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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
34 #include "vhost.h"
35
36 static ushort max_mem_regions = 64;
37 module_param(max_mem_regions, ushort, 0444);
38 MODULE_PARM_DESC(max_mem_regions,
39 "Maximum number of memory regions in memory map. (default: 64)");
40 static int max_iotlb_entries = 2048;
41 module_param(max_iotlb_entries, int, 0444);
42 MODULE_PARM_DESC(max_iotlb_entries,
43 "Maximum number of iotlb entries. (default: 2048)");
44
45 enum {
46 VHOST_MEMORY_F_LOG = 0x1,
47 };
48
49 #define vhost_used_event(vq) ((__virtio16 __user *)&vq->avail->ring[vq->num])
50 #define vhost_avail_event(vq) ((__virtio16 __user *)&vq->used->ring[vq->num])
51
52 INTERVAL_TREE_DEFINE(struct vhost_umem_node,
53 rb, __u64, __subtree_last,
54 START, LAST, static inline, vhost_umem_interval_tree);
55
56 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
57 static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
58 {
59 vq->user_be = !virtio_legacy_is_little_endian();
60 }
61
62 static void vhost_enable_cross_endian_big(struct vhost_virtqueue *vq)
63 {
64 vq->user_be = true;
65 }
66
67 static void vhost_enable_cross_endian_little(struct vhost_virtqueue *vq)
68 {
69 vq->user_be = false;
70 }
71
72 static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
73 {
74 struct vhost_vring_state s;
75
76 if (vq->private_data)
77 return -EBUSY;
78
79 if (copy_from_user(&s, argp, sizeof(s)))
80 return -EFAULT;
81
82 if (s.num != VHOST_VRING_LITTLE_ENDIAN &&
83 s.num != VHOST_VRING_BIG_ENDIAN)
84 return -EINVAL;
85
86 if (s.num == VHOST_VRING_BIG_ENDIAN)
87 vhost_enable_cross_endian_big(vq);
88 else
89 vhost_enable_cross_endian_little(vq);
90
91 return 0;
92 }
93
94 static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
95 int __user *argp)
96 {
97 struct vhost_vring_state s = {
98 .index = idx,
99 .num = vq->user_be
100 };
101
102 if (copy_to_user(argp, &s, sizeof(s)))
103 return -EFAULT;
104
105 return 0;
106 }
107
108 static void vhost_init_is_le(struct vhost_virtqueue *vq)
109 {
110 /* Note for legacy virtio: user_be is initialized at reset time
111 * according to the host endianness. If userspace does not set an
112 * explicit endianness, the default behavior is native endian, as
113 * expected by legacy virtio.
114 */
115 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1) || !vq->user_be;
116 }
117 #else
118 static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
119 {
120 }
121
122 static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
123 {
124 return -ENOIOCTLCMD;
125 }
126
127 static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
128 int __user *argp)
129 {
130 return -ENOIOCTLCMD;
131 }
132
133 static void vhost_init_is_le(struct vhost_virtqueue *vq)
134 {
135 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1)
136 || virtio_legacy_is_little_endian();
137 }
138 #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
139
140 static void vhost_reset_is_le(struct vhost_virtqueue *vq)
141 {
142 vhost_init_is_le(vq);
143 }
144
145 struct vhost_flush_struct {
146 struct vhost_work work;
147 struct completion wait_event;
148 };
149
150 static void vhost_flush_work(struct vhost_work *work)
151 {
152 struct vhost_flush_struct *s;
153
154 s = container_of(work, struct vhost_flush_struct, work);
155 complete(&s->wait_event);
156 }
157
158 static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
159 poll_table *pt)
160 {
161 struct vhost_poll *poll;
162
163 poll = container_of(pt, struct vhost_poll, table);
164 poll->wqh = wqh;
165 add_wait_queue(wqh, &poll->wait);
166 }
167
168 static int vhost_poll_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync,
169 void *key)
170 {
171 struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait);
172
173 if (!((unsigned long)key & poll->mask))
174 return 0;
175
176 vhost_poll_queue(poll);
177 return 0;
178 }
179
180 void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn)
181 {
182 clear_bit(VHOST_WORK_QUEUED, &work->flags);
183 work->fn = fn;
184 init_waitqueue_head(&work->done);
185 }
186 EXPORT_SYMBOL_GPL(vhost_work_init);
187
188 /* Init poll structure */
189 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn,
190 unsigned long mask, struct vhost_dev *dev)
191 {
192 init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup);
193 init_poll_funcptr(&poll->table, vhost_poll_func);
194 poll->mask = mask;
195 poll->dev = dev;
196 poll->wqh = NULL;
197
198 vhost_work_init(&poll->work, fn);
199 }
200 EXPORT_SYMBOL_GPL(vhost_poll_init);
201
202 /* Start polling a file. We add ourselves to file's wait queue. The caller must
203 * keep a reference to a file until after vhost_poll_stop is called. */
204 int vhost_poll_start(struct vhost_poll *poll, struct file *file)
205 {
206 unsigned long mask;
207 int ret = 0;
208
209 if (poll->wqh)
210 return 0;
211
212 mask = file->f_op->poll(file, &poll->table);
213 if (mask)
214 vhost_poll_wakeup(&poll->wait, 0, 0, (void *)mask);
215 if (mask & POLLERR) {
216 if (poll->wqh)
217 remove_wait_queue(poll->wqh, &poll->wait);
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_DESC);
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 vhost_dev_lock_vqs(dev);
998 switch (msg->type) {
999 case VHOST_IOTLB_UPDATE:
1000 if (!dev->iotlb) {
1001 ret = -EFAULT;
1002 break;
1003 }
1004 if (umem_access_ok(msg->uaddr, msg->size, msg->perm)) {
1005 ret = -EFAULT;
1006 break;
1007 }
1008 vhost_vq_meta_reset(dev);
1009 if (vhost_new_umem_range(dev->iotlb, msg->iova, msg->size,
1010 msg->iova + msg->size - 1,
1011 msg->uaddr, msg->perm)) {
1012 ret = -ENOMEM;
1013 break;
1014 }
1015 vhost_iotlb_notify_vq(dev, msg);
1016 break;
1017 case VHOST_IOTLB_INVALIDATE:
1018 if (!dev->iotlb) {
1019 ret = -EFAULT;
1020 break;
1021 }
1022 vhost_vq_meta_reset(dev);
1023 vhost_del_umem_range(dev->iotlb, msg->iova,
1024 msg->iova + msg->size - 1);
1025 break;
1026 default:
1027 ret = -EINVAL;
1028 break;
1029 }
1030
1031 vhost_dev_unlock_vqs(dev);
1032 return ret;
1033 }
