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_disable_cross_endian(vq);
326 vhost_reset_is_le(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(dev->iov_limit, sizeof(*vq->log),
395 vq->heads = kmalloc_array(dev->iov_limit, 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 bool vhost_exceeds_weight(struct vhost_virtqueue *vq,
417 int pkts, int total_len)
419 struct vhost_dev *dev = vq->dev;
421 if ((dev->byte_weight && total_len >= dev->byte_weight) ||
422 pkts >= dev->weight) {
423 vhost_poll_queue(&vq->poll);
429 EXPORT_SYMBOL_GPL(vhost_exceeds_weight);
431 void vhost_dev_init(struct vhost_dev *dev,
432 struct vhost_virtqueue **vqs, int nvqs,
433 int iov_limit, int weight, int byte_weight)
435 struct vhost_virtqueue *vq;
440 mutex_init(&dev->mutex);
446 dev->iov_limit = iov_limit;
447 dev->weight = weight;
448 dev->byte_weight = byte_weight;
449 init_llist_head(&dev->work_list);
450 init_waitqueue_head(&dev->wait);
451 INIT_LIST_HEAD(&dev->read_list);
452 INIT_LIST_HEAD(&dev->pending_list);
453 spin_lock_init(&dev->iotlb_lock);
456 for (i = 0; i < dev->nvqs; ++i) {
462 mutex_init(&vq->mutex);
463 vhost_vq_reset(dev, vq);
465 vhost_poll_init(&vq->poll, vq->handle_kick,
469 EXPORT_SYMBOL_GPL(vhost_dev_init);
471 /* Caller should have device mutex */
472 long vhost_dev_check_owner(struct vhost_dev *dev)
474 /* Are you the owner? If not, I don't think you mean to do that */
475 return dev->mm == current->mm ? 0 : -EPERM;
477 EXPORT_SYMBOL_GPL(vhost_dev_check_owner);
479 struct vhost_attach_cgroups_struct {
480 struct vhost_work work;
481 struct task_struct *owner;
485 static void vhost_attach_cgroups_work(struct vhost_work *work)
487 struct vhost_attach_cgroups_struct *s;
489 s = container_of(work, struct vhost_attach_cgroups_struct, work);
490 s->ret = cgroup_attach_task_all(s->owner, current);
493 static int vhost_attach_cgroups(struct vhost_dev *dev)
495 struct vhost_attach_cgroups_struct attach;
497 attach.owner = current;
498 vhost_work_init(&attach.work, vhost_attach_cgroups_work);
499 vhost_work_queue(dev, &attach.work);
500 vhost_work_flush(dev, &attach.work);
504 /* Caller should have device mutex */
505 bool vhost_dev_has_owner(struct vhost_dev *dev)
509 EXPORT_SYMBOL_GPL(vhost_dev_has_owner);
511 /* Caller should have device mutex */
512 long vhost_dev_set_owner(struct vhost_dev *dev)
514 struct task_struct *worker;
517 /* Is there an owner already? */
518 if (vhost_dev_has_owner(dev)) {
523 /* No owner, become one */
524 dev->mm = get_task_mm(current);
525 worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid);
526 if (IS_ERR(worker)) {
527 err = PTR_ERR(worker);
531 dev->worker = worker;
532 wake_up_process(worker); /* avoid contributing to loadavg */
534 err = vhost_attach_cgroups(dev);
538 err = vhost_dev_alloc_iovecs(dev);
544 kthread_stop(worker);
553 EXPORT_SYMBOL_GPL(vhost_dev_set_owner);
555 struct vhost_umem *vhost_dev_reset_owner_prepare(void)
557 return kvzalloc(sizeof(struct vhost_umem), GFP_KERNEL);
559 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare);
561 /* Caller should have device mutex */
562 void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_umem *umem)
566 vhost_dev_cleanup(dev);
568 /* Restore memory to default empty mapping. */
569 INIT_LIST_HEAD(&umem->umem_list);
571 /* We don't need VQ locks below since vhost_dev_cleanup makes sure
572 * VQs aren't running.
574 for (i = 0; i < dev->nvqs; ++i)
575 dev->vqs[i]->umem = umem;
577 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner);
579 void vhost_dev_stop(struct vhost_dev *dev)
583 for (i = 0; i < dev->nvqs; ++i) {
584 if (dev->vqs[i]->kick && dev->vqs[i]->handle_kick) {
585 vhost_poll_stop(&dev->vqs[i]->poll);
586 vhost_poll_flush(&dev->vqs[i]->poll);
590 EXPORT_SYMBOL_GPL(vhost_dev_stop);
592 static void vhost_umem_free(struct vhost_umem *umem,
593 struct vhost_umem_node *node)
595 vhost_umem_interval_tree_remove(node, &umem->umem_tree);
596 list_del(&node->link);
601 static void vhost_umem_clean(struct vhost_umem *umem)
603 struct vhost_umem_node *node, *tmp;
608 list_for_each_entry_safe(node, tmp, &umem->umem_list, link)
609 vhost_umem_free(umem, node);
614 static void vhost_clear_msg(struct vhost_dev *dev)
616 struct vhost_msg_node *node, *n;
618 spin_lock(&dev->iotlb_lock);
620 list_for_each_entry_safe(node, n, &dev->read_list, node) {
621 list_del(&node->node);
625 list_for_each_entry_safe(node, n, &dev->pending_list, node) {
626 list_del(&node->node);
630 spin_unlock(&dev->iotlb_lock);
633 void vhost_dev_cleanup(struct vhost_dev *dev)
637 for (i = 0; i < dev->nvqs; ++i) {
638 if (dev->vqs[i]->error_ctx)
