1 // SPDX-License-Identifier: GPL-2.0-only
2 /* Copyright (C) 2009 Red Hat, Inc.
3 * Copyright (C) 2006 Rusty Russell IBM Corporation
5 * Author: Michael S. Tsirkin <mst@redhat.com>
7 * Inspiration, some code, and most witty comments come from
8 * Documentation/virtual/lguest/lguest.c, by Rusty Russell
10 * Generic code for virtio server in host kernel.
13 #include <linux/eventfd.h>
14 #include <linux/vhost.h>
15 #include <linux/uio.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>
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)");
46 VHOST_MEMORY_F_LOG = 0x1,
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])
52 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
53 static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
55 vq->user_be = !virtio_legacy_is_little_endian();
58 static void vhost_enable_cross_endian_big(struct vhost_virtqueue *vq)
63 static void vhost_enable_cross_endian_little(struct vhost_virtqueue *vq)
68 static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
70 struct vhost_vring_state s;
75 if (copy_from_user(&s, argp, sizeof(s)))
78 if (s.num != VHOST_VRING_LITTLE_ENDIAN &&
79 s.num != VHOST_VRING_BIG_ENDIAN)
82 if (s.num == VHOST_VRING_BIG_ENDIAN)
83 vhost_enable_cross_endian_big(vq);
85 vhost_enable_cross_endian_little(vq);
90 static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
93 struct vhost_vring_state s = {
98 if (copy_to_user(argp, &s, sizeof(s)))
104 static void vhost_init_is_le(struct vhost_virtqueue *vq)
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.
111 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1) || !vq->user_be;
114 static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
118 static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
123 static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
129 static void vhost_init_is_le(struct vhost_virtqueue *vq)
131 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1)
132 || virtio_legacy_is_little_endian();
134 #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
136 static void vhost_reset_is_le(struct vhost_virtqueue *vq)
138 vhost_init_is_le(vq);
141 struct vhost_flush_struct {
142 struct vhost_work work;
143 struct completion wait_event;
146 static void vhost_flush_work(struct vhost_work *work)
148 struct vhost_flush_struct *s;
150 s = container_of(work, struct vhost_flush_struct, work);
151 complete(&s->wait_event);
154 static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
157 struct vhost_poll *poll;
159 poll = container_of(pt, struct vhost_poll, table);
161 add_wait_queue(wqh, &poll->wait);
164 static int vhost_poll_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync,
167 struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait);
168 struct vhost_work *work = &poll->work;
170 if (!(key_to_poll(key) & poll->mask))
173 if (!poll->dev->use_worker)
176 vhost_poll_queue(poll);
181 void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn)
183 clear_bit(VHOST_WORK_QUEUED, &work->flags);
186 EXPORT_SYMBOL_GPL(vhost_work_init);
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)
192 init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup);
193 init_poll_funcptr(&poll->table, vhost_poll_func);
198 vhost_work_init(&poll->work, fn);
200 EXPORT_SYMBOL_GPL(vhost_poll_init);
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)
211 mask = vfs_poll(file, &poll->table);
213 vhost_poll_wakeup(&poll->wait, 0, 0, poll_to_key(mask));
214 if (mask & EPOLLERR) {
215 vhost_poll_stop(poll);
221 EXPORT_SYMBOL_GPL(vhost_poll_start);
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)
228 remove_wait_queue(poll->wqh, &poll->wait);
232 EXPORT_SYMBOL_GPL(vhost_poll_stop);
234 void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work)
236 struct vhost_flush_struct flush;
239 init_completion(&flush.wait_event);
240 vhost_work_init(&flush.work, vhost_flush_work);
242 vhost_work_queue(dev, &flush.work);
243 wait_for_completion(&flush.wait_event);
246 EXPORT_SYMBOL_GPL(vhost_work_flush);
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)
252 vhost_work_flush(poll->dev, &poll->work);
254 EXPORT_SYMBOL_GPL(vhost_poll_flush);
256 void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work)
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.
266 llist_add(&work->node, &dev->work_list);
267 wake_up_process(dev->worker);
270 EXPORT_SYMBOL_GPL(vhost_work_queue);
272 /* A lockless hint for busy polling code to exit the loop */
273 bool vhost_has_work(struct vhost_dev *dev)
275 return !llist_empty(&dev->work_list);
277 EXPORT_SYMBOL_GPL(vhost_has_work);
279 void vhost_poll_queue(struct vhost_poll *poll)
281 vhost_work_queue(poll->dev, &poll->work);
283 EXPORT_SYMBOL_GPL(vhost_poll_queue);
285 static void __vhost_vq_meta_reset(struct vhost_virtqueue *vq)
289 for (j = 0; j < VHOST_NUM_ADDRS; j++)
290 vq->meta_iotlb[j] = NULL;
293 static void vhost_vq_meta_reset(struct vhost_dev *d)
297 for (i = 0; i < d->nvqs; ++i)
298 __vhost_vq_meta_reset(d->vqs[i]);
301 static void vhost_vring_call_reset(struct vhost_vring_call *call_ctx)
303 call_ctx->ctx = NULL;
304 memset(&call_ctx->producer, 0x0, sizeof(struct irq_bypass_producer));
307 bool vhost_vq_is_setup(struct vhost_virtqueue *vq)
309 return vq->avail && vq->desc && vq->used && vhost_vq_access_ok(vq);
311 EXPORT_SYMBOL_GPL(vhost_vq_is_setup);
313 static void vhost_vq_reset(struct vhost_dev *dev,
314 struct vhost_virtqueue *vq)
320 vq->last_avail_idx = 0;
322 vq->last_used_idx = 0;
323 vq->signalled_used = 0;
324 vq->signalled_used_valid = false;
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;
332 vq->error_ctx = NULL;
335 vhost_disable_cross_endian(vq);
336 vhost_reset_is_le(vq);
337 vq->busyloop_timeout = 0;
340 vhost_vring_call_reset(&vq->call_ctx);
341 __vhost_vq_meta_reset(vq);
344 static int vhost_worker(void *data)
346 struct vhost_dev *dev = data;
347 struct vhost_work *work, *work_next;
348 struct llist_node *node;
350 kthread_use_mm(dev->mm);
353 /* mb paired w/ kthread_stop */
354 set_current_state(TASK_INTERRUPTIBLE);
356 if (kthread_should_stop()) {
357 __set_current_state(TASK_RUNNING);
361 node = llist_del_all(&dev->work_list);
365 node = llist_reverse_order(node);
366 /* make sure flag is seen after deletion */
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);
378 kthread_unuse_mm(dev->mm);
382 static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq)
392 /* Helper to allocate iovec buffers for all vqs. */
393 static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
395 struct vhost_virtqueue *vq;
398 for (i = 0; i < dev->nvqs; ++i) {
400 vq->indirect = kmalloc_array(UIO_MAXIOV,
401 sizeof(*vq->indirect),
403 vq->log = kmalloc_array(dev->iov_limit, sizeof(*vq->log),
405 vq->heads = kmalloc_array(dev->iov_limit, sizeof(*vq->heads),
407 if (!vq->indirect || !vq->log || !vq->heads)
414 vhost_vq_free_iovecs(dev->vqs[i]);
418 static void vhost_dev_free_iovecs(struct vhost_dev *dev)
422 for (i = 0; i < dev->nvqs; ++i)
423 vhost_vq_free_iovecs(dev->vqs[i]);
426 bool vhost_exceeds_weight(struct vhost_virtqueue *vq,
