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/interval_tree_generic.h>
34 static ushort max_mem_regions
= 64;
35 module_param(max_mem_regions
, ushort
, 0444);
36 MODULE_PARM_DESC(max_mem_regions
,
37 "Maximum number of memory regions in memory map. (default: 64)");
38 static int max_iotlb_entries
= 2048;
39 module_param(max_iotlb_entries
, int, 0444);
40 MODULE_PARM_DESC(max_iotlb_entries
,
41 "Maximum number of iotlb entries. (default: 2048)");
44 VHOST_MEMORY_F_LOG
= 0x1,
47 #define vhost_used_event(vq) ((__virtio16 __user *)&vq->avail->ring[vq->num])
48 #define vhost_avail_event(vq) ((__virtio16 __user *)&vq->used->ring[vq->num])
50 INTERVAL_TREE_DEFINE(struct vhost_umem_node
,
51 rb
, __u64
, __subtree_last
,
52 START
, LAST
, static inline, vhost_umem_interval_tree
);
54 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
55 static void vhost_disable_cross_endian(struct vhost_virtqueue
*vq
)
57 vq
->user_be
= !virtio_legacy_is_little_endian();
60 static void vhost_enable_cross_endian_big(struct vhost_virtqueue
*vq
)
65 static void vhost_enable_cross_endian_little(struct vhost_virtqueue
*vq
)
70 static long vhost_set_vring_endian(struct vhost_virtqueue
*vq
, int __user
*argp
)
72 struct vhost_vring_state s
;
77 if (copy_from_user(&s
, argp
, sizeof(s
)))
80 if (s
.num
!= VHOST_VRING_LITTLE_ENDIAN
&&
81 s
.num
!= VHOST_VRING_BIG_ENDIAN
)
84 if (s
.num
== VHOST_VRING_BIG_ENDIAN
)
85 vhost_enable_cross_endian_big(vq
);
87 vhost_enable_cross_endian_little(vq
);
92 static long vhost_get_vring_endian(struct vhost_virtqueue
*vq
, u32 idx
,
95 struct vhost_vring_state s
= {
100 if (copy_to_user(argp
, &s
, sizeof(s
)))
106 static void vhost_init_is_le(struct vhost_virtqueue
*vq
)
108 /* Note for legacy virtio: user_be is initialized at reset time
109 * according to the host endianness. If userspace does not set an
110 * explicit endianness, the default behavior is native endian, as
111 * expected by legacy virtio.
113 vq
->is_le
= vhost_has_feature(vq
, VIRTIO_F_VERSION_1
) || !vq
->user_be
;
116 static void vhost_disable_cross_endian(struct vhost_virtqueue
*vq
)
120 static long vhost_set_vring_endian(struct vhost_virtqueue
*vq
, int __user
*argp
)
125 static long vhost_get_vring_endian(struct vhost_virtqueue
*vq
, u32 idx
,
131 static void vhost_init_is_le(struct vhost_virtqueue
*vq
)
133 vq
->is_le
= vhost_has_feature(vq
, VIRTIO_F_VERSION_1
)
134 || virtio_legacy_is_little_endian();
136 #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
138 static void vhost_reset_is_le(struct vhost_virtqueue
*vq
)
140 vhost_init_is_le(vq
);
143 struct vhost_flush_struct
{
144 struct vhost_work work
;
145 struct completion wait_event
;
148 static void vhost_flush_work(struct vhost_work
*work
)
150 struct vhost_flush_struct
*s
;
152 s
= container_of(work
, struct vhost_flush_struct
, work
);
153 complete(&s
->wait_event
);
156 static void vhost_poll_func(struct file
*file
, wait_queue_head_t
*wqh
,
159 struct vhost_poll
*poll
;
161 poll
= container_of(pt
, struct vhost_poll
, table
);
163 add_wait_queue(wqh
, &poll
->wait
);
166 static int vhost_poll_wakeup(wait_queue_t
*wait
, unsigned mode
, int sync
,
169 struct vhost_poll
*poll
= container_of(wait
, struct vhost_poll
, wait
);
171 if (!((unsigned long)key
& poll
->mask
))
174 vhost_poll_queue(poll
);
178 void vhost_work_init(struct vhost_work
*work
, vhost_work_fn_t fn
)
180 clear_bit(VHOST_WORK_QUEUED
, &work
->flags
);
182 init_waitqueue_head(&work
->done
);
184 EXPORT_SYMBOL_GPL(vhost_work_init
);
186 /* Init poll structure */
187 void vhost_poll_init(struct vhost_poll
*poll
, vhost_work_fn_t fn
,
188 unsigned long mask
, struct vhost_dev
*dev
)
190 init_waitqueue_func_entry(&poll
->wait
, vhost_poll_wakeup
);
191 init_poll_funcptr(&poll
->table
, vhost_poll_func
);
196 vhost_work_init(&poll
->work
, fn
);
198 EXPORT_SYMBOL_GPL(vhost_poll_init
);
200 /* Start polling a file. We add ourselves to file's wait queue. The caller must
201 * keep a reference to a file until after vhost_poll_stop is called. */
202 int vhost_poll_start(struct vhost_poll
*poll
, struct file
*file
)
210 mask
= file
->f_op
->poll(file
, &poll
->table
);
212 vhost_poll_wakeup(&poll
->wait
, 0, 0, (void *)mask
);
213 if (mask
& POLLERR
) {
215 remove_wait_queue(poll
->wqh
, &poll
->wait
);
221 EXPORT_SYMBOL_GPL(vhost_poll_start
);
223 /* Stop polling a file. After this function returns, it becomes safe to drop the
224 * file reference. You must also flush afterwards. */
225 void vhost_poll_stop(struct vhost_poll
*poll
)
228 remove_wait_queue(poll
->wqh
, &poll
->wait
);
232 EXPORT_SYMBOL_GPL(vhost_poll_stop
);
234 void vhost_work_flush(struct vhost_dev
*dev
, struct vhost_work
*work
)
236 struct vhost_flush_struct flush
;
239 init_completion(&flush
.wait_event
);
240 vhost_work_init(&flush
.work
, vhost_flush_work
);
242 vhost_work_queue(dev
, &flush
.work
);
243 wait_for_completion(&flush
.wait_event
);
246 EXPORT_SYMBOL_GPL(vhost_work_flush
);
248 /* Flush any work that has been scheduled. When calling this, don't hold any
249 * locks that are also used by the callback. */
250 void vhost_poll_flush(struct vhost_poll
*poll
)
252 vhost_work_flush(poll
->dev
, &poll
->work
);
254 EXPORT_SYMBOL_GPL(vhost_poll_flush
);
256 void vhost_work_queue(struct vhost_dev
*dev
, struct vhost_work
*work
)
261 if (!test_and_set_bit(VHOST_WORK_QUEUED
, &work
->flags
)) {
262 /* We can only add the work to the list after we're
263 * sure it was not in the list.
264 * test_and_set_bit() implies a memory barrier.