1034 ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
1035 struct iov_iter *from)
1036 {
1037 struct vhost_msg_node node;
1038 unsigned size = sizeof(struct vhost_msg);
1039 size_t ret;
1040 int err;
1041
1042 if (iov_iter_count(from) < size)
1043 return 0;
1044 ret = copy_from_iter(&node.msg, size, from);
1045 if (ret != size)
1046 goto done;
1047
1048 switch (node.msg.type) {
1049 case VHOST_IOTLB_MSG:
1050 err = vhost_process_iotlb_msg(dev, &node.msg.iotlb);
1051 if (err)
1052 ret = err;
1053 break;
1054 default:
1055 ret = -EINVAL;
1056 break;
1057 }
1058
1059 done:
1060 return ret;
1061 }
1062 EXPORT_SYMBOL(vhost_chr_write_iter);
1063
1064 unsigned int vhost_chr_poll(struct file *file, struct vhost_dev *dev,
1065 poll_table *wait)
1066 {
1067 unsigned int mask = 0;
1068
1069 poll_wait(file, &dev->wait, wait);
1070
1071 if (!list_empty(&dev->read_list))
1072 mask |= POLLIN | POLLRDNORM;
1073
1074 return mask;
1075 }
1076 EXPORT_SYMBOL(vhost_chr_poll);
1077
1078 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
1079 int noblock)
1080 {
1081 DEFINE_WAIT(wait);
1082 struct vhost_msg_node *node;
1083 ssize_t ret = 0;
1084 unsigned size = sizeof(struct vhost_msg);
1085
1086 if (iov_iter_count(to) < size)
1087 return 0;
1088
1089 while (1) {
1090 if (!noblock)
1091 prepare_to_wait(&dev->wait, &wait,
1092 TASK_INTERRUPTIBLE);
1093
1094 node = vhost_dequeue_msg(dev, &dev->read_list);
1095 if (node)
1096 break;
1097 if (noblock) {
1098 ret = -EAGAIN;
1099 break;
1100 }
1101 if (signal_pending(current)) {
1102 ret = -ERESTARTSYS;
1103 break;
1104 }
1105 if (!dev->iotlb) {
1106 ret = -EBADFD;
1107 break;
1108 }
1109
1110 schedule();
1111 }
1112
1113 if (!noblock)
1114 finish_wait(&dev->wait, &wait);
1115
1116 if (node) {
1117 ret = copy_to_iter(&node->msg, size, to);
1118
1119 if (ret != size || node->msg.type != VHOST_IOTLB_MISS) {
1120 kfree(node);
1121 return ret;
1122 }
1123
1124 vhost_enqueue_msg(dev, &dev->pending_list, node);
1125 }
1126
1127 return ret;
1128 }
1129 EXPORT_SYMBOL_GPL(vhost_chr_read_iter);
1130
1131 static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access)
1132 {
1133 struct vhost_dev *dev = vq->dev;
1134 struct vhost_msg_node *node;
1135 struct vhost_iotlb_msg *msg;
1136
1137 node = vhost_new_msg(vq, VHOST_IOTLB_MISS);
1138 if (!node)
1139 return -ENOMEM;
1140
1141 msg = &node->msg.iotlb;
1142 msg->type = VHOST_IOTLB_MISS;
1143 msg->iova = iova;
1144 msg->perm = access;
1145
1146 vhost_enqueue_msg(dev, &dev->read_list, node);
1147
1148 return 0;
1149 }
1150
1151 static int vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
1152 struct vring_desc __user *desc,
1153 struct vring_avail __user *avail,
1154 struct vring_used __user *used)
1155
1156 {
1157 size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
1158
1159 return access_ok(VERIFY_READ, desc, num * sizeof *desc) &&
1160 access_ok(VERIFY_READ, avail,
1161 sizeof *avail + num * sizeof *avail->ring + s) &&
1162 access_ok(VERIFY_WRITE, used,
1163 sizeof *used + num * sizeof *used->ring + s);
1164 }
1165
1166 static void vhost_vq_meta_update(struct vhost_virtqueue *vq,
1167 const struct vhost_umem_node *node,
1168 int type)
1169 {
1170 int access = (type == VHOST_ADDR_USED) ?
1171 VHOST_ACCESS_WO : VHOST_ACCESS_RO;
1172
1173 if (likely(node->perm & access))
1174 vq->meta_iotlb[type] = node;
1175 }
1176
1177 static int iotlb_access_ok(struct vhost_virtqueue *vq,
1178 int access, u64 addr, u64 len, int type)
1179 {
1180 const struct vhost_umem_node *node;
1181 struct vhost_umem *umem = vq->iotlb;
1182 u64 s = 0, size, orig_addr = addr, last = addr + len - 1;
1183
1184 if (vhost_vq_meta_fetch(vq, addr, len, type))
1185 return true;
1186
1187 while (len > s) {
1188 node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
1189 addr,
1190 last);
1191 if (node == NULL || node->start > addr) {
1192 vhost_iotlb_miss(vq, addr, access);
1193 return false;
1194 } else if (!(node->perm & access)) {
1195 /* Report the possible access violation by
1196 * request another translation from userspace.
1197 */
1198 return false;
1199 }
1200
1201 size = node->size - addr + node->start;
1202
1203 if (orig_addr == addr && size >= len)
1204 vhost_vq_meta_update(vq, node, type);
1205
1206 s += size;
1207 addr += size;
1208 }
1209
1210 return true;
1211 }
1212
1213 int vq_iotlb_prefetch(struct vhost_virtqueue *vq)
1214 {
1215 size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
1216 unsigned int num = vq->num;
1217
1218 if (!vq->iotlb)
1219 return 1;
1220
1221 return iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->desc,
1222 num * sizeof(*vq->desc), VHOST_ADDR_DESC) &&
1223 iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->avail,
1224 sizeof *vq->avail +
1225 num * sizeof(*vq->avail->ring) + s,
1226 VHOST_ADDR_AVAIL) &&
1227 iotlb_access_ok(vq, VHOST_ACCESS_WO, (u64)(uintptr_t)vq->used,
1228 sizeof *vq->used +
1229 num * sizeof(*vq->used->ring) + s,
1230 VHOST_ADDR_USED);
1231 }
1232 EXPORT_SYMBOL_GPL(vq_iotlb_prefetch);
1233
1234 /* Can we log writes? */
1235 /* Caller should have device mutex but not vq mutex */
1236 int vhost_log_access_ok(struct vhost_dev *dev)
1237 {
1238 return memory_access_ok(dev, dev->umem, 1);
1239 }
1240 EXPORT_SYMBOL_GPL(vhost_log_access_ok);
1241
1242 /* Verify access for write logging. */
1243 /* Caller should have vq mutex and device mutex */
1244 static int vq_log_access_ok(struct vhost_virtqueue *vq,
1245 void __user *log_base)
1246 {
1247 size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
1248
1249 return vq_memory_access_ok(log_base, vq->umem,
1250 vhost_has_feature(vq, VHOST_F_LOG_ALL)) &&
1251 (!vq->log_used || log_access_ok(log_base, vq->log_addr,
1252 sizeof *vq->used +
1253 vq->num * sizeof *vq->used->ring + s));
1254 }
1255
1256 /* Can we start vq? */
1257 /* Caller should have vq mutex and device mutex */
1258 int vhost_vq_access_ok(struct vhost_virtqueue *vq)
1259 {
1260 if (vq->iotlb) {
1261 /* When device IOTLB was used, the access validation
1262 * will be validated during prefetching.
