_new_umem_range(newumem,
1323 region->guest_phys_addr,
1324 region->memory_size,
1325 region->guest_phys_addr +
1326 region->memory_size - 1,
1327 region->userspace_addr,
1328 VHOST_ACCESS_RW))
1329 goto err;
1330 }
1331
1332 if (!memory_access_ok(d, newumem, 0))
1333 goto err;
1334
1335 oldumem = d->umem;
1336 d->umem = newumem;
1337
1338 /* All memory accesses are done under some VQ mutex. */
1339 for (i = 0; i < d->nvqs; ++i) {
1340 mutex_lock(&d->vqs[i]->mutex);
1341 d->vqs[i]->umem = newumem;
1342 mutex_unlock(&d->vqs[i]->mutex);
1343 }
1344
1345 kvfree(newmem);
1346 vhost_umem_clean(oldumem);
1347 return 0;
1348
1349 err:
1350 vhost_umem_clean(newumem);
1351 kvfree(newmem);
1352 return -EFAULT;
1353 }
1354
1355 long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp)
1356 {
1357 struct file *eventfp, *filep = NULL;
1358 bool pollstart = false, pollstop = false;
1359 struct eventfd_ctx *ctx = NULL;
1360 u32 __user *idxp = argp;
1361 struct vhost_virtqueue *vq;
1362 struct vhost_vring_state s;
1363 struct vhost_vring_file f;
1364 struct vhost_vring_addr a;
1365 u32 idx;
1366 long r;
1367
1368 r = get_user(idx, idxp);
1369 if (r < 0)
1370 return r;
1371 if (idx >= d->nvqs)
1372 return -ENOBUFS;
1373
1374 idx = array_index_nospec(idx, d->nvqs);
1375 vq = d->vqs[idx];
1376
1377 mutex_lock(&vq->mutex);
1378
1379 switch (ioctl) {
1380 case VHOST_SET_VRING_NUM:
1381 /* Resizing ring with an active backend?
1382 * You don't want to do that. */
1383 if (vq->private_data) {
1384 r = -EBUSY;
1385 break;
1386 }
1387 if (copy_from_user(&s, argp, sizeof s)) {
1388 r = -EFAULT;
1389 break;
1390 }
1391 if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) {
1392 r = -EINVAL;
1393 break;
1394 }
1395 vq->num = s.num;
1396 break;
1397 case VHOST_SET_VRING_BASE:
1398 /* Moving base with an active backend?
1399 * You don't want to do that. */
1400 if (vq->private_data) {
1401 r = -EBUSY;
1402 break;
1403 }
1404 if (copy_from_user(&s, argp, sizeof s)) {
1405 r = -EFAULT;
1406 break;
1407 }
1408 if (s.num > 0xffff) {
1409 r = -EINVAL;
1410 break;
1411 }
1412 vq->last_avail_idx = s.num;
1413 /* Forget the cached index value. */
1414 vq->avail_idx = vq->last_avail_idx;
1415 break;
1416 case VHOST_GET_VRING_BASE:
1417 s.index = idx;
1418 s.num = vq->last_avail_idx;
1419 if (copy_to_user(argp, &s, sizeof s))
1420 r = -EFAULT;
1421 break;
1422 case VHOST_SET_VRING_ADDR:
1423 if (copy_from_user(&a, argp, sizeof a)) {
1424 r = -EFAULT;
1425 break;
1426 }
1427 if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) {
1428 r = -EOPNOTSUPP;
1429 break;
1430 }
1431 /* For 32bit, verify that the top 32bits of the user
1432 data are set to zero. */
1433 if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr ||
1434 (u64)(unsigned long)a.used_user_addr != a.used_user_addr ||
1435 (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) {
1436 r = -EFAULT;
1437 break;
1438 }
1439
1440 /* Make sure it's safe to cast pointers to vring types. */
1441 BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE);
1442 BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE);
1443 if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) ||
1444 (a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) ||
1445 (a.log_guest_addr & (VRING_USED_ALIGN_SIZE - 1))) {
1446 r = -EINVAL;
1447 break;
1448 }
1449
1450 /* We only verify access here if backend is configured.
1451 * If it is not, we don't as size might not have been setup.
