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)
67 enum vhost_net_poll_state
{
68 VHOST_NET_POLL_DISABLED
= 0,
69 VHOST_NET_POLL_STARTED
= 1,
70 VHOST_NET_POLL_STOPPED
= 2,
75 struct vhost_virtqueue vqs
[VHOST_NET_VQ_MAX
];
76 struct vhost_poll poll
[VHOST_NET_VQ_MAX
];
77 /* Tells us whether we are polling a socket for TX.
78 * We only do this when socket buffer fills up.
79 * Protected by tx vq lock. */
80 enum vhost_net_poll_state tx_poll_state
;
81 /* Number of TX recently submitted.
82 * Protected by tx vq lock. */
84 /* Number of times zerocopy TX recently failed.
85 * Protected by tx vq lock. */
86 unsigned tx_zcopy_err
;
87 /* Flush in progress. Protected by tx vq lock. */
91 static void vhost_net_tx_packet(struct vhost_net
*net
)
94 if (net
->tx_packets
< 1024)
97 net
->tx_zcopy_err
= 0;
100 static void vhost_net_tx_err(struct vhost_net
*net
)
105 static bool vhost_net_tx_select_zcopy(struct vhost_net
*net
)
107 /* TX flush waits for outstanding DMAs to be done.
108 * Don't start new DMAs.
110 return !net
->tx_flush
&&
111 net
->tx_packets
/ 64 >= net
->tx_zcopy_err
;
114 static bool vhost_sock_zcopy(struct socket
*sock
)
116 return unlikely(experimental_zcopytx
) &&
117 sock_flag(sock
->sk
, SOCK_ZEROCOPY
);
120 /* Pop first len bytes from iovec. Return number of segments used. */
121 static int move_iovec_hdr(struct iovec
*from
, struct iovec
*to
,
122 size_t len
, int iov_count
)
127 while (len
&& seg
< iov_count
) {
128 size
= min(from
->iov_len
, len
);
129 to
->iov_base
= from
->iov_base
;
131 from
->iov_len
-= size
;
132 from
->iov_base
+= size
;
140 /* Copy iovec entries for len bytes from iovec. */
141 static void copy_iovec_hdr(const struct iovec
*from
, struct iovec
*to
,
142 size_t len
, int iovcount
)
147 while (len
&& seg
< iovcount
) {
148 size
= min(from
->iov_len
, len
);
149 to
->iov_base
= from
->iov_base
;
158 /* Caller must have TX VQ lock */
159 static void tx_poll_stop(struct vhost_net
*net
)
161 if (likely(net
->tx_poll_state
!= VHOST_NET_POLL_STARTED
))
163 vhost_poll_stop(net
->poll
+ VHOST_NET_VQ_TX
);
164 net
->tx_poll_state
= VHOST_NET_POLL_STOPPED
;
167 /* Caller must have TX VQ lock */
168 static int tx_poll_start(struct vhost_net
*net
, struct socket
*sock
)
172 if (unlikely(net
->tx_poll_state
!= VHOST_NET_POLL_STOPPED
))
174 ret
= vhost_poll_start(net
->poll
+ VHOST_NET_VQ_TX
, sock
->file
);
176 net
->tx_poll_state
= VHOST_NET_POLL_STARTED
;
180 /* In case of DMA done not in order in lower device driver for some reason.
181 * upend_idx is used to track end of used idx, done_idx is used to track head
182 * of used idx. Once lower device DMA done contiguously, we will signal KVM
185 static int vhost_zerocopy_signal_used(struct vhost_net
*net
,
186 struct vhost_virtqueue
*vq
)
191 for (i
= vq
->done_idx
; i
!= vq
->upend_idx
; i
= (i
+ 1) % UIO_MAXIOV
) {
192 if (vq
->heads
[i
].len
== VHOST_DMA_FAILED_LEN
)
193 vhost_net_tx_err(net
);
194 if (VHOST_DMA_IS_DONE(vq
->heads
[i
].len
)) {
195 vq
->heads
[i
].len
= VHOST_DMA_CLEAR_LEN
;
196 vhost_add_used_and_signal(vq
->dev
, vq
,
207 static void vhost_zerocopy_callback(struct ubuf_info
*ubuf
, bool success
)
209 struct vhost_ubuf_ref
*ubufs
= ubuf
->ctx
;
210 struct vhost_virtqueue
*vq
= ubufs
->vq
;
211 int cnt
= atomic_read(&ubufs
->kref
.refcount
);
214 * Trigger polling thread if guest stopped submitting new buffers:
215 * in this case, the refcount after decrement will eventually reach 1
217 * We also trigger polling periodically after each 16 packets
218 * (the value 16 here is more or less arbitrary, it's tuned to trigger
219 * less than 10% of times).