639 eventfd_ctx_put(dev->vqs[i]->error_ctx);
640 if (dev->vqs[i]->kick)
641 fput(dev->vqs[i]->kick);
642 if (dev->vqs[i]->call_ctx)
643 eventfd_ctx_put(dev->vqs[i]->call_ctx);
644 vhost_vq_reset(dev, dev->vqs[i]);
646 vhost_dev_free_iovecs(dev);
648 eventfd_ctx_put(dev->log_ctx);
650 /* No one will access memory at this point */
651 vhost_umem_clean(dev->umem);
653 vhost_umem_clean(dev->iotlb);
655 vhost_clear_msg(dev);
656 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
657 WARN_ON(!llist_empty(&dev->work_list));
659 kthread_stop(dev->worker);
666 EXPORT_SYMBOL_GPL(vhost_dev_cleanup);
668 static bool log_access_ok(void __user *log_base, u64 addr, unsigned long sz)
670 u64 a = addr / VHOST_PAGE_SIZE / 8;
672 /* Make sure 64 bit math will not overflow. */
673 if (a > ULONG_MAX - (unsigned long)log_base ||
674 a + (unsigned long)log_base > ULONG_MAX)
677 return access_ok(VERIFY_WRITE, log_base + a,
678 (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8);
681 /* Make sure 64 bit math will not overflow. */
682 static bool vhost_overflow(u64 uaddr, u64 size)
684 if (uaddr > ULONG_MAX || size > ULONG_MAX)
690 return uaddr > ULONG_MAX - size + 1;
693 /* Caller should have vq mutex and device mutex. */
694 static bool vq_memory_access_ok(void __user *log_base, struct vhost_umem *umem,
697 struct vhost_umem_node *node;
702 list_for_each_entry(node, &umem->umem_list, link) {
703 unsigned long a = node->userspace_addr;
705 if (vhost_overflow(node->userspace_addr, node->size))
709 if (!access_ok(VERIFY_WRITE, (void __user *)a,
712 else if (log_all && !log_access_ok(log_base,
720 static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq,
721 u64 addr, unsigned int size,
724 const struct vhost_umem_node *node = vq->meta_iotlb[type];
729 return (void *)(uintptr_t)(node->userspace_addr + addr - node->start);
732 /* Can we switch to this memory table? */
733 /* Caller should have device mutex but not vq mutex */
734 static bool memory_access_ok(struct vhost_dev *d, struct vhost_umem *umem,
739 for (i = 0; i < d->nvqs; ++i) {
743 mutex_lock(&d->vqs[i]->mutex);
744 log = log_all || vhost_has_feature(d->vqs[i], VHOST_F_LOG_ALL);
745 /* If ring is inactive, will check when it's enabled. */
746 if (d->vqs[i]->private_data)
747 ok = vq_memory_access_ok(d->vqs[i]->log_base,
751 mutex_unlock(&d->vqs[i]->mutex);
758 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
759 struct iovec iov[], int iov_size, int access);
761 static int vhost_copy_to_user(struct vhost_virtqueue *vq, void __user *to,
762 const void *from, unsigned size)
767 return __copy_to_user(to, from, size);
769 /* This function should be called after iotlb
770 * prefetch, which means we're sure that all vq
771 * could be access through iotlb. So -EAGAIN should
772 * not happen in this case.
775 void __user *uaddr = vhost_vq_meta_fetch(vq,
776 (u64)(uintptr_t)to, size,
780 return __copy_to_user(uaddr, from, size);
782 ret = translate_desc(vq, (u64)(uintptr_t)to, size, vq->iotlb_iov,
783 ARRAY_SIZE(vq->iotlb_iov),
787 iov_iter_init(&t, WRITE, vq->iotlb_iov, ret, size);
788 ret = copy_to_iter(from, size, &t);
796 static int vhost_copy_from_user(struct vhost_virtqueue *vq, void *to,
797 void __user *from, unsigned size)
802 return __copy_from_user(to, from, size);
804 /* This function should be called after iotlb
805 * prefetch, which means we're sure that vq
806 * could be access through iotlb. So -EAGAIN should
807 * not happen in this case.
809 void __user *uaddr = vhost_vq_meta_fetch(vq,
810 (u64)(uintptr_t)from, size,
815 return __copy_from_user(to, uaddr, size);
817 ret = translate_desc(vq, (u64)(uintptr_t)from, size, vq->iotlb_iov,
818 ARRAY_SIZE(vq->iotlb_iov),
821 vq_err(vq, "IOTLB translation failure: uaddr "
822 "%p size 0x%llx\n", from,
823 (unsigned long long) size);
826 iov_iter_init(&f, READ, vq->iotlb_iov, ret, size);
827 ret = copy_from_iter(to, size, &f);
836 static void __user *__vhost_get_user_slow(struct vhost_virtqueue *vq,
837 void __user *addr, unsigned int size,
842 ret = translate_desc(vq, (u64)(uintptr_t)addr, size, vq->iotlb_iov,
843 ARRAY_SIZE(vq->iotlb_iov),
846 vq_err(vq, "IOTLB translation failure: uaddr "
847 "%p size 0x%llx\n", addr,
848 (unsigned long long) size);
852 if (ret != 1 || vq->iotlb_iov[0].iov_len != size) {
853 vq_err(vq, "Non atomic userspace memory access: uaddr "
854 "%p size 0x%llx\n", addr,
855 (unsigned long long) size);
859 return vq->iotlb_iov[0].iov_base;
862 /* This function should be called after iotlb
863 * prefetch, which means we're sure that vq
864 * could be access through iotlb. So -EAGAIN should
865 * not happen in this case.