266 llist_add(&work
->node
, &dev
->work_list
);
267 wake_up_process(dev
->worker
);
270 EXPORT_SYMBOL_GPL(vhost_work_queue
);
272 /* A lockless hint for busy polling code to exit the loop */
273 bool vhost_has_work(struct vhost_dev
*dev
)
275 return !llist_empty(&dev
->work_list
);
277 EXPORT_SYMBOL_GPL(vhost_has_work
);
279 void vhost_poll_queue(struct vhost_poll
*poll
)
281 vhost_work_queue(poll
->dev
, &poll
->work
);
283 EXPORT_SYMBOL_GPL(vhost_poll_queue
);
285 static void __vhost_vq_meta_reset(struct vhost_virtqueue
*vq
)
289 for (j
= 0; j
< VHOST_NUM_ADDRS
; j
++)
290 vq
->meta_iotlb
[j
] = NULL
;
293 static void vhost_vq_meta_reset(struct vhost_dev
*d
)
297 for (i
= 0; i
< d
->nvqs
; ++i
)
298 __vhost_vq_meta_reset(d
->vqs
[i
]);
301 static void vhost_vq_reset(struct vhost_dev
*dev
,
302 struct vhost_virtqueue
*vq
)
308 vq
->last_avail_idx
= 0;
309 vq
->last_used_event
= 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;
320 vq
->error_ctx
= NULL
;
326 vhost_reset_is_le(vq
);
327 vhost_disable_cross_endian(vq
);
328 vq
->busyloop_timeout
= 0;
331 __vhost_vq_meta_reset(vq
);
334 static int vhost_worker(void *data
)
336 struct vhost_dev
*dev
= data
;
337 struct vhost_work
*work
, *work_next
;
338 struct llist_node
*node
;
339 mm_segment_t oldfs
= get_fs();
345 /* mb paired w/ kthread_stop */
346 set_current_state(TASK_INTERRUPTIBLE
);
348 if (kthread_should_stop()) {
349 __set_current_state(TASK_RUNNING
);
353 node
= llist_del_all(&dev
->work_list
);
357 node
= llist_reverse_order(node
);
358 /* make sure flag is seen after deletion */
360 llist_for_each_entry_safe(work
, work_next
, node
, node
) {
361 clear_bit(VHOST_WORK_QUEUED
, &work
->flags
);
362 __set_current_state(TASK_RUNNING
);
373 static void vhost_vq_free_iovecs(struct vhost_virtqueue
*vq
)
383 /* Helper to allocate iovec buffers for all vqs. */
384 static long vhost_dev_alloc_iovecs(struct vhost_dev
*dev
)
386 struct vhost_virtqueue
*vq
;
389 for (i
= 0; i
< dev
->nvqs
; ++i
) {
391 vq
->indirect
= kmalloc(sizeof *vq
->indirect
* UIO_MAXIOV
,
393 vq
->log
= kmalloc(sizeof *vq
->log
* UIO_MAXIOV
, GFP_KERNEL
);
394 vq
->heads
= kmalloc(sizeof *vq
->heads
* UIO_MAXIOV
, GFP_KERNEL
);
395 if (!vq
->indirect
|| !vq
->log
|| !vq
->heads
)
402 vhost_vq_free_iovecs(dev
->vqs
[i
]);
406 static void vhost_dev_free_iovecs(struct vhost_dev
*dev
)
410 for (i
= 0; i
< dev
->nvqs
; ++i
)
411 vhost_vq_free_iovecs(dev
->vqs
[i
]);
414 void vhost_dev_init(struct vhost_dev
*dev
,
415 struct vhost_virtqueue
**vqs
, int nvqs
)
417 struct vhost_virtqueue
*vq
;
422 mutex_init(&dev
->mutex
);
424 dev
->log_file
= NULL
;
429 init_llist_head(&dev
->work_list
);
430 init_waitqueue_head(&dev
->wait
);
431 INIT_LIST_HEAD(&dev
->read_list
);
432 INIT_LIST_HEAD(&dev
->pending_list
);
433 spin_lock_init(&dev
->iotlb_lock
);
436 for (i
= 0; i
< dev
->nvqs
; ++i
) {
442 mutex_init(&vq
->mutex
);
443 vhost_vq_reset(dev
, vq
);
445 vhost_poll_init(&vq
->poll
, vq
->handle_kick
,
449 EXPORT_SYMBOL_GPL(vhost_dev_init
);
451 /* Caller should have device mutex */
452 long vhost_dev_check_owner(struct vhost_dev
*dev
)
454 /* Are you the owner? If not, I don't think you mean to do that */
455 return dev
->mm
== current
->mm
? 0 : -EPERM
;
457 EXPORT_SYMBOL_GPL(vhost_dev_check_owner
);
459 struct vhost_attach_cgroups_struct
{
460 struct vhost_work work
;
461 struct task_struct
*owner
;
465 static void vhost_attach_cgroups_work(struct vhost_work
*work
)
467 struct vhost_attach_cgroups_struct
*s
;
469 s
= container_of(work
, struct vhost_attach_cgroups_struct
, work
);
470 s
->ret
= cgroup_attach_task_all(s
->owner
, current
);
473 static int vhost_attach_cgroups(struct vhost_dev
*dev
)
475 struct vhost_attach_cgroups_struct attach
;
477 attach
.owner
= current
;
478 vhost_work_init(&attach
.work
, vhost_attach_cgroups_work
);
479 vhost_work_queue(dev
, &attach
.work
);
480 vhost_work_flush(dev
, &attach
.work
);
484 /* Caller should have device mutex */
485 bool vhost_dev_has_owner(struct vhost_dev
*dev
)
489 EXPORT_SYMBOL_GPL(vhost_dev_has_owner
);
491 /* Caller should have device mutex */
492 long vhost_dev_set_owner(struct vhost_dev
*dev
)
494 struct task_struct
*worker
;
497 /* Is there an owner already? */
498 if (vhost_dev_has_owner(dev
)) {
503 /* No owner, become one */
504 dev
->mm
= get_task_mm(current
);
505 worker
= kthread_create(vhost_worker
, dev
, "vhost-%d", current
->pid
);
506 if (IS_ERR(worker
)) {
507 err
= PTR_ERR(worker
);
511 dev
->worker
= worker
;
512 wake_up_process(worker
); /* avoid contributing to loadavg */
514 err
= vhost_attach_cgroups(dev
);
518 err
= vhost_dev_alloc_iovecs(dev
);
524 kthread_stop(worker
);
533 EXPORT_SYMBOL_GPL(vhost_dev_set_owner
);
535 static void *vhost_kvzalloc(unsigned long size
)
537 void *n
= kzalloc(size
, GFP_KERNEL
| __GFP_NOWARN
| __GFP_REPEAT
);
544 struct vhost_umem
*vhost_dev_reset_owner_prepare(void)
546 return vhost_kvzalloc(sizeof(struct vhost_umem
));
548 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare
);
550 /* Caller should have device mutex */
551 void vhost_dev_reset_owner(struct vhost_dev
*dev
, struct vhost_umem
*umem
)
555 vhost_dev_cleanup(dev
, true);
557 /* Restore memory to default empty mapping. */
558 INIT_LIST_HEAD(&umem
->umem_list
);
560 /* We don't need VQ locks below since vhost_dev_cleanup makes sure
561 * VQs aren't running.
563 for (i
= 0; i
< dev
->nvqs
; ++i
)
564 dev
->vqs
[i
]->umem
= umem
;
566 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner
);
568 void vhost_dev_stop(struct vhost_dev
*dev
)
572 for (i
= 0; i
< dev
->nvqs
; ++i
) {
573 if (dev
->vqs
[i
]->kick
&& dev
->vqs
[i
]->handle_kick
) {
574 vhost_poll_stop(&dev
->vqs
[i
]->poll
);
575 vhost_poll_flush(&dev
->vqs
[i
]->poll
);
579 EXPORT_SYMBOL_GPL(vhost_dev_stop
);
581 static void vhost_umem_free(struct vhost_umem
*umem
,
582 struct vhost_umem_node
*node
)
584 vhost_umem_interval_tree_remove(node
, &umem
->umem_tree
);
585 list_del(&node
->link
);
590 static void vhost_umem_clean(struct vhost_umem
*umem
)
592 struct vhost_umem_node
*node
, *tmp
;
597 list_for_each_entry_safe(node
, tmp
, &umem
->umem_list
, link
)
598 vhost_umem_free(umem
, node
);
603 static void vhost_clear_msg(struct vhost_dev
*dev
)
605 struct vhost_msg_node
*node
, *n
;
607 spin_lock(&dev
->iotlb_lock
);
609 list_for_each_entry_safe(node
, n
, &dev
->read_list
, node
) {
610 list_del(&node
->node
);
614 list_for_each_entry_safe(node
, n
, &dev
->pending_list
, node
) {
615 list_del(&node
->node
);
619 spin_unlock(&dev
->iotlb_lock
);
622 /* Caller should have device mutex if and only if locked is set */
623 void vhost_dev_cleanup(struct vhost_dev
*dev
, bool locked
)
627 for (i
= 0; i
< dev
->nvqs
; ++i
) {
628 if (dev
->vqs
[i
]->error_ctx
)
629 eventfd_ctx_put(dev
->vqs
[i
]->error_ctx
);
630 if (dev
->vqs
[i
]->error
)
631 fput(dev
->vqs
[i
]->error
);
632 if (dev
->vqs
[i
]->kick
)
633 fput(dev
->vqs
[i
]->kick
);
634 if (dev
->vqs
[i
]->call_ctx
)
635 eventfd_ctx_put(dev
->vqs
[i
]->call_ctx
);
636 if (dev
->vqs
[i
]->call
)
637 fput(dev
->vqs
[i
]->call
);
638 vhost_vq_reset(dev
, dev
->vqs
[i
]);
640 vhost_dev_free_iovecs(dev
);
642 eventfd_ctx_put(dev
->log_ctx
);
646 dev
->log_file
= NULL
;
647 /* No one will access memory at this point */
648 vhost_umem_clean(dev
->umem
);
650 vhost_umem_clean(dev
->iotlb
);
652 vhost_clear_msg(dev
);
653 wake_up_interruptible_poll(&dev
->wait
, POLLIN
| POLLRDNORM
);
654 WARN_ON(!llist_empty(&dev
->work_list
));
656 kthread_stop(dev
->worker
);
663 EXPORT_SYMBOL_GPL(vhost_dev_cleanup
);
665 static int log_access_ok(void __user
*log_base
, u64 addr
, unsigned long sz
)
667 u64 a
= addr
/ VHOST_PAGE_SIZE
/ 8;
669 /* Make sure 64 bit math will not overflow. */
670 if (a
> ULONG_MAX
- (unsigned long)log_base
||
671 a
+ (unsigned long)log_base
> ULONG_MAX
)
674 return access_ok(VERIFY_WRITE
, log_base
+ a
,
675 (sz
+ VHOST_PAGE_SIZE
* 8 - 1) / VHOST_PAGE_SIZE
/ 8);
678 static bool vhost_overflow(u64 uaddr
, u64 size
)
680 /* Make sure 64 bit math will not overflow. */
681 return uaddr
> ULONG_MAX
|| size
> ULONG_MAX
|| uaddr
> ULONG_MAX
- size
;
684 /* Caller should have vq mutex and device mutex. */
685 static int vq_memory_access_ok(void __user
*log_base
, struct vhost_umem
*umem
,
688 struct vhost_umem_node
*node
;
693 list_for_each_entry(node
, &umem
->umem_list
, link
) {
694 unsigned long a
= node
->userspace_addr
;
696 if (vhost_overflow(node
->userspace_addr
, node
->size
))
700 if (!access_ok(VERIFY_WRITE
, (void __user
*)a
,
703 else if (log_all
&& !log_access_ok(log_base
,
711 static inline void __user
*vhost_vq_meta_fetch(struct vhost_virtqueue
*vq
,
712 u64 addr
, unsigned int size
,
715 const struct vhost_umem_node
*node
= vq
->meta_iotlb
[type
];
720 return (void *)(uintptr_t)(node
->userspace_addr
+ addr
- node
->start
);
723 /* Can we switch to this memory table? */
724 /* Caller should have device mutex but not vq mutex */
725 static int memory_access_ok(struct vhost_dev
*d
, struct vhost_umem
*umem
,
730 for (i
= 0; i
< d
->nvqs
; ++i
) {
734 mutex_lock(&d
->vqs
[i
]->mutex
);
735 log
= log_all
|| vhost_has_feature(d
->vqs
[i
], VHOST_F_LOG_ALL
);
736 /* If ring is inactive, will check when it's enabled. */
737 if (d
->vqs
[i
]->private_data
)
738 ok
= vq_memory_access_ok(d
->vqs
[i
]->log_base
,
742 mutex_unlock(&d
->vqs
[i
]->mutex
);
749 static int translate_desc(struct vhost_virtqueue
*vq
, u64 addr
, u32 len
,
750 struct iovec iov
[], int iov_size
, int access
);
752 static int vhost_copy_to_user(struct vhost_virtqueue
*vq
, void __user
*to
,
753 const void *from
, unsigned size
)
758 return __copy_to_user(to
, from
, size
);
760 /* This function should be called after iotlb
761 * prefetch, which means we're sure that all vq
762 * could be access through iotlb. So -EAGAIN should
763 * not happen in this case.