1263 */
1264 return 1;
1265 }
1266 return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used) &&
1267 vq_log_access_ok(vq, vq->log_base);
1268 }
1269 EXPORT_SYMBOL_GPL(vhost_vq_access_ok);
1270
1271 static struct vhost_umem *vhost_umem_alloc(void)
1272 {
1273 struct vhost_umem *umem = kvzalloc(sizeof(*umem), GFP_KERNEL);
1274
1275 if (!umem)
1276 return NULL;
1277
1278 umem->umem_tree = RB_ROOT_CACHED;
1279 umem->numem = 0;
1280 INIT_LIST_HEAD(&umem->umem_list);
1281
1282 return umem;
1283 }
1284
1285 static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
1286 {
1287 struct vhost_memory mem, *newmem;
1288 struct vhost_memory_region *region;
1289 struct vhost_umem *newumem, *oldumem;
1290 unsigned long size = offsetof(struct vhost_memory, regions);
1291 int i;
1292
1293 if (copy_from_user(&mem, m, size))
1294 return -EFAULT;
1295 if (mem.padding)
1296 return -EOPNOTSUPP;
1297 if (mem.nregions > max_mem_regions)
1298 return -E2BIG;
1299 newmem = kvzalloc(size + mem.nregions * sizeof(*m->regions), GFP_KERNEL);
1300 if (!newmem)
1301 return -ENOMEM;
1302
1303 memcpy(newmem, &mem, size);
1304 if (copy_from_user(newmem->regions, m->regions,
1305 mem.nregions * sizeof *m->regions)) {
1306 kvfree(newmem);
1307 return -EFAULT;
1308 }
1309
1310 newumem = vhost_umem_alloc();
1311 if (!newumem) {
1312 kvfree(newmem);
1313 return -ENOMEM;
1314 }
1315
1316 for (region = newmem->regions;
1317 region < newmem->regions + mem.nregions;
1318 region++) {
1319 if (vhost_new_umem_range(newumem,
1320 region->guest_phys_addr,
1321 region->memory_size,
1322 region->guest_phys_addr +
1323 region->memory_size - 1,
1324 region->userspace_addr,
1325 VHOST_ACCESS_RW))
1326 goto err;
1327 }
1328
1329 if (!memory_access_ok(d, newumem, 0))
1330 goto err;
1331
1332 oldumem = d->umem;
1333 d->umem = newumem;
1334
1335 /* All memory accesses are done under some VQ mutex. */
1336 for (i = 0; i < d->nvqs; ++i) {
1337 mutex_lock(&d->vqs[i]->mutex);
1338 d->vqs[i]->umem = newumem;
1339 mutex_unlock(&d->vqs[i]->mutex);
1340 }
1341
1342 kvfree(newmem);
1343 vhost_umem_clean(oldumem);
1344 return 0;
1345
1346 err:
1347 vhost_umem_clean(newumem);
1348 kvfree(newmem);
1349 return -EFAULT;
1350 }
1351
1352 long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp)
1353 {
1354 struct file *eventfp, *filep = NULL;
1355 bool pollstart = false, pollstop = false;
1356 struct eventfd_ctx *ctx = NULL;
1357 u32 __user *idxp = argp;
1358 struct vhost_virtqueue *vq;
1359 struct vhost_vring_state s;
1360 struct vhost_vring_file f;
1361 struct vhost_vring_addr a;
1362 u32 idx;
1363 long r;
1364
1365 r = get_user(idx, idxp);
1366 if (r < 0)
1367 return r;
1368 if (idx >= d->nvqs)
1369 return -ENOBUFS;
1370
1371 vq = d->vqs[idx];
1372
1373 mutex_lock(&vq->mutex);
1374
1375 switch (ioctl) {
1376 case VHOST_SET_VRING_NUM:
1377 /* Resizing ring with an active backend?
1378 * You don't want to do that. */
1379 if (vq->private_data) {
1380 r = -EBUSY;
1381 break;
1382 }
1383 if (copy_from_user(&s, argp, sizeof s)) {
1384 r = -EFAULT;
1385 break;
1386 }
1387 if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) {
1388 r = -EINVAL;
1389 break;
1390 }
1391 vq->num = s.num;
1392 break;
1393 case VHOST_SET_VRING_BASE:
1394 /* Moving base with an active backend?
1395 * You don't want to do that. */
1396 if (vq->private_data) {
1397 r = -EBUSY;
1398 break;
1399 }
1400 if (copy_from_user(&s, argp, sizeof s)) {
1401 r = -EFAULT;
1402 break;
1403 }
1404 if (s.num > 0xffff) {
1405 r = -EINVAL;
1406 break;
1407 }
1408 vq->last_avail_idx = s.num;
1409 /* Forget the cached index value. */
1410 vq->avail_idx = vq->last_avail_idx;
1411 break;
1412 case VHOST_GET_VRING_BASE:
1413 s.index = idx;
1414 s.num = vq->last_avail_idx;
1415 if (copy_to_user(argp, &s, sizeof s))
1416 r = -EFAULT;
1417 break;
1418 case VHOST_SET_VRING_ADDR:
1419 if (copy_from_user(&a, argp, sizeof a)) {
1420 r = -EFAULT;
1421 break;
1422 }
1423 if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) {
1424 r = -EOPNOTSUPP;
1425 break;
1426 }
1427 /* For 32bit, verify that the top 32bits of the user
1428 data are set to zero. */
1429 if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr ||
1430 (u64)(unsigned long)a.used_user_addr != a.used_user_addr ||
1431 (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) {
1432 r = -EFAULT;
1433 break;
1434 }
1435
1436 /* Make sure it's safe to cast pointers to vring types. */
1437 BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE);
1438 BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE);
1439 if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) ||
1440 (a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) ||
1441 (a.log_guest_addr & (VRING_USED_ALIGN_SIZE - 1))) {
1442 r = -EINVAL;
1443 break;
1444 }
1445
1446 /* We only verify access here if backend is configured.
1447 * If it is not, we don't as size might not have been setup.
