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");