1 /* Copyright (C) 2009 Red Hat, Inc.
2 * Copyright (C) 2006 Rusty Russell IBM Corporation
4 * Author: Michael S. Tsirkin <mst@redhat.com>
6 * Inspiration, some code, and most witty comments come from
7 * Documentation/virtual/lguest/lguest.c, by Rusty Russell
9 * This work is licensed under the terms of the GNU GPL, version 2.
11 * Generic code for virtio server in host kernel.
14 #include <linux/eventfd.h>
15 #include <linux/vhost.h>
16 #include <linux/uio.h>
18 #include <linux/mmu_context.h>
19 #include <linux/miscdevice.h>
20 #include <linux/mutex.h>
21 #include <linux/poll.h>
22 #include <linux/file.h>
23 #include <linux/highmem.h>
24 #include <linux/slab.h>
25 #include <linux/vmalloc.h>
26 #include <linux/kthread.h>
27 #include <linux/cgroup.h>
28 #include <linux/module.h>
29 #include <linux/sort.h>
30 #include <linux/sched/mm.h>
31 #include <linux/sched/signal.h>
32 #include <linux/interval_tree_generic.h>
33 #include <linux/nospec.h>
37 static ushort max_mem_regions = 64;
38 module_param(max_mem_regions, ushort, 0444);
39 MODULE_PARM_DESC(max_mem_regions,
40 "Maximum number of memory regions in memory map. (default: 64)");
41 static int max_iotlb_entries = 2048;
42 module_param(max_iotlb_entries, int, 0444);
43 MODULE_PARM_DESC(max_iotlb_entries,
44 "Maximum number of iotlb entries. (default: 2048)");
47 VHOST_MEMORY_F_LOG = 0x1,
50 #define vhost_used_event(vq) ((__virtio16 __user *)&vq->avail->ring[vq->num])
51 #define vhost_avail_event(vq) ((__virtio16 __user *)&vq->used->ring[vq->num])
53 INTERVAL_TREE_DEFINE(struct vhost_umem_node,
54 rb, __u64, __subtree_last,
55 START, LAST, static inline, vhost_umem_interval_tree);
57 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
58 static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
60 vq->user_be = !virtio_legacy_is_little_endian();
63 static void vhost_enable_cross_endian_big(struct vhost_virtqueue *vq)
68 static void vhost_enable_cross_endian_little(struct vhost_virtqueue *vq)
73 static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
75 struct vhost_vring_state s;
80 if (copy_from_user(&s, argp, sizeof(s)))
83 if (s.num != VHOST_VRING_LITTLE_ENDIAN &&
84 s.num != VHOST_VRING_BIG_ENDIAN)
87 if (s.num == VHOST_VRING_BIG_ENDIAN)
88 vhost_enable_cross_endian_big(vq);
90 vhost_enable_cross_endian_little(vq);
95 static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
98 struct vhost_vring_state s = {
103 if (copy_to_user(argp, &s, sizeof(s)))
109 static void vhost_init_is_le(struct vhost_virtqueue *vq)
111 /* Note for legacy virtio: user_be is initialized at reset time
112 * according to the host endianness. If userspace does not set an
113 * explicit endianness, the default behavior is native endian, as
114 * expected by legacy virtio.
116 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1) || !vq->user_be;
119 static void vhost_disable_cross_endian(struct vhost_virtqueue *vq)
123 static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp)
128 static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx,
134 static void vhost_init_is_le(struct vhost_virtqueue *vq)
136 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1)
137 || virtio_legacy_is_little_endian();
139 #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
141 static void vhost_reset_is_le(struct vhost_virtqueue *vq)
143 vhost_init_is_le(vq);
146 struct vhost_flush_struct {
147 struct vhost_work work;
148 struct completion wait_event;
151 static void vhost_flush_work(struct vhost_work *work)
153 struct vhost_flush_struct *s;
155 s = container_of(work, struct vhost_flush_struct, work);
156 complete(&s->wait_event);
159 static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
162 struct vhost_poll *poll;
164 poll = container_of(pt, struct vhost_poll, table);
166 add_wait_queue(wqh, &poll->wait);
169 static int vhost_poll_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync,
172 struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait);
174 if (!(key_to_poll(key) & poll->mask))
177 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)
212 mask = vfs_poll(file, &poll->table);
214 vhost_poll_wakeup(&poll->wait, 0, 0, poll_to_key(mask));
215 if (mask & EPOLLERR) {
216 vhost_poll_stop(poll);
222 EXPORT_SYMBOL_GPL(vhost_poll_start);
224 /* Stop polling a file. After this function returns, it becomes safe to drop the
225 * file reference. You must also flush afterwards. */
226 void vhost_poll_stop(struct vhost_poll *poll)
229 remove_wait_queue(poll->wqh, &poll->wait);
233 EXPORT_SYMBOL_GPL(vhost_poll_stop);
235 void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work)
237 struct vhost_flush_struct flush;
240 init_completion(&flush.wait_event);
241 vhost_work_init(&flush.work, vhost_flush_work);
243 vhost_work_queue(dev, &flush.work);
244 wait_for_completion(&flush.wait_event);
247 EXPORT_SYMBOL_GPL(vhost_work_flush);
249 /* Flush any work that has been scheduled. When calling this, don't hold any
250 * locks that are also used by the callback. */
251 void vhost_poll_flush(struct vhost_poll *poll)
253 vhost_work_flush(poll->dev, &poll->work);
255 EXPORT_SYMBOL_GPL(vhost_poll_flush);
257 void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work)
262 if (!test_and_set_bit(VHOST_WORK_QUEUED, &work->flags)) {
263 /* We can only add the work to the list after we're
264 * sure it was not in the list.
265 * test_and_set_bit() implies a memory barrier.