1448 * We will verify when backend is configured. */
1449 if (vq->private_data) {
1450 if (!vq_access_ok(vq, vq->num,
1451 (void __user *)(unsigned long)a.desc_user_addr,
1452 (void __user *)(unsigned long)a.avail_user_addr,
1453 (void __user *)(unsigned long)a.used_user_addr)) {
1454 r = -EINVAL;
1455 break;
1456 }
1457
1458 /* Also validate log access for used ring if enabled. */
1459 if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) &&
1460 !log_access_ok(vq->log_base, a.log_guest_addr,
1461 sizeof *vq->used +
1462 vq->num * sizeof *vq->used->ring)) {
1463 r = -EINVAL;
1464 break;
1465 }
1466 }
1467
1468 vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG));
1469 vq->desc = (void __user *)(unsigned long)a.desc_user_addr;
1470 vq->avail = (void __user *)(unsigned long)a.avail_user_addr;
1471 vq->log_addr = a.log_guest_addr;
1472 vq->used = (void __user *)(unsigned long)a.used_user_addr;
1473 break;
1474 case VHOST_SET_VRING_KICK:
1475 if (copy_from_user(&f, argp, sizeof f)) {
1476 r = -EFAULT;
1477 break;
1478 }
1479 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
1480 if (IS_ERR(eventfp)) {
1481 r = PTR_ERR(eventfp);
1482 break;
1483 }
1484 if (eventfp != vq->kick) {
1485 pollstop = (filep = vq->kick) != NULL;
1486 pollstart = (vq->kick = eventfp) != NULL;
1487 } else
1488 filep = eventfp;
1489 break;
1490 case VHOST_SET_VRING_CALL:
1491 if (copy_from_user(&f, argp, sizeof f)) {
1492 r = -EFAULT;
1493 break;
1494 }
1495 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
1496 if (IS_ERR(eventfp)) {
1497 r = PTR_ERR(eventfp);
1498 break;
1499 }
1500 if (eventfp != vq->call) {
1501 filep = vq->call;
1502 ctx = vq->call_ctx;
1503 vq->call = eventfp;
1504 vq->call_ctx = eventfp ?
1505 eventfd_ctx_fileget(eventfp) : NULL;
1506 } else
1507 filep = eventfp;
1508 break;
1509 case VHOST_SET_VRING_ERR:
1510 if (copy_from_user(&f, argp, sizeof f)) {
1511 r = -EFAULT;
1512 break;
1513 }
1514 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
1515 if (IS_ERR(eventfp)) {
1516 r = PTR_ERR(eventfp);
1517 break;
1518 }
1519 if (eventfp != vq->error) {
1520 filep = vq->error;
1521 vq->error = eventfp;
1522 ctx = vq->error_ctx;
1523 vq->error_ctx = eventfp ?
1524 eventfd_ctx_fileget(eventfp) : NULL;
1525 } else
1526 filep = eventfp;
1527 break;
1528 case VHOST_SET_VRING_ENDIAN:
1529 r = vhost_set_vring_endian(vq, argp);
1530 break;
1531 case VHOST_GET_VRING_ENDIAN:
1532 r = vhost_get_vring_endian(vq, idx, argp);
1533 break;
1534 case VHOST_SET_VRING_BUSYLOOP_TIMEOUT:
1535 if (copy_from_user(&s, argp, sizeof(s))) {
1536 r = -EFAULT;
1537 break;
1538 }
1539 vq->busyloop_timeout = s.num;
1540 break;
1541 case VHOST_GET_VRING_BUSYLOOP_TIMEOUT:
1542 s.index = idx;
1543 s.num = vq->busyloop_timeout;
1544 if (copy_to_user(argp, &s, sizeof(s)))
1545 r = -EFAULT;
1546 break;
1547 default:
1548 r = -ENOIOCTLCMD;
1549 }
1550
1551 if (pollstop && vq->handle_kick)
1552 vhost_poll_stop(&vq->poll);
1553
1554 if (ctx)
1555 eventfd_ctx_put(ctx);
1556 if (filep)
1557 fput(filep);
1558
1559 if (pollstart && vq->handle_kick)
1560 r = vhost_poll_start(&vq->poll, vq->kick);
1561
1562 mutex_unlock(&vq->mutex);
1563
1564 if (pollstop && vq->handle_kick)
1565 vhost_poll_flush(&vq->poll);
1566 return r;
1567 }
1568 EXPORT_SYMBOL_GPL(vhost_vring_ioctl);
1569
1570 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled)
1571 {
1572 struct vhost_umem *niotlb, *oiotlb;
1573 int i;
1574
1575 niotlb = vhost_umem_alloc();
1576 if (!niotlb)
1577 return -ENOMEM;
1578
1579 oiotlb = d->iotlb;
1580 d->iotlb = niotlb;
1581
1582 for (i = 0; i < d->nvqs; ++i) {
1583 mutex_lock(&d->vqs[i]->mutex);
1584 d->vqs[i]->iotlb = niotlb;
1585 mutex_unlock(&d->vqs[i]->mutex);
1586 }
1587
1588 vhost_umem_clean(oiotlb);
1589
1590 return 0;
1591 }
1592 EXPORT_SYMBOL_GPL(vhost_init_device_iotlb);
1593
1594 /* Caller must have device mutex */
1595 long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
1596 {
1597 struct file *eventfp, *filep = NULL;
1598 struct eventfd_ctx *ctx = NULL;
1599 u64 p;
1600 long r;
1601 int i, fd;
1602
1603 /* If you are not the owner, you can become one */
1604 if (ioctl == VHOST_SET_OWNER) {
1605 r = vhost_dev_set_owner(d);
1606 goto done;
1607 }
1608
1609 /* You must be the owner to do anything else */
1610 r = vhost_dev_check_owner(d);
1611 if (r)
1612 goto done;
1613
1614 switch (ioctl) {
1615 case VHOST_SET_MEM_TABLE:
1616 r = vhost_set_memory(d, argp);
1617 break;
1618 case VHOST_SET_LOG_BASE:
1619 if (copy_from_user(&p, argp, sizeof p)) {
1620 r = -EFAULT;
1621 break;
1622 }
1623 if ((u64)(unsigned long)p != p) {
1624 r = -EFAULT;
1625 break;
1626 }
1627 for (i = 0; i < d->nvqs; ++i) {
1628 struct vhost_virtqueue *vq;
1629 void __user *base = (void __user *)(unsigned long)p;
1630 vq = d->vqs[i];
1631 mutex_lock(&vq->mutex);
1632 /* If ring is inactive, will check when it's enabled. */
1633 if (vq->private_data && !vq_log_access_ok(vq, base))
1634 r = -EFAULT;
1635 else
1636 vq->log_base = base;
1637 mutex_unlock(&vq->mutex);
1638 }
1639 break;
1640 case VHOST_SET_LOG_FD:
1641 r = get_user(fd, (int __user *)argp);
1642 if (r < 0)
1643 break;
1644 eventfp = fd == -1 ? NULL : eventfd_fget(fd);
1645 if (IS_ERR(eventfp)) {
1646 r = PTR_ERR(eventfp);
1647 break;
1648 }
1649 if (eventfp != d->log_file) {
1650 filep = d->log_file;
1651 d->log_file = eventfp;
1652 ctx = d->log_ctx;
1653 d->log_ctx = eventfp ?
