1 /* Copyright (C) 2009 Red Hat, Inc.
2 * Author: Michael S. Tsirkin <mst@redhat.com>
4 * This work is licensed under the terms of the GNU GPL, version 2.
6 * virtio-net server in host kernel.
9 #include <linux/compat.h>
10 #include <linux/eventfd.h>
11 #include <linux/vhost.h>
12 #include <linux/virtio_net.h>
13 #include <linux/miscdevice.h>
14 #include <linux/module.h>
15 #include <linux/moduleparam.h>
16 #include <linux/mutex.h>
17 #include <linux/workqueue.h>
18 #include <linux/rcupdate.h>
19 #include <linux/file.h>
20 #include <linux/slab.h>
22 #include <linux/net.h>
23 #include <linux/if_packet.h>
24 #include <linux/if_arp.h>
25 #include <linux/if_tun.h>
26 #include <linux/if_macvlan.h>
27 #include <linux/if_vlan.h>
33 static int experimental_zcopytx
= 1;
34 module_param(experimental_zcopytx
, int, 0444);
35 MODULE_PARM_DESC(experimental_zcopytx
, "Enable Zero Copy TX;"
36 " 1 -Enable; 0 - Disable");
38 /* Max number of bytes transferred before requeueing the job.
39 * Using this limit prevents one virtqueue from starving others. */
40 #define VHOST_NET_WEIGHT 0x80000
42 /* MAX number of TX used buffers for outstanding zerocopy */
43 #define VHOST_MAX_PEND 128
44 #define VHOST_GOODCOPY_LEN 256
47 * For transmit, used buffer len is unused; we override it to track buffer
48 * status internally; used for zerocopy tx only.
50 /* Lower device DMA failed */
51 #define VHOST_DMA_FAILED_LEN 3
52 /* Lower device DMA done */
53 #define VHOST_DMA_DONE_LEN 2
54 /* Lower device DMA in progress */
55 #define VHOST_DMA_IN_PROGRESS 1
57 #define VHOST_DMA_CLEAR_LEN 0
59 #define VHOST_DMA_IS_DONE(len) ((len) >= VHOST_DMA_DONE_LEN)
62 VHOST_NET_FEATURES
= VHOST_FEATURES
|
63 (1ULL << VHOST_NET_F_VIRTIO_NET_HDR
) |
64 (1ULL << VIRTIO_NET_F_MRG_RXBUF
),
73 struct vhost_net_ubuf_ref
{
75 wait_queue_head_t wait
;
76 struct vhost_virtqueue
*vq
;
79 struct vhost_net_virtqueue
{
80 struct vhost_virtqueue vq
;
81 /* hdr is used to store the virtio header.
82 * Since each iovec has >= 1 byte length, we never need more than
83 * header length entries to store the header. */
84 struct iovec hdr
[sizeof(struct virtio_net_hdr_mrg_rxbuf
)];
87 /* vhost zerocopy support fields below: */
88 /* last used idx for outstanding DMA zerocopy buffers */
90 /* first used idx for DMA done zerocopy buffers */
92 /* an array of userspace buffers info */
93 struct ubuf_info
*ubuf_info
;
94 /* Reference counting for outstanding ubufs.
95 * Protected by vq mutex. Writers must also take device mutex. */
96 struct vhost_net_ubuf_ref
*ubufs
;
100 struct vhost_dev dev
;
101 struct vhost_net_virtqueue vqs
[VHOST_NET_VQ_MAX
];
102 struct vhost_poll poll
[VHOST_NET_VQ_MAX
];
103 /* Number of TX recently submitted.
104 * Protected by tx vq lock. */
106 /* Number of times zerocopy TX recently failed.
