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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->last_used_event = 0;
312 vq->avail_idx = 0;
313 vq->last_used_idx = 0;
314 vq->signalled_used = 0;
315 vq->signalled_used_valid = false;
316 vq->used_flags = 0;
317 vq->log_used = false;
318 vq->log_addr = -1ull;
319 vq->private_data = NULL;
320 vq->acked_features = 0;
321 vq->log_base = NULL;
322 vq->error_ctx = NULL;
323 vq->error = NULL;
324 vq->kick = NULL;
325 vq->call_ctx = NULL;
326 vq->call = NULL;
327 vq->log_ctx = NULL;
328 vhost_reset_is_le(vq);
329 vhost_disable_cross_endian(vq);
330 vq->busyloop_timeout = 0;
331 vq->umem = NULL;
332 vq->iotlb = NULL;
333 __vhost_vq_meta_reset(vq);
334 }
335
336 static int vhost_worker(void *data)
337 {
338 struct vhost_dev *dev = data;
339 struct vhost_work *work, *work_next;
340 struct llist_node *node;
341 mm_segment_t oldfs = get_fs();
342
343 set_fs(USER_DS);
344 use_mm(dev->mm);
345
346 for (;;) {
347 /* mb paired w/ kthread_stop */
348 set_current_state(TASK_INTERRUPTIBLE);
349
350 if (kthread_should_stop()) {
351 __set_current_state(TASK_RUNNING);
352 break;
353 }
354
355 node = llist_del_all(&dev->work_list);
356 if (!node)
357 schedule();
358
359 node = llist_reverse_order(node);
360 /* make sure flag is seen after deletion */
361 smp_wmb();
362 llist_for_each_entry_safe(work, work_next, node, node) {
363 clear_bit(VHOST_WORK_QUEUED, &work->flags);
364 __set_current_state(TASK_RUNNING);
365 work->fn(work);
366 if (need_resched())
367 schedule();
368 }
369 }
370 unuse_mm(dev->mm);
371 set_fs(oldfs);
372 return 0;
373 }
374
375 static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq)
376 {
377 kfree(vq->indirect);
378 vq->indirect = NULL;
379 kfree(vq->log);
380 vq->log = NULL;
381 kfree(vq->heads);
382 vq->heads = NULL;
383 }
384
385 /* Helper to allocate iovec buffers for all vqs. */
386 static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
387 {
388 struct vhost_virtqueue *vq;
389 int i;
390
391 for (i = 0; i < dev->nvqs; ++i) {
392 vq = dev->vqs[i];
393 vq->indirect = kmalloc(sizeof *vq->indirect * UIO_MAXIOV,
394 GFP_KERNEL);
395 vq->log = kmalloc(sizeof *vq->log * UIO_MAXIOV, GFP_KERNEL);
396 vq->heads = kmalloc(sizeof *vq->heads * UIO_MAXIOV, GFP_KERNEL);
397 if (!vq->indirect || !vq->log || !vq->heads)
398 goto err_nomem;
399 }
400 return 0;
401
402 err_nomem:
403 for (; i >= 0; --i)
404 vhost_vq_free_iovecs(dev->vqs[i]);
405 return -ENOMEM;
406 }
407
408 static void vhost_dev_free_iovecs(struct vhost_dev *dev)
409 {
410 int i;
411
412 for (i = 0; i < dev->nvqs; ++i)
413 vhost_vq_free_iovecs(dev->vqs[i]);
414 }
415
416 void vhost_dev_init(struct vhost_dev *dev,
417 struct vhost_virtqueue **vqs, int nvqs)
418 {
419 struct vhost_virtqueue *vq;
420 int i;
421
422 dev->vqs = vqs;
423 dev->nvqs = nvqs;
424 mutex_init(&dev->mutex);
425 dev->log_ctx = NULL;
426 dev->log_file = NULL;
427 dev->umem = NULL;
428 dev->iotlb = NULL;
429 dev->mm = NULL;
430 dev->worker = NULL;
431 init_llist_head(&dev->work_list);
432 init_waitqueue_head(&dev->wait);
433 INIT_LIST_HEAD(&dev->read_list);
434 INIT_LIST_HEAD(&dev->pending_list);
435 spin_lock_init(&dev->iotlb_lock);
436
437
438 for (i = 0; i < dev->nvqs; ++i) {
439 vq = dev->vqs[i];
440 vq->log = NULL;
441 vq->indirect = NULL;
442 vq->heads = NULL;
443 vq->dev = dev;
444 mutex_init(&vq->mutex);
445 vhost_vq_reset(dev, vq);
446 if (vq->handle_kick)
447 vhost_poll_init(&vq->poll, vq->handle_kick,
448 POLLIN, dev);
449 }
450 }
451 EXPORT_SYMBOL_GPL(vhost_dev_init);
452
453 /* Caller should have device mutex */
454 long vhost_dev_check_owner(struct vhost_dev *dev)
455 {
456 /* Are you the owner? If not, I don't think you mean to do that */
457 return dev->mm == current->mm ? 0 : -EPERM;
458 }
459 EXPORT_SYMBOL_GPL(vhost_dev_check_owner);
460
461 struct vhost_attach_cgroups_struct {
462 struct vhost_work work;
463 struct task_struct *owner;
464 int ret;
465 };
466
467 static void vhost_attach_cgroups_work(struct vhost_work *work)
468 {
469 struct vhost_attach_cgroups_struct *s;
470
471 s = container_of(work, struct vhost_attach_cgroups_struct, work);
472 s->ret = cgroup_attach_task_all(s->owner, current);
473 }
474
475 static int vhost_attach_cgroups(struct vhost_dev *dev)
476 {
477 struct vhost_attach_cgroups_struct attach;
478
479 attach.owner = current;
480 vhost_work_init(&attach.work, vhost_attach_cgroups_work);
481 vhost_work_queue(dev, &attach.work);
482 vhost_work_flush(dev, &attach.work);
483 return attach.ret;
484 }
485
486 /* Caller should have device mutex */
487 bool vhost_dev_has_owner(struct vhost_dev *dev)
488 {
489 return dev->mm;
490 }
491 EXPORT_SYMBOL_GPL(vhost_dev_has_owner);
492
493 /* Caller should have device mutex */
494 long vhost_dev_set_owner(struct vhost_dev *dev)
495 {
496 struct task_struct *worker;
497 int err;
498
499 /* Is there an owner already? */
500 if (vhost_dev_has_owner(dev)) {
501 err = -EBUSY;
502 goto err_mm;
503 }
504
505 /* No owner, become one */
506 dev->mm = get_task_mm(current);
507 worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid);
508 if (IS_ERR(worker)) {
509 err = PTR_ERR(worker);
510 goto err_worker;
511 }
512
513 dev->worker = worker;
514 wake_up_process(worker); /* avoid contributing to loadavg */
515
516 err = vhost_attach_cgroups(dev);
517 if (err)
518 goto err_cgroup;
519
520 err = vhost_dev_alloc_iovecs(dev);
521 if (err)
522 goto err_cgroup;
523
524 return 0;
525 err_cgroup:
526 kthread_stop(worker);
527 dev->worker = NULL;
528 err_worker:
529 if (dev->mm)
530 mmput(dev->mm);
531 dev->mm = NULL;
532 err_mm:
533 return err;
534 }
535 EXPORT_SYMBOL_GPL(vhost_dev_set_owner);
536
537 struct vhost_umem *vhost_dev_reset_owner_prepare(void)
538 {
539 return kvzalloc(sizeof(struct vhost_umem), GFP_KERNEL);
540 }
541 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare);
542
543 /* Caller should have device mutex */
544 void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_umem *umem)
545 {
546 int i;
547
548 vhost_dev_cleanup(dev, true);
549
550 /* Restore memory to default empty mapping. */
551 INIT_LIST_HEAD(&umem->umem_list);
552 dev->umem = umem;
553 /* We don't need VQ locks below since vhost_dev_cleanup makes sure
554 * VQs aren't running.