766 void __user
*uaddr
= vhost_vq_meta_fetch(vq
,
767 (u64
)(uintptr_t)to
, size
,
771 return __copy_to_user(uaddr
, from
, size
);
773 ret
= translate_desc(vq
, (u64
)(uintptr_t)to
, size
, vq
->iotlb_iov
,
774 ARRAY_SIZE(vq
->iotlb_iov
),
778 iov_iter_init(&t
, WRITE
, vq
->iotlb_iov
, ret
, size
);
779 ret
= copy_to_iter(from
, size
, &t
);
787 static int vhost_copy_from_user(struct vhost_virtqueue
*vq
, void *to
,
788 void __user
*from
, unsigned size
)
793 return __copy_from_user(to
, from
, size
);
795 /* This function should be called after iotlb
796 * prefetch, which means we're sure that vq
797 * could be access through iotlb. So -EAGAIN should
798 * not happen in this case.
800 void __user
*uaddr
= vhost_vq_meta_fetch(vq
,
801 (u64
)(uintptr_t)from
, size
,
806 return __copy_from_user(to
, uaddr
, size
);
808 ret
= translate_desc(vq
, (u64
)(uintptr_t)from
, size
, vq
->iotlb_iov
,
809 ARRAY_SIZE(vq
->iotlb_iov
),
812 vq_err(vq
, "IOTLB translation failure: uaddr "
813 "%p size 0x%llx\n", from
,
814 (unsigned long long) size
);
817 iov_iter_init(&f
, READ
, vq
->iotlb_iov
, ret
, size
);
818 ret
= copy_from_iter(to
, size
, &f
);
827 static void __user
*__vhost_get_user_slow(struct vhost_virtqueue
*vq
,
828 void __user
*addr
, unsigned int size
,
833 ret
= translate_desc(vq
, (u64
)(uintptr_t)addr
, size
, vq
->iotlb_iov
,
834 ARRAY_SIZE(vq
->iotlb_iov
),
837 vq_err(vq
, "IOTLB translation failure: uaddr "
838 "%p size 0x%llx\n", addr
,
839 (unsigned long long) size
);
843 if (ret
!= 1 || vq
->iotlb_iov
[0].iov_len
!= size
) {
844 vq_err(vq
, "Non atomic userspace memory access: uaddr "
845 "%p size 0x%llx\n", addr
,
846 (unsigned long long) size
);
850 return vq
->iotlb_iov
[0].iov_base
;
853 /* This function should be called after iotlb
854 * prefetch, which means we're sure that vq
855 * could be access through iotlb. So -EAGAIN should
856 * not happen in this case.
858 static inline void __user
*__vhost_get_user(struct vhost_virtqueue
*vq
,
859 void *addr
, unsigned int size
,
862 void __user
*uaddr
= vhost_vq_meta_fetch(vq
,
863 (u64
)(uintptr_t)addr
, size
, type
);
867 return __vhost_get_user_slow(vq
, addr
, size
, type
);
870 #define vhost_put_user(vq, x, ptr) \
874 ret = __put_user(x, ptr); \
876 __typeof__(ptr) to = \
877 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
878 sizeof(*ptr), VHOST_ADDR_USED); \
880 ret = __put_user(x, to); \
887 #define vhost_get_user(vq, x, ptr, type) \
891 ret = __get_user(x, ptr); \
893 __typeof__(ptr) from = \
894 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \
898 ret = __get_user(x, from); \
905 #define vhost_get_avail(vq, x, ptr) \
906 vhost_get_user(vq, x, ptr, VHOST_ADDR_AVAIL)
908 #define vhost_get_used(vq, x, ptr) \
909 vhost_get_user(vq, x, ptr, VHOST_ADDR_USED)
911 static void vhost_dev_lock_vqs(struct vhost_dev
*d
)
914 for (i
= 0; i
< d
->nvqs
; ++i
)
915 mutex_lock(&d
->vqs
[i
]->mutex
);
918 static void vhost_dev_unlock_vqs(struct vhost_dev
*d
)
921 for (i
= 0; i
< d
->nvqs
; ++i
)
922 mutex_unlock(&d
->vqs
[i
]->mutex
);
925 static int vhost_new_umem_range(struct vhost_umem
*umem
,
926 u64 start
, u64 size
, u64 end
,
927 u64 userspace_addr
, int perm
)
929 struct vhost_umem_node
*tmp
, *node
= kmalloc(sizeof(*node
), GFP_ATOMIC
);
934 if (umem
->numem
== max_iotlb_entries
) {
935 tmp
= list_first_entry(&umem
->umem_list
, typeof(*tmp
), link
);
936 vhost_umem_free(umem
, tmp
);
942 node
->userspace_addr
= userspace_addr
;
944 INIT_LIST_HEAD(&node
->link
);
945 list_add_tail(&node
->link
, &umem
->umem_list
);
946 vhost_umem_interval_tree_insert(node
, &umem
->umem_tree
);
952 static void vhost_del_umem_range(struct vhost_umem
*umem
,
955 struct vhost_umem_node
*node
;
957 while ((node
= vhost_umem_interval_tree_iter_first(&umem
->umem_tree
,
959 vhost_umem_free(umem
, node
);
962 static void vhost_iotlb_notify_vq(struct vhost_dev
*d
,
963 struct vhost_iotlb_msg
*msg
)
965 struct vhost_msg_node
*node
, *n
;
967 spin_lock(&d
->iotlb_lock
);
969 list_for_each_entry_safe(node
, n
, &d
->pending_list
, node
) {
970 struct vhost_iotlb_msg
*vq_msg
= &node
->msg
.iotlb
;
971 if (msg
->iova
<= vq_msg
->iova
&&
972 msg
->iova
+ msg
->size
- 1 > vq_msg
->iova
&&
973 vq_msg
->type
== VHOST_IOTLB_MISS
) {
974 vhost_poll_queue(&node
->vq
->poll
);
975 list_del(&node
->node
);
980 spin_unlock(&d
->iotlb_lock
);
983 static int umem_access_ok(u64 uaddr
, u64 size
, int access
)
985 unsigned long a
= uaddr
;
987 /* Make sure 64 bit math will not overflow. */
988 if (vhost_overflow(uaddr
, size
))
991 if ((access
& VHOST_ACCESS_RO
) &&
992 !access_ok(VERIFY_READ
, (void __user
*)a
, size
))
994 if ((access
& VHOST_ACCESS_WO
) &&
995 !access_ok(VERIFY_WRITE
, (void __user
*)a
, size
))
1000 static int vhost_process_iotlb_msg(struct vhost_dev
*dev
,
1001 struct vhost_iotlb_msg
*msg
)
1005 vhost_dev_lock_vqs(dev
);
1006 switch (msg
->type
) {
1007 case VHOST_IOTLB_UPDATE
:
1012 if (umem_access_ok(msg
->uaddr
, msg
->size
, msg
->perm
)) {
1016 vhost_vq_meta_reset(dev
);
1017 if (vhost_new_umem_range(dev
->iotlb
, msg
->iova
, msg
->size
,
1018 msg
->iova
+ msg
->size
- 1,
1019 msg
->uaddr
, msg
->perm
)) {
1023 vhost_iotlb_notify_vq(dev
, msg
);
1025 case VHOST_IOTLB_INVALIDATE
:
1026 vhost_vq_meta_reset(dev
);
1027 vhost_del_umem_range(dev
->iotlb
, msg
->iova
,
1028 msg
->iova
+ msg
->size
- 1);
1035 vhost_dev_unlock_vqs(dev
);
1038 ssize_t
vhost_chr_write_iter(struct vhost_dev
*dev
,
1039 struct iov_iter
*from
)
1041 struct vhost_msg_node node
;
1042 unsigned size
= sizeof(struct vhost_msg
);
1046 if (iov_iter_count(from
) < size
)
1048 ret
= copy_from_iter(&node
.msg
, size
, from
);
1052 switch (node
.msg
.type
) {
1053 case VHOST_IOTLB_MSG
:
1054 err
= vhost_process_iotlb_msg(dev
, &node
.msg
.iotlb
);
1066 EXPORT_SYMBOL(vhost_chr_write_iter
);
1068 unsigned int vhost_chr_poll(struct file
*file
, struct vhost_dev
*dev
,
1071 unsigned int mask
= 0;
1073 poll_wait(file
, &dev
->wait
, wait
);
1075 if (!list_empty(&dev
->read_list
))
1076 mask
|= POLLIN
| POLLRDNORM
;
1080 EXPORT_SYMBOL(vhost_chr_poll
);
1082 ssize_t
vhost_chr_read_iter(struct vhost_dev
*dev