221 if (cnt
<= 2 || !(cnt
% 16))
222 vhost_poll_queue(&vq
->poll
);
223 /* set len to mark this desc buffers done DMA */
224 vq
->heads
[ubuf
->desc
].len
= success
?
225 VHOST_DMA_DONE_LEN
: VHOST_DMA_FAILED_LEN
;
226 vhost_ubuf_put(ubufs
);
229 /* Expects to be always run from workqueue - which acts as
230 * read-size critical section for our kind of RCU. */
231 static void handle_tx(struct vhost_net
*net
)
233 struct vhost_virtqueue
*vq
= &net
->dev
.vqs
[VHOST_NET_VQ_TX
];
236 struct msghdr msg
= {
242 .msg_flags
= MSG_DONTWAIT
,
244 size_t len
, total_len
= 0;
248 struct vhost_ubuf_ref
*uninitialized_var(ubufs
);
249 bool zcopy
, zcopy_used
;
251 /* TODO: check that we are running from vhost_worker? */
252 sock
= rcu_dereference_check(vq
->private_data
, 1);
256 wmem
= atomic_read(&sock
->sk
->sk_wmem_alloc
);
257 if (wmem
>= sock
->sk
->sk_sndbuf
) {
258 mutex_lock(&vq
->mutex
);
259 tx_poll_start(net
, sock
);
260 mutex_unlock(&vq
->mutex
);
264 mutex_lock(&vq
->mutex
);
265 vhost_disable_notify(&net
->dev
, vq
);
267 if (wmem
< sock
->sk
->sk_sndbuf
/ 2)
269 hdr_size
= vq
->vhost_hlen
;
273 /* Release DMAs done buffers first */
275 vhost_zerocopy_signal_used(net
, vq
);
277 head
= vhost_get_vq_desc(&net
->dev
, vq
, vq
->iov
,
281 /* On error, stop handling until the next kick. */
282 if (unlikely(head
< 0))
284 /* Nothing new? Wait for eventfd to tell us they refilled. */
285 if (head
== vq
->num
) {
288 wmem
= atomic_read(&sock
->sk
->sk_wmem_alloc
);
289 if (wmem
>= sock
->sk
->sk_sndbuf
* 3 / 4) {
290 tx_poll_start(net
, sock
);
291 set_bit(SOCK_ASYNC_NOSPACE
, &sock
->flags
);
294 /* If more outstanding DMAs, queue the work.
295 * Handle upend_idx wrap around
297 num_pends
= likely(vq
->upend_idx
>= vq
->done_idx
) ?
298 (vq
->upend_idx
- vq
->done_idx
) :
299 (vq
->upend_idx
+ UIO_MAXIOV
- vq
->done_idx
);
300 if (unlikely(num_pends
> VHOST_MAX_PEND
)) {
301 tx_poll_start(net
, sock
);
302 set_bit(SOCK_ASYNC_NOSPACE
, &sock
->flags
);
305 if (unlikely(vhost_enable_notify(&net
->dev
, vq
))) {
306 vhost_disable_notify(&net
->dev
, vq
);
312 vq_err(vq
, "Unexpected descriptor format for TX: "
313 "out %d, int %d\n", out
, in
);
316 /* Skip header. TODO: support TSO. */
317 s
= move_iovec_hdr(vq
->iov
, vq
->hdr
, hdr_size
, out
);
318 msg
.msg_iovlen
= out
;
319 len
= iov_length(vq
->iov
, out
);
322 vq_err(vq
, "Unexpected header len for TX: "
323 "%zd expected %zd\n",
324 iov_length(vq
->hdr
, s
), hdr_size
);
327 zcopy_used
= zcopy
&& (len
>= VHOST_GOODCOPY_LEN
||
328 vq
->upend_idx
!= vq
->done_idx
);
330 /* use msg_control to pass vhost zerocopy ubuf info to skb */
332 vq
->heads
[vq
->upend_idx
].id
= head
;
333 if (!vhost_net_tx_select_zcopy(net
) ||
334 len
< VHOST_GOODCOPY_LEN
) {
335 /* copy don't need to wait for DMA done */
336 vq
->heads
[vq
->upend_idx
].len
=
338 msg
.msg_control
= NULL
;
339 msg
.msg_controllen
= 0;
342 struct ubuf_info
*ubuf
;
343 ubuf
= vq
->ubuf_info
+ vq
->upend_idx
;
345 vq
->heads
[vq
->upend_idx
].len
=
346 VHOST_DMA_IN_PROGRESS
;
347 ubuf
->callback
= vhost_zerocopy_callback
;
348 ubuf
->ctx
= vq
->ubufs
;
349 ubuf
->desc
= vq
->upend_idx
;
350 msg