427 int pkts, int total_len)
429 struct vhost_dev *dev = vq->dev;
431 if ((dev->byte_weight && total_len >= dev->byte_weight) ||
432 pkts >= dev->weight) {
433 vhost_poll_queue(&vq->poll);
439 EXPORT_SYMBOL_GPL(vhost_exceeds_weight);
441 static size_t vhost_get_avail_size(struct vhost_virtqueue *vq,
444 size_t event __maybe_unused =
445 vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
447 return sizeof(*vq->avail) +
448 sizeof(*vq->avail->ring) * num + event;
451 static size_t vhost_get_used_size(struct vhost_virtqueue *vq,
454 size_t event __maybe_unused =
455 vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
457 return sizeof(*vq->used) +
458 sizeof(*vq->used->ring) * num + event;
461 static size_t vhost_get_desc_size(struct vhost_virtqueue *vq,
464 return sizeof(*vq->desc) * num;
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,
471 int (*msg_handler)(struct vhost_dev *dev,
472 struct vhost_iotlb_msg *msg))
474 struct vhost_virtqueue *vq;
479 mutex_init(&dev->mutex);
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);
497 for (i = 0; i < dev->nvqs; ++i) {
503 mutex_init(&vq->mutex);
504 vhost_vq_reset(dev, vq);
506 vhost_poll_init(&vq->poll, vq->handle_kick,
510 EXPORT_SYMBOL_GPL(vhost_dev_init);
512 /* Caller should have device mutex */
513 long vhost_dev_check_owner(struct vhost_dev *dev)
515 /* Are you the owner? If not, I don't think you mean to do that */
516 return dev->mm == current->mm ? 0 : -EPERM;
518 EXPORT_SYMBOL_GPL(vhost_dev_check_owner);
520 struct vhost_attach_cgroups_struct {
521 struct vhost_work work;
522 struct task_struct *owner;
526 static void vhost_attach_cgroups_work(struct vhost_work *work)
528 struct vhost_attach_cgroups_struct *s;
530 s = container_of(work, struct vhost_attach_cgroups_struct, work);
531 s->ret = cgroup_attach_task_all(s->owner, current);
534 static int vhost_attach_cgroups(struct vhost_dev *dev)
536 struct vhost_attach_cgroups_struct attach;
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);
545 /* Caller should have device mutex */
546 bool vhost_dev_has_owner(struct vhost_dev *dev)
550 EXPORT_SYMBOL_GPL(vhost_dev_has_owner);
552 static void vhost_attach_mm(struct vhost_dev *dev)
554 /* No owner, become one */
555 if (dev->use_worker) {
556 dev->mm = get_task_mm(current);
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.
564 dev->mm = current->mm;
569 static void vhost_detach_mm(struct vhost_dev *dev)
582 /* Caller should have device mutex */
583 long vhost_dev_set_owner(struct vhost_dev *dev)
585 struct task_struct *worker;
588 /* Is there an owner already? */
589 if (vhost_dev_has_owner(dev)) {
594 vhost_attach_mm(dev);
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);
605 dev->worker = worker;
606 wake_up_process(worker); /* avoid contributing to loadavg */
608 err = vhost_attach_cgroups(dev);
613 err = vhost_dev_alloc_iovecs(dev);
620 kthread_stop(dev->worker);
624 vhost_detach_mm(dev);
625 dev->kcov_handle = 0;
629 EXPORT_SYMBOL_GPL(vhost_dev_set_owner);
631 static struct vhost_iotlb *iotlb_alloc(void)
633 return vhost_iotlb_alloc(max_iotlb_entries,
634 VHOST_IOTLB_FLAG_RETIRE);
637 struct vhost_iotlb *vhost_dev_reset_owner_prepare(void)
639 return iotlb_alloc();
641 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare);
643 /* Caller should have device mutex */
644 void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_iotlb *umem)
648 vhost_dev_cleanup(dev);
651 /* We don't need VQ locks below since vhost_dev_cleanup makes sure
652 * VQs aren't running.
654 for (i = 0; i < dev->nvqs; ++i)
655 dev->vqs[i]->umem = umem;
657 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner);
659 void vhost_dev_stop(struct vhost_dev *dev)
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);
670 EXPORT_SYMBOL_GPL(vhost_dev_stop);
672 void vhost_clear_msg(struct vhost_dev *dev)
674 struct vhost_msg_node *node, *n;
676 spin_lock(&dev->iotlb_lock);
678 list_for_each_entry_safe(node, n, &dev->read_list, node) {
679 list_del(&node->node);
683 list_for_each_entry_safe(node, n, &dev->pending_list, node) {
684 list_del(&node->node);
688 spin_unlock(&dev->iotlb_lock);
690 EXPORT_SYMBOL_GPL(vhost_clear_msg);
692 void vhost_dev_cleanup(struct vhost_dev *dev)
696 for (i = 0; i < dev->nvqs; ++i) {
697 if (dev->vqs[i]->error_ctx)
698 eventfd_ctx_put(dev->vqs[i]->error_ctx);
699 if (dev->vqs[i]->kick)
700 fput(dev->vqs[i]->kick);
701 if (dev->vqs[i]->call_ctx.ctx)
702 eventfd_ctx_put(dev->vqs[i]->call_ctx.ctx);
703 vhost_vq_reset(dev, dev->vqs[i]);
705 vhost_dev_free_iovecs(dev);
707 eventfd_ctx_put(dev->log_ctx);
709 /* No one will access memory at this point */
710 vhost_iotlb_free(dev->umem);
712 vhost_iotlb_free(dev->iotlb);
714 vhost_clear_msg(dev);
715 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
716 WARN_ON(!llist_empty(&dev->work_list));
718 kthread_stop(dev->worker);
720 dev->kcov_handle = 0;
722 vhost_detach_mm(dev);
724 EXPORT_SYMBOL_GPL(vhost_dev_cleanup);
726 static bool log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
728 u64 a = addr / VHOST_PAGE_SIZE / 8;
730 /* Make sure 64 bit math will not overflow. */
731 if (a > ULONG_MAX - (unsigned long)log_base ||
732 a + (unsigned long)log_base > ULONG_MAX)
735 return access_ok(log_base + a,
736 (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8);
739 /* Make sure 64 bit math will not overflow. */
740 static bool vhost_overflow(u64 uaddr, u64 size)
742 if (uaddr > ULONG_MAX || size > ULONG_MAX)
748 return uaddr > ULONG_MAX - size + 1;
751 /* Caller should have vq mutex and device mutex. */
752 static bool vq_memory_access_ok(void __user *log_base, struct vhost_iotlb *umem,
755 struct vhost_iotlb_map *map;
760 list_for_each_entry(map, &umem->list, link) {
761 unsigned long a = map->addr;
763 if (vhost_overflow(map->addr, map->size))
767 if (!access_ok((void __user *)a, map->size))
769 else if (log_all && !log_access_ok(log_base,
777 static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq,
778 u64 addr, unsigned int size,
781 const struct vhost_iotlb_map *map = vq->meta_iotlb[type];
786 return (void __user *)(uintptr_t)(map->addr + addr - map->start);
789 /* Can we switch to this memory table? */
790 /* Caller should have device mutex but not vq mutex */
791 static bool memory_access_ok(struct vhost_dev *d, struct vhost_iotlb *umem,
796 for (i = 0; i < d->nvqs; ++i) {
800 mutex_lock(&d->vqs[i]->mutex);
801 log = log_all || vhost_has_feature(d->vqs[i], VHOST_F_LOG_ALL);
802 /* If ring is inactive, will check when it's enabled. */
803 if (d->vqs[i]->private_data)
804 ok = vq_memory_access_ok(d->vqs[i]->log_base,
808 mutex_unlock(&d->vqs[i]->mutex);
815 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
816 struct iovec iov[], int iov_size, int access);
818 static int vhost_copy_to_user(struct vhost_virtqueue *vq, void __user *to,
819 const void *from, unsigned size)
824 return __copy_to_user(to, from, size);
826 /* This function should be called after iotlb
827 * prefetch, which means we're sure that all vq
828 * could be access through iotlb. So -EAGAIN should
829 * not happen in this case.