1654 eventfd_ctx_fileget(eventfp) : NULL;
1655 } else
1656 filep = eventfp;
1657 for (i = 0; i < d->nvqs; ++i) {
1658 mutex_lock(&d->vqs[i]->mutex);
1659 d->vqs[i]->log_ctx = d->log_ctx;
1660 mutex_unlock(&d->vqs[i]->mutex);
1661 }
1662 if (ctx)
1663 eventfd_ctx_put(ctx);
1664 if (filep)
1665 fput(filep);
1666 break;
1667 default:
1668 r = -ENOIOCTLCMD;
1669 break;
1670 }
1671 done:
1672 return r;
1673 }
1674 EXPORT_SYMBOL_GPL(vhost_dev_ioctl);
1675
1676 /* TODO: This is really inefficient. We need something like get_user()
1677 * (instruction directly accesses the data, with an exception table entry
1678 * returning -EFAULT). See Documentation/x86/exception-tables.txt.
1679 */
1680 static int set_bit_to_user(int nr, void __user *addr)
1681 {
1682 unsigned long log = (unsigned long)addr;
1683 struct page *page;
1684 void *base;
1685 int bit = nr + (log % PAGE_SIZE) * 8;
1686 int r;
1687
1688 r = get_user_pages_fast(log, 1, 1, &page);
1689 if (r < 0)
1690 return r;
1691 BUG_ON(r != 1);
1692 base = kmap_atomic(page);
1693 set_bit(bit, base);
1694 kunmap_atomic(base);
1695 set_page_dirty_lock(page);
1696 put_page(page);
1697 return 0;
1698 }
1699
1700 static int log_write(void __user *log_base,
1701 u64 write_address, u64 write_length)
1702 {
1703 u64 write_page = write_address / VHOST_PAGE_SIZE;
1704 int r;
1705
1706 if (!write_length)
1707 return 0;
1708 write_length += write_address % VHOST_PAGE_SIZE;
1709 for (;;) {
1710 u64 base = (u64)(unsigned long)log_base;
1711 u64 log = base + write_page / 8;
1712 int bit = write_page % 8;
1713 if ((u64)(unsigned long)log != log)
1714 return -EFAULT;
1715 r = set_bit_to_user(bit, (void __user *)(unsigned long)log);
1716 if (r < 0)
1717 return r;
1718 if (write_length <= VHOST_PAGE_SIZE)
1719 break;
1720 write_length -= VHOST_PAGE_SIZE;
1721 write_page += 1;
1722 }
1723 return r;
1724 }
1725
1726 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
1727 unsigned int log_num, u64 len)
1728 {
1729 int i, r;
1730
1731 /* Make sure data written is seen before log. */
1732 smp_wmb();
1733 for (i = 0; i < log_num; ++i) {
1734 u64 l = min(log[i].len, len);
1735 r = log_write(vq->log_base, log[i].addr, l);
1736 if (r < 0)
1737 return r;
1738 len -= l;
1739 if (!len) {
1740 if (vq->log_ctx)
1741 eventfd_signal(vq->log_ctx, 1);
1742 return 0;
1743 }
1744 }
1745 /* Length written exceeds what we have stored. This is a bug. */
1746 BUG();
1747 return 0;
1748 }
1749 EXPORT_SYMBOL_GPL(vhost_log_write);
1750
1751 static int vhost_update_used_flags(struct vhost_virtqueue *vq)
1752 {
1753 void __user *used;
1754 if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags),
1755 &vq->used->flags) < 0)
1756 return -EFAULT;
1757 if (unlikely(vq->log_used)) {
1758 /* Make sure the flag is seen before log. */
1759 smp_wmb();
1760 /* Log used flag write. */
1761 used = &vq->used->flags;
1762 log_write(vq->log_base, vq->log_addr +
1763 (used - (void __user *)vq->used),
1764 sizeof vq->used->flags);
1765 if (vq->log_ctx)
1766 eventfd_signal(vq->log_ctx, 1);
1767 }
1768 return 0;
1769 }
1770
1771 static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
1772 {
1773 if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx),
1774 vhost_avail_event(vq)))
1775 return -EFAULT;
1776 if (unlikely(vq->log_used)) {
1777 void __user *used;
1778 /* Make sure the event is seen before log. */
1779 smp_wmb();
1780 /* Log avail event write */
1781 used = vhost_avail_event(vq);
1782 log_write(vq->log_base, vq->log_addr +
1783 (used - (void __user *)vq->used),
1784 sizeof *vhost_avail_event(vq));
1785 if (vq->log_ctx)
1786 eventfd_signal(vq->log_ctx, 1);
1787 }
1788 return 0;
1789 }
1790
1791 int vhost_vq_init_access(struct vhost_virtqueue *vq)
1792 {
1793 __virtio16 last_used_idx;
1794 int r;
1795 bool is_le = vq->is_le;
1796
1797 if (!vq->private_data)
1798 return 0;
1799
1800 vhost_init_is_le(vq);
1801
1802 r = vhost_update_used_flags(vq);
1803 if (r)
1804 goto err;
1805 vq->signalled_used_valid = false;
1806 if (!vq->iotlb &&
1807 !access_ok(VERIFY_READ, &vq->used->idx, sizeof vq->used->idx)) {
1808 r = -EFAULT;
1809 goto err;
1810 }
1811 r = vhost_get_used(vq, last_used_idx, &vq->used->idx);
1812 if (r) {
1813 vq_err(vq, "Can't access used idx at %p\n",
1814 &vq->used->idx);
1815 goto err;
1816 }
1817 vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx);
1818 return 0;
1819
1820 err:
1821 vq->is_le = is_le;
1822 return r;
1823 }
1824 EXPORT_SYMBOL_GPL(vhost_vq_init_access);
1825
1826 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
1827 struct iovec iov[], int iov_size, int access)
1828 {
1829 const struct vhost_umem_node *node;
1830 struct vhost_dev *dev = vq->dev;
1831 struct vhost_umem *umem = dev->iotlb ? dev->iotlb : dev->umem;
1832 struct iovec *_iov;
1833 u64 s = 0;
1834 int ret = 0;
1835
1836 while ((u64)len > s) {
1837 u64 size;
1838 if (unlikely(ret >= iov_size)) {
1839 ret = -ENOBUFS;
1840 break;
1841 }
1842
1843 node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
1844 addr, addr + len - 1);
1845 if (node == NULL || node->start > addr) {
1846 if (umem != dev->iotlb) {
1847 ret = -EFAULT;
1848 break;
1849 }
1850 ret = -EAGAIN;
1851 break;
1852 } else if (!(node->perm & access)) {
1853 ret = -EPERM;
1854 break;
1855 }
1856
1857 _iov = iov + ret;
1858 size = node->size - addr + node->start;
1859 _iov->iov_len = min((u64)len - s, size);
1860 _iov->iov_base = (void __user *)(unsigned long)
1861 (node->userspace_addr + addr - node->start);
1862 s += size;
1863 addr += size;
1864 ++ret;
1865 }
1866
1867 if (ret == -EAGAIN)
1868 vhost_iotlb_miss(vq, addr, access);
1869 return ret;
1870 }
1871
1872 /* Each buffer in the virtqueues is actually a chain of descriptors. This