555 */
556 for (i = 0; i < dev->nvqs; ++i)
557 dev->vqs[i]->umem = umem;
558 }
559 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner);
560
561 void vhost_dev_stop(struct vhost_dev *dev)
562 {
563 int i;
564
565 for (i = 0; i < dev->nvqs; ++i) {
566 if (dev->vqs[i]->kick && dev->vqs[i]->handle_kick) {
567 vhost_poll_stop(&dev->vqs[i]->poll);
568 vhost_poll_flush(&dev->vqs[i]->poll);
569 }
570 }
571 }
572 EXPORT_SYMBOL_GPL(vhost_dev_stop);
573
574 static void vhost_umem_free(struct vhost_umem *umem,
575 struct vhost_umem_node *node)
576 {
577 vhost_umem_interval_tree_remove(node, &umem->umem_tree);
578 list_del(&node->link);
579 kfree(node);
580 umem->numem--;
581 }
582
583 static void vhost_umem_clean(struct vhost_umem *umem)
584 {
585 struct vhost_umem_node *node, *tmp;
586
587 if (!umem)
588 return;
589
590 list_for_each_entry_safe(node, tmp, &umem->umem_list, link)
591 vhost_umem_free(umem, node);
592
593 kvfree(umem);
594 }
595
596 static void vhost_clear_msg(struct vhost_dev *dev)
597 {
598 struct vhost_msg_node *node, *n;
599
600 spin_lock(&dev->iotlb_lock);
601
602 list_for_each_entry_safe(node, n, &dev->read_list, node) {
603 list_del(&node->node);
604 kfree(node);
605 }
606
607 list_for_each_entry_safe(node, n, &dev->pending_list, node) {
608 list_del(&node->node);
609 kfree(node);
610 }
611
612 spin_unlock(&dev->iotlb_lock);
613 }
614
615 /* Caller should have device mutex if and only if locked is set */
616 void vhost_dev_cleanup(struct vhost_dev *dev, bool locked)
617 {
618 int i;
619
620 for (i = 0; i < dev->nvqs; ++i) {
621 if (dev->vqs[i]->error_ctx)
622 eventfd_ctx_put(dev->vqs[i]->error_ctx);
623 if (dev->vqs[i]->error)
624 fput(dev->vqs[i]->error);
625 if (dev->vqs[i]->kick)
626 fput(dev->vqs[i]->kick);
627 if (dev->vqs[i]->call_ctx)
628 eventfd_ctx_put(dev->vqs[i]->call_ctx);
629 if (dev->vqs[i]->call)
630 fput(dev->vqs[i]->call);
631 vhost_vq_reset(dev, dev->vqs[i]);
632 }
633 vhost_dev_free_iovecs(dev);
634 if (dev->log_ctx)
635 eventfd_ctx_put(dev->log_ctx);
636 dev->log_ctx = NULL;
637 if (dev->log_file)
638 fput(dev->log_file);
639 dev->log_file = NULL;
640 /* No one will access memory at this point */
641 vhost_umem_clean(dev->umem);
642 dev->umem = NULL;
643 vhost_umem_clean(dev->iotlb);
644 dev->iotlb = NULL;
645 vhost_clear_msg(dev);
646 wake_up_interruptible_poll(&dev->wait, POLLIN | POLLRDNORM);
647 WARN_ON(!llist_empty(&dev->work_list));
648 if (dev->worker) {
649 kthread_stop(dev->worker);
650 dev->worker = NULL;
651 }
652 if (dev->mm)
653 mmput(dev->mm);
654 dev->mm = NULL;
655 }
656 EXPORT_SYMBOL_GPL(vhost_dev_cleanup);
657
658 static int log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
659 {
660 u64 a = addr / VHOST_PAGE_SIZE / 8;
661
662 /* Make sure 64 bit math will not overflow. */
663 if (a > ULONG_MAX - (unsigned long)log_base ||
664 a + (unsigned long)log_base > ULONG_MAX)
665 return 0;
666
667 return access_ok(VERIFY_WRITE, log_base + a,
668 (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8);
669 }
670
671 static bool vhost_overflow(u64 uaddr, u64 size)
672 {
673 /* Make sure 64 bit math will not overflow. */
674 return uaddr > ULONG_MAX || size > ULONG_MAX || uaddr > ULONG_MAX - size;
675 }
676
677 /* Caller should have vq mutex and device mutex. */
678 static int vq_memory_access_ok(void __user *log_base, struct vhost_umem *umem,
679 int log_all)
680 {
681 struct vhost_umem_node *node;
682
683 if (!umem)
684 return 0;
685
686 list_for_each_entry(node, &umem->umem_list, link) {
687 unsigned long a = node->userspace_addr;
688
689 if (vhost_overflow(node->userspace_addr, node->size))
690 return 0;
691
692
693 if (!access_ok(VERIFY_WRITE, (void __user *)a,
694 node->size))
695 return 0;
696 else if (log_all && !log_access_ok(log_base,
697 node->start,
698 node->size))
699 return 0;
700 }
701 return 1;
702 }
703
704 static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq,
705 u64 addr, unsigned int size,
706 int type)
707 {
708 const struct vhost_umem_node *node = vq->meta_iotlb[type];
709
710 if (!node)
711 return NULL;
712
713 return (void *)(uintptr_t)(node->userspace_addr + addr - node->start);
714 }
715
716 /* Can we switch to this memory table? */
717 /* Caller should have device mutex but not vq mutex */
718 static int memory_access_ok(struct vhost_dev *d, struct vhost_umem *umem,
719 int log_all)
720 {
721 int i;
722
723 for (i = 0; i < d->nvqs; ++i) {
724 int ok;
725 bool log;
726
727 mutex_lock(&d->vqs[i]->mutex);
728 log = log_all || vhost_has_feature(d->vqs[i], VHOST_F_LOG_ALL);
729 /* If ring is inactive, will check when it's enabled. */
730 if (d->vqs[i]->private_data)
731 ok = vq_memory_access_ok(d->vqs[i]->log_base,
732 umem, log);
733 else
734 ok = 1;
735 mutex_unlock(&d->vqs[i]->mutex);
736 if (!ok)
737 return 0;
738 }
739 return 1;
740 }
741
742 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
743 struct iovec iov[], int iov_size, int access);
744
745 static int vhost_copy_to_user(struct vhost_virtqueue *vq, void __user *to,
746 const void *from, unsigned size)
747 {
748 int ret;
749
750 if (!vq->iotlb)
751 return __copy_to_user(to, from, size);
752 else {
753 /* This function should be called after iotlb
754 * prefetch, which means we're sure that all vq
755 * could be access through iotlb. So -EAGAIN should
756 * not happen in this case.
757 */
758 struct iov_iter t;
759 void __user *uaddr = vhost_vq_meta_fetch(vq,
760 (u64)(uintptr_t)to, size,
761 VHOST_ADDR_DESC);
762
763 if (uaddr)
764 return __copy_to_user(uaddr, from, size);
765
766 ret = translate_desc(vq, (u64)(uintptr_t)to, size, vq->iotlb_iov,
767 ARRAY_SIZE(vq->iotlb_iov),
768 VHOST_ACCESS_WO);
769 if (ret < 0)
770 goto out;
771 iov_iter_init(&t, WRITE, vq->iotlb_iov, ret, size);
772 ret = copy_to_iter(from, size, &t);
773 if (ret == size)
774 ret = 0;
775 }
776 out:
777 return ret;
778 }
779
780 static int vhost_copy_from_user(struct vhost_virtqueue *vq, void *to,
781 void __user *from, unsigned size)
782 {
783 int ret;
784
785 if (!vq->iotlb)
786 return __copy_from_user(to, from, size);
787 else {
788 /* This function should be called after iotlb
789 * prefetch, which means we're sure that vq
790 * could be access through iotlb. So -EAGAIN should
791 * not happen in this case.
792 */
793 void __user *uaddr = vhost_vq_meta_fetch(vq,
794 (u64)(uintptr_t)from, size,
795 VHOST_ADDR_DESC);
796 struct iov_iter f;
797
798 if (uaddr)
799 return __copy_from_user(to, uaddr, size);
800
801 ret = translate_desc(vq, (u64)(uintptr_t)from, size, vq->iotlb_iov,
802 ARRAY_SIZE(vq->iotlb_iov),
803 VHOST_ACCESS_RO);
804 if (ret < 0) {
805 vq_err(vq, "IOTLB translation failure: uaddr "
806 "%p size 0x%llx\n", from,
807 (unsigned long long) size);
808 goto out;
809 }
810 iov_iter_init(&f, READ, vq->iotlb_iov, ret, size);
811 ret = copy_from_iter(to, size, &f);
812 if (ret == size)
813 ret = 0;
814 }
815
816 out:
817 return ret;
818 }
819
820 static void __user *__vhost_get_user_slow(struct vhost_virtqueue *vq,
821 void __user *addr, unsigned int size,
822 int type)
823 {
824 int ret;
825
826 ret = translate_desc(vq, (u64)(uintptr_t)addr, size, vq->iotlb_iov,
827 ARRAY_SIZE(vq->iotlb_iov),
828 VHOST_ACCESS_RO);
829 if (ret < 0) {
830 vq_err(vq, "IOTLB translation failure: uaddr "
831 "%p size 0x%llx\n", addr,
832 (unsigned long long) size);
833 return NULL;
834 }
835
836 if (ret != 1 || vq->iotlb_iov[0].iov_len != size) {
837 vq_err(vq, "Non atomic userspace memory access: uaddr "
838 "%p size 0x%llx\n", addr,
839 (unsigned long long) size);
840 return NULL;
841 }
842
843 return vq->iotlb_iov[0].iov_base;
844 }
845
846 /* This function should be called after iotlb
847 * prefetch, which means we're sure that vq
848 * could be access through iotlb. So -EAGAIN should
849 * not happen in this case.