832 void __user *uaddr = vhost_vq_meta_fetch(vq,
833 (u64)(uintptr_t)to, size,
837 return __copy_to_user(uaddr, from, size);
839 ret = translate_desc(vq, (u64)(uintptr_t)to, size, vq->iotlb_iov,
840 ARRAY_SIZE(vq->iotlb_iov),
844 iov_iter_init(&t, WRITE, vq->iotlb_iov, ret, size);
845 ret = copy_to_iter(from, size, &t);
853 static int vhost_copy_from_user(struct vhost_virtqueue *vq, void *to,
854 void __user *from, unsigned size)
859 return __copy_from_user(to, from, size);
861 /* This function should be called after iotlb
862 * prefetch, which means we're sure that vq
863 * could be access through iotlb. So -EAGAIN should
864 * not happen in this case.
866 void __user *uaddr = vhost_vq_meta_fetch(vq,
867 (u64)(uintptr_t)from, size,
872 return __copy_from_user(to, uaddr, size);
874 ret = translate_desc(vq, (u64)(uintptr_t)from, size, vq->iotlb_iov,
875 ARRAY_SIZE(vq->iotlb_iov),
878 vq_err(vq, "IOTLB translation failure: uaddr "
879 "%p size 0x%llx\n", from,
880 (unsigned long long) size);
883 iov_iter_init(&f, READ, vq->iotlb_iov, ret, size);
884 ret = copy_from_iter(to, size, &f);
893 static void __user *__vhost_get_user_slow(struct vhost_virtqueue *vq,
894 void __user *addr, unsigned int size,
899 ret = translate_desc(vq, (u64)(uintptr_t)addr, size, vq->iotlb_iov,
900 ARRAY_SIZE(vq->iotlb_iov),
903 vq_err(vq, "IOTLB translation failure: uaddr "
904 "%p size 0x%llx\n", addr,
905 (unsigned long long) size);
909 if (ret != 1 || vq->iotlb_iov[0].iov_len != size) {
910 vq_err(vq, "Non atomic userspace memory access: uaddr "
911 "%p size 0x%llx\n", addr,
912 (unsigned long long) size);
916 return vq->iotlb_iov[0].iov_base;
919 /* This function should be called after iotlb
920 * prefetch, which means we're sure that vq
921 * could be access through iotlb. So -EAGAIN should
922 * not happen in this case.
924 static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq,
925 void __user *addr, unsigned int size,
928 void __user *uaddr = vhost_vq_meta_fetch(vq,
929 (u64)(uintptr_t)addr, size, type);
933 return __vhost_get_user_slow(vq, addr, size, type);
936 #define vhost_put_user(vq, x, ptr) \
940 ret = __put_user(x, ptr); \
942 __typeof__(ptr) to = \
943 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
944 sizeof(*ptr), VHOST_ADDR_USED); \
946 ret = __put_user(x, to); \
953 static inline int vhost_put_avail_event(struct vhost_virtqueue *vq)
955 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx),
956 vhost_avail_event(vq));
959 static inline int vhost_put_used(struct vhost_virtqueue *vq,
960 struct vring_used_elem *head, int idx,
963 return vhost_copy_to_user(vq, vq->used->ring + idx, head,
964 count * sizeof(*head));
967 static inline int vhost_put_used_flags(struct vhost_virtqueue *vq)
970 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags),
974 static inline int vhost_put_used_idx(struct vhost_virtqueue *vq)
977 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx),
981 #define vhost_get_user(vq, x, ptr, type) \
985 ret = __get_user(x, ptr); \
987 __typeof__(ptr) from = \
988 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
992 ret = __get_user(x, from); \
999 #define vhost_get_avail(vq, x, ptr) \
1000 vhost_get_user(vq, x, ptr, VHOST_ADDR_AVAIL)
1002 #define vhost_get_used(vq, x, ptr) \
1003 vhost_get_user(vq, x, ptr, VHOST_ADDR_USED)
1005 static void vhost_dev_lock_vqs(struct vhost_dev *d)
1008 for (i = 0; i < d->nvqs; ++i)
1009 mutex_lock_nested(&d->vqs[i]->mutex, i);
1012 static void vhost_dev_unlock_vqs(struct vhost_dev *d)
1015 for (i = 0; i < d->nvqs; ++i)
1016 mutex_unlock(&d->vqs[i]->mutex);
1019 static inline int vhost_get_avail_idx(struct vhost_virtqueue *vq,
1022 return vhost_get_avail(vq, *idx, &vq->avail->idx);
1025 static inline int vhost_get_avail_head(struct vhost_virtqueue *vq,
1026 __virtio16 *head, int idx)
1028 return vhost_get_avail(vq, *head,
1029 &vq->avail->ring[idx & (vq->num - 1)]);
1032 static inline int vhost_get_avail_flags(struct vhost_virtqueue *vq,
1035 return vhost_get_avail(vq, *flags, &vq->avail->flags);
1038 static inline int vhost_get_used_event(struct vhost_virtqueue *vq,
1041 return vhost_get_avail(vq, *event, vhost_used_event(vq));
1044 static inline int vhost_get_used_idx(struct vhost_virtqueue *vq,
1047 return vhost_get_used(vq, *idx, &vq->used->idx);
1050 static inline int vhost_get_desc(struct vhost_virtqueue *vq,
1051 struct vring_desc *desc, int idx)
1053 return vhost_copy_from_user(vq, desc, vq->desc + idx, sizeof(*desc));
1056 static void vhost_iotlb_notify_vq(struct vhost_dev *d,
1057 struct vhost_iotlb_msg *msg)
1059 struct vhost_msg_node *node, *n;
1061 spin_lock(&d->iotlb_lock);
1063 list_for_each_entry_safe(node, n, &d->pending_list, node) {
1064 struct vhost_iotlb_msg *vq_msg = &node->msg.iotlb;
1065 if (msg->iova <= vq_msg->iova &&
1066 msg->iova + msg->size - 1 >= vq_msg->iova &&
1067 vq_msg->type == VHOST_IOTLB_MISS) {
1068 vhost_poll_queue(&node->vq->poll);
1069 list_del(&node->node);
1074 spin_unlock(&d->iotlb_lock);
1077 static bool umem_access_ok(u64 uaddr, u64 size, int access)
1079 unsigned long a = uaddr;
1081 /* Make sure 64 bit math will not overflow. */
1082 if (vhost_overflow(uaddr, size))
1085 if ((access & VHOST_ACCESS_RO) &&
1086 !access_ok((void __user *)a, size))
1088 if ((access & VHOST_ACCESS_WO) &&
1089 !access_ok((void __user *)a, size))
1094 static int vhost_process_iotlb_msg(struct vhost_dev *dev,
1095 struct vhost_iotlb_msg *msg)
1099 mutex_lock(&dev->mutex);
1100 vhost_dev_lock_vqs(dev);
1101 switch (msg->type) {
1102 case VHOST_IOTLB_UPDATE:
1107 if (!umem_access_ok(msg->uaddr, msg->size, msg->perm)) {
1111 vhost_vq_meta_reset(dev);
1112 if (vhost_iotlb_add_range(dev->iotlb, msg->iova,
1113 msg->iova + msg->size - 1,
1114 msg->uaddr, msg->perm)) {
1118 vhost_iotlb_notify_vq(dev, msg);
1120 case VHOST_IOTLB_INVALIDATE:
1125 vhost_vq_meta_reset(dev);
1126 vhost_iotlb_del_range(dev->iotlb, msg->iova,
1127 msg->iova + msg->size - 1);
1134 vhost_dev_unlock_vqs(dev);
1135 mutex_unlock(&dev->mutex);
1139 ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
1140 struct iov_iter *from)
1142 struct vhost_iotlb_msg msg;
1146 ret = copy_from_iter(&type, sizeof(type), from);
1147 if (ret != sizeof(type)) {
1153 case VHOST_IOTLB_MSG:
1154 /* There maybe a hole after type for V1 message type,
1157 offset = offsetof(struct vhost_msg, iotlb) - sizeof(int);
1159 case VHOST_IOTLB_MSG_V2:
1160 offset = sizeof(__u32);