107 * Protected by tx vq lock. */
108 unsigned tx_zcopy_err
;
109 /* Flush in progress. Protected by tx vq lock. */
113 static unsigned vhost_net_zcopy_mask __read_mostly
;
115 static void vhost_net_enable_zcopy(int vq
)
117 vhost_net_zcopy_mask
|= 0x1 << vq
;
120 static void vhost_net_zerocopy_done_signal(struct kref
*kref
)
122 struct vhost_net_ubuf_ref
*ubufs
;
124 ubufs
= container_of(kref
, struct vhost_net_ubuf_ref
, kref
);
125 wake_up(&ubufs
->wait
);
128 static struct vhost_net_ubuf_ref
*
129 vhost_net_ubuf_alloc(struct vhost_virtqueue
*vq
, bool zcopy
)
131 struct vhost_net_ubuf_ref
*ubufs
;
132 /* No zero copy backend? Nothing to count. */
135 ubufs
= kmalloc(sizeof(*ubufs
), GFP_KERNEL
);
137 return ERR_PTR(-ENOMEM
);
138 kref_init(&ubufs
->kref
);
139 init_waitqueue_head(&ubufs
->wait
);
144 static void vhost_net_ubuf_put(struct vhost_net_ubuf_ref
*ubufs
)
146 kref_put(&ubufs
->kref
, vhost_net_zerocopy_done_signal
);
149 static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref
*ubufs
)
151 kref_put(&ubufs
->kref
, vhost_net_zerocopy_done_signal
);
152 wait_event(ubufs
->wait
, !atomic_read(&ubufs
->kref
.refcount
));
155 static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref
*ubufs
)
157 vhost_net_ubuf_put_and_wait(ubufs
);
161 static void vhost_net_clear_ubuf_info(struct vhost_net
*n
)
165 for (i
= 0; i
< VHOST_NET_VQ_MAX
; ++i
) {
166 kfree(n
->vqs
[i
].ubuf_info
);
167 n
->vqs
[i
].ubuf_info
= NULL
;
171 int vhost_net_set_ubuf_info(struct vhost_net
*n
)
176 for (i
= 0; i
< VHOST_NET_VQ_MAX
; ++i
) {
177 zcopy
= vhost_net_zcopy_mask
& (0x1 << i
);
180 n
->vqs
[i
].ubuf_info
= kmalloc(sizeof(*n
->vqs
[i
].ubuf_info
) *
181 UIO_MAXIOV
, GFP_KERNEL
);
182 if (!n
->vqs
[i
].ubuf_info
)
188 vhost_net_clear_ubuf_info(n
);
192 void vhost_net_vq_reset(struct vhost_net
*n
)
196 vhost_net_clear_ubuf_info(n
);
198 for (i
= 0; i
< VHOST_NET_VQ_MAX
; i
++) {
199 n
->vqs
[i
].done_idx
= 0;
200 n
->vqs
[i
].upend_idx
= 0;
201 n
->vqs
[i
].ubufs
= NULL
;
202 n
->vqs
[i
].vhost_hlen
= 0;
203 n
->vqs
[i
].sock_hlen
= 0;
208 static void vhost_net_tx_packet(struct vhost_net
*net
)
211 if (net
->tx_packets
< 1024)
214 net
->tx_zcopy_err
= 0;
217 static void vhost_net_tx_err(struct vhost_net
*net
)
222 static bool vhost_net_tx_select_zcopy(struct vhost_net
*net
)
224 /* TX flush waits for outstanding DMAs to be done.
225 * Don't start new DMAs.
227 return !net
->tx_flush
&&
228 net
->tx_packets
/ 64 >= net
->tx_zcopy_err
;
231 static bool vhost_sock_zcopy(struct socket
*sock
)
233 return unlikely(experimental_zcopytx
) &&
234 sock_flag(sock
->sk
, SOCK_ZEROCOPY
);
237 /* Pop first len bytes from iovec. Return number of segments used. */
238 static int move_iovec_hdr(struct iovec
*from
, struct iovec
*to
,
239 size_t len
, int iov_count
)
244 while (len
&& seg
< iov_count
) {
245 size
= min(from
->iov_len
, len
);
246 to
->iov_base
= from
->iov_base
;
248 from
->iov_len
-= size
;
249 from
->iov_base
+= size
;
257 /* Copy iovec entries for len bytes from iovec. */
258 static void copy_iovec_hdr(const struct iovec
*from
, struct iovec
*to
,
259 size_t len
, int iovcount
)
264 while (len
&& seg
< iovcount
) {
265 size
= min(from
->iov_len
, len
);
266 to
->iov_base
= from
->iov_base
;
275 /* In case of DMA done not in order in lower device driver for some reason.
276 * upend_idx is used to track end of used idx, done_idx is used to track head
277 * of used idx. Once lower device DMA done contiguously, we will signal KVM
280 static int vhost_zerocopy_signal_used(struct vhost_net
*net
,
281 struct vhost_virtqueue
*vq
)
283 struct vhost_net_virtqueue
*nvq
=
284 container_of(vq
, struct vhost_net_virtqueue
, vq
);
288 for (i
= nvq
->done_idx
; i
!= nvq
->upend_idx
; i
= (i
+ 1) % UIO_MAXIOV
) {
289 if (vq
->heads
[i
].len
== VHOST_DMA_FAILED_LEN
)
290 vhost_net_tx_err(net
);
291 if (VHOST_DMA_IS_DONE(vq
->heads
[i
].len
)) {
292 vq
->heads
[i
].len
= VHOST_DMA_CLEAR_LEN
;
293 vhost_add_used_and_signal(vq
->dev
, vq
,
304 static void vhost_zerocopy_callback(struct ubuf_info
*ubuf
, bool success
)
306 struct vhost_net_ubuf_ref
*ubufs
= ubuf
->ctx
;
307 struct vhost_virtqueue
*vq
= ubufs
->vq
;
308 int cnt
= atomic_read(&ubufs
->kref
.refcount
);
310 /* set len to mark this desc buffers done DMA */
311 vq
->heads
[ubuf
->desc
].len
= success
?