.msg_control
= ubuf
;
351 msg
.msg_controllen
= sizeof(ubuf
);
353 kref_get(&ubufs
->kref
);
355 vq
->upend_idx
= (vq
->upend_idx
+ 1) % UIO_MAXIOV
;
357 /* TODO: Check specific error and bomb out unless ENOBUFS? */
358 err
= sock
->ops
->sendmsg(NULL
, sock
, &msg
, len
);
359 if (unlikely(err
< 0)) {
362 vhost_ubuf_put(ubufs
);
363 vq
->upend_idx
= ((unsigned)vq
->upend_idx
- 1) %
366 vhost_discard_vq_desc(vq
, 1);
367 if (err
== -EAGAIN
|| err
== -ENOBUFS
)
368 tx_poll_start(net
, sock
);
372 pr_debug("Truncated TX packet: "
373 " len %d != %zd\n", err
, len
);
375 vhost_add_used_and_signal(&net
->dev
, vq
, head
, 0);
377 vhost_zerocopy_signal_used(net
, vq
);
379 vhost_net_tx_packet(net
);
380 if (unlikely(total_len
>= VHOST_NET_WEIGHT
)) {
381 vhost_poll_queue(&vq
->poll
);
386 mutex_unlock(&vq
->mutex
);
389 static int peek_head_len(struct sock
*sk
)
391 struct sk_buff
*head
;
395 spin_lock_irqsave(&sk
->sk_receive_queue
.lock
, flags
);
396 head
= skb_peek(&sk
->sk_receive_queue
);
399 if (vlan_tx_tag_present(head
))
403 spin_unlock_irqrestore(&sk
->sk_receive_queue
.lock
, flags
);
407 /* This is a multi-buffer version of vhost_get_desc, that works if
408 * vq has read descriptors only.
409 * @vq - the relevant virtqueue
410 * @datalen - data length we'll be reading
411 * @iovcount - returned count of io vectors we fill
413 * @log_num - log offset
414 * @quota - headcount quota, 1 for big buffer
415 * returns number of buffer heads allocated, negative on error
417 static int get_rx_bufs(struct vhost_virtqueue
*vq
,
418 struct vring_used_elem
*heads
,
421 struct vhost_log
*log
,
425 unsigned int out
, in
;
431 while (datalen
> 0 && headcount
< quota
) {
432 if (unlikely(seg
>= UIO_MAXIOV
)) {
436 d
= vhost_get_vq_desc(vq
->dev
, vq
, vq
->iov
+ seg
,
437 ARRAY_SIZE(vq
->iov
) - seg
, &out
,
443 if (unlikely(out
|| in
<= 0)) {
444 vq_err(vq
, "unexpected descriptor format for RX: "
445 "out %d, in %d\n", out
, in
);
453 heads
[headcount
].id
= d
;
454 heads
[headcount
].len
= iov_length(vq
->iov
+ seg
, in
);
455 datalen
-= heads
[headcount
].len
;
459 heads
[headcount
- 1].len
+= datalen
;
465 vhost_discard_vq_desc(vq
, headcount
);
469 /* Expects to be always run from workqueue - which acts as
470 * read-size critical section for our kind of RCU. */
471 static void handle_rx(struct vhost_net
*net
)
473 struct vhost_virtqueue
*vq
= &net
->dev
.vqs
[VHOST_NET_VQ_RX
];
474 unsigned uninitialized_var(in
), log
;
475 struct vhost_log
*vq_log
;
476 struct msghdr msg
= {
479 .msg_control
= NULL
, /* FIXME: get and handle RX aux data. */
482 .msg_flags
= MSG_DONTWAIT
,
484 struct virtio_net_hdr_mrg_rxbuf hdr
= {
486 .hdr
.gso_type
= VIRTIO_NET_HDR_GSO_NONE
488 size_t total_len
= 0;
491 size_t vhost_hlen
, sock_hlen
;
492 size_t vhost_len
, sock_len
;
493 /* TODO: check that we are running from vhost_worker? */
494 struct socket
*sock
= rcu_dereference_check(vq
->private_data
, 1);
499 mutex_lock(&vq
->mutex
);
500 vhost_disable_notify(&net
->dev
, vq
);
501 vhost_hlen
= vq
->vhost_hlen
;
502 sock_hlen
= vq
->sock_hlen
;
504 vq_log
= unlikely(vhost_has_feature(&net
->dev
, VHOST_F_LOG_ALL
)) ?