267 llist_add(&work->node, &dev->work_list);
268 wake_up_process(dev->worker);
271 EXPORT_SYMBOL_GPL(vhost_work_queue);
273 /* A lockless hint for busy polling code to exit the loop */
274 bool vhost_has_work(struct vhost_dev *dev)
276 return !llist_empty(&dev->work_list);
278 EXPORT_SYMBOL_GPL(vhost_has_work);
280 void vhost_poll_queue(struct vhost_poll *poll)
282 vhost_work_queue(poll->dev, &poll->work);
284 EXPORT_SYMBOL_GPL(vhost_poll_queue);
286 static void __vhost_vq_meta_reset(struct vhost_virtqueue *vq)
290 for (j = 0; j < VHOST_NUM_ADDRS; j++)
291 vq->meta_iotlb[j] = NULL;
294 static void vhost_vq_meta_reset(struct vhost_dev *d)
298 for (i = 0; i < d->nvqs; ++i)
299 __vhost_vq_meta_reset(d->vqs[i]);
302 static void vhost_vq_reset(struct vhost_dev *dev,
303 struct vhost_virtqueue *vq)
309 vq->last_avail_idx = 0;
311 vq->last_used_idx = 0;
312 vq->signalled_used = 0;
313 vq->signalled_used_valid = false;
315 vq->log_used = false;
316 vq->log_addr = -1ull;
317 vq->private_data = NULL;
318 vq->acked_features = 0;
319 vq->acked_backend_features = 0;
321 vq->error_ctx = NULL;
325 vhost_reset_is_le(vq);
326 vhost_disable_cross_endian(vq);
327 vq->busyloop_timeout = 0;
330 __vhost_vq_meta_reset(vq);
333 static int vhost_worker(void *data)
335 struct vhost_dev *dev = data;
336 struct vhost_work *work, *work_next;
337 struct llist_node *node;
338 mm_segment_t oldfs = get_fs();
344 /* mb paired w/ kthread_stop */
345 set_current_state(TASK_INTERRUPTIBLE);
347 if (kthread_should_stop()) {
348 __set_current_state(TASK_RUNNING);
352 node = llist_del_all(&dev->work_list);
356 node = llist_reverse_order(node);
357 /* make sure flag is seen after deletion */
359 llist_for_each_entry_safe(work, work_next, node, node) {
360 clear_bit(VHOST_WORK_QUEUED, &work->flags);
361 __set_current_state(TASK_RUNNING);
372 static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq)
382 /* Helper to allocate iovec buffers for all vqs. */
383 static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
385 struct vhost_virtqueue *vq;
388 for (i = 0; i < dev->nvqs; ++i) {
390 vq->indirect = kmalloc_array(UIO_MAXIOV,
391 sizeof(*vq->indirect),
393 vq->log = kmalloc_array(UIO_MAXIOV, sizeof(*vq->log),
395 vq->heads = kmalloc_array(UIO_MAXIOV, sizeof(*vq->heads),
397 if (!vq->indirect || !vq->log || !vq->heads)
404 vhost_vq_free_iovecs(dev->vqs[i]);
408 static void vhost_dev_free_iovecs(struct vhost_dev *dev)
412 for (i = 0; i < dev->nvqs; ++i)
413 vhost_vq_free_iovecs(dev->vqs[i]);
416 void vhost_dev_init(struct vhost_dev *dev,
417 struct vhost_virtqueue **vqs, int nvqs)
419 struct vhost_virtqueue *vq;
424 mutex_init(&dev->mutex);
430 init_llist_head(&dev->work_list);
431 init_waitqueue_head(&dev->wait);
432 INIT_LIST_HEAD(&dev->read_list);
433 INIT_LIST_HEAD(&dev->pending_list);
434 spin_lock_init(&dev->iotlb_lock);
437 for (i = 0; i < dev->nvqs; ++i) {
443 mutex_init(&vq->mutex);
444 vhost_vq_reset(dev, vq);
446 vhost_poll_init(&vq->poll, vq->handle_kick,
450 EXPORT_SYMBOL_GPL(vhost_dev_init);
452 /* Caller should have device mutex */
453 long vhost_dev_check_owner(struct vhost_dev *dev)
455 /* Are you the owner? If not, I don't think you mean to do that */
456 return dev->mm == current->mm ? 0 : -EPERM;
458 EXPORT_SYMBOL_GPL(vhost_dev_check_owner);
460 struct vhost_attach_cgroups_struct {
461 struct vhost_work work;
462 struct task_struct *owner;
466 static void vhost_attach_cgroups_work(struct vhost_work *work)
468 struct vhost_attach_cgroups_struct *s;
470 s = container_of(work, struct vhost_attach_cgroups_struct, work);
471 s->ret = cgroup_attach_task_all(s->owner, current);
474 static int vhost_attach_cgroups(struct vhost_dev *dev)
476 struct vhost_attach_cgroups_struct attach;
478 attach.owner = current;
479 vhost_work_init(&attach.work, vhost_attach_cgroups_work);
480 vhost_work_queue(dev, &attach.work);
481 vhost_work_flush(dev, &attach.work);
485 /* Caller should have device mutex */
486 bool vhost_dev_has_owner(struct vhost_dev *dev)
490 EXPORT_SYMBOL_GPL(vhost_dev_has_owner);
492 /* Caller should have device mutex */
493 long vhost_dev_set_owner(struct vhost_dev *dev)
495 struct task_struct *worker;
498 /* Is there an owner already? */
499 if (vhost_dev_has_owner(dev)) {
504 /* No owner, become one */
505 dev->mm = get_task_mm(current);
506 worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid);
507 if (IS_ERR(worker)) {
508 err = PTR_ERR(worker);
512 dev->worker = worker;
513 wake_up_process(worker); /* avoid contributing to loadavg */
515 err = vhost_attach_cgroups(dev);
519 err = vhost_dev_alloc_iovecs(dev);
525 kthread_stop(worker);
534 EXPORT_SYMBOL_GPL(vhost_dev_set_owner);
536 struct vhost_umem *vhost_dev_reset_owner_prepare(void)
538 return kvzalloc(sizeof(struct vhost_umem), GFP_KERNEL);
540 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare);
542 /* Caller should have device mutex */
543 void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_umem *umem)
547 vhost_dev_cleanup(dev);
549 /* Restore memory to default empty mapping. */
550 INIT_LIST_HEAD(&umem->umem_list);
552 /* We don't need VQ locks below since vhost_dev_cleanup makes sure
553 * VQs aren't running.
555 for (i = 0; i < dev->nvqs; ++i)
556 dev->vqs[i]->umem = umem;
558 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner);
560 void vhost_dev_stop(struct vhost_dev *dev)
564 for (i = 0; i < dev->nvqs; ++i) {
565 if (dev->vqs[i]->kick && dev->vqs[i]->handle_kick) {
566 vhost_poll_stop(&dev->vqs[i]->poll);
567 vhost_poll_flush(&dev->vqs[i]->poll);
571 EXPORT_SYMBOL_GPL(vhost_dev_stop);
573 static void vhost_umem_free(struct vhost_umem *umem,
574 struct vhost_umem_node *node)
576 vhost_umem_interval_tree_remove(node, &umem->umem_tree);
577 list_del(&node->link);
582 static void vhost_umem_clean(struct vhost_umem *umem)
584 struct vhost_umem_node *node, *tmp;
589 list_for_each_entry_safe(node, tmp, &umem->umem_list, link)
590 vhost_umem_free(umem, node);
595 static void vhost_clear_msg(struct vhost_dev *dev)
597 struct vhost_msg_node *node, *n;
599 spin_lock(&dev->iotlb_lock);
601 list_for_each_entry_safe(node, n, &dev->read_list, node) {
602 list_del(&node->node);
606 list_for_each_entry_safe(node, n, &dev->pending_list, node) {
607 list_del(&node->node);
611 spin_unlock(&dev->iotlb_lock);
614 void vhost_dev_cleanup(struct vhost_dev *dev)
618 for (i = 0; i < dev->nvqs; ++i) {
619 if (dev->vqs[i]->error_ctx)
620 eventfd_ctx_put(dev->vqs[i]->error_ctx);
621 if (dev->vqs[i]->kick)
622 fput(dev->vqs[i]->kick);
623 if (dev->vqs[i]->call_ctx)
624 eventfd_ctx_put(dev->vqs[i]->call_ctx);
625 vhost_vq_reset(dev, dev->vqs[i]);
627 vhost_dev_free_iovecs(dev);
629 eventfd_ctx_put(dev->log_ctx);
631 /* No one will access memory at this point */
632 vhost_umem_clean(dev->umem);
634 vhost_umem_clean(dev->iotlb);
636 vhost_clear_msg(dev);
637 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
638 WARN_ON(!llist_empty(&dev->work_list));
640 kthread_stop(dev->worker);
647 EXPORT_SYMBOL_GPL(vhost_dev_cleanup);
649 static bool log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
651 u64 a = addr / VHOST_PAGE_SIZE / 8;
653 /* Make sure 64 bit math will not overflow. */
654 if (a > ULONG_MAX - (unsigned long)log_base ||
655 a + (unsigned long)log_base > ULONG_MAX)
658 return access_ok(log_base + a,
659 (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8);
662 static bool vhost_overflow(u64 uaddr, u64 size)
664 /* Make sure 64 bit math will not overflow. */
665 return uaddr > ULONG_MAX || size > ULONG_MAX || uaddr > ULONG_MAX - size;
668 /* Caller should have vq mutex and device mutex. */
669 static bool vq_memory_access_ok(void __user *log_base, struct vhost_umem *umem,
672 struct vhost_umem_node *node;
677 list_for_each_entry(node, &umem->umem_list, link) {
678 unsigned long a = node->userspace_addr;
680 if (vhost_overflow(node->userspace_addr, node->size))
684 if (!access_ok((void __user *)a,
687 else if (log_all && !log_access_ok(log_base,
695 static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq,
696 u64 addr, unsigned int size,
699 const struct vhost_umem_node *node = vq->meta_iotlb[type];
704 return (void *)(uintptr_t)(node->userspace_addr + addr - node->start);
707 /* Can we switch to this memory table? */
708 /* Caller should have device mutex but not vq mutex */
709 static bool memory_access_ok(struct vhost_dev *d, struct vhost_umem *umem,
714 for (i = 0; i < d->nvqs; ++i) {
718 mutex_lock(&d->vqs[i]->mutex);
719 log = log_all || vhost_has_feature(d->vqs[i], VHOST_F_LOG_ALL);
720 /* If ring is inactive, will check when it's enabled. */
721 if (d->vqs[i]->private_data)
722 ok = vq_memory_access_ok(d->vqs[i]->log_base,
726 mutex_unlock(&d->vqs[i]->mutex);
733 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
734 struct iovec iov[], int iov_size, int access);
736 static int vhost_copy_to_user(struct vhost_virtqueue *vq, void __user *to,
737 const void *from, unsigned size)
742 return __copy_to_user(to, from, size);
744 /* This function should be called after iotlb
745 * prefetch, which means we're sure that all vq
746 * could be access through iotlb. So -EAGAIN should
747 * not happen in this case.