, struct iov_iter
*to
,
1086 struct vhost_msg_node
*node
;
1088 unsigned size
= sizeof(struct vhost_msg
);
1090 if (iov_iter_count(to
) < size
)
1095 prepare_to_wait(&dev
->wait
, &wait
,
1096 TASK_INTERRUPTIBLE
);
1098 node
= vhost_dequeue_msg(dev
, &dev
->read_list
);
1105 if (signal_pending(current
)) {
1118 finish_wait(&dev
->wait
, &wait
);
1121 ret
= copy_to_iter(&node
->msg
, size
, to
);
1123 if (ret
!= size
|| node
->msg
.type
!= VHOST_IOTLB_MISS
) {
1128 vhost_enqueue_msg(dev
, &dev
->pending_list
, node
);
1133 EXPORT_SYMBOL_GPL(vhost_chr_read_iter
);
1135 static int vhost_iotlb_miss(struct vhost_virtqueue
*vq
, u64 iova
, int access
)
1137 struct vhost_dev
*dev
= vq
->dev
;
1138 struct vhost_msg_node
*node
;
1139 struct vhost_iotlb_msg
*msg
;
1141 node
= vhost_new_msg(vq
, VHOST_IOTLB_MISS
);
1145 msg
= &node
->msg
.iotlb
;
1146 msg
->type
= VHOST_IOTLB_MISS
;
1150 vhost_enqueue_msg(dev
, &dev
->read_list
, node
);
1155 static int vq_access_ok(struct vhost_virtqueue
*vq
, unsigned int num
,
1156 struct vring_desc __user
*desc
,
1157 struct vring_avail __user
*avail
,
1158 struct vring_used __user
*used
)
1161 size_t s
= vhost_has_feature(vq
, VIRTIO_RING_F_EVENT_IDX
) ? 2 : 0;
1163 return access_ok(VERIFY_READ
, desc
, num
* sizeof *desc
) &&
1164 access_ok(VERIFY_READ
, avail
,
1165 sizeof *avail
+ num
* sizeof *avail
->ring
+ s
) &&
1166 access_ok(VERIFY_WRITE
, used
,
1167 sizeof *used
+ num
* sizeof *used
->ring
+ s
);
1170 static void vhost_vq_meta_update(struct vhost_virtqueue
*vq
,
1171 const struct vhost_umem_node
*node
,
1174 int access
= (type
== VHOST_ADDR_USED
) ?
1175 VHOST_ACCESS_WO
: VHOST_ACCESS_RO
;
1177 if (likely(node
->perm
& access
))
1178 vq
->meta_iotlb
[type
] = node
;
1181 static int iotlb_access_ok(struct vhost_virtqueue
*vq
,
1182 int access
, u64 addr
, u64 len
, int type
)
1184 const struct vhost_umem_node
*node
;
1185 struct vhost_umem
*umem
= vq
->iotlb
;
1186 u64 s
= 0, size
, orig_addr
= addr
;
1188 if (vhost_vq_meta_fetch(vq
, addr
, len
, type
))
1192 node
= vhost_umem_interval_tree_iter_first(&umem
->umem_tree
,
1195 if (node
== NULL
|| node
->start
> addr
) {
1196 vhost_iotlb_miss(vq
, addr
, access
);
1198 } else if (!(node
->perm
& access
)) {
1199 /* Report the possible access violation by
1200 * request another translation from userspace.
1205 size
= node
->size
- addr
+ node
->start
;
1207 if (orig_addr
== addr
&& size
>= len
)
1208 vhost_vq_meta_update(vq
, node
, type
);
1217 int vq_iotlb_prefetch(struct vhost_virtqueue
*vq
)
1219 size_t s
= vhost_has_feature(vq
, VIRTIO_RING_F_EVENT_IDX
) ? 2 : 0;
1220 unsigned int num
= vq
->num
;
1225 return iotlb_access_ok(vq
, VHOST_ACCESS_RO
, (u64
)(uintptr_t)vq
->desc
,
1226 num
* sizeof(*vq
->desc
), VHOST_ADDR_DESC
) &&
1227 iotlb_access_ok(vq
, VHOST_ACCESS_RO
, (u64
)(uintptr_t)vq
->avail
,
1229 num
* sizeof(*vq
->avail
->ring
) + s
,
1230 VHOST_ADDR_AVAIL
) &&
1231 iotlb_access_ok(vq
, VHOST_ACCESS_WO
, (u64
)(uintptr_t)vq
->used
,
1233 num
* sizeof(*vq
->used
->ring
) + s
,
1236 EXPORT_SYMBOL_GPL(vq_iotlb_prefetch
);
1238 /* Can we log writes? */
1239 /* Caller should have device mutex but not vq mutex */
1240 int vhost_log_access_ok(struct vhost_dev
*dev
)
1242 return memory_access_ok(dev
, dev
->umem
, 1);
1244 EXPORT_SYMBOL_GPL(vhost_log_access_ok
);
1246 /* Verify access for write logging. */
1247 /* Caller should have vq mutex and device mutex */
1248 static int vq_log_access_ok(struct vhost_virtqueue
*vq
,
1249 void __user
*log_base
)
1251 size_t s
= vhost_has_feature(vq
, VIRTIO_RING_F_EVENT_IDX
) ? 2 : 0;
1253 return vq_memory_access_ok(log_base
, vq
->umem
,
1254 vhost_has_feature(vq
, VHOST_F_LOG_ALL
)) &&
1255 (!vq
->log_used
|| log_access_ok(log_base
, vq
->log_addr
,
1257 vq
->num
* sizeof *vq
->used
->ring
+ s
));
1260 /* Can we start vq? */
1261 /* Caller should have vq mutex and device mutex */
1262 int vhost_vq_access_ok(struct vhost_virtqueue
*vq
)
1265 /* When device IOTLB was used, the access validation
1266 * will be validated during prefetching.
1270 return vq_access_ok(vq
, vq
->num
, vq
->desc
, vq
->avail
, vq
->used
) &&
1271 vq_log_access_ok(vq
, vq
->log_base
);
1273 EXPORT_SYMBOL_GPL(vhost_vq_access_ok
);
1275 static struct vhost_umem
*vhost_umem_alloc(void)
1277 struct vhost_umem
*umem
= vhost_kvzalloc(sizeof(*umem
));
1282 umem
->umem_tree
= RB_ROOT
;
1284 INIT_LIST_HEAD(&umem
->umem_list
);
1289 static long vhost_set_memory(struct vhost_dev
*d
, struct vhost_memory __user
*m
)
1291 struct vhost_memory mem
, *newmem
;
1292 struct vhost_memory_region
*region
;
1293 struct vhost_umem
*newumem
, *oldumem
;
1294 unsigned long size
= offsetof(struct vhost_memory
, regions
);
1297 if (copy_from_user(&mem
, m
, size
))
1301 if (mem
.nregions
> max_mem_regions
)
1303 newmem
= vhost_kvzalloc(size
+ mem
.nregions
* sizeof(*m
->regions
));
1307 memcpy(newmem
, &mem
, size
);
1308 if (copy_from_user(newmem
->regions
, m
->regions
,
1309 mem
.nregions
* sizeof *m
->regions
)) {
1314 newumem
= vhost_umem_alloc();
1320 for (region
= newmem
->regions
;
1321 region
< newmem
->regions
+ mem
.nregions
;
1323 if (vhost_new_umem_range(newumem
,
1324 region
->guest_phys_addr
,
1325 region
->memory_size
,
1326 region
->guest_phys_addr
+
1327 region
->memory_size
- 1,
1328 region
->userspace_addr
,
1333 if (!memory_access_ok(d
, newumem
, 0))
1339 /* All memory accesses are done under some VQ mutex. */
1340 for (i
= 0; i
< d
->nvqs
; ++i
) {
1341 mutex_lock(&d
->vqs
[i
]->mutex
);
1342 d
->vqs
[i
]->umem
= newumem
;
1343 mutex_unlock(&d
->vqs
[i
]->mutex
);
1347 vhost_umem_clean(oldumem
);
1351 vhost_umem_clean(newumem
);
1356 long vhost_vring_ioctl(struct vhost_dev
*d
, int ioctl
, void __user
*argp
)
1358 struct file
*eventfp
, *filep
= NULL
;
1359 bool pollstart
= false, pollstop
= false;
1360 struct eventfd_ctx
*ctx
= NULL
;
1361 u32 __user
*idxp
= argp
;
1362 struct vhost_virtqueue
*vq
;
1363 struct vhost_vring_state s
;
1364 struct vhost_vring_file f
;
1365 struct vhost_vring_addr a
;
1369 r
= get_user(idx
, idxp
);
1377 mutex_lock(&vq
->mutex
);
1380 case VHOST_SET_VRING_NUM
:
1381 /* Resizing ring with an active backend?