1452 * We will verify when backend is configured. */
1453 if (vq->private_data) {
1454 if (!vq_access_ok(vq, vq->num,
1455 (void __user *)(unsigned long)a.desc_user_addr,
1456 (void __user *)(unsigned long)a.avail_user_addr,
1457 (void __user *)(unsigned long)a.used_user_addr)) {
1458 r = -EINVAL;
1459 break;
1460 }
1461
1462 /* Also validate log access for used ring if enabled. */
1463 if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) &&
1464 !log_access_ok(vq->log_base, a.log_guest_addr,
1465 sizeof *vq->used +
1466 vq->num * sizeof *vq->used->ring)) {
1467 r = -EINVAL;
1468 break;
1469 }
1470 }
1471
1472 vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG));
1473 vq->desc = (void __user *)(unsigned long)a.desc_user_addr;
1474 vq->avail = (void __user *)(unsigned long)a.avail_user_addr;
1475 vq->log_addr = a.log_guest_addr;
1476 vq->used = (void __user *)(unsigned long)a.used_user_addr;
1477 break;
1478 case VHOST_SET_VRING_KICK:
1479 if (copy_from_user(&f, argp, sizeof f)) {
1480 r = -EFAULT;
1481 break;
1482 }
1483 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
1484 if (IS_ERR(eventfp)) {
1485 r = PTR_ERR(eventfp);
1486 break;
1487 }
1488 if (eventfp != vq->kick) {
1489 pollstop = (filep = vq->kick) != NULL;
1490 pollstart = (vq->kick = eventfp) != NULL;
1491 } else
1492 filep = eventfp;
1493 break;
1494 case VHOST_SET_VRING_CALL:
1495 if (copy_from_user(&f, argp, sizeof f)) {
1496 r = -EFAULT;
1497 break;
1498 }
1499 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
1500 if (IS_ERR(eventfp)) {
1501 r = PTR_ERR(eventfp);
1502 break;
1503 }
1504 if (eventfp != vq->call) {
1505 filep = vq->call;
1506 ctx = vq->call_ctx;
1507 vq->call = eventfp;
1508 vq->call_ctx = eventfp ?
1509 eventfd_ctx_fileget(eventfp) : NULL;
1510 } else
1511 filep = eventfp;
1512 break;
1513 case VHOST_SET_VRING_ERR:
1514 if (copy_from_user(&f, argp, sizeof f)) {
1515 r = -EFAULT;
1516 break;
1517 }
1518 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
1519 if (IS_ERR(eventfp)) {
1520 r = PTR_ERR(eventfp);
1521 break;
1522 }
1523 if (eventfp != vq->error) {
1524 filep = vq->error;
1525 vq->error = eventfp;
1526 ctx = vq->error_ctx;
1527 vq->error_ctx = eventfp ?
1528 eventfd_ctx_fileget(eventfp) : NULL;
1529 } else
1530 filep = eventfp;
1531 break;
1532 case VHOST_SET_VRING_ENDIAN:
1533 r = vhost_set_vring_endian(vq, argp);
1534 break;
1535 case VHOST_GET_VRING_ENDIAN:
1536 r = vhost_get_vring_endian(vq, idx, argp);
1537 break;
1538 case VHOST_SET_VRING_BUSYLOOP_TIMEOUT:
1539 if (copy_from_user(&s, argp, sizeof(s))) {
1540 r = -EFAULT;
1541 break;
1542 }
1543 vq->busyloop_timeout = s.num;
1544 break;
1545 case VHOST_GET_VRING_BUSYLOOP_TIMEOUT:
1546 s.index = idx;
1547 s.num = vq->busyloop_timeout;
1548 if (copy_to_user(argp, &s, sizeof(s)))
1549 r = -EFAULT;
1550 break;
1551 default:
1552 r = -ENOIOCTLCMD;
1553 }
1554
1555 if (pollstop && vq->handle_kick)
1556 vhost_poll_stop(&vq->poll);
1557
1558 if (ctx)
1559 eventfd_ctx_put(ctx);
1560 if (filep)
1561 fput(filep);
1562
1563 if (pollstart && vq->handle_kick)
1564 r = vhost_poll_start(&vq->poll, vq->kick);
1565
1566 mutex_unlock(&vq->mutex);
1567
1568 if (pollstop && vq->handle_kick)
1569 vhost_poll_flush(&vq->poll);
1570 return r;
1571 }
1572 EXPORT_SYMBOL_GPL(vhost_vring_ioctl);
1573
1574 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled)
1575 {
1576 struct vhost_umem *niotlb, *oiotlb;
1577 int i;
1578
1579 niotlb = vhost_umem_alloc();
1580 if (!niotlb)
1581 return -ENOMEM;
1582
1583 oiotlb = d->iotlb;
1584 d->iotlb = niotlb;
1585
1586 for (i = 0; i < d->nvqs; ++i) {
1587 mutex_lock(&d->vqs[i]->mutex);
1588 d->vqs[i]->iotlb = niotlb;
1589 mutex_unlock(&d->vqs[i]->mutex);
1590 }
1591
1592 vhost_umem_clean(oiotlb);
1593
1594 return 0;
1595 }
1596 EXPORT_SYMBOL_GPL(vhost_init_device_iotlb);
1597
1598 /* Caller must have device mutex */
1599 long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
1600 {
1601 struct file *eventfp, *filep = NULL;
1602 struct eventfd_ctx *ctx = NULL;
1603 u64 p;
1604 long r;
1605 int i, fd;
1606
1607 /* If you are not the owner, you can become one */
1608 if (ioctl == VHOST_SET_OWNER) {