750 void __user *uaddr = vhost_vq_meta_fetch(vq,
751 (u64)(uintptr_t)to, size,
755 return __copy_to_user(uaddr, from, size);
757 ret = translate_desc(vq, (u64)(uintptr_t)to, size, vq->iotlb_iov,
758 ARRAY_SIZE(vq->iotlb_iov),
762 iov_iter_init(&t, WRITE, vq->iotlb_iov, ret, size);
763 ret = copy_to_iter(from, size, &t);
771 static int vhost_copy_from_user(struct vhost_virtqueue *vq, void *to,
772 void __user *from, unsigned size)
777 return __copy_from_user(to, from, size);
779 /* This function should be called after iotlb
780 * prefetch, which means we're sure that vq
781 * could be access through iotlb. So -EAGAIN should
782 * not happen in this case.
784 void __user *uaddr = vhost_vq_meta_fetch(vq,
785 (u64)(uintptr_t)from, size,
790 return __copy_from_user(to, uaddr, size);
792 ret = translate_desc(vq, (u64)(uintptr_t)from, size, vq->iotlb_iov,
793 ARRAY_SIZE(vq->iotlb_iov),
796 vq_err(vq, "IOTLB translation failure: uaddr "
797 "%p size 0x%llx\n", from,
798 (unsigned long long) size);
801 iov_iter_init(&f, READ, vq->iotlb_iov, ret, size);
802 ret = copy_from_iter(to, size, &f);
811 static void __user *__vhost_get_user_slow(struct vhost_virtqueue *vq,
812 void __user *addr, unsigned int size,
817 ret = translate_desc(vq, (u64)(uintptr_t)addr, size, vq->iotlb_iov,
818 ARRAY_SIZE(vq->iotlb_iov),
821 vq_err(vq, "IOTLB translation failure: uaddr "
822 "%p size 0x%llx\n", addr,
823 (unsigned long long) size);
827 if (ret != 1 || vq->iotlb_iov[0].iov_len != size) {
828 vq_err(vq, "Non atomic userspace memory access: uaddr "
829 "%p size 0x%llx\n", addr,
830 (unsigned long long) size);
834 return vq->iotlb_iov[0].iov_base;
837 /* This function should be called after iotlb
838 * prefetch, which means we're sure that vq
839 * could be access through iotlb. So -EAGAIN should
840 * not happen in this case.
842 static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq,
843 void *addr, unsigned int size,
846 void __user *uaddr = vhost_vq_meta_fetch(vq,
847 (u64)(uintptr_t)addr, size, type);
851 return __vhost_get_user_slow(vq, addr, size, type);
854 #define vhost_put_user(vq, x, ptr) \
858 ret = __put_user(x, ptr); \
860 __typeof__(ptr) to = \
861 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
862 sizeof(*ptr), VHOST_ADDR_USED); \
864 ret = __put_user(x, to); \
871 #define vhost_get_user(vq, x, ptr, type) \
875 ret = __get_user(x, ptr); \
877 __typeof__(ptr) from = \
878 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
882 ret = __get_user(x, from); \
889 #define vhost_get_avail(vq, x, ptr) \
890 vhost_get_user(vq, x, ptr, VHOST_ADDR_AVAIL)
892 #define vhost_get_used(vq, x, ptr) \
893 vhost_get_user(vq, x, ptr, VHOST_ADDR_USED)
895 static void vhost_dev_lock_vqs(struct vhost_dev *d)
898 for (i = 0; i < d->nvqs; ++i)
899 mutex_lock_nested(&d->vqs[i]->mutex, i);
902 static void vhost_dev_unlock_vqs(struct vhost_dev *d)
905 for (i = 0; i < d->nvqs; ++i)
906 mutex_unlock(&d->vqs[i]->mutex);
909 static int vhost_new_umem_range(struct vhost_umem *umem,
910 u64 start, u64 size, u64 end,
911 u64 userspace_addr, int perm)
913 struct vhost_umem_node *tmp, *node = kmalloc(sizeof(*node), GFP_ATOMIC);
918 if (umem->numem == max_iotlb_entries) {
919 tmp = list_first_entry(&umem->umem_list, typeof(*tmp), link);
920 vhost_umem_free(umem, tmp);
926 node->userspace_addr = userspace_addr;
928 INIT_LIST_HEAD(&node->link);
929 list_add_tail(&node->link, &umem->umem_list);
930 vhost_umem_interval_tree_insert(node, &umem->umem_tree);
936 static void vhost_del_umem_range(struct vhost_umem *umem,
939 struct vhost_umem_node *node;
941 while ((node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
943 vhost_umem_free(umem, node);
946 static void vhost_iotlb_notify_vq(struct vhost_dev *d,
947 struct vhost_iotlb_msg *msg)
949 struct vhost_msg_node *node, *n;
951 spin_lock(&d->iotlb_lock);
953 list_for_each_entry_safe(node, n, &d->pending_list, node) {
954 struct vhost_iotlb_msg *vq_msg = &node->msg.iotlb;
955 if (msg->iova <= vq_msg->iova &&
956 msg->iova + msg->size - 1 >= vq_msg->iova &&
957 vq_msg->type == VHOST_IOTLB_MISS) {
958 vhost_poll_queue(&node->vq->poll);
959 list_del(&node->node);
964 spin_unlock(&d->iotlb_lock);
967 static bool umem_access_ok(u64 uaddr, u64 size, int access)
969 unsigned long a = uaddr;
971 /* Make sure 64 bit math will not overflow. */
972 if (vhost_overflow(uaddr, size))
975 if ((access & VHOST_ACCESS_RO) &&
976 !access_ok((void __user *)a, size))
978 if ((access & VHOST_ACCESS_WO) &&
979 !access_ok((void __user *)a, size))
984 static int vhost_process_iotlb_msg(struct vhost_dev *dev,
985 struct vhost_iotlb_msg *msg)
989 mutex_lock(&dev->mutex);
990 vhost_dev_lock_vqs(dev);
992 case VHOST_IOTLB_UPDATE:
997 if (!umem_access_ok(msg->uaddr, msg->size, msg->perm)) {
1001 vhost_vq_meta_reset(dev);
1002 if (vhost_new_umem_range(dev->iotlb, msg->iova, msg->size,
1003 msg->iova + msg->size - 1,
1004 msg->uaddr, msg->perm)) {
1008 vhost_iotlb_notify_vq(dev, msg);
1010 case VHOST_IOTLB_INVALIDATE:
1015 vhost_vq_meta_reset(dev);
1016 vhost_del_umem_range(dev->iotlb, msg->iova,
1017 msg->iova + msg->size - 1);
1024 vhost_dev_unlock_vqs(dev);
1025 mutex_unlock(&dev->mutex);
1029 ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
1030 struct iov_iter *from)
1032 struct vhost_iotlb_msg msg;
1036 ret = copy_from_iter(&type, sizeof(type), from);
1037 if (ret != sizeof(type)) {
1043 case VHOST_IOTLB_MSG:
1044 /* There maybe a hole after type for V1 message type,
1047 offset = offsetof(struct vhost_msg, iotlb) - sizeof(int);
1049 case VHOST_IOTLB_MSG_V2:
1050 offset = sizeof(__u32);
1057 iov_iter_advance(from, offset);
1058 ret = copy_from_iter(&msg, sizeof(msg), from);
1059 if (ret != sizeof(msg)) {
1063 if (vhost_process_iotlb_msg(dev, &msg)) {
1068 ret = (type == VHOST_IOTLB_MSG) ? sizeof(struct vhost_msg) :
1069 sizeof(struct vhost_msg_v2);
1073 EXPORT_SYMBOL(vhost_chr_write_iter);
1075 __poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
1080 poll_wait(file, &dev->wait, wait);
1082 if (!list_empty(&dev->read_list))
1083 mask |= EPOLLIN | EPOLLRDNORM;
1087 EXPORT_SYMBOL(vhost_chr_poll);
1089 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
1093 struct vhost_msg_node *node;
1095 unsigned size = sizeof(struct vhost_msg);
1097 if (iov_iter_count(to) < size)
1102 prepare_to_wait(&dev->wait, &wait,
1103 TASK_INTERRUPTIBLE);
1105 node = vhost_dequeue_msg(dev, &dev->read_list);
1112 if (signal_pending(current)) {
1125 finish_wait(&dev->wait, &wait);
1128 struct vhost_iotlb_msg *msg;
1129 void *start = &node->msg;
1131 switch (node->msg.type) {
1132 case VHOST_IOTLB_MSG:
1133 size = sizeof(node->msg);
1134 msg = &node->msg.iotlb;
1136 case VHOST_IOTLB_MSG_V2:
1137 size = sizeof(node->msg_v2);
1138 msg = &node->msg_v2.iotlb;
1145 ret = copy_to_iter(start, size, to);
1146 if (ret != size || msg->type != VHOST_IOTLB_MISS) {
1150 vhost_enqueue_msg(dev, &dev->pending_list, node);
1155 EXPORT_SYMBOL_GPL(vhost_chr_read_iter);
1157 static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access)
1159 struct vhost_dev *dev = vq->dev;
1160 struct vhost_msg_node *node;
1161 struct vhost_iotlb_msg *msg;
1162 bool v2 = vhost_backend_has_feature(vq, VHOST_BACKEND_F_IOTLB_MSG_V2);
1164 node = vhost_new_msg(vq, v2 ? VHOST_IOTLB_MSG_V2 : VHOST_IOTLB_MSG);
1169 node->msg_v2.type = VHOST_IOTLB_MSG_V2;
1170 msg = &node->msg_v2.iotlb;
1172 msg = &node->msg.iotlb;
1175 msg->type = VHOST_IOTLB_MISS;
1179 vhost_enqueue_msg(dev, &dev->read_list, node);
1184 static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
1185 struct vring_desc __user *desc,
1186 struct vring_avail __user *avail,
1187 struct vring_used __user *used)
1190 size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
1192 return access_ok(desc, num * sizeof *desc) &&
1194 sizeof *avail + num * sizeof *avail->ring + s) &&
1196 sizeof *used + num * sizeof *used->ring + s);
1199 static void vhost_vq_meta_update(struct vhost_virtqueue *vq,
1200 const struct vhost_umem_node *node,
1203 int access = (type == VHOST_ADDR_USED) ?
1204 VHOST_ACCESS_WO : VHOST_ACCESS_RO;
1206 if (likely(node->perm & access))
1207 vq->meta_iotlb[type] = node;
1210 static bool iotlb_access_ok(struct vhost_virtqueue *vq,
1211 int access, u64 addr, u64 len, int type)
1213 const struct vhost_umem_node *node;
1214 struct vhost_umem *umem = vq->iotlb;
1215 u64 s = 0, size, orig_addr = addr, last = addr + len - 1;
1217 if (vhost_vq_meta_fetch(vq, addr, len, type))
1221 node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
1224 if (node == NULL || node->start > addr) {
1225 vhost_iotlb_miss(vq, addr, access);
1227 } else if (!(node->perm & access)) {
1228 /* Report the possible access violation by
1229 * request another translation from userspace.
