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>
33 static ushort max_mem_regions
= 64;
34 module_param(max_mem_regions
, ushort
, 0444);
35 MODULE_PARM_DESC(max_mem_regions
,
36 "Maximum number of memory regions in memory map. (default: 64)");
39 VHOST_MEMORY_F_LOG
= 0x1,
42 #define vhost_used_event(vq) ((__virtio16 __user *)&vq->avail->ring[vq->num])
43 #define vhost_avail_event(vq) ((__virtio16 __user *)&vq->used->ring[vq->num])
45 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY
46 static void vhost_disable_cross_endian(struct vhost_virtqueue
*vq
)
48 vq
->user_be
= !virtio_legacy_is_little_endian();
51 static void vhost_enable_cross_endian_big(struct vhost_virtqueue
*vq
)
56 static void vhost_enable_cross_endian_little(struct vhost_virtqueue
*vq
)
61 static long vhost_set_vring_endian(struct vhost_virtqueue
*vq
, int __user
*argp
)
63 struct vhost_vring_state s
;
68 if (copy_from_user(&s
, argp
, sizeof(s
)))
71 if (s
.num
!= VHOST_VRING_LITTLE_ENDIAN
&&
72 s
.num
!= VHOST_VRING_BIG_ENDIAN
)
75 if (s
.num
== VHOST_VRING_BIG_ENDIAN
)
76 vhost_enable_cross_endian_big(vq
);
78 vhost_enable_cross_endian_little(vq
);
83 static long vhost_get_vring_endian(struct vhost_virtqueue
*vq
, u32 idx
,
86 struct vhost_vring_state s
= {
91 if (copy_to_user(argp
, &s
, sizeof(s
)))
97 static void vhost_init_is_le(struct vhost_virtqueue
*vq
)
99 /* Note for legacy virtio: user_be is initialized at reset time
100 * according to the host endianness. If userspace does not set an
101 * explicit endianness, the default behavior is native endian, as
102 * expected by legacy virtio.
104 vq
->is_le
= vhost_has_feature(vq
, VIRTIO_F_VERSION_1
) || !vq
->user_be
;
107 static void vhost_disable_cross_endian(struct vhost_virtqueue
*vq
)
111 static long vhost_set_vring_endian(struct vhost_virtqueue
*vq
, int __user
*argp
)
116 static long vhost_get_vring_endian(struct vhost_virtqueue
*vq
, u32 idx
,
122 static void vhost_init_is_le(struct vhost_virtqueue
*vq
)
124 if (vhost_has_feature(vq
, VIRTIO_F_VERSION_1
))
127 #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
129 static void vhost_reset_is_le(struct vhost_virtqueue
*vq
)
131 vq
->is_le
= virtio_legacy_is_little_endian();
134 struct vhost_flush_struct
{
135 struct vhost_work work
;
136 struct completion wait_event
;
139 static void vhost_flush_work(struct vhost_work
*work
)
141 struct vhost_flush_struct
*s
;
143 s
= container_of(work
, struct vhost_flush_struct
, work
);
144 complete(&s
->wait_event
);
147 static void vhost_poll_func(struct file
*file
, wait_queue_head_t
*wqh
,
150 struct vhost_poll
*poll
;
152 poll
= container_of(pt
, struct vhost_poll
, table
);
154 add_wait_queue(wqh
, &poll
->wait
);
157 static int vhost_poll_wakeup(wait_queue_t
*wait
, unsigned mode
, int sync
,
160 struct vhost_poll
*poll
= container_of(wait
, struct vhost_poll
, wait
);
162 if (!((unsigned long)key
& poll
->mask
))
165 vhost_poll_queue(poll
);
169 void vhost_work_init(struct vhost_work
*work
, vhost_work_fn_t fn
)
171 clear_bit(VHOST_WORK_QUEUED
, &work
->flags
);
173 init_waitqueue_head(&work
->done
);
175 EXPORT_SYMBOL_GPL(vhost_work_init
);
177 /* Init poll structure */
178 void vhost_poll_init(struct vhost_poll
*poll
, vhost_work_fn_t fn
,
179 unsigned long mask
, struct vhost_dev
*dev
)
181 init_waitqueue_func_entry(&poll
->wait
, vhost_poll_wakeup
);
182 init_poll_funcptr(&poll
->table
, vhost_poll_func
);
187 vhost_work_init(&poll
->work
, fn
);
189 EXPORT_SYMBOL_GPL(vhost_poll_init
);
191 /* Start polling a file. We add ourselves to file's wait queue. The caller must
192 * keep a reference to a file until after vhost_poll_stop is called. */
193 int vhost_poll_start(struct vhost_poll
*poll
, struct file
*file
)
201 mask
= file
->f_op
->poll(file
, &poll
->table
);
203 vhost_poll_wakeup(&poll
->wait
, 0, 0, (void *)mask
);
204 if (mask
& POLLERR
) {
206 remove_wait_queue(poll
->wqh
, &poll
->wait
);
212 EXPORT_SYMBOL_GPL(vhost_poll_start
);
214 /* Stop polling a file. After this function returns, it becomes safe to drop the
215 * file reference. You must also flush afterwards. */
216 void vhost_poll_stop(struct vhost_poll
*poll
)
219 remove_wait_queue(poll
->wqh
, &poll
->wait
);
223 EXPORT_SYMBOL_GPL(vhost_poll_stop
);
225 void vhost_work_flush(struct vhost_dev
*dev
, struct vhost_work
*work
)
227 struct vhost_flush_struct flush
;
230 init_completion(&flush
.wait_event
);
231 vhost_work_init(&flush
.work
, vhost_flush_work
);
233 vhost_work_queue(dev
, &flush
.work
);
234 wait_for_completion(&flush
.wait_event
);
237 EXPORT_SYMBOL_GPL(vhost_work_flush
);
239 /* Flush any work that has been scheduled. When calling this, don't hold any
240 * locks that are also used by the callback. */
241 void vhost_poll_flush(struct vhost_poll
*poll
)
243 vhost_work_flush(poll
->dev
, &poll
->work
);
245 EXPORT_SYMBOL_GPL(vhost_poll_flush
);
247 void vhost_work_queue(struct vhost_dev
*dev
, struct vhost_work
*work
)
252 if (!test_and_set_bit(VHOST_WORK_QUEUED
, &work
->flags
)) {
253 /* We can only add the work to the list after we're
254 * sure it was not in the list.