1609 r = vhost_dev_set_owner(d);
1610 goto done;
1611 }
1612
1613 /* You must be the owner to do anything else */
1614 r = vhost_dev_check_owner(d);
1615 if (r)
1616 goto done;
1617
1618 switch (ioctl) {
1619 case VHOST_SET_MEM_TABLE:
1620 r = vhost_set_memory(d, argp);
1621 break;
1622 case VHOST_SET_LOG_BASE:
1623 if (copy_from_user(&p, argp, sizeof p)) {
1624 r = -EFAULT;
1625 break;
1626 }
1627 if ((u64)(unsigned long)p != p) {
1628 r = -EFAULT;
1629 break;
1630 }
1631 for (i = 0; i < d->nvqs; ++i) {
1632 struct vhost_virtqueue *vq;
1633 void __user *base = (void __user *)(unsigned long)p;
1634 vq = d->vqs[i];
1635 mutex_lock(&vq->mutex);
1636 /* If ring is inactive, will check when it's enabled. */
1637 if (vq->private_data && !vq_log_access_ok(vq, base))
1638 r = -EFAULT;
1639 else
1640 vq->log_base = base;
1641 mutex_unlock(&vq->mutex);
1642 }
1643 break;
1644 case VHOST_SET_LOG_FD:
1645 r = get_user(fd, (int __user *)argp);
1646 if (r < 0)
1647 break;
1648 eventfp = fd == -1 ? NULL : eventfd_fget(fd);
1649 if (IS_ERR(eventfp)) {
1650 r = PTR_ERR(eventfp);
1651 break;
1652 }
1653 if (eventfp != d->log_file) {
1654 filep = d->log_file;
1655 d->log_file = eventfp;
1656 ctx = d->log_ctx;
1657 d->log_ctx = eventfp ?
1658 eventfd_ctx_fileget(eventfp) : NULL;
1659 } else
1660 filep = eventfp;
1661 for (i = 0; i < d->nvqs; ++i) {
1662 mutex_lock(&d->vqs[i]->mutex);
1663 d->vqs[i]->log_ctx = d->log_ctx;
1664 mutex_unlock(&d->vqs[i]->mutex);
1665 }
1666 if (ctx)
1667 eventfd_ctx_put(ctx);
1668 if (filep)
1669 fput(filep);
1670 break;
1671 default:
1672 r = -ENOIOCTLCMD;
1673 break;
1674 }
1675 done:
1676 return r;
1677 }
1678 EXPORT_SYMBOL_GPL(vhost_dev_ioctl);
1679
1680 /* TODO: This is really inefficient. We need something like get_user()
1681 * (instruction directly accesses the data, with an exception table entry
1682 * returning -EFAULT). See Documentation/x86/exception-tables.txt.
1683 */
1684 static int set_bit_to_user(int nr, void __user *addr)
1685 {
1686 unsigned long log = (unsigned long)addr;
1687 struct page *page;
1688 void *base;
1689 int bit = nr + (log % PAGE_SIZE) * 8;
1690 int r;
1691
1692 r = get_user_pages_fast(log, 1, 1, &page);
1693 if (r < 0)
1694 return r;
1695 BUG_ON(r != 1);
1696 base = kmap_atomic(page);
1697 set_bit(bit, base);
1698 kunmap_atomic(base);
1699 set_page_dirty_lock(page);
1700 put_page(page);
1701 return 0;
1702 }
1703
1704 static int log_write(void __user *log_base,
1705 u64 write_address, u64 write_length)
1706 {
1707 u64 write_page = write_address / VHOST_PAGE_SIZE;
1708 int r;
1709
1710 if (!write_length)
1711 return 0;
1712 write_length += write_address % VHOST_PAGE_SIZE;
1713 for (;;) {
1714 u64 base = (u64)(unsigned long)log_base;
1715 u64 log = base + write_page / 8;
1716 int bit = write_page % 8;
1717 if ((u64)(unsigned long)log != log)
1718 return -EFAULT;
1719 r = set_bit_to_user(bit, (void __user *)(unsigned long)log);
1720 if (r < 0)
1721 return r;
1722 if (write_length <= VHOST_PAGE_SIZE)
1723 break;
1724 write_length -= VHOST_PAGE_SIZE;
1725 write_page += 1;
1726 }
1727 return r;
1728 }
1729
1730 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
1731 unsigned int log_num, u64 len)
1732 {
1733 int i, r;
1734
1735 /* Make sure data written is seen before log. */
1736 smp_wmb();
1737 for (i = 0; i < log_num; ++i) {
1738 u64 l = min(log[i].len, len);
1739 r = log_write(vq->log_base, log[i].addr, l);
1740 if (r < 0)
1741 return r;
1742 len -= l;
1743 if (!len) {
1744 if (vq->log_ctx)
1745 eventfd_signal(vq->log_ctx, 1);
1746 return 0;
1747 }
1748 }
1749 /* Length written exceeds what we have stored. This is a bug. */
1750 BUG();
1751 return 0;
1752 }
1753 EXPORT_SYMBOL_GPL(vhost_log_write);
1754
1755 static int vhost_update_used_flags(struct vhost_virtqueue *vq)
1756 {
1757 void __user *used;
1758 if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags),
1759 &vq->used->flags) < 0)
1760 return -EFAULT;
1761 if (unlikely(vq->log_used)) {
1762 /* Make sure the flag is seen before log. */
1763 smp_wmb();
1764 /* Log used flag write. */
1765 used = &vq->used->flags;
1766 log_write(vq->log_base, vq->log_addr +