1234 size = node->size - addr + node->start;
1236 if (orig_addr == addr && size >= len)
1237 vhost_vq_meta_update(vq, node, type);
1246 int vq_iotlb_prefetch(struct vhost_virtqueue *vq)
1248 size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
1249 unsigned int num = vq->num;
1254 return iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->desc,
1255 num * sizeof(*vq->desc), VHOST_ADDR_DESC) &&
1256 iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->avail,
1258 num * sizeof(*vq->avail->ring) + s,
1259 VHOST_ADDR_AVAIL) &&
1260 iotlb_access_ok(vq, VHOST_ACCESS_WO, (u64)(uintptr_t)vq->used,
1262 num * sizeof(*vq->used->ring) + s,
1265 EXPORT_SYMBOL_GPL(vq_iotlb_prefetch);
1267 /* Can we log writes? */
1268 /* Caller should have device mutex but not vq mutex */
1269 bool vhost_log_access_ok(struct vhost_dev *dev)
1271 return memory_access_ok(dev, dev->umem, 1);
1273 EXPORT_SYMBOL_GPL(vhost_log_access_ok);
1275 /* Verify access for write logging. */
1276 /* Caller should have vq mutex and device mutex */
1277 static bool vq_log_access_ok(struct vhost_virtqueue *vq,
1278 void __user *log_base)
1280 size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
1282 return vq_memory_access_ok(log_base, vq->umem,
1283 vhost_has_feature(vq, VHOST_F_LOG_ALL)) &&
1284 (!vq->log_used || log_access_ok(log_base, vq->log_addr,
1286 vq->num * sizeof *vq->used->ring + s));
1289 /* Can we start vq? */
1290 /* Caller should have vq mutex and device mutex */
1291 bool vhost_vq_access_ok(struct vhost_virtqueue *vq)
1293 if (!vq_log_access_ok(vq, vq->log_base))
1296 /* Access validation occurs at prefetch time with IOTLB */
1300 return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used);
1302 EXPORT_SYMBOL_GPL(vhost_vq_access_ok);
1304 static struct vhost_umem *vhost_umem_alloc(void)
1306 struct vhost_umem *umem = kvzalloc(sizeof(*umem), GFP_KERNEL);
1311 umem->umem_tree = RB_ROOT_CACHED;
1313 INIT_LIST_HEAD(&umem->umem_list);
1318 static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
1320 struct vhost_memory mem, *newmem;
1321 struct vhost_memory_region *region;
1322 struct vhost_umem *newumem, *oldumem;
1323 unsigned long size = offsetof(struct vhost_memory, regions);
1326 if (copy_from_user(&mem, m, size))
1330 if (mem.nregions > max_mem_regions)
1332 newmem = kvzalloc(struct_size(newmem, regions, mem.nregions),
1337 memcpy(newmem, &mem, size);
1338 if (copy_from_user(newmem->regions, m->regions,
1339 mem.nregions * sizeof *m->regions)) {
1344 newumem = vhost_umem_alloc();
1350 for (region = newmem->regions;
1351 region < newmem->regions + mem.nregions;
1353 if (vhost_new_umem_range(newumem,
1354 region->guest_phys_addr,
1355 region->memory_size,
1356 region->guest_phys_addr +
1357 region->memory_size - 1,
1358 region->userspace_addr,
1363 if (!memory_access_ok(d, newumem, 0))
1369 /* All memory accesses are done under some VQ mutex. */
1370 for (i = 0; i < d->nvqs; ++i) {
1371 mutex_lock(&d->vqs[i]->mutex);
1372 d->vqs[i]->umem = newumem;
1373 mutex_unlock(&d->vqs[i]->mutex);
1377 vhost_umem_clean(oldumem);
1381 vhost_umem_clean(newumem);
1386 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
1388 struct file *eventfp, *filep = NULL;
1389 bool pollstart = false, pollstop = false;
1390 struct eventfd_ctx *ctx = NULL;
1391 u32 __user *idxp = argp;
1392 struct vhost_virtqueue *vq;
1393 struct vhost_vring_state s;
1394 struct vhost_vring_file f;
1395 struct vhost_vring_addr a;
1399 r = get_user(idx, idxp);
1405 idx = array_index_nospec(idx, d->nvqs);
1408 mutex_lock(&vq->mutex);
1411 case VHOST_SET_VRING_NUM:
1412 /* Resizing ring with an active backend?
1413 * You don't want to do that. */
1414 if (vq->private_data) {
1418 if (copy_from_user(&s, argp, sizeof s)) {
1422 if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) {
1428 case VHOST_SET_VRING_BASE:
1429 /* Moving base with an active backend?
1430 * You don't want to do that. */
1431 if (vq->private_data) {
1435 if (copy_from_user(&s, argp, sizeof s)) {
1439 if (s.num > 0xffff) {
1443 vq->last_avail_idx = s.num;
1444 /* Forget the cached index value. */
1445 vq->avail_idx = vq->last_avail_idx;
1447 case VHOST_GET_VRING_BASE:
1449 s.num = vq->last_avail_idx;
1450 if (copy_to_user(argp, &s, sizeof s))
1453 case VHOST_SET_VRING_ADDR:
1454 if (copy_from_user(&a, argp, sizeof a)) {
1458 if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) {
1462 /* For 32bit, verify that the top 32bits of the user
1463 data are set to zero. */
1464 if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr ||
1465 (u64)(unsigned long)a.used_user_addr != a.used_user_addr ||
