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vhost: add helper to check if a vq has been setup
[mirror_ubuntu-hirsute-kernel.git] / drivers / vhost / vhost.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (C) 2009 Red Hat, Inc.
3 * Copyright (C) 2006 Rusty Russell IBM Corporation
4 *
5 * Author: Michael S. Tsirkin <mst@redhat.com>
6 *
7 * Inspiration, some code, and most witty comments come from
8 * Documentation/virtual/lguest/lguest.c, by Rusty Russell
9 *
10 * Generic code for virtio server in host kernel.
11 */
12
13 #include <linux/eventfd.h>
14 #include <linux/vhost.h>
15 #include <linux/uio.h>
16 #include <linux/mm.h>
17 #include <linux/miscdevice.h>
18 #include <linux/mutex.h>
19 #include <linux/poll.h>
20 #include <linux/file.h>
21 #include <linux/highmem.h>
22 #include <linux/slab.h>
23 #include <linux/vmalloc.h>
24 #include <linux/kthread.h>
25 #include <linux/cgroup.h>
26 #include <linux/module.h>
27 #include <linux/sort.h>
28 #include <linux/sched/mm.h>
29 #include <linux/sched/signal.h>
30 #include <linux/interval_tree_generic.h>
31 #include <linux/nospec.h>
32 #include <linux/kcov.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 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
53 static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
54 {
55 vq->user_be = !virtio_legacy_is_little_endian();
56 }
57
58 static void vhost_enable_cross_endian_big(struct vhost_virtqueue *vq)
59 {
60 vq->user_be = true;
61 }
62
63 static void vhost_enable_cross_endian_little(struct vhost_virtqueue *vq)
64 {
65 vq->user_be = false;
66 }
67
68 static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
69 {
70 struct vhost_vring_state s;
71
72 if (vq->private_data)
73 return -EBUSY;
74
75 if (copy_from_user(&s, argp, sizeof(s)))
76 return -EFAULT;
77
78 if (s.num != VHOST_VRING_LITTLE_ENDIAN &&
79 s.num != VHOST_VRING_BIG_ENDIAN)
80 return -EINVAL;
81
82 if (s.num == VHOST_VRING_BIG_ENDIAN)
83 vhost_enable_cross_endian_big(vq);
84 else
85 vhost_enable_cross_endian_little(vq);
86
87 return 0;
88 }
89
90 static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
91 int __user *argp)
92 {
93 struct vhost_vring_state s = {
94 .index = idx,
95 .num = vq->user_be
96 };
97
98 if (copy_to_user(argp, &s, sizeof(s)))
99 return -EFAULT;
100
101 return 0;
102 }
103
104 static void vhost_init_is_le(struct vhost_virtqueue *vq)
105 {
106 /* Note for legacy virtio: user_be is initialized at reset time
107 * according to the host endianness. If userspace does not set an
108 * explicit endianness, the default behavior is native endian, as
109 * expected by legacy virtio.
110 */
111 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1) || !vq->user_be;
112 }
113 #else
114 static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
115 {
116 }
117
118 static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
119 {
120 return -ENOIOCTLCMD;
121 }
122
123 static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
124 int __user *argp)
125 {
126 return -ENOIOCTLCMD;
127 }
128
129 static void vhost_init_is_le(struct vhost_virtqueue *vq)
130 {
131 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1)
132 || virtio_legacy_is_little_endian();
133 }
134 #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
135
136 static void vhost_reset_is_le(struct vhost_virtqueue *vq)
137 {
138 vhost_init_is_le(vq);
139 }
140
141 struct vhost_flush_struct {
142 struct vhost_work work;
143 struct completion wait_event;
144 };
145
146 static void vhost_flush_work(struct vhost_work *work)
147 {
148 struct vhost_flush_struct *s;
149
150 s = container_of(work, struct vhost_flush_struct, work);
151 complete(&s->wait_event);
152 }
153
154 static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
155 poll_table *pt)
156 {
157 struct vhost_poll *poll;
158
159 poll = container_of(pt, struct vhost_poll, table);
160 poll->wqh = wqh;
161 add_wait_queue(wqh, &poll->wait);
162 }
163
164 static int vhost_poll_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync,
165 void *key)
166 {
167 struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait);
168 struct vhost_work *work = &poll->work;
169
170 if (!(key_to_poll(key) & poll->mask))
171 return 0;
172
173 if (!poll->dev->use_worker)
174 work->fn(work);
175 else
176 vhost_poll_queue(poll);
177
178 return 0;
179 }
180
181 void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn)
182 {
183 clear_bit(VHOST_WORK_QUEUED, &work->flags);
184 work->fn = fn;
185 }
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 __poll_t 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 __poll_t mask;
207
208 if (poll->wqh)
209 return 0;
210
211 mask = vfs_poll(file, &poll->table);
212 if (mask)
213 vhost_poll_wakeup(&poll->wait, 0, 0, poll_to_key(mask));
214 if (mask & EPOLLERR) {
215 vhost_poll_stop(poll);
216 return -EINVAL;
217 }
218
219 return 0;
220 }
221 EXPORT_SYMBOL_GPL(vhost_poll_start);
222
223 /* Stop polling a file. After this function returns, it becomes safe to drop the
224 * file reference. You must also flush afterwards. */
225 void vhost_poll_stop(struct vhost_poll *poll)
226 {
227 if (poll->wqh) {
228 remove_wait_queue(poll->wqh, &poll->wait);
229 poll->wqh = NULL;
230 }
231 }
232 EXPORT_SYMBOL_GPL(vhost_poll_stop);
233
234 void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work)
235 {
236 struct vhost_flush_struct flush;
237
238 if (dev->worker) {
239 init_completion(&flush.wait_event);
240 vhost_work_init(&flush.work, vhost_flush_work);
241
242 vhost_work_queue(dev, &flush.work);
243 wait_for_completion(&flush.wait_event);
244 }
245 }
246 EXPORT_SYMBOL_GPL(vhost_work_flush);
247
248 /* Flush any work that has been scheduled. When calling this, don't hold any
249 * locks that are also used by the callback. */
250 void vhost_poll_flush(struct vhost_poll *poll)
251 {
252 vhost_work_flush(poll->dev, &poll->work);
253 }
254 EXPORT_SYMBOL_GPL(vhost_poll_flush);
255
256 void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work)
257 {
258 if (!dev->worker)
259 return;
260
261 if (!test_and_set_bit(VHOST_WORK_QUEUED, &work->flags)) {
262 /* We can only add the work to the list after we're
263 * sure it was not in the list.
264 * test_and_set_bit() implies a memory barrier.
265 */
266 llist_add(&work->node, &dev->work_list);
267 wake_up_process(dev->worker);
268 }
269 }
270 EXPORT_SYMBOL_GPL(vhost_work_queue);
271
272 /* A lockless hint for busy polling code to exit the loop */
273 bool vhost_has_work(struct vhost_dev *dev)
274 {
275 return !llist_empty(&dev->work_list);
276 }
277 EXPORT_SYMBOL_GPL(vhost_has_work);
278
279 void vhost_poll_queue(struct vhost_poll *poll)
280 {
281 vhost_work_queue(poll->dev, &poll->work);
282 }
283 EXPORT_SYMBOL_GPL(vhost_poll_queue);
284
285 static void __vhost_vq_meta_reset(struct vhost_virtqueue *vq)
286 {
287 int j;
288
289 for (j = 0; j < VHOST_NUM_ADDRS; j++)
290 vq->meta_iotlb[j] = NULL;
291 }
292
293 static void vhost_vq_meta_reset(struct vhost_dev *d)
294 {
295 int i;
296
297 for (i = 0; i < d->nvqs; ++i)
298 __vhost_vq_meta_reset(d->vqs[i]);
299 }
300
301 static void vhost_vring_call_reset(struct vhost_vring_call *call_ctx)
302 {
303 call_ctx->ctx = NULL;
304 memset(&call_ctx->producer, 0x0, sizeof(struct irq_bypass_producer));
305 }
306
307 bool vhost_vq_is_setup(struct vhost_virtqueue *vq)
308 {
309 return vq->avail && vq->desc && vq->used && vhost_vq_access_ok(vq);
310 }
311 EXPORT_SYMBOL_GPL(vhost_vq_is_setup);
312
313 static void vhost_vq_reset(struct vhost_dev *dev,
314 struct vhost_virtqueue *vq)
315 {
316 vq->num = 1;
317 vq->desc = NULL;
318 vq->avail = NULL;
319 vq->used = NULL;
320 vq->last_avail_idx = 0;
321 vq->avail_idx = 0;
322 vq->last_used_idx = 0;
323 vq->signalled_used = 0;
324 vq->signalled_used_valid = false;
325 vq->used_flags = 0;
326 vq->log_used = false;
327 vq->log_addr = -1ull;
328 vq->private_data = NULL;
329 vq->acked_features = 0;
330 vq->acked_backend_features = 0;
331 vq->log_base = NULL;
332 vq->error_ctx = NULL;