1167 iov_iter_advance(from, offset);
1168 ret = copy_from_iter(&msg, sizeof(msg), from);
1169 if (ret != sizeof(msg)) {
1174 if (dev->msg_handler)
1175 ret = dev->msg_handler(dev, &msg);
1177 ret = vhost_process_iotlb_msg(dev, &msg);
1183 ret = (type == VHOST_IOTLB_MSG) ? sizeof(struct vhost_msg) :
1184 sizeof(struct vhost_msg_v2);
1188 EXPORT_SYMBOL(vhost_chr_write_iter);
1190 __poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
1195 poll_wait(file, &dev->wait, wait);
1197 if (!list_empty(&dev->read_list))
1198 mask |= EPOLLIN | EPOLLRDNORM;
1202 EXPORT_SYMBOL(vhost_chr_poll);
1204 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
1208 struct vhost_msg_node *node;
1210 unsigned size = sizeof(struct vhost_msg);
1212 if (iov_iter_count(to) < size)
1217 prepare_to_wait(&dev->wait, &wait,
1218 TASK_INTERRUPTIBLE);
1220 node = vhost_dequeue_msg(dev, &dev->read_list);
1227 if (signal_pending(current)) {
1240 finish_wait(&dev->wait, &wait);
1243 struct vhost_iotlb_msg *msg;
1244 void *start = &node->msg;
1246 switch (node->msg.type) {
1247 case VHOST_IOTLB_MSG:
1248 size = sizeof(node->msg);
1249 msg = &node->msg.iotlb;
1251 case VHOST_IOTLB_MSG_V2:
1252 size = sizeof(node->msg_v2);
1253 msg = &node->msg_v2.iotlb;
1260 ret = copy_to_iter(start, size, to);
1261 if (ret != size || msg->type != VHOST_IOTLB_MISS) {
1265 vhost_enqueue_msg(dev, &dev->pending_list, node);
1270 EXPORT_SYMBOL_GPL(vhost_chr_read_iter);
1272 static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access)
1274 struct vhost_dev *dev = vq->dev;
1275 struct vhost_msg_node *node;
1276 struct vhost_iotlb_msg *msg;
1277 bool v2 = vhost_backend_has_feature(vq, VHOST_BACKEND_F_IOTLB_MSG_V2);
1279 node = vhost_new_msg(vq, v2 ? VHOST_IOTLB_MSG_V2 : VHOST_IOTLB_MSG);
1284 node->msg_v2.type = VHOST_IOTLB_MSG_V2;
1285 msg = &node->msg_v2.iotlb;
1287 msg = &node->msg.iotlb;
1290 msg->type = VHOST_IOTLB_MISS;
1294 vhost_enqueue_msg(dev, &dev->read_list, node);
1299 static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
1300 vring_desc_t __user *desc,
1301 vring_avail_t __user *avail,
1302 vring_used_t __user *used)
1305 /* If an IOTLB device is present, the vring addresses are
1306 * GIOVAs. Access validation occurs at prefetch time. */
1310 return access_ok(desc, vhost_get_desc_size(vq, num)) &&
1311 access_ok(avail, vhost_get_avail_size(vq, num)) &&
1312 access_ok(used, vhost_get_used_size(vq, num));
1315 static void vhost_vq_meta_update(struct vhost_virtqueue *vq,
1316 const struct vhost_iotlb_map *map,
1319 int access = (type == VHOST_ADDR_USED) ?
1320 VHOST_ACCESS_WO : VHOST_ACCESS_RO;
1322 if (likely(map->perm & access))
1323 vq->meta_iotlb[type] = map;
1326 static bool iotlb_access_ok(struct vhost_virtqueue *vq,
1327 int access, u64 addr, u64 len, int type)
1329 const struct vhost_iotlb_map *map;
1330 struct vhost_iotlb *umem = vq->iotlb;
1331 u64 s = 0, size, orig_addr = addr, last = addr + len - 1;
1333 if (vhost_vq_meta_fetch(vq, addr, len, type))
1337 map = vhost_iotlb_itree_first(umem, addr, last);
1338 if (map == NULL || map->start > addr) {
1339 vhost_iotlb_miss(vq, addr, access);
1341 } else if (!(map->perm & access)) {
1342 /* Report the possible access violation by
1343 * request another translation from userspace.
1348 size = map->size - addr + map->start;
1350 if (orig_addr == addr && size >= len)
1351 vhost_vq_meta_update(vq, map, type);
1360 int vq_meta_prefetch(struct vhost_virtqueue *vq)
1362 unsigned int num = vq->num;
1367 return iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->desc,
1368 vhost_get_desc_size(vq, num), VHOST_ADDR_DESC) &&
1369 iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->avail,
1370 vhost_get_avail_size(vq, num),
1371 VHOST_ADDR_AVAIL) &&
1372 iotlb_access_ok(vq, VHOST_MAP_WO, (u64)(uintptr_t)vq->used,
1373 vhost_get_used_size(vq, num), VHOST_ADDR_USED);
1375 EXPORT_SYMBOL_GPL(vq_meta_prefetch);
1377 /* Can we log writes? */
1378 /* Caller should have device mutex but not vq mutex */
1379 bool vhost_log_access_ok(struct vhost_dev *dev)
1381 return memory_access_ok(dev, dev->umem, 1);
1383 EXPORT_SYMBOL_GPL(vhost_log_access_ok);
1385 static bool vq_log_used_access_ok(struct vhost_virtqueue *vq,
1386 void __user *log_base,
1390 /* If an IOTLB device is present, log_addr is a GIOVA that
1391 * will never be logged by log_used(). */
1395 return !log_used || log_access_ok(log_base, log_addr,
1396 vhost_get_used_size(vq, vq->num));
1399 /* Verify access for write logging. */
1400 /* Caller should have vq mutex and device mutex */
1401 static bool vq_log_access_ok(struct vhost_virtqueue *vq,
1402 void __user *log_base)
1404 return vq_memory_access_ok(log_base, vq->umem,
1405 vhost_has_feature(vq, VHOST_F_LOG_ALL)) &&
1406 vq_log_used_access_ok(vq, log_base, vq->log_used, vq->log_addr);
1409 /* Can we start vq? */
1410 /* Caller should have vq mutex and device mutex */
1411 bool vhost_vq_access_ok(struct vhost_virtqueue *vq)
1413 if (!vq_log_access_ok(vq, vq->log_base))
1416 return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used);
1418 EXPORT_SYMBOL_GPL(vhost_vq_access_ok);
1420 static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
1422 struct vhost_memory mem, *newmem;
1423 struct vhost_memory_region *region;
1424 struct vhost_iotlb *newumem, *oldumem;
1425 unsigned long size = offsetof(struct vhost_memory, regions);
1428 if (copy_from_user(&mem, m, size))
1432 if (mem.nregions > max_mem_regions)
1434 newmem = kvzalloc(struct_size(newmem, regions, mem.nregions),
1439 memcpy(newmem, &mem, size);
1440 if (copy_from_user(newmem->regions, m->regions,
1441 flex_array_size(newmem, regions, mem.nregions))) {
1446 newumem = iotlb_alloc();
1452 for (region = newmem->regions;
1453 region < newmem->regions + mem.nregions;
1455 if (vhost_iotlb_add_range(newumem,
1456 region->guest_phys_addr,
1457 region->guest_phys_addr +
1458 region->memory_size - 1,
1459 region->userspace_addr,
1464 if (!memory_access_ok(d, newumem, 0))
1470 /* All memory accesses are done under some VQ mutex. */
1471 for (i = 0; i < d->nvqs; ++i) {
1472 mutex_lock(&d->vqs[i]->mutex);
1473 d->vqs[i]->umem = newumem;
1474 mutex_unlock(&d->vqs[i]->mutex);
1478 vhost_iotlb_free(oldumem);
1482 vhost_iotlb_free(newumem);
1487 static long vhost_vring_set_num(struct vhost_dev *d,
1488 struct vhost_virtqueue *vq,
1491 struct vhost_vring_state s;
1493 /* Resizing ring with an active backend?