1466 (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) {
1471 /* Make sure it's safe to cast pointers to vring types. */
1472 BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE);
1473 BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE);
1474 if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) ||
1475 (a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) ||
1476 (a.log_guest_addr & (VRING_USED_ALIGN_SIZE - 1))) {
1481 /* We only verify access here if backend is configured.
1482 * If it is not, we don't as size might not have been setup.
1483 * We will verify when backend is configured. */
1484 if (vq->private_data) {
1485 if (!vq_access_ok(vq, vq->num,
1486 (void __user *)(unsigned long)a.desc_user_addr,
1487 (void __user *)(unsigned long)a.avail_user_addr,
1488 (void __user *)(unsigned long)a.used_user_addr)) {
1493 /* Also validate log access for used ring if enabled. */
1494 if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) &&
1495 !log_access_ok(vq->log_base, a.log_guest_addr,
1497 vq->num * sizeof *vq->used->ring)) {
1503 vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG));
1504 vq->desc = (void __user *)(unsigned long)a.desc_user_addr;
1505 vq->avail = (void __user *)(unsigned long)a.avail_user_addr;
1506 vq->log_addr = a.log_guest_addr;
1507 vq->used = (void __user *)(unsigned long)a.used_user_addr;
1509 case VHOST_SET_VRING_KICK:
1510 if (copy_from_user(&f, argp, sizeof f)) {
1514 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
1515 if (IS_ERR(eventfp)) {
1516 r = PTR_ERR(eventfp);
1519 if (eventfp != vq->kick) {
1520 pollstop = (filep = vq->kick) != NULL;
1521 pollstart = (vq->kick = eventfp) != NULL;
1525 case VHOST_SET_VRING_CALL:
1526 if (copy_from_user(&f, argp, sizeof f)) {
1530 ctx = f.fd == -1 ? NULL : eventfd_ctx_fdget(f.fd);
1535 swap(ctx, vq->call_ctx);
1537 case VHOST_SET_VRING_ERR:
1538 if (copy_from_user(&f, argp, sizeof f)) {
1542 ctx = f.fd == -1 ? NULL : eventfd_ctx_fdget(f.fd);
1547 swap(ctx, vq->error_ctx);
1549 case VHOST_SET_VRING_ENDIAN:
1550 r = vhost_set_vring_endian(vq, argp);
1552 case VHOST_GET_VRING_ENDIAN:
1553 r = vhost_get_vring_endian(vq, idx, argp);
1555 case VHOST_SET_VRING_BUSYLOOP_TIMEOUT:
1556 if (copy_from_user(&s, argp, sizeof(s))) {
1560 vq->busyloop_timeout = s.num;
1562 case VHOST_GET_VRING_BUSYLOOP_TIMEOUT:
1564 s.num = vq->busyloop_timeout;
1565 if (copy_to_user(argp, &s, sizeof(s)))
1572 if (pollstop && vq->handle_kick)
1573 vhost_poll_stop(&vq->poll);
1575 if (!IS_ERR_OR_NULL(ctx))
1576 eventfd_ctx_put(ctx);
1580 if (pollstart && vq->handle_kick)
1581 r = vhost_poll_start(&vq->poll, vq->kick);
1583 mutex_unlock(&vq->mutex);
1585 if (pollstop && vq->handle_kick)
1586 vhost_poll_flush(&vq->poll);
1589 EXPORT_SYMBOL_GPL(vhost_vring_ioctl);
1591 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled)
1593 struct vhost_umem *niotlb, *oiotlb;
1596 niotlb = vhost_umem_alloc();
1603 for (i = 0; i < d->nvqs; ++i) {
1604 struct vhost_virtqueue *vq = d->vqs[i];
1606 mutex_lock(&vq->mutex);
1608 __vhost_vq_meta_reset(vq);
1609 mutex_unlock(&vq->mutex);
1612 vhost_umem_clean(oiotlb);
1616 EXPORT_SYMBOL_GPL(vhost_init_device_iotlb);
1618 /* Caller must have device mutex */
1619 long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
1621 struct eventfd_ctx *ctx;
1626 /* If you are not the owner, you can become one */
1627 if (ioctl == VHOST_SET_OWNER) {
1628 r = vhost_dev_set_owner(d);
1632 /* You must be the owner to do anything else */
1633 r = vhost_dev_check_owner(d);
1638 case VHOST_SET_MEM_TABLE:
1639 r = vhost_set_memory(d, argp);
1641 case VHOST_SET_LOG_BASE:
1642 if (copy_from_user(&p, argp, sizeof p)) {
1646 if ((u64)(unsigned long)p != p) {
1650 for (i = 0; i < d->nvqs; ++i) {
1651 struct vhost_virtqueue *vq;
1652 void __user *base = (void __user *)(unsigned long)p;
1654 mutex_lock(&vq->mutex);
1655 /* If ring is inactive, will check when it's enabled. */
1656 if (vq->private_data && !vq_log_access_ok(vq, base))
1659 vq->log_base = base;
1660 mutex_unlock(&vq->mutex);
1663 case VHOST_SET_LOG_FD:
1664 r = get_user(fd, (int __user *)argp);
1667 ctx = fd == -1 ? NULL : eventfd_ctx_fdget(fd);
1672 swap(ctx, d->log_ctx);
1673 for (i = 0; i < d->nvqs; ++i) {
1674 mutex_lock(&d->vqs[i]->mutex);
1675 d->vqs[i]->log_ctx = d->log_ctx;
1676 mutex_unlock(&d->vqs[i]->mutex);
1679 eventfd_ctx_put(ctx);
1688 EXPORT_SYMBOL_GPL(vhost_dev_ioctl);
1690 /* TODO: This is really inefficient. We need something like get_user()
1691 * (instruction directly accesses the data, with an exception table entry
1692 * returning -EFAULT). See Documentation/x86/exception-tables.txt.