850 */
851 static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq,
852 void *addr, unsigned int size,
853 int type)
854 {
855 void __user *uaddr = vhost_vq_meta_fetch(vq,
856 (u64)(uintptr_t)addr, size, type);
857 if (uaddr)
858 return uaddr;
859
860 return __vhost_get_user_slow(vq, addr, size, type);
861 }
862
863 #define vhost_put_user(vq, x, ptr) \
864 ({ \
865 int ret = -EFAULT; \
866 if (!vq->iotlb) { \
867 ret = __put_user(x, ptr); \
868 } else { \
869 __typeof__(ptr) to = \
870 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
871 sizeof(*ptr), VHOST_ADDR_USED); \
872 if (to != NULL) \
873 ret = __put_user(x, to); \
874 else \
875 ret = -EFAULT; \
876 } \
877 ret; \
878 })
879
880 #define vhost_get_user(vq, x, ptr, type) \
881 ({ \
882 int ret; \
883 if (!vq->iotlb) { \
884 ret = __get_user(x, ptr); \
885 } else { \
886 __typeof__(ptr) from = \
887 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
888 sizeof(*ptr), \
889 type); \
890 if (from != NULL) \
891 ret = __get_user(x, from); \
892 else \
893 ret = -EFAULT; \
894 } \
895 ret; \
896 })
897
898 #define vhost_get_avail(vq, x, ptr) \
899 vhost_get_user(vq, x, ptr, VHOST_ADDR_AVAIL)
900
901 #define vhost_get_used(vq, x, ptr) \
902 vhost_get_user(vq, x, ptr, VHOST_ADDR_USED)
903
904 static void vhost_dev_lock_vqs(struct vhost_dev *d)
905 {
906 int i = 0;
907 for (i = 0; i < d->nvqs; ++i)
908 mutex_lock(&d->vqs[i]->mutex);
909 }
910
911 static void vhost_dev_unlock_vqs(struct vhost_dev *d)
912 {
913 int i = 0;
914 for (i = 0; i < d->nvqs; ++i)
915 mutex_unlock(&d->vqs[i]->mutex);
916 }
917
918 static int vhost_new_umem_range(struct vhost_umem *umem,
919 u64 start, u64 size, u64 end,
920 u64 userspace_addr, int perm)
921 {
922 struct vhost_umem_node *tmp, *node = kmalloc(sizeof(*node), GFP_ATOMIC);
923
924 if (!node)
925 return -ENOMEM;
926
927 if (umem->numem == max_iotlb_entries) {
928 tmp = list_first_entry(&umem->umem_list, typeof(*tmp), link);
929 vhost_umem_free(umem, tmp);
930 }
931
932 node->start = start;
933 node->size = size;
934 node->last = end;
935 node->userspace_addr = userspace_addr;
936 node->perm = perm;
937 INIT_LIST_HEAD(&node->link);
938 list_add_tail(&node->link, &umem->umem_list);
939 vhost_umem_interval_tree_insert(node, &umem->umem_tree);
940 umem->numem++;
941
942 return 0;
943 }
944
945 static void vhost_del_umem_range(struct vhost_umem *umem,
946 u64 start, u64 end)
947 {
948 struct vhost_umem_node *node;
949
950 while ((node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
951 start, end)))
952 vhost_umem_free(umem, node);
953 }
954
955 static void vhost_iotlb_notify_vq(struct vhost_dev *d,
956 struct vhost_iotlb_msg *msg)
957 {
958 struct vhost_msg_node *node, *n;
959
960 spin_lock(&d->iotlb_lock);
961
962 list_for_each_entry_safe(node, n, &d->pending_list, node) {
963 struct vhost_iotlb_msg *vq_msg = &node->msg.iotlb;
964 if (msg->iova <= vq_msg->iova &&
965 msg->iova + msg->size - 1 > vq_msg->iova &&
966 vq_msg->type == VHOST_IOTLB_MISS) {
967 vhost_poll_queue(&node->vq->poll);
968 list_del(&node->node);
969 kfree(node);
970 }
971 }
972
973 spin_unlock(&d->iotlb_lock);
974 }
975
976 static int umem_access_ok(u64 uaddr, u64 size, int access)
977 {
978 unsigned long a = uaddr;
979
980 /* Make sure 64 bit math will not overflow. */
981 if (vhost_overflow(uaddr, size))
982 return -EFAULT;
983
984 if ((access & VHOST_ACCESS_RO) &&
985 !access_ok(VERIFY_READ, (void __user *)a, size))
986 return -EFAULT;
987 if ((access & VHOST_ACCESS_WO) &&
988 !access_ok(VERIFY_WRITE, (void __user *)a, size))
989 return -EFAULT;
990 return 0;
991 }
992
993 static int vhost_process_iotlb_msg(struct vhost_dev *dev,
994 struct vhost_iotlb_msg *msg)
995 {
996 int ret = 0;
997
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 vhost_vq_meta_reset(dev);
1020 vhost_del_umem_range(dev->iotlb, msg->iova,
1021 msg->iova + msg->size - 1);
1022 break;
1023 default:
1024 ret = -EINVAL;
1025 break;
1026 }
1027
1028 vhost_dev_unlock_vqs(dev);
1029 return ret;
1030 }
1031 ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
1032 struct iov_iter *from)
1033 {
1034 struct vhost_msg_node node;
1035 unsigned size = sizeof(struct vhost_msg);
1036 size_t ret;
1037 int err;
1038
1039 if (iov_iter_count(from) < size)
1040 return 0;
1041 ret = copy_from_iter(&node.msg, size, from);
1042 if (ret != size)
1043 goto done;
1044
1045 switch (node.msg.type) {
1046 case VHOST_IOTLB_MSG:
1047 err = vhost_process_iotlb_msg(dev, &node.msg.iotlb);
1048 if (err)
1049 ret = err;
1050 break;
1051 default:
1052 ret = -EINVAL;
1053 break;
1054 }
1055
1056 done:
1057 return ret;
1058 }
1059 EXPORT_SYMBOL(vhost_chr_write_iter);
1060
1061 unsigned int vhost_chr_poll(struct file *file, struct vhost_dev *dev,
1062 poll_table *wait)
1063 {
1064 unsigned int mask = 0;
1065
1066 poll_wait(file, &dev->wait, wait);
1067
1068 if (!list_empty(&dev->read_list))
1069 mask |= POLLIN | POLLRDNORM;
1070
1071 return mask;
1072 }
1073 EXPORT_SYMBOL(vhost_chr_poll);
1074
1075 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
1076 int noblock)
1077 {
1078 DEFINE_WAIT(wait);
1079 struct vhost_msg_node *node;
1080 ssize_t ret = 0;
1081 unsigned size = sizeof(struct vhost_msg);
1082
1083 if (iov_iter_count(to) < size)
1084 return 0;
1085
1086 while (1) {
1087 if (!noblock)
1088 prepare_to_wait(&dev->wait, &wait,
1089 TASK_INTERRUPTIBLE);
1090
1091 node = vhost_dequeue_msg(dev, &dev->read_list);
1092 if (node)
1093 break;
1094 if (noblock) {
1095 ret = -EAGAIN;
1096 break;
1097 }
1098 if (signal_pending(current)) {
1099 ret = -ERESTARTSYS;
1100 break;
1101 }
1102 if (!dev->iotlb) {
1103 ret = -EBADFD;
1104 break;
1105 }
1106
1107 schedule();
1108 }
1109
1110 if (!noblock)
1111 finish_wait(&dev->wait, &wait);
1112
1113 if (node) {
1114 ret = copy_to_iter(&node->msg, size, to);
1115
1116 if (ret != size || node->msg.type != VHOST_IOTLB_MISS) {
1117 kfree(node);
1118 return ret;
1119 }
1120
1121 vhost_enqueue_msg(dev, &dev->pending_list, node);
1122 }
1123
1124 return ret;
1125 }
1126 EXPORT_SYMBOL_GPL(vhost_chr_read_iter);
1127
1128 static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access)
1129 {
1130 struct vhost_dev *dev = vq->dev;
1131 struct vhost_msg_node *node;
1132 struct vhost_iotlb_msg *msg;
1133
1134 node = vhost_new_msg(vq, VHOST_IOTLB_MISS);
1135 if (!node)
1136 return -ENOMEM;
1137
1138 msg = &node->msg.iotlb;
1139 msg->type = VHOST_IOTLB_MISS;
1140 msg->iova = iova;
1141 msg->perm = access;
1142
1143 vhost_enqueue_msg(dev, &dev->read_list, node);
1144
1145 return 0;
1146 }
1147
1148 static int vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
1149 struct vring_desc __user *desc,
1150 struct vring_avail __user *avail,
1151 struct vring_used __user *used)
1152
1153 {
1154 size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
1155
1156 return access_ok(VERIFY_READ, desc, num * sizeof *desc) &&
1157 access_ok(VERIFY_READ, avail,
1158 sizeof *avail + num * sizeof *avail->ring + s) &&
1159 access_ok(VERIFY_WRITE, used,
1160 sizeof *used + num * sizeof *used->ring + s);
1161 }
1162
1163 static void vhost_vq_meta_update(struct vhost_virtqueue *vq,
1164 const struct vhost_umem_node *node,
1165 int type)
1166 {
1167 int access = (type == VHOST_ADDR_USED) ?
