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;
34 module_param(experimental_zcopytx, int, 0444);
35 MODULE_PARM_DESC(experimental_zcopytx, "Enable Experimental Zero Copy TX");
37 /* Max number of bytes transferred before requeueing the job.
38 * Using this limit prevents one virtqueue from starving others. */
39 #define VHOST_NET_WEIGHT 0x80000
41 /* MAX number of TX used buffers for outstanding zerocopy */
42 #define VHOST_MAX_PEND 128
43 #define VHOST_GOODCOPY_LEN 256
46 * For transmit, used buffer len is unused; we override it to track buffer
47 * status internally; used for zerocopy tx only.
49 /* Lower device DMA failed */
50 #define VHOST_DMA_FAILED_LEN 3
51 /* Lower device DMA done */
52 #define VHOST_DMA_DONE_LEN 2
53 /* Lower device DMA in progress */
54 #define VHOST_DMA_IN_PROGRESS 1
56 #define VHOST_DMA_CLEAR_LEN 0
58 #define VHOST_DMA_IS_DONE(len) ((len) >= VHOST_DMA_DONE_LEN)
66 enum vhost_net_poll_state {
67 VHOST_NET_POLL_DISABLED = 0,
68 VHOST_NET_POLL_STARTED = 1,
69 VHOST_NET_POLL_STOPPED = 2,
74 struct vhost_virtqueue vqs[VHOST_NET_VQ_MAX];
75 struct vhost_poll poll[VHOST_NET_VQ_MAX];
76 /* Tells us whether we are polling a socket for TX.
77 * We only do this when socket buffer fills up.
78 * Protected by tx vq lock. */
79 enum vhost_net_poll_state tx_poll_state;
80 /* Number of TX recently submitted.
81 * Protected by tx vq lock. */
83 /* Number of times zerocopy TX recently failed.
84 * Protected by tx vq lock. */
85 unsigned tx_zcopy_err;
86 /* Flush in progress. Protected by tx vq lock. */
90 static void vhost_net_tx_packet(struct vhost_net *net)
93 if (net->tx_packets < 1024)
96 net->tx_zcopy_err = 0;
99 static void vhost_net_tx_err(struct vhost_net *net)
104 static bool vhost_net_tx_select_zcopy(struct vhost_net *net)
106 /* TX flush waits for outstanding DMAs to be done.
107 * Don't start new DMAs.
109 return !net->tx_flush &&
110 net->tx_packets / 64 >= net->tx_zcopy_err;
113 static bool vhost_sock_zcopy(struct socket *sock)
115 return unlikely(experimental_zcopytx) &&
116 sock_flag(sock->sk, SOCK_ZEROCOPY);
119 /* Pop first len bytes from iovec. Return number of segments used. */
120 static int move_iovec_hdr(struct iovec *from, struct iovec *to,
121 size_t len, int iov_count)
126 while (len && seg < iov_count) {
127 size = min(from->iov_len, len);
128 to->iov_base = from->iov_base;
130 from->iov_len -= size;
131 from->iov_base += size;
139 /* Copy iovec entries for len bytes from iovec. */
140 static void copy_iovec_hdr(const struct iovec *from, struct iovec *to,
141 size_t len, int iovcount)
146 while (len && seg < iovcount) {
147 size = min(from->iov_len, len);
148 to->iov_base = from->iov_base;
157 /* Caller must have TX VQ lock */
158 static void tx_poll_stop(struct vhost_net *net)
160 if (likely(net->tx_poll_state != VHOST_NET_POLL_STARTED))
162 vhost_poll_stop(net->poll + VHOST_NET_VQ_TX);
163 net->tx_poll_state = VHOST_NET_POLL_STOPPED;
166 /* Caller must have TX VQ lock */
167 static void tx_poll_start(struct vhost_net *net, struct socket *sock)
169 if (unlikely(net->tx_poll_state != VHOST_NET_POLL_STOPPED))
171 vhost_poll_start(net->poll + VHOST_NET_VQ_TX, sock->file);
172 net->tx_poll_state = VHOST_NET_POLL_STARTED;
175 /* In case of DMA done not in order in lower device driver for some reason.