257 llist_add(&work
->node
, &dev
->work_list
);
258 wake_up_process(dev
->worker
);
261 EXPORT_SYMBOL_GPL(vhost_work_queue
);
263 /* A lockless hint for busy polling code to exit the loop */
264 bool vhost_has_work(struct vhost_dev
*dev
)
266 return !llist_empty(&dev
->work_list
);
268 EXPORT_SYMBOL_GPL(vhost_has_work
);
270 void vhost_poll_queue(struct vhost_poll
*poll
)
272 vhost_work_queue(poll
->dev
, &poll
->work
);
274 EXPORT_SYMBOL_GPL(vhost_poll_queue
);
276 static void vhost_vq_reset(struct vhost_dev
*dev
,
277 struct vhost_virtqueue
*vq
)
283 vq
->last_avail_idx
= 0;
285 vq
->last_used_idx
= 0;
286 vq
->signalled_used
= 0;
287 vq
->signalled_used_valid
= false;
289 vq
->log_used
= false;
290 vq
->log_addr
= -1ull;
291 vq
->private_data
= NULL
;
292 vq
->acked_features
= 0;
294 vq
->error_ctx
= NULL
;
301 vhost_reset_is_le(vq
);
302 vhost_disable_cross_endian(vq
);
303 vq
->busyloop_timeout
= 0;
306 static int vhost_worker(void *data
)
308 struct vhost_dev
*dev
= data
;
309 struct vhost_work
*work
, *work_next
;
310 struct llist_node
*node
;
311 mm_segment_t oldfs
= get_fs();
317 /* mb paired w/ kthread_stop */
318 set_current_state(TASK_INTERRUPTIBLE
);
320 if (kthread_should_stop()) {
321 __set_current_state(TASK_RUNNING
);
325 node
= llist_del_all(&dev
->work_list
);
329 node
= llist_reverse_order(node
);
330 /* make sure flag is seen after deletion */
332 llist_for_each_entry_safe(work
, work_next
, node
, node
) {
333 clear_bit(VHOST_WORK_QUEUED
, &work
->flags
);
334 __set_current_state(TASK_RUNNING
);
345 static void vhost_vq_free_iovecs(struct vhost_virtqueue
*vq
)
355 /* Helper to allocate iovec buffers for all vqs. */
356 static long vhost_dev_alloc_iovecs(struct vhost_dev
*dev
)
358 struct vhost_virtqueue
*vq
;
361 for (i
= 0; i
< dev
->nvqs
; ++i
) {
363 vq
->indirect
= kmalloc(sizeof *vq
->indirect
* UIO_MAXIOV
,
365 vq
->log
= kmalloc(sizeof *vq
->log
* UIO_MAXIOV
, GFP_KERNEL
);
366 vq
->heads
= kmalloc(sizeof *vq
->heads
* UIO_MAXIOV
, GFP_KERNEL
);
367 if (!vq
->indirect
|| !vq
->log
|| !vq
->heads
)
374 vhost_vq_free_iovecs(dev
->vqs
[i
]);
378 static void vhost_dev_free_iovecs(struct vhost_dev
*dev
)
382 for (i
= 0; i
< dev
->nvqs
; ++i
)
383 vhost_vq_free_iovecs(dev
->vqs
[i
]);
386 void vhost_dev_init(struct vhost_dev
*dev
,
387 struct vhost_virtqueue
**vqs
, int nvqs
)
389 struct vhost_virtqueue
*vq
;
394 mutex_init(&dev
->mutex
);
396 dev
->log_file
= NULL
;
400 init_llist_head(&dev
->work_list
);
403 for (i
= 0; i
< dev
->nvqs
; ++i
) {
409 mutex_init(&vq
->mutex
);
410 vhost_vq_reset(dev
, vq
);
412 vhost_poll_init(&vq
->poll
, vq
->handle_kick
,
416 EXPORT_SYMBOL_GPL(vhost_dev_init
);
418 /* Caller should have device mutex */
419 long vhost_dev_check_owner(struct vhost_dev
*dev
)
421 /* Are you the owner? If not, I don't think you mean to do that */
422 return dev
->mm
== current
->mm
? 0 : -EPERM
;
424 EXPORT_SYMBOL_GPL(vhost_dev_check_owner
);
426 struct vhost_attach_cgroups_struct
{
427 struct vhost_work work
;
428 struct task_struct
*owner
;
432 static void vhost_attach_cgroups_work(struct vhost_work
*work
)
434 struct vhost_attach_cgroups_struct
*s
;
436 s
= container_of(work
, struct vhost_attach_cgroups_struct
, work
);
437 s
->ret
= cgroup_attach_task_all(s
->owner
, current
);
440 static int vhost_attach_cgroups(struct vhost_dev
*dev
)
442 struct vhost_attach_cgroups_struct attach
;
444 attach
.owner
= current
;
445 vhost_work_init(&attach
.work
, vhost_attach_cgroups_work
);
446 vhost_work_queue(dev
, &attach
.work
);
447 vhost_work_flush(dev
, &attach
.work
);
451 /* Caller should have device mutex */
452 bool vhost_dev_has_owner(struct vhost_dev
*dev
)
456 EXPORT_SYMBOL_GPL(vhost_dev_has_owner
);
458 /* Caller should have device mutex */
459 long vhost_dev_set_owner(struct vhost_dev
*dev
)
461 struct task_struct
*worker
;
464 /* Is there an owner already? */
465 if (vhost_dev_has_owner(dev
)) {
470 /* No owner, become one */
471 dev
->mm
= get_task_mm(current
);
472 worker
= kthread_create(vhost_worker
, dev
, "vhost-%d", current
->pid
);
473 if (IS_ERR(worker
)) {
474 err
= PTR_ERR(worker
);
478 dev
->worker
= worker
;
479 wake_up_process(worker
); /* avoid contributing to loadavg */
481 err
= vhost_attach_cgroups(dev
);
485 err
= vhost_dev_alloc_iovecs(dev
);
491 kthread_stop(worker
);
500 EXPORT_SYMBOL_GPL(vhost_dev_set_owner
);
502 struct vhost_memory
*vhost_dev_reset_owner_prepare(void)
504 return kmalloc(offsetof(struct vhost_memory
, regions
), GFP_KERNEL
);
506 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare
);
508 /* Caller should have device mutex */
509 void vhost_dev_reset_owner(struct vhost_dev
*dev
, struct vhost_memory
*memory
)
513 vhost_dev_cleanup(dev
, true);
515 /* Restore memory to default empty mapping. */
516 memory
->nregions
= 0;
517 dev
->memory
= memory
;
518 /* We don't need VQ locks below since vhost_dev_cleanup makes sure
519 * VQs aren't running.