506 mergeable
= vhost_has_feature(&net
->dev
, VIRTIO_NET_F_MRG_RXBUF
);
508 while ((sock_len
= peek_head_len(sock
->sk
))) {
509 sock_len
+= sock_hlen
;
510 vhost_len
= sock_len
+ vhost_hlen
;
511 headcount
= get_rx_bufs(vq
, vq
->heads
, vhost_len
,
513 likely(mergeable
) ? UIO_MAXIOV
: 1);
514 /* On error, stop handling until the next kick. */
515 if (unlikely(headcount
< 0))
517 /* OK, now we need to know about added descriptors. */
519 if (unlikely(vhost_enable_notify(&net
->dev
, vq
))) {
520 /* They have slipped one in as we were
521 * doing that: check again. */
522 vhost_disable_notify(&net
->dev
, vq
);
525 /* Nothing new? Wait for eventfd to tell us
529 /* We don't need to be notified again. */
530 if (unlikely((vhost_hlen
)))
531 /* Skip header. TODO: support TSO. */
532 move_iovec_hdr(vq
->iov
, vq
->hdr
, vhost_hlen
, in
);
534 /* Copy the header for use in VIRTIO_NET_F_MRG_RXBUF:
535 * needed because recvmsg can modify msg_iov. */
536 copy_iovec_hdr(vq
->iov
, vq
->hdr
, sock_hlen
, in
);
538 err
= sock
->ops
->recvmsg(NULL
, sock
, &msg
,
539 sock_len
, MSG_DONTWAIT
| MSG_TRUNC
);
540 /* Userspace might have consumed the packet meanwhile:
541 * it's not supposed to do this usually, but might be hard
542 * to prevent. Discard data we got (if any) and keep going. */
543 if (unlikely(err
!= sock_len
)) {
544 pr_debug("Discarded rx packet: "
545 " len %d, expected %zd\n", err
, sock_len
);
546 vhost_discard_vq_desc(vq
, headcount
);
549 if (unlikely(vhost_hlen
) &&
550 memcpy_toiovecend(vq
->hdr
, (unsigned char *)&hdr
, 0,
552 vq_err(vq
, "Unable to write vnet_hdr at addr %p\n",
556 /* TODO: Should check and handle checksum. */
557 if (likely(mergeable
) &&
558 memcpy_toiovecend(vq
->hdr
, (unsigned char *)&headcount
,
559 offsetof(typeof(hdr
), num_buffers
),
560 sizeof hdr
.num_buffers
)) {
561 vq_err(vq
, "Failed num_buffers write");
562 vhost_discard_vq_desc(vq
, headcount
);
565 vhost_add_used_and_signal_n(&net
->dev
, vq
, vq
->heads
,
567 if (unlikely(vq_log
))
568 vhost_log_write(vq
, vq_log
, log
, vhost_len
);
569 total_len
+= vhost_len
;
570 if (unlikely(total_len
>= VHOST_NET_WEIGHT
)) {
571 vhost_poll_queue(&vq
->poll
);
576 mutex_unlock(&vq
->mutex
);
579 static void handle_tx_kick(struct vhost_work
*work
)
581 struct vhost_virtqueue
*vq
= container_of(work
, struct vhost_virtqueue
,
583 struct vhost_net
*net
= container_of(vq
->dev
, struct vhost_net
, dev
);
588 static void handle_rx_kick(struct vhost_work
*work
)
590 struct vhost_virtqueue
*vq
= container_of(work
, struct vhost_virtqueue
,
592 struct vhost_net
*net
= container_of(vq
->dev
, struct vhost_net
, dev
);
597 static void handle_tx_net(struct vhost_work
*work
)
599 struct vhost_net
*net
= container_of(work
, struct vhost_net
,
600 poll
[VHOST_NET_VQ_TX
].work
);
604 static void handle_rx_net(struct vhost_work