867 static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq,
868 void *addr, unsigned int size,
871 void __user *uaddr = vhost_vq_meta_fetch(vq,
872 (u64)(uintptr_t)addr, size, type);
876 return __vhost_get_user_slow(vq, addr, size, type);
879 #define vhost_put_user(vq, x, ptr) \
883 ret = __put_user(x, ptr); \
885 __typeof__(ptr) to = \
886 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
887 sizeof(*ptr), VHOST_ADDR_USED); \
889 ret = __put_user(x, to); \
896 #define vhost_get_user(vq, x, ptr, type) \
900 ret = __get_user(x, ptr); \
902 __typeof__(ptr) from = \
903 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
907 ret = __get_user(x, from); \
914 #define vhost_get_avail(vq, x, ptr) \
915 vhost_get_user(vq, x, ptr, VHOST_ADDR_AVAIL)
917 #define vhost_get_used(vq, x, ptr) \
918 vhost_get_user(vq, x, ptr, VHOST_ADDR_USED)
920 static void vhost_dev_lock_vqs(struct vhost_dev *d)
923 for (i = 0; i < d->nvqs; ++i)
924 mutex_lock_nested(&d->vqs[i]->mutex, i);
927 static void vhost_dev_unlock_vqs(struct vhost_dev *d)
930 for (i = 0; i < d->nvqs; ++i)
931 mutex_unlock(&d->vqs[i]->mutex);
934 static int vhost_new_umem_range(struct vhost_umem *umem,
935 u64 start, u64 size, u64 end,
936 u64 userspace_addr, int perm)
938 struct vhost_umem_node *tmp, *node;
943 node = kmalloc(sizeof(*node), GFP_ATOMIC);
947 if (umem->numem == max_iotlb_entries) {
948 tmp = list_first_entry(&umem->umem_list, typeof(*tmp), link);
949 vhost_umem_free(umem, tmp);
955 node->userspace_addr = userspace_addr;
957 INIT_LIST_HEAD(&node->link);
958 list_add_tail(&node->link, &umem->umem_list);
959 vhost_umem_interval_tree_insert(node, &umem->umem_tree);
965 static void vhost_del_umem_range(struct vhost_umem *umem,
968 struct vhost_umem_node *node;
970 while ((node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
972 vhost_umem_free(umem, node);
975 static void vhost_iotlb_notify_vq(struct vhost_dev *d,
976 struct vhost_iotlb_msg *msg)
978 struct vhost_msg_node *node, *n;
980 spin_lock(&d->iotlb_lock);
982 list_for_each_entry_safe(node, n, &d->pending_list, node) {
983 struct vhost_iotlb_msg *vq_msg = &node->msg.iotlb;
984 if (msg->iova <= vq_msg->iova &&
985 msg->iova + msg->size - 1 >= vq_msg->iova &&
986 vq_msg->type == VHOST_IOTLB_MISS) {
987 vhost_poll_queue(&node->vq->poll);
988 list_del(&node->node);
993 spin_unlock(&d->iotlb_lock);
996 static bool umem_access_ok(u64 uaddr, u64 size, int access)
998 unsigned long a = uaddr;
1000 /* Make sure 64 bit math will not overflow. */
1001 if (vhost_overflow(uaddr, size))
1004 if ((access & VHOST_ACCESS_RO) &&
1005 !access_ok(VERIFY_READ, (void __user *)a, size))
1007 if ((access & VHOST_ACCESS_WO) &&
1008 !access_ok(VERIFY_WRITE, (void __user *)a, size))
1013 static int vhost_process_iotlb_msg(struct vhost_dev *dev,
1014 struct vhost_iotlb_msg *msg)
1018 mutex_lock(&dev->mutex);
1019 vhost_dev_lock_vqs(dev);
1020 switch (msg->type) {
1021 case VHOST_IOTLB_UPDATE:
1026 if (!umem_access_ok(msg->uaddr, msg->size, msg->perm)) {
1030 vhost_vq_meta_reset(dev);
1031 if (vhost_new_umem_range(dev->iotlb, msg->iova, msg->size,
1032 msg->iova + msg->size - 1,
1033 msg->uaddr, msg->perm)) {
1037 vhost_iotlb_notify_vq(dev, msg);
1039 case VHOST_IOTLB_INVALIDATE:
1044 vhost_vq_meta_reset(dev);
1045 vhost_del_umem_range(dev->iotlb, msg->iova,
1046 msg->iova + msg->size - 1);
1053 vhost_dev_unlock_vqs(dev);
1054 mutex_unlock(&dev->mutex);
1058 ssize_t vhost_chr_write_iter(struct vhost_dev *dev,
1059 struct iov_iter *from)
1061 struct vhost_iotlb_msg msg;
1065 ret = copy_from_iter(&type, sizeof(type), from);
1066 if (ret != sizeof(type)) {
1072 case VHOST_IOTLB_MSG:
1073 /* There maybe a hole after type for V1 message type,
1076 offset = offsetof(struct vhost_msg, iotlb) - sizeof(int);
1078 case VHOST_IOTLB_MSG_V2:
1079 offset = sizeof(__u32);
1086 iov_iter_advance(from, offset);
1087 ret = copy_from_iter(&msg, sizeof(msg), from);
1088 if (ret != sizeof(msg)) {
1092 if (vhost_process_iotlb_msg(dev, &msg)) {
1097 ret = (type == VHOST_IOTLB_MSG) ? sizeof(struct vhost_msg) :
1098 sizeof(struct vhost_msg_v2);
1102 EXPORT_SYMBOL(vhost_chr_write_iter);
1104 __poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev,
1109 poll_wait(file, &dev->wait, wait);
1111 if (!list_empty(&dev->read_list))
1112 mask |= EPOLLIN | EPOLLRDNORM;
1116 EXPORT_SYMBOL(vhost_chr_poll);
1118 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to,
1122 struct vhost_msg_node *node;
1124 unsigned size = sizeof(struct vhost_msg);
1126 if (iov_iter_count(to) < size)
1131 prepare_to_wait(&dev->wait, &wait,
1132 TASK_INTERRUPTIBLE);
1134 node = vhost_dequeue_msg(dev, &dev->read_list);
1141 if (signal_pending(current)) {
1154 finish_wait(&dev->wait, &wait);
1157 struct vhost_iotlb_msg *msg;
1158 void *start = &node->msg;
1160 switch (node->msg.type) {
1161 case VHOST_IOTLB_MSG:
1162 size = sizeof(node->msg);
1163 msg = &node->msg.iotlb;
1165 case VHOST_IOTLB_MSG_V2:
1166 size = sizeof(node->msg_v2);
1167 msg = &node->msg_v2.iotlb;
1174 ret = copy_to_iter(start, size, to);
1175 if (ret != size || msg->type != VHOST_IOTLB_MISS) {
1179 vhost_enqueue_msg(dev, &dev->pending_list, node);
1184 EXPORT_SYMBOL_GPL(vhost_chr_read_iter);
1186 static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access)
1188 struct vhost_dev *dev = vq->dev;
1189 struct vhost_msg_node *node;
1190 struct vhost_iotlb_msg *msg;
1191 bool v2 = vhost_backend_has_feature(vq, VHOST_BACKEND_F_IOTLB_MSG_V2);
1193 node = vhost_new_msg(vq, v2 ? VHOST_IOTLB_MSG_V2 : VHOST_IOTLB_MSG);
1198 node->msg_v2.type = VHOST_IOTLB_MSG_V2;
1199 msg = &node->msg_v2.iotlb;
1201 msg = &node->msg.iotlb;
1204 msg->type = VHOST_IOTLB_MISS;
1208 vhost_enqueue_msg(dev, &dev->read_list, node);
1213 static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
1214 struct vring_desc __user *desc,
1215 struct vring_avail __user *avail,
1216 struct vring_used __user *used)
1219 size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
1221 return access_ok(VERIFY_READ, desc, num * sizeof *desc) &&
1222 access_ok(VERIFY_READ, avail,
1223 sizeof *avail + num * sizeof *avail->ring + s) &&
1224 access_ok(VERIFY_WRITE, used,
1225 sizeof *used + num * sizeof *used->ring + s);
1228 static void vhost_vq_meta_update(struct vhost_virtqueue *vq,
1229 const struct vhost_umem_node *node,
1232 int access = (type == VHOST_ADDR_USED) ?