521 for (i
= 0; i
< dev
->nvqs
; ++i
)
522 dev
->vqs
[i
]->memory
= memory
;
524 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner
);
526 void vhost_dev_stop(struct vhost_dev
*dev
)
530 for (i
= 0; i
< dev
->nvqs
; ++i
) {
531 if (dev
->vqs
[i
]->kick
&& dev
->vqs
[i
]->handle_kick
) {
532 vhost_poll_stop(&dev
->vqs
[i
]->poll
);
533 vhost_poll_flush(&dev
->vqs
[i
]->poll
);
537 EXPORT_SYMBOL_GPL(vhost_dev_stop
);
539 /* Caller should have device mutex if and only if locked is set */
540 void vhost_dev_cleanup(struct vhost_dev
*dev
, bool locked
)
544 for (i
= 0; i
< dev
->nvqs
; ++i
) {
545 if (dev
->vqs
[i
]->error_ctx
)
546 eventfd_ctx_put(dev
->vqs
[i
]->error_ctx
);
547 if (dev
->vqs
[i
]->error
)
548 fput(dev
->vqs
[i
]->error
);
549 if (dev
->vqs
[i
]->kick
)
550 fput(dev
->vqs
[i
]->kick
);
551 if (dev
->vqs
[i
]->call_ctx
)
552 eventfd_ctx_put(dev
->vqs
[i
]->call_ctx
);
553 if (dev
->vqs
[i
]->call
)
554 fput(dev
->vqs
[i
]->call
);
555 vhost_vq_reset(dev
, dev
->vqs
[i
]);
557 vhost_dev_free_iovecs(dev
);
559 eventfd_ctx_put(dev
->log_ctx
);
563 dev
->log_file
= NULL
;
564 /* No one will access memory at this point */
567 WARN_ON(!llist_empty(&dev
->work_list
));
569 kthread_stop(dev
->worker
);
576 EXPORT_SYMBOL_GPL(vhost_dev_cleanup
);
578 static int log_access_ok(void __user
*log_base
, u64 addr
, unsigned long sz
)
580 u64 a
= addr
/ VHOST_PAGE_SIZE
/ 8;
582 /* Make sure 64 bit math will not overflow. */
583 if (a
> ULONG_MAX
- (unsigned long)log_base
||
584 a
+ (unsigned long)log_base
> ULONG_MAX
)
587 return access_ok(VERIFY_WRITE
, log_base
+ a
,
588 (sz
+ VHOST_PAGE_SIZE
* 8 - 1) / VHOST_PAGE_SIZE
/ 8);
591 /* Caller should have vq mutex and device mutex. */
592 static int vq_memory_access_ok(void __user
*log_base
, struct vhost_memory
*mem
,
600 for (i
= 0; i
< mem
->nregions
; ++i
) {
601 struct vhost_memory_region
*m
= mem
->regions
+ i
;
602 unsigned long a
= m
->userspace_addr
;
603 if (m
->memory_size
> ULONG_MAX
)
605 else if (!access_ok(VERIFY_WRITE
, (void __user
*)a
,
608 else if (log_all
&& !log_access_ok(log_base
,
616 /* Can we switch to this memory table? */
617 /* Caller should have device mutex but not vq mutex */
618 static int memory_access_ok(struct vhost_dev
*d
, struct vhost_memory
*mem
,
623 for (i
= 0; i
< d
->nvqs
; ++i
) {
627 mutex_lock(&d
->vqs
[i
]->mutex
);
628 log
= log_all
|| vhost_has_feature(d
->vqs
[i
], VHOST_F_LOG_ALL
);
629 /* If ring is inactive, will check when it's enabled. */
630 if (d
->vqs
[i
]->private_data
)
631 ok
= vq_memory_access_ok(d
->vqs
[i
]->log_base
, mem
, log
);
634 mutex_unlock(&d
->vqs
[i
]->mutex
);
641 #define vhost_put_user(vq, x, ptr) __put_user(x, ptr)
643 static int vhost_copy_to_user(struct vhost_virtqueue
*vq
, void *to
,
644 const void *from
, unsigned size
)
646 return __copy_to_user(to
, from
, size
);
649 #define vhost_get_user(vq, x, ptr) __get_user(x, ptr)
651 static int vhost_copy_from_user(struct vhost_virtqueue
*vq
, void *to
,
652 void *from
, unsigned size
)
654 return __copy_from_user(to
, from
, size
);
657 static int vq_access_ok(struct vhost_virtqueue
*vq
, unsigned int num
,
658 struct vring_desc __user
*desc
,
659 struct vring_avail __user
*avail
,
660 struct vring_used __user
*used
)
662 size_t s
= vhost_has_feature(vq
, VIRTIO_RING_F_EVENT_IDX
) ? 2 : 0;
663 return access_ok(VERIFY_READ
, desc
, num
* sizeof *desc
) &&
664 access_ok(VERIFY_READ
, avail
,
665 sizeof *avail
+ num
* sizeof *avail
->ring
+ s
) &&
666 access_ok(VERIFY_WRITE
, used
,
667 sizeof *used
+ num
* sizeof *used
->ring
+ s
);
670 /* Can we log writes? */
671 /* Caller should have device mutex but not vq mutex */
672 int vhost_log_access_ok(struct vhost_dev
*dev
)
674 return memory_access_ok(dev
, dev
->memory
, 1);
676 EXPORT_SYMBOL_GPL(vhost_log_access_ok
);
678 /* Verify access for write logging. */
679 /* Caller should have vq mutex and device mutex */
680 static int vq_log_access_ok(struct vhost_virtqueue
*vq
,
681 void __user
*log_base
)
683 size_t s
= vhost_has_feature(vq
, VIRTIO_RING_F_EVENT_IDX
) ? 2 : 0;
685 return vq_memory_access_ok(log_base
, vq
->memory
,
686 vhost_has_feature(vq
, VHOST_F_LOG_ALL
)) &&
687 (!vq
->log_used
|| log_access_ok(log_base
, vq
->log_addr
,
689 vq
->num
* sizeof *vq
->used
->ring
+ s
));
692 /* Can we start vq? */
693 /* Caller should have vq mutex and device mutex */
694 int vhost_vq_access_ok(struct vhost_virtqueue
*vq
)
696 return vq_access_ok(vq
, vq
->num
, vq
->desc
, vq
->avail
, vq
->used
) &&
697 vq_log_access_ok(vq
, vq
->log_base
);
699 EXPORT_SYMBOL_GPL(vhost_vq_access_ok
);
701 static int vhost_memory_reg_sort_cmp(const void *p1
, const void *p2
)
703 const struct vhost_memory_region
*r1
= p1
, *r2
= p2
;
704 if (r1
->guest_phys_addr
< r2
->guest_phys_addr
)
706 if (r1
->guest_phys_addr
> r2
->guest_phys_addr
)
711 static void *vhost_kvzalloc(unsigned long size
)
713 void *n
= kzalloc(size
, GFP_KERNEL
| __GFP_NOWARN
| __GFP_REPEAT
);
720 static long vhost_set_memory(struct vhost_dev
*d
, struct vhost_memory __user
*m
)
722 struct vhost_memory mem
, *newmem
, *oldmem
;
723 unsigned long size
= offsetof(struct vhost_memory
, regions
);
726 if (copy_from_user(&mem
, m
, size
))
730 if (mem
.nregions
> max_mem_regions
)
732 newmem
= vhost_kvzalloc(size
+ mem
.nregions
* sizeof(*m
->regions
));
736 memcpy(newmem
, &mem
, size
);
737 if (copy_from_user(newmem
->regions
, m
->regions
,
738 mem
.nregions
* sizeof *m
->regions
)) {
742 sort(newmem
->regions
, newmem
->nregions
, sizeof(*newmem
->regions
),
743 vhost_memory_reg_sort_cmp
, NULL
);
745 if (!memory_access_ok(d
, newmem
, 0)) {
752 /* All memory accesses are done under some VQ mutex. */
753 for (i
= 0; i
< d
->nvqs
; ++i
) {
754 mutex_lock(&d
->vqs
[i
]->mutex
);
755 d
->vqs
[i
]->memory
= newmem
;
756 mutex_unlock(&d
->vqs
[i
]->mutex
);
762 long vhost_vring_ioctl(struct vhost_dev
*d
, int ioctl
, void __user
*argp
)
764 struct file
*eventfp
, *filep
= NULL
;
765 bool pollstart
= false, pollstop
= false;
766 struct eventfd_ctx
*ctx
= NULL
;
767 u32 __user
*idxp
= argp
;
768 struct vhost_virtqueue
*vq
;
769 struct vhost_vring_state s
;
770 struct vhost_vring_file f
;
771 struct vhost_vring_addr a
;
775 r
= get_user(idx
, idxp
);
783 mutex_lock(&vq
->mutex
);
786 case VHOST_SET_VRING_NUM
:
787 /* Resizing ring with an active backend?