*work
)
606 struct vhost_net
*net
= container_of(work
, struct vhost_net
,
607 poll
[VHOST_NET_VQ_RX
].work
);
611 static int vhost_net_open(struct inode
*inode
, struct file
*f
)
613 struct vhost_net
*n
= kmalloc(sizeof *n
, GFP_KERNEL
);
614 struct vhost_dev
*dev
;
621 n
->vqs
[VHOST_NET_VQ_TX
].handle_kick
= handle_tx_kick
;
622 n
->vqs
[VHOST_NET_VQ_RX
].handle_kick
= handle_rx_kick
;
623 r
= vhost_dev_init(dev
, n
->vqs
, VHOST_NET_VQ_MAX
);
629 vhost_poll_init(n
->poll
+ VHOST_NET_VQ_TX
, handle_tx_net
, POLLOUT
, dev
);
630 vhost_poll_init(n
->poll
+ VHOST_NET_VQ_RX
, handle_rx_net
, POLLIN
, dev
);
631 n
->tx_poll_state
= VHOST_NET_POLL_DISABLED
;
638 static void vhost_net_disable_vq(struct vhost_net
*n
,
639 struct vhost_virtqueue
*vq
)
641 if (!vq
->private_data
)
643 if (vq
== n
->vqs
+ VHOST_NET_VQ_TX
) {
645 n
->tx_poll_state
= VHOST_NET_POLL_DISABLED
;
647 vhost_poll_stop(n
->poll
+ VHOST_NET_VQ_RX
);
650 static int vhost_net_enable_vq(struct vhost_net
*n
,
651 struct vhost_virtqueue
*vq
)
656 sock
= rcu_dereference_protected(vq
->private_data
,
657 lockdep_is_held(&vq
->mutex
));
660 if (vq
== n
->vqs
+ VHOST_NET_VQ_TX
) {
661 n
->tx_poll_state
= VHOST_NET_POLL_STOPPED
;
662 ret
= tx_poll_start(n
, sock
);
664 ret
= vhost_poll_start(n
->poll
+ VHOST_NET_VQ_RX
, sock
->file
);
669 static struct socket
*vhost_net_stop_vq(struct vhost_net
*n
,
670 struct vhost_virtqueue
*vq
)
674 mutex_lock(&vq
->mutex
);
675 sock
= rcu_dereference_protected(vq
->private_data
,
676 lockdep_is_held(&vq
->mutex
));
677 vhost_net_disable_vq(n
, vq
);
678 rcu_assign_pointer(vq
->private_data
, NULL
);
679 mutex_unlock(&vq
->mutex
);
683 static void vhost_net_stop(struct vhost_net
*n
, struct socket
**tx_sock
,
684 struct socket
**rx_sock
)
686 *tx_sock
= vhost_net_stop_vq(n
, n
->vqs
+ VHOST_NET_VQ_TX
);
687 *rx_sock
= vhost_net_stop_vq(n
, n
->vqs
+ VHOST_NET_VQ_RX
);
690 static void vhost_net_flush_vq(struct vhost_net
*n
, int index
)
692 vhost_poll_flush(n
->poll
+ index
);
693 vhost_poll_flush(&n
->dev
.vqs
[index
].poll
);
696 static void vhost_net_flush(struct vhost_net
*n
)
698 vhost_net_flush_vq(n
, VHOST_NET_VQ_TX
);
699 vhost_net_flush_vq(n
, VHOST_NET_VQ_RX
);
700 if (n
->dev
.vqs
[VHOST_NET_VQ_TX
].ubufs
) {
701 mutex_lock(&n
->dev
.vqs
[VHOST_NET_VQ_TX
].mutex
);
703 mutex_unlock(&n
->dev
.vqs
[VHOST_NET_VQ_TX
].mutex
);
704 /* Wait for all lower device DMAs done. */
705 vhost_ubuf_put_and_wait(n
->dev
.vqs
[VHOST_NET_VQ_TX
].ubufs
);
706 mutex_lock(&n
->dev
.vqs
[VHOST_NET_VQ_TX
].mutex
);
708 kref_init(&n
->dev
.vqs
[VHOST_NET_VQ_TX
].ubufs
->kref
);
709 mutex_unlock(&n
->dev
.vqs
[VHOST_NET_VQ_TX
].mutex
);
713 static int vhost_net_release(struct inode
*inode
, struct file
*f
)
715 struct vhost_net
*n
= f
->private_data
;
716 struct socket
*tx_sock
;
717 struct socket
*rx_sock
;
719 vhost_net_stop(n