333 vq->kick = NULL;
334 vq->log_ctx = NULL;
335 vhost_reset_is_le(vq);
336 vhost_disable_cross_endian(vq);
337 vq->busyloop_timeout = 0;
338 vq->umem = NULL;
339 vq->iotlb = NULL;
340 vhost_vring_call_reset(&vq->call_ctx);
341 __vhost_vq_meta_reset(vq);
342 }
343
344 static int vhost_worker(void *data)
345 {
346 struct vhost_dev *dev = data;
347 struct vhost_work *work, *work_next;
348 struct llist_node *node;
349
350 kthread_use_mm(dev->mm);
351
352 for (;;) {
353 /* mb paired w/ kthread_stop */
354 set_current_state(TASK_INTERRUPTIBLE);
355
356 if (kthread_should_stop()) {
357 __set_current_state(TASK_RUNNING);
358 break;
359 }
360
361 node = llist_del_all(&dev->work_list);
362 if (!node)
363 schedule();
364
365 node = llist_reverse_order(node);
366 /* make sure flag is seen after deletion */
367 smp_wmb();
368 llist_for_each_entry_safe(work, work_next, node, node) {
369 clear_bit(VHOST_WORK_QUEUED, &work->flags);
370 __set_current_state(TASK_RUNNING);
371 kcov_remote_start_common(dev->kcov_handle);
372 work->fn(work);
373 kcov_remote_stop();
374 if (need_resched())
375 schedule();
376 }
377 }
378 kthread_unuse_mm(dev->mm);
379 return 0;
380 }
381
382 static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq)
383 {
384 kfree(vq->indirect);
385 vq->indirect = NULL;
386 kfree(vq->log);
387 vq->log = NULL;
388 kfree(vq->heads);
389 vq->heads = NULL;
390 }
391
392 /* Helper to allocate iovec buffers for all vqs. */
393 static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
394 {
395 struct vhost_virtqueue *vq;
396 int i;
397
398 for (i = 0; i < dev->nvqs; ++i) {
399 vq = dev->vqs[i];
400 vq->indirect = kmalloc_array(UIO_MAXIOV,
401 sizeof(*vq->indirect),
402 GFP_KERNEL);
403 vq->log = kmalloc_array(dev->iov_limit, sizeof(*vq->log),
404 GFP_KERNEL);
405 vq->heads = kmalloc_array(dev->iov_limit, sizeof(*vq->heads),
406 GFP_KERNEL);
407 if (!vq->indirect || !vq->log || !vq->heads)
408 goto err_nomem;
409 }
410 return 0;
411
412 err_nomem:
413 for (; i >= 0; --i)
414 vhost_vq_free_iovecs(dev->vqs[i]);
415 return -ENOMEM;
416 }
417
418 static void vhost_dev_free_iovecs(struct vhost_dev *dev)
419 {
420 int i;
421
422 for (i = 0; i < dev->nvqs; ++i)
423 vhost_vq_free_iovecs(dev->vqs[i]);
424 }
425
426 bool vhost_exceeds_weight(struct vhost_virtqueue *vq,
427 int pkts, int total_len)
428 {
429 struct vhost_dev *dev = vq->dev;
430
431 if ((dev->byte_weight && total_len >= dev->byte_weight) ||
432 pkts >= dev->weight) {
433 vhost_poll_queue(&vq->poll);
434 return true;
435 }
436
437 return false;
438 }
439 EXPORT_SYMBOL_GPL(vhost_exceeds_weight);
440
441 static size_t vhost_get_avail_size(struct vhost_virtqueue *vq,
442 unsigned int num)
443 {
444 size_t event __maybe_unused =
445 vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
446
447 return sizeof(*vq->avail) +
448 sizeof(*vq->avail->ring) * num + event;
449 }
450
451 static size_t vhost_get_used_size(struct vhost_virtqueue *vq,
452 unsigned int num)
453 {
454 size_t event __maybe_unused =
455 vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
456
457 return sizeof(*vq->used) +
458 sizeof(*vq->used->ring) * num + event;
459 }
460
461 static size_t vhost_get_desc_size(struct vhost_virtqueue *vq,
462 unsigned int num)
463 {
464 return sizeof(*vq->desc) * num;
465 }
466
467 void vhost_dev_init(struct vhost_dev *dev,
468 struct vhost_virtqueue **vqs, int nvqs,
469 int iov_limit, int weight, int byte_weight,
470 bool use_worker,
471 int (*msg_handler)(struct vhost_dev *dev,
472 struct vhost_iotlb_msg *msg))
473 {
474 struct vhost_virtqueue *vq;
475 int i;
476
477 dev->vqs = vqs;
478 dev->nvqs = nvqs;
479 mutex_init(&dev->mutex);
480 dev->log_ctx = NULL;
481 dev->umem = NULL;
482 dev->iotlb = NULL;
483 dev->mm = NULL;
484 dev->worker = NULL;
485 dev->iov_limit = iov_limit;
486 dev->weight = weight;
487 dev->byte_weight = byte_weight;
488 dev->use_worker = use_worker;
489 dev->msg_handler = msg_handler;
490 init_llist_head(&dev->work_list);
491 init_waitqueue_head(&dev->wait);
492 INIT_LIST_HEAD(&dev->read_list);
493 INIT_LIST_HEAD(&dev->pending_list);
494 spin_lock_init(&dev->iotlb_lock);
495
496
497 for (i = 0; i < dev->nvqs; ++i) {
498 vq = dev->vqs[i];
499 vq->log = NULL;
500 vq->indirect = NULL;
501 vq->heads = NULL;
502 vq->dev = dev;
503 mutex_init(&vq->mutex);
504 vhost_vq_reset(dev, vq);
505 if (vq->handle_kick)
506 vhost_poll_init(&vq->poll, vq->handle_kick,
507 EPOLLIN, dev);
508 }
509 }
510 EXPORT_SYMBOL_GPL(vhost_dev_init);
511
512 /* Caller should have device mutex */
513 long vhost_dev_check_owner(struct vhost_dev *dev)
514 {
515 /* Are you the owner? If not, I don't think you mean to do that */
516 return dev->mm == current->mm ? 0 : -EPERM;
517 }
518 EXPORT_SYMBOL_GPL(vhost_dev_check_owner);
519
520 struct vhost_attach_cgroups_struct {
521 struct vhost_work work;
522 struct task_struct *owner;
523 int ret;
524 };
525
526 static void vhost_attach_cgroups_work(struct vhost_work *work)
527 {
528 struct vhost_attach_cgroups_struct *s;
529
530 s = container_of(work, struct vhost_attach_cgroups_struct, work);
531 s->ret = cgroup_attach_task_all(s->owner, current);
532 }
533
534 static int vhost_attach_cgroups(struct vhost_dev *dev)
535 {
536 struct vhost_attach_cgroups_struct attach;
537
538 attach.owner = current;
539 vhost_work_init(&attach.work, vhost_attach_cgroups_work);
540 vhost_work_queue(dev, &attach.work);
541 vhost_work_flush(dev, &attach.work);
542 return attach.ret;
543 }
544
545 /* Caller should have device mutex */
546 bool vhost_dev_has_owner(struct vhost_dev *dev)
547 {
548 return dev->mm;
549 }
550 EXPORT_SYMBOL_GPL(vhost_dev_has_owner);
551
552 static void vhost_attach_mm(struct vhost_dev *dev)
553 {
554 /* No owner, become one */
555 if (dev->use_worker) {
556 dev->mm = get_task_mm(current);
557 } else {
558 /* vDPA device does not use worker thead, so there's
559 * no need to hold the address space for mm. This help
560 * to avoid deadlock in the case of mmap() which may
561 * held the refcnt of the file and depends on release
562 * method to remove vma.
563 */
564 dev->mm = current->mm;
565 mmgrab(dev->mm);
566 }
567 }
568
569 static void vhost_detach_mm(struct vhost_dev *dev)
570 {
571 if (!dev->mm)
572 return;
573
574 if (dev->use_worker)
575 mmput(dev->mm);
576 else
577 mmdrop(dev->mm);
578
579 dev->mm = NULL;
580 }
581
582 /* Caller should have device mutex */
583 long vhost_dev_set_owner(struct vhost_dev *dev)
584 {
585 struct task_struct *worker;
586 int err;
587
588 /* Is there an owner already? */
589 if (vhost_dev_has_owner(dev)) {
590 err = -EBUSY;
591 goto err_mm;
592 }
593
594 vhost_attach_mm(dev);
595
596 dev->kcov_handle = kcov_common_handle();
597 if (dev->use_worker) {
598 worker = kthread_create(vhost_worker, dev,
599 "vhost-%d", current->pid);
600 if (IS_ERR(worker)) {
601 err = PTR_ERR(worker);
602 goto err_worker;
603 }
604
605 dev->worker = worker;
606 wake_up_process(worker); /* avoid contributing to loadavg */
607
608 err = vhost_attach_cgroups(dev);
609 if (err)
610 goto err_cgroup;
611 }
612
613 err = vhost_dev_alloc_iovecs(dev);
614 if (err)
615 goto err_cgroup;
616
617 return 0;
618 err_cgroup:
619 if (dev->worker) {
620 kthread_stop(dev->worker);
621 dev->worker = NULL;
622 }
623 err_worker:
624 vhost_detach_mm(dev);
625 dev->kcov_handle = 0;
626 err_mm:
627 return err;
628 }
629 EXPORT_SYMBOL_GPL(vhost_dev_set_owner);
630
631 static struct vhost_iotlb *iotlb_alloc(void)
632 {
633 return vhost_iotlb_alloc(max_iotlb_entries,
634 VHOST_IOTLB_FLAG_RETIRE);
635 }
636
637 struct vhost_iotlb *vhost_dev_reset_owner_prepare(void)
638 {
639 return iotlb_alloc();
640 }
641 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare);
642
643 /* Caller should have device mutex */
644 void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_iotlb *umem)
645 {
646 int i;
647
648 vhost_dev_cleanup(dev);
649
650 dev->umem = umem;
651 /* We don't need VQ locks below since vhost_dev_cleanup makes sure
652 * VQs aren't running.