788 * You don't want to do that. */
789 if (vq
->private_data
) {
793 if (copy_from_user(&s
, argp
, sizeof s
)) {
797 if (!s
.num
|| s
.num
> 0xffff || (s
.num
& (s
.num
- 1))) {
803 case VHOST_SET_VRING_BASE
:
804 /* Moving base with an active backend?
805 * You don't want to do that. */
806 if (vq
->private_data
) {
810 if (copy_from_user(&s
, argp
, sizeof s
)) {
814 if (s
.num
> 0xffff) {
818 vq
->last_avail_idx
= s
.num
;
819 /* Forget the cached index value. */
820 vq
->avail_idx
= vq
->last_avail_idx
;
822 case VHOST_GET_VRING_BASE
:
824 s
.num
= vq
->last_avail_idx
;
825 if (copy_to_user(argp
, &s
, sizeof s
))
828 case VHOST_SET_VRING_ADDR
:
829 if (copy_from_user(&a
, argp
, sizeof a
)) {
833 if (a
.flags
& ~(0x1 << VHOST_VRING_F_LOG
)) {
837 /* For 32bit, verify that the top 32bits of the user
838 data are set to zero. */
839 if ((u64
)(unsigned long)a
.desc_user_addr
!= a
.desc_user_addr
||
840 (u64
)(unsigned long)a
.used_user_addr
!= a
.used_user_addr
||
841 (u64
)(unsigned long)a
.avail_user_addr
!= a
.avail_user_addr
) {
846 /* Make sure it's safe to cast pointers to vring types. */
847 BUILD_BUG_ON(__alignof__
*vq
->avail
> VRING_AVAIL_ALIGN_SIZE
);
848 BUILD_BUG_ON(__alignof__
*vq
->used
> VRING_USED_ALIGN_SIZE
);
849 if ((a
.avail_user_addr
& (VRING_AVAIL_ALIGN_SIZE
- 1)) ||
850 (a
.used_user_addr
& (VRING_USED_ALIGN_SIZE
- 1)) ||
851 (a
.log_guest_addr
& (VRING_USED_ALIGN_SIZE
- 1))) {
856 /* We only verify access here if backend is configured.
857 * If it is not, we don't as size might not have been setup.
858 * We will verify when backend is configured. */
859 if (vq
->private_data
) {
860 if (!vq_access_ok(vq
, vq
->num
,
861 (void __user
*)(unsigned long)a
.desc_user_addr
,
862 (void __user
*)(unsigned long)a
.avail_user_addr
,
863 (void __user
*)(unsigned long)a
.used_user_addr
)) {
868 /* Also validate log access for used ring if enabled. */
869 if ((a
.flags
& (0x1 << VHOST_VRING_F_LOG
)) &&
870 !log_access_ok(vq
->log_base
, a
.log_guest_addr
,
872 vq
->num
* sizeof *vq
->used
->ring
)) {
878 vq
->log_used
= !!(a
.flags
& (0x1 << VHOST_VRING_F_LOG
));
879 vq
->desc
= (void __user
*)(unsigned long)a
.desc_user_addr
;
880 vq
->avail
= (void __user
*)(unsigned long)a
.avail_user_addr
;
881 vq
->log_addr
= a
.log_guest_addr
;
882 vq
->used
= (void __user
*)(unsigned long)a
.used_user_addr
;
884 case VHOST_SET_VRING_KICK
:
885 if (copy_from_user(&f
, argp
, sizeof f
)) {
889 eventfp
= f
.fd
== -1 ? NULL
: eventfd_fget(f
.fd
);
890 if (IS_ERR(eventfp
)) {
891 r
= PTR_ERR(eventfp
);
894 if (eventfp
!= vq
->kick
) {
895 pollstop
= (filep
= vq
->kick
) != NULL
;
896 pollstart
= (vq
->kick
= eventfp
) != NULL
;
900 case VHOST_SET_VRING_CALL
:
901 if (copy_from_user(&f
, argp
, sizeof f
)) {
905 eventfp
= f
.fd
== -1 ? NULL
: eventfd_fget(f
.fd
);
906 if (IS_ERR(eventfp
)) {
907 r
= PTR_ERR(eventfp
);
910 if (eventfp
!= vq
->call
) {
914 vq
->call_ctx
= eventfp
?
915 eventfd_ctx_fileget(eventfp
) : NULL
;
919 case VHOST_SET_VRING_ERR
:
920 if (copy_from_user(&f
, argp
, sizeof f
)) {
924 eventfp
= f
.fd
== -1 ? NULL
: eventfd_fget(f
.fd
);
925 if (IS_ERR(eventfp
)) {
926 r
= PTR_ERR(eventfp
);
929 if (eventfp
!= vq
->error
) {
933 vq
->error_ctx
= eventfp
?