176 * upend_idx is used to track end of used idx, done_idx is used to track head
177 * of used idx. Once lower device DMA done contiguously, we will signal KVM
180 static int vhost_zerocopy_signal_used(struct vhost_net *net,
181 struct vhost_virtqueue *vq)
186 for (i = vq->done_idx; i != vq->upend_idx; i = (i + 1) % UIO_MAXIOV) {
187 if (vq->heads[i].len == VHOST_DMA_FAILED_LEN)
188 vhost_net_tx_err(net);
189 if (VHOST_DMA_IS_DONE(vq->heads[i].len)) {
190 vq->heads[i].len = VHOST_DMA_CLEAR_LEN;
191 vhost_add_used_and_signal(vq->dev, vq,
202 static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success)
204 struct vhost_ubuf_ref *ubufs = ubuf->ctx;
205 struct vhost_virtqueue *vq = ubufs->vq;
206 int cnt = atomic_read(&ubufs->kref.refcount);
209 * Trigger polling thread if guest stopped submitting new buffers:
210 * in this case, the refcount after decrement will eventually reach 1
212 * We also trigger polling periodically after each 16 packets
213 * (the value 16 here is more or less arbitrary, it's tuned to trigger
214 * less than 10% of times).
216 if (cnt <= 2 || !(cnt % 16))
217 vhost_poll_queue(&vq->poll);
218 /* set len to mark this desc buffers done DMA */
219 vq->heads[ubuf->desc].len = success ?
220 VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN;
221 vhost_ubuf_put(ubufs);
224 /* Expects to be always run from workqueue - which acts as
225 * read-size critical section for our kind of RCU. */
226 static void handle_tx(struct vhost_net *net)
228 struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_TX];
231 struct msghdr msg = {
237 .msg_flags = MSG_DONTWAIT,
239 size_t len, total_len = 0;
243 struct vhost_ubuf_ref *uninitialized_var(ubufs);
246 /* TODO: check that we are running from vhost_worker? */
247 sock = rcu_dereference_check(vq->private_data, 1);
251 wmem = atomic_read(&sock->sk->sk_wmem_alloc);
252 if (wmem >= sock->sk->sk_sndbuf) {
253 mutex_lock(&vq->mutex);
254 tx_poll_start(net, sock);
255 mutex_unlock(&vq->mutex);
259 mutex_lock(&vq->mutex);
260 vhost_disable_notify(&net->dev, vq);
262 if (wmem < sock->sk->sk_sndbuf / 2)
264 hdr_size = vq->vhost_hlen;
268 /* Release DMAs done buffers first */
270 vhost_zerocopy_signal_used(net, vq);
272 head = vhost_get_vq_desc(&net->dev, vq, vq->iov,
276 /* On error, stop handling until the next kick. */
277 if (unlikely(head < 0))
279 /* Nothing new? Wait for eventfd to tell us they refilled. */
280 if (head == vq->num) {
283 wmem = atomic_read(&sock->sk->sk_wmem_alloc);
284 if (wmem >= sock->sk->sk_sndbuf * 3 / 4) {
285 tx_poll_start(net, sock);
286 set_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
289 /* If more outstanding DMAs, queue the work.
290 * Handle upend_idx wrap around
292 num_pends = likely(vq->upend_idx >= vq->done_idx) ?