653 */
654 for (i = 0; i < dev->nvqs; ++i)
655 dev->vqs[i]->umem = umem;
656 }
657 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner);
658
659 void vhost_dev_stop(struct vhost_dev *dev)
660 {
661 int i;
662
663 for (i = 0; i < dev->nvqs; ++i) {
664 if (dev->vqs[i]->kick && dev->vqs[i]->handle_kick) {
665 vhost_poll_stop(&dev->vqs[i]->poll);
666 vhost_poll_flush(&dev->vqs[i]->poll);
667 }
668 }
669 }
670 EXPORT_SYMBOL_GPL(vhost_dev_stop);
671
672 static void vhost_clear_msg(struct vhost_dev *dev)
673 {
674 struct vhost_msg_node *node, *n;
675
676 spin_lock(&dev->iotlb_lock);
677
678 list_for_each_entry_safe(node, n, &dev->read_list, node) {
679 list_del(&node->node);
680 kfree(node);
681 }
682
683 list_for_each_entry_safe(node, n, &dev->pending_list, node) {
684 list_del(&node->node);
685 kfree(node);
686 }
687
688 spin_unlock(&dev->iotlb_lock);
689 }
690
691 void vhost_dev_cleanup(struct vhost_dev *dev)
692 {
693 int i;
694
695 for (i = 0; i < dev->nvqs; ++i) {
696 if (dev->vqs[i]->error_ctx)
697 eventfd_ctx_put(dev->vqs[i]->error_ctx);
698 if (dev->vqs[i]->kick)
699 fput(dev->vqs[i]->kick);
700 if (dev->vqs[i]->call_ctx.ctx)
701 eventfd_ctx_put(dev->vqs[i]->call_ctx.ctx);
702 vhost_vq_reset(dev, dev->vqs[i]);
703 }
704 vhost_dev_free_iovecs(dev);
705 if (dev->log_ctx)
706 eventfd_ctx_put(dev->log_ctx);
707 dev->log_ctx = NULL;
708 /* No one will access memory at this point */
709 vhost_iotlb_free(dev->umem);
710 dev->umem = NULL;
711 vhost_iotlb_free(dev->iotlb);
712 dev->iotlb = NULL;
713 vhost_clear_msg(dev);
714 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
715 WARN_ON(!llist_empty(&dev->work_list));
716 if (dev->worker) {
717 kthread_stop(dev->worker);
718 dev->worker = NULL;
719 dev->kcov_handle = 0;
720 }
721 vhost_detach_mm(dev);
722 }
723 EXPORT_SYMBOL_GPL(vhost_dev_cleanup);
724
725 static bool log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
726 {
727 u64 a = addr / VHOST_PAGE_SIZE / 8;
728
729 /* Make sure 64 bit math will not overflow. */
730 if (a > ULONG_MAX - (unsigned long)log_base ||
731 a + (unsigned long)log_base > ULONG_MAX)
732 return false;
733
734 return access_ok(log_base + a,
735 (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8);
736 }
737
738 static bool vhost_overflow(u64 uaddr, u64 size)
739 {
740 /* Make sure 64 bit math will not overflow. */
741 return uaddr > ULONG_MAX || size > ULONG_MAX || uaddr > ULONG_MAX - size;
742 }
743
744 /* Caller should have vq mutex and device mutex. */
745 static bool vq_memory_access_ok(void __user *log_base, struct vhost_iotlb *umem,
746 int log_all)
747 {
748 struct vhost_iotlb_map *map;
749
750 if (!umem)
751 return false;
752
753 list_for_each_entry(map, &umem->list, link) {
754 unsigned long a = map->addr;
755
756 if (vhost_overflow(map->addr, map->size))
757 return false;
758
759
760 if (!access_ok((void __user *)a, map->size))
761 return false;
762 else if (log_all && !log_access_ok(log_base,
763 map->start,
764 map->size))
765 return false;
766 }
767 return true;
768 }
769
770 static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq,
771 u64 addr, unsigned int size,
772 int type)
773 {
774 const struct vhost_iotlb_map *map = vq->meta_iotlb[type];
775
776 if (!map)
777 return NULL;
778
779 return (void __user *)(uintptr_t)(map->addr + addr - map->start);
780 }
781
782 /* Can we switch to this memory table? */
783 /* Caller should have device mutex but not vq mutex */
784 static bool memory_access_ok(struct vhost_dev *d, struct vhost_iotlb *umem,
785 int log_all)
786 {
787 int i;
788
789 for (i = 0; i < d->nvqs; ++i) {
790 bool ok;
791 bool log;
792
793 mutex_lock(&d->vqs[i]->mutex);
794 log = log_all || vhost_has_feature(d->vqs[i], VHOST_F_LOG_ALL);
795 /* If ring is inactive, will check when it's enabled. */
796 if (d->vqs[i]->private_data)
797 ok = vq_memory_access_ok(d->vqs[i]->log_base,
798 umem, log);
799 else
800 ok = true;
801 mutex_unlock(&d->vqs[i]->mutex);
802 if (!ok)
803 return false;
804 }
805 return true;
806 }
807
808 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
809 struct iovec iov[], int iov_size, int access);
810
811 static int vhost_copy_to_user(struct vhost_virtqueue *vq, void __user *to,
812 const void *from, unsigned size)
813 {
814 int ret;
815
816 if (!vq->iotlb)
817 return __copy_to_user(to, from, size);
818 else {
819 /* This function should be called after iotlb
820 * prefetch, which means we're sure that all vq
821 * could be access through iotlb. So -EAGAIN should
822 * not happen in this case.
823 */
824 struct iov_iter t;
825 void __user *uaddr = vhost_vq_meta_fetch(vq,
826 (u64)(uintptr_t)to, size,
827 VHOST_ADDR_USED);
828
829 if (uaddr)
830 return __copy_to_user(uaddr, from, size);
831
832 ret = translate_desc(vq, (u64)(uintptr_t)to, size, vq->iotlb_iov,
833 ARRAY_SIZE(vq->iotlb_iov),
834 VHOST_ACCESS_WO);
835 if (ret < 0)
836 goto out;
837 iov_iter_init(&t, WRITE, vq->iotlb_iov, ret, size);
838 ret = copy_to_iter(from, size, &t);
839 if (ret == size)
840 ret = 0;
841 }
842 out:
843 return ret;
844 }
845
846 static int vhost_copy_from_user(struct vhost_virtqueue *vq, void *to,
847 void __user *from, unsigned size)
848 {
849 int ret;
850
851 if (!vq->iotlb)
852 return __copy_from_user(to, from, size);
853 else {
854 /* This function should be called after iotlb
855 * prefetch, which means we're sure that vq
856 * could be access through iotlb. So -EAGAIN should
857 * not happen in this case.
858 */
859 void __user *uaddr = vhost_vq_meta_fetch(vq,
860 (u64)(uintptr_t)from, size,
861 VHOST_ADDR_DESC);
862 struct iov_iter f;
863
864 if (uaddr)
865 return __copy_from_user(to, uaddr, size);
866
867 ret = translate_desc(vq, (u64)(uintptr_t)from, size, vq->iotlb_iov,
868 ARRAY_SIZE(vq->iotlb_iov),
869 VHOST_ACCESS_RO);
870 if (ret < 0) {
871 vq_err(vq, "IOTLB translation failure: uaddr "
872 "%p size 0x%llx\n", from,
873 (unsigned long long) size);
874 goto out;
875 }
876 iov_iter_init(&f, READ, vq->iotlb_iov, ret, size);
877 ret = copy_from_iter(to, size, &f);
878 if (ret == size)
879 ret = 0;
880 }
881
882 out:
883 return ret;
884 }
885
886 static void __user *__vhost_get_user_slow(struct vhost_virtqueue *vq,
887 void __user *addr, unsigned int size,
888 int type)
889 {
890 int ret;
891
892 ret = translate_desc(vq, (u64)(uintptr_t)addr, size, vq->iotlb_iov,
893 ARRAY_SIZE(vq->iotlb_iov),
894 VHOST_ACCESS_RO);
895 if (ret < 0) {
896 vq_err(vq, "IOTLB translation failure: uaddr "
897 "%p size 0x%llx\n", addr,
898 (unsigned long long) size);
899 return NULL;
900 }
901
902 if (ret != 1 || vq->iotlb_iov[0].iov_len != size) {
903 vq_err(vq, "Non atomic userspace memory access: uaddr "
904 "%p size 0x%llx\n", addr,
905 (unsigned long long) size);
906 return NULL;
907 }
908
909 return vq->iotlb_iov[0].iov_base;
910 }
911
912 /* This function should be called after iotlb
913 * prefetch, which means we're sure that vq
914 * could be access through iotlb. So -EAGAIN should
915 * not happen in this case.
916 */
917 static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq,
918 void __user *addr, unsigned int size,
919 int type)
920 {
921 void __user *uaddr = vhost_vq_meta_fetch(vq,
922 (u64)(uintptr_t)addr, size, type);
923 if (uaddr)
924 return uaddr;
925
926 return __vhost_get_user_slow(vq, addr, size, type);
927 }
928
929 #define vhost_put_user(vq, x, ptr) \
930 ({ \
931 int ret; \
932 if (!vq->iotlb) { \
933 ret = __put_user(x, ptr); \
934 } else { \
935 __typeof__(ptr) to = \
936 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
937 sizeof(*ptr), VHOST_ADDR_USED); \
938 if (to != NULL) \
939 ret = __put_user(x, to); \
940 else \
941 ret = -EFAULT; \
942 } \
943 ret; \
944 })
945
946 static inline int vhost_put_avail_event(struct vhost_virtqueue *vq)
947 {
948 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx),
949 vhost_avail_event(vq));
950 }
951
952 static inline int vhost_put_used(struct vhost_virtqueue *vq,
953 struct vring_used_elem *head, int idx,
954 int count)
955 {
956 return vhost_copy_to_user(vq, vq->used->ring + idx, head,
957 count * sizeof(*head));
958 }
959
960 static inline int vhost_put_used_flags(struct vhost_virtqueue *vq)
961
962 {
963 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags),
964 &vq->used->flags);
965 }
966
967 static inline int vhost_put_used_idx(struct vhost_virtqueue *vq)
968
969 {
970 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx),
971 &vq->used->idx);
972 }
973
974 #define vhost_get_user(vq, x, ptr, type) \
975 ({ \
976 int ret; \
977 if (!vq->iotlb) { \
978 ret = __get_user(x, ptr); \
979 } else { \
980 __typeof__(ptr) from = \
981 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
982 sizeof(*ptr), \
983 type); \
984 if (from != NULL) \
985 ret = __get_user(x, from); \
986 else \
987 ret = -EFAULT; \
988 } \
989 ret; \
990 })
991
992 #define vhost_get_avail(vq, x, ptr) \
993 vhost_get_user(vq, x, ptr, VHOST_ADDR_AVAIL)
994
995 #define vhost_get_used(vq, x, ptr) \
996 vhost_get_user(vq, x, ptr, VHOST_ADDR_USED)
997
998 static void vhost_dev_lock_vqs(struct vhost_dev *d)
999 {
1000 int i = 0;
1001 for (i = 0; i < d->nvqs; ++i)
1002 mutex_lock_nested(&d->vqs[i]->mutex, i);
1003 }
1004
1005 static void vhost_dev_unlock_vqs(struct vhost_dev *d)
1006 {
1007 int i = 0;
1008 for (i = 0; i < d->nvqs; ++i)
1009 mutex_unlock(&d->vqs[i]->mutex);
1010 }
1011
1012 static inline int vhost_get_avail_idx(struct vhost_virtqueue *vq,
1013 __virtio16 *idx)
1014 {
1015 return vhost_get_avail(vq, *idx, &vq->avail->idx);
1016 }
1017
1018 static inline int vhost_get_avail_head(struct vhost_virtqueue *vq,
1019 __virtio16 *head, int idx)
1020 {
1021 return vhost_get_avail(vq, *head,
1022 &vq->avail->ring[idx & (vq->num - 1)]);
1023 }
1024
1025 static inline int vhost_get_avail_flags(struct vhost_virtqueue *vq,
1026 __virtio16 *flags)
1027 {
1028 return vhost_get_avail(vq, *flags, &vq->avail->flags);
1029 }
1030
1031 static inline int vhost_get_used_event(struct vhost_virtqueue *vq,
1032 __virtio16 *event)
1033 {
1034 return vhost_get_avail(vq, *event, vhost_used_event(vq));
1035 }
1036
1037 static inline int vhost_get_used_idx(struct vhost_virtqueue *vq,
1038 __virtio16 *idx)
1039 {
1040 return vhost_get_used(vq, *idx, &vq->used->idx);
1041 }
1042
1043 static inline int vhost_get_desc(struct vhost_virtqueue *vq,
1044 struct vring_desc *desc, int idx)
1045 {
1046 return vhost_copy_from_user(vq, desc, vq->desc + idx, sizeof(*desc));
1047 }
1048
1049 static void vhost_iotlb_notify_vq(struct vhost_dev *d,
1050 struct vhost_iotlb_msg *msg)
1051 {
1052 struct vhost_msg_node *node, *n;
1053
1054 spin_lock(&d->iotlb_lock);
1055
1056 list_for_each_entry_safe(node, n, &d->pending_list, node) {
1057 struct vhost_iotlb_msg *vq_msg = &node->msg.iotlb;
1058 if (msg->iova <= vq_msg->iova &&
1059 msg->iova + msg->size - 1 >= vq_msg->iova &&
1060 vq_msg->type == VHOST_IOTLB_MISS) {
1061 vhost_poll_queue(&node->vq->poll);
1062 list_del(&node->node);
1063 kfree(node);
1064 }
1065 }
1066
1067 spin_unlock(&d->iotlb_lock);
1068 }
1069
1070 static bool umem_access_ok(u64 uaddr, u64 size, int access)
1071 {
1072 unsigned long a = uaddr;
1073
1074 /* Make sure 64 bit math will not overflow. */
1075 if (vhost_overflow(uaddr, size))
1076 return false;
1077
1078 if ((access & VHOST_ACCESS_RO) &&
1079 !access_ok((void __user *)a, size))
1080 return false;
1081 if ((access & VHOST_ACCESS_WO) &&
1082 !access_ok((void __user *)a, size))
1083 return false;
1084 return true;
1085 }
1086
1087 static int vhost_process_iotlb_msg(struct vhost_dev *dev,
1088 struct vhost_iotlb_msg *msg)
1089 {
1090 int ret = 0;
1091
1092 mutex_lock(&dev->mutex);
1093 vhost_dev_lock_vqs(dev);
1094 switch (msg->type) {
1095 case VHOST_IOTLB_UPDATE:
1096 if (!dev->iotlb) {
1097 ret = -EFAULT;
1098 break;
1099 }
1100 if (!umem_access_ok(msg->uaddr, msg->size, msg->perm)) {
1101 ret = -EFAULT;
1102 break;
1103 }
1104 vhost_vq_meta_reset(dev);
1105 if (vhost_iotlb_add_range(dev->iotlb, msg->iova,
1106 msg->iova + msg->size - 1,
1107 msg->uaddr, msg->perm)) {
1108 ret = -ENOMEM;
1109 break;
1110 }
1111 vhost_iotlb_notify_vq(dev, msg);
1112 break;
1113 case VHOST_IOTLB_INVALIDATE:
1114 if (!dev->iotlb) {
1115 ret = -EFAULT;
1116 break;
1117 }
1118 vhost_vq_meta_reset(dev);
1119 vhost_iotlb_del_range(dev->iotlb, msg->iova,
1120 msg->iova + msg->size - 1);
1121 break;
1122 default:
1123 ret = -EINVAL;
1124 break;
1125 }
1126
1127 vhost_dev_unlock_vqs(dev);
1128 mutex_unlock(&dev->mutex);
1129
1130 return ret;
1131 }
1132 ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
1133 struct iov_iter *from)
1134 {
1135 struct vhost_iotlb_msg msg;
1136 size_t offset;
1137 int type, ret;
1138
1139 ret = copy_from_iter(&type, sizeof(type), from);
1140 if (ret != sizeof(type)) {
1141 ret = -EINVAL;
1142 goto done;
1143 }
1144
1145 switch (type) {
1146 case VHOST_IOTLB_MSG:
1147 /* There maybe a hole after type for V1 message type,
1148 * so skip it here.