1382 * You don't want to do that. */
1383 if (vq
->private_data
) {
1387 if (copy_from_user(&s
, argp
, sizeof s
)) {
1391 if (!s
.num
|| s
.num
> 0xffff || (s
.num
& (s
.num
- 1))) {
1397 case VHOST_SET_VRING_BASE
:
1398 /* Moving base with an active backend?
1399 * You don't want to do that. */
1400 if (vq
->private_data
) {
1404 if (copy_from_user(&s
, argp
, sizeof s
)) {
1408 if (s
.num
> 0xffff) {
1412 vq
->last_avail_idx
= vq
->last_used_event
= s
.num
;
1413 /* Forget the cached index value. */
1414 vq
->avail_idx
= vq
->last_avail_idx
;
1416 case VHOST_GET_VRING_BASE
:
1418 s
.num
= vq
->last_avail_idx
;
1419 if (copy_to_user(argp
, &s
, sizeof s
))
1422 case VHOST_SET_VRING_ADDR
:
1423 if (copy_from_user(&a
, argp
, sizeof a
)) {
1427 if (a
.flags
& ~(0x1 << VHOST_VRING_F_LOG
)) {
1431 /* For 32bit, verify that the top 32bits of the user
1432 data are set to zero. */
1433 if ((u64
)(unsigned long)a
.desc_user_addr
!= a
.desc_user_addr
||
1434 (u64
)(unsigned long)a
.used_user_addr
!= a
.used_user_addr
||
1435 (u64
)(unsigned long)a
.avail_user_addr
!= a
.avail_user_addr
) {
1440 /* Make sure it's safe to cast pointers to vring types. */
1441 BUILD_BUG_ON(__alignof__
*vq
->avail
> VRING_AVAIL_ALIGN_SIZE
);
1442 BUILD_BUG_ON(__alignof__
*vq
->used
> VRING_USED_ALIGN_SIZE
);
1443 if ((a
.avail_user_addr
& (VRING_AVAIL_ALIGN_SIZE
- 1)) ||
1444 (a
.used_user_addr
& (VRING_USED_ALIGN_SIZE
- 1)) ||
1445 (a
.log_guest_addr
& (VRING_USED_ALIGN_SIZE
- 1))) {
1450 /* We only verify access here if backend is configured.
1451 * If it is not, we don't as size might not have been setup.
1452 * We will verify when backend is configured. */
1453 if (vq
->private_data
) {
1454 if (!vq_access_ok(vq
, vq
->num
,
1455 (void __user
*)(unsigned long)a
.desc_user_addr
,
1456 (void __user
*)(unsigned long)a
.avail_user_addr
,
1457 (void __user
*)(unsigned long)a
.used_user_addr
)) {
1462 /* Also validate log access for used ring if enabled. */
1463 if ((a
.flags
& (0x1 << VHOST_VRING_F_LOG
)) &&
1464 !log_access_ok(vq
->log_base
, a
.log_guest_addr
,
1466 vq
->num
* sizeof *vq
->used
->ring
)) {
1472 vq
->log_used
= !!(a
.flags
& (0x1 << VHOST_VRING_F_LOG
));
1473 vq
->desc
= (void __user
*)(unsigned long)a
.desc_user_addr
;
1474 vq
->avail
= (void __user
*)(unsigned long)a
.avail_user_addr
;
1475 vq
->log_addr
= a
.log_guest_addr
;
1476 vq
->used
= (void __user
*)(unsigned long)a
.used_user_addr
;
1478 case VHOST_SET_VRING_KICK
:
1479 if (copy_from_user(&f
, argp
, sizeof f
)) {
1483 eventfp
= f
.fd
== -1 ? NULL
: eventfd_fget(f
.fd
);
1484 if (IS_ERR(eventfp
)) {
1485 r
= PTR_ERR(eventfp
);
1488 if (eventfp
!= vq
->kick
) {
1489 pollstop
= (filep
= vq
->kick
) != NULL
;
1490 pollstart
= (vq
->kick
= eventfp
) != NULL
;
1494 case VHOST_SET_VRING_CALL
:
1495 if (copy_from_user(&f
, argp
, sizeof f
)) {
1499 eventfp
= f
.fd
== -1 ? NULL
: eventfd_fget(f
.fd
);
1500 if (IS_ERR(eventfp
)) {
1501 r
= PTR_ERR(eventfp
);
1504 if (eventfp
!= vq
->call
) {
1508 vq
->call_ctx
= eventfp
?
1509 eventfd_ctx_fileget(eventfp
) : NULL
;
1513 case VHOST_SET_VRING_ERR
:
1514 if (copy_from_user(&f
, argp
, sizeof f
)) {
1518 eventfp
= f
.fd
== -1 ? NULL
: eventfd_fget(f
.fd
);
1519 if (IS_ERR(eventfp
)) {
1520 r
= PTR_ERR(eventfp
);
1523 if (eventfp
!= vq
->error
) {
1525 vq
->error
= eventfp
;
1526 ctx
= vq
->error_ctx
;
1527 vq
->error_ctx
= eventfp
?
1528 eventfd_ctx_fileget(eventfp
) : NULL
;
1532 case VHOST_SET_VRING_ENDIAN
:
1533 r
= vhost_set_vring_endian(vq
, argp
);
1535 case VHOST_GET_VRING_ENDIAN
:
1536 r
= vhost_get_vring_endian(vq
, idx
, argp
);
1538 case VHOST_SET_VRING_BUSYLOOP_TIMEOUT
:
1539 if (copy_from_user(&s
, argp
, sizeof(s
))) {
1543 vq
->busyloop_timeout
= s
.num
;
1545 case VHOST_GET_VRING_BUSYLOOP_TIMEOUT
:
1547 s
.num
= vq
->busyloop_timeout
;
1548 if (copy_to_user(argp
, &s
, sizeof(s
)))
1555 if (pollstop
&& vq
->handle_kick
)
1556 vhost_poll_stop(&vq
->poll
);
1559 eventfd_ctx_put(ctx
);
1563 if (pollstart
&& vq
->handle_kick
)
1564 r
= vhost_poll_start(&vq
->poll
, vq
->kick
);
1566 mutex_unlock(&vq
->mutex
);
1568 if (pollstop
&& vq
->handle_kick
)
1569 vhost_poll_flush(&vq
->poll
);
1572 EXPORT_SYMBOL_GPL(vhost_vring_ioctl
);
1574 int vhost_init_device_iotlb(struct vhost_dev
*d
, bool enabled
)
1576 struct vhost_umem
*niotlb
, *oiotlb
;
1579 niotlb
= vhost_umem_alloc();
1586 for (i
= 0; i
< d
->nvqs
; ++i
) {
1587 mutex_lock(&d
->vqs
[i
]->mutex
);
1588 d
->vqs
[i
]->iotlb
= niotlb
;
1589 mutex_unlock(&d
->vqs
[i
]->mutex
);
1592 vhost_umem_clean(oiotlb
);
1596 EXPORT_SYMBOL_GPL(vhost_init_device_iotlb
);
1598 /* Caller must have device mutex */
1599 long vhost_dev_ioctl(struct vhost_dev
*d
, unsigned int ioctl
, void __user
*argp
)
1601 struct file
*eventfp
, *filep
= NULL
;
1602 struct eventfd_ctx
*ctx
= NULL
;
1607 /* If you are not the owner, you can become one */
1608 if (ioctl
== VHOST_SET_OWNER
) {
1609 r
= vhost_dev_set_owner(d
);
1613 /* You must be the owner to do anything else */
1614 r
= vhost_dev_check_owner(d
);
1619 case VHOST_SET_MEM_TABLE
:
1620 r
= vhost_set_memory(d
, argp
);
1622 case VHOST_SET_LOG_BASE
:
1623 if (copy_from_user(&p
, argp
, sizeof p
)) {
1627 if ((u64
)(unsigned long)p
!= p
) {
1631 for (i
= 0; i
< d
->nvqs
; ++i
) {
1632 struct vhost_virtqueue
*vq
;
1633 void __user
*base
= (void __user
*)(unsigned long)p
;
1635 mutex_lock(&vq
->mutex
);
1636 /* If ring is inactive, will check when it's enabled. */
1637 if (vq
->private_data
&& !vq_log_access_ok(vq
, base
))
1640 vq
->log_base
= base
;
1641 mutex_unlock(&vq
->mutex
);
1644 case VHOST_SET_LOG_FD
:
1645 r
= get_user(fd
, (int __user
*)argp
);
1648 eventfp
= fd
== -1 ? NULL
: eventfd_fget(fd
);
1649 if (IS_ERR(eventfp
)) {
1650 r
= PTR_ERR(eventfp
);
1653 if (eventfp
!= d
->log_file
) {
1654 filep
= d
->log_file
;
1655 d
->log_file
= eventfp
;
1657 d
->log_ctx
= eventfp
?