934 eventfd_ctx_fileget(eventfp
) : NULL
;
938 case VHOST_SET_VRING_ENDIAN
:
939 r
= vhost_set_vring_endian(vq
, argp
);
941 case VHOST_GET_VRING_ENDIAN
:
942 r
= vhost_get_vring_endian(vq
, idx
, argp
);
944 case VHOST_SET_VRING_BUSYLOOP_TIMEOUT
:
945 if (copy_from_user(&s
, argp
, sizeof(s
))) {
949 vq
->busyloop_timeout
= s
.num
;
951 case VHOST_GET_VRING_BUSYLOOP_TIMEOUT
:
953 s
.num
= vq
->busyloop_timeout
;
954 if (copy_to_user(argp
, &s
, sizeof(s
)))
961 if (pollstop
&& vq
->handle_kick
)
962 vhost_poll_stop(&vq
->poll
);
965 eventfd_ctx_put(ctx
);
969 if (pollstart
&& vq
->handle_kick
)
970 r
= vhost_poll_start(&vq
->poll
, vq
->kick
);
972 mutex_unlock(&vq
->mutex
);
974 if (pollstop
&& vq
->handle_kick
)
975 vhost_poll_flush(&vq
->poll
);
978 EXPORT_SYMBOL_GPL(vhost_vring_ioctl
);
980 /* Caller must have device mutex */
981 long vhost_dev_ioctl(struct vhost_dev
*d
, unsigned int ioctl
, void __user
*argp
)
983 struct file
*eventfp
, *filep
= NULL
;
984 struct eventfd_ctx
*ctx
= NULL
;
989 /* If you are not the owner, you can become one */
990 if (ioctl
== VHOST_SET_OWNER
) {
991 r
= vhost_dev_set_owner(d
);
995 /* You must be the owner to do anything else */
996 r
= vhost_dev_check_owner(d
);
1001 case VHOST_SET_MEM_TABLE
:
1002 r
= vhost_set_memory(d
, argp
);
1004 case VHOST_SET_LOG_BASE
:
1005 if (copy_from_user(&p
, argp
, sizeof p
)) {
1009 if ((u64
)(unsigned long)p
!= p
) {
1013 for (i
= 0; i
< d
->nvqs
; ++i
) {
1014 struct vhost_virtqueue
*vq
;
1015 void __user
*base
= (void __user
*)(unsigned long)p
;
1017 mutex_lock(&vq
->mutex
);
1018 /* If ring is inactive, will check when it's enabled. */
1019 if (vq
->private_data
&& !vq_log_access_ok(vq
, base
))
1022 vq
->log_base
= base
;
1023 mutex_unlock(&vq
->mutex
);
1026 case VHOST_SET_LOG_FD
:
1027 r
= get_user(fd
, (int __user
*)argp
);
1030 eventfp
= fd
== -1 ? NULL
: eventfd_fget(fd
);
1031 if (IS_ERR(eventfp
)) {
1032 r
= PTR_ERR(eventfp
);
1035 if (eventfp
!= d
->log_file
) {
1036 filep
= d
->log_file
;
1037 d
->log_file
= eventfp
;
1039 d
->log_ctx
= eventfp
?
1040 eventfd_ctx_fileget(eventfp
) : NULL
;
1043 for (i
= 0; i
< d
->nvqs
; ++i
) {
1044 mutex_lock(&d
->vqs
[i
]->mutex
);
1045 d
->vqs
[i
]->log_ctx
= d
->log_ctx
;
1046 mutex_unlock(&d
->vqs
[i
]->mutex
);
1049 eventfd_ctx_put(ctx
);
1060 EXPORT_SYMBOL_GPL(vhost_dev_ioctl
);
1062 static const struct vhost_memory_region
*find_region(struct vhost_memory
*mem
,
1063 __u64 addr
, __u32 len
)
1065 const struct vhost_memory_region
*reg
;
1066 int start
= 0, end
= mem
->nregions
;
1068 while (start
< end
) {
1069 int slot
= start
+ (end
- start
) / 2;
1070 reg
= mem
->regions
+ slot
;
1071 if (addr
>= reg
->guest_phys_addr
)
1077 reg
= mem
->regions
+ start
;
1078 if (addr
>= reg
->guest_phys_addr
&&
1079 reg
->guest_phys_addr
+ reg
->memory_size
> addr
)
1084 /* TODO: This is really inefficient. We need something like get_user()
1085 * (instruction directly accesses the data, with an exception table entry
1086 * returning -EFAULT). See Documentation/x86/exception-tables.txt.
1088 static int set_bit_to_user(int nr
, void __user
*addr
)
1090 unsigned long log
= (unsigned long)addr
;
1093 int bit
= nr
+ (log
% PAGE_SIZE
) * 8;
1096 r
= get_user_pages_fast(log
, 1, 1, &page
);
1100 base
= kmap_atomic(page
);
1102 kunmap_atomic(base
);
1103 set_page_dirty_lock(page
);
1108 static int log_write(void __user
*log_base
,
1109 u64 write_address
, u64 write_length
)
1111 u64 write_page
= write_address
/ VHOST_PAGE_SIZE
;
1116 write_length
+= write_address
% VHOST_PAGE_SIZE
;
1118 u64 base
= (u64
)(unsigned long)log_base
;
1119 u64 log
= base
+ write_page
/ 8;
1120 int bit
= write_page
% 8;
1121 if ((u64
)(unsigned long)log
!= log
)
1123 r
= set_bit_to_user(bit
, (void __user
*)(unsigned long)log
);
1126 if (write_length
<= VHOST_PAGE_SIZE
)
1128 write_length
-= VHOST_PAGE_SIZE
;
1134 int vhost_log_write(struct vhost_virtqueue
*vq
, struct vhost_log
*log
,
1135 unsigned int log_num
, u64 len
)
1139 /* Make sure data written is seen before log. */
1141 for (i
= 0; i
< log_num
; ++i
) {
1142 u64 l
= min(log
[i
].len
, len
);
1143 r
= log_write(vq
->log_base
, log
[i
].addr
, l
);
1149 eventfd_signal(vq
->log_ctx
, 1);
1153 /* Length written exceeds what we have stored. This is a bug. */
1157 EXPORT_SYMBOL_GPL(vhost_log_write
);
1159 static int vhost_update_used_flags(struct vhost_virtqueue
*vq
)
1162 if (vhost_put_user(vq
, cpu_to_vhost16(vq
, vq
->used_flags
),
1163 &vq
->used
->flags
) < 0)
1165 if (unlikely(vq
->log_used
)) {
1166 /* Make sure the flag is seen before log. */
1168 /* Log used flag write. */
1169 used
= &vq
->used
->flags
;
1170 log_write(vq
->log_base
, vq
->log_addr
+
1171 (used
- (void __user
*)vq
->used
),
1172 sizeof vq
->used
->flags
);
1174 eventfd_signal(vq
->log_ctx
, 1);
1179 static int vhost_update_avail_event(struct vhost_virtqueue
*vq
, u16 avail_event
)
1181 if (vhost_put_user(vq
, cpu_to_vhost16(vq
, vq
->avail_idx
),
1182 vhost_avail_event(vq
)))
1184 if (unlikely(vq
->log_used
)) {