1233 VHOST_ACCESS_WO : VHOST_ACCESS_RO;
1235 if (likely(node->perm & access))
1236 vq->meta_iotlb[type] = node;
1239 static bool iotlb_access_ok(struct vhost_virtqueue *vq,
1240 int access, u64 addr, u64 len, int type)
1242 const struct vhost_umem_node *node;
1243 struct vhost_umem *umem = vq->iotlb;
1244 u64 s = 0, size, orig_addr = addr, last = addr + len - 1;
1246 if (vhost_vq_meta_fetch(vq, addr, len, type))
1250 node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
1253 if (node == NULL || node->start > addr) {
1254 vhost_iotlb_miss(vq, addr, access);
1256 } else if (!(node->perm & access)) {
1257 /* Report the possible access violation by
1258 * request another translation from userspace.
1263 size = node->size - addr + node->start;
1265 if (orig_addr == addr && size >= len)
1266 vhost_vq_meta_update(vq, node, type);
1275 int vq_iotlb_prefetch(struct vhost_virtqueue *vq)
1277 size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
1278 unsigned int num = vq->num;
1283 return iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->desc,
1284 num * sizeof(*vq->desc), VHOST_ADDR_DESC) &&
1285 iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->avail,
1287 num * sizeof(*vq->avail->ring) + s,
1288 VHOST_ADDR_AVAIL) &&
1289 iotlb_access_ok(vq, VHOST_ACCESS_WO, (u64)(uintptr_t)vq->used,
1291 num * sizeof(*vq->used->ring) + s,
1294 EXPORT_SYMBOL_GPL(vq_iotlb_prefetch);
1296 /* Can we log writes? */
1297 /* Caller should have device mutex but not vq mutex */
1298 bool vhost_log_access_ok(struct vhost_dev *dev)
1300 return memory_access_ok(dev, dev->umem, 1);
1302 EXPORT_SYMBOL_GPL(vhost_log_access_ok);
1304 /* Verify access for write logging. */
1305 /* Caller should have vq mutex and device mutex */
1306 static bool vq_log_access_ok(struct vhost_virtqueue *vq,
1307 void __user *log_base)
1309 size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
1311 return vq_memory_access_ok(log_base, vq->umem,
1312 vhost_has_feature(vq, VHOST_F_LOG_ALL)) &&
1313 (!vq->log_used || log_access_ok(log_base, vq->log_addr,
1315 vq->num * sizeof *vq->used->ring + s));
1318 /* Can we start vq? */
1319 /* Caller should have vq mutex and device mutex */
1320 bool vhost_vq_access_ok(struct vhost_virtqueue *vq)
1322 if (!vq_log_access_ok(vq, vq->log_base))
1325 /* Access validation occurs at prefetch time with IOTLB */
1329 return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used);
1331 EXPORT_SYMBOL_GPL(vhost_vq_access_ok);
1333 static struct vhost_umem *vhost_umem_alloc(void)
1335 struct vhost_umem *umem = kvzalloc(sizeof(*umem), GFP_KERNEL);
1340 umem->umem_tree = RB_ROOT_CACHED;
1342 INIT_LIST_HEAD(&umem->umem_list);
1347 static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m)
1349 struct vhost_memory mem, *newmem;
1350 struct vhost_memory_region *region;
1351 struct vhost_umem *newumem, *oldumem;
1352 unsigned long size = offsetof(struct vhost_memory, regions);
1355 if (copy_from_user(&mem, m, size))
1359 if (mem.nregions > max_mem_regions)
1361 newmem = kvzalloc(struct_size(newmem, regions, mem.nregions),
1366 memcpy(newmem, &mem, size);
1367 if (copy_from_user(newmem->regions, m->regions,
1368 mem.nregions * sizeof *m->regions)) {
1373 newumem = vhost_umem_alloc();
1379 for (region = newmem->regions;
1380 region < newmem->regions + mem.nregions;
1382 if (vhost_new_umem_range(newumem,
1383 region->guest_phys_addr,
1384 region->memory_size,
1385 region->guest_phys_addr +
1386 region->memory_size - 1,
1387 region->userspace_addr,
1392 if (!memory_access_ok(d, newumem, 0))
1398 /* All memory accesses are done under some VQ mutex. */
1399 for (i = 0; i < d->nvqs; ++i) {
1400 mutex_lock(&d->vqs[i]->mutex);
1401 d->vqs[i]->umem = newumem;
1402 mutex_unlock(&d->vqs[i]->mutex);
1406 vhost_umem_clean(oldumem);
1410 vhost_umem_clean(newumem);
1415 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
1417 struct file *eventfp, *filep = NULL;
1418 bool pollstart = false, pollstop = false;
1419 struct eventfd_ctx *ctx = NULL;
1420 u32 __user *idxp = argp;
1421 struct vhost_virtqueue *vq;
1422 struct vhost_vring_state s;
1423 struct vhost_vring_file f;
1424 struct vhost_vring_addr a;
1428 r = get_user(idx, idxp);
1434 idx = array_index_nospec(idx, d->nvqs);
1437 mutex_lock(&vq->mutex);
1440 case VHOST_SET_VRING_NUM:
1441 /* Resizing ring with an active backend?
1442 * You don't want to do that. */
1443 if (vq->private_data) {
1447 if (copy_from_user(&s, argp, sizeof s)) {
1451 if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) {
1457 case VHOST_SET_VRING_BASE:
1458 /* Moving base with an active backend?
1459 * You don't want to do that. */
1460 if (vq->private_data) {
1464 if (copy_from_user(&s, argp, sizeof s)) {
1468 if (s.num > 0xffff) {
1472 vq->last_avail_idx = s.num;
1473 /* Forget the cached index value. */
1474 vq->avail_idx = vq->last_avail_idx;
1476 case VHOST_GET_VRING_BASE:
1478 s.num = vq->last_avail_idx;
1479 if (copy_to_user(argp, &s, sizeof s))
1482 case VHOST_SET_VRING_ADDR:
1483 if (copy_from_user(&a, argp, sizeof a)) {
1487 if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) {
1491 /* For 32bit, verify that the top 32bits of the user
1492 data are set to zero. */
1493 if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr ||
1494 (u64)(unsigned long)a.used_user_addr != a.used_user_addr ||
1495 (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) {
1500 /* Make sure it's safe to cast pointers to vring types. */
1501 BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE);
1502 BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE);
1503 if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) ||
1504 (a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) ||
1505 (a.log_guest_addr & (VRING_USED_ALIGN_SIZE - 1))) {
1510 /* We only verify access here if backend is configured.
1511 * If it is not, we don't as size might not have been setup.