1149 */
1150 offset = offsetof(struct vhost_msg, iotlb) - sizeof(int);
1151 break;
1152 case VHOST_IOTLB_MSG_V2:
1153 offset = sizeof(__u32);
1154 break;
1155 default:
1156 ret = -EINVAL;
1157 goto done;
1158 }
1159
1160 iov_iter_advance(from, offset);
1161 ret = copy_from_iter(&msg, sizeof(msg), from);
1162 if (ret != sizeof(msg)) {
1163 ret = -EINVAL;
1164 goto done;
1165 }
1166
1167 if (dev->msg_handler)
1168 ret = dev->msg_handler(dev, &msg);
1169 else
1170 ret = vhost_process_iotlb_msg(dev, &msg);
1171 if (ret) {
1172 ret = -EFAULT;
1173 goto done;
1174 }
1175
1176 ret = (type == VHOST_IOTLB_MSG) ? sizeof(struct vhost_msg) :
1177 sizeof(struct vhost_msg_v2);
1178 done:
1179 return ret;
1180 }
1181 EXPORT_SYMBOL(vhost_chr_write_iter);
1182
1183 __poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
1184 poll_table *wait)
1185 {
1186 __poll_t mask = 0;
1187
1188 poll_wait(file, &dev->wait, wait);
1189
1190 if (!list_empty(&dev->read_list))
1191 mask |= EPOLLIN | EPOLLRDNORM;
1192
1193 return mask;
1194 }
1195 EXPORT_SYMBOL(vhost_chr_poll);
1196
1197 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
1198 int noblock)
1199 {
1200 DEFINE_WAIT(wait);
1201 struct vhost_msg_node *node;
1202 ssize_t ret = 0;
1203 unsigned size = sizeof(struct vhost_msg);
1204
1205 if (iov_iter_count(to) < size)
1206 return 0;
1207
1208 while (1) {
1209 if (!noblock)
1210 prepare_to_wait(&dev->wait, &wait,
1211 TASK_INTERRUPTIBLE);
1212
1213 node = vhost_dequeue_msg(dev, &dev->read_list);
1214 if (node)
1215 break;
1216 if (noblock) {
1217 ret = -EAGAIN;
1218 break;
1219 }
1220 if (signal_pending(current)) {
1221 ret = -ERESTARTSYS;
1222 break;
1223 }
1224 if (!dev->iotlb) {
1225 ret = -EBADFD;
1226 break;
1227 }
1228
1229 schedule();
1230 }
1231
1232 if (!noblock)
1233 finish_wait(&dev->wait, &wait);
1234
1235 if (node) {
1236 struct vhost_iotlb_msg *msg;
1237 void *start = &node->msg;
1238
1239 switch (node->msg.type) {
1240 case VHOST_IOTLB_MSG:
1241 size = sizeof(node->msg);
1242 msg = &node->msg.iotlb;
1243 break;
1244 case VHOST_IOTLB_MSG_V2:
1245 size = sizeof(node->msg_v2);
1246 msg = &node->msg_v2.iotlb;
1247 break;
1248 default:
1249 BUG();
1250 break;
1251 }
1252
1253 ret = copy_to_iter(start, size, to);
1254 if (ret != size || msg->type != VHOST_IOTLB_MISS) {
1255 kfree(node);
1256 return ret;
1257 }
1258 vhost_enqueue_msg(dev, &dev->pending_list, node);
1259 }
1260
1261 return ret;
1262 }
1263 EXPORT_SYMBOL_GPL(vhost_chr_read_iter);
1264
1265 static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access)
1266 {
1267 struct vhost_dev *dev = vq->dev;
1268 struct vhost_msg_node *node;
1269 struct vhost_iotlb_msg *msg;
1270 bool v2 = vhost_backend_has_feature(vq, VHOST_BACKEND_F_IOTLB_MSG_V2);
1271
1272 node = vhost_new_msg(vq, v2 ? VHOST_IOTLB_MSG_V2 : VHOST_IOTLB_MSG);
1273 if (!node)
1274 return -ENOMEM;
1275
1276 if (v2) {
1277 node->msg_v2.type = VHOST_IOTLB_MSG_V2;
1278 msg = &node->msg_v2.iotlb;
1279 } else {
1280 msg = &node->msg.iotlb;
1281 }
1282
1283 msg->type = VHOST_IOTLB_MISS;
1284 msg->iova = iova;
1285 msg->perm = access;
1286
1287 vhost_enqueue_msg(dev, &dev->read_list, node);
1288
1289 return 0;
1290 }
1291
1292 static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
1293 vring_desc_t __user *desc,
1294 vring_avail_t __user *avail,
1295 vring_used_t __user *used)
1296
1297 {
1298 /* If an IOTLB device is present, the vring addresses are
1299 * GIOVAs. Access validation occurs at prefetch time. */
1300 if (vq->iotlb)
1301 return true;
1302
1303 return access_ok(desc, vhost_get_desc_size(vq, num)) &&
1304 access_ok(avail, vhost_get_avail_size(vq, num)) &&
1305 access_ok(used, vhost_get_used_size(vq, num));
1306 }
1307
1308 static void vhost_vq_meta_update(struct vhost_virtqueue *vq,
1309 const struct vhost_iotlb_map *map,
1310 int type)
1311 {
1312 int access = (type == VHOST_ADDR_USED) ?
1313 VHOST_ACCESS_WO : VHOST_ACCESS_RO;
1314
1315 if (likely(map->perm & access))
1316 vq->meta_iotlb[type] = map;
1317 }
1318
1319 static bool iotlb_access_ok(struct vhost_virtqueue *vq,
1320 int access, u64 addr, u64 len, int type)
1321 {
1322 const struct vhost_iotlb_map *map;
1323 struct vhost_iotlb *umem = vq->iotlb;
1324 u64 s = 0, size, orig_addr = addr, last = addr + len - 1;
1325
1326 if (vhost_vq_meta_fetch(vq, addr, len, type))
1327 return true;
1328
1329 while (len > s) {
1330 map = vhost_iotlb_itree_first(umem, addr, last);
1331 if (map == NULL || map->start > addr) {
1332 vhost_iotlb_miss(vq, addr, access);
1333 return false;
1334 } else if (!(map->perm & access)) {
1335 /* Report the possible access violation by
1336 * request another translation from userspace.