1168 VHOST_ACCESS_WO : VHOST_ACCESS_RO;
1169
1170 if (likely(node->perm & access))
1171 vq->meta_iotlb[type] = node;
1172 }
1173
1174 static int iotlb_access_ok(struct vhost_virtqueue *vq,
1175 int access, u64 addr, u64 len, int type)
1176 {
1177 const struct vhost_umem_node *node;
1178 struct vhost_umem *umem = vq->iotlb;
1179 u64 s = 0, size, orig_addr = addr;
1180
1181 if (vhost_vq_meta_fetch(vq, addr, len, type))
1182 return true;
1183
1184 while (len > s) {
1185 node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
1186 addr,
1187 addr + len - 1);
1188 if (node == NULL || node->start > addr) {
1189 vhost_iotlb_miss(vq, addr, access);
1190 return false;
1191 } else if (!(node->perm & access)) {
1192 /* Report the possible access violation by
1193 * request another translation from userspace.
1194 */
1195 return false;
1196 }
1197
1198 size = node->size - addr + node->start;
1199
1200 if (orig_addr == addr && size >= len)
1201 vhost_vq_meta_update(vq, node, type);
1202
1203 s += size;
1204 addr += size;
1205 }
1206
1207 return true;
1208 }
1209
1210 int vq_iotlb_prefetch(struct vhost_virtqueue *vq)
1211 {
1212 size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
1213 unsigned int num = vq->num;
1214
1215 if (!vq->iotlb)
1216 return 1;
1217
1218 return iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->desc,
1219 num * sizeof(*vq->desc), VHOST_ADDR_DESC) &&
1220 iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->avail,
1221 sizeof *vq->avail +
1222 num * sizeof(*vq->avail->ring) + s,
1223 VHOST_ADDR_AVAIL) &&
1224 iotlb_access_ok(vq, VHOST_ACCESS_WO, (u64)(uintptr_t)vq->used,
1225 sizeof *vq->used +
1226 num * sizeof(*vq->used->ring) + s,
1227 VHOST_ADDR_USED);
1228 }
1229 EXPORT_SYMBOL_GPL(vq_iotlb_prefetch);
1230
1231 /* Can we log writes? */
1232 /* Caller should have device mutex but not vq mutex */
1233 int vhost_log_access_ok(struct vhost_dev *dev)
1234 {
1235 return memory_access_ok(dev, dev->umem, 1);
1236 }
1237 EXPORT_SYMBOL_GPL(vhost_log_access_ok);
1238
1239 /* Verify access for write logging. */
1240 /* Caller should have vq mutex and device mutex */
1241 static int vq_log_access_ok(struct vhost_virtqueue *vq,
1242 void __user *log_base)
1243 {
1244 size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
1245
1246 return vq_memory_access_ok(log_base, vq->umem,
1247 vhost_has_feature(vq, VHOST_F_LOG_ALL)) &&
1248 (!vq->log_used || log_access_ok(log_base, vq->log_addr,
1249 sizeof *vq->used +
1250 vq->num * sizeof *vq->used->ring + s));
1251 }
1252
1253 /* Can we start vq? */
1254 /* Caller should have vq mutex and device mutex */
1255 int vhost_vq_access_ok(struct vhost_virtqueue *vq)
1256 {
1257 if (vq->iotlb) {
1258 /* When device IOTLB was used, the access validation
1259 * will be validated during prefetching.
1260 */
1261 return 1;
1262 }
1263 return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used) &&
1264 vq_log_access_ok(vq, vq->log_base);
1265 }
1266 EXPORT_SYMBOL_GPL(vhost_vq_access_ok);
1267
1268 static struct vhost_umem *vhost_umem_alloc(void)
1269 {
1270 struct vhost_umem *umem = kvzalloc(sizeof(*umem), GFP_KERNEL);
1271
1272 if (!umem)
1273 return NULL;
1274
1275 umem->umem_tree = RB_ROOT;
1276 umem->numem = 0;
1277 INIT_LIST_HEAD(&umem->umem_list);
1278
1279 return umem;
1280 }
1281
1282 static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
1283 {
1284 struct vhost_memory mem, *newmem;
1285 struct vhost_memory_region *region;
1286 struct vhost_umem *newumem, *oldumem;
1287 unsigned long size = offsetof(struct vhost_memory, regions);
1288 int i;
1289
1290 if (copy_from_user(&mem, m, size))
1291 return -EFAULT;
1292 if (mem.padding)
1293 return -EOPNOTSUPP;
1294 if (mem.nregions > max_mem_regions)
1295 return -E2BIG;
1296 newmem = kvzalloc(size + mem.nregions * sizeof(*m->regions), GFP_KERNEL);
1297 if (!newmem)
1298 return -ENOMEM;
1299
1300 memcpy(newmem, &mem, size);
1301 if (copy_from_user(newmem->regions, m->regions,
1302 mem.nregions * sizeof *m->regions)) {
1303 kvfree(newmem);
1304 return -EFAULT;
1305 }
1306
1307 newumem = vhost_umem_alloc();
1308 if (!newumem) {
1309 kvfree(newmem);
1310 return -ENOMEM;
1311 }
1312
1313 for (region = newmem->regions;
1314 region < newmem->regions + mem.nregions;
1315 region++) {
1316 if (vhost_new_umem_range(newumem,
1317 region->guest_phys_addr,
1318 region->memory_size,
1319 region->guest_phys_addr +
1320 region->memory_size - 1,
1321 region->userspace_addr,
1322 VHOST_ACCESS_RW))
1323 goto err;
1324 }
1325
1326 if (!memory_access_ok(d, newumem, 0))
1327 goto err;
1328
1329 oldumem = d->umem;
1330 d->umem = newumem;
1331
1332 /* All memory accesses are done under some VQ mutex. */
1333 for (i = 0; i < d->nvqs; ++i) {
1334 mutex_lock(&d->vqs[i]->mutex);
1335 d->vqs[i]->umem = newumem;
1336 mutex_unlock(&d->vqs[i]->mutex);
1337 }
1338
1339 kvfree(newmem);
1340 vhost_umem_clean(oldumem);
1341 return 0;
1342
1343 err:
1344 vhost_umem_clean(newumem);
1345 kvfree(newmem);
1346 return -EFAULT;
1347 }
1348
1349 long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp)
1350 {
1351 struct file *eventfp, *filep = NULL;
1352 bool pollstart = false, pollstop = false;
1353 struct eventfd_ctx *ctx = NULL;
1354 u32 __user *idxp = argp;
1355 struct vhost_virtqueue *vq;
1356 struct vhost_vring_state s;
1357 struct vhost_vring_file f;
1358 struct vhost_vring_addr a;
1359 u32 idx;
1360 long r;
1361
1362 r = get_user(idx, idxp);
1363 if (r < 0)
1364 return r;
1365 if (idx >= d->nvqs)
1366 return -ENOBUFS;
1367
1368 vq = d->vqs[idx];
1369
1370 mutex_lock(&vq->mutex);
1371
1372 switch (ioctl) {
1373 case VHOST_SET_VRING_NUM:
1374 /* Resizing ring with an active backend?
1375 * You don't want to do that. */
1376 if (vq->private_data) {
1377 r = -EBUSY;
1378 break;
1379 }
1380 if (copy_from_user(&s, argp, sizeof s)) {
1381 r = -EFAULT;
1382 break;
1383 }
1384 if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) {
1385 r = -EINVAL;
1386 break;
1387 }
1388 vq->num = s.num;
1389 break;
1390 case VHOST_SET_VRING_BASE:
1391 /* Moving base with an active backend?
1392 * You don't want to do that. */
1393 if (vq->private_data) {
1394 r = -EBUSY;
1395 break;
1396 }
1397 if (copy_from_user(&s, argp, sizeof s)) {
1398 r = -EFAULT;
1399 break;
1400 }
1401 if (s.num > 0xffff) {
1402 r = -EINVAL;
1403 break;
1404 }
1405 vq->last_avail_idx = vq->last_used_event = s.num;
1406 /* Forget the cached index value. */
1407 vq->avail_idx = vq->last_avail_idx;
1408 break;
1409 case VHOST_GET_VRING_BASE:
1410 s.index = idx;
1411 s.num = vq->last_avail_idx;
1412 if (copy_to_user(argp, &s, sizeof s))
1413 r = -EFAULT;
1414 break;
1415 case VHOST_SET_VRING_ADDR:
1416 if (copy_from_user(&a, argp, sizeof a)) {
1417 r = -EFAULT;
1418 break;
1419 }
1420 if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) {
1421 r = -EOPNOTSUPP;
1422 break;
1423 }
1424 /* For 32bit, verify that the top 32bits of the user
1425 data are set to zero. */
1426 if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr ||
1427 (u64)(unsigned long)a.used_user_addr != a.used_user_addr ||
1428 (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) {
1429 r = -EFAULT;
1430 break;
1431 }
1432
1433 /* Make sure it's safe to cast pointers to vring types. */
1434 BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE);
1435 BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE);
1436 if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) ||
1437 (a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) ||
1438 (a.log_guest_addr & (VRING_USED_ALIGN_SIZE - 1))) {
1439 r = -EINVAL;
1440 break;
1441 }
1442
1443 /* We only verify access here if backend is configured.