1873 * function returns the next descriptor in the chain,
1874 * or -1U if we're at the end. */
1875 static unsigned next_desc(struct vhost_virtqueue *vq, struct vring_desc *desc)
1876 {
1877 unsigned int next;
1878
1879 /* If this descriptor says it doesn't chain, we're done. */
1880 if (!(desc->flags & cpu_to_vhost16(vq, VRING_DESC_F_NEXT)))
1881 return -1U;
1882
1883 /* Check they're not leading us off end of descriptors. */
1884 next = vhost16_to_cpu(vq, desc->next);
1885 /* Make sure compiler knows to grab that: we don't want it changing! */
1886 /* We will use the result as an index in an array, so most
1887 * architectures only need a compiler barrier here. */
1888 read_barrier_depends();
1889
1890 return next;
1891 }
1892
1893 static int get_indirect(struct vhost_virtqueue *vq,
1894 struct iovec iov[], unsigned int iov_size,
1895 unsigned int *out_num, unsigned int *in_num,
1896 struct vhost_log *log, unsigned int *log_num,
1897 struct vring_desc *indirect)
1898 {
1899 struct vring_desc desc;
1900 unsigned int i = 0, count, found = 0;
1901 u32 len = vhost32_to_cpu(vq, indirect->len);
1902 struct iov_iter from;
1903 int ret, access;
1904
1905 /* Sanity check */
1906 if (unlikely(len % sizeof desc)) {
1907 vq_err(vq, "Invalid length in indirect descriptor: "
1908 "len 0x%llx not multiple of 0x%zx\n",
1909 (unsigned long long)len,
1910 sizeof desc);
1911 return -EINVAL;
1912 }
1913
1914 ret = translate_desc(vq, vhost64_to_cpu(vq, indirect->addr), len, vq->indirect,
1915 UIO_MAXIOV, VHOST_ACCESS_RO);
1916 if (unlikely(ret < 0)) {
1917 if (ret != -EAGAIN)
1918 vq_err(vq, "Translation failure %d in indirect.\n", ret);
1919 return ret;
1920 }
1921 iov_iter_init(&from, READ, vq->indirect, ret, len);
1922
1923 /* We will use the result as an address to read from, so most
1924 * architectures only need a compiler barrier here. */
1925 read_barrier_depends();
1926
1927 count = len / sizeof desc;
1928 /* Buffers are chained via a 16 bit next field, so
1929 * we can have at most 2^16 of these. */
1930 if (unlikely(count > USHRT_MAX + 1)) {
1931 vq_err(vq, "Indirect buffer length too big: %d\n",
1932 indirect->len);
1933 return -E2BIG;
1934 }
1935
1936 do {
1937 unsigned iov_count = *in_num + *out_num;
1938 if (unlikely(++found > count)) {
1939 vq_err(vq, "Loop detected: last one at %u "
1940 "indirect size %u\n",
1941 i, count);
1942 return -EINVAL;
1943 }
1944 if (unlikely(!copy_from_iter_full(&desc, sizeof(desc), &from))) {
1945 vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
1946 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
1947 return -EINVAL;
1948 }
1949 if (unlikely(desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT))) {
1950 vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n",
1951 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
1952 return -EINVAL;
1953 }
1954
1955 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
1956 access = VHOST_ACCESS_WO;
1957 else
1958 access = VHOST_ACCESS_RO;
1959
1960 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
1961 vhost32_to_cpu(vq, desc.len), iov + iov_count,
1962 iov_size - iov_count, access);
1963 if (unlikely(ret < 0)) {
1964 if (ret != -EAGAIN)
1965 vq_err(vq, "Translation failure %d indirect idx %d\n",
1966 ret, i);
1967 return ret;
1968 }
1969 /* If this is an input descriptor, increment that count. */
1970 if (access == VHOST_ACCESS_WO) {
1971 *in_num += ret;
1972 if (unlikely(log)) {
1973 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
1974 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
1975 ++*log_num;
1976 }
1977 } else {
1978 /* If it's an output descriptor, they're all supposed
1979 * to come before any input descriptors. */
1980 if (unlikely(*in_num)) {
1981 vq_err(vq, "Indirect descriptor "
1982 "has out after in: idx %d\n", i);
1983 return -EINVAL;
1984 }
1985 *out_num += ret;
1986 }
1987 } while ((i = next_desc(vq, &desc)) != -1);
1988 return 0;
1989 }
1990
1991 /* This looks in the virtqueue and for the first available buffer, and converts
1992 * it to an iovec for convenient access. Since descriptors consist of some
1993 * number of output then some number of input descriptors, it's actually two
1994 * iovecs, but we pack them into one and note how many of each there were.
1995 *
1996 * This function returns the descriptor number found, or vq->num (which is
1997 * never a valid descriptor number) if none was found. A negative code is
1998 * returned on error. */
1999 int vhost_get_vq_desc(struct vhost_virtqueue *vq,
2000 struct iovec iov[], unsigned int iov_size,
2001 unsigned int *out_num, unsigned int *in_num,
2002 struct vhost_log *log, unsigned int *log_num)
2003 {
2004 struct vring_desc desc;
2005 unsigned int i, head, found = 0;
2006 u16 last_avail_idx;
2007 __virtio16 avail_idx;
2008 __virtio16 ring_head;
2009 int ret, access;
2010
2011 /* Check it isn't doing very strange things with descriptor numbers. */
2012 last_avail_idx = vq->last_avail_idx;
2013
2014 if (vq->avail_idx == vq->last_avail_idx) {
2015 if (unlikely(vhost_get_avail(vq, avail_idx, &vq->avail->idx))) {
2016 vq_err(vq, "Failed to access avail idx at %p\n",
2017 &vq->avail->idx);
2018 return -EFAULT;
2019 }
2020 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2021
2022 if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) {
2023 vq_err(vq, "Guest moved used index from %u to %u",
2024 last_avail_idx, vq->avail_idx);
2025 return -EFAULT;
2026 }
2027
2028 /* If there's nothing new since last we looked, return
2029 * invalid.
2030 */
2031 if (vq->avail_idx == last_avail_idx)
2032 return vq->num;
2033
2034 /* Only get avail ring entries after they have been
2035 * exposed by guest.