1337 */
1338 return false;
1339 }
1340
1341 size = map->size - addr + map->start;
1342
1343 if (orig_addr == addr && size >= len)
1344 vhost_vq_meta_update(vq, map, type);
1345
1346 s += size;
1347 addr += size;
1348 }
1349
1350 return true;
1351 }
1352
1353 int vq_meta_prefetch(struct vhost_virtqueue *vq)
1354 {
1355 unsigned int num = vq->num;
1356
1357 if (!vq->iotlb)
1358 return 1;
1359
1360 return iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->desc,
1361 vhost_get_desc_size(vq, num), VHOST_ADDR_DESC) &&
1362 iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->avail,
1363 vhost_get_avail_size(vq, num),
1364 VHOST_ADDR_AVAIL) &&
1365 iotlb_access_ok(vq, VHOST_MAP_WO, (u64)(uintptr_t)vq->used,
1366 vhost_get_used_size(vq, num), VHOST_ADDR_USED);
1367 }
1368 EXPORT_SYMBOL_GPL(vq_meta_prefetch);
1369
1370 /* Can we log writes? */
1371 /* Caller should have device mutex but not vq mutex */
1372 bool vhost_log_access_ok(struct vhost_dev *dev)
1373 {
1374 return memory_access_ok(dev, dev->umem, 1);
1375 }
1376 EXPORT_SYMBOL_GPL(vhost_log_access_ok);
1377
1378 static bool vq_log_used_access_ok(struct vhost_virtqueue *vq,
1379 void __user *log_base,
1380 bool log_used,
1381 u64 log_addr)
1382 {
1383 /* If an IOTLB device is present, log_addr is a GIOVA that
1384 * will never be logged by log_used(). */
1385 if (vq->iotlb)
1386 return true;
1387
1388 return !log_used || log_access_ok(log_base, log_addr,
1389 vhost_get_used_size(vq, vq->num));
1390 }
1391
1392 /* Verify access for write logging. */
1393 /* Caller should have vq mutex and device mutex */
1394 static bool vq_log_access_ok(struct vhost_virtqueue *vq,
1395 void __user *log_base)
1396 {
1397 return vq_memory_access_ok(log_base, vq->umem,
1398 vhost_has_feature(vq, VHOST_F_LOG_ALL)) &&
1399 vq_log_used_access_ok(vq, log_base, vq->log_used, vq->log_addr);
1400 }
1401
1402 /* Can we start vq? */
1403 /* Caller should have vq mutex and device mutex */
1404 bool vhost_vq_access_ok(struct vhost_virtqueue *vq)
1405 {
1406 if (!vq_log_access_ok(vq, vq->log_base))
1407 return false;
1408
1409 return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used);
1410 }
1411 EXPORT_SYMBOL_GPL(vhost_vq_access_ok);
1412
1413 static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
1414 {
1415 struct vhost_memory mem, *newmem;
1416 struct vhost_memory_region *region;
1417 struct vhost_iotlb *newumem, *oldumem;
1418 unsigned long size = offsetof(struct vhost_memory, regions);
1419 int i;
1420
1421 if (copy_from_user(&mem, m, size))
1422 return -EFAULT;
1423 if (mem.padding)
1424 return -EOPNOTSUPP;
1425 if (mem.nregions > max_mem_regions)
1426 return -E2BIG;
1427 newmem = kvzalloc(struct_size(newmem, regions, mem.nregions),
1428 GFP_KERNEL);
1429 if (!newmem)
1430 return -ENOMEM;
1431
1432 memcpy(newmem, &mem, size);
1433 if (copy_from_user(newmem->regions, m->regions,
1434 flex_array_size(newmem, regions, mem.nregions))) {
1435 kvfree(newmem);
1436 return -EFAULT;
1437 }
1438
1439 newumem = iotlb_alloc();
1440 if (!newumem) {
1441 kvfree(newmem);
1442 return -ENOMEM;
1443 }
1444
1445 for (region = newmem->regions;
1446 region < newmem->regions + mem.nregions;
1447 region++) {
1448 if (vhost_iotlb_add_range(newumem,
1449 region->guest_phys_addr,
1450 region->guest_phys_addr +
1451 region->memory_size - 1,
1452 region->userspace_addr,
1453 VHOST_MAP_RW))
1454 goto err;
1455 }
1456
1457 if (!memory_access_ok(d, newumem, 0))
1458 goto err;
1459
1460 oldumem = d->umem;
1461 d->umem = newumem;
1462
1463 /* All memory accesses are done under some VQ mutex. */
1464 for (i = 0; i < d->nvqs; ++i) {
1465 mutex_lock(&d->vqs[i]->mutex);
1466 d->vqs[i]->umem = newumem;
1467 mutex_unlock(&d->vqs[i]->mutex);
1468 }
1469
1470 kvfree(newmem);
1471 vhost_iotlb_free(oldumem);
1472 return 0;
1473
1474 err:
1475 vhost_iotlb_free(newumem);
1476 kvfree(newmem);
1477 return -EFAULT;
1478 }
1479
1480 static long vhost_vring_set_num(struct vhost_dev *d,
1481 struct vhost_virtqueue *vq,
1482 void __user *argp)
1483 {
1484 struct vhost_vring_state s;
1485
1486 /* Resizing ring with an active backend?
1487 * You don't want to do that. */
1488 if (vq->private_data)
1489 return -EBUSY;
1490
1491 if (copy_from_user(&s, argp, sizeof s))
1492 return -EFAULT;
1493
1494 if (!s.num || s.num > 0xffff || (s.num & (s.num - 1)))
1495 return -EINVAL;
1496 vq->num = s.num;
1497
1498 return 0;
1499 }
1500
1501 static long vhost_vring_set_addr(struct vhost_dev *d,
1502 struct vhost_virtqueue *vq,
1503 void __user *argp)
1504 {
1505 struct vhost_vring_addr a;
1506
1507 if (copy_from_user(&a, argp, sizeof a))
1508 return -EFAULT;
1509 if (a.flags & ~(0x1 << VHOST_VRING_F_LOG))
1510 return -EOPNOTSUPP;
1511
1512 /* For 32bit, verify that the top 32bits of the user
1513 data are set to zero. */
1514 if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr ||
1515 (u64)(unsigned long)a.used_user_addr != a.used_user_addr ||
1516 (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr)
1517 return -EFAULT;
1518
1519 /* Make sure it's safe to cast pointers to vring types. */
1520 BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE);
1521 BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE);
1522 if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) ||
1523 (a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) ||
1524 (a.log_guest_addr & (VRING_USED_ALIGN_SIZE - 1)))
1525 return -EINVAL;
1526
1527 /* We only verify access here if backend is configured.
1528 * If it is not, we don't as size might not have been setup.
1529 * We will verify when backend is configured. */
1530 if (vq->private_data) {
1531 if (!vq_access_ok(vq, vq->num,
1532 (void __user *)(unsigned long)a.desc_user_addr,
1533 (void __user *)(unsigned long)a.avail_user_addr,
1534 (void __user *)(unsigned long)a.used_user_addr))
1535 return -EINVAL;
1536
1537 /* Also validate log access for used ring if enabled. */
1538 if (!vq_log_used_access_ok(vq, vq->log_base,
1539 a.flags & (0x1 << VHOST_VRING_F_LOG),
1540 a.log_guest_addr))
1541 return -EINVAL;
1542 }
1543
1544 vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG));
1545 vq->desc = (void __user *)(unsigned long)a.desc_user_addr;
1546 vq->avail = (void __user *)(unsigned long)a.avail_user_addr;
1547 vq->log_addr = a.log_guest_addr;
1548 vq->used = (void __user *)(unsigned long)a.used_user_addr;
1549
1550 return 0;
1551 }
1552
1553 static long vhost_vring_set_num_addr(struct vhost_dev *d,
1554 struct vhost_virtqueue *vq,
1555 unsigned int ioctl,
1556 void __user *argp)
1557 {
1558 long r;
1559
1560 mutex_lock(&vq->mutex);
1561
1562 switch (ioctl) {
1563 case VHOST_SET_VRING_NUM:
1564 r = vhost_vring_set_num(d, vq, argp);
1565 break;
1566 case VHOST_SET_VRING_ADDR:
1567 r = vhost_vring_set_addr(d, vq, argp);
1568 break;
1569 default:
1570 BUG();
1571 }
1572
1573 mutex_unlock(&vq->mutex);
1574
1575 return r;
1576 }
1577 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
1578 {
1579 struct file *eventfp, *filep = NULL;
1580 bool pollstart = false, pollstop = false;
1581 struct eventfd_ctx *ctx = NULL;
1582 u32 __user *idxp = argp;
1583 struct vhost_virtqueue *vq;
1584 struct vhost_vring_state s;
1585 struct vhost_vring_file f;
1586 u32 idx;
1587 long r;
1588
1589 r = get_user(idx, idxp);
1590 if (r < 0)
1591 return r;
1592 if (idx >= d->nvqs)
1593 return -ENOBUFS;
1594
1595 idx = array_index_nospec(idx, d->nvqs);
1596 vq = d->vqs[idx];
1597
1598 if (ioctl == VHOST_SET_VRING_NUM ||
1599 ioctl == VHOST_SET_VRING_ADDR) {
1600 return vhost_vring_set_num_addr(d, vq, ioctl, argp);
1601 }
1602
1603 mutex_lock(&vq->mutex);
1604
1605 switch (ioctl) {
1606 case VHOST_SET_VRING_BASE:
1607 /* Moving base with an active backend?