312 VHOST_DMA_DONE_LEN
: VHOST_DMA_FAILED_LEN
;
313 vhost_net_ubuf_put(ubufs
);
316 * Trigger polling thread if guest stopped submitting new buffers:
317 * in this case, the refcount after decrement will eventually reach 1
319 * We also trigger polling periodically after each 16 packets
320 * (the value 16 here is more or less arbitrary, it's tuned to trigger
321 * less than 10% of times).
323 if (cnt
<= 2 || !(cnt
% 16))
324 vhost_poll_queue(&vq
->poll
);
327 /* Expects to be always run from workqueue - which acts as
328 * read-size critical section for our kind of RCU. */
329 static void handle_tx(struct vhost_net
*net
)
331 struct vhost_net_virtqueue
*nvq
= &net
->vqs
[VHOST_NET_VQ_TX
];
332 struct vhost_virtqueue
*vq
= &nvq
->vq
;
335 struct msghdr msg
= {
341 .msg_flags
= MSG_DONTWAIT
,
343 size_t len
, total_len
= 0;
347 struct vhost_net_ubuf_ref
*uninitialized_var(ubufs
);
348 bool zcopy
, zcopy_used
;
350 /* TODO: check that we are running from vhost_worker? */
351 sock
= rcu_dereference_check(vq
->private_data
, 1);
355 mutex_lock(&vq
->mutex
);
356 vhost_disable_notify(&net
->dev
, vq
);
358 hdr_size
= nvq
->vhost_hlen
;
362 /* Release DMAs done buffers first */
364 vhost_zerocopy_signal_used(net
, vq
);
366 head
= vhost_get_vq_desc(&net
->dev
, vq
, vq
->iov
,
370 /* On error, stop handling until the next kick. */
371 if (unlikely(head
< 0))
373 /* Nothing new? Wait for eventfd to tell us they refilled. */
374 if (head
== vq
->num
) {
377 /* If more outstanding DMAs, queue the work.
378 * Handle upend_idx wrap around
380 num_pends
= likely(nvq
->upend_idx
>= nvq
->done_idx
) ?
381 (nvq
->upend_idx
- nvq
->done_idx
) :
382 (nvq
->upend_idx
+ UIO_MAXIOV
-
384 if (unlikely(num_pends
> VHOST_MAX_PEND
))
386 if (unlikely(vhost_enable_notify(&net
->dev
, vq
))) {
387 vhost_disable_notify(&net
->dev
, vq
);
393 vq_err(vq
, "Unexpected descriptor format for TX: "
394 "out %d, int %d\n", out
, in
);
397 /* Skip header. TODO: support TSO. */
398 s
= move_iovec_hdr(vq
->iov
, nvq
->hdr
, hdr_size
, out
);
399 msg
.msg_iovlen
= out
;
400 len
= iov_length(vq
->iov
, out
);
403 vq_err(vq
, "Unexpected header len for TX: "
404 "%zd expected %zd\n",
405 iov_length(nvq
->hdr
, s
), hdr_size
);
408 zcopy_used
= zcopy
&& (len
>= VHOST_GOODCOPY_LEN
||
409 nvq
->upend_idx
!= nvq
->done_idx
);
411 /* use msg_control to pass vhost zerocopy ubuf info to skb */
413 vq
->heads
[nvq
->upend_idx
].id
= head
;
414 if (!vhost_net_tx_select_zcopy(net
) ||
415 len
< VHOST_GOODCOPY_LEN
) {
416 /* copy don't need to wait for DMA done */
417 vq
->heads
[nvq
->upend_idx
].len
=
419 msg
.msg_control
= NULL
;
420 msg
.msg_controllen
= 0;
423 struct ubuf_info
*ubuf
;
424 ubuf
= nvq
->ubuf_info
+ nvq
->upend_idx
;
426 vq
->heads
[nvq
->upend_idx
].len
=
427 VHOST_DMA_IN_PROGRESS
;
428 ubuf
->callback
= vhost_zerocopy_callback
;
429 ubuf
->ctx
= nvq
->ubufs
;
430 ubuf
->desc
= nvq
->upend_idx
;
431 msg
.msg_control
= ubuf
;
432 msg
.msg_controllen
= sizeof(ubuf
);
434 kref_get(&ubufs
->kref
);
436 nvq
->upend_idx
= (nvq
->upend_idx