1494 * You don't want to do that. */
1495 if (vq->private_data)
1498 if (copy_from_user(&s, argp, sizeof s))
1501 if (!s.num || s.num > 0xffff || (s.num & (s.num - 1)))
1508 static long vhost_vring_set_addr(struct vhost_dev *d,
1509 struct vhost_virtqueue *vq,
1512 struct vhost_vring_addr a;
1514 if (copy_from_user(&a, argp, sizeof a))
1516 if (a.flags & ~(0x1 << VHOST_VRING_F_LOG))
1519 /* For 32bit, verify that the top 32bits of the user
1520 data are set to zero. */
1521 if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr ||
1522 (u64)(unsigned long)a.used_user_addr != a.used_user_addr ||
1523 (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr)
1526 /* Make sure it's safe to cast pointers to vring types. */
1527 BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE);
1528 BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE);
1529 if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) ||
1530 (a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) ||
1531 (a.log_guest_addr & (VRING_USED_ALIGN_SIZE - 1)))
1534 /* We only verify access here if backend is configured.
1535 * If it is not, we don't as size might not have been setup.
1536 * We will verify when backend is configured. */
1537 if (vq->private_data) {
1538 if (!vq_access_ok(vq, vq->num,
1539 (void __user *)(unsigned long)a.desc_user_addr,
1540 (void __user *)(unsigned long)a.avail_user_addr,
1541 (void __user *)(unsigned long)a.used_user_addr))
1544 /* Also validate log access for used ring if enabled. */
1545 if (!vq_log_used_access_ok(vq, vq->log_base,
1546 a.flags & (0x1 << VHOST_VRING_F_LOG),
1551 vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG));
1552 vq->desc = (void __user *)(unsigned long)a.desc_user_addr;
1553 vq->avail = (void __user *)(unsigned long)a.avail_user_addr;
1554 vq->log_addr = a.log_guest_addr;
1555 vq->used = (void __user *)(unsigned long)a.used_user_addr;
1560 static long vhost_vring_set_num_addr(struct vhost_dev *d,
1561 struct vhost_virtqueue *vq,
1567 mutex_lock(&vq->mutex);
1570 case VHOST_SET_VRING_NUM:
1571 r = vhost_vring_set_num(d, vq, argp);
1573 case VHOST_SET_VRING_ADDR:
1574 r = vhost_vring_set_addr(d, vq, argp);
1580 mutex_unlock(&vq->mutex);
1584 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
1586 struct file *eventfp, *filep = NULL;
1587 bool pollstart = false, pollstop = false;
1588 struct eventfd_ctx *ctx = NULL;
1589 u32 __user *idxp = argp;
1590 struct vhost_virtqueue *vq;
1591 struct vhost_vring_state s;
1592 struct vhost_vring_file f;
1596 r = get_user(idx, idxp);
1602 idx = array_index_nospec(idx, d->nvqs);
1605 if (ioctl == VHOST_SET_VRING_NUM ||
1606 ioctl == VHOST_SET_VRING_ADDR) {
1607 return vhost_vring_set_num_addr(d, vq, ioctl, argp);
1610 mutex_lock(&vq->mutex);
1613 case VHOST_SET_VRING_BASE:
1614 /* Moving base with an active backend?
1615 * You don't want to do that. */
1616 if (vq->private_data) {
1620 if (copy_from_user(&s, argp, sizeof s)) {
1624 if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) {
1625 vq->last_avail_idx = s.num & 0xffff;
1626 vq->last_used_idx = (s.num >> 16) & 0xffff;
1628 if (s.num > 0xffff) {
1632 vq->last_avail_idx = s.num;
1634 /* Forget the cached index value. */
1635 vq->avail_idx = vq->last_avail_idx;
1637 case VHOST_GET_VRING_BASE:
1639 if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
1640 s.num = (u32)vq->last_avail_idx | ((u32)vq->last_used_idx << 16);
1642 s.num = vq->last_avail_idx;
1643 if (copy_to_user(argp, &s, sizeof s))
1646 case VHOST_SET_VRING_KICK:
1647 if (copy_from_user(&f, argp, sizeof f)) {
1651 eventfp = f.fd == VHOST_FILE_UNBIND ? NULL : eventfd_fget(f.fd);
1652 if (IS_ERR(eventfp)) {
1653 r = PTR_ERR(eventfp);
1656 if (eventfp != vq->kick) {
1657 pollstop = (filep = vq->kick) != NULL;
1658 pollstart = (vq->kick = eventfp) != NULL;
1662 case VHOST_SET_VRING_CALL:
1663 if (copy_from_user(&f, argp, sizeof f)) {
1667 ctx = f.fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(f.fd);
1673 swap(ctx, vq->call_ctx.ctx);
1675 case VHOST_SET_VRING_ERR:
1676 if (copy_from_user(&f, argp, sizeof f)) {
1680 ctx = f.fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(f.fd);
1685 swap(ctx, vq->error_ctx);
1687 case VHOST_SET_VRING_ENDIAN:
1688 r = vhost_set_vring_endian(vq, argp);
1690 case VHOST_GET_VRING_ENDIAN:
1691 r = vhost_get_vring_endian(vq, idx, argp);
1693 case VHOST_SET_VRING_BUSYLOOP_TIMEOUT:
1694 if (copy_from_user(&s, argp, sizeof(s))) {
1698 vq->busyloop_timeout = s.num;
1700 case VHOST_GET_VRING_BUSYLOOP_TIMEOUT:
1702 s.num = vq->busyloop_timeout;
1703 if (copy_to_user(argp, &s, sizeof(s)))
1710 if (pollstop && vq->handle_kick)
1711 vhost_poll_stop(&vq->poll);
1713 if (!IS_ERR_OR_NULL(ctx))
1714 eventfd_ctx_put(ctx);
1718 if (pollstart && vq->handle_kick)
1719 r = vhost_poll_start(&vq->poll, vq->kick);
1721 mutex_unlock(&vq->mutex);
1723 if (pollstop && vq->handle_kick)
1724 vhost_poll_flush(&vq->poll);
1727 EXPORT_SYMBOL_GPL(vhost_vring_ioctl);
1729 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled)
1731 struct vhost_iotlb *niotlb, *oiotlb;
1734 niotlb = iotlb_alloc();
1741 for (i = 0; i < d->nvqs; ++i) {
1742 struct vhost_virtqueue *vq = d->vqs[i];
1744 mutex_lock(&vq->mutex);
1746 __vhost_vq_meta_reset(vq);
1747 mutex_unlock(&vq->mutex);
1750 vhost_iotlb_free(oiotlb);
1754 EXPORT_SYMBOL_GPL(vhost_init_device_iotlb);
1756 /* Caller must have device mutex */
1757 long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
1759 struct eventfd_ctx *ctx;
1764 /* If you are not the owner, you can become one */
1765 if (ioctl == VHOST_SET_OWNER) {
1766 r = vhost_dev_set_owner(d);
1770 /* You must be the owner to do anything else */
1771 r = vhost_dev_check_owner(d);
1776 case VHOST_SET_MEM_TABLE:
1777 r = vhost_set_memory(d, argp);
1779 case VHOST_SET_LOG_BASE:
1780 if (copy_from_user(&p, argp, sizeof p)) {
1784 if ((u64)(unsigned long)p != p) {
1788 for (i = 0; i < d->nvqs; ++i) {
1789 struct vhost_virtqueue *vq;
1790 void __user *base = (void __user *)(unsigned long)p;
1792 mutex_lock(&vq->mutex);
1793 /* If ring is inactive, will check when it's enabled. */
1794 if (vq->private_data && !vq_log_access_ok(vq, base))
1797 vq->log_base = base;
1798 mutex_unlock(&vq->mutex);
1801 case VHOST_SET_LOG_FD:
1802 r = get_user(fd, (int __user *)argp);
1805 ctx = fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(fd);
1810 swap(ctx, d->log_ctx);
1811 for (i = 0; i < d->nvqs; ++i) {
1812 mutex_lock(&d->vqs[i]->mutex);
1813 d->vqs[i]->log_ctx = d->log_ctx;
1814 mutex_unlock(&d->vqs[i]->mutex);
1817 eventfd_ctx_put(ctx);
1826 EXPORT_SYMBOL_GPL(vhost_dev_ioctl);
1828 /* TODO: This is really inefficient. We need something like get_user()
1829 * (instruction directly accesses the data, with an exception table entry
1830 * returning -EFAULT). See Documentation/x86/exception-tables.rst.