1608 * You don't want to do that. */
1609 if (vq->private_data) {
1610 r = -EBUSY;
1611 break;
1612 }
1613 if (copy_from_user(&s, argp, sizeof s)) {
1614 r = -EFAULT;
1615 break;
1616 }
1617 if (s.num > 0xffff) {
1618 r = -EINVAL;
1619 break;
1620 }
1621 vq->last_avail_idx = s.num;
1622 /* Forget the cached index value. */
1623 vq->avail_idx = vq->last_avail_idx;
1624 break;
1625 case VHOST_GET_VRING_BASE:
1626 s.index = idx;
1627 s.num = vq->last_avail_idx;
1628 if (copy_to_user(argp, &s, sizeof s))
1629 r = -EFAULT;
1630 break;
1631 case VHOST_SET_VRING_KICK:
1632 if (copy_from_user(&f, argp, sizeof f)) {
1633 r = -EFAULT;
1634 break;
1635 }
1636 eventfp = f.fd == VHOST_FILE_UNBIND ? NULL : eventfd_fget(f.fd);
1637 if (IS_ERR(eventfp)) {
1638 r = PTR_ERR(eventfp);
1639 break;
1640 }
1641 if (eventfp != vq->kick) {
1642 pollstop = (filep = vq->kick) != NULL;
1643 pollstart = (vq->kick = eventfp) != NULL;
1644 } else
1645 filep = eventfp;
1646 break;
1647 case VHOST_SET_VRING_CALL:
1648 if (copy_from_user(&f, argp, sizeof f)) {
1649 r = -EFAULT;
1650 break;
1651 }
1652 ctx = f.fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(f.fd);
1653 if (IS_ERR(ctx)) {
1654 r = PTR_ERR(ctx);
1655 break;
1656 }
1657
1658 swap(ctx, vq->call_ctx.ctx);
1659 break;
1660 case VHOST_SET_VRING_ERR:
1661 if (copy_from_user(&f, argp, sizeof f)) {
1662 r = -EFAULT;
1663 break;
1664 }
1665 ctx = f.fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(f.fd);
1666 if (IS_ERR(ctx)) {
1667 r = PTR_ERR(ctx);
1668 break;
1669 }
1670 swap(ctx, vq->error_ctx);
1671 break;
1672 case VHOST_SET_VRING_ENDIAN:
1673 r = vhost_set_vring_endian(vq, argp);
1674 break;
1675 case VHOST_GET_VRING_ENDIAN:
1676 r = vhost_get_vring_endian(vq, idx, argp);
1677 break;
1678 case VHOST_SET_VRING_BUSYLOOP_TIMEOUT:
1679 if (copy_from_user(&s, argp, sizeof(s))) {
1680 r = -EFAULT;
1681 break;
1682 }
1683 vq->busyloop_timeout = s.num;
1684 break;
1685 case VHOST_GET_VRING_BUSYLOOP_TIMEOUT:
1686 s.index = idx;
1687 s.num = vq->busyloop_timeout;
1688 if (copy_to_user(argp, &s, sizeof(s)))
1689 r = -EFAULT;
1690 break;
1691 default:
1692 r = -ENOIOCTLCMD;
1693 }
1694
1695 if (pollstop && vq->handle_kick)
1696 vhost_poll_stop(&vq->poll);
1697
1698 if (!IS_ERR_OR_NULL(ctx))
1699 eventfd_ctx_put(ctx);
1700 if (filep)
1701 fput(filep);
1702
1703 if (pollstart && vq->handle_kick)
1704 r = vhost_poll_start(&vq->poll, vq->kick);
1705
1706 mutex_unlock(&vq->mutex);
1707
1708 if (pollstop && vq->handle_kick)
1709 vhost_poll_flush(&vq->poll);
1710 return r;
1711 }
1712 EXPORT_SYMBOL_GPL(vhost_vring_ioctl);
1713
1714 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled)
1715 {
1716 struct vhost_iotlb *niotlb, *oiotlb;
1717 int i;
1718
1719 niotlb = iotlb_alloc();
1720 if (!niotlb)
1721 return -ENOMEM;
1722
1723 oiotlb = d->iotlb;
1724 d->iotlb = niotlb;
1725
1726 for (i = 0; i < d->nvqs; ++i) {
1727 struct vhost_virtqueue *vq = d->vqs[i];
1728
1729 mutex_lock(&vq->mutex);
1730 vq->iotlb = niotlb;
1731 __vhost_vq_meta_reset(vq);
1732 mutex_unlock(&vq->mutex);
1733 }
1734
1735 vhost_iotlb_free(oiotlb);
1736
1737 return 0;
1738 }
1739 EXPORT_SYMBOL_GPL(vhost_init_device_iotlb);
1740
1741 /* Caller must have device mutex */
1742 long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
1743 {
1744 struct eventfd_ctx *ctx;
1745 u64 p;
1746 long r;
1747 int i, fd;
1748
1749 /* If you are not the owner, you can become one */
1750 if (ioctl == VHOST_SET_OWNER) {
1751 r = vhost_dev_set_owner(d);
1752 goto done;
1753 }
1754
1755 /* You must be the owner to do anything else */
1756 r = vhost_dev_check_owner(d);
1757 if (r)
1758 goto done;
1759
1760 switch (ioctl) {
1761 case VHOST_SET_MEM_TABLE:
1762 r = vhost_set_memory(d, argp);
1763 break;
1764 case VHOST_SET_LOG_BASE:
1765 if (copy_from_user(&p, argp, sizeof p)) {
1766 r = -EFAULT;
1767 break;
1768 }
1769 if ((u64)(unsigned long)p != p) {
1770 r = -EFAULT;
1771 break;
1772 }
1773 for (i = 0; i < d->nvqs; ++i) {
1774 struct vhost_virtqueue *vq;
1775 void __user *base = (void __user *)(unsigned long)p;
1776 vq = d->vqs[i];
1777 mutex_lock(&vq->mutex);
1778 /* If ring is inactive, will check when it's enabled. */
1779 if (vq->private_data && !vq_log_access_ok(vq, base))
1780 r = -EFAULT;
1781 else
1782 vq->log_base = base;
1783 mutex_unlock(&vq->mutex);
1784 }
1785 break;
1786 case VHOST_SET_LOG_FD:
1787 r = get_user(fd, (int __user *)argp);
1788 if (r < 0)
1789 break;
1790 ctx = fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(fd);
1791 if (IS_ERR(ctx)) {
1792 r = PTR_ERR(ctx);
1793 break;
1794 }
1795 swap(ctx, d->log_ctx);
1796 for (i = 0; i < d->nvqs; ++i) {
1797 mutex_lock(&d->vqs[i]->mutex);
1798 d->vqs[i]->log_ctx = d->log_ctx;
1799 mutex_unlock(&d->vqs[i]->mutex);
1800 }
1801 if (ctx)
1802 eventfd_ctx_put(ctx);
1803 break;
1804 default:
1805 r = -ENOIOCTLCMD;
1806 break;
1807 }
1808 done:
1809 return r;
1810 }
1811 EXPORT_SYMBOL_GPL(vhost_dev_ioctl);
1812
1813 /* TODO: This is really inefficient. We need something like get_user()
1814 * (instruction directly accesses the data, with an exception table entry
1815 * returning -EFAULT). See Documentation/x86/exception-tables.rst.
1816 */
1817 static int set_bit_to_user(int nr, void __user *addr)
1818 {
1819 unsigned long log = (unsigned long)addr;
1820 struct page *page;
1821 void *base;
1822 int bit = nr + (log % PAGE_SIZE) * 8;
1823 int r;
1824
1825 r = pin_user_pages_fast(log, 1, FOLL_WRITE, &page);
1826 if (r < 0)
1827 return r;
1828 BUG_ON(r != 1);
1829 base = kmap_atomic(page);
1830 set_bit(bit, base);
1831 kunmap_atomic(base);
1832 unpin_user_pages_dirty_lock(&page, 1, true);
1833 return 0;
1834 }
1835
1836 static int log_write(void __user *log_base,
1837 u64 write_address, u64 write_length)
1838 {
1839 u64 write_page = write_address / VHOST_PAGE_SIZE;
1840 int r;
1841
1842 if (!write_length)
1843 return 0;
1844 write_length += write_address % VHOST_PAGE_SIZE;
1845 for (;;) {
1846 u64 base = (u64)(unsigned long)log_base;
1847 u64 log = base + write_page / 8;
1848 int bit = write_page % 8;
1849 if ((u64)(unsigned long)log != log)
1850 return -EFAULT;
1851 r = set_bit_to_user(bit, (void __user *)(unsigned long)log);
1852 if (r < 0)
1853 return r;
1854 if (write_length <= VHOST_PAGE_SIZE)
1855 break;
1856 write_length -= VHOST_PAGE_SIZE;
1857 write_page += 1;
1858 }
1859 return r;
1860 }
1861
1862 static int log_write_hva(struct vhost_virtqueue *vq, u64 hva, u64 len)
1863 {
1864 struct vhost_iotlb *umem = vq->umem;
1865 struct vhost_iotlb_map *u;
1866 u64 start, end, l, min;
1867 int r;
1868 bool hit = false;
1869
1870 while (len) {
1871 min = len;
1872 /* More than one GPAs can be mapped into a single HVA. So
1873 * iterate all possible umems here to be safe.
1874 */
1875 list_for_each_entry(u, &umem->list, link) {
1876 if (u->addr > hva - 1 + len ||
1877 u->addr - 1 + u->size < hva)
1878 continue;
1879 start = max(u->addr, hva);
1880 end = min(u->addr - 1 + u->size, hva - 1 + len);
1881 l = end - start + 1;
1882 r = log_write(vq->log_base,
1883 u->start + start - u->addr,
1884 l);
1885 if (r < 0)
1886 return r;
1887 hit = true;
1888 min = min(l, min);
1889 }
1890
1891 if (!hit)
1892 return -EFAULT;
1893
1894 len -= min;
1895 hva += min;
1896 }
1897
1898 return 0;
1899 }
1900
1901 static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len)
1902 {
1903 struct iovec *iov = vq->log_iov;
1904 int i, ret;
1905
1906 if (!vq->iotlb)
1907 return log_write(vq->log_base, vq->log_addr + used_offset, len);
1908
1909 ret = translate_desc(vq, (uintptr_t)vq->used + used_offset,
1910 len, iov, 64, VHOST_ACCESS_WO);
1911 if (ret < 0)
1912 return ret;
1913
1914 for (i = 0; i < ret; i++) {
1915 ret = log_write_hva(vq, (uintptr_t)iov[i].iov_base,
1916 iov[i].iov_len);
1917 if (ret)
1918 return ret;
1919 }
1920
1921 return 0;
1922 }
1923
1924 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
1925 unsigned int log_num, u64 len, struct iovec *iov, int count)
1926 {
1927 int i, r;
1928
1929 /* Make sure data written is seen before log. */
1930 smp_wmb();
1931
1932 if (vq->iotlb) {
1933 for (i = 0; i < count; i++) {
1934 r = log_write_hva(vq, (uintptr_t)iov[i].iov_base,
1935 iov[i].iov_len);
1936 if (r < 0)
1937 return r;
1938 }
1939 return 0;
1940 }
1941
1942 for (i = 0; i < log_num; ++i) {
1943 u64 l = min(log[i].len, len);
1944 r = log_write(vq->log_base, log[i].addr, l);
1945 if (r < 0)
1946 return r;
1947 len -= l;
1948 if (!len) {
1949 if (vq->log_ctx)