+ 1) % UIO_MAXIOV
;
438 msg
.msg_control
= NULL
;
439 /* TODO: Check specific error and bomb out unless ENOBUFS? */
440 err
= sock
->ops
->sendmsg(NULL
, sock
, &msg
, len
);
441 if (unlikely(err
< 0)) {
444 vhost_net_ubuf_put(ubufs
);
445 nvq
->upend_idx
= ((unsigned)nvq
->upend_idx
- 1)
448 vhost_discard_vq_desc(vq
, 1);
452 pr_debug("Truncated TX packet: "
453 " len %d != %zd\n", err
, len
);
455 vhost_add_used_and_signal(&net
->dev
, vq
, head
, 0);
457 vhost_zerocopy_signal_used(net
, vq
);
459 vhost_net_tx_packet(net
);
460 if (unlikely(total_len
>= VHOST_NET_WEIGHT
)) {
461 vhost_poll_queue(&vq
->poll
);
466 mutex_unlock(&vq
->mutex
);
469 static int peek_head_len(struct sock
*sk
)
471 struct sk_buff
*head
;
475 spin_lock_irqsave(&sk
->sk_receive_queue
.lock
, flags
);
476 head
= skb_peek(&sk
->sk_receive_queue
);
479 if (vlan_tx_tag_present(head
))
483 spin_unlock_irqrestore(&sk
->sk_receive_queue
.lock
, flags
);
487 /* This is a multi-buffer version of vhost_get_desc, that works if
488 * vq has read descriptors only.
489 * @vq - the relevant virtqueue
490 * @datalen - data length we'll be reading
491 * @iovcount - returned count of io vectors we fill
493 * @log_num - log offset
494 * @quota - headcount quota, 1 for big buffer
495 * returns number of buffer heads allocated, negative on error
497 static int get_rx_bufs(struct vhost_virtqueue
*vq
,
498 struct vring_used_elem
*heads
,
501 struct vhost_log
*log
,
505 unsigned int out
, in
;
511 while (datalen
> 0 && headcount
< quota
) {
512 if (unlikely(seg
>= UIO_MAXIOV
)) {
516 r
= vhost_get_vq_desc(vq
->dev
, vq
, vq
->iov
+ seg
,
517 ARRAY_SIZE(vq
->iov
) - seg
, &out
,
527 if (unlikely(out
|| in
<= 0)) {
528 vq_err(vq
, "unexpected descriptor format for RX: "
529 "out %d, in %d\n", out
, in
);
537 heads
[headcount
].id
= d
;
538 heads
[headcount
].len
= iov_length(vq
->iov
+ seg
, in
);
539 datalen
-= heads
[headcount
].len
;
543 heads
[headcount
- 1].len
+= datalen
;
549 if (unlikely(datalen
> 0)) {
555 vhost_discard_vq_desc(vq
, headcount
);
559 /* Expects to be always run from workqueue - which acts as
560 * read-size critical section for our kind of RCU. */
561 static void handle_rx(struct vhost_net
*net
)
563 struct vhost_net_virtqueue
*nvq
= &net
->vqs
[VHOST_NET_VQ_RX
];
564 struct vhost_virtqueue
*vq
= &nvq
->vq
;
565 unsigned uninitialized_var(in
), log
;
566 struct vhost_log
*vq_log
;
567 struct msghdr msg
= {
570 .msg_control
= NULL
, /* FIXME: get and handle RX aux data. */
573 .msg_flags
= MSG_DONTWAIT
,
575 struct virtio_net_hdr_mrg_rxbuf hdr
= {
577 .hdr
.gso_type
= VIRTIO_NET_HDR_GSO_NONE
579 size_t total_len
= 0;
582 size_t vhost_hlen
, sock_hlen
;
583 size_t vhost_len
, sock_len
;
584 /* TODO: check that we are running from vhost_worker? */
585 struct socket
*sock
= rcu_dereference_check(vq
->private_data
, 1);
590 mutex_lock(&vq
->mutex
);
591 vhost_disable_notify(&net
->dev
, vq
);
592 vhost_hlen
= nvq
->vhost_hlen
;
593 sock_hlen
= nvq
->sock_hlen
;
595 vq_log
= unlikely(vhost_has_feature(&net
->dev
, VHOST_F_LOG_ALL
)) ?