1512 * We will verify when backend is configured. */
1513 if (vq->private_data) {
1514 if (!vq_access_ok(vq, vq->num,
1515 (void __user *)(unsigned long)a.desc_user_addr,
1516 (void __user *)(unsigned long)a.avail_user_addr,
1517 (void __user *)(unsigned long)a.used_user_addr)) {
1522 /* Also validate log access for used ring if enabled. */
1523 if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) &&
1524 !log_access_ok(vq->log_base, a.log_guest_addr,
1526 vq->num * sizeof *vq->used->ring)) {
1532 vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG));
1533 vq->desc = (void __user *)(unsigned long)a.desc_user_addr;
1534 vq->avail = (void __user *)(unsigned long)a.avail_user_addr;
1535 vq->log_addr = a.log_guest_addr;
1536 vq->used = (void __user *)(unsigned long)a.used_user_addr;
1538 case VHOST_SET_VRING_KICK:
1539 if (copy_from_user(&f, argp, sizeof f)) {
1543 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd);
1544 if (IS_ERR(eventfp)) {
1545 r = PTR_ERR(eventfp);
1548 if (eventfp != vq->kick) {
1549 pollstop = (filep = vq->kick) != NULL;
1550 pollstart = (vq->kick = eventfp) != NULL;
1554 case VHOST_SET_VRING_CALL:
1555 if (copy_from_user(&f, argp, sizeof f)) {
1559 ctx = f.fd == -1 ? NULL : eventfd_ctx_fdget(f.fd);
1564 swap(ctx, vq->call_ctx);
1566 case VHOST_SET_VRING_ERR:
1567 if (copy_from_user(&f, argp, sizeof f)) {
1571 ctx = f.fd == -1 ? NULL : eventfd_ctx_fdget(f.fd);
1576 swap(ctx, vq->error_ctx);
1578 case VHOST_SET_VRING_ENDIAN:
1579 r = vhost_set_vring_endian(vq, argp);
1581 case VHOST_GET_VRING_ENDIAN:
1582 r = vhost_get_vring_endian(vq, idx, argp);
1584 case VHOST_SET_VRING_BUSYLOOP_TIMEOUT:
1585 if (copy_from_user(&s, argp, sizeof(s))) {
1589 vq->busyloop_timeout = s.num;
1591 case VHOST_GET_VRING_BUSYLOOP_TIMEOUT:
1593 s.num = vq->busyloop_timeout;
1594 if (copy_to_user(argp, &s, sizeof(s)))
1601 if (pollstop && vq->handle_kick)
1602 vhost_poll_stop(&vq->poll);
1604 if (!IS_ERR_OR_NULL(ctx))
1605 eventfd_ctx_put(ctx);
1609 if (pollstart && vq->handle_kick)
1610 r = vhost_poll_start(&vq->poll, vq->kick);
1612 mutex_unlock(&vq->mutex);
1614 if (pollstop && vq->handle_kick)
1615 vhost_poll_flush(&vq->poll);
1618 EXPORT_SYMBOL_GPL(vhost_vring_ioctl);
1620 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled)
1622 struct vhost_umem *niotlb, *oiotlb;
1625 niotlb = vhost_umem_alloc();
1632 for (i = 0; i < d->nvqs; ++i) {
1633 struct vhost_virtqueue *vq = d->vqs[i];
1635 mutex_lock(&vq->mutex);
1637 __vhost_vq_meta_reset(vq);
1638 mutex_unlock(&vq->mutex);
1641 vhost_umem_clean(oiotlb);
1645 EXPORT_SYMBOL_GPL(vhost_init_device_iotlb);
1647 /* Caller must have device mutex */
1648 long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp)
1650 struct eventfd_ctx *ctx;
1655 /* If you are not the owner, you can become one */
1656 if (ioctl == VHOST_SET_OWNER) {
1657 r = vhost_dev_set_owner(d);
1661 /* You must be the owner to do anything else */
1662 r = vhost_dev_check_owner(d);
1667 case VHOST_SET_MEM_TABLE:
1668 r = vhost_set_memory(d, argp);
1670 case VHOST_SET_LOG_BASE:
1671 if (copy_from_user(&p, argp, sizeof p)) {
1675 if ((u64)(unsigned long)p != p) {
1679 for (i = 0; i < d->nvqs; ++i) {
1680 struct vhost_virtqueue *vq;
1681 void __user *base = (void __user *)(unsigned long)p;
1683 mutex_lock(&vq->mutex);
1684 /* If ring is inactive, will check when it's enabled. */
1685 if (vq->private_data && !vq_log_access_ok(vq, base))
1688 vq->log_base = base;
1689 mutex_unlock(&vq->mutex);
1692 case VHOST_SET_LOG_FD:
1693 r = get_user(fd, (int __user *)argp);
1696 ctx = fd == -1 ? NULL : eventfd_ctx_fdget(fd);
1701 swap(ctx, d->log_ctx);
1702 for (i = 0; i < d->nvqs; ++i) {
1703 mutex_lock(&d->vqs[i]->mutex);
1704 d->vqs[i]->log_ctx = d->log_ctx;
1705 mutex_unlock(&d->vqs[i]->mutex);
1708 eventfd_ctx_put(ctx);
1717 EXPORT_SYMBOL_GPL(vhost_dev_ioctl);
1719 /* TODO: This is really inefficient. We need something like get_user()
1720 * (instruction directly accesses the data, with an exception table entry
1721 * returning -EFAULT). See Documentation/x86/exception-tables.txt.
1723 static int set_bit_to_user(int nr, void __user *addr)
1725 unsigned long log = (unsigned long)addr;
1728 int bit = nr + (log % PAGE_SIZE) * 8;
1731 r = get_user_pages_fast(log, 1, 1, &page);
1735 base = kmap_atomic(page);
1737 kunmap_atomic(base);
1738 set_page_dirty_lock(page);
1743 static int log_write(void __user *log_base,
1744 u64 write_address, u64 write_length)
1746 u64 write_page = write_address / VHOST_PAGE_SIZE;
1751 write_length += write_address % VHOST_PAGE_SIZE;
1753 u64 base = (u64)(unsigned long)log_base;
1754 u64 log = base + write_page / 8;
1755 int bit = write_page % 8;
1756 if ((u64)(unsigned long)log != log)
1758 r = set_bit_to_user(bit, (void __user *)(unsigned long)log);
1761 if (write_length <= VHOST_PAGE_SIZE)
1763 write_length -= VHOST_PAGE_SIZE;
1769 static int log_write_hva(struct vhost_virtqueue *vq, u64 hva, u64 len)
1771 struct vhost_umem *umem = vq->umem;
1772 struct vhost_umem_node *u;
1773 u64 start, end, l, min;
1779 /* More than one GPAs can be mapped into a single HVA. So
1780 * iterate all possible umems here to be safe.