1444 * If it is not, we don't as size might not have been setup.
1445 * We will verify when backend is configured. */
1446 if (vq->private_data) {
1447 if (!vq_access_ok(vq, vq->num,
1448 (void __user *)(unsigned long)a.desc_user_addr,
1449 (void __user *)(unsigned long)a.avail_user_addr,
1450 (void __user *)(unsigned long)a.used_user_addr)) {
1451 r = -EINVAL;
1452 break;
1453 }
1454
1455 /* Also validate log access for used ring if enabled. */
1456 if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) &&
1457 !log_access_ok(vq->log_base, a.log_guest_addr,
1458 sizeof *vq->used +
1459 vq->num * sizeof *vq->used->ring)) {
1460 r = -EINVAL;
1461 break;
1462 }
1463 }
1464
1465 vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG));
1466 vq->desc = (void __user *)(unsigned long)a.desc_user_addr;
1467 vq->avail = (void __user *)(unsigned long)a.avail_user_addr;
1468 vq->log_addr = a.log_guest_addr;
1469 vq->used = (void __user *)(unsigned long)a.used_user_addr;
1470 break;
1471 case VHOST_SET_VRING_KICK:
1472 if (copy_from_user(&f, argp, sizeof f)) {
1473 r = -EFAULT;
1474 break;
1475 }
1476 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
1477 if (IS_ERR(eventfp)) {
1478 r = PTR_ERR(eventfp);
1479 break;
1480 }
1481 if (eventfp != vq->kick) {
1482 pollstop = (filep = vq->kick) != NULL;
1483 pollstart = (vq->kick = eventfp) != NULL;
1484 } else
1485 filep = eventfp;
1486 break;
1487 case VHOST_SET_VRING_CALL:
1488 if (copy_from_user(&f, argp, sizeof f)) {
1489 r = -EFAULT;
1490 break;
1491 }
1492 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
1493 if (IS_ERR(eventfp)) {
1494 r = PTR_ERR(eventfp);
1495 break;
1496 }
1497 if (eventfp != vq->call) {
1498 filep = vq->call;
1499 ctx = vq->call_ctx;
1500 vq->call = eventfp;
1501 vq->call_ctx = eventfp ?
1502 eventfd_ctx_fileget(eventfp) : NULL;
1503 } else
1504 filep = eventfp;
1505 break;
1506 case VHOST_SET_VRING_ERR:
1507 if (copy_from_user(&f, argp, sizeof f)) {
1508 r = -EFAULT;
1509 break;
1510 }
1511 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
1512 if (IS_ERR(eventfp)) {
1513 r = PTR_ERR(eventfp);
1514 break;
1515 }
1516 if (eventfp != vq->error) {
1517 filep = vq->error;
1518 vq->error = eventfp;
1519 ctx = vq->error_ctx;
1520 vq->error_ctx = eventfp ?
1521 eventfd_ctx_fileget(eventfp) : NULL;
1522 } else
1523 filep = eventfp;
1524 break;
1525 case VHOST_SET_VRING_ENDIAN:
1526 r = vhost_set_vring_endian(vq, argp);
1527 break;
1528 case VHOST_GET_VRING_ENDIAN:
1529 r = vhost_get_vring_endian(vq, idx, argp);
1530 break;
1531 case VHOST_SET_VRING_BUSYLOOP_TIMEOUT:
1532 if (copy_from_user(&s, argp, sizeof(s))) {
1533 r = -EFAULT;
1534 break;
1535 }
1536 vq->busyloop_timeout = s.num;
1537 break;
1538 case VHOST_GET_VRING_BUSYLOOP_TIMEOUT:
1539 s.index = idx;
1540 s.num = vq->busyloop_timeout;
1541 if (copy_to_user(argp, &s, sizeof(s)))
1542 r = -EFAULT;
1543 break;
1544 default:
1545 r = -ENOIOCTLCMD;
1546 }
1547
1548 if (pollstop && vq->handle_kick)
1549 vhost_poll_stop(&vq->poll);
1550
1551 if (ctx)
1552 eventfd_ctx_put(ctx);
1553 if (filep)
1554 fput(filep);
1555
1556 if (pollstart && vq->handle_kick)
1557 r = vhost_poll_start(&vq->poll, vq->kick);
1558
1559 mutex_unlock(&vq->mutex);
1560
1561 if (pollstop && vq->handle_kick)
1562 vhost_poll_flush(&vq->poll);
1563 return r;
1564 }
1565 EXPORT_SYMBOL_GPL(vhost_vring_ioctl);
1566
1567 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled)
1568 {
1569 struct vhost_umem *niotlb, *oiotlb;
1570 int i;
1571
1572 niotlb = vhost_umem_alloc();
1573 if (!niotlb)
1574 return -ENOMEM;
1575
1576 oiotlb = d->iotlb;
1577 d->iotlb = niotlb;
1578
1579 for (i = 0; i < d->nvqs; ++i) {
1580 mutex_lock(&d->vqs[i]->mutex);
1581 d->vqs[i]->iotlb = niotlb;
1582 mutex_unlock(&d->vqs[i]->mutex);
1583 }
1584
1585 vhost_umem_clean(oiotlb);
1586
1587 return 0;
1588 }
1589 EXPORT_SYMBOL_GPL(vhost_init_device_iotlb);
1590
1591 /* Caller must have device mutex */
1592 long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
1593 {
1594 struct file *eventfp, *filep = NULL;
1595 struct eventfd_ctx *ctx = NULL;
1596 u64 p;
1597 long r;
1598 int i, fd;
1599
1600 /* If you are not the owner, you can become one */
1601 if (ioctl == VHOST_SET_OWNER) {
1602 r = vhost_dev_set_owner(d);
1603 goto done;
1604 }
1605
1606 /* You must be the owner to do anything else */
1607 r = vhost_dev_check_owner(d);
1608 if (r)
1609 goto done;
1610
1611 switch (ioctl) {
1612 case VHOST_SET_MEM_TABLE:
1613 r = vhost_set_memory(d, argp);
1614 break;
1615 case VHOST_SET_LOG_BASE:
1616 if (copy_from_user(&p, argp, sizeof p)) {
1617 r = -EFAULT;
1618 break;
1619 }
1620 if ((u64)(unsigned long)p != p) {
1621 r = -EFAULT;
1622 break;
1623 }
1624 for (i = 0; i < d->nvqs; ++i) {
1625 struct vhost_virtqueue *vq;
1626 void __user *base = (void __user *)(unsigned long)p;
1627 vq = d->vqs[i];
1628 mutex_lock(&vq->mutex);
1629 /* If ring is inactive, will check when it's enabled. */
1630 if (vq->private_data && !vq_log_access_ok(vq, base))
1631 r = -EFAULT;
1632 else
1633 vq->log_base = base;
1634 mutex_unlock(&vq->mutex);
1635 }
1636 break;
1637 case VHOST_SET_LOG_FD:
1638 r = get_user(fd, (int __user *)argp);
1639 if (r < 0)
1640 break;
1641 eventfp = fd == -1 ? NULL : eventfd_fget(fd);
1642 if (IS_ERR(eventfp)) {
1643 r = PTR_ERR(eventfp);
1644 break;
1645 }
1646 if (eventfp != d->log_file) {
1647 filep = d->log_file;
1648 d->log_file = eventfp;
1649 ctx = d->log_ctx;
1650 d->log_ctx = eventfp ?
1651 eventfd_ctx_fileget(eventfp) : NULL;
1652 } else
1653 filep = eventfp;
1654 for (i = 0; i < d->nvqs; ++i) {
1655 mutex_lock(&d->vqs[i]->mutex);
1656 d->vqs[i]->log_ctx = d->log_ctx;
1657 mutex_unlock(&d->vqs[i]->mutex);
1658 }
1659 if (ctx)
1660 eventfd_ctx_put(ctx);
1661 if (filep)
1662 fput(filep);
1663 break;
1664 default:
1665 r = -ENOIOCTLCMD;
1666 break;
1667 }
1668 done:
1669 return r;
1670 }
1671 EXPORT_SYMBOL_GPL(vhost_dev_ioctl);
1672
1673 /* TODO: This is really inefficient. We need something like get_user()
1674 * (instruction directly accesses the data, with an exception table entry
1675 * returning -EFAULT). See Documentation/x86/exception-tables.txt.