597 mergeable
= vhost_has_feature(&net
->dev
, VIRTIO_NET_F_MRG_RXBUF
);
599 while ((sock_len
= peek_head_len(sock
->sk
))) {
600 sock_len
+= sock_hlen
;
601 vhost_len
= sock_len
+ vhost_hlen
;
602 headcount
= get_rx_bufs(vq
, vq
->heads
, vhost_len
,
604 likely(mergeable
) ? UIO_MAXIOV
: 1);
605 /* On error, stop handling until the next kick. */
606 if (unlikely(headcount
< 0))
608 /* On overrun, truncate and discard */
609 if (unlikely(headcount
> UIO_MAXIOV
)) {
611 err
= sock
->ops
->recvmsg(NULL
, sock
, &msg
,
612 1, MSG_DONTWAIT
| MSG_TRUNC
);
613 pr_debug("Discarded rx packet: len %zd\n", sock_len
);
616 /* OK, now we need to know about added descriptors. */
618 if (unlikely(vhost_enable_notify(&net
->dev
, vq
))) {
619 /* They have slipped one in as we were
620 * doing that: check again. */
621 vhost_disable_notify(&net
->dev
, vq
);
624 /* Nothing new? Wait for eventfd to tell us
628 /* We don't need to be notified again. */
629 if (unlikely((vhost_hlen
)))
630 /* Skip header. TODO: support TSO. */
631 move_iovec_hdr(vq
->iov
, nvq
->hdr
, vhost_hlen
, in
);
633 /* Copy the header for use in VIRTIO_NET_F_MRG_RXBUF:
634 * needed because recvmsg can modify msg_iov. */
635 copy_iovec_hdr(vq
->iov
, nvq
->hdr
, sock_hlen
, in
);
637 err
= sock
->ops
->recvmsg(NULL
, sock
, &msg
,
638 sock_len
, MSG_DONTWAIT
| MSG_TRUNC
);
639 /* Userspace might have consumed the packet meanwhile:
640 * it's not supposed to do this usually, but might be hard
641 * to prevent. Discard data we got (if any) and keep going. */
642 if (unlikely(err
!= sock_len
)) {
643 pr_debug("Discarded rx packet: "
644 " len %d, expected %zd\n", err
, sock_len
);
645 vhost_discard_vq_desc(vq
, headcount
);
648 if (unlikely(vhost_hlen
) &&
649 memcpy_toiovecend(nvq
->hdr
, (unsigned char *)&hdr
, 0,
651 vq_err(vq
, "Unable to write vnet_hdr at addr %p\n",
655 /* TODO: Should check and handle checksum. */
656 if (likely(mergeable
) &&
657 memcpy_toiovecend(nvq
->hdr
, (unsigned char *)&headcount
,
658 offsetof(typeof(hdr
), num_buffers
),
659 sizeof hdr
.num_buffers
)) {
660 vq_err(vq
, "Failed num_buffers write");
661 vhost_discard_vq_desc(vq
, headcount
);
664 vhost_add_used_and_signal_n(&net
->dev
, vq
, vq
->heads
,
666 if (unlikely(vq_log
))
667 vhost_log_write(vq
, vq_log
, log
, vhost_len
);
668 total_len
+= vhost_len
;
669 if (unlikely(total_len
>= VHOST_NET_WEIGHT
)) {
670 vhost_poll_queue(&vq
->poll
);
675 mutex_unlock(&vq
->mutex
);
678 static void handle_tx_kick(struct vhost_work
*work
)
680 struct vhost_virtqueue
*vq
= container_of(work
, struct vhost_virtqueue
,
682 struct vhost_net
*net
= container_of(vq
->dev
, struct vhost_net
, dev
);
687 static void handle_rx_kick(struct vhost_work
*work
)
689 struct vhost_virtqueue
*vq
= container_of(work
, struct vhost_virtqueue
,
691 struct vhost_net
*net
= container_of(vq
->dev
, struct vhost_net
, dev
);
696 static void handle_tx_net(struct vhost_work
*work
)
698 struct vhost_net
*net
= container_of(work
, struct vhost_net
,
699 poll
[VHOST_NET_VQ_TX
].work
);
703 static void handle_rx_net(struct vhost_work
*work
)
705 struct vhost_net
*net
= container_of(work
, struct vhost_net
,
706 poll
[VHOST_NET_VQ_RX
].work