1658 eventfd_ctx_fileget(eventfp
) : NULL
;
1661 for (i
= 0; i
< d
->nvqs
; ++i
) {
1662 mutex_lock(&d
->vqs
[i
]->mutex
);
1663 d
->vqs
[i
]->log_ctx
= d
->log_ctx
;
1664 mutex_unlock(&d
->vqs
[i
]->mutex
);
1667 eventfd_ctx_put(ctx
);
1678 EXPORT_SYMBOL_GPL(vhost_dev_ioctl
);
1680 /* TODO: This is really inefficient. We need something like get_user()
1681 * (instruction directly accesses the data, with an exception table entry
1682 * returning -EFAULT). See Documentation/x86/exception-tables.txt.
1684 static int set_bit_to_user(int nr
, void __user
*addr
)
1686 unsigned long log
= (unsigned long)addr
;
1689 int bit
= nr
+ (log
% PAGE_SIZE
) * 8;
1692 r
= get_user_pages_fast(log
, 1, 1, &page
);
1696 base
= kmap_atomic(page
);
1698 kunmap_atomic(base
);
1699 set_page_dirty_lock(page
);
1704 static int log_write(void __user
*log_base
,
1705 u64 write_address
, u64 write_length
)
1707 u64 write_page
= write_address
/ VHOST_PAGE_SIZE
;
1712 write_length
+= write_address
% VHOST_PAGE_SIZE
;
1714 u64 base
= (u64
)(unsigned long)log_base
;
1715 u64 log
= base
+ write_page
/ 8;
1716 int bit
= write_page
% 8;
1717 if ((u64
)(unsigned long)log
!= log
)
1719 r
= set_bit_to_user(bit
, (void __user
*)(unsigned long)log
);
1722 if (write_length
<= VHOST_PAGE_SIZE
)
1724 write_length
-= VHOST_PAGE_SIZE
;
1730 int vhost_log_write(struct vhost_virtqueue
*vq
, struct vhost_log
*log
,
1731 unsigned int log_num
, u64 len
)
1735 /* Make sure data written is seen before log. */
1737 for (i
= 0; i
< log_num
; ++i
) {
1738 u64 l
= min(log
[i
].len
, len
);
1739 r
= log_write(vq
->log_base
, log
[i
].addr
, l
);
1745 eventfd_signal(vq
->log_ctx
, 1);
1749 /* Length written exceeds what we have stored. This is a bug. */
1753 EXPORT_SYMBOL_GPL(vhost_log_write
);
1755 static int vhost_update_used_flags(struct vhost_virtqueue
*vq
)
1758 if (vhost_put_user(vq
, cpu_to_vhost16(vq
, vq
->used_flags
),
1759 &vq
->used
->flags
) < 0)
1761 if (unlikely(vq
->log_used
)) {
1762 /* Make sure the flag is seen before log. */
1764 /* Log used flag write. */
1765 used
= &vq
->used
->flags
;
1766 log_write(vq
->log_base
, vq
->log_addr
+
1767 (used
- (void __user
*)vq
->used
),
1768 sizeof vq
->used
->flags
);
1770 eventfd_signal(vq
->log_ctx
, 1);
1775 static int vhost_update_avail_event(struct vhost_virtqueue
*vq
, u16 avail_event
)
1777 if (vhost_put_user(vq
, cpu_to_vhost16(vq
, vq
->avail_idx
),
1778 vhost_avail_event(vq
)))
1780 if (unlikely(vq
->log_used
)) {
1782 /* Make sure the event is seen before log. */
1784 /* Log avail event write */
1785 used
= vhost_avail_event(vq
);
1786 log_write(vq
->log_base
, vq
->log_addr
+
1787 (used
- (void __user
*)vq
->used
),
1788 sizeof *vhost_avail_event(vq
));
1790 eventfd_signal(vq
->log_ctx
, 1);
1795 int vhost_vq_init_access(struct vhost_virtqueue
*vq
)
1797 __virtio16 last_used_idx
;
1799 bool is_le
= vq
->is_le
;
1801 if (!vq
->private_data
)
1804 vhost_init_is_le(vq
);
1806 r
= vhost_update_used_flags(vq
);
1809 vq
->signalled_used_valid
= false;
1811 !access_ok(VERIFY_READ
, &vq
->used
->idx
, sizeof vq
->used
->idx
)) {
1815 r
= vhost_get_used(vq
, last_used_idx
, &vq
->used
->idx
);
1817 vq_err(vq
, "Can't access used idx at %p\n",
1821 vq
->last_used_idx
= vhost16_to_cpu(vq
, last_used_idx
);
1828 EXPORT_SYMBOL_GPL(vhost_vq_init_access
);
1830 static int translate_desc(struct vhost_virtqueue
*vq
, u64 addr
, u32 len
,
1831 struct iovec iov
[], int iov_size
, int access
)
1833 const struct vhost_umem_node
*node
;
1834 struct vhost_dev
*dev
= vq
->dev
;
1835 struct vhost_umem
*umem
= dev
->iotlb
? dev
->iotlb
: dev
->umem
;
1840 while ((u64
)len
> s
) {
1842 if (unlikely(ret
>= iov_size
)) {
1847 node
= vhost_umem_interval_tree_iter_first(&umem
->umem_tree
,
1848 addr
, addr
+ len
- 1);
1849 if (node
== NULL
|| node
->start
> addr
) {
1850 if (umem
!= dev
->iotlb
) {
1856 } else if (!(node
->perm
& access
)) {
1862 size
= node
->size
- addr
+ node
->start
;
1863 _iov
->iov_len
= min((u64
)len
- s
, size
);
1864 _iov
->iov_base
= (void __user
*)(unsigned long)
1865 (node
->userspace_addr
+ addr
- node
->start
);
1872 vhost_iotlb_miss(vq
, addr
, access
);
1876 /* Each buffer in the virtqueues is actually a chain of descriptors. This
1877 * function returns the next descriptor in the chain,
1878 * or -1U if we're at the end. */
1879 static unsigned next_desc(struct vhost_virtqueue
*vq
, struct vring_desc
*desc
)
1883 /* If this descriptor says it doesn't chain, we're done. */
1884 if (!(desc
->flags
& cpu_to_vhost16(vq
, VRING_DESC_F_NEXT
)))
1887 /* Check they're not leading us off end of descriptors. */
1888 next
= vhost16_to_cpu(vq
, desc
->next
);
1889 /* Make sure compiler knows to grab that: we don't want it changing! */
1890 /* We will use the result as an index in an array, so most
1891 * architectures only need a compiler barrier here. */
1892 read_barrier_depends();
1897 static int get_indirect(struct vhost_virtqueue
*vq
,
1898 struct iovec iov
[], unsigned int iov_size
,
1899 unsigned int *out_num
, unsigned int *in_num
,
1900 struct vhost_log
*log
, unsigned int *log_num
,
1901 struct vring_desc
*indirect
)
1903 struct vring_desc desc
;
1904 unsigned int i
= 0, count
, found
= 0;
1905 u32 len
= vhost32_to_cpu(vq
, indirect
->len
);
1906 struct iov_iter from
;
1910 if (unlikely(len
% sizeof desc
)) {
1911 vq_err(vq
, "Invalid length in indirect descriptor: "
1912 "len 0x%llx not multiple of 0x%zx\n",
1913 (unsigned long long)len
,
1918 ret
= translate_desc(vq
, vhost64_to_cpu(vq
, indirect
->addr
), len
, vq
->indirect
,
1919 UIO_MAXIOV
, VHOST_ACCESS_RO
);
1920 if (unlikely(ret
< 0)) {
1922 vq_err(vq
, "Translation failure %d in indirect.\n", ret
);
1925 iov_iter_init(&from
, READ
, vq
->indirect
, ret
, len
);
1927 /* We will use the result as an address to read from, so most
1928 * architectures only need a compiler barrier here. */
1929 read_barrier_depends();
1931 count
= len
/ sizeof desc
;
1932 /* Buffers are chained via a 16 bit next field, so
1933 * we can have at most 2^16 of these. */
1934 if (unlikely(count
> USHRT_MAX
+ 1)) {
1935 vq_err(vq
, "Indirect buffer length too big: %d\n",
1941 unsigned iov_count
= *in_num
+ *out_num
;
1942 if (unlikely(++found
> count
)) {
1943 vq_err(vq
, "Loop detected: last one at %u "
1944 "indirect size %u\n",
1948 if (unlikely(!copy_from_iter_full(&desc
, sizeof(desc
), &from
))) {
1949 vq_err(vq
, "Failed indirect descriptor: idx %d, %zx\n",
1950 i
, (size_t)vhost64_to_cpu(vq
, indirect
->addr
) + i
* sizeof desc
);
1953 if (unlikely(desc
.flags
& cpu_to_vhost16(vq
, VRING_DESC_F_INDIRECT
))) {
1954 vq_err(vq
, "Nested indirect descriptor: idx %d, %zx\n",
1955 i
, (size_t)vhost64_to_cpu(vq
, indirect
->addr
) + i
* sizeof desc
);
1959 if (desc
.flags
& cpu_to_vhost16(vq
, VRING_DESC_F_WRITE
))
1960 access
= VHOST_ACCESS_WO
;
1962 access
= VHOST_ACCESS_RO
;
1964 ret
= translate_desc(vq
, vhost64_to_cpu(vq
, desc
.addr
),
1965 vhost32_to_cpu(vq
, desc
.len
), iov
+ iov_count
,
1966 iov_size
- iov_count
, access
);
1967 if (unlikely(ret
< 0)) {
1969 vq_err(vq
, "Translation failure %d indirect idx %d\n",
1973 /* If this is an input descriptor, increment that count. */
1974 if (access
== VHOST_ACCESS_WO
) {
1976 if (unlikely(log
)) {
1977 log
[*log_num
].addr
= vhost64_to_cpu(vq
, desc
.addr
);
1978 log
[*log_num
].len
= vhost32_to_cpu(vq
, desc
.len
);
1982 /* If it's an output descriptor, they're all supposed
1983 * to come before any input descriptors. */
1984 if (unlikely(*in_num
)) {
1985 vq_err(vq
, "Indirect descriptor "
1986 "has out after in: idx %d\n", i
);
1991 } while ((i
= next_desc(vq
, &desc
)) != -1);
1995 /* This looks in the virtqueue and for the first available buffer, and converts
1996 * it to an iovec for convenient access. Since descriptors consist of some
1997 * number of output then some number of input descriptors, it's actually two
1998 * iovecs, but we pack them into one and note how many of each there were.