1832 static int set_bit_to_user(int nr, void __user *addr)
1834 unsigned long log = (unsigned long)addr;
1837 int bit = nr + (log % PAGE_SIZE) * 8;
1840 r = pin_user_pages_fast(log, 1, FOLL_WRITE, &page);
1844 base = kmap_atomic(page);
1846 kunmap_atomic(base);
1847 unpin_user_pages_dirty_lock(&page, 1, true);
1851 static int log_write(void __user *log_base,
1852 u64 write_address, u64 write_length)
1854 u64 write_page = write_address / VHOST_PAGE_SIZE;
1859 write_length += write_address % VHOST_PAGE_SIZE;
1861 u64 base = (u64)(unsigned long)log_base;
1862 u64 log = base + write_page / 8;
1863 int bit = write_page % 8;
1864 if ((u64)(unsigned long)log != log)
1866 r = set_bit_to_user(bit, (void __user *)(unsigned long)log);
1869 if (write_length <= VHOST_PAGE_SIZE)
1871 write_length -= VHOST_PAGE_SIZE;
1877 static int log_write_hva(struct vhost_virtqueue *vq, u64 hva, u64 len)
1879 struct vhost_iotlb *umem = vq->umem;
1880 struct vhost_iotlb_map *u;
1881 u64 start, end, l, min;
1887 /* More than one GPAs can be mapped into a single HVA. So
1888 * iterate all possible umems here to be safe.
1890 list_for_each_entry(u, &umem->list, link) {
1891 if (u->addr > hva - 1 + len ||
1892 u->addr - 1 + u->size < hva)
1894 start = max(u->addr, hva);
1895 end = min(u->addr - 1 + u->size, hva - 1 + len);
1896 l = end - start + 1;
1897 r = log_write(vq->log_base,
1898 u->start + start - u->addr,
1916 static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len)
1918 struct iovec *iov = vq->log_iov;
1922 return log_write(vq->log_base, vq->log_addr + used_offset, len);
1924 ret = translate_desc(vq, (uintptr_t)vq->used + used_offset,
1925 len, iov, 64, VHOST_ACCESS_WO);
1929 for (i = 0; i < ret; i++) {
1930 ret = log_write_hva(vq, (uintptr_t)iov[i].iov_base,
1939 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
1940 unsigned int log_num, u64 len, struct iovec *iov, int count)
1944 /* Make sure data written is seen before log. */
1948 for (i = 0; i < count; i++) {
1949 r = log_write_hva(vq, (uintptr_t)iov[i].iov_base,
1957 for (i = 0; i < log_num; ++i) {
1958 u64 l = min(log[i].len, len);
1959 r = log_write(vq->log_base, log[i].addr, l);
1965 eventfd_signal(vq->log_ctx, 1);
1969 /* Length written exceeds what we have stored. This is a bug. */
1973 EXPORT_SYMBOL_GPL(vhost_log_write);
1975 static int vhost_update_used_flags(struct vhost_virtqueue *vq)
1978 if (vhost_put_used_flags(vq))
1980 if (unlikely(vq->log_used)) {
1981 /* Make sure the flag is seen before log. */
1983 /* Log used flag write. */
1984 used = &vq->used->flags;
1985 log_used(vq, (used - (void __user *)vq->used),
1986 sizeof vq->used->flags);
1988 eventfd_signal(vq->log_ctx, 1);
1993 static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
1995 if (vhost_put_avail_event(vq))
1997 if (unlikely(vq->log_used)) {
1999 /* Make sure the event is seen before log. */
2001 /* Log avail event write */
2002 used = vhost_avail_event(vq);
2003 log_used(vq, (used - (void __user *)vq->used),
2004 sizeof *vhost_avail_event(vq));
2006 eventfd_signal(vq->log_ctx, 1);
2011 int vhost_vq_init_access(struct vhost_virtqueue *vq)
2013 __virtio16 last_used_idx;
2015 bool is_le = vq->is_le;
2017 if (!vq->private_data)
2020 vhost_init_is_le(vq);
2022 r = vhost_update_used_flags(vq);
2025 vq->signalled_used_valid = false;
2027 !access_ok(&vq->used->idx, sizeof vq->used->idx)) {
2031 r = vhost_get_used_idx(vq, &last_used_idx);
2033 vq_err(vq, "Can't access used idx at %p\n",
2037 vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx);
2044 EXPORT_SYMBOL_GPL(vhost_vq_init_access);
2046 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
2047 struct iovec iov[], int iov_size, int access)
2049 const struct vhost_iotlb_map *map;
2050 struct vhost_dev *dev = vq->dev;
2051 struct vhost_iotlb *umem = dev->iotlb ? dev->iotlb : dev->umem;
2053 u64 s = 0, last = addr + len - 1;
2056 while ((u64)len > s) {
2058 if (unlikely(ret >= iov_size)) {
2063 map = vhost_iotlb_itree_first(umem, addr, last);
2064 if (map == NULL || map->start > addr) {
2065 if (umem != dev->iotlb) {
2071 } else if (!(map->perm & access)) {
2077 size = map->size - addr + map->start;
2078 _iov->iov_len = min((u64)len - s, size);
2079 _iov->iov_base = (void __user *)(unsigned long)
2080 (map->addr + addr - map->start);
2087 vhost_iotlb_miss(vq, addr, access);
2091 /* Each buffer in the virtqueues is actually a chain of descriptors. This
2092 * function returns the next descriptor in the chain,
2093 * or -1U if we're at the end. */
2094 static unsigned next_desc(struct vhost_virtqueue *vq, struct vring_desc *desc)
2098 /* If this descriptor says it doesn't chain, we're done. */
2099 if (!(desc->flags & cpu_to_vhost16(vq, VRING_DESC_F_NEXT)))
2102 /* Check they're not leading us off end of descriptors. */
2103 next = vhost16_to_cpu(vq, READ_ONCE(desc->next));
2107 static int get_indirect(struct vhost_virtqueue *vq,
2108 struct iovec iov[], unsigned int iov_size,
2109 unsigned int *out_num, unsigned int *in_num,
2110 struct vhost_log *log, unsigned int *log_num,
2111 struct vring_desc *indirect)
2113 struct vring_desc desc;
2114 unsigned int i = 0, count, found = 0;
2115 u32 len = vhost32_to_cpu(vq, indirect->len);
2116 struct iov_iter from;
2120 if (unlikely(len % sizeof desc)) {
2121 vq_err(vq, "Invalid length in indirect descriptor: "
2122 "len 0x%llx not multiple of 0x%zx\n",
2123 (unsigned long long)len,
2128 ret = translate_desc(vq, vhost64_to_cpu(vq, indirect->addr), len, vq->indirect,
2129 UIO_MAXIOV, VHOST_ACCESS_RO);
2130 if (unlikely(ret < 0)) {
2132 vq_err(vq, "Translation failure %d in indirect.\n", ret);
2135 iov_iter_init(&from, READ, vq->indirect, ret, len);
2136 count = len / sizeof desc;
2137 /* Buffers are chained via a 16 bit next field, so
2138 * we can have at most 2^16 of these. */
2139 if (unlikely(count > USHRT_MAX + 1)) {
2140 vq_err(vq, "Indirect buffer length too big: %d\n",
2146 unsigned iov_count = *in_num + *out_num;
2147 if (unlikely(++found > count)) {
2148 vq_err(vq, "Loop detected: last one at %u "
2149 "indirect size %u\n",
2153 if (unlikely(!copy_from_iter_full(&desc, sizeof(desc), &from))) {
2154 vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
2155 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
2158 if (unlikely(desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT))) {