1767 (used - (void __user *)vq->used),
1768 sizeof vq->used->flags);
1769 if (vq->log_ctx)
1770 eventfd_signal(vq->log_ctx, 1);
1771 }
1772 return 0;
1773 }
1774
1775 static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
1776 {
1777 if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx),
1778 vhost_avail_event(vq)))
1779 return -EFAULT;
1780 if (unlikely(vq->log_used)) {
1781 void __user *used;
1782 /* Make sure the event is seen before log. */
1783 smp_wmb();
1784 /* Log avail event write */
1785 used = vhost_avail_event(vq);
1786 log_write(vq->log_base, vq->log_addr +
1787 (used - (void __user *)vq->used),
1788 sizeof *vhost_avail_event(vq));
1789 if (vq->log_ctx)
1790 eventfd_signal(vq->log_ctx, 1);
1791 }
1792 return 0;
1793 }
1794
1795 int vhost_vq_init_access(struct vhost_virtqueue *vq)
1796 {
1797 __virtio16 last_used_idx;
1798 int r;
1799 bool is_le = vq->is_le;
1800
1801 if (!vq->private_data)
1802 return 0;
1803
1804 vhost_init_is_le(vq);
1805
1806 r = vhost_update_used_flags(vq);
1807 if (r)
1808 goto err;
1809 vq->signalled_used_valid = false;
1810 if (!vq->iotlb &&
1811 !access_ok(VERIFY_READ, &vq->used->idx, sizeof vq->used->idx)) {
1812 r = -EFAULT;
1813 goto err;
1814 }
1815 r = vhost_get_used(vq, last_used_idx, &vq->used->idx);
1816 if (r) {
1817 vq_err(vq, "Can't access used idx at %p\n",
1818 &vq->used->idx);
1819 goto err;
1820 }
1821 vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx);
1822 return 0;
1823
1824 err:
1825 vq->is_le = is_le;
1826 return r;
1827 }
1828 EXPORT_SYMBOL_GPL(vhost_vq_init_access);
1829
1830 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
1831 struct iovec iov[], int iov_size, int access)
1832 {
1833 const struct vhost_umem_node *node;
1834 struct vhost_dev *dev = vq->dev;
1835 struct vhost_umem *umem = dev->iotlb ? dev->iotlb : dev->umem;
1836 struct iovec *_iov;
1837 u64 s = 0;
1838 int ret = 0;
1839
1840 while ((u64)len > s) {
1841 u64 size;
1842 if (unlikely(ret >= iov_size)) {
1843 ret = -ENOBUFS;
1844 break;
1845 }
1846
1847 node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
1848 addr, addr + len - 1);
1849 if (node == NULL || node->start > addr) {
1850 if (umem != dev->iotlb) {
1851 ret = -EFAULT;
1852 break;
1853 }
1854 ret = -EAGAIN;
1855 break;
1856 } else if (!(node->perm & access)) {
1857 ret = -EPERM;
1858 break;
1859 }
1860
1861 _iov = iov + ret;
1862 size = node->size - addr + node->start;
1863 _iov->iov_len = min((u64)len - s, size);
1864 _iov->iov_base = (void __user *)(unsigned long)
1865 (node->userspace_addr + addr - node->start);
1866 s += size;
1867 addr += size;
1868 ++ret;
1869 }
1870
1871 if (ret == -EAGAIN)
1872 vhost_iotlb_miss(vq, addr, access);
1873 return ret;
1874 }
1875
1876 /* Each buffer in the virtqueues is actually a chain of descriptors. This
1877 * function returns the next descriptor in the chain,
1878 * or -1U if we're at the end. */
1879 static unsigned next_desc(struct vhost_virtqueue *vq, struct vring_desc *desc)
1880 {
1881 unsigned int next;
1882
1883 /* If this descriptor says it doesn't chain, we're done. */
1884 if (!(desc->flags & cpu_to_vhost16(vq, VRING_DESC_F_NEXT)))
1885 return -1U;
1886
1887 /* Check they're not leading us off end of descriptors. */
1888 next = vhost16_to_cpu(vq, desc->next);
1889 /* Make sure compiler knows to grab that: we don't want it changing! */
1890 /* We will use the result as an index in an array, so most
1891 * architectures only need a compiler barrier here. */
1892 read_barrier_depends();
1893
1894 return next;
1895 }
1896
1897 static int get_indirect(struct vhost_virtqueue *vq,
1898 struct iovec iov[], unsigned int iov_size,
1899 unsigned int *out_num, unsigned int *in_num,
1900 struct vhost_log *log, unsigned int *log_num,
1901 struct vring_desc *indirect)
1902 {
1903 struct vring_desc desc;
1904 unsigned int i = 0, count, found = 0;
1905 u32 len = vhost32_to_cpu(vq, indirect->len);
1906 struct iov_iter from;
1907 int ret, access;
1908
1909 /* Sanity check */
1910 if (unlikely(len % sizeof desc)) {
1911 vq_err(vq, "Invalid length in indirect descriptor: "
1912 "len 0x%llx not multiple of 0x%zx\n",
1913 (unsigned long long)len,