1694 static int set_bit_to_user(int nr, void __user *addr)
1696 unsigned long log = (unsigned long)addr;
1699 int bit = nr + (log % PAGE_SIZE) * 8;
1702 r = get_user_pages_fast(log, 1, 1, &page);
1706 base = kmap_atomic(page);
1708 kunmap_atomic(base);
1709 set_page_dirty_lock(page);
1714 static int log_write(void __user *log_base,
1715 u64 write_address, u64 write_length)
1717 u64 write_page = write_address / VHOST_PAGE_SIZE;
1722 write_length += write_address % VHOST_PAGE_SIZE;
1724 u64 base = (u64)(unsigned long)log_base;
1725 u64 log = base + write_page / 8;
1726 int bit = write_page % 8;
1727 if ((u64)(unsigned long)log != log)
1729 r = set_bit_to_user(bit, (void __user *)(unsigned long)log);
1732 if (write_length <= VHOST_PAGE_SIZE)
1734 write_length -= VHOST_PAGE_SIZE;
1740 static int log_write_hva(struct vhost_virtqueue *vq, u64 hva, u64 len)
1742 struct vhost_umem *umem = vq->umem;
1743 struct vhost_umem_node *u;
1744 u64 start, end, l, min;
1750 /* More than one GPAs can be mapped into a single HVA. So
1751 * iterate all possible umems here to be safe.
1753 list_for_each_entry(u, &umem->umem_list, link) {
1754 if (u->userspace_addr > hva - 1 + len ||
1755 u->userspace_addr - 1 + u->size < hva)
1757 start = max(u->userspace_addr, hva);
1758 end = min(u->userspace_addr - 1 + u->size,
1760 l = end - start + 1;
1761 r = log_write(vq->log_base,
1762 u->start + start - u->userspace_addr,
1780 static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len)
1782 struct iovec iov[64];
1786 return log_write(vq->log_base, vq->log_addr + used_offset, len);
1788 ret = translate_desc(vq, (uintptr_t)vq->used + used_offset,
1789 len, iov, 64, VHOST_ACCESS_WO);
1793 for (i = 0; i < ret; i++) {
1794 ret = log_write_hva(vq, (uintptr_t)iov[i].iov_base,
1803 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
1804 unsigned int log_num, u64 len, struct iovec *iov, int count)
1808 /* Make sure data written is seen before log. */
1812 for (i = 0; i < count; i++) {
1813 r = log_write_hva(vq, (uintptr_t)iov[i].iov_base,
1821 for (i = 0; i < log_num; ++i) {
1822 u64 l = min(log[i].len, len);
1823 r = log_write(vq->log_base, log[i].addr, l);
1829 eventfd_signal(vq->log_ctx, 1);
1833 /* Length written exceeds what we have stored. This is a bug. */
1837 EXPORT_SYMBOL_GPL(vhost_log_write);
1839 static int vhost_update_used_flags(struct vhost_virtqueue *vq)
1842 if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags),
1843 &vq->used->flags) < 0)
1845 if (unlikely(vq->log_used)) {
1846 /* Make sure the flag is seen before log. */
1848 /* Log used flag write. */
1849 used = &vq->used->flags;
1850 log_used(vq, (used - (void __user *)vq->used),
1851 sizeof vq->used->flags);
1853 eventfd_signal(vq->log_ctx, 1);
1858 static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
1860 if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx),
1861 vhost_avail_event(vq)))
1863 if (unlikely(vq->log_used)) {
1865 /* Make sure the event is seen before log. */
1867 /* Log avail event write */
1868 used = vhost_avail_event(vq);
1869 log_used(vq, (used - (void __user *)vq->used),
1870 sizeof *vhost_avail_event(vq));
1872 eventfd_signal(vq->log_ctx, 1);
1877 int vhost_vq_init_access(struct vhost_virtqueue *vq)
1879 __virtio16 last_used_idx;
1881 bool is_le = vq->is_le;
1883 if (!vq->private_data)
1886 vhost_init_is_le(vq);
1888 r = vhost_update_used_flags(vq);
1891 vq->signalled_used_valid = false;
1893 !access_ok(&vq->used->idx, sizeof vq->used->idx)) {
1897 r = vhost_get_used(vq, last_used_idx, &vq->used->idx);
1899 vq_err(vq, "Can't access used idx at %p\n",
1903 vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx);
1910 EXPORT_SYMBOL_GPL(vhost_vq_init_access);
1912 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
1913 struct iovec iov[], int iov_size, int access)
1915 const struct vhost_umem_node *node;
1916 struct vhost_dev *dev = vq->dev;
1917 struct vhost_umem *umem = dev->iotlb ? dev->iotlb : dev->umem;
1922 while ((u64)len > s) {
1924 if (unlikely(ret >= iov_size)) {
1929 node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
1930 addr, addr + len - 1);
1931 if (node == NULL || node->start > addr) {
1932 if (umem != dev->iotlb) {
1938 } else if (!(node->perm & access)) {
1944 size = node->size - addr + node->start;
1945 _iov->iov_len = min((u64)len - s, size);
1946 _iov->iov_base = (void __user *)(unsigned long)
1947 (node->userspace_addr + addr - node->start);
1954 vhost_iotlb_miss(vq, addr, access);
1958 /* Each buffer in the virtqueues is actually a chain of descriptors. This
1959 * function returns the next descriptor in the chain,
1960 * or -1U if we're at the end. */
1961 static unsigned next_desc(struct vhost_virtqueue *vq, struct vring_desc *desc)
1965 /* If this descriptor says it doesn't chain, we're done. */
1966 if (!(desc->flags & cpu_to_vhost16(vq, VRING_DESC_F_NEXT)))
1969 /* Check they're not leading us off end of descriptors. */
1970 next = vhost16_to_cpu(vq, READ_ONCE(desc->next));
1974 static int get_indirect(struct vhost_virtqueue *vq,
1975 struct iovec iov[], unsigned int iov_size,
1976 unsigned int *out_num, unsigned int *in_num,
1977 struct vhost_log *log, unsigned int *log_num,
1978 struct vring_desc *indirect)
1980 struct vring_desc desc;
1981 unsigned int i = 0, count, found = 0;
1982 u32 len = vhost32_to_cpu(vq, indirect->len);
1983 struct iov_iter from;
1987 if (unlikely(len % sizeof desc)) {
1988 vq_err(vq, "Invalid length in indirect descriptor: "
1989 "len 0x%llx not multiple of 0x%zx\n",
1990 (unsigned long long)len,
1995 ret = translate_desc(vq, vhost64_to_cpu(vq, indirect->addr), len, vq->indirect,
1996 UIO_MAXIOV, VHOST_ACCESS_RO);
1997 if (unlikely(ret < 0)) {
1999 vq_err(vq, "Translation failure %d in indirect.\n", ret);
2002 iov_iter_init(&from, READ, vq->indirect, ret, len);
2004 /* We will use the result as an address to read from, so most
2005 * architectures only need a compiler barrier here. */
2006 read_barrier_depends();
2008 count = len / sizeof desc;
2009 /* Buffers are chained via a 16 bit next field, so
2010 * we can have at most 2^16 of these. */
2011 if (unlikely(count > USHRT_MAX + 1)) {
2012 vq_err(vq, "Indirect buffer length too big: %d\n",
2018 unsigned iov_count = *in_num + *out_num;
2019 if (unlikely(++found > count)) {
2020 vq_err(vq, "Loop detected: last one at %u "
2021 "indirect size %u\n",