1186 /* Make sure the event is seen before log. */
1188 /* Log avail event write */
1189 used
= vhost_avail_event(vq
);
1190 log_write(vq
->log_base
, vq
->log_addr
+
1191 (used
- (void __user
*)vq
->used
),
1192 sizeof *vhost_avail_event(vq
));
1194 eventfd_signal(vq
->log_ctx
, 1);
1199 int vhost_vq_init_access(struct vhost_virtqueue
*vq
)
1201 __virtio16 last_used_idx
;
1203 bool is_le
= vq
->is_le
;
1205 if (!vq
->private_data
) {
1206 vhost_reset_is_le(vq
);
1210 vhost_init_is_le(vq
);
1212 r
= vhost_update_used_flags(vq
);
1215 vq
->signalled_used_valid
= false;
1216 if (!access_ok(VERIFY_READ
, &vq
->used
->idx
, sizeof vq
->used
->idx
)) {
1220 r
= vhost_get_user(vq
, last_used_idx
, &vq
->used
->idx
);
1223 vq
->last_used_idx
= vhost16_to_cpu(vq
, last_used_idx
);
1229 EXPORT_SYMBOL_GPL(vhost_vq_init_access
);
1231 static int translate_desc(struct vhost_virtqueue
*vq
, u64 addr
, u32 len
,
1232 struct iovec iov
[], int iov_size
)
1234 const struct vhost_memory_region
*reg
;
1235 struct vhost_memory
*mem
;
1241 while ((u64
)len
> s
) {
1243 if (unlikely(ret
>= iov_size
)) {
1247 reg
= find_region(mem
, addr
, len
);
1248 if (unlikely(!reg
)) {
1253 size
= reg
->memory_size
- addr
+ reg
->guest_phys_addr
;
1254 _iov
->iov_len
= min((u64
)len
- s
, size
);
1255 _iov
->iov_base
= (void __user
*)(unsigned long)
1256 (reg
->userspace_addr
+ addr
- reg
->guest_phys_addr
);
1265 /* Each buffer in the virtqueues is actually a chain of descriptors. This
1266 * function returns the next descriptor in the chain,
1267 * or -1U if we're at the end. */
1268 static unsigned next_desc(struct vhost_virtqueue
*vq
, struct vring_desc
*desc
)
1272 /* If this descriptor says it doesn't chain, we're done. */
1273 if (!(desc
->flags
& cpu_to_vhost16(vq
, VRING_DESC_F_NEXT
)))
1276 /* Check they're not leading us off end of descriptors. */
1277 next
= vhost16_to_cpu(vq
, desc
->next
);
1278 /* Make sure compiler knows to grab that: we don't want it changing! */
1279 /* We will use the result as an index in an array, so most
1280 * architectures only need a compiler barrier here. */
1281 read_barrier_depends();
1286 static int get_indirect(struct vhost_virtqueue
*vq
,
1287 struct iovec iov
[], unsigned int iov_size
,
1288 unsigned int *out_num
, unsigned int *in_num
,
1289 struct vhost_log
*log
, unsigned int *log_num
,
1290 struct vring_desc
*indirect
)
1292 struct vring_desc desc
;
1293 unsigned int i
= 0, count
, found
= 0;
1294 u32 len
= vhost32_to_cpu(vq
, indirect
->len
);
1295 struct iov_iter from
;
1299 if (unlikely(len
% sizeof desc
)) {
1300 vq_err(vq
, "Invalid length in indirect descriptor: "
1301 "len 0x%llx not multiple of 0x%zx\n",
1302 (unsigned long long)len
,
1307 ret
= translate_desc(vq
, vhost64_to_cpu(vq
, indirect
->addr
), len
, vq
->indirect
,
1309 if (unlikely(ret
< 0)) {
1310 vq_err(vq
, "Translation failure %d in indirect.\n", ret
);
1313 iov_iter_init(&from
, READ
, vq
->indirect
, ret
, len
);
1315 /* We will use the result as an address to read from, so most
1316 * architectures only need a compiler barrier here. */
1317 read_barrier_depends();
1319 count
= len
/ sizeof desc
;
1320 /* Buffers are chained via a 16 bit next field, so
1321 * we can have at most 2^16 of these. */
1322 if (unlikely(count
> USHRT_MAX
+ 1)) {
1323 vq_err(vq
, "Indirect buffer length too big: %d\n",
1329 unsigned iov_count
= *in_num
+ *out_num
;
1330 if (unlikely(++found
> count
)) {
1331 vq_err(vq
, "Loop detected: last one at %u "
1332 "indirect size %u\n",
1336 if (unlikely(copy_from_iter(&desc
, sizeof(desc
), &from
) !=
1338 vq_err(vq
, "Failed indirect descriptor: idx %d, %zx\n",
1339 i
, (size_t)vhost64_to_cpu(vq
, indirect
->addr
) + i
* sizeof desc
);
1342 if (unlikely(desc
.flags
& cpu_to_vhost16(vq
, VRING_DESC_F_INDIRECT
))) {
1343 vq_err(vq
, "Nested indirect descriptor: idx %d, %zx\n",
1344 i
, (size_t)vhost64_to_cpu(vq
, indirect
->addr
) + i
* sizeof desc
);
1348 ret
= translate_desc(vq
, vhost64_to_cpu(vq
, desc
.addr
),
1349 vhost32_to_cpu(vq
, desc
.len
), iov
+ iov_count
,
1350 iov_size
- iov_count
);
1351 if (unlikely(ret
< 0)) {
1352 vq_err(vq
, "Translation failure %d indirect idx %d\n",
1356 /* If this is an input descriptor, increment that count. */
1357 if (desc
.flags
& cpu_to_vhost16(vq
, VRING_DESC_F_WRITE
)) {
1359 if (unlikely(log
)) {
1360 log
[*log_num
].addr
= vhost64_to_cpu(vq
, desc
.addr
);
1361 log
[*log_num
].len
= vhost32_to_cpu(vq
, desc
.len
);
1365 /* If it's an output descriptor, they're all supposed
1366 * to come before any input descriptors. */
1367 if (unlikely(*in_num
)) {
1368 vq_err(vq
, "Indirect descriptor "
1369 "has out after in: idx %d\n", i
);
1374 } while ((i
= next_desc(vq
, &desc
)) != -1);
1378 /* This looks in the virtqueue and for the first available buffer, and converts
1379 * it to an iovec for convenient access. Since descriptors consist of some
1380 * number of output then some number of input descriptors, it's actually two
1381 * iovecs, but we pack them into one and note how many of each there were.