293 (vq->upend_idx - vq->done_idx) :
294 (vq->upend_idx + UIO_MAXIOV - vq->done_idx);
295 if (unlikely(num_pends > VHOST_MAX_PEND)) {
296 tx_poll_start(net, sock);
297 set_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
300 if (unlikely(vhost_enable_notify(&net->dev, vq))) {
301 vhost_disable_notify(&net->dev, vq);
307 vq_err(vq, "Unexpected descriptor format for TX: "
308 "out %d, int %d\n", out, in);
311 /* Skip header. TODO: support TSO. */
312 s = move_iovec_hdr(vq->iov, vq->hdr, hdr_size, out);
313 msg.msg_iovlen = out;
314 len = iov_length(vq->iov, out);
317 vq_err(vq, "Unexpected header len for TX: "
318 "%zd expected %zd\n",
319 iov_length(vq->hdr, s), hdr_size);
322 /* use msg_control to pass vhost zerocopy ubuf info to skb */
324 vq->heads[vq->upend_idx].id = head;
325 if (!vhost_net_tx_select_zcopy(net) ||
326 len < VHOST_GOODCOPY_LEN) {
327 /* copy don't need to wait for DMA done */
328 vq->heads[vq->upend_idx].len =
330 msg.msg_control = NULL;
331 msg.msg_controllen = 0;
334 struct ubuf_info *ubuf = &vq->ubuf_info[head];
336 vq->heads[vq->upend_idx].len =
337 VHOST_DMA_IN_PROGRESS;
338 ubuf->callback = vhost_zerocopy_callback;
339 ubuf->ctx = vq->ubufs;
340 ubuf->desc = vq->upend_idx;
341 msg.msg_control = ubuf;
342 msg.msg_controllen = sizeof(ubuf);
344 kref_get(&ubufs->kref);
346 vq->upend_idx = (vq->upend_idx + 1) % UIO_MAXIOV;
348 /* TODO: Check specific error and bomb out unless ENOBUFS? */
349 err = sock->ops->sendmsg(NULL, sock, &msg, len);
350 if (unlikely(err < 0)) {
353 vhost_ubuf_put(ubufs);
354 vq->upend_idx = ((unsigned)vq->upend_idx - 1) %
357 vhost_discard_vq_desc(vq, 1);
358 if (err == -EAGAIN || err == -ENOBUFS)
359 tx_poll_start(net, sock);
363 pr_debug("Truncated TX packet: "
364 " len %d != %zd\n", err, len);
366 vhost_add_used_and_signal(&net->dev, vq, head, 0);
368 vhost_zerocopy_signal_used(net, vq);
370 vhost_net_tx_packet(net);
371 if (unlikely(total_len >= VHOST_NET_WEIGHT)) {
372 vhost_poll_queue(&vq->poll);
377 mutex_unlock(&vq->mutex);
380 static int peek_head_len(struct sock *sk)
382 struct sk_buff *head;
386 spin_lock_irqsave(&sk->sk_receive_queue.lock, flags);
387 head = skb_peek(&sk->sk_receive_queue);
390 if (vlan_tx_tag_present(head))
394 spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags);
398 /* This is a multi-buffer version of vhost_get_desc, that works if
399 * vq has read descriptors only.
400 * @vq - the relevant virtqueue
401 * @datalen - data length we'll be reading
402 * @iovcount - returned count of io vectors we fill
404 * @log_num - log offset
405 * @quota - headcount quota, 1 for big buffer
406 * returns number of buffer heads allocated, negative on error
408 static int get_rx_bufs(struct vhost_virtqueue *vq,
409 struct vring_used_elem *heads,
412 struct vhost_log *log,
416 unsigned int out, in;
422 while (datalen > 0 && headcount < quota) {
423 if (unlikely(seg >= UIO_MAXIOV)) {
427 d = vhost_get_vq_desc(vq->dev, vq, vq->iov + seg,
428 ARRAY_SIZE(vq->iov) - seg, &out,
434 if (unlikely(out || in <= 0)) {
435 vq_err(vq, "unexpected descriptor format for RX: "
436 "out %d, in %d\n", out, in);
444 heads[headcount].id = d;
445 heads[headcount].len = iov_length(vq->iov + seg, in);
446 datalen -= heads[headcount].len;
450 heads[headcount - 1].len += datalen;
456 vhost_discard_vq_desc(vq, headcount);
460 /* Expects to be always run from workqueue - which acts as
461 * read-size critical section for our kind of RCU. */
462 static void handle_rx(struct vhost_net *net)
464 struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX];
465 unsigned uninitialized_var(in), log;
466 struct vhost_log *vq_log;
467 struct msghdr msg = {
470 .msg_control = NULL, /* FIXME: get and handle RX aux data. */
473 .msg_flags = MSG_DONTWAIT,
475 struct virtio_net_hdr_mrg_rxbuf hdr = {
477 .hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE
479 size_t total_len = 0;
482 size_t vhost_hlen, sock_hlen;
483 size_t vhost_len, sock_len;
484 /* TODO: check that we are running from vhost_worker? */
485 struct socket *sock = rcu_dereference_check(vq->private_data, 1);
490 mutex_lock(&vq->mutex);
491 vhost_disable_notify(&net->dev, vq);
492 vhost_hlen = vq->vhost_hlen;
493 sock_hlen = vq->sock_hlen;
495 vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ?