1914 sizeof desc);
1915 return -EINVAL;
1916 }
1917
1918 ret = translate_desc(vq, vhost64_to_cpu(vq, indirect->addr), len, vq->indirect,
1919 UIO_MAXIOV, VHOST_ACCESS_RO);
1920 if (unlikely(ret < 0)) {
1921 if (ret != -EAGAIN)
1922 vq_err(vq, "Translation failure %d in indirect.\n", ret);
1923 return ret;
1924 }
1925 iov_iter_init(&from, READ, vq->indirect, ret, len);
1926
1927 /* We will use the result as an address to read from, so most
1928 * architectures only need a compiler barrier here. */
1929 read_barrier_depends();
1930
1931 count = len / sizeof desc;
1932 /* Buffers are chained via a 16 bit next field, so
1933 * we can have at most 2^16 of these. */
1934 if (unlikely(count > USHRT_MAX + 1)) {
1935 vq_err(vq, "Indirect buffer length too big: %d\n",
1936 indirect->len);
1937 return -E2BIG;
1938 }
1939
1940 do {
1941 unsigned iov_count = *in_num + *out_num;
1942 if (unlikely(++found > count)) {
1943 vq_err(vq, "Loop detected: last one at %u "
1944 "indirect size %u\n",
1945 i, count);
1946 return -EINVAL;
1947 }
1948 if (unlikely(!copy_from_iter_full(&desc, sizeof(desc), &from))) {
1949 vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
1950 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
1951 return -EINVAL;
1952 }
1953 if (unlikely(desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT))) {
1954 vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n",
1955 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
1956 return -EINVAL;
1957 }
1958
1959 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
1960 access = VHOST_ACCESS_WO;
1961 else
1962 access = VHOST_ACCESS_RO;
1963
1964 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
1965 vhost32_to_cpu(vq, desc.len), iov + iov_count,
1966 iov_size - iov_count, access);
1967 if (unlikely(ret < 0)) {
1968 if (ret != -EAGAIN)
1969 vq_err(vq, "Translation failure %d indirect idx %d\n",
1970 ret, i);
1971 return ret;
1972 }
1973 /* If this is an input descriptor, increment that count. */
1974 if (access == VHOST_ACCESS_WO) {
1975 *in_num += ret;
1976 if (unlikely(log)) {
1977 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
1978 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
1979 ++*log_num;
1980 }
1981 } else {
1982 /* If it's an output descriptor, they're all supposed
1983 * to come before any input descriptors. */
1984 if (unlikely(*in_num)) {
1985 vq_err(vq, "Indirect descriptor "
1986 "has out after in: idx %d\n", i);
1987 return -EINVAL;
1988 }
1989 *out_num += ret;
1990 }
1991 } while ((i = next_desc(vq, &desc)) != -1);
1992 return 0;
1993 }
1994
1995 /* This looks in the virtqueue and for the first available buffer, and converts
1996 * it to an iovec for convenient access. Since descriptors consist of some
1997 * number of output then some number of input descriptors, it's actually two
1998 * iovecs, but we pack them into one and note how many of each there were.
1999 *
2000 * This function returns the descriptor number found, or vq->num (which is
2001 * never a valid descriptor number) if none was found. A negative code is
2002 * returned on error. */
2003 int vhost_get_vq_desc(struct vhost_virtqueue *vq,
2004 struct iovec iov[], unsigned int iov_size,
2005 unsigned int *out_num, unsigned int *in_num,
2006 struct vhost_log *log, unsigned int *log_num)
2007 {
2008 struct vring_desc desc;
2009 unsigned int i, head, found = 0;
2010 u16 last_avail_idx;
2011 __virtio16 avail_idx;
2012 __virtio16 ring_head;
2013 int ret, access;
2014
2015 /* Check it isn't doing very strange things with descriptor numbers. */
2016 last_avail_idx = vq->last_avail_idx;
2017
2018 if (vq->avail_idx == vq->last_avail_idx) {
2019 if (unlikely(vhost_get_avail(vq, avail_idx, &vq->avail->idx))) {
2020 vq_err(vq, "Failed to access avail idx at %p\n",
2021 &vq->avail->idx);
2022 return -EFAULT;
2023 }
2024 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2025
2026 if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) {
2027 vq_err(vq, "Guest moved used index from %u to %u",
2028 last_avail_idx, vq->avail_idx);
2029 return -EFAULT;
2030 }
2031
2032 /* If there's nothing new since last we looked, return
2033 * invalid.