1782 list_for_each_entry(u, &umem->umem_list, link) {
1783 if (u->userspace_addr > hva - 1 + len ||
1784 u->userspace_addr - 1 + u->size < hva)
1786 start = max(u->userspace_addr, hva);
1787 end = min(u->userspace_addr - 1 + u->size,
1789 l = end - start + 1;
1790 r = log_write(vq->log_base,
1791 u->start + start - u->userspace_addr,
1809 static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len)
1811 struct iovec iov[64];
1815 return log_write(vq->log_base, vq->log_addr + used_offset, len);
1817 ret = translate_desc(vq, (uintptr_t)vq->used + used_offset,
1818 len, iov, 64, VHOST_ACCESS_WO);
1822 for (i = 0; i < ret; i++) {
1823 ret = log_write_hva(vq, (uintptr_t)iov[i].iov_base,
1832 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
1833 unsigned int log_num, u64 len, struct iovec *iov, int count)
1837 /* Make sure data written is seen before log. */
1841 for (i = 0; i < count; i++) {
1842 r = log_write_hva(vq, (uintptr_t)iov[i].iov_base,
1850 for (i = 0; i < log_num; ++i) {
1851 u64 l = min(log[i].len, len);
1852 r = log_write(vq->log_base, log[i].addr, l);
1858 eventfd_signal(vq->log_ctx, 1);
1862 /* Length written exceeds what we have stored. This is a bug. */
1866 EXPORT_SYMBOL_GPL(vhost_log_write);
1868 static int vhost_update_used_flags(struct vhost_virtqueue *vq)
1871 if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags),
1872 &vq->used->flags) < 0)
1874 if (unlikely(vq->log_used)) {
1875 /* Make sure the flag is seen before log. */
1877 /* Log used flag write. */
1878 used = &vq->used->flags;
1879 log_used(vq, (used - (void __user *)vq->used),
1880 sizeof vq->used->flags);
1882 eventfd_signal(vq->log_ctx, 1);
1887 static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
1889 if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx),
1890 vhost_avail_event(vq)))
1892 if (unlikely(vq->log_used)) {
1894 /* Make sure the event is seen before log. */
1896 /* Log avail event write */
1897 used = vhost_avail_event(vq);
1898 log_used(vq, (used - (void __user *)vq->used),
1899 sizeof *vhost_avail_event(vq));
1901 eventfd_signal(vq->log_ctx, 1);
1906 int vhost_vq_init_access(struct vhost_virtqueue *vq)
1908 __virtio16 last_used_idx;
1910 bool is_le = vq->is_le;
1912 if (!vq->private_data)
1915 vhost_init_is_le(vq);
1917 r = vhost_update_used_flags(vq);
1920 vq->signalled_used_valid = false;
1922 !access_ok(VERIFY_READ, &vq->used->idx, sizeof vq->used->idx)) {
1926 r = vhost_get_used(vq, last_used_idx, &vq->used->idx);
1928 vq_err(vq, "Can't access used idx at %p\n",
1932 vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx);
1939 EXPORT_SYMBOL_GPL(vhost_vq_init_access);
1941 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len,
1942 struct iovec iov[], int iov_size, int access)
1944 const struct vhost_umem_node *node;
1945 struct vhost_dev *dev = vq->dev;
1946 struct vhost_umem *umem = dev->iotlb ? dev->iotlb : dev->umem;
1951 while ((u64)len > s) {
1953 if (unlikely(ret >= iov_size)) {
1958 node = vhost_umem_interval_tree_iter_first(&umem->umem_tree,
1959 addr, addr + len - 1);
1960 if (node == NULL || node->start > addr) {
1961 if (umem != dev->iotlb) {
1967 } else if (!(node->perm & access)) {
1973 size = node->size - addr + node->start;
1974 _iov->iov_len = min((u64)len - s, size);
1975 _iov->iov_base = (void __user *)(unsigned long)
1976 (node->userspace_addr + addr - node->start);
1983 vhost_iotlb_miss(vq, addr, access);
1987 /* Each buffer in the virtqueues is actually a chain of descriptors. This
1988 * function returns the next descriptor in the chain,
1989 * or -1U if we're at the end. */
1990 static unsigned next_desc(struct vhost_virtqueue *vq, struct vring_desc *desc)
1994 /* If this descriptor says it doesn't chain, we're done. */
1995 if (!(desc->flags & cpu_to_vhost16(vq, VRING_DESC_F_NEXT)))
1998 /* Check they're not leading us off end of descriptors. */
1999 next = vhost16_to_cpu(vq, READ_ONCE(desc->next));
2003 static int get_indirect(struct vhost_virtqueue *vq,
2004 struct iovec iov[], unsigned int iov_size,
2005 unsigned int *out_num, unsigned int *in_num,
2006 struct vhost_log *log, unsigned int *log_num,
2007 struct vring_desc *indirect)
2009 struct vring_desc desc;
2010 unsigned int i = 0, count, found = 0;
2011 u32 len = vhost32_to_cpu(vq, indirect->len);
2012 struct iov_iter from;
2016 if (unlikely(len % sizeof desc)) {
2017 vq_err(vq, "Invalid length in indirect descriptor: "
2018 "len 0x%llx not multiple of 0x%zx\n",
2019 (unsigned long long)len,
2024 ret = translate_desc(vq, vhost64_to_cpu(vq, indirect->addr), len, vq->indirect,
2025 UIO_MAXIOV, VHOST_ACCESS_RO);
2026 if (unlikely(ret < 0)) {
2028 vq_err(vq, "Translation failure %d in indirect.\n", ret);
2031 iov_iter_init(&from, READ, vq->indirect, ret, len);
2033 /* We will use the result as an address to read from, so most
2034 * architectures only need a compiler barrier here. */
2035 read_barrier_depends();
2037 count = len / sizeof desc;
2038 /* Buffers are chained via a 16 bit next field, so
2039 * we can have at most 2^16 of these. */
2040 if (unlikely(count > USHRT_MAX + 1)) {
2041 vq_err(vq, "Indirect buffer length too big: %d\n",
2047 unsigned iov_count = *in_num + *out_num;
2048 if (unlikely(++found > count)) {
2049 vq_err(vq, "Loop detected: last one at %u "
2050 "indirect size %u\n",
2054 if (unlikely(!copy_from_iter_full(&desc, sizeof(desc), &from))) {
2055 vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n",
2056 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
2059 if (unlikely(desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT))) {
2060 vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n",
2061 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc);
2065 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
2066 access = VHOST_ACCESS_WO;
2068 access = VHOST_ACCESS_RO;
2070 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
2071 vhost32_to_cpu(vq, desc.len), iov + iov_count,
2072 iov_size - iov_count, access);
2073 if (unlikely(ret < 0)) {
2075 vq_err(vq, "Translation failure %d indirect idx %d\n",
2079 /* If this is an input descriptor, increment that count. */
2080 if (access == VHOST_ACCESS_WO) {
2082 if (unlikely(log && ret)) {
2083 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
2084 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
2088 /* If it's an output descriptor, they're all supposed
2089 * to come before any input descriptors. */
2090 if (unlikely(*in_num)) {
2091 vq_err(vq, "Indirect descriptor "
2092 "has out after in: idx %d\n", i);
2097 } while ((i = next_desc(vq, &desc)) != -1);
2101 /* This looks in the virtqueue and for the first available buffer, and converts
2102 * it to an iovec for convenient access. Since descriptors consist of some
2103 * number of output then some number of input descriptors, it's actually two
2104 * iovecs, but we pack them into one and note how many of each there were.