1676 */
1677 static int set_bit_to_user(int nr, void __user *addr)
1678 {
1679 unsigned long log = (unsigned long)addr;
1680 struct page *page;
1681 void *base;
1682 int bit = nr + (log % PAGE_SIZE) * 8;
1683 int r;
1684
1685 r = get_user_pages_fast(log, 1, 1, &page);
1686 if (r < 0)
1687 return r;
1688 BUG_ON(r != 1);
1689 base = kmap_atomic(page);
1690 set_bit(bit, base);
1691 kunmap_atomic(base);
1692 set_page_dirty_lock(page);
1693 put_page(page);
1694 return 0;
1695 }
1696
1697 static int log_write(void __user *log_base,
1698 u64 write_address, u64 write_length)
1699 {
1700 u64 write_page = write_address / VHOST_PAGE_SIZE;
1701 int r;
1702
1703 if (!write_length)
1704 return 0;
1705 write_length += write_address % VHOST_PAGE_SIZE;
1706 for (;;) {
1707 u64 base = (u64)(unsigned long)log_base;
1708 u64 log = base + write_page / 8;
1709 int bit = write_page % 8;
1710 if ((u64)(unsigned long)log != log)
1711 return -EFAULT;
1712 r = set_bit_to_user(bit, (void __user *)(unsigned long)log);
1713 if (r < 0)
1714 return r;
1715 if (write_length <= VHOST_PAGE_SIZE)
1716 break;
1717 write_length -= VHOST_PAGE_SIZE;
1718 write_page += 1;
1719 }
1720 return r;
1721 }
1722
1723 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
1724 unsigned int log_num, u64 len)
1725 {
1726 int i, r;
1727
1728 /* Make sure data written is seen before log. */
1729 smp_wmb();
1730 for (i = 0; i < log_num; ++i) {
1731 u64 l = min(log[i].len, len);
1732 r = log_write(vq->log_base, log[i].addr, l);
1733 if (r < 0)
1734 return r;
1735 len -= l;
1736 if (!len) {
1737 if (vq->log_ctx)
1738 eventfd_signal(vq->log_ctx, 1);
1739 return 0;
1740 }
1741 }
1742 /* Length written exceeds what we have stored. This is a bug. */
1743 BUG();
1744 return 0;
1745 }
1746 EXPORT_SYMBOL_GPL(vhost_log_write);
1747
1748 static int vhost_update_used_flags(struct vhost_virtqueue *vq)
1749 {
1750 void __user *used;
1751 if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags),
1752 &vq->used->flags) < 0)
1753 return -EFAULT;
1754 if (unlikely(vq->log_used)) {
1755 /* Make sure the flag is seen before log. */
1756 smp_wmb();
1757 /* Log used flag write. */
1758 used = &vq->used->flags;
1759 log_write(vq->log_base, vq->log_addr +
1760 (used - (void __user *)vq->used),
1761 sizeof vq->used->flags);
1762 if (vq->log_ctx)
1763 eventfd_signal(vq->log_ctx, 1);
1764 }
1765 return 0;
1766 }
1767
1768 static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
1769 {
1770 if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx),
1771 vhost_avail_event(vq)))
1772 return -EFAULT;
1773 if (unlikely(vq->log_used)) {
1774 void __user *used;
1775 /* Make sure the event is seen before log. */
1776 smp_wmb();
1777 /* Log avail event write */
1778 used = vhost_avail_event(vq);
1779 log_write(vq->log_base, vq->log_addr +
1780 (used - (void __user *)vq->used),
1781 sizeof *vhost_avail_event(vq));
1782 if (vq->log_ctx)
1783 eventfd_signal(vq->log_ctx, 1);
1784 }
1785 return 0;
1786 }
1787
1788 int vhost_vq_init_access(struct vhost_virtqueue *vq)
1789 {
1790 __virtio16 last_used_idx;
1791 int r;
1792 bool is_le = vq->is_le;
1793
1794 if (!vq->private_data)
1795 return 0;
1796
1797 vhost_init_is_le(vq);
1798
1799 r = vhost_update_used_flags(vq);
1800 if (r)
1801 goto err;
1802 vq->signalled_used_valid = false;
1803 if (!vq->iotlb &&
1804 !access_ok(VERIFY_READ, &vq->used->idx, sizeof vq->used->idx)) {
1805 r = -EFAULT;
1806 goto err;
1807 }
1808 r = vhost_get_used(vq, last_used_idx, &vq->used->idx);
1809 if (r) {
1810 vq_err(vq, "Can't access used idx at %p\n",
1811 &vq->used->idx);
1812 goto err;
1813 }
1814 vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx);
1815 return 0;
1816
1817 err:
1818 vq->is_le = is_le;
1819 return r;
1820 }
1821 EXPORT_SYMBOL_GPL(vhost_vq_init_access);
1822
1823 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
1824 struct iovec iov[], int iov_size, int access)
1825 {
1826 const struct vhost_umem_node *node;
1827 struct vhost_dev *dev = vq->dev;
1828 struct vhost_umem *umem = dev->iotlb ? dev->iotlb : dev->umem;
1829 struct iovec *_iov;
1830 u64 s = 0;
1831 int ret = 0;
1832
1833 while ((u64)len > s) {
1834 u64 size;
1835 if (unlikely(ret >= iov_size)) {
1836 ret = -ENOBUFS;
1837 break;
1838 }
1839
1840 node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
1841 addr, addr + len - 1);
1842 if (node == NULL || node->start > addr) {
1843 if (umem != dev->iotlb) {
1844 ret = -EFAULT;
1845 break;
1846 }
1847 ret = -EAGAIN;
1848 break;
1849 } else if (!(node->perm & access)) {
1850 ret = -EPERM;
1851 break;
1852 }
1853
1854 _iov = iov + ret;
1855 size = node->size - addr + node->start;
1856 _iov->iov_len = min((u64)len - s, size);
1857 _iov->iov_base = (void __user *)(unsigned long)
1858 (node->userspace_addr + addr - node->start);
1859 s += size;
1860 addr += size;
1861 ++ret;
1862 }
1863
1864 if (ret == -EAGAIN)
1865 vhost_iotlb_miss(vq, addr, access);
1866 return ret;
1867 }
1868
1869 /* Each buffer in the virtqueues is actually a chain of descriptors. This
1870 * function returns the next descriptor in the chain,
1871 * or -1U if we're at the end. */
1872 static unsigned next_desc(struct vhost_virtqueue *vq, struct vring_desc *desc)
1873 {
1874 unsigned int next;
1875
1876 /* If this descriptor says it doesn't chain, we're done. */
1877 if (!(desc->flags & cpu_to_vhost16(vq, VRING_DESC_F_NEXT)))
1878 return -1U;
1879
1880 /* Check they're not leading us off end of descriptors. */
1881 next = vhost16_to_cpu(vq, desc->next);
1882 /* Make sure compiler knows to grab that: we don't want it changing! */
1883 /* We will use the result as an index in an array, so most
1884 * architectures only need a compiler barrier here. */
1885 read_barrier_depends();
1886
1887 return next;
1888 }
1889
1890 static int get_indirect(struct vhost_virtqueue *vq,
1891 struct iovec iov[], unsigned int iov_size,
1892 unsigned int *out_num, unsigned int *in_num,
1893 struct vhost_log *log, unsigned int *log_num,
1894 struct vring_desc *indirect)
1895 {
1896 struct vring_desc desc;
1897 unsigned int i = 0, count, found = 0;
1898 u32 len = vhost32_to_cpu(vq, indirect->len);
1899 struct iov_iter from;
1900 int ret, access;
1901
1902 /* Sanity check */
1903 if (unlikely(len % sizeof desc)) {
1904 vq_err(vq, "Invalid length in indirect descriptor: "
1905 "len 0x%llx not multiple of 0x%zx\n",
1906 (unsigned long long)len,
1907 sizeof desc);
1908 return -EINVAL;
1909 }
1910
1911 ret = translate_desc(vq, vhost64_to_cpu(vq, indirect->addr), len, vq->indirect,
1912 UIO_MAXIOV, VHOST_ACCESS_RO);
1913 if (unlikely(ret < 0)) {
1914 if (ret != -EAGAIN)
1915 vq_err(vq, "Translation failure %d in indirect.\n", ret);
1916 return ret;
1917 }
1918 iov_iter_init(&from, READ, vq->indirect, ret, len);
1919
1920 /* We will use the result as an address to read from, so most
1921 * architectures only need a compiler barrier here. */
1922 read_barrier_depends();
1923
1924 count = len / sizeof desc;
1925 /* Buffers are chained via a 16 bit next field, so
1926 * we can have at most 2^16 of these. */
1927 if (unlikely(count > USHRT_MAX + 1)) {
1928 vq_err(vq, "Indirect buffer length too big: %d\n",
1929 indirect->len);
1930 return -E2BIG;
1931 }
1932
1933 do {
1934 unsigned iov_count = *in_num + *out_num;
1935 if (unlikely(++found > count)) {
1936 vq_err(vq, "Loop detected: last one at %u "
1937 "indirect size %u\n",
1938 i, count);
1939 return -EINVAL;
1940 }
1941 if (unlikely(!copy_from_iter_full(&desc, sizeof(desc), &from))) {
1942 vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
1943 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
1944 return -EINVAL;
1945 }
1946 if (unlikely(desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT))) {
1947 vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n",
1948 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
1949 return -EINVAL;
1950 }
1951
1952 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
1953 access = VHOST_ACCESS_WO;
1954 else
1955 access = VHOST_ACCESS_RO;
1956
1957 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
1958 vhost32_to_cpu(vq, desc.len), iov + iov_count,
1959 iov_size - iov_count, access);
1960 if (unlikely(ret < 0)) {
1961 if (ret != -EAGAIN)
1962 vq_err(vq, "Translation failure %d indirect idx %d\n",
1963 ret, i);
1964 return ret;
1965 }
1966 /* If this is an input descriptor, increment that count. */
1967 if (access == VHOST_ACCESS_WO) {
1968 *in_num += ret;
1969 if (unlikely(log)) {
1970 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
1971 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
1972 ++*log_num;
1973 }
1974 } else {
1975 /* If it's an output descriptor, they're all supposed
1976 * to come before any input descriptors. */
1977 if (unlikely(*in_num)) {
1978 vq_err(vq, "Indirect descriptor "
1979 "has out after in: idx %d\n", i);
1980 return -EINVAL;
1981 }
1982 *out_num += ret;
1983 }
1984 } while ((i = next_desc(vq, &desc)) != -1);
1985 return 0;
1986 }
1987
1988 /* This looks in the virtqueue and for the first available buffer, and converts
1989 * it to an iovec for convenient access. Since descriptors consist of some
1990 * number of output then some number of input descriptors, it's actually two
1991 * iovecs, but we pack them into one and note how many of each there were.