2159 vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n",
2160 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
2164 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
2165 access = VHOST_ACCESS_WO;
2167 access = VHOST_ACCESS_RO;
2169 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
2170 vhost32_to_cpu(vq, desc.len), iov + iov_count,
2171 iov_size - iov_count, access);
2172 if (unlikely(ret < 0)) {
2174 vq_err(vq, "Translation failure %d indirect idx %d\n",
2178 /* If this is an input descriptor, increment that count. */
2179 if (access == VHOST_ACCESS_WO) {
2181 if (unlikely(log && ret)) {
2182 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
2183 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
2187 /* If it's an output descriptor, they're all supposed
2188 * to come before any input descriptors. */
2189 if (unlikely(*in_num)) {
2190 vq_err(vq, "Indirect descriptor "
2191 "has out after in: idx %d\n", i);
2196 } while ((i = next_desc(vq, &desc)) != -1);
2200 /* This looks in the virtqueue and for the first available buffer, and converts
2201 * it to an iovec for convenient access. Since descriptors consist of some
2202 * number of output then some number of input descriptors, it's actually two
2203 * iovecs, but we pack them into one and note how many of each there were.
2205 * This function returns the descriptor number found, or vq->num (which is
2206 * never a valid descriptor number) if none was found. A negative code is
2207 * returned on error. */
2208 int vhost_get_vq_desc(struct vhost_virtqueue *vq,
2209 struct iovec iov[], unsigned int iov_size,
2210 unsigned int *out_num, unsigned int *in_num,
2211 struct vhost_log *log, unsigned int *log_num)
2213 struct vring_desc desc;
2214 unsigned int i, head, found = 0;
2216 __virtio16 avail_idx;
2217 __virtio16 ring_head;
2220 /* Check it isn't doing very strange things with descriptor numbers. */
2221 last_avail_idx = vq->last_avail_idx;
2223 if (vq->avail_idx == vq->last_avail_idx) {
2224 if (unlikely(vhost_get_avail_idx(vq, &avail_idx))) {
2225 vq_err(vq, "Failed to access avail idx at %p\n",
2229 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2231 if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) {
2232 vq_err(vq, "Guest moved used index from %u to %u",
2233 last_avail_idx, vq->avail_idx);
2237 /* If there's nothing new since last we looked, return
2240 if (vq->avail_idx == last_avail_idx)
2243 /* Only get avail ring entries after they have been
2249 /* Grab the next descriptor number they're advertising, and increment
2250 * the index we've seen. */
2251 if (unlikely(vhost_get_avail_head(vq, &ring_head, last_avail_idx))) {
2252 vq_err(vq, "Failed to read head: idx %d address %p\n",
2254 &vq->avail->ring[last_avail_idx % vq->num]);
2258 head = vhost16_to_cpu(vq, ring_head);
2260 /* If their number is silly, that's an error. */
2261 if (unlikely(head >= vq->num)) {
2262 vq_err(vq, "Guest says index %u > %u is available",
2267 /* When we start there are none of either input nor output. */
2268 *out_num = *in_num = 0;
2274 unsigned iov_count = *in_num + *out_num;
2275 if (unlikely(i >= vq->num)) {
2276 vq_err(vq, "Desc index is %u > %u, head = %u",
2280 if (unlikely(++found > vq->num)) {
2281 vq_err(vq, "Loop detected: last one at %u "
2282 "vq size %u head %u\n",
2286 ret = vhost_get_desc(vq, &desc, i);
2287 if (unlikely(ret)) {
2288 vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
2292 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT)) {
2293 ret = get_indirect(vq, iov, iov_size,
2295 log, log_num, &desc);
2296 if (unlikely(ret < 0)) {
2298 vq_err(vq, "Failure detected "
2299 "in indirect descriptor at idx %d\n", i);
2305 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
2306 access = VHOST_ACCESS_WO;
2308 access = VHOST_ACCESS_RO;
2309 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
2310 vhost32_to_cpu(vq, desc.len), iov + iov_count,
2311 iov_size - iov_count, access);
2312 if (unlikely(ret < 0)) {
2314 vq_err(vq, "Translation failure %d descriptor idx %d\n",
2318 if (access == VHOST_ACCESS_WO) {
2319 /* If this is an input descriptor,
2320 * increment that count. */
2322 if (unlikely(log && ret)) {
2323 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
2324 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
2328 /* If it's an output descriptor, they're all supposed
2329 * to come before any input descriptors. */
2330 if (unlikely(*in_num)) {
2331 vq_err(vq, "Descriptor has out after in: "
2337 } while ((i = next_desc(vq, &desc)) != -1);
2339 /* On success, increment avail index. */
2340 vq->last_avail_idx++;
2342 /* Assume notifications from guest are disabled at this point,
2343 * if they aren't we would need to update avail_event index. */
2344 BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY));
2347 EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
2349 /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
2350 void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n)
2352 vq->last_avail_idx -= n;
2354 EXPORT_SYMBOL_GPL(vhost_discard_vq_desc);
2356 /* After we've used one of their buffers, we tell them about it. We'll then
2357 * want to notify the guest, using eventfd. */
2358 int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
2360 struct vring_used_elem heads = {
2361 cpu_to_vhost32(vq, head),
2362 cpu_to_vhost32(vq, len)
2365 return vhost_add_used_n(vq, &heads, 1);
2367 EXPORT_SYMBOL_GPL(vhost_add_used);
2369 static int __vhost_add_used_n(struct vhost_virtqueue *vq,
2370 struct vring_used_elem *heads,
2373 vring_used_elem_t __user *used;
2377 start = vq->last_used_idx & (vq->num - 1);
2378 used = vq->used->ring + start;
2379 if (vhost_put_used(vq, heads, start, count)) {
2380 vq_err(vq, "Failed to write used");
2383 if (unlikely(vq->log_used)) {
2384 /* Make sure data is seen before log. */
2386 /* Log used ring entry write. */
2387 log_used(vq, ((void __user *)used - (void __user *)vq->used),
2388 count * sizeof *used);
2390 old = vq->last_used_idx;
2391 new = (vq->last_used_idx += count);
2392 /* If the driver never bothers to signal in a very long while,
2393 * used index might wrap around. If that happens, invalidate
2394 * signalled_used index we stored. TODO: make sure driver
2395 * signals at least once in 2^16 and remove this. */