2034 */
2035 if (vq->avail_idx == last_avail_idx)
2036 return vq->num;
2037
2038 /* Only get avail ring entries after they have been
2039 * exposed by guest.
2040 */
2041 smp_rmb();
2042 }
2043
2044 /* Grab the next descriptor number they're advertising, and increment
2045 * the index we've seen. */
2046 if (unlikely(vhost_get_avail(vq, ring_head,
2047 &vq->avail->ring[last_avail_idx & (vq->num - 1)]))) {
2048 vq_err(vq, "Failed to read head: idx %d address %p\n",
2049 last_avail_idx,
2050 &vq->avail->ring[last_avail_idx % vq->num]);
2051 return -EFAULT;
2052 }
2053
2054 head = vhost16_to_cpu(vq, ring_head);
2055
2056 /* If their number is silly, that's an error. */
2057 if (unlikely(head >= vq->num)) {
2058 vq_err(vq, "Guest says index %u > %u is available",
2059 head, vq->num);
2060 return -EINVAL;
2061 }
2062
2063 /* When we start there are none of either input nor output. */
2064 *out_num = *in_num = 0;
2065 if (unlikely(log))
2066 *log_num = 0;
2067
2068 i = head;
2069 do {
2070 unsigned iov_count = *in_num + *out_num;
2071 if (unlikely(i >= vq->num)) {
2072 vq_err(vq, "Desc index is %u > %u, head = %u",
2073 i, vq->num, head);
2074 return -EINVAL;
2075 }
2076 if (unlikely(++found > vq->num)) {
2077 vq_err(vq, "Loop detected: last one at %u "
2078 "vq size %u head %u\n",
2079 i, vq->num, head);
2080 return -EINVAL;
2081 }
2082 ret = vhost_copy_from_user(vq, &desc, vq->desc + i,
2083 sizeof desc);
2084 if (unlikely(ret)) {
2085 vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
2086 i, vq->desc + i);
2087 return -EFAULT;
2088 }
2089 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT)) {
2090 ret = get_indirect(vq, iov, iov_size,
2091 out_num, in_num,
2092 log, log_num, &desc);
2093 if (unlikely(ret < 0)) {
2094 if (ret != -EAGAIN)
2095 vq_err(vq, "Failure detected "
2096 "in indirect descriptor at idx %d\n", i);
2097 return ret;
2098 }
2099 continue;
2100 }
2101
2102 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
2103 access = VHOST_ACCESS_WO;
2104 else
2105 access = VHOST_ACCESS_RO;
2106 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
2107 vhost32_to_cpu(vq, desc.len), iov + iov_count,
2108 iov_size - iov_count, access);
2109 if (unlikely(ret < 0)) {
2110 if (ret != -EAGAIN)
2111 vq_err(vq, "Translation failure %d descriptor idx %d\n",
2112 ret, i);
2113 return ret;
2114 }
2115 if (access == VHOST_ACCESS_WO) {
2116 /* If this is an input descriptor,
2117 * increment that count. */
2118 *in_num += ret;
2119 if (unlikely(log)) {
2120 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
2121 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
2122 ++*log_num;
2123 }
2124 } else {
2125 /* If it's an output descriptor, they're all supposed
2126 * to come before any input descriptors. */
2127 if (unlikely(*in_num)) {
2128 vq_err(vq, "Descriptor has out after in: "
2129 "idx %d\n", i);
2130 return -EINVAL;
2131 }
2132 *out_num += ret;
2133 }
2134 } while ((i = next_desc(vq, &desc)) != -1);
2135
2136 /* On success, increment avail index. */
2137 vq->last_avail_idx++;
2138
2139 /* Assume notifications from guest are disabled at this point,
2140 * if they aren't we would need to update avail_event index. */
2141 BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY));
2142 return head;
2143 }
2144 EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
2145
2146 /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
2147 void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n)
2148 {
2149 vq->last_avail_idx -= n;
2150 }
2151 EXPORT_SYMBOL_GPL(vhost_discard_vq_desc);
2152
2153 /* After we've used one of their buffers, we tell them about it. We'll then
2154 * want to notify the guest, using eventfd. */
2155 int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
2156 {
2157 struct vring_used_elem heads = {
2158 cpu_to_vhost32(vq, head),
2159 cpu_to_vhost32(vq, len)
2160 };
2161
2162 return vhost_add_used_n(vq, &heads, 1);
2163 }
2164 EXPORT_SYMBOL_GPL(vhost_add_used);
2165
2166 static int __vhost_add_used_n(struct vhost_virtqueue *vq,
2167 struct vring_used_elem *heads,
2168 unsigned count)
2169 {
2170 struct vring_used_elem __user *used;
2171 u16 old, new;