, &tx_sock
, &rx_sock
);
721 vhost_dev_stop(&n
->dev
);
722 vhost_dev_cleanup(&n
->dev
, false);
727 /* We do an extra flush before freeing memory,
728 * since jobs can re-queue themselves. */
734 static struct socket
*get_raw_socket(int fd
)
737 struct sockaddr_ll sa
;
738 char buf
[MAX_ADDR_LEN
];
740 int uaddr_len
= sizeof uaddr
, r
;
741 struct socket
*sock
= sockfd_lookup(fd
, &r
);
744 return ERR_PTR(-ENOTSOCK
);
746 /* Parameter checking */
747 if (sock
->sk
->sk_type
!= SOCK_RAW
) {
748 r
= -ESOCKTNOSUPPORT
;
752 r
= sock
->ops
->getname(sock
, (struct sockaddr
*)&uaddr
.sa
,
757 if (uaddr
.sa
.sll_family
!= AF_PACKET
) {
767 static struct socket
*get_tap_socket(int fd
)
769 struct file
*file
= fget(fd
);
773 return ERR_PTR(-EBADF
);
774 sock
= tun_get_socket(file
);
777 sock
= macvtap_get_socket(file
);
783 static struct socket
*get_socket(int fd
)
787 /* special case to disable backend */
790 sock
= get_raw_socket(fd
);
793 sock
= get_tap_socket(fd
);
796 return ERR_PTR(-ENOTSOCK
);
799 static long vhost_net_set_backend(struct vhost_net
*n
, unsigned index
, int fd
)
801 struct socket
*sock
, *oldsock
;
802 struct vhost_virtqueue
*vq
;
803 struct vhost_ubuf_ref
*ubufs
, *oldubufs
= NULL
;
806 mutex_lock(&n
->dev
.mutex
);
807 r
= vhost_dev_check_owner(&n
->dev
);
811 if (index
>= VHOST_NET_VQ_MAX
) {
816 mutex_lock(&vq
->mutex
);
818 /* Verify that ring has been setup correctly. */
819 if (!vhost_vq_access_ok(vq
)) {
823 sock
= get_socket(fd
);
829 /* start polling new socket */
830 oldsock
= rcu_dereference_protected(vq
->private_data
,
831 lockdep_is_held(&vq
->mutex
));
832 if (sock
!= oldsock
) {
833 ubufs
= vhost_ubuf_alloc(vq
, sock
&& vhost_sock_zcopy(sock
));
839 vhost_net_disable_vq(n
, vq
);
840 rcu_assign_pointer(vq
->private_data
, sock
);
841 r
= vhost_init_used(vq
);
844 r
= vhost_net_enable_vq(n
, vq
);
848 oldubufs
= vq
->ubufs
;
856 mutex_unlock(&vq
->mutex
);
859 vhost_ubuf_put_and_wait(oldubufs
);
860 mutex_lock(&vq
->mutex
);
861 vhost_zerocopy_signal_used(n
, vq
);
862 mutex_unlock(&vq
->mutex
);
866 vhost_net_flush_vq(n
, index
);
870 mutex_unlock(&n
->dev
.mutex
);
874 rcu_assign_pointer(vq
->private_data
, oldsock
);
875 vhost_net_enable_vq(n
, vq
);
877 vhost_ubuf_put_and_wait(ubufs
);
881 mutex_unlock(&vq
->mutex
);
883 mutex_unlock(&n
->dev
.mutex
);
887 static long vhost_net_reset_owner(struct vhost_net
*n
)
889 struct socket
*tx_sock
= NULL
;
890 struct socket
*rx_sock
= NULL
;
893 mutex_lock(&n
->dev
.mutex
);
894 err
= vhost_dev_check_owner(&n
->dev
);
897 vhost_net_stop(n
, &tx_sock
, &rx_sock
);
899 err
= vhost_dev_reset_owner(&n
->dev
);
901 mutex_unlock(&n
->dev
.mutex
);
909 static int vhost_net_set_features(struct vhost_net
*n
, u64 features
)
911 size_t vhost_hlen
, sock_hlen
, hdr_len
;
914 hdr_len
= (features
& (1 << VIRTIO_NET_F_MRG_RXBUF
)) ?