1383 * This function returns the descriptor number found, or vq->num (which is
1384 * never a valid descriptor number) if none was found. A negative code is
1385 * returned on error. */
1386 int vhost_get_vq_desc(struct vhost_virtqueue
*vq
,
1387 struct iovec iov
[], unsigned int iov_size
,
1388 unsigned int *out_num
, unsigned int *in_num
,
1389 struct vhost_log
*log
, unsigned int *log_num
)
1391 struct vring_desc desc
;
1392 unsigned int i
, head
, found
= 0;
1394 __virtio16 avail_idx
;
1395 __virtio16 ring_head
;
1398 /* Check it isn't doing very strange things with descriptor numbers. */
1399 last_avail_idx
= vq
->last_avail_idx
;
1400 if (unlikely(vhost_get_user(vq
, avail_idx
, &vq
->avail
->idx
))) {
1401 vq_err(vq
, "Failed to access avail idx at %p\n",
1405 vq
->avail_idx
= vhost16_to_cpu(vq
, avail_idx
);
1407 if (unlikely((u16
)(vq
->avail_idx
- last_avail_idx
) > vq
->num
)) {
1408 vq_err(vq
, "Guest moved used index from %u to %u",
1409 last_avail_idx
, vq
->avail_idx
);
1413 /* If there's nothing new since last we looked, return invalid. */
1414 if (vq
->avail_idx
== last_avail_idx
)
1417 /* Only get avail ring entries after they have been exposed by guest. */
1420 /* Grab the next descriptor number they're advertising, and increment
1421 * the index we've seen. */
1422 if (unlikely(vhost_get_user(vq
, ring_head
,
1423 &vq
->avail
->ring
[last_avail_idx
& (vq
->num
- 1)]))) {
1424 vq_err(vq
, "Failed to read head: idx %d address %p\n",
1426 &vq
->avail
->ring
[last_avail_idx
% vq
->num
]);
1430 head
= vhost16_to_cpu(vq
, ring_head
);
1432 /* If their number is silly, that's an error. */
1433 if (unlikely(head
>= vq
->num
)) {
1434 vq_err(vq
, "Guest says index %u > %u is available",
1439 /* When we start there are none of either input nor output. */
1440 *out_num
= *in_num
= 0;
1446 unsigned iov_count
= *in_num
+ *out_num
;
1447 if (unlikely(i
>= vq
->num
)) {
1448 vq_err(vq
, "Desc index is %u > %u, head = %u",
1452 if (unlikely(++found
> vq
->num
)) {
1453 vq_err(vq
, "Loop detected: last one at %u "
1454 "vq size %u head %u\n",
1458 ret
= vhost_copy_from_user(vq
, &desc
, vq
->desc
+ i
,
1460 if (unlikely(ret
)) {
1461 vq_err(vq
, "Failed to get descriptor: idx %d addr %p\n",
1465 if (desc
.flags
& cpu_to_vhost16(vq
, VRING_DESC_F_INDIRECT
)) {
1466 ret
= get_indirect(vq
, iov
, iov_size
,
1468 log
, log_num
, &desc
);
1469 if (unlikely(ret
< 0)) {
1470 vq_err(vq
, "Failure detected "
1471 "in indirect descriptor at idx %d\n", i
);
1477 ret
= translate_desc(vq
, vhost64_to_cpu(vq
, desc
.addr
),
1478 vhost32_to_cpu(vq
, desc
.len
), iov
+ iov_count
,
1479 iov_size
- iov_count
);
1480 if (unlikely(ret
< 0)) {
1481 vq_err(vq
, "Translation failure %d descriptor idx %d\n",
1485 if (desc
.flags
& cpu_to_vhost16(vq
, VRING_DESC_F_WRITE
)) {
1486 /* If this is an input descriptor,
1487 * increment that count. */
1489 if (unlikely(log
)) {
1490 log
[*log_num
].addr
= vhost64_to_cpu(vq
, desc
.addr
);
1491 log
[*log_num
].len
= vhost32_to_cpu(vq
, desc
.len
);
1495 /* If it's an output descriptor, they're all supposed
1496 * to come before any input descriptors. */
1497 if (unlikely(*in_num
)) {
1498 vq_err(vq
, "Descriptor has out after in: "
1504 } while ((i
= next_desc(vq
, &desc
)) != -1);
1506 /* On success, increment avail index. */
1507 vq
->last_avail_idx
++;
1509 /* Assume notifications from guest are disabled at this point,
1510 * if they aren't we would need to update avail_event index. */
1511 BUG_ON(!(vq
->used_flags
& VRING_USED_F_NO_NOTIFY
));
1514 EXPORT_SYMBOL_GPL(vhost_get_vq_desc
);
1516 /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
1517 void vhost_discard_vq_desc(struct vhost_virtqueue
*vq
, int n
)
1519 vq
->last_avail_idx
-= n
;
1521 EXPORT_SYMBOL_GPL(vhost_discard_vq_desc
);
1523 /* After we've used one of their buffers, we tell them about it. We'll then
1524 * want to notify the guest, using eventfd. */
1525 int vhost_add_used(struct vhost_virtqueue
*vq
, unsigned int head
, int len
)
1527 struct vring_used_elem heads
= {
1528 cpu_to_vhost32(vq
, head
),
1529 cpu_to_vhost32(vq
, len
)
1532 return vhost_add_used_n(vq
, &heads
, 1);
1534 EXPORT_SYMBOL_GPL(vhost_add_used
);
1536 static int __vhost_add_used_n(struct vhost_virtqueue
*vq
,
1537 struct vring_used_elem
*heads
,
1540 struct vring_used_elem __user
*used
;
1544 start
= vq
->last_used_idx
& (vq
->num
- 1);
1545 used
= vq
->used
->ring
+ start
;
1547 if (vhost_put_user(vq
, heads
[0].id
, &used
->id
)) {
1548 vq_err(vq
, "Failed to write used id");
1551 if (vhost_put_user(vq
, heads
[0].len
, &used
->len
)) {
1552 vq_err(vq
, "Failed to write used len");
1555 } else if (vhost_copy_to_user(vq
, used
, heads
, count
* sizeof *used
)) {
1556 vq_err(vq
, "Failed to write used");
1559 if (unlikely(vq
->log_used
)) {
1560 /* Make sure data is seen before log. */
1562 /* Log used ring entry write. */
1563 log_write(vq
->log_base
,
1565 ((void __user
*)used
- (void __user
*)vq
->used
),
1566 count
* sizeof *used
);
1568 old
= vq
->last_used_idx
;
1569 new = (vq
->last_used_idx
+= count
);
1570 /* If the driver never bothers to signal in a very long while,