2172 int start;
2173
2174 start = vq->last_used_idx & (vq->num - 1);
2175 used = vq->used->ring + start;
2176 if (count == 1) {
2177 if (vhost_put_user(vq, heads[0].id, &used->id)) {
2178 vq_err(vq, "Failed to write used id");
2179 return -EFAULT;
2180 }
2181 if (vhost_put_user(vq, heads[0].len, &used->len)) {
2182 vq_err(vq, "Failed to write used len");
2183 return -EFAULT;
2184 }
2185 } else if (vhost_copy_to_user(vq, used, heads, count * sizeof *used)) {
2186 vq_err(vq, "Failed to write used");
2187 return -EFAULT;
2188 }
2189 if (unlikely(vq->log_used)) {
2190 /* Make sure data is seen before log. */
2191 smp_wmb();
2192 /* Log used ring entry write. */
2193 log_write(vq->log_base,
2194 vq->log_addr +
2195 ((void __user *)used - (void __user *)vq->used),
2196 count * sizeof *used);
2197 }
2198 old = vq->last_used_idx;
2199 new = (vq->last_used_idx += count);
2200 /* If the driver never bothers to signal in a very long while,
2201 * used index might wrap around. If that happens, invalidate
2202 * signalled_used index we stored. TODO: make sure driver
2203 * signals at least once in 2^16 and remove this. */
2204 if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old)))
2205 vq->signalled_used_valid = false;
2206 return 0;
2207 }
2208
2209 /* After we've used one of their buffers, we tell them about it. We'll then
2210 * want to notify the guest, using eventfd. */
2211 int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
2212 unsigned count)
2213 {
2214 int start, n, r;
2215
2216 start = vq->last_used_idx & (vq->num - 1);
2217 n = vq->num - start;
2218 if (n < count) {
2219 r = __vhost_add_used_n(vq, heads, n);
2220 if (r < 0)
2221 return r;
2222 heads += n;
2223 count -= n;
2224 }
2225 r = __vhost_add_used_n(vq, heads, count);
2226
2227 /* Make sure buffer is written before we update index. */
2228 smp_wmb();
2229 if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx),
2230 &vq->used->idx)) {
2231 vq_err(vq, "Failed to increment used idx");
2232 return -EFAULT;
2233 }
2234 if (unlikely(vq->log_used)) {
2235 /* Log used index update. */
2236 log_write(vq->log_base,
2237 vq->log_addr + offsetof(struct vring_used, idx),
2238 sizeof vq->used->idx);
2239 if (vq->log_ctx)
2240 eventfd_signal(vq->log_ctx, 1);
2241 }
2242 return r;
2243 }
2244 EXPORT_SYMBOL_GPL(vhost_add_used_n);
2245
2246 static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2247 {
2248 __u16 old, new;
2249 __virtio16 event;
2250 bool v;
2251 /* Flush out used index updates. This is paired
2252 * with the barrier that the Guest executes when enabling
2253 * interrupts. */
2254 smp_mb();
2255
2256 if (vhost_has_feature(vq, VIRTIO_F_NOTIFY_ON_EMPTY) &&
2257 unlikely(vq->avail_idx == vq->last_avail_idx))
2258 return true;
2259
2260 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2261 __virtio16 flags;
2262 if (vhost_get_avail(vq, flags, &vq->avail->flags)) {
2263 vq_err(vq, "Failed to get flags");
2264 return true;
2265 }
2266 return !(flags & cpu_to_vhost16(vq, VRING_AVAIL_F_NO_INTERRUPT));
2267 }
2268 old = vq->signalled_used;
2269 v = vq->signalled_used_valid;
2270 new = vq->signalled_used = vq->last_used_idx;
2271 vq->signalled_used_valid = true;
2272
2273 if (unlikely(!v))
2274 return true;
2275
2276 if (vhost_get_avail(vq, event, vhost_used_event(vq))) {
2277 vq_err(vq, "Failed to get used event idx");
2278 return true;
2279 }
2280 return vring_need_event(vhost16_to_cpu(vq, event), new, old);
2281 }
2282
2283 /* This actually signals the guest, using eventfd. */
2284 void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2285 {
2286 /* Signal the Guest tell them we used something up. */
2287 if (vq->call_ctx && vhost_notify(dev, vq))
2288 eventfd_signal(vq->call_ctx, 1);
2289 }
2290 EXPORT_SYMBOL_GPL(vhost_signal);
2291
2292 /* And here's the combo meal deal. Supersize me! */
2293 void vhost_add_used_and_signal(struct vhost_dev *dev,
2294 struct vhost_virtqueue *vq,
2295 unsigned int head, int len)
2296 {
2297 vhost_add_used(vq, head, len);
2298 vhost_signal(dev, vq);
2299 }
2300 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal);
2301
2302 /* multi-buffer version of vhost_add_used_and_signal */