2000 * This function returns the descriptor number found, or vq->num (which is
2001 * never a valid descriptor number) if none was found. A negative code is
2002 * returned on error. */
2003 int vhost_get_vq_desc(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
)
2008 struct vring_desc desc
;
2009 unsigned int i
, head
, found
= 0;
2011 __virtio16 avail_idx
;
2012 __virtio16 ring_head
;
2015 /* Check it isn't doing very strange things with descriptor numbers. */
2016 last_avail_idx
= vq
->last_avail_idx
;
2018 if (vq
->avail_idx
== vq
->last_avail_idx
) {
2019 if (unlikely(vhost_get_avail(vq
, avail_idx
, &vq
->avail
->idx
))) {
2020 vq_err(vq
, "Failed to access avail idx at %p\n",
2024 vq
->avail_idx
= vhost16_to_cpu(vq
, avail_idx
);
2026 if (unlikely((u16
)(vq
->avail_idx
- last_avail_idx
) > vq
->num
)) {
2027 vq_err(vq
, "Guest moved used index from %u to %u",
2028 last_avail_idx
, vq
->avail_idx
);
2032 /* If there's nothing new since last we looked, return
2035 if (vq
->avail_idx
== last_avail_idx
)
2038 /* Only get avail ring entries after they have been
2044 /* Grab the next descriptor number they're advertising, and increment
2045 * the index we've seen. */
2046 if (unlikely(vhost_get_avail(vq
, ring_head
,
2047 &vq
->avail
->ring
[last_avail_idx
& (vq
->num
- 1)]))) {
2048 vq_err(vq
, "Failed to read head: idx %d address %p\n",
2050 &vq
->avail
->ring
[last_avail_idx
% vq
->num
]);
2054 head
= vhost16_to_cpu(vq
, ring_head
);
2056 /* If their number is silly, that's an error. */
2057 if (unlikely(head
>= vq
->num
)) {
2058 vq_err(vq
, "Guest says index %u > %u is available",
2063 /* When we start there are none of either input nor output. */
2064 *out_num
= *in_num
= 0;
2070 unsigned iov_count
= *in_num
+ *out_num
;
2071 if (unlikely(i
>= vq
->num
)) {
2072 vq_err(vq
, "Desc index is %u > %u, head = %u",
2076 if (unlikely(++found
> vq
->num
)) {
2077 vq_err(vq
, "Loop detected: last one at %u "
2078 "vq size %u head %u\n",
2082 ret
= vhost_copy_from_user(vq
, &desc
, vq
->desc
+ i
,
2084 if (unlikely(ret
)) {
2085 vq_err(vq
, "Failed to get descriptor: idx %d addr %p\n",
2089 if (desc
.flags
& cpu_to_vhost16(vq
, VRING_DESC_F_INDIRECT
)) {
2090 ret
= get_indirect(vq
, iov
, iov_size
,
2092 log
, log_num
, &desc
);
2093 if (unlikely(ret
< 0)) {
2095 vq_err(vq
, "Failure detected "
2096 "in indirect descriptor at idx %d\n", i
);
2102 if (desc
.flags
& cpu_to_vhost16(vq
, VRING_DESC_F_WRITE
))
2103 access
= VHOST_ACCESS_WO
;
2105 access
= VHOST_ACCESS_RO
;
2106 ret
= translate_desc(vq
, vhost64_to_cpu(vq
, desc
.addr
),
2107 vhost32_to_cpu(vq
, desc
.len
), iov
+ iov_count
,
2108 iov_size
- iov_count
, access
);
2109 if (unlikely(ret
< 0)) {
2111 vq_err(vq
, "Translation failure %d descriptor idx %d\n",
2115 if (access
== VHOST_ACCESS_WO
) {
2116 /* If this is an input descriptor,
2117 * increment that count. */
2119 if (unlikely(log
)) {
2120 log
[*log_num
].addr
= vhost64_to_cpu(vq
, desc
.addr
);
2121 log
[*log_num
].len
= vhost32_to_cpu(vq
, desc
.len
);
2125 /* If it's an output descriptor, they're all supposed
2126 * to come before any input descriptors. */
2127 if (unlikely(*in_num
)) {
2128 vq_err(vq
, "Descriptor has out after in: "
2134 } while ((i
= next_desc(vq
, &desc
)) != -1);
2136 /* On success, increment avail index. */
2137 vq
->last_avail_idx
++;
2139 /* Assume notifications from guest are disabled at this point,
2140 * if they aren't we would need to update avail_event index. */
2141 BUG_ON(!(vq
->used_flags
& VRING_USED_F_NO_NOTIFY
));
2144 EXPORT_SYMBOL_GPL(vhost_get_vq_desc
);
2146 /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
2147 void vhost_discard_vq_desc(struct vhost_virtqueue
*vq
, int n
)
2149 vq
->last_avail_idx
-= n
;
2151 EXPORT_SYMBOL_GPL(vhost_discard_vq_desc
);
2153 /* After we've used one of their buffers, we tell them about it. We'll then
2154 * want to notify the guest, using eventfd. */
2155 int vhost_add_used(struct vhost_virtqueue
*vq
, unsigned int head
, int len
)
2157 struct vring_used_elem heads
= {
2158 cpu_to_vhost32(vq
, head
),
2159 cpu_to_vhost32(vq
, len
)
2162 return vhost_add_used_n(vq
, &heads
, 1);
2164 EXPORT_SYMBOL_GPL(vhost_add_used
);
2166 static int __vhost_add_used_n(struct vhost_virtqueue
*vq
,
2167 struct vring_used_elem
*heads
,
2170 struct vring_used_elem __user
*used
;
2174 start
= vq
->last_used_idx
& (vq
->num
- 1);
2175 used
= vq
->used
->ring
+ start
;
2177 if (vhost_put_user(vq
, heads
[0].id
, &used
->id
)) {
2178 vq_err(vq
, "Failed to write used id");
2181 if (vhost_put_user(vq
, heads
[0].len
, &used
->len
)) {
2182 vq_err(vq
, "Failed to write used len");
2185 } else if (vhost_copy_to_user(vq
, used
, heads
, count
* sizeof *used
)) {
2186 vq_err(vq
, "Failed to write used");
2189 if (unlikely(vq
->log_used
)) {
2190 /* Make sure data is seen before log. */
2192 /* Log used ring entry write. */
2193 log_write(vq
->log_base
,
2195 ((void __user
*)used
- (void __user
*)vq
->used
),
2196 count
* sizeof *used
);
2198 old
= vq
->last_used_idx
;
2199 new = (vq
->last_used_idx
+= count
);
2200 /* If the driver never bothers to signal in a very long while,
2201 * used index might wrap around. If that happens, invalidate
2202 * signalled_used index we stored. TODO: make sure driver
2203 * signals at least once in 2^16 and remove this. */
2204 if (unlikely((u16
)(new - vq
->signalled_used
) < (u16
)(new - old
)))
2205 vq
->signalled_used_valid
= false;
2209 /* After we've used one of their buffers, we tell them about it. We'll then
2210 * want to notify the guest, using eventfd. */
2211 int vhost_add_used_n(struct vhost_virtqueue
*vq
, struct vring_used_elem
*heads
,
2216 start
= vq
->last_used_idx
& (vq
->num
- 1);
2217 n
= vq
->num
- start
;
2219 r
= __vhost_add_used_n(vq
, heads
, n
);
2225 r
= __vhost_add_used_n(vq
, heads
, count
);
2227 /* Make sure buffer is written before we update index. */