2396 if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old)))
2397 vq->signalled_used_valid = false;
2401 /* After we've used one of their buffers, we tell them about it. We'll then
2402 * want to notify the guest, using eventfd. */
2403 int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
2408 start = vq->last_used_idx & (vq->num - 1);
2409 n = vq->num - start;
2411 r = __vhost_add_used_n(vq, heads, n);
2417 r = __vhost_add_used_n(vq, heads, count);
2419 /* Make sure buffer is written before we update index. */
2421 if (vhost_put_used_idx(vq)) {
2422 vq_err(vq, "Failed to increment used idx");
2425 if (unlikely(vq->log_used)) {
2426 /* Make sure used idx is seen before log. */
2428 /* Log used index update. */
2429 log_used(vq, offsetof(struct vring_used, idx),
2430 sizeof vq->used->idx);
2432 eventfd_signal(vq->log_ctx, 1);
2436 EXPORT_SYMBOL_GPL(vhost_add_used_n);
2438 static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2443 /* Flush out used index updates. This is paired
2444 * with the barrier that the Guest executes when enabling
2448 if (vhost_has_feature(vq, VIRTIO_F_NOTIFY_ON_EMPTY) &&
2449 unlikely(vq->avail_idx == vq->last_avail_idx))
2452 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2454 if (vhost_get_avail_flags(vq, &flags)) {
2455 vq_err(vq, "Failed to get flags");
2458 return !(flags & cpu_to_vhost16(vq, VRING_AVAIL_F_NO_INTERRUPT));
2460 old = vq->signalled_used;
2461 v = vq->signalled_used_valid;
2462 new = vq->signalled_used = vq->last_used_idx;
2463 vq->signalled_used_valid = true;
2468 if (vhost_get_used_event(vq, &event)) {
2469 vq_err(vq, "Failed to get used event idx");
2472 return vring_need_event(vhost16_to_cpu(vq, event), new, old);
2475 /* This actually signals the guest, using eventfd. */
2476 void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2478 /* Signal the Guest tell them we used something up. */
2479 if (vq->call_ctx.ctx && vhost_notify(dev, vq))
2480 eventfd_signal(vq->call_ctx.ctx, 1);
2482 EXPORT_SYMBOL_GPL(vhost_signal);
2484 /* And here's the combo meal deal. Supersize me! */
2485 void vhost_add_used_and_signal(struct vhost_dev *dev,
2486 struct vhost_virtqueue *vq,
2487 unsigned int head, int len)
2489 vhost_add_used(vq, head, len);
2490 vhost_signal(dev, vq);
2492 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal);
2494 /* multi-buffer version of vhost_add_used_and_signal */
2495 void vhost_add_used_and_signal_n(struct vhost_dev *dev,
2496 struct vhost_virtqueue *vq,
2497 struct vring_used_elem *heads, unsigned count)
2499 vhost_add_used_n(vq, heads, count);
2500 vhost_signal(dev, vq);
2502 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
2504 /* return true if we're sure that avaiable ring is empty */
2505 bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2507 __virtio16 avail_idx;
2510 if (vq->avail_idx != vq->last_avail_idx)
2513 r = vhost_get_avail_idx(vq, &avail_idx);
2517 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2518 if (vq->avail_idx != vq->last_avail_idx) {
2519 /* Since we have updated avail_idx, the following
2520 * call to vhost_get_vq_desc() will read available
2521 * ring entries. Make sure that read happens after
2522 * the avail_idx read.
2530 EXPORT_SYMBOL_GPL(vhost_vq_avail_empty);
2532 /* OK, now we need to know about added descriptors. */
2533 bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2535 __virtio16 avail_idx;
2538 if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
2540 vq->used_flags &= ~VRING_USED_F_NO_NOTIFY;
2541 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2542 r = vhost_update_used_flags(vq);
2544 vq_err(vq, "Failed to enable notification at %p: %d\n",
2545 &vq->used->flags, r);
2549 r = vhost_update_avail_event(vq, vq->avail_idx);
2551 vq_err(vq, "Failed to update avail event index at %p: %d\n",
2552 vhost_avail_event(vq), r);
2556 /* They could have slipped one in as we were doing that: make
2557 * sure it's written, then check again. */
2559 r = vhost_get_avail_idx(vq, &avail_idx);
2561 vq_err(vq, "Failed to check avail idx at %p: %d\n",
2562 &vq->avail->idx, r);
2566 return vhost16_to_cpu(vq, avail_idx) != vq->avail_idx;
2568 EXPORT_SYMBOL_GPL(vhost_enable_notify);
2570 /* We don't need to be notified again. */
2571 void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2575 if (vq->used_flags & VRING_USED_F_NO_NOTIFY)
2577 vq->used_flags |= VRING_USED_F_NO_NOTIFY;
2578 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2579 r = vhost_update_used_flags(vq);
2581 vq_err(vq, "Failed to disable notification at %p: %d\n",
2582 &vq->used->flags, r);
2585 EXPORT_SYMBOL_GPL(vhost_disable_notify);
2587 /* Create a new message. */
2588 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type)
2590 /* Make sure all padding within the structure is initialized. */
2591 struct vhost_msg_node *node = kzalloc(sizeof(*node), GFP_KERNEL);
2596 node->msg.type = type;
2599 EXPORT_SYMBOL_GPL(vhost_new_msg);
2601 void vhost_enqueue_msg(struct vhost_dev *dev, struct list_head *head,
2602 struct vhost_msg_node *node)
2604 spin_lock(&dev->iotlb_lock);
2605 list_add_tail(&node->node, head);
2606 spin_unlock(&dev->iotlb_lock);
2608 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
2610 EXPORT_SYMBOL_GPL(vhost_enqueue_msg);
2612 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
2613 struct list_head *head)
2615 struct vhost_msg_node *node = NULL;
2617 spin_lock(&dev->iotlb_lock);
2618 if (!list_empty(head)) {
2619 node = list_first_entry(head, struct vhost_msg_node,
2621 list_del(&node->node);
2623 spin_unlock(&dev->iotlb_lock);
2627 EXPORT_SYMBOL_GPL(vhost_dequeue_msg);
2629 void vhost_set_backend_features(struct vhost_dev *dev, u64 features)
2631 struct vhost_virtqueue *vq;
2634 mutex_lock(&dev->mutex);
2635 for (i = 0; i < dev->nvqs; ++i) {
2637 mutex_lock(&vq->mutex);
2638 vq->acked_backend_features = features;
2639 mutex_unlock(&vq->mutex);
2641 mutex_unlock(&dev->mutex);
2643 EXPORT_SYMBOL_GPL(vhost_set_backend_features);
2645 static int __init vhost_init(void)
2650 static void __exit vhost_exit(void)
2654 module_init(vhost_init);
2655 module_exit(vhost_exit);
2657 MODULE_VERSION("0.0.1");
2658 MODULE_LICENSE("GPL v2");
2659 MODULE_AUTHOR("Michael S. Tsirkin");
2660 MODULE_DESCRIPTION("Host kernel accelerator for virtio");