497 mergeable = vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF);
499 while ((sock_len = peek_head_len(sock->sk))) {
500 sock_len += sock_hlen;
501 vhost_len = sock_len + vhost_hlen;
502 headcount = get_rx_bufs(vq, vq->heads, vhost_len,
504 likely(mergeable) ? UIO_MAXIOV : 1);
505 /* On error, stop handling until the next kick. */
506 if (unlikely(headcount < 0))
508 /* OK, now we need to know about added descriptors. */
510 if (unlikely(vhost_enable_notify(&net->dev, vq))) {
511 /* They have slipped one in as we were
512 * doing that: check again. */
513 vhost_disable_notify(&net->dev, vq);
516 /* Nothing new? Wait for eventfd to tell us
520 /* We don't need to be notified again. */
521 if (unlikely((vhost_hlen)))
522 /* Skip header. TODO: support TSO. */
523 move_iovec_hdr(vq->iov, vq->hdr, vhost_hlen, in);
525 /* Copy the header for use in VIRTIO_NET_F_MRG_RXBUF:
526 * needed because recvmsg can modify msg_iov. */
527 copy_iovec_hdr(vq->iov, vq->hdr, sock_hlen, in);
529 err = sock->ops->recvmsg(NULL, sock, &msg,
530 sock_len, MSG_DONTWAIT | MSG_TRUNC);
531 /* Userspace might have consumed the packet meanwhile:
532 * it's not supposed to do this usually, but might be hard
533 * to prevent. Discard data we got (if any) and keep going. */
534 if (unlikely(err != sock_len)) {
535 pr_debug("Discarded rx packet: "
536 " len %d, expected %zd\n", err, sock_len);
537 vhost_discard_vq_desc(vq, headcount);
540 if (unlikely(vhost_hlen) &&
541 memcpy_toiovecend(vq->hdr, (unsigned char *)&hdr, 0,
543 vq_err(vq, "Unable to write vnet_hdr at addr %p\n",
547 /* TODO: Should check and handle checksum. */
548 if (likely(mergeable) &&
549 memcpy_toiovecend(vq->hdr, (unsigned char *)&headcount,
550 offsetof(typeof(hdr), num_buffers),
551 sizeof hdr.num_buffers)) {
552 vq_err(vq, "Failed num_buffers write");
553 vhost_discard_vq_desc(vq, headcount);
556 vhost_add_used_and_signal_n(&net->dev, vq, vq->heads,
558 if (unlikely(vq_log))
559 vhost_log_write(vq, vq_log, log, vhost_len);
560 total_len += vhost_len;
561 if (unlikely(total_len >= VHOST_NET_WEIGHT)) {
562 vhost_poll_queue(&vq->poll);
567 mutex_unlock(&vq->mutex);
570 static void handle_tx_kick(struct vhost_work *work)
572 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
574 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
579 static void handle_rx_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_tx_net(struct vhost_work *work)
590 struct vhost_net *net = container_of(work, struct vhost_net,
591 poll[VHOST_NET_VQ_TX].work);
595 static void handle_rx_net(struct vhost_work *work)
597 struct vhost_net *net = container_of(work, struct vhost_net,
598 poll[VHOST_NET_VQ_RX].work);
602 static int vhost_net_open(struct inode *inode, struct file *f)
604 struct vhost_net *n = kmalloc(sizeof *n, GFP_KERNEL);
605 struct vhost_dev *dev;
612 n->vqs[VHOST_NET_VQ_TX].handle_kick = handle_tx_kick;
613 n->vqs[VHOST_NET_VQ_RX].handle_kick = handle_rx_kick;
614 r = vhost_dev_init(dev, n->vqs, VHOST_NET_VQ_MAX);
620 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT, dev);
621 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN, dev);
622 n->tx_poll_state = VHOST_NET_POLL_DISABLED;
629 static void vhost_net_disable_vq(struct vhost_net *n,
630 struct vhost_virtqueue *vq)
632 if (!vq->private_data)
634 if (vq == n->vqs + VHOST_NET_VQ_TX) {
636 n->tx_poll_state = VHOST_NET_POLL_DISABLED;
638 vhost_poll_stop(n->poll + VHOST_NET_VQ_RX);
641 static void vhost_net_enable_vq(struct vhost_net *n,
642 struct vhost_virtqueue *vq)
646 sock = rcu_dereference_protected(vq->private_data,
647 lockdep_is_held(&vq->mutex));
650 if (vq == n->vqs + VHOST_NET_VQ_TX) {
651 n->tx_poll_state = VHOST_NET_POLL_STOPPED;
652 tx_poll_start(n, sock);
654 vhost_poll_start(n->poll + VHOST_NET_VQ_RX, sock->file);
657 static struct socket *vhost_net_stop_vq(struct vhost_net *n,
658 struct vhost_virtqueue *vq)
662 mutex_lock(&vq->mutex);