2303 void vhost_add_used_and_signal_n(struct vhost_dev *dev,
2304 struct vhost_virtqueue *vq,
2305 struct vring_used_elem *heads, unsigned count)
2306 {
2307 vhost_add_used_n(vq, heads, count);
2308 vhost_signal(dev, vq);
2309 }
2310 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
2311
2312 /* return true if we're sure that avaiable ring is empty */
2313 bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2314 {
2315 __virtio16 avail_idx;
2316 int r;
2317
2318 if (vq->avail_idx != vq->last_avail_idx)
2319 return false;
2320
2321 r = vhost_get_avail(vq, avail_idx, &vq->avail->idx);
2322 if (unlikely(r))
2323 return false;
2324 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2325
2326 return vq->avail_idx == vq->last_avail_idx;
2327 }
2328 EXPORT_SYMBOL_GPL(vhost_vq_avail_empty);
2329
2330 /* OK, now we need to know about added descriptors. */
2331 bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2332 {
2333 __virtio16 avail_idx;
2334 int r;
2335
2336 if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
2337 return false;
2338 vq->used_flags &= ~VRING_USED_F_NO_NOTIFY;
2339 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2340 r = vhost_update_used_flags(vq);
2341 if (r) {
2342 vq_err(vq, "Failed to enable notification at %p: %d\n",
2343 &vq->used->flags, r);
2344 return false;
2345 }
2346 } else {
2347 r = vhost_update_avail_event(vq, vq->avail_idx);
2348 if (r) {
2349 vq_err(vq, "Failed to update avail event index at %p: %d\n",
2350 vhost_avail_event(vq), r);
2351 return false;
2352 }
2353 }
2354 /* They could have slipped one in as we were doing that: make
2355 * sure it's written, then check again. */
2356 smp_mb();
2357 r = vhost_get_avail(vq, avail_idx, &vq->avail->idx);
2358 if (r) {
2359 vq_err(vq, "Failed to check avail idx at %p: %d\n",
2360 &vq->avail->idx, r);
2361 return false;
2362 }
2363
2364 return vhost16_to_cpu(vq, avail_idx) != vq->avail_idx;
2365 }
2366 EXPORT_SYMBOL_GPL(vhost_enable_notify);
2367
2368 /* We don't need to be notified again. */
2369 void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2370 {
2371 int r;
2372
2373 if (vq->used_flags & VRING_USED_F_NO_NOTIFY)
2374 return;
2375 vq->used_flags |= VRING_USED_F_NO_NOTIFY;
2376 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2377 r = vhost_update_used_flags(vq);
2378 if (r)
2379 vq_err(vq, "Failed to enable notification at %p: %d\n",
2380 &vq->used->flags, r);
2381 }
2382 }
2383 EXPORT_SYMBOL_GPL(vhost_disable_notify);
2384
2385 /* Create a new message. */
2386 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type)
2387 {
2388 struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL);
2389 if (!node)
2390 return NULL;
2391
2392 /* Make sure all padding within the structure is initialized. */
2393 memset(&node->msg, 0, sizeof node->msg);
2394 node->vq = vq;
2395 node->msg.type = type;
2396 return node;
2397 }
2398 EXPORT_SYMBOL_GPL(vhost_new_msg);
2399
2400 void vhost_enqueue_msg(struct vhost_dev *dev, struct list_head *head,
2401 struct vhost_msg_node *node)
2402 {
2403 spin_lock(&dev->iotlb_lock);
2404 list_add_tail(&node->node, head);
2405 spin_unlock(&dev->iotlb_lock);
2406
2407 wake_up_interruptible_poll(&dev->wait, POLLIN | POLLRDNORM);
2408 }
2409 EXPORT_SYMBOL_GPL(vhost_enqueue_msg);
2410
2411 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
2412 struct list_head *head)
2413 {
2414 struct vhost_msg_node *node = NULL;
2415
2416 spin_lock(&dev->iotlb_lock);
2417 if (!list_empty(head)) {
2418 node = list_first_entry(head, struct vhost_msg_node,
2419 node);
2420 list_del(&node->node);
2421 }
2422 spin_unlock(&dev->iotlb_lock);
2423
2424 return node;
2425 }
2426 EXPORT_SYMBOL_GPL(vhost_dequeue_msg);
2427
2428
2429 static int __init vhost_init(void)
2430 {
2431 return 0;
2432 }
2433
2434 static void __exit vhost_exit(void)
2435 {
2436 }
2437
2438 module_init(vhost_init);
2439 module_exit(vhost_exit);
2440
2441 MODULE_VERSION("0.0.1");
2442 MODULE_LICENSE("GPL v2");
2443 MODULE_AUTHOR("Michael S. Tsirkin");
2444 MODULE_DESCRIPTION("Host kernel accelerator for virtio");
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