1992 *
1993 * This function returns the descriptor number found, or vq->num (which is
1994 * never a valid descriptor number) if none was found. A negative code is
1995 * returned on error. */
1996 int vhost_get_vq_desc(struct vhost_virtqueue *vq,
1997 struct iovec iov[], unsigned int iov_size,
1998 unsigned int *out_num, unsigned int *in_num,
1999 struct vhost_log *log, unsigned int *log_num)
2000 {
2001 struct vring_desc desc;
2002 unsigned int i, head, found = 0;
2003 u16 last_avail_idx;
2004 __virtio16 avail_idx;
2005 __virtio16 ring_head;
2006 int ret, access;
2007
2008 /* Check it isn't doing very strange things with descriptor numbers. */
2009 last_avail_idx = vq->last_avail_idx;
2010
2011 if (vq->avail_idx == vq->last_avail_idx) {
2012 if (unlikely(vhost_get_avail(vq, avail_idx, &vq->avail->idx))) {
2013 vq_err(vq, "Failed to access avail idx at %p\n",
2014 &vq->avail->idx);
2015 return -EFAULT;
2016 }
2017 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2018
2019 if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) {
2020 vq_err(vq, "Guest moved used index from %u to %u",
2021 last_avail_idx, vq->avail_idx);
2022 return -EFAULT;
2023 }
2024
2025 /* If there's nothing new since last we looked, return
2026 * invalid.
2027 */
2028 if (vq->avail_idx == last_avail_idx)
2029 return vq->num;
2030
2031 /* Only get avail ring entries after they have been
2032 * exposed by guest.
2033 */
2034 smp_rmb();
2035 }
2036
2037 /* Grab the next descriptor number they're advertising, and increment
2038 * the index we've seen. */
2039 if (unlikely(vhost_get_avail(vq, ring_head,
2040 &vq->avail->ring[last_avail_idx & (vq->num - 1)]))) {
2041 vq_err(vq, "Failed to read head: idx %d address %p\n",
2042 last_avail_idx,
2043 &vq->avail->ring[last_avail_idx % vq->num]);
2044 return -EFAULT;
2045 }
2046
2047 head = vhost16_to_cpu(vq, ring_head);
2048
2049 /* If their number is silly, that's an error. */
2050 if (unlikely(head >= vq->num)) {
2051 vq_err(vq, "Guest says index %u > %u is available",
2052 head, vq->num);
2053 return -EINVAL;
2054 }
2055
2056 /* When we start there are none of either input nor output. */
2057 *out_num = *in_num = 0;
2058 if (unlikely(log))
2059 *log_num = 0;
2060
2061 i = head;
2062 do {
2063 unsigned iov_count = *in_num + *out_num;
2064 if (unlikely(i >= vq->num)) {
2065 vq_err(vq, "Desc index is %u > %u, head = %u",
2066 i, vq->num, head);
2067 return -EINVAL;
2068 }
2069 if (unlikely(++found > vq->num)) {
2070 vq_err(vq, "Loop detected: last one at %u "
2071 "vq size %u head %u\n",
2072 i, vq->num, head);
2073 return -EINVAL;
2074 }
2075 ret = vhost_copy_from_user(vq, &desc, vq->desc + i,
2076 sizeof desc);
2077 if (unlikely(ret)) {
2078 vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
2079 i, vq->desc + i);
2080 return -EFAULT;
2081 }
2082 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT)) {
2083 ret = get_indirect(vq, iov, iov_size,
2084 out_num, in_num,
2085 log, log_num, &desc);
2086 if (unlikely(ret < 0)) {
2087 if (ret != -EAGAIN)
2088 vq_err(vq, "Failure detected "
2089 "in indirect descriptor at idx %d\n", i);
2090 return ret;
2091 }
2092 continue;
2093 }
2094
2095 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
2096 access = VHOST_ACCESS_WO;
2097 else
2098 access = VHOST_ACCESS_RO;
2099 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
2100 vhost32_to_cpu(vq, desc.len), iov + iov_count,
2101 iov_size - iov_count, access);
2102 if (unlikely(ret < 0)) {
2103 if (ret != -EAGAIN)
2104 vq_err(vq, "Translation failure %d descriptor idx %d\n",
2105 ret, i);
2106 return ret;
2107 }
2108 if (access == VHOST_ACCESS_WO) {
2109 /* If this is an input descriptor,
2110 * increment that count. */
2111 *in_num += ret;
2112 if (unlikely(log)) {
2113 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
2114 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
2115 ++*log_num;
2116 }
2117 } else {
2118 /* If it's an output descriptor, they're all supposed
2119 * to come before any input descriptors. */
2120 if (unlikely(*in_num)) {
2121 vq_err(vq, "Descriptor has out after in: "
2122 "idx %d\n", i);
2123 return -EINVAL;
2124 }
2125 *out_num += ret;
2126 }
2127 } while ((i = next_desc(vq, &desc)) != -1);
2128
2129 /* On success, increment avail index. */
2130 vq->last_avail_idx++;
2131
2132 /* Assume notifications from guest are disabled at this point,
2133 * if they aren't we would need to update avail_event index. */
2134 BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY));
2135 return head;
2136 }
2137 EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
2138
2139 /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
2140 void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n)
2141 {
2142 vq->last_avail_idx -= n;
2143 }
2144 EXPORT_SYMBOL_GPL(vhost_discard_vq_desc);
2145
2146 /* After we've used one of their buffers, we tell them about it. We'll then
2147 * want to notify the guest, using eventfd. */
2148 int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
2149 {
2150 struct vring_used_elem heads = {
2151 cpu_to_vhost32(vq, head),
2152 cpu_to_vhost32(vq, len)
2153 };
2154
2155 return vhost_add_used_n(vq, &heads, 1);
2156 }
2157 EXPORT_SYMBOL_GPL(vhost_add_used);
2158
2159 static int __vhost_add_used_n(struct vhost_virtqueue *vq,
2160 struct vring_used_elem *heads,
2161 unsigned count)
2162 {
2163 struct vring_used_elem __user *used;
2164 u16 old, new;
2165 int start;
2166
2167 start = vq->last_used_idx & (vq->num - 1);
2168 used = vq->used->ring + start;
2169 if (count == 1) {
2170 if (vhost_put_user(vq, heads[0].id, &used->id)) {
2171 vq_err(vq, "Failed to write used id");
2172 return -EFAULT;
2173 }
2174 if (vhost_put_user(vq, heads[0].len, &used->len)) {
2175 vq_err(vq, "Failed to write used len");
2176 return -EFAULT;
2177 }
2178 } else if (vhost_copy_to_user(vq, used, heads, count * sizeof *used)) {
2179 vq_err(vq, "Failed to write used");
2180 return -EFAULT;
2181 }
2182 if (unlikely(vq->log_used)) {
2183 /* Make sure data is seen before log. */
2184 smp_wmb();
2185 /* Log used ring entry write. */
2186 log_write(vq->log_base,
2187 vq->log_addr +
2188 ((void __user *)used - (void __user *)vq->used),
2189 count * sizeof *used);
2190 }
2191 old = vq->last_used_idx;
2192 new = (vq->last_used_idx += count);
2193 /* If the driver never bothers to signal in a very long while,
2194 * used index might wrap around. If that happens, invalidate
2195 * signalled_used index we stored. TODO: make sure driver
2196 * signals at least once in 2^16 and remove this. */
2197 if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old)))
2198 vq->signalled_used_valid = false;
2199 return 0;
2200 }
2201
2202 /* After we've used one of their buffers, we tell them about it. We'll then
2203 * want to notify the guest, using eventfd. */
2204 int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
2205 unsigned count)
2206 {
2207 int start, n, r;
2208
2209 start = vq->last_used_idx & (vq->num - 1);
2210 n = vq->num - start;
2211 if (n < count) {