663 sock = rcu_dereference_protected(vq->private_data,
664 lockdep_is_held(&vq->mutex));
665 vhost_net_disable_vq(n, vq);
666 rcu_assign_pointer(vq->private_data, NULL);
667 mutex_unlock(&vq->mutex);
671 static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock,
672 struct socket **rx_sock)
674 *tx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_TX);
675 *rx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_RX);
678 static void vhost_net_flush_vq(struct vhost_net *n, int index)
680 vhost_poll_flush(n->poll + index);
681 vhost_poll_flush(&n->dev.vqs[index].poll);
684 static void vhost_net_flush(struct vhost_net *n)
686 vhost_net_flush_vq(n, VHOST_NET_VQ_TX);
687 vhost_net_flush_vq(n, VHOST_NET_VQ_RX);
688 if (n->dev.vqs[VHOST_NET_VQ_TX].ubufs) {
689 mutex_lock(&n->dev.vqs[VHOST_NET_VQ_TX].mutex);
691 mutex_unlock(&n->dev.vqs[VHOST_NET_VQ_TX].mutex);
692 /* Wait for all lower device DMAs done. */
693 vhost_ubuf_put_and_wait(n->dev.vqs[VHOST_NET_VQ_TX].ubufs);
694 mutex_lock(&n->dev.vqs[VHOST_NET_VQ_TX].mutex);
696 kref_init(&n->dev.vqs[VHOST_NET_VQ_TX].ubufs->kref);
697 mutex_unlock(&n->dev.vqs[VHOST_NET_VQ_TX].mutex);
701 static int vhost_net_release(struct inode *inode, struct file *f)
703 struct vhost_net *n = f->private_data;
704 struct socket *tx_sock;
705 struct socket *rx_sock;
707 vhost_net_stop(n, &tx_sock, &rx_sock);
709 vhost_dev_stop(&n->dev);
710 vhost_dev_cleanup(&n->dev, false);
715 /* We do an extra flush before freeing memory,
716 * since jobs can re-queue themselves. */
722 static struct socket *get_raw_socket(int fd)
725 struct sockaddr_ll sa;
726 char buf[MAX_ADDR_LEN];
728 int uaddr_len = sizeof uaddr, r;
729 struct socket *sock = sockfd_lookup(fd, &r);
732 return ERR_PTR(-ENOTSOCK);
734 /* Parameter checking */
735 if (sock->sk->sk_type != SOCK_RAW) {
736 r = -ESOCKTNOSUPPORT;
740 r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa,
745 if (uaddr.sa.sll_family != AF_PACKET) {
755 static struct socket *get_tap_socket(int fd)
757 struct file *file = fget(fd);
761 return ERR_PTR(-EBADF);
762 sock = tun_get_socket(file);
765 sock = macvtap_get_socket(file);
771 static struct socket *get_socket(int fd)
775 /* special case to disable backend */
778 sock = get_raw_socket(fd);
781 sock = get_tap_socket(fd);
784 return ERR_PTR(-ENOTSOCK);
787 static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
789 struct socket *sock, *oldsock;
790 struct vhost_virtqueue *vq;
791 struct vhost_ubuf_ref *ubufs, *oldubufs = NULL;
794 mutex_lock(&n->dev.mutex);
795 r = vhost_dev_check_owner(&n->dev);
799 if (index >= VHOST_NET_VQ_MAX) {
804 mutex_lock(&vq->mutex);
806 /* Verify that ring has been setup correctly. */
807 if (!vhost_vq_access_ok(vq)) {
811 sock = get_socket(fd);
817 /* start polling new socket */
818 oldsock = rcu_dereference_protected(vq->private_data,
819 lockdep_is_held(&vq->mutex));
820 if (sock != oldsock) {
821 ubufs = vhost_ubuf_alloc(vq, sock && vhost_sock_zcopy(sock));
826 oldubufs = vq->ubufs;
828 vhost_net_disable_vq(n, vq);
829 rcu_assign_pointer(vq->private_data, sock);
830 vhost_net_enable_vq(n, vq);
832 r = vhost_init_used(vq);
841 mutex_unlock(&vq->mutex);
844 vhost_ubuf_put_and_wait(oldubufs);
845 mutex_lock(&vq->mutex);
846 vhost_zerocopy_signal_used(n, vq);
847 mutex_unlock(&vq->mutex);
851 vhost_net_flush_vq(n, index);
855 mutex_unlock(&n->dev.mutex);
861 mutex_unlock(&vq->mutex);
863 mutex_unlock(&n->dev.mutex);
867 static long vhost_net_reset_owner(struct vhost_net *n)
869 struct socket *tx_sock = NULL;
870 struct socket *rx_sock = NULL;
873 mutex_lock(&n->dev.mutex);
874 err = vhost_dev_check_owner(&n->dev);
877 vhost_net_stop(n, &tx_sock, &rx_sock);
879 err = vhost_dev_reset_owner(&n->dev);
881 mutex_unlock(&n->dev.mutex);
889 static int vhost_net_set_features(struct vhost_net *n, u64 features)
891 size_t vhost_hlen, sock_hlen, hdr_len;
894 hdr_len = (features & (1 << VIRTIO_NET_F_MRG_RXBUF)) ?