1950 eventfd_signal(vq->log_ctx, 1);
1951 return 0;
1952 }
1953 }
1954 /* Length written exceeds what we have stored. This is a bug. */
1955 BUG();
1956 return 0;
1957 }
1958 EXPORT_SYMBOL_GPL(vhost_log_write);
1959
1960 static int vhost_update_used_flags(struct vhost_virtqueue *vq)
1961 {
1962 void __user *used;
1963 if (vhost_put_used_flags(vq))
1964 return -EFAULT;
1965 if (unlikely(vq->log_used)) {
1966 /* Make sure the flag is seen before log. */
1967 smp_wmb();
1968 /* Log used flag write. */
1969 used = &vq->used->flags;
1970 log_used(vq, (used - (void __user *)vq->used),
1971 sizeof vq->used->flags);
1972 if (vq->log_ctx)
1973 eventfd_signal(vq->log_ctx, 1);
1974 }
1975 return 0;
1976 }
1977
1978 static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
1979 {
1980 if (vhost_put_avail_event(vq))
1981 return -EFAULT;
1982 if (unlikely(vq->log_used)) {
1983 void __user *used;
1984 /* Make sure the event is seen before log. */
1985 smp_wmb();
1986 /* Log avail event write */
1987 used = vhost_avail_event(vq);
1988 log_used(vq, (used - (void __user *)vq->used),
1989 sizeof *vhost_avail_event(vq));
1990 if (vq->log_ctx)
1991 eventfd_signal(vq->log_ctx, 1);
1992 }
1993 return 0;
1994 }
1995
1996 int vhost_vq_init_access(struct vhost_virtqueue *vq)
1997 {
1998 __virtio16 last_used_idx;
1999 int r;
2000 bool is_le = vq->is_le;
2001
2002 if (!vq->private_data)
2003 return 0;
2004
2005 vhost_init_is_le(vq);
2006
2007 r = vhost_update_used_flags(vq);
2008 if (r)
2009 goto err;
2010 vq->signalled_used_valid = false;
2011 if (!vq->iotlb &&
2012 !access_ok(&vq->used->idx, sizeof vq->used->idx)) {
2013 r = -EFAULT;
2014 goto err;
2015 }
2016 r = vhost_get_used_idx(vq, &last_used_idx);
2017 if (r) {
2018 vq_err(vq, "Can't access used idx at %p\n",
2019 &vq->used->idx);
2020 goto err;
2021 }
2022 vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx);
2023 return 0;
2024
2025 err:
2026 vq->is_le = is_le;
2027 return r;
2028 }
2029 EXPORT_SYMBOL_GPL(vhost_vq_init_access);
2030
2031 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
2032 struct iovec iov[], int iov_size, int access)
2033 {
2034 const struct vhost_iotlb_map *map;
2035 struct vhost_dev *dev = vq->dev;
2036 struct vhost_iotlb *umem = dev->iotlb ? dev->iotlb : dev->umem;
2037 struct iovec *_iov;
2038 u64 s = 0;
2039 int ret = 0;
2040
2041 while ((u64)len > s) {
2042 u64 size;
2043 if (unlikely(ret >= iov_size)) {
2044 ret = -ENOBUFS;
2045 break;
2046 }
2047
2048 map = vhost_iotlb_itree_first(umem, addr, addr + len - 1);
2049 if (map == NULL || map->start > addr) {
2050 if (umem != dev->iotlb) {
2051 ret = -EFAULT;
2052 break;
2053 }
2054 ret = -EAGAIN;
2055 break;
2056 } else if (!(map->perm & access)) {
2057 ret = -EPERM;
2058 break;
2059 }
2060
2061 _iov = iov + ret;
2062 size = map->size - addr + map->start;
2063 _iov->iov_len = min((u64)len - s, size);
2064 _iov->iov_base = (void __user *)(unsigned long)
2065 (map->addr + addr - map->start);
2066 s += size;
2067 addr += size;
2068 ++ret;
2069 }
2070
2071 if (ret == -EAGAIN)
2072 vhost_iotlb_miss(vq, addr, access);
2073 return ret;
2074 }
2075
2076 /* Each buffer in the virtqueues is actually a chain of descriptors. This
2077 * function returns the next descriptor in the chain,
2078 * or -1U if we're at the end. */
2079 static unsigned next_desc(struct vhost_virtqueue *vq, struct vring_desc *desc)
2080 {
2081 unsigned int next;
2082
2083 /* If this descriptor says it doesn't chain, we're done. */
2084 if (!(desc->flags & cpu_to_vhost16(vq, VRING_DESC_F_NEXT)))
2085 return -1U;
2086
2087 /* Check they're not leading us off end of descriptors. */
2088 next = vhost16_to_cpu(vq, READ_ONCE(desc->next));
2089 return next;
2090 }
2091
2092 static int get_indirect(struct vhost_virtqueue *vq,
2093 struct iovec iov[], unsigned int iov_size,
2094 unsigned int *out_num, unsigned int *in_num,
2095 struct vhost_log *log, unsigned int *log_num,
2096 struct vring_desc *indirect)
2097 {
2098 struct vring_desc desc;
2099 unsigned int i = 0, count, found = 0;
2100 u32 len = vhost32_to_cpu(vq, indirect->len);
2101 struct iov_iter from;
2102 int ret, access;
2103
2104 /* Sanity check */
2105 if (unlikely(len % sizeof desc)) {
2106 vq_err(vq, "Invalid length in indirect descriptor: "
2107 "len 0x%llx not multiple of 0x%zx\n",
2108 (unsigned long long)len,
2109 sizeof desc);
2110 return -EINVAL;
2111 }
2112
2113 ret = translate_desc(vq, vhost64_to_cpu(vq, indirect->addr), len, vq->indirect,
2114 UIO_MAXIOV, VHOST_ACCESS_RO);
2115 if (unlikely(ret < 0)) {
2116 if (ret != -EAGAIN)
2117 vq_err(vq, "Translation failure %d in indirect.\n", ret);
2118 return ret;
2119 }
2120 iov_iter_init(&from, READ, vq->indirect, ret, len);
2121 count = len / sizeof desc;
2122 /* Buffers are chained via a 16 bit next field, so
2123 * we can have at most 2^16 of these. */
2124 if (unlikely(count > USHRT_MAX + 1)) {
2125 vq_err(vq, "Indirect buffer length too big: %d\n",
2126 indirect->len);
2127 return -E2BIG;
2128 }
2129
2130 do {
2131 unsigned iov_count = *in_num + *out_num;
2132 if (unlikely(++found > count)) {
2133 vq_err(vq, "Loop detected: last one at %u "
2134 "indirect size %u\n",
2135 i, count);
2136 return -EINVAL;
2137 }
2138 if (unlikely(!copy_from_iter_full(&desc, sizeof(desc), &from))) {
2139 vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
2140 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
2141 return -EINVAL;
2142 }
2143 if (unlikely(desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT))) {
2144 vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n",
2145 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
2146 return -EINVAL;
2147 }
2148
2149 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
2150 access = VHOST_ACCESS_WO;
2151 else
2152 access = VHOST_ACCESS_RO;
2153
2154 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
2155 vhost32_to_cpu(vq, desc.len), iov + iov_count,
2156 iov_size - iov_count, access);
2157 if (unlikely(ret < 0)) {
2158 if (ret != -EAGAIN)
2159 vq_err(vq, "Translation failure %d indirect idx %d\n",
2160 ret, i);
2161 return ret;
2162 }
2163 /* If this is an input descriptor, increment that count. */
2164 if (access == VHOST_ACCESS_WO) {
2165 *in_num += ret;
2166 if (unlikely(log && ret)) {
2167 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
2168 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
2169 ++*log_num;
2170 }
2171 } else {
2172 /* If it's an output descriptor, they're all supposed
2173 * to come before any input descriptors. */
2174 if (unlikely(*in_num)) {
2175 vq_err(vq, "Indirect descriptor "
2176 "has out after in: idx %d\n", i);
2177 return -EINVAL;
2178 }
2179 *out_num += ret;
2180 }
2181 } while ((i = next_desc(vq, &desc)) != -1);
2182 return 0;
2183 }
2184
2185 /* This looks in the virtqueue and for the first available buffer, and converts
2186 * it to an iovec for convenient access. Since descriptors consist of some
2187 * number of output then some number of input descriptors, it's actually two
2188 * iovecs, but we pack them into one and note how many of each there were.
2189 *
2190 * This function returns the descriptor number found, or vq->num (which is
2191 * never a valid descriptor number) if none was found. A negative code is
2192 * returned on error. */
2193 int vhost_get_vq_desc(struct vhost_virtqueue *vq,
2194 struct iovec iov[], unsigned int iov_size,
2195 unsigned int *out_num, unsigned int *in_num,
2196 struct vhost_log *log, unsigned int *log_num)
2197 {
2198 struct vring_desc desc;
2199 unsigned int i, head, found = 0;
2200 u16 last_avail_idx;
2201 __virtio16 avail_idx;
2202 __virtio16 ring_head;
2203 int ret, access;
2204
2205 /* Check it isn't doing very strange things with descriptor numbers. */
2206 last_avail_idx = vq->last_avail_idx;
2207
2208 if (vq->avail_idx == vq->last_avail_idx) {
2209 if (unlikely(vhost_get_avail_idx(vq, &avail_idx))) {
2210 vq_err(vq, "Failed to access avail idx at %p\n",
2211 &vq->avail->idx);
2212 return -EFAULT;
2213 }
2214 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2215
2216 if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) {
2217 vq_err(vq, "Guest moved used index from %u to %u",
2218 last_avail_idx, vq->avail_idx);
2219 return -EFAULT;
2220 }
2221
2222 /* If there's nothing new since last we looked, return
2223 * invalid.
2224 */
2225 if (vq->avail_idx == last_avail_idx)
2226 return vq->num;
2227
2228 /* Only get avail ring entries after they have been
2229 * exposed by guest.