2106 * This function returns the descriptor number found, or vq->num (which is
2107 * never a valid descriptor number) if none was found. A negative code is
2108 * returned on error. */
2109 int vhost_get_vq_desc(struct vhost_virtqueue *vq,
2110 struct iovec iov[], unsigned int iov_size,
2111 unsigned int *out_num, unsigned int *in_num,
2112 struct vhost_log *log, unsigned int *log_num)
2114 struct vring_desc desc;
2115 unsigned int i, head, found = 0;
2117 __virtio16 avail_idx;
2118 __virtio16 ring_head;
2121 /* Check it isn't doing very strange things with descriptor numbers. */
2122 last_avail_idx = vq->last_avail_idx;
2124 if (vq->avail_idx == vq->last_avail_idx) {
2125 if (unlikely(vhost_get_avail(vq, avail_idx, &vq->avail->idx))) {
2126 vq_err(vq, "Failed to access avail idx at %p\n",
2130 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2132 if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) {
2133 vq_err(vq, "Guest moved used index from %u to %u",
2134 last_avail_idx, vq->avail_idx);
2138 /* If there's nothing new since last we looked, return
2141 if (vq->avail_idx == last_avail_idx)
2144 /* Only get avail ring entries after they have been
2150 /* Grab the next descriptor number they're advertising, and increment
2151 * the index we've seen. */
2152 if (unlikely(vhost_get_avail(vq, ring_head,
2153 &vq->avail->ring[last_avail_idx & (vq->num - 1)]))) {
2154 vq_err(vq, "Failed to read head: idx %d address %p\n",
2156 &vq->avail->ring[last_avail_idx % vq->num]);
2160 head = vhost16_to_cpu(vq, ring_head);
2162 /* If their number is silly, that's an error. */
2163 if (unlikely(head >= vq->num)) {
2164 vq_err(vq, "Guest says index %u > %u is available",
2169 /* When we start there are none of either input nor output. */
2170 *out_num = *in_num = 0;
2176 unsigned iov_count = *in_num + *out_num;
2177 if (unlikely(i >= vq->num)) {
2178 vq_err(vq, "Desc index is %u > %u, head = %u",
2182 if (unlikely(++found > vq->num)) {
2183 vq_err(vq, "Loop detected: last one at %u "
2184 "vq size %u head %u\n",
2188 ret = vhost_copy_from_user(vq, &desc, vq->desc + i,
2190 if (unlikely(ret)) {
2191 vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
2195 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT)) {
2196 ret = get_indirect(vq, iov, iov_size,
2198 log, log_num, &desc);
2199 if (unlikely(ret < 0)) {
2201 vq_err(vq, "Failure detected "
2202 "in indirect descriptor at idx %d\n", i);
2208 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
2209 access = VHOST_ACCESS_WO;
2211 access = VHOST_ACCESS_RO;
2212 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
2213 vhost32_to_cpu(vq, desc.len), iov + iov_count,
2214 iov_size - iov_count, access);
2215 if (unlikely(ret < 0)) {
2217 vq_err(vq, "Translation failure %d descriptor idx %d\n",
2221 if (access == VHOST_ACCESS_WO) {
2222 /* If this is an input descriptor,
2223 * increment that count. */
2225 if (unlikely(log && ret)) {
2226 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr);
2227 log[*log_num].len = vhost32_to_cpu(vq, desc.len);
2231 /* If it's an output descriptor, they're all supposed
2232 * to come before any input descriptors. */
2233 if (unlikely(*in_num)) {
2234 vq_err(vq, "Descriptor has out after in: "
2240 } while ((i = next_desc(vq, &desc)) != -1);
2242 /* On success, increment avail index. */
2243 vq->last_avail_idx++;
2245 /* Assume notifications from guest are disabled at this point,
2246 * if they aren't we would need to update avail_event index. */
2247 BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY));
2250 EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
2252 /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
2253 void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n)
2255 vq->last_avail_idx -= n;
2257 EXPORT_SYMBOL_GPL(vhost_discard_vq_desc);
2259 /* After we've used one of their buffers, we tell them about it. We'll then
2260 * want to notify the guest, using eventfd. */
2261 int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
2263 struct vring_used_elem heads = {
2264 cpu_to_vhost32(vq, head),
2265 cpu_to_vhost32(vq, len)
2268 return vhost_add_used_n(vq, &heads, 1);
2270 EXPORT_SYMBOL_GPL(vhost_add_used);
2272 static int __vhost_add_used_n(struct vhost_virtqueue *vq,
2273 struct vring_used_elem *heads,
2276 struct vring_used_elem __user *used;
2280 start = vq->last_used_idx & (vq->num - 1);
2281 used = vq->used->ring + start;
2283 if (vhost_put_user(vq, heads[0].id, &used->id)) {
2284 vq_err(vq, "Failed to write used id");
2287 if (vhost_put_user(vq, heads[0].len, &used->len)) {
2288 vq_err(vq, "Failed to write used len");
2291 } else if (vhost_copy_to_user(vq, used, heads, count * sizeof *used)) {
2292 vq_err(vq, "Failed to write used");
2295 if (unlikely(vq->log_used)) {
2296 /* Make sure data is seen before log. */
2298 /* Log used ring entry write. */
2299 log_used(vq, ((void __user *)used - (void __user *)vq->used),
2300 count * sizeof *used);
2302 old = vq->last_used_idx;
2303 new = (vq->last_used_idx += count);
2304 /* If the driver never bothers to signal in a very long while,
2305 * used index might wrap around. If that happens, invalidate
2306 * signalled_used index we stored. TODO: make sure driver
2307 * signals at least once in 2^16 and remove this. */
2308 if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old)))
2309 vq->signalled_used_valid = false;
2313 /* After we've used one of their buffers, we tell them about it. We'll then
2314 * want to notify the guest, using eventfd. */
2315 int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