895 sizeof(struct virtio_net_hdr_mrg_rxbuf) :
896 sizeof(struct virtio_net_hdr);
897 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) {
898 /* vhost provides vnet_hdr */
899 vhost_hlen = hdr_len;
902 /* socket provides vnet_hdr */
906 mutex_lock(&n->dev.mutex);
907 if ((features & (1 << VHOST_F_LOG_ALL)) &&
908 !vhost_log_access_ok(&n->dev)) {
909 mutex_unlock(&n->dev.mutex);
912 n->dev.acked_features = features;
914 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
915 mutex_lock(&n->vqs[i].mutex);
916 n->vqs[i].vhost_hlen = vhost_hlen;
917 n->vqs[i].sock_hlen = sock_hlen;
918 mutex_unlock(&n->vqs[i].mutex);
921 mutex_unlock(&n->dev.mutex);
925 static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
928 struct vhost_net *n = f->private_data;
929 void __user *argp = (void __user *)arg;
930 u64 __user *featurep = argp;
931 struct vhost_vring_file backend;
936 case VHOST_NET_SET_BACKEND:
937 if (copy_from_user(&backend, argp, sizeof backend))
939 return vhost_net_set_backend(n, backend.index, backend.fd);
940 case VHOST_GET_FEATURES:
941 features = VHOST_NET_FEATURES;
942 if (copy_to_user(featurep, &features, sizeof features))
945 case VHOST_SET_FEATURES:
946 if (copy_from_user(&features, featurep, sizeof features))
948 if (features & ~VHOST_NET_FEATURES)
950 return vhost_net_set_features(n, features);
951 case VHOST_RESET_OWNER:
952 return vhost_net_reset_owner(n);
954 mutex_lock(&n->dev.mutex);
955 r = vhost_dev_ioctl(&n->dev, ioctl, argp);
956 if (r == -ENOIOCTLCMD)
957 r = vhost_vring_ioctl(&n->dev, ioctl, argp);
960 mutex_unlock(&n->dev.mutex);
966 static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl,
969 return vhost_net_ioctl(f, ioctl, (unsigned long)compat_ptr(arg));
973 static const struct file_operations vhost_net_fops = {
974 .owner = THIS_MODULE,
975 .release = vhost_net_release,
976 .unlocked_ioctl = vhost_net_ioctl,
978 .compat_ioctl = vhost_net_compat_ioctl,
980 .open = vhost_net_open,
981 .llseek = noop_llseek,
984 static struct miscdevice vhost_net_misc = {
985 .minor = VHOST_NET_MINOR,
987 .fops = &vhost_net_fops,
990 static int vhost_net_init(void)
992 if (experimental_zcopytx)
993 vhost_enable_zcopy(VHOST_NET_VQ_TX);
994 return misc_register(&vhost_net_misc);
996 module_init(vhost_net_init);
998 static void vhost_net_exit(void)
1000 misc_deregister(&vhost_net_misc);
1002 module_exit(vhost_net_exit);
1004 MODULE_VERSION("0.0.1");
1005 MODULE_LICENSE("GPL v2");
1006 MODULE_AUTHOR("Michael S. Tsirkin");
1007 MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
1008 MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR);
1009 MODULE_ALIAS("devname:vhost-net");