1571 * used index might wrap around. If that happens, invalidate
1572 * signalled_used index we stored. TODO: make sure driver
1573 * signals at least once in 2^16 and remove this. */
1574 if (unlikely((u16
)(new - vq
->signalled_used
) < (u16
)(new - old
)))
1575 vq
->signalled_used_valid
= false;
1579 /* After we've used one of their buffers, we tell them about it. We'll then
1580 * want to notify the guest, using eventfd. */
1581 int vhost_add_used_n(struct vhost_virtqueue
*vq
, struct vring_used_elem
*heads
,
1586 start
= vq
->last_used_idx
& (vq
->num
- 1);
1587 n
= vq
->num
- start
;
1589 r
= __vhost_add_used_n(vq
, heads
, n
);
1595 r
= __vhost_add_used_n(vq
, heads
, count
);
1597 /* Make sure buffer is written before we update index. */
1599 if (vhost_put_user(vq
, cpu_to_vhost16(vq
, vq
->last_used_idx
),
1601 vq_err(vq
, "Failed to increment used idx");
1604 if (unlikely(vq
->log_used
)) {
1605 /* Log used index update. */
1606 log_write(vq
->log_base
,
1607 vq
->log_addr
+ offsetof(struct vring_used
, idx
),
1608 sizeof vq
->used
->idx
);
1610 eventfd_signal(vq
->log_ctx
, 1);
1614 EXPORT_SYMBOL_GPL(vhost_add_used_n
);
1616 static bool vhost_notify(struct vhost_dev
*dev
, struct vhost_virtqueue
*vq
)
1621 /* Flush out used index updates. This is paired
1622 * with the barrier that the Guest executes when enabling
1626 if (vhost_has_feature(vq
, VIRTIO_F_NOTIFY_ON_EMPTY
) &&
1627 unlikely(vq
->avail_idx
== vq
->last_avail_idx
))
1630 if (!vhost_has_feature(vq
, VIRTIO_RING_F_EVENT_IDX
)) {
1632 if (vhost_get_user(vq
, flags
, &vq
->avail
->flags
)) {
1633 vq_err(vq
, "Failed to get flags");
1636 return !(flags
& cpu_to_vhost16(vq
, VRING_AVAIL_F_NO_INTERRUPT
));
1638 old
= vq
->signalled_used
;
1639 v
= vq
->signalled_used_valid
;
1640 new = vq
->signalled_used
= vq
->last_used_idx
;
1641 vq
->signalled_used_valid
= true;
1646 if (vhost_get_user(vq
, event
, vhost_used_event(vq
))) {
1647 vq_err(vq
, "Failed to get used event idx");
1650 return vring_need_event(vhost16_to_cpu(vq
, event
), new, old
);
1653 /* This actually signals the guest, using eventfd. */
1654 void vhost_signal(struct vhost_dev
*dev
, struct vhost_virtqueue
*vq
)
1656 /* Signal the Guest tell them we used something up. */
1657 if (vq
->call_ctx
&& vhost_notify(dev
, vq
))
1658 eventfd_signal(vq
->call_ctx
, 1);
1660 EXPORT_SYMBOL_GPL(vhost_signal
);
1662 /* And here's the combo meal deal. Supersize me! */
1663 void vhost_add_used_and_signal(struct vhost_dev
*dev
,
1664 struct vhost_virtqueue
*vq
,
1665 unsigned int head
, int len
)
1667 vhost_add_used(vq
, head
, len
);
1668 vhost_signal(dev
, vq
);
1670 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal
);
1672 /* multi-buffer version of vhost_add_used_and_signal */
1673 void vhost_add_used_and_signal_n(struct vhost_dev
*dev
,
1674 struct vhost_virtqueue
*vq
,
1675 struct vring_used_elem
*heads
, unsigned count
)
1677 vhost_add_used_n(vq
, heads
, count
);
1678 vhost_signal(dev
, vq
);
1680 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n
);
1682 /* return true if we're sure that avaiable ring is empty */
1683 bool vhost_vq_avail_empty(struct vhost_dev
*dev
, struct vhost_virtqueue
*vq
)
1685 __virtio16 avail_idx
;
1688 r
= vhost_get_user(vq
, avail_idx
, &vq
->avail
->idx
);
1692 return vhost16_to_cpu(vq
, avail_idx
) == vq
->avail_idx
;
1694 EXPORT_SYMBOL_GPL(vhost_vq_avail_empty
);
1696 /* OK, now we need to know about added descriptors. */
1697 bool vhost_enable_notify(struct vhost_dev
*dev
, struct vhost_virtqueue
*vq
)
1699 __virtio16 avail_idx
;
1702 if (!(vq
->used_flags
& VRING_USED_F_NO_NOTIFY
))
1704 vq
->used_flags
&= ~VRING_USED_F_NO_NOTIFY
;
1705 if (!vhost_has_feature(vq
, VIRTIO_RING_F_EVENT_IDX
)) {
1706 r
= vhost_update_used_flags(vq
);
1708 vq_err(vq
, "Failed to enable notification at %p: %d\n",
1709 &vq
->used
->flags
, r
);
1713 r
= vhost_update_avail_event(vq
, vq
->avail_idx
);
1715 vq_err(vq
, "Failed to update avail event index at %p: %d\n",
1716 vhost_avail_event(vq
), r
);
1720 /* They could have slipped one in as we were doing that: make
1721 * sure it's written, then check again. */
1723 r
= vhost_get_user(vq
, avail_idx
, &vq
->avail
->idx
);
1725 vq_err(vq
, "Failed to check avail idx at %p: %d\n",
1726 &vq
->avail
->idx
, r
);
1730 return vhost16_to_cpu(vq
, avail_idx
) != vq
->avail_idx
;
1732 EXPORT_SYMBOL_GPL(vhost_enable_notify
);
1734 /* We don't need to be notified again. */
1735 void vhost_disable_notify(struct vhost_dev
*dev
, struct vhost_virtqueue
*vq
)
1739 if (vq
->used_flags
& VRING_USED_F_NO_NOTIFY
)
1741 vq
->used_flags
|= VRING_USED_F_NO_NOTIFY
;
1742 if (!vhost_has_feature(vq
, VIRTIO_RING_F_EVENT_IDX
)) {
1743 r
= vhost_update_used_flags(vq
);
1745 vq_err(vq
, "Failed to enable notification at %p: %d\n",
1746 &vq
->used
->flags
, r
);
1749 EXPORT_SYMBOL_GPL(vhost_disable_notify
);
1751 static int __init
vhost_init(void)
1756 static void __exit
vhost_exit(void)
1760 module_init(vhost_init
);
1761 module_exit(vhost_exit
);
1763 MODULE_VERSION("0.0.1");
1764 MODULE_LICENSE("GPL v2");
1765 MODULE_AUTHOR("Michael S. Tsirkin");
1766 MODULE_DESCRIPTION("Host kernel accelerator for virtio");