2036 */
2037 smp_rmb();
2038 }
2039
2040 /* Grab the next descriptor number they're advertising, and increment
2041 * the index we've seen. */
2042 if (unlikely(vhost_get_avail(vq, ring_head,
2043 &vq->avail->ring[last_avail_idx & (vq->num - 1)]))) {
2044 vq_err(vq, "Failed to read head: idx %d address %p\n",
2045 last_avail_idx,
2046 &vq->avail->ring[last_avail_idx % vq->num]);
2047 return -EFAULT;
2048 }
2049
2050 head = vhost16_to_cpu(vq, ring_head);
2051
2052 /* If their number is silly, that's an error. */
2053 if (unlikely(head >= vq->num)) {
2054 vq_err(vq, "Guest says index %u > %u is available",
2055 head, vq->num);
2056 return -EINVAL;
2057 }
2058
2059 /* When we start there are none of either input nor output. */
2060 *out_num = *in_num = 0;
2061 if (unlikely(log))
2062 *log_num = 0;
2063
2064 i = head;
2065 do {
2066 unsigned iov_count = *in_num + *out_num;
2067 if (unlikely(i >= vq->num)) {
2068 vq_err(vq, "Desc index is %u > %u, head = %u",
2069 i, vq->num, head);
2070 return -EINVAL;
2071 }
2072 if (unlikely(++found > vq->num)) {
2073 vq_err(vq, "Loop detected: last one at %u "
2074 "vq size %u head %u\n",
2075 i, vq->num, head);
2076 return -EINVAL;
2077 }
2078 ret = vhost_copy_from_user(vq, &desc, vq->desc + i,
2079 sizeof desc);
2080 if (unlikely(ret)) {
2081 vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
2082 i, vq->desc + i);
2083 return -EFAULT;
2084 }
2085 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT)) {
2086 ret = get_indirect(vq, iov, iov_size,
2087 out_num, in_num,
2088 log, log_num, &desc);
2089 if (unlikely(ret < 0)) {
2090 if (ret != -EAGAIN)
2091 vq_err(vq, "Failure detected "
2092 "in indirect descriptor at idx %d\n", i);
2093 return ret;
2094 }
2095 continue;
2096 }
2097
2098 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
2099 access = VHOST_ACCESS_WO;
2100 else
2101 access = VHOST_ACCESS_RO;
2102 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
2103 vhost32_to_cpu(vq, desc.len), iov + iov_count,
2104 iov_size - iov_count, access);
2105 if (unlikely(ret < 0)) {
2106 if (ret != -EAGAIN)
2107 vq_err(vq, "Translation failure %d descriptor idx %d\n",
2108 ret, i);
2109 return ret;
2110 }
2111 if (access == VHOST_ACCESS_WO) {
2112 /* If this is an input descriptor,
2113 * increment that count. */
2114 *in_num += ret;
2115 if (unlikely(log)) {
2116 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
2117 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
2118 ++*log_num;
2119 }
2120 } else {
2121 /* If it's an output descriptor, they're all supposed
2122 * to come before any input descriptors. */
2123 if (unlikely(*in_num)) {
2124 vq_err(vq, "Descriptor has out after in: "
2125 "idx %d\n", i);
2126 return -EINVAL;
2127 }
2128 *out_num += ret;
2129 }
2130 } while ((i = next_desc(vq, &desc)) != -1);
2131
2132 /* On success, increment avail index. */
2133 vq->last_avail_idx++;
2134
2135 /* Assume notifications from guest are disabled at this point,
2136 * if they aren't we would need to update avail_event index. */
2137 BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY));
2138 return head;
2139 }
2140 EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
2141
2142 /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
2143 void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n)
2144 {
2145 vq->last_avail_idx -= n;
2146 }
2147 EXPORT_SYMBOL_GPL(vhost_discard_vq_desc);
2148
2149 /* After we've used one of their buffers, we tell them about it. We'll then
2150 * want to notify the guest, using eventfd. */
2151 int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
2152 {
2153 struct vring_used_elem heads = {
2154 cpu_to_vhost32(vq, head),
2155 cpu_to_vhost32(vq, len)
2156 };
2157
2158 return vhost_add_used_n(vq, &heads, 1);
2159 }
2160 EXPORT_SYMBOL_GPL(vhost_add_used);
2161
2162 static int __vhost_add_used_n(struct vhost_virtqueue *vq,
2163 struct vring_used_elem *heads,
2164 unsigned count)
2165 {
2166 struct vring_used_elem __user *used;
2167 u16 old, new;
2168 int start;
2169
2170 start = vq->last_used_idx & (vq->num - 1);
2171 used = vq->used->ring + start;
2172 if (count == 1) {
2173 if (vhost_put_user(vq, heads[0].id, &used->id)) {
2174 vq_err(vq, "Failed to write used id");
2175 return -EFAULT;
2176 }
2177 if (vhost_put_user(vq, heads[0].len, &used->len)) {
2178 vq_err(vq, "Failed to write used len");
2179 return -EFAULT;
2180 }
2181 } else if (vhost_copy_to_user(vq, used, heads, count * sizeof *used)) {
2182 vq_err(vq, "Failed to write used");
2183 return -EFAULT;
2184 }
2185 if (unlikely(vq->log_used)) {
2186 /* Make sure data is seen before log. */
2187 smp_wmb();
2188 /* Log used ring entry write. */
2189 log_write(vq->log_base,
2190 vq->log_addr +
2191 ((void __user *)used - (void __user *)vq->used),
2192 count * sizeof *used);
2193 }
2194 old = vq->last_used_idx;
2195 new = (vq->last_used_idx += count);
2196 /* If the driver never bothers to signal in a very long while,
2197 * used index might wrap around. If that happens, invalidate
2198 * signalled_used index we stored. TODO: make sure driver
2199 * signals at least once in 2^16 and remove this. */
2200 if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old)))
2201 vq->signalled_used_valid = false;
2202 return 0;
2203 }
2204
2205 /* After we've used one of their buffers, we tell them about it. We'll then
2206 * want to notify the guest, using eventfd. */
2207 int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
2208 unsigned count)
2209 {
2210 int start, n, r;
2211
2212 start = vq->last_used_idx & (vq->num - 1);
2213 n = vq->num - start;
2214 if (n < count) {
2215 r = __vhost_add_used_n(vq, heads, n);
2216 if (r < 0)
2217 return r;
2218 heads += n;
2219 count -= n;
2220 }
2221 r = __vhost_add_used_n(vq, heads, count);
2222
2223 /* Make sure buffer is written before we update index. */
2224 smp_wmb();
2225 if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx),
2226 &vq->used->idx)) {
2227 vq_err(vq, "Failed to increment used idx");
2228 return -EFAULT;
2229 }
2230 if (unlikely(vq->log_used)) {
2231 /* Log used index update. */