);
710 static int vhost_net_open(struct inode
*inode
, struct file
*f
)
712 struct vhost_net
*n
= kmalloc(sizeof *n
, GFP_KERNEL
);
713 struct vhost_dev
*dev
;
714 struct vhost_virtqueue
**vqs
;
719 vqs
= kmalloc(VHOST_NET_VQ_MAX
* sizeof(*vqs
), GFP_KERNEL
);
726 vqs
[VHOST_NET_VQ_TX
] = &n
->vqs
[VHOST_NET_VQ_TX
].vq
;
727 vqs
[VHOST_NET_VQ_RX
] = &n
->vqs
[VHOST_NET_VQ_RX
].vq
;
728 n
->vqs
[VHOST_NET_VQ_TX
].vq
.handle_kick
= handle_tx_kick
;
729 n
->vqs
[VHOST_NET_VQ_RX
].vq
.handle_kick
= handle_rx_kick
;
730 for (i
= 0; i
< VHOST_NET_VQ_MAX
; i
++) {
731 n
->vqs
[i
].ubufs
= NULL
;
732 n
->vqs
[i
].ubuf_info
= NULL
;
733 n
->vqs
[i
].upend_idx
= 0;
734 n
->vqs
[i
].done_idx
= 0;
735 n
->vqs
[i
].vhost_hlen
= 0;
736 n
->vqs
[i
].sock_hlen
= 0;
738 r
= vhost_dev_init(dev
, vqs
, VHOST_NET_VQ_MAX
);
745 vhost_poll_init(n
->poll
+ VHOST_NET_VQ_TX
, handle_tx_net
, POLLOUT
, dev
);
746 vhost_poll_init(n
->poll
+ VHOST_NET_VQ_RX
, handle_rx_net
, POLLIN
, dev
);
753 static void vhost_net_disable_vq(struct vhost_net
*n
,
754 struct vhost_virtqueue
*vq
)
756 struct vhost_net_virtqueue
*nvq
=
757 container_of(vq
, struct vhost_net_virtqueue
, vq
);
758 struct vhost_poll
*poll
= n
->poll
+ (nvq
- n
->vqs
);
759 if (!vq
->private_data
)
761 vhost_poll_stop(poll
);
764 static int vhost_net_enable_vq(struct vhost_net
*n
,
765 struct vhost_virtqueue
*vq
)
767 struct vhost_net_virtqueue
*nvq
=
768 container_of(vq
, struct vhost_net_virtqueue
, vq
);
769 struct vhost_poll
*poll
= n
->poll
+ (nvq
- n
->vqs
);
772 sock
= rcu_dereference_protected(vq
->private_data
,
773 lockdep_is_held(&vq
->mutex
));
777 return vhost_poll_start(poll
, sock
->file
);
780 static struct socket
*vhost_net_stop_vq(struct vhost_net
*n
,
781 struct vhost_virtqueue
*vq
)
785 mutex_lock(&vq
->mutex
);
786 sock
= rcu_dereference_protected(vq
->private_data
,
787 lockdep_is_held(&vq
->mutex
));
788 vhost_net_disable_vq(n
, vq
);
789 rcu_assign_pointer(vq
->private_data
, NULL
);
790 mutex_unlock(&vq
->mutex
);
794 static void vhost_net_stop(struct vhost_net
*n
, struct socket
**tx_sock
,
795 struct socket
**rx_sock
)
797 *tx_sock
= vhost_net_stop_vq(n
, &n
->vqs
[VHOST_NET_VQ_TX
].vq
);
798 *rx_sock
= vhost_net_stop_vq(n
, &n
->vqs
[VHOST_NET_VQ_RX
].vq
);
801 static void vhost_net_flush_vq(struct vhost_net
*n
, int index
)
803 vhost_poll_flush(n
->poll
+ index
);
804 vhost_poll_flush(&n
->vqs
[index
].vq
.poll
);
807 static void vhost_net_flush(struct vhost_net
*n
)
809 vhost_net_flush_vq(n
, VHOST_NET_VQ_TX
);
810 vhost_net_flush_vq(n
, VHOST_NET_VQ_RX
);
811 if (n
->vqs
[VHOST_NET_VQ_TX
].ubufs
) {
812 mutex_lock(&n
->vqs
[VHOST_NET_VQ_TX
].vq
.mutex
);
814 mutex_unlock(&n
->vqs
[VHOST_NET_VQ_TX
].vq
.mutex
);
815 /* Wait for all lower device DMAs done. */
816 vhost_net_ubuf_put_and_wait(n
->vqs
[VHOST_NET_VQ_TX
].ubufs
);
817 mutex_lock(&n
->vqs
[VHOST_NET_VQ_TX
].vq
.mutex
);
819 kref_init(&n
->vqs
[VHOST_NET_VQ_TX
].ubufs
->kref
);
820 mutex_unlock(&n
->vqs
[VHOST_NET_VQ_TX
].vq
.mutex
);
824 static int vhost_net_release(struct inode
*inode
, struct file
*f
)
826 struct vhost_net
*n
= f
->private_data
;
827 struct socket
*tx_sock
;
828 struct socket
*rx_sock
;