2025 if (unlikely(!copy_from_iter_full(&desc, sizeof(desc), &from))) {
2026 vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
2027 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
2030 if (unlikely(desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT))) {
2031 vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n",
2032 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
2036 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
2037 access = VHOST_ACCESS_WO;
2039 access = VHOST_ACCESS_RO;
2041 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
2042 vhost32_to_cpu(vq, desc.len), iov + iov_count,
2043 iov_size - iov_count, access);
2044 if (unlikely(ret < 0)) {
2046 vq_err(vq, "Translation failure %d indirect idx %d\n",
2050 /* If this is an input descriptor, increment that count. */
2051 if (access == VHOST_ACCESS_WO) {
2053 if (unlikely(log)) {
2054 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
2055 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
2059 /* If it's an output descriptor, they're all supposed
2060 * to come before any input descriptors. */
2061 if (unlikely(*in_num)) {
2062 vq_err(vq, "Indirect descriptor "
2063 "has out after in: idx %d\n", i);
2068 } while ((i = next_desc(vq, &desc)) != -1);
2072 /* This looks in the virtqueue and for the first available buffer, and converts
2073 * it to an iovec for convenient access. Since descriptors consist of some
2074 * number of output then some number of input descriptors, it's actually two
2075 * iovecs, but we pack them into one and note how many of each there were.
2077 * This function returns the descriptor number found, or vq->num (which is
2078 * never a valid descriptor number) if none was found. A negative code is
2079 * returned on error. */
2080 int vhost_get_vq_desc(struct vhost_virtqueue *vq,
2081 struct iovec iov[], unsigned int iov_size,
2082 unsigned int *out_num, unsigned int *in_num,
2083 struct vhost_log *log, unsigned int *log_num)
2085 struct vring_desc desc;
2086 unsigned int i, head, found = 0;
2088 __virtio16 avail_idx;
2089 __virtio16 ring_head;
2092 /* Check it isn't doing very strange things with descriptor numbers. */
2093 last_avail_idx = vq->last_avail_idx;
2095 if (vq->avail_idx == vq->last_avail_idx) {
2096 if (unlikely(vhost_get_avail(vq, avail_idx, &vq->avail->idx))) {
2097 vq_err(vq, "Failed to access avail idx at %p\n",
2101 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2103 if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) {
2104 vq_err(vq, "Guest moved used index from %u to %u",
2105 last_avail_idx, vq->avail_idx);
2109 /* If there's nothing new since last we looked, return
2112 if (vq->avail_idx == last_avail_idx)
2115 /* Only get avail ring entries after they have been
2121 /* Grab the next descriptor number they're advertising, and increment
2122 * the index we've seen. */
2123 if (unlikely(vhost_get_avail(vq, ring_head,
2124 &vq->avail->ring[last_avail_idx & (vq->num - 1)]))) {
2125 vq_err(vq, "Failed to read head: idx %d address %p\n",
2127 &vq->avail->ring[last_avail_idx % vq->num]);
2131 head = vhost16_to_cpu(vq, ring_head);
2133 /* If their number is silly, that's an error. */
2134 if (unlikely(head >= vq->num)) {
2135 vq_err(vq, "Guest says index %u > %u is available",
2140 /* When we start there are none of either input nor output. */
2141 *out_num = *in_num = 0;
2147 unsigned iov_count = *in_num + *out_num;
2148 if (unlikely(i >= vq->num)) {
2149 vq_err(vq, "Desc index is %u > %u, head = %u",
2153 if (unlikely(++found > vq->num)) {
2154 vq_err(vq, "Loop detected: last one at %u "
2155 "vq size %u head %u\n",
2159 ret = vhost_copy_from_user(vq, &desc, vq->desc + i,
2161 if (unlikely(ret)) {
2162 vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
2166 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT)) {
2167 ret = get_indirect(vq, iov, iov_size,
2169 log, log_num, &desc);
2170 if (unlikely(ret < 0)) {
2172 vq_err(vq, "Failure detected "
2173 "in indirect descriptor at idx %d\n", i);
2179 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
2180 access = VHOST_ACCESS_WO;
2182 access = VHOST_ACCESS_RO;
2183 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
2184 vhost32_to_cpu(vq, desc.len), iov + iov_count,
2185 iov_size - iov_count, access);
2186 if (unlikely(ret < 0)) {
2188 vq_err(vq, "Translation failure %d descriptor idx %d\n",
2192 if (access == VHOST_ACCESS_WO) {
2193 /* If this is an input descriptor,
2194 * increment that count. */
2196 if (unlikely(log)) {
2197 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
2198 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
2202 /* If it's an output descriptor, they're all supposed
2203 * to come before any input descriptors. */
2204 if (unlikely(*in_num)) {
2205 vq_err(vq, "Descriptor has out after in: "
2211 } while ((i = next_desc(vq, &desc)) != -1);
2213 /* On success, increment avail index. */
2214 vq->last_avail_idx++;
2216 /* Assume notifications from guest are disabled at this point,
2217 * if they aren't we would need to update avail_event index. */
2218 BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY));
2221 EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
2223 /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
2224 void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n)
2226 vq->last_avail_idx -= n;
2228 EXPORT_SYMBOL_GPL(vhost_discard_vq_desc);
2230 /* After we've used one of their buffers, we tell them about it. We'll then
2231 * want to notify the guest, using eventfd. */
2232 int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
2234 struct vring_used_elem heads = {
2235 cpu_to_vhost32(vq, head),
2236 cpu_to_vhost32(vq, len)
2239 return vhost_add_used_n(vq, &heads, 1);
2241 EXPORT_SYMBOL_GPL(vhost_add_used);
2243 static int __vhost_add_used_n(struct vhost_virtqueue *vq,
2244 struct vring_used_elem *heads,
2247 struct vring_used_elem __user *used;
2251 start = vq->last_used_idx & (vq->num - 1);
2252 used = vq->used->ring + start;
2254 if (vhost_put_user(vq, heads[0].id, &used->id)) {
2255 vq_err(vq, "Failed to write used id");
2258 if (vhost_put_user(vq, heads[0].len, &used->len)) {
2259 vq_err(vq, "Failed to write used len");
2262 } else if (vhost_copy_to_user(vq, used, heads, count * sizeof *used)) {
2263 vq_err(vq, "Failed to write used");
2266 if (unlikely(vq->log_used)) {