2320 start = vq->last_used_idx & (vq->num - 1);
2321 n = vq->num - start;
2323 r = __vhost_add_used_n(vq, heads, n);
2329 r = __vhost_add_used_n(vq, heads, count);
2331 /* Make sure buffer is written before we update index. */
2333 if (vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx),
2335 vq_err(vq, "Failed to increment used idx");
2338 if (unlikely(vq->log_used)) {
2339 /* Make sure used idx is seen before log. */
2341 /* Log used index update. */
2342 log_used(vq, offsetof(struct vring_used, idx),
2343 sizeof vq->used->idx);
2345 eventfd_signal(vq->log_ctx, 1);
2349 EXPORT_SYMBOL_GPL(vhost_add_used_n);
2351 static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2356 /* Flush out used index updates. This is paired
2357 * with the barrier that the Guest executes when enabling
2361 if (vhost_has_feature(vq, VIRTIO_F_NOTIFY_ON_EMPTY) &&
2362 unlikely(vq->avail_idx == vq->last_avail_idx))
2365 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2367 if (vhost_get_avail(vq, flags, &vq->avail->flags)) {
2368 vq_err(vq, "Failed to get flags");
2371 return !(flags & cpu_to_vhost16(vq, VRING_AVAIL_F_NO_INTERRUPT));
2373 old = vq->signalled_used;
2374 v = vq->signalled_used_valid;
2375 new = vq->signalled_used = vq->last_used_idx;
2376 vq->signalled_used_valid = true;
2381 if (vhost_get_avail(vq, event, vhost_used_event(vq))) {
2382 vq_err(vq, "Failed to get used event idx");
2385 return vring_need_event(vhost16_to_cpu(vq, event), new, old);
2388 /* This actually signals the guest, using eventfd. */
2389 void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2391 /* Signal the Guest tell them we used something up. */
2392 if (vq->call_ctx && vhost_notify(dev, vq))
2393 eventfd_signal(vq->call_ctx, 1);
2395 EXPORT_SYMBOL_GPL(vhost_signal);
2397 /* And here's the combo meal deal. Supersize me! */
2398 void vhost_add_used_and_signal(struct vhost_dev *dev,
2399 struct vhost_virtqueue *vq,
2400 unsigned int head, int len)
2402 vhost_add_used(vq, head, len);
2403 vhost_signal(dev, vq);
2405 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal);
2407 /* multi-buffer version of vhost_add_used_and_signal */
2408 void vhost_add_used_and_signal_n(struct vhost_dev *dev,
2409 struct vhost_virtqueue *vq,
2410 struct vring_used_elem *heads, unsigned count)
2412 vhost_add_used_n(vq, heads, count);
2413 vhost_signal(dev, vq);
2415 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
2417 /* return true if we're sure that avaiable ring is empty */
2418 bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2420 __virtio16 avail_idx;
2423 if (vq->avail_idx != vq->last_avail_idx)
2426 r = vhost_get_avail(vq, avail_idx, &vq->avail->idx);
2429 vq->avail_idx = vhost16_to_cpu(vq, avail_idx);
2431 return vq->avail_idx == vq->last_avail_idx;
2433 EXPORT_SYMBOL_GPL(vhost_vq_avail_empty);
2435 /* OK, now we need to know about added descriptors. */
2436 bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2438 __virtio16 avail_idx;
2441 if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY))
2443 vq->used_flags &= ~VRING_USED_F_NO_NOTIFY;
2444 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2445 r = vhost_update_used_flags(vq);
2447 vq_err(vq, "Failed to enable notification at %p: %d\n",
2448 &vq->used->flags, r);
2452 r = vhost_update_avail_event(vq, vq->avail_idx);
2454 vq_err(vq, "Failed to update avail event index at %p: %d\n",
2455 vhost_avail_event(vq), r);
2459 /* They could have slipped one in as we were doing that: make
2460 * sure it's written, then check again. */
2462 r = vhost_get_avail(vq, avail_idx, &vq->avail->idx);
2464 vq_err(vq, "Failed to check avail idx at %p: %d\n",
2465 &vq->avail->idx, r);
2469 return vhost16_to_cpu(vq, avail_idx) != vq->avail_idx;
2471 EXPORT_SYMBOL_GPL(vhost_enable_notify);
2473 /* We don't need to be notified again. */
2474 void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
2478 if (vq->used_flags & VRING_USED_F_NO_NOTIFY)
2480 vq->used_flags |= VRING_USED_F_NO_NOTIFY;
2481 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) {
2482 r = vhost_update_used_flags(vq);
2484 vq_err(vq, "Failed to enable notification at %p: %d\n",
2485 &vq->used->flags, r);
2488 EXPORT_SYMBOL_GPL(vhost_disable_notify);
2490 /* Create a new message. */
2491 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type)
2493 struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL);
2497 /* Make sure all padding within the structure is initialized. */
2498 memset(&node->msg, 0, sizeof node->msg);
2500 node->msg.type = type;
2503 EXPORT_SYMBOL_GPL(vhost_new_msg);
2505 void vhost_enqueue_msg(struct vhost_dev *dev, struct list_head *head,
2506 struct vhost_msg_node *node)
2508 spin_lock(&dev->iotlb_lock);
2509 list_add_tail(&node->node, head);
2510 spin_unlock(&dev->iotlb_lock);
2512 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM);
2514 EXPORT_SYMBOL_GPL(vhost_enqueue_msg);
2516 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev,
2517 struct list_head *head)
2519 struct vhost_msg_node *node = NULL;
2521 spin_lock(&dev->iotlb_lock);
2522 if (!list_empty(head)) {
2523 node = list_first_entry(head, struct vhost_msg_node,
2525 list_del(&node->node);
2527 spin_unlock(&dev->iotlb_lock);
2531 EXPORT_SYMBOL_GPL(vhost_dequeue_msg);
2534 static int __init vhost_init(void)
2539 static void __exit vhost_exit(void)
2543 module_init(vhost_init);
2544 module_exit(vhost_exit);
2546 MODULE_VERSION("0.0.1");
2547 MODULE_LICENSE("GPL v2");
2548 MODULE_AUTHOR("Michael S. Tsirkin");
2549 MODULE_DESCRIPTION("Host kernel accelerator for virtio");