830 vhost_net_stop(n
, &tx_sock
, &rx_sock
);
832 vhost_dev_stop(&n
->dev
);
833 vhost_dev_cleanup(&n
->dev
, false);
834 vhost_net_vq_reset(n
);
839 /* We do an extra flush before freeing memory,
840 * since jobs can re-queue themselves. */
847 static struct socket
*get_raw_socket(int fd
)
850 struct sockaddr_ll sa
;
851 char buf
[MAX_ADDR_LEN
];
853 int uaddr_len
= sizeof uaddr
, r
;
854 struct socket
*sock
= sockfd_lookup(fd
, &r
);
857 return ERR_PTR(-ENOTSOCK
);
859 /* Parameter checking */
860 if (sock
->sk
->sk_type
!= SOCK_RAW
) {
861 r
= -ESOCKTNOSUPPORT
;
865 r
= sock
->ops
->getname(sock
, (struct sockaddr
*)&uaddr
.sa
,
870 if (uaddr
.sa
.sll_family
!= AF_PACKET
) {
880 static struct socket
*get_tap_socket(int fd
)
882 struct file
*file
= fget(fd
);
886 return ERR_PTR(-EBADF
);
887 sock
= tun_get_socket(file
);
890 sock
= macvtap_get_socket(file
);
896 static struct socket
*get_socket(int fd
)
900 /* special case to disable backend */
903 sock
= get_raw_socket(fd
);
906 sock
= get_tap_socket(fd
);
909 return ERR_PTR(-ENOTSOCK
);
912 static long vhost_net_set_backend(struct vhost_net
*n
, unsigned index
, int fd
)
914 struct socket
*sock
, *oldsock
;
915 struct vhost_virtqueue
*vq
;
916 struct vhost_net_virtqueue
*nvq
;
917 struct vhost_net_ubuf_ref
*ubufs
, *oldubufs
= NULL
;
920 mutex_lock(&n
->dev
.mutex
);
921 r
= vhost_dev_check_owner(&n
->dev
);
925 if (index
>= VHOST_NET_VQ_MAX
) {
929 vq
= &n
->vqs
[index
].vq
;
930 nvq
= &n
->vqs
[index
];
931 mutex_lock(&vq
->mutex
);
933 /* Verify that ring has been setup correctly. */
934 if (!vhost_vq_access_ok(vq
)) {
938 sock
= get_socket(fd
);
944 /* start polling new socket */
945 oldsock
= rcu_dereference_protected(vq
->private_data
,
946 lockdep_is_held(&vq
->mutex
));
947 if (sock
!= oldsock
) {
948 ubufs
= vhost_net_ubuf_alloc(vq
,
949 sock
&& vhost_sock_zcopy(sock
));
955 vhost_net_disable_vq(n
, vq
);
956 rcu_assign_pointer(vq
->private_data
, sock
);
957 r
= vhost_init_used(vq
);
960 r
= vhost_net_enable_vq(n
, vq
);
964 oldubufs
= nvq
->ubufs
;
972 mutex_unlock(&vq
->mutex
);
975 vhost_net_ubuf_put_wait_and_free(oldubufs
);
976 mutex_lock(&vq
->mutex
);
977 vhost_zerocopy_signal_used(n
, vq
);
978 mutex_unlock(&vq
->mutex
);
982 vhost_net_flush_vq(n
, index
);
986 mutex_unlock(&n
->dev
.mutex
);
990 rcu_assign_pointer(vq
->private_data
, oldsock
);
991 vhost_net_enable_vq(n
, vq
);
993 vhost_net_ubuf_put_wait_and_free(ubufs
);
997 mutex_unlock(&vq
->mutex
);
999 mutex_unlock(&n
->dev
.mutex
);
1003 static long vhost_net_reset_owner(struct vhost_net
*n
)
1005 struct socket
*tx_sock
= NULL
;
1006 struct socket
*rx_sock
= NULL
;
1008 struct vhost_memory
*memory
;
1010 mutex_lock(&n
->dev
.mutex
);
1011 err
= vhost_dev_check_owner(&n
->dev
);
1014 memory
= vhost_dev_reset_owner_prepare();
1019 vhost_net_stop(n
, &tx_sock
, &rx_sock
);
1021 vhost_dev_reset_owner(&n
->dev
, memory
);
1022 vhost_net_vq_reset(n
);
1024 mutex_unlock(&n
->dev
.mutex
);
1026 fput(tx_sock
->file
);
1028 fput(rx_sock
->file
);
1032 static int vhost_net_set_features(struct vhost_net
*n
, u64 features
)
1034 size_t vhost_hlen
, sock_hlen
, hdr_len
;
1037 hdr_len
= (features
& (1 << VIRTIO_NET_F_MRG_RXBUF
)) ?