2267 /* Make sure data is seen before log. */
2269 /* Log used ring entry write. */
2270 log_used(vq, ((void __user *)used - (void __user *)vq->used),
2271 count * sizeof *used);
2273 old = vq->last_used_idx;
2274 new = (vq->last_used_idx += count);
2275 /* If the driver never bothers to signal in a very long while,
2276 * used index might wrap around. If that happens, invalidate
2277 * signalled_used index we stored. TODO: make sure driver
2278 * signals at least once in 2^16 and remove this. */
2279 if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old)))
2280 vq->signalled_used_valid = false;
2284 /* After we've used one of their buffers, we tell them about it. We'll then
2285 * want to notify the guest, using eventfd. */
2286 int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
2291 start = vq->last_used_idx & (vq->num - 1);
2292 n = vq->num - start;
2294 r = __vhost_add_used_n(vq, heads, n);
2300 r = __vhost_add_used_n(vq, heads, count);
2302 /* Make sure buffer is written before we update index. */
2304 if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx),
2306 vq_err(vq, "Failed to increment used idx");
2309 if (unlikely(vq->log_used)) {
2310 /* Make sure used idx is seen before log. */
2312 /* Log used index update. */
2313 log_used(vq, offsetof(struct vring_used, idx),
2314 sizeof vq->used->idx);
2316 eventfd_signal(vq->log_ctx, 1);
2320 EXPORT_SYMBOL_GPL(vhost_add_used_n);
2322 static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2327 /* Flush out used index updates. This is paired
2328 * with the barrier that the Guest executes when enabling
2332 if (vhost_has_feature(vq, VIRTIO_F_NOTIFY_ON_EMPTY) &&
2333 unlikely(vq->avail_idx == vq->last_avail_idx))
2336 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2338 if (vhost_get_avail(vq, flags, &vq->avail->flags)) {
2339 vq_err(vq, "Failed to get flags");
2342 return !(flags & cpu_to_vhost16(vq, VRING_AVAIL_F_NO_INTERRUPT));
2344 old = vq->signalled_used;
2345 v = vq->signalled_used_valid;
2346 new = vq->signalled_used = vq->last_used_idx;
2347 vq->signalled_used_valid = true;
2352 if (vhost_get_avail(vq, event, vhost_used_event(vq))) {
2353 vq_err(vq, "Failed to get used event idx");
2356 return vring_need_event(vhost16_to_cpu(vq, event), new, old);
2359 /* This actually signals the guest, using eventfd. */
2360 void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2362 /* Signal the Guest tell them we used something up. */
2363 if (vq->call_ctx && vhost_notify(dev, vq))
2364 eventfd_signal(vq->call_ctx, 1);
2366 EXPORT_SYMBOL_GPL(vhost_signal);
2368 /* And here's the combo meal deal. Supersize me! */
2369 void vhost_add_used_and_signal(struct vhost_dev *dev,
2370 struct vhost_virtqueue *vq,
2371 unsigned int head, int len)
2373 vhost_add_used(vq, head, len);
2374 vhost_signal(dev, vq);
2376 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal);
2378 /* multi-buffer version of vhost_add_used_and_signal */
2379 void vhost_add_used_and_signal_n(struct vhost_dev *dev,
2380 struct vhost_virtqueue *vq,
2381 struct vring_used_elem *heads, unsigned count)
2383 vhost_add_used_n(vq, heads, count);
2384 vhost_signal(dev, vq);
2386 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
2388 /* return true if we're sure that avaiable ring is empty */
2389 bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2391 __virtio16 avail_idx;
2394 if (vq->avail_idx != vq->last_avail_idx)
2397 r = vhost_get_avail(vq, avail_idx, &vq->avail->idx);
2400 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2402 return vq->avail_idx == vq->last_avail_idx;
2404 EXPORT_SYMBOL_GPL(vhost_vq_avail_empty);
2406 /* OK, now we need to know about added descriptors. */
2407 bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2409 __virtio16 avail_idx;
2412 if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
2414 vq->used_flags &= ~VRING_USED_F_NO_NOTIFY;
2415 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2416 r = vhost_update_used_flags(vq);
2418 vq_err(vq, "Failed to enable notification at %p: %d\n",
2419 &vq->used->flags, r);
2423 r = vhost_update_avail_event(vq, vq->avail_idx);
2425 vq_err(vq, "Failed to update avail event index at %p: %d\n",
2426 vhost_avail_event(vq), r);
2430 /* They could have slipped one in as we were doing that: make
2431 * sure it's written, then check again. */
2433 r = vhost_get_avail(vq, avail_idx, &vq->avail->idx);
2435 vq_err(vq, "Failed to check avail idx at %p: %d\n",
2436 &vq->avail->idx, r);
2440 return vhost16_to_cpu(vq, avail_idx) != vq->avail_idx;
2442 EXPORT_SYMBOL_GPL(vhost_enable_notify);
2444 /* We don't need to be notified again. */
2445 void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2449 if (vq->used_flags & VRING_USED_F_NO_NOTIFY)
2451 vq->used_flags |= VRING_USED_F_NO_NOTIFY;
2452 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2453 r = vhost_update_used_flags(vq);
2455 vq_err(vq, "Failed to enable notification at %p: %d\n",
2456 &vq->used->flags, r);
2459 EXPORT_SYMBOL_GPL(vhost_disable_notify);
2461 /* Create a new message. */
2462 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type)
2464 struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL);
2468 /* Make sure all padding within the structure is initialized. */
2469 memset(&node->msg, 0, sizeof node->msg);
2471 node->msg.type = type;
2474 EXPORT_SYMBOL_GPL(vhost_new_msg);
2476 void vhost_enqueue_msg(struct vhost_dev *dev, struct list_head *head,
2477 struct vhost_msg_node *node)
2479 spin_lock(&dev->iotlb_lock);
2480 list_add_tail(&node->node, head);
2481 spin_unlock(&dev->iotlb_lock);
2483 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
2485 EXPORT_SYMBOL_GPL(vhost_enqueue_msg);
2487 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
2488 struct list_head *head)
2490 struct vhost_msg_node *node = NULL;
2492 spin_lock(&dev->iotlb_lock);
2493 if (!list_empty(head)) {
2494 node = list_first_entry(head, struct vhost_msg_node,
2496 list_del(&node->node);
2498 spin_unlock(&dev->iotlb_lock);
2502 EXPORT_SYMBOL_GPL(vhost_dequeue_msg);
2505 static int __init vhost_init(void)
2510 static void __exit vhost_exit(void)
2514 module_init(vhost_init);
2515 module_exit(vhost_exit);
2517 MODULE_VERSION("0.0.1");
2518 MODULE_LICENSE("GPL v2");
2519 MODULE_AUTHOR("Michael S. Tsirkin");
2520 MODULE_DESCRIPTION("Host kernel accelerator for virtio");