2212 r = __vhost_add_used_n(vq, heads, n);
2213 if (r < 0)
2214 return r;
2215 heads += n;
2216 count -= n;
2217 }
2218 r = __vhost_add_used_n(vq, heads, count);
2219
2220 /* Make sure buffer is written before we update index. */
2221 smp_wmb();
2222 if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx),
2223 &vq->used->idx)) {
2224 vq_err(vq, "Failed to increment used idx");
2225 return -EFAULT;
2226 }
2227 if (unlikely(vq->log_used)) {
2228 /* Log used index update. */
2229 log_write(vq->log_base,
2230 vq->log_addr + offsetof(struct vring_used, idx),
2231 sizeof vq->used->idx);
2232 if (vq->log_ctx)
2233 eventfd_signal(vq->log_ctx, 1);
2234 }
2235 return r;
2236 }
2237 EXPORT_SYMBOL_GPL(vhost_add_used_n);
2238
2239 static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2240 {
2241 __u16 old, new;
2242 __virtio16 event;
2243 bool v;
2244
2245 if (vhost_has_feature(vq, VIRTIO_F_NOTIFY_ON_EMPTY) &&
2246 unlikely(vq->avail_idx == vq->last_avail_idx))
2247 return true;
2248
2249 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2250 __virtio16 flags;
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 if (vhost_get_avail(vq, flags, &vq->avail->flags)) {
2256 vq_err(vq, "Failed to get flags");
2257 return true;
2258 }
2259 return !(flags & cpu_to_vhost16(vq, VRING_AVAIL_F_NO_INTERRUPT));
2260 }
2261 old = vq->signalled_used;
2262 v = vq->signalled_used_valid;
2263 new = vq->signalled_used = vq->last_used_idx;
2264 vq->signalled_used_valid = true;
2265
2266 if (unlikely(!v))
2267 return true;
2268
2269 /* We're sure if the following conditions are met, there's no
2270 * need to notify guest:
2271 * 1) cached used event is ahead of new
2272 * 2) old to new updating does not cross cached used event. */
2273 if (vring_need_event(vq->last_used_event, new + vq->num, new) &&
2274 !vring_need_event(vq->last_used_event, new, old))
2275 return false;
2276
2277 /* Flush out used index updates. This is paired
2278 * with the barrier that the Guest executes when enabling
2279 * interrupts. */
2280 smp_mb();
2281
2282 if (vhost_get_avail(vq, event, vhost_used_event(vq))) {
2283 vq_err(vq, "Failed to get used event idx");
2284 return true;
2285 }
2286 vq->last_used_event = vhost16_to_cpu(vq, event);
2287
2288 return vring_need_event(vq->last_used_event, new, old);
2289 }
2290
2291 /* This actually signals the guest, using eventfd. */
2292 void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2293 {
2294 /* Signal the Guest tell them we used something up. */
2295 if (vq->call_ctx && vhost_notify(dev, vq))
2296 eventfd_signal(vq->call_ctx, 1);
2297 }
2298 EXPORT_SYMBOL_GPL(vhost_signal);
2299
2300 /* And here's the combo meal deal. Supersize me! */
2301 void vhost_add_used_and_signal(struct vhost_dev *dev,
2302 struct vhost_virtqueue *vq,
2303 unsigned int head, int len)
2304 {
2305 vhost_add_used(vq, head, len);
2306 vhost_signal(dev, vq);
2307 }
2308 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal);
2309
2310 /* multi-buffer version of vhost_add_used_and_signal */
2311 void vhost_add_used_and_signal_n(struct vhost_dev *dev,
2312 struct vhost_virtqueue *vq,
2313 struct vring_used_elem *heads, unsigned count)
2314 {
2315 vhost_add_used_n(vq, heads, count);
2316 vhost_signal(dev, vq);
2317 }
2318 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
2319
2320 /* return true if we're sure that avaiable ring is empty */
2321 bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2322 {
2323 __virtio16 avail_idx;
2324 int r;
2325
2326 if (vq->avail_idx != vq->last_avail_idx)
2327 return false;
2328
2329 r = vhost_get_avail(vq, avail_idx, &vq->avail->idx);
2330 if (unlikely(r))
2331 return false;
2332 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2333
2334 return vq->avail_idx == vq->last_avail_idx;
2335 }
2336 EXPORT_SYMBOL_GPL(vhost_vq_avail_empty);
2337
2338 /* OK, now we need to know about added descriptors. */
2339 bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2340 {
2341 __virtio16 avail_idx;
2342 int r;
2343
2344 if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
2345 return false;
2346 vq->used_flags &= ~VRING_USED_F_NO_NOTIFY;
2347 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2348 r = vhost_update_used_flags(vq);
2349 if (r) {
2350 vq_err(vq, "Failed to enable notification at %p: %d\n",
2351 &vq->used->flags, r);
2352 return false;
2353 }
2354 } else {
2355 r = vhost_update_avail_event(vq, vq->avail_idx);
2356 if (r) {
2357 vq_err(vq, "Failed to update avail event index at %p: %d\n",
2358 vhost_avail_event(vq), r);
2359 return false;
2360 }
2361 }
2362 /* They could have slipped one in as we were doing that: make
2363 * sure it's written, then check again. */
2364 smp_mb();
2365 r = vhost_get_avail(vq, avail_idx, &vq->avail->idx);
2366 if (r) {
2367 vq_err(vq, "Failed to check avail idx at %p: %d\n",
2368 &vq->avail->idx, r);
2369 return false;
2370 }
2371
2372 return vhost16_to_cpu(vq, avail_idx) != vq->avail_idx;
2373 }
2374 EXPORT_SYMBOL_GPL(vhost_enable_notify);
2375
2376 /* We don't need to be notified again. */
2377 void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2378 {
2379 int r;
2380
2381 if (vq->used_flags & VRING_USED_F_NO_NOTIFY)
2382 return;
2383 vq->used_flags |= VRING_USED_F_NO_NOTIFY;
2384 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2385 r = vhost_update_used_flags(vq);
2386 if (r)
2387 vq_err(vq, "Failed to enable notification at %p: %d\n",
2388 &vq->used->flags, r);
2389 }
2390 }
2391 EXPORT_SYMBOL_GPL(vhost_disable_notify);
2392
2393 /* Create a new message. */
2394 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type)
2395 {
2396 struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL);
2397 if (!node)
2398 return NULL;
2399 node->vq = vq;
2400 node->msg.type = type;
2401 return node;
2402 }
2403 EXPORT_SYMBOL_GPL(vhost_new_msg);
2404
2405 void vhost_enqueue_msg(struct vhost_dev *dev, struct list_head *head,
2406 struct vhost_msg_node *node)
2407 {
2408 spin_lock(&dev->iotlb_lock);
2409 list_add_tail(&node->node, head);
2410 spin_unlock(&dev->iotlb_lock);
2411
2412 wake_up_interruptible_poll(&dev->wait, POLLIN | POLLRDNORM);
2413 }
2414 EXPORT_SYMBOL_GPL(vhost_enqueue_msg);
2415
2416 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
2417 struct list_head *head)
2418 {
2419 struct vhost_msg_node *node = NULL;
2420
2421 spin_lock(&dev->iotlb_lock);
2422 if (!list_empty(head)) {
2423 node = list_first_entry(head, struct vhost_msg_node,
2424 node);
2425 list_del(&node->node);
2426 }
2427 spin_unlock(&dev->iotlb_lock);
2428
2429 return node;
2430 }
2431 EXPORT_SYMBOL_GPL(vhost_dequeue_msg);
2432
2433
2434 static int __init vhost_init(void)
2435 {
2436 return 0;
2437 }
2438
2439 static void __exit vhost_exit(void)
2440 {
2441 }
2442
2443 module_init(vhost_init);
2444 module_exit(vhost_exit);
2445
2446 MODULE_VERSION("0.0.1");
2447 MODULE_LICENSE("GPL v2");
2448 MODULE_AUTHOR("Michael S. Tsirkin");
2449 MODULE_DESCRIPTION("Host kernel accelerator for virtio");
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