2232 log_write(vq->log_base,
2233 vq->log_addr + offsetof(struct vring_used, idx),
2234 sizeof vq->used->idx);
2235 if (vq->log_ctx)
2236 eventfd_signal(vq->log_ctx, 1);
2237 }
2238 return r;
2239 }
2240 EXPORT_SYMBOL_GPL(vhost_add_used_n);
2241
2242 static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2243 {
2244 __u16 old, new;
2245 __virtio16 event;
2246 bool v;
2247 /* Flush out used index updates. This is paired
2248 * with the barrier that the Guest executes when enabling
2249 * interrupts. */
2250 smp_mb();
2251
2252 if (vhost_has_feature(vq, VIRTIO_F_NOTIFY_ON_EMPTY) &&
2253 unlikely(vq->avail_idx == vq->last_avail_idx))
2254 return true;
2255
2256 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2257 __virtio16 flags;
2258 if (vhost_get_avail(vq, flags, &vq->avail->flags)) {
2259 vq_err(vq, "Failed to get flags");
2260 return true;
2261 }
2262 return !(flags & cpu_to_vhost16(vq, VRING_AVAIL_F_NO_INTERRUPT));
2263 }
2264 old = vq->signalled_used;
2265 v = vq->signalled_used_valid;
2266 new = vq->signalled_used = vq->last_used_idx;
2267 vq->signalled_used_valid = true;
2268
2269 if (unlikely(!v))
2270 return true;
2271
2272 if (vhost_get_avail(vq, event, vhost_used_event(vq))) {
2273 vq_err(vq, "Failed to get used event idx");
2274 return true;
2275 }
2276 return vring_need_event(vhost16_to_cpu(vq, event), new, old);
2277 }
2278
2279 /* This actually signals the guest, using eventfd. */
2280 void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2281 {
2282 /* Signal the Guest tell them we used something up. */
2283 if (vq->call_ctx && vhost_notify(dev, vq))
2284 eventfd_signal(vq->call_ctx, 1);
2285 }
2286 EXPORT_SYMBOL_GPL(vhost_signal);
2287
2288 /* And here's the combo meal deal. Supersize me! */
2289 void vhost_add_used_and_signal(struct vhost_dev *dev,
2290 struct vhost_virtqueue *vq,
2291 unsigned int head, int len)
2292 {
2293 vhost_add_used(vq, head, len);
2294 vhost_signal(dev, vq);
2295 }
2296 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal);
2297
2298 /* multi-buffer version of vhost_add_used_and_signal */
2299 void vhost_add_used_and_signal_n(struct vhost_dev *dev,
2300 struct vhost_virtqueue *vq,
2301 struct vring_used_elem *heads, unsigned count)
2302 {
2303 vhost_add_used_n(vq, heads, count);
2304 vhost_signal(dev, vq);
2305 }
2306 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
2307
2308 /* return true if we're sure that avaiable ring is empty */
2309 bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2310 {
2311 __virtio16 avail_idx;
2312 int r;
2313
2314 if (vq->avail_idx != vq->last_avail_idx)
2315 return false;
2316
2317 r = vhost_get_avail(vq, avail_idx, &vq->avail->idx);
2318 if (unlikely(r))
2319 return false;
2320 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2321
2322 return vq->avail_idx == vq->last_avail_idx;
2323 }
2324 EXPORT_SYMBOL_GPL(vhost_vq_avail_empty);
2325
2326 /* OK, now we need to know about added descriptors. */
2327 bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2328 {
2329 __virtio16 avail_idx;
2330 int r;
2331
2332 if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
2333 return false;
2334 vq->used_flags &= ~VRING_USED_F_NO_NOTIFY;
2335 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2336 r = vhost_update_used_flags(vq);
2337 if (r) {
2338 vq_err(vq, "Failed to enable notification at %p: %d\n",
2339 &vq->used->flags, r);
2340 return false;
2341 }
2342 } else {
2343 r = vhost_update_avail_event(vq, vq->avail_idx);
2344 if (r) {
2345 vq_err(vq, "Failed to update avail event index at %p: %d\n",
2346 vhost_avail_event(vq), r);
2347 return false;
2348 }
2349 }
2350 /* They could have slipped one in as we were doing that: make
2351 * sure it's written, then check again. */
2352 smp_mb();
2353 r = vhost_get_avail(vq, avail_idx, &vq->avail->idx);
2354 if (r) {
2355 vq_err(vq, "Failed to check avail idx at %p: %d\n",
2356 &vq->avail->idx, r);
2357 return false;
2358 }
2359
2360 return vhost16_to_cpu(vq, avail_idx) != vq->avail_idx;
2361 }
2362 EXPORT_SYMBOL_GPL(vhost_enable_notify);
2363
2364 /* We don't need to be notified again. */
2365 void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2366 {
2367 int r;
2368
2369 if (vq->used_flags & VRING_USED_F_NO_NOTIFY)
2370 return;
2371 vq->used_flags |= VRING_USED_F_NO_NOTIFY;
2372 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2373 r = vhost_update_used_flags(vq);
2374 if (r)
2375 vq_err(vq, "Failed to enable notification at %p: %d\n",
2376 &vq->used->flags, r);
2377 }
2378 }
2379 EXPORT_SYMBOL_GPL(vhost_disable_notify);
2380
2381 /* Create a new message. */
2382 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type)
2383 {
2384 struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL);
2385 if (!node)
2386 return NULL;
2387 node->vq = vq;
2388 node->msg.type = type;
2389 return node;
2390 }
2391 EXPORT_SYMBOL_GPL(vhost_new_msg);
2392
2393 void vhost_enqueue_msg(struct vhost_dev *dev, struct list_head *head,
2394 struct vhost_msg_node *node)
2395 {
2396 spin_lock(&dev->iotlb_lock);
2397 list_add_tail(&node->node, head);
2398 spin_unlock(&dev->iotlb_lock);
2399
2400 wake_up_interruptible_poll(&dev->wait, POLLIN | POLLRDNORM);
2401 }
2402 EXPORT_SYMBOL_GPL(vhost_enqueue_msg);
2403
2404 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
2405 struct list_head *head)
2406 {
2407 struct vhost_msg_node *node = NULL;
2408
2409 spin_lock(&dev->iotlb_lock);
2410 if (!list_empty(head)) {
2411 node = list_first_entry(head, struct vhost_msg_node,
2412 node);
2413 list_del(&node->node);
2414 }
2415 spin_unlock(&dev->iotlb_lock);
2416
2417 return node;
2418 }
2419 EXPORT_SYMBOL_GPL(vhost_dequeue_msg);
2420
2421
2422 static int __init vhost_init(void)
2423 {
2424 return 0;
2425 }
2426
2427 static void __exit vhost_exit(void)
2428 {
2429 }
2430
2431 module_init(vhost_init);
2432 module_exit(vhost_exit);
2433
2434 MODULE_VERSION("0.0.1");
2435 MODULE_LICENSE("GPL v2");
2436 MODULE_AUTHOR("Michael S. Tsirkin");
2437 MODULE_DESCRIPTION("Host kernel accelerator for virtio");
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