915 sizeof(struct virtio_net_hdr_mrg_rxbuf
) :
916 sizeof(struct virtio_net_hdr
);
917 if (features
& (1 << VHOST_NET_F_VIRTIO_NET_HDR
)) {
918 /* vhost provides vnet_hdr */
919 vhost_hlen
= hdr_len
;
922 /* socket provides vnet_hdr */
926 mutex_lock(&n
->dev
.mutex
);
927 if ((features
& (1 << VHOST_F_LOG_ALL
)) &&
928 !vhost_log_access_ok(&n
->dev
)) {
929 mutex_unlock(&n
->dev
.mutex
);
932 n
->dev
.acked_features
= features
;
934 for (i
= 0; i
< VHOST_NET_VQ_MAX
; ++i
) {
935 mutex_lock(&n
->vqs
[i
].mutex
);
936 n
->vqs
[i
].vhost_hlen
= vhost_hlen
;
937 n
->vqs
[i
].sock_hlen
= sock_hlen
;
938 mutex_unlock(&n
->vqs
[i
].mutex
);
941 mutex_unlock(&n
->dev
.mutex
);
945 static long vhost_net_ioctl(struct file
*f
, unsigned int ioctl
,
948 struct vhost_net
*n
= f
->private_data
;
949 void __user
*argp
= (void __user
*)arg
;
950 u64 __user
*featurep
= argp
;
951 struct vhost_vring_file backend
;
956 case VHOST_NET_SET_BACKEND
:
957 if (copy_from_user(&backend
, argp
, sizeof backend
))
959 return vhost_net_set_backend(n
, backend
.index
, backend
.fd
);
960 case VHOST_GET_FEATURES
:
961 features
= VHOST_NET_FEATURES
;
962 if (copy_to_user(featurep
, &features
, sizeof features
))
965 case VHOST_SET_FEATURES
:
966 if (copy_from_user(&features
, featurep
, sizeof features
))
968 if (features
& ~VHOST_NET_FEATURES
)
970 return vhost_net_set_features(n
, features
);
971 case VHOST_RESET_OWNER
:
972 return vhost_net_reset_owner(n
);
974 mutex_lock(&n
->dev
.mutex
);
975 r
= vhost_dev_ioctl(&n
->dev
, ioctl
, argp
);
976 if (r
== -ENOIOCTLCMD
)
977 r
= vhost_vring_ioctl(&n
->dev
, ioctl
, argp
);
980 mutex_unlock(&n
->dev
.mutex
);
986 static long vhost_net_compat_ioctl(struct file
*f
, unsigned int ioctl
,
989 return vhost_net_ioctl(f
, ioctl
, (unsigned long)compat_ptr(arg
));
993 static const struct file_operations vhost_net_fops
= {
994 .owner
= THIS_MODULE
,
995 .release
= vhost_net_release
,
996 .unlocked_ioctl
= vhost_net_ioctl
,
998 .compat_ioctl
= vhost_net_compat_ioctl
,
1000 .open
= vhost_net_open
,
1001 .llseek
= noop_llseek
,
1004 static struct miscdevice vhost_net_misc
= {
1005 .minor
= VHOST_NET_MINOR
,
1006 .name
= "vhost-net",
1007 .fops
= &vhost_net_fops
,
1010 static int vhost_net_init(void)
1012 if (experimental_zcopytx
)
1013 vhost_enable_zcopy(VHOST_NET_VQ_TX
);
1014 return misc_register(&vhost_net_misc
);
1016 module_init(vhost_net_init
);
1018 static void vhost_net_exit(void)
1020 misc_deregister(&vhost_net_misc
);
1022 module_exit(vhost_net_exit
);
1024 MODULE_VERSION("0.0.1");
1025 MODULE_LICENSE("GPL v2");
1026 MODULE_AUTHOR("Michael S. Tsirkin");
1027 MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
1028 MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR
);
1029 MODULE_ALIAS("devname:vhost-net");