2229 if (vhost_put_user(vq
, cpu_to_vhost16(vq
, vq
->last_used_idx
),
2231 vq_err(vq
, "Failed to increment used idx");
2234 if (unlikely(vq
->log_used
)) {
2235 /* Log used index update. */
2236 log_write(vq
->log_base
,
2237 vq
->log_addr
+ offsetof(struct vring_used
, idx
),
2238 sizeof vq
->used
->idx
);
2240 eventfd_signal(vq
->log_ctx
, 1);
2244 EXPORT_SYMBOL_GPL(vhost_add_used_n
);
2246 static bool vhost_notify(struct vhost_dev
*dev
, struct vhost_virtqueue
*vq
)
2252 if (vhost_has_feature(vq
, VIRTIO_F_NOTIFY_ON_EMPTY
) &&
2253 unlikely(vq
->avail_idx
== vq
->last_avail_idx
))
2256 if (!vhost_has_feature(vq
, VIRTIO_RING_F_EVENT_IDX
)) {
2258 /* Flush out used index updates. This is paired
2259 * with the barrier that the Guest executes when enabling
2262 if (vhost_get_avail(vq
, flags
, &vq
->avail
->flags
)) {
2263 vq_err(vq
, "Failed to get flags");
2266 return !(flags
& cpu_to_vhost16(vq
, VRING_AVAIL_F_NO_INTERRUPT
));
2268 old
= vq
->signalled_used
;
2269 v
= vq
->signalled_used_valid
;
2270 new = vq
->signalled_used
= vq
->last_used_idx
;
2271 vq
->signalled_used_valid
= true;
2276 /* We're sure if the following conditions are met, there's no
2277 * need to notify guest:
2278 * 1) cached used event is ahead of new
2279 * 2) old to new updating does not cross cached used event. */
2280 if (vring_need_event(vq
->last_used_event
, new + vq
->num
, new) &&
2281 !vring_need_event(vq
->last_used_event
, new, old
))
2284 /* Flush out used index updates. This is paired
2285 * with the barrier that the Guest executes when enabling
2289 if (vhost_get_avail(vq
, event
, vhost_used_event(vq
))) {
2290 vq_err(vq
, "Failed to get used event idx");
2293 vq
->last_used_event
= vhost16_to_cpu(vq
, event
);
2295 return vring_need_event(vq
->last_used_event
, new, old
);
2298 /* This actually signals the guest, using eventfd. */
2299 void vhost_signal(struct vhost_dev
*dev
, struct vhost_virtqueue
*vq
)
2301 /* Signal the Guest tell them we used something up. */
2302 if (vq
->call_ctx
&& vhost_notify(dev
, vq
))
2303 eventfd_signal(vq
->call_ctx
, 1);
2305 EXPORT_SYMBOL_GPL(vhost_signal
);
2307 /* And here's the combo meal deal. Supersize me! */
2308 void vhost_add_used_and_signal(struct vhost_dev
*dev
,
2309 struct vhost_virtqueue
*vq
,
2310 unsigned int head
, int len
)
2312 vhost_add_used(vq
, head
, len
);
2313 vhost_signal(dev
, vq
);
2315 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal
);
2317 /* multi-buffer version of vhost_add_used_and_signal */
2318 void vhost_add_used_and_signal_n(struct vhost_dev
*dev
,
2319 struct vhost_virtqueue
*vq
,
2320 struct vring_used_elem
*heads
, unsigned count
)
2322 vhost_add_used_n(vq
, heads
, count
);
2323 vhost_signal(dev
, vq
);
2325 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n
);
2327 /* return true if we're sure that avaiable ring is empty */
2328 bool vhost_vq_avail_empty(struct vhost_dev
*dev
, struct vhost_virtqueue
*vq
)
2330 __virtio16 avail_idx
;
2333 r
= vhost_get_avail(vq
, avail_idx
, &vq
->avail
->idx
);
2337 return vhost16_to_cpu(vq
, avail_idx
) == vq
->avail_idx
;
2339 EXPORT_SYMBOL_GPL(vhost_vq_avail_empty
);
2341 /* OK, now we need to know about added descriptors. */
2342 bool vhost_enable_notify(struct vhost_dev
*dev
, struct vhost_virtqueue
*vq
)
2344 __virtio16 avail_idx
;
2347 if (!(vq
->used_flags
& VRING_USED_F_NO_NOTIFY
))
2349 vq
->used_flags
&= ~VRING_USED_F_NO_NOTIFY
;
2350 if (!vhost_has_feature(vq
, VIRTIO_RING_F_EVENT_IDX
)) {
2351 r
= vhost_update_used_flags(vq
);
2353 vq_err(vq
, "Failed to enable notification at %p: %d\n",
2354 &vq
->used
->flags
, r
);
2358 r
= vhost_update_avail_event(vq
, vq
->avail_idx
);
2360 vq_err(vq
, "Failed to update avail event index at %p: %d\n",
2361 vhost_avail_event(vq
), r
);
2365 /* They could have slipped one in as we were doing that: make
2366 * sure it's written, then check again. */
2368 r
= vhost_get_avail(vq
, avail_idx
, &vq
->avail
->idx
);
2370 vq_err(vq
, "Failed to check avail idx at %p: %d\n",
2371 &vq
->avail
->idx
, r
);
2375 return vhost16_to_cpu(vq
, avail_idx
) != vq
->avail_idx
;
2377 EXPORT_SYMBOL_GPL(vhost_enable_notify
);
2379 /* We don't need to be notified again. */
2380 void vhost_disable_notify(struct vhost_dev
*dev
, struct vhost_virtqueue
*vq
)
2384 if (vq
->used_flags
& VRING_USED_F_NO_NOTIFY
)
2386 vq
->used_flags
|= VRING_USED_F_NO_NOTIFY
;
2387 if (!vhost_has_feature(vq
, VIRTIO_RING_F_EVENT_IDX
)) {
2388 r
= vhost_update_used_flags(vq
);
2390 vq_err(vq
, "Failed to enable notification at %p: %d\n",
2391 &vq
->used
->flags
, r
);
2394 EXPORT_SYMBOL_GPL(vhost_disable_notify
);
2396 /* Create a new message. */
2397 struct vhost_msg_node
*vhost_new_msg(struct vhost_virtqueue
*vq
, int type
)
2399 struct vhost_msg_node
*node
= kmalloc(sizeof *node
, GFP_KERNEL
);
2403 node
->msg
.type
= type
;
2406 EXPORT_SYMBOL_GPL(vhost_new_msg
);
2408 void vhost_enqueue_msg(struct vhost_dev
*dev
, struct list_head
*head
,
2409 struct vhost_msg_node
*node
)
2411 spin_lock(&dev
->iotlb_lock
);
2412 list_add_tail(&node
->node
, head
);
2413 spin_unlock(&dev
->iotlb_lock
);
2415 wake_up_interruptible_poll(&dev
->wait
, POLLIN
| POLLRDNORM
);
2417 EXPORT_SYMBOL_GPL(vhost_enqueue_msg
);
2419 struct vhost_msg_node
*vhost_dequeue_msg(struct vhost_dev
*dev
,
2420 struct list_head
*head
)
2422 struct vhost_msg_node
*node
= NULL
;
2424 spin_lock(&dev
->iotlb_lock
);
2425 if (!list_empty(head
)) {
2426 node
= list_first_entry(head
, struct vhost_msg_node
,
2428 list_del(&node
->node
);
2430 spin_unlock(&dev
->iotlb_lock
);
2434 EXPORT_SYMBOL_GPL(vhost_dequeue_msg
);
2437 static int __init
vhost_init(void)
2442 static void __exit
vhost_exit(void)
2446 module_init(vhost_init
);
2447 module_exit(vhost_exit
);
2449 MODULE_VERSION("0.0.1");
2450 MODULE_LICENSE("GPL v2");
2451 MODULE_AUTHOR("Michael S. Tsirkin");
2452 MODULE_DESCRIPTION("Host kernel accelerator for virtio");