2230 */
2231 smp_rmb();
2232 }
2233
2234 /* Grab the next descriptor number they're advertising, and increment
2235 * the index we've seen. */
2236 if (unlikely(vhost_get_avail_head(vq, &ring_head, last_avail_idx))) {
2237 vq_err(vq, "Failed to read head: idx %d address %p\n",
2238 last_avail_idx,
2239 &vq->avail->ring[last_avail_idx % vq->num]);
2240 return -EFAULT;
2241 }
2242
2243 head = vhost16_to_cpu(vq, ring_head);
2244
2245 /* If their number is silly, that's an error. */
2246 if (unlikely(head >= vq->num)) {
2247 vq_err(vq, "Guest says index %u > %u is available",
2248 head, vq->num);
2249 return -EINVAL;
2250 }
2251
2252 /* When we start there are none of either input nor output. */
2253 *out_num = *in_num = 0;
2254 if (unlikely(log))
2255 *log_num = 0;
2256
2257 i = head;
2258 do {
2259 unsigned iov_count = *in_num + *out_num;
2260 if (unlikely(i >= vq->num)) {
2261 vq_err(vq, "Desc index is %u > %u, head = %u",
2262 i, vq->num, head);
2263 return -EINVAL;
2264 }
2265 if (unlikely(++found > vq->num)) {
2266 vq_err(vq, "Loop detected: last one at %u "
2267 "vq size %u head %u\n",
2268 i, vq->num, head);
2269 return -EINVAL;
2270 }
2271 ret = vhost_get_desc(vq, &desc, i);
2272 if (unlikely(ret)) {
2273 vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
2274 i, vq->desc + i);
2275 return -EFAULT;
2276 }
2277 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT)) {
2278 ret = get_indirect(vq, iov, iov_size,
2279 out_num, in_num,
2280 log, log_num, &desc);
2281 if (unlikely(ret < 0)) {
2282 if (ret != -EAGAIN)
2283 vq_err(vq, "Failure detected "
2284 "in indirect descriptor at idx %d\n", i);
2285 return ret;
2286 }
2287 continue;
2288 }
2289
2290 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
2291 access = VHOST_ACCESS_WO;
2292 else
2293 access = VHOST_ACCESS_RO;
2294 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
2295 vhost32_to_cpu(vq, desc.len), iov + iov_count,
2296 iov_size - iov_count, access);
2297 if (unlikely(ret < 0)) {
2298 if (ret != -EAGAIN)
2299 vq_err(vq, "Translation failure %d descriptor idx %d\n",
2300 ret, i);
2301 return ret;
2302 }
2303 if (access == VHOST_ACCESS_WO) {
2304 /* If this is an input descriptor,
2305 * increment that count. */
2306 *in_num += ret;
2307 if (unlikely(log && ret)) {
2308 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
2309 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
2310 ++*log_num;
2311 }
2312 } else {
2313 /* If it's an output descriptor, they're all supposed
2314 * to come before any input descriptors. */
2315 if (unlikely(*in_num)) {
2316 vq_err(vq, "Descriptor has out after in: "
2317 "idx %d\n", i);
2318 return -EINVAL;
2319 }
2320 *out_num += ret;
2321 }
2322 } while ((i = next_desc(vq, &desc)) != -1);
2323
2324 /* On success, increment avail index. */
2325 vq->last_avail_idx++;
2326
2327 /* Assume notifications from guest are disabled at this point,
2328 * if they aren't we would need to update avail_event index. */
2329 BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY));
2330 return head;
2331 }
2332 EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
2333
2334 /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
2335 void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n)
2336 {
2337 vq->last_avail_idx -= n;
2338 }
2339 EXPORT_SYMBOL_GPL(vhost_discard_vq_desc);
2340
2341 /* After we've used one of their buffers, we tell them about it. We'll then
2342 * want to notify the guest, using eventfd. */
2343 int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
2344 {
2345 struct vring_used_elem heads = {
2346 cpu_to_vhost32(vq, head),
2347 cpu_to_vhost32(vq, len)
2348 };
2349
2350 return vhost_add_used_n(vq, &heads, 1);
2351 }
2352 EXPORT_SYMBOL_GPL(vhost_add_used);
2353
2354 static int __vhost_add_used_n(struct vhost_virtqueue *vq,
2355 struct vring_used_elem *heads,
2356 unsigned count)
2357 {
2358 vring_used_elem_t __user *used;
2359 u16 old, new;
2360 int start;
2361
2362 start = vq->last_used_idx & (vq->num - 1);
2363 used = vq->used->ring + start;
2364 if (vhost_put_used(vq, heads, start, count)) {
2365 vq_err(vq, "Failed to write used");
2366 return -EFAULT;
2367 }
2368 if (unlikely(vq->log_used)) {
2369 /* Make sure data is seen before log. */
2370 smp_wmb();
2371 /* Log used ring entry write. */
2372 log_used(vq, ((void __user *)used - (void __user *)vq->used),
2373 count * sizeof *used);
2374 }
2375 old = vq->last_used_idx;
2376 new = (vq->last_used_idx += count);
2377 /* If the driver never bothers to signal in a very long while,
2378 * used index might wrap around. If that happens, invalidate
2379 * signalled_used index we stored. TODO: make sure driver
2380 * signals at least once in 2^16 and remove this. */
2381 if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old)))
2382 vq->signalled_used_valid = false;
2383 return 0;
2384 }
2385
2386 /* After we've used one of their buffers, we tell them about it. We'll then
2387 * want to notify the guest, using eventfd. */
2388 int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
2389 unsigned count)
2390 {
2391 int start, n, r;
2392
2393 start = vq->last_used_idx & (vq->num - 1);
2394 n = vq->num - start;
2395 if (n < count) {
2396 r = __vhost_add_used_n(vq, heads, n);
2397 if (r < 0)
2398 return r;
2399 heads += n;
2400 count -= n;
2401 }
2402 r = __vhost_add_used_n(vq, heads, count);
2403
2404 /* Make sure buffer is written before we update index. */
2405 smp_wmb();
2406 if (vhost_put_used_idx(vq)) {
2407 vq_err(vq, "Failed to increment used idx");
2408 return -EFAULT;
2409 }
2410 if (unlikely(vq->log_used)) {
2411 /* Make sure used idx is seen before log. */
2412 smp_wmb();
2413 /* Log used index update. */
2414 log_used(vq, offsetof(struct vring_used, idx),
2415 sizeof vq->used->idx);
2416 if (vq->log_ctx)
2417 eventfd_signal(vq->log_ctx, 1);
2418 }
2419 return r;
2420 }
2421 EXPORT_SYMBOL_GPL(vhost_add_used_n);
2422
2423 static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2424 {
2425 __u16 old, new;
2426 __virtio16 event;
2427 bool v;
2428 /* Flush out used index updates. This is paired
2429 * with the barrier that the Guest executes when enabling
2430 * interrupts. */
2431 smp_mb();
2432
2433 if (vhost_has_feature(vq, VIRTIO_F_NOTIFY_ON_EMPTY) &&
2434 unlikely(vq->avail_idx == vq->last_avail_idx))
2435 return true;
2436
2437 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2438 __virtio16 flags;
2439 if (vhost_get_avail_flags(vq, &flags)) {
2440 vq_err(vq, "Failed to get flags");
2441 return true;
2442 }
2443 return !(flags & cpu_to_vhost16(vq, VRING_AVAIL_F_NO_INTERRUPT));
2444 }
2445 old = vq->signalled_used;
2446 v = vq->signalled_used_valid;
2447 new = vq->signalled_used = vq->last_used_idx;
2448 vq->signalled_used_valid = true;
2449
2450 if (unlikely(!v))
2451 return true;
2452
2453 if (vhost_get_used_event(vq, &event)) {
2454 vq_err(vq, "Failed to get used event idx");
2455 return true;
2456 }
2457 return vring_need_event(vhost16_to_cpu(vq, event), new, old);
2458 }
2459
2460 /* This actually signals the guest, using eventfd. */
2461 void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2462 {
2463 /* Signal the Guest tell them we used something up. */
2464 if (vq->call_ctx.ctx && vhost_notify(dev, vq))
2465 eventfd_signal(vq->call_ctx.ctx, 1);
2466 }
2467 EXPORT_SYMBOL_GPL(vhost_signal);
2468
2469 /* And here's the combo meal deal. Supersize me! */
2470 void vhost_add_used_and_signal(struct vhost_dev *dev,
2471 struct vhost_virtqueue *vq,
2472 unsigned int head, int len)
2473 {
2474 vhost_add_used(vq, head, len);
2475 vhost_signal(dev, vq);
2476 }
2477 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal);
2478
2479 /* multi-buffer version of vhost_add_used_and_signal */
2480 void vhost_add_used_and_signal_n(struct vhost_dev *dev,
2481 struct vhost_virtqueue *vq,
2482 struct vring_used_elem *heads, unsigned count)
2483 {
2484 vhost_add_used_n(vq, heads, count);
2485 vhost_signal(dev, vq);
2486 }
2487 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
2488
2489 /* return true if we're sure that avaiable ring is empty */
2490 bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2491 {
2492 __virtio16 avail_idx;
2493 int r;
2494
2495 if (vq->avail_idx != vq->last_avail_idx)
2496 return false;
2497
2498 r = vhost_get_avail_idx(vq, &avail_idx);
2499 if (unlikely(r))
2500 return false;
2501 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2502
2503 return vq->avail_idx == vq->last_avail_idx;
2504 }
2505 EXPORT_SYMBOL_GPL(vhost_vq_avail_empty);
2506
2507 /* OK, now we need to know about added descriptors. */
2508 bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2509 {
2510 __virtio16 avail_idx;
2511 int r;
2512
2513 if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
2514 return false;
2515 vq->used_flags &= ~VRING_USED_F_NO_NOTIFY;
2516 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2517 r = vhost_update_used_flags(vq);
2518 if (r) {
2519 vq_err(vq, "Failed to enable notification at %p: %d\n",
2520 &vq->used->flags, r);
2521 return false;
2522 }
2523 } else {
2524 r = vhost_update_avail_event(vq, vq->avail_idx);
2525 if (r) {
2526 vq_err(vq, "Failed to update avail event index at %p: %d\n",
2527 vhost_avail_event(vq), r);
2528 return false;
2529 }
2530 }
2531 /* They could have slipped one in as we were doing that: make
2532 * sure it's written, then check again. */
2533 smp_mb();
2534 r = vhost_get_avail_idx(vq, &avail_idx);
2535 if (r) {
2536 vq_err(vq, "Failed to check avail idx at %p: %d\n",
2537 &vq->avail->idx, r);
2538 return false;
2539 }
2540
2541 return vhost16_to_cpu(vq, avail_idx) != vq->avail_idx;
2542 }
2543 EXPORT_SYMBOL_GPL(vhost_enable_notify);
2544
2545 /* We don't need to be notified again. */
2546 void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2547 {
2548 int r;
2549
2550 if (vq->used_flags & VRING_USED_F_NO_NOTIFY)
2551 return;
2552 vq->used_flags |= VRING_USED_F_NO_NOTIFY;
2553 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2554 r = vhost_update_used_flags(vq);
2555 if (r)
2556 vq_err(vq, "Failed to disable notification at %p: %d\n",
2557 &vq->used->flags, r);
2558 }
2559 }
2560 EXPORT_SYMBOL_GPL(vhost_disable_notify);
2561
2562 /* Create a new message. */
2563 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type)
2564 {
2565 struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL);
2566 if (!node)
2567 return NULL;
2568
2569 /* Make sure all padding within the structure is initialized. */
2570 memset(&node->msg, 0, sizeof node->msg);
2571 node->vq = vq;
2572 node->msg.type = type;
2573 return node;
2574 }
2575 EXPORT_SYMBOL_GPL(vhost_new_msg);
2576
2577 void vhost_enqueue_msg(struct vhost_dev *dev, struct list_head *head,
2578 struct vhost_msg_node *node)
2579 {
2580 spin_lock(&dev->iotlb_lock);
2581 list_add_tail(&node->node, head);
2582 spin_unlock(&dev->iotlb_lock);
2583
2584 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
2585 }
2586 EXPORT_SYMBOL_GPL(vhost_enqueue_msg);
2587
2588 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
2589 struct list_head *head)
2590 {
2591 struct vhost_msg_node *node = NULL;
2592
2593 spin_lock(&dev->iotlb_lock);
2594 if (!list_empty(head)) {
2595 node = list_first_entry(head, struct vhost_msg_node,
2596 node);
2597 list_del(&node->node);
2598 }
2599 spin_unlock(&dev->iotlb_lock);
2600
2601 return node;
2602 }
2603 EXPORT_SYMBOL_GPL(vhost_dequeue_msg);
2604
2605 void vhost_set_backend_features(struct vhost_dev *dev, u64 features)
2606 {
2607 struct vhost_virtqueue *vq;
2608 int i;
2609
2610 mutex_lock(&dev->mutex);
2611 for (i = 0; i < dev->nvqs; ++i) {
2612 vq = dev->vqs[i];
2613 mutex_lock(&vq->mutex);
2614 vq->acked_backend_features = features;
2615 mutex_unlock(&vq->mutex);
2616 }
2617 mutex_unlock(&dev->mutex);
2618 }
2619 EXPORT_SYMBOL_GPL(vhost_set_backend_features);
2620
2621 static int __init vhost_init(void)
2622 {
2623 return 0;
2624 }
2625
2626 static void __exit vhost_exit(void)
2627 {
2628 }
2629
2630 module_init(vhost_init);
2631 module_exit(vhost_exit);
2632
2633 MODULE_VERSION("0.0.1");
2634 MODULE_LICENSE("GPL v2");
2635 MODULE_AUTHOR("Michael S. Tsirkin");
2636 MODULE_DESCRIPTION("Host kernel accelerator for virtio");
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