1038 sizeof(struct virtio_net_hdr_mrg_rxbuf
) :
1039 sizeof(struct virtio_net_hdr
);
1040 if (features
& (1 << VHOST_NET_F_VIRTIO_NET_HDR
)) {
1041 /* vhost provides vnet_hdr */
1042 vhost_hlen
= hdr_len
;
1045 /* socket provides vnet_hdr */
1047 sock_hlen
= hdr_len
;
1049 mutex_lock(&n
->dev
.mutex
);
1050 if ((features
& (1 << VHOST_F_LOG_ALL
)) &&
1051 !vhost_log_access_ok(&n
->dev
)) {
1052 mutex_unlock(&n
->dev
.mutex
);
1055 n
->dev
.acked_features
= features
;
1057 for (i
= 0; i
< VHOST_NET_VQ_MAX
; ++i
) {
1058 mutex_lock(&n
->vqs
[i
].vq
.mutex
);
1059 n
->vqs
[i
].vhost_hlen
= vhost_hlen
;
1060 n
->vqs
[i
].sock_hlen
= sock_hlen
;
1061 mutex_unlock(&n
->vqs
[i
].vq
.mutex
);
1064 mutex_unlock(&n
->dev
.mutex
);
1068 static long vhost_net_set_owner(struct vhost_net
*n
)
1072 mutex_lock(&n
->dev
.mutex
);
1073 if (vhost_dev_has_owner(&n
->dev
)) {
1077 r
= vhost_net_set_ubuf_info(n
);
1080 r
= vhost_dev_set_owner(&n
->dev
);
1082 vhost_net_clear_ubuf_info(n
);
1085 mutex_unlock(&n
->dev
.mutex
);
1089 static long vhost_net_ioctl(struct file
*f
, unsigned int ioctl
,
1092 struct vhost_net
*n
= f
->private_data
;
1093 void __user
*argp
= (void __user
*)arg
;
1094 u64 __user
*featurep
= argp
;
1095 struct vhost_vring_file backend
;
1100 case VHOST_NET_SET_BACKEND
:
1101 if (copy_from_user(&backend
, argp
, sizeof backend
))
1103 return vhost_net_set_backend(n
, backend
.index
, backend
.fd
);
1104 case VHOST_GET_FEATURES
:
1105 features
= VHOST_NET_FEATURES
;
1106 if (copy_to_user(featurep
, &features
, sizeof features
))
1109 case VHOST_SET_FEATURES
:
1110 if (copy_from_user(&features
, featurep
, sizeof features
))
1112 if (features
& ~VHOST_NET_FEATURES
)
1114 return vhost_net_set_features(n
, features
);
1115 case VHOST_RESET_OWNER
:
1116 return vhost_net_reset_owner(n
);
1117 case VHOST_SET_OWNER
:
1118 return vhost_net_set_owner(n
);
1120 mutex_lock(&n
->dev
.mutex
);
1121 r
= vhost_dev_ioctl(&n
->dev
, ioctl
, argp
);
1122 if (r
== -ENOIOCTLCMD
)
1123 r
= vhost_vring_ioctl(&n
->dev
, ioctl
, argp
);
1126 mutex_unlock(&n
->dev
.mutex
);
1131 #ifdef CONFIG_COMPAT
1132 static long vhost_net_compat_ioctl(struct file
*f
, unsigned int ioctl
,
1135 return vhost_net_ioctl(f
, ioctl
, (unsigned long)compat_ptr(arg
));
1139 static const struct file_operations vhost_net_fops
= {
1140 .owner
= THIS_MODULE
,
1141 .release
= vhost_net_release
,
1142 .unlocked_ioctl
= vhost_net_ioctl
,
1143 #ifdef CONFIG_COMPAT
1144 .compat_ioctl
= vhost_net_compat_ioctl
,
1146 .open
= vhost_net_open
,
1147 .llseek
= noop_llseek
,
1150 static struct miscdevice vhost_net_misc
= {
1151 .minor
= VHOST_NET_MINOR
,
1152 .name
= "vhost-net",
1153 .fops
= &vhost_net_fops
,
1156 static int vhost_net_init(void)
1158 if (experimental_zcopytx
)
1159 vhost_net_enable_zcopy(VHOST_NET_VQ_TX
);
1160 return misc_register(&vhost_net_misc
);
1162 module_init(vhost_net_init
);
1164 static void vhost_net_exit(void)
1166 misc_deregister(&vhost_net_misc
);
1168 module_exit(vhost_net_exit
);
1170 MODULE_VERSION("0.0.1");
1171 MODULE_LICENSE("GPL v2");
1172 MODULE_AUTHOR("Michael S. Tsirkin");
1173 MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
1174 MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR
);
1175 MODULE_ALIAS("devname:vhost-net");