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1/* Copyright (C) 2009 Red Hat, Inc.
2 * Author: Michael S. Tsirkin <mst@redhat.com>
3 *
4 * This work is licensed under the terms of the GNU GPL, version 2.
5 *
6 * virtio-net server in host kernel.
7 */
8
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>
21
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
28#include <net/sock.h>
29
30#include "vhost.h"
31
32static int experimental_zcopytx;
33module_param(experimental_zcopytx, int, 0444);
34MODULE_PARM_DESC(experimental_zcopytx, "Enable Experimental Zero Copy TX");
35
36/* Max number of bytes transferred before requeueing the job.
37 * Using this limit prevents one virtqueue from starving others. */
38#define VHOST_NET_WEIGHT 0x80000
39
40/* MAX number of TX used buffers for outstanding zerocopy */
41#define VHOST_MAX_PEND 128
42#define VHOST_GOODCOPY_LEN 256
43
44enum {
45 VHOST_NET_VQ_RX = 0,
46 VHOST_NET_VQ_TX = 1,
47 VHOST_NET_VQ_MAX = 2,
48};
49
50enum vhost_net_poll_state {
51 VHOST_NET_POLL_DISABLED = 0,
52 VHOST_NET_POLL_STARTED = 1,
53 VHOST_NET_POLL_STOPPED = 2,
54};
55
56struct vhost_net {
57 struct vhost_dev dev;
58 struct vhost_virtqueue vqs[VHOST_NET_VQ_MAX];
59 struct vhost_poll poll[VHOST_NET_VQ_MAX];
60 /* Tells us whether we are polling a socket for TX.
61 * We only do this when socket buffer fills up.
62 * Protected by tx vq lock. */
63 enum vhost_net_poll_state tx_poll_state;
64};
65
66static bool vhost_sock_zcopy(struct socket *sock)
67{
68 return unlikely(experimental_zcopytx) &&
69 sock_flag(sock->sk, SOCK_ZEROCOPY);
70}
71
72/* Pop first len bytes from iovec. Return number of segments used. */
73static int move_iovec_hdr(struct iovec *from, struct iovec *to,
74 size_t len, int iov_count)
75{
76 int seg = 0;
77 size_t size;
78
79 while (len && seg < iov_count) {
80 size = min(from->iov_len, len);
81 to->iov_base = from->iov_base;
82 to->iov_len = size;
83 from->iov_len -= size;
84 from->iov_base += size;
85 len -= size;
86 ++from;
87 ++to;
88 ++seg;
89 }
90 return seg;
91}
92/* Copy iovec entries for len bytes from iovec. */
93static void copy_iovec_hdr(const struct iovec *from, struct iovec *to,
94 size_t len, int iovcount)
95{
96 int seg = 0;
97 size_t size;
98
99 while (len && seg < iovcount) {
100 size = min(from->iov_len, len);
101 to->iov_base = from->iov_base;
102 to->iov_len = size;
103 len -= size;
104 ++from;
105 ++to;
106 ++seg;
107 }
108}
109
110/* Caller must have TX VQ lock */
111static void tx_poll_stop(struct vhost_net *net)
112{
113 if (likely(net->tx_poll_state != VHOST_NET_POLL_STARTED))
114 return;
115 vhost_poll_stop(net->poll + VHOST_NET_VQ_TX);
116 net->tx_poll_state = VHOST_NET_POLL_STOPPED;
117}
118
119/* Caller must have TX VQ lock */
120static void tx_poll_start(struct vhost_net *net, struct socket *sock)
121{
122 if (unlikely(net->tx_poll_state != VHOST_NET_POLL_STOPPED))
123 return;
124 vhost_poll_start(net->poll + VHOST_NET_VQ_TX, sock->file);
125 net->tx_poll_state = VHOST_NET_POLL_STARTED;
126}
127
128/* Expects to be always run from workqueue - which acts as
129 * read-size critical section for our kind of RCU. */
130static void handle_tx(struct vhost_net *net)
131{
132 struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_TX];
133 unsigned out, in, s;
134 int head;
135 struct msghdr msg = {
136 .msg_name = NULL,
137 .msg_namelen = 0,
138 .msg_control = NULL,
139 .msg_controllen = 0,
140 .msg_iov = vq->iov,
141 .msg_flags = MSG_DONTWAIT,
142 };
143 size_t len, total_len = 0;
144 int err, wmem;
145 size_t hdr_size;
146 struct socket *sock;
147 struct vhost_ubuf_ref *uninitialized_var(ubufs);
148 bool zcopy;
149
150 /* TODO: check that we are running from vhost_worker? */
151 sock = rcu_dereference_check(vq->private_data, 1);
152 if (!sock)
153 return;
154
155 wmem = atomic_read(&sock->sk->sk_wmem_alloc);
156 if (wmem >= sock->sk->sk_sndbuf) {
157 mutex_lock(&vq->mutex);
158 tx_poll_start(net, sock);
159 mutex_unlock(&vq->mutex);
160 return;
161 }
162
163 mutex_lock(&vq->mutex);
164 vhost_disable_notify(&net->dev, vq);
165
166 if (wmem < sock->sk->sk_sndbuf / 2)
167 tx_poll_stop(net);
168 hdr_size = vq->vhost_hlen;
169 zcopy = vhost_sock_zcopy(sock);
170
171 for (;;) {
172 /* Release DMAs done buffers first */
173 if (zcopy)
174 vhost_zerocopy_signal_used(vq);
175
176 head = vhost_get_vq_desc(&net->dev, vq, vq->iov,
177 ARRAY_SIZE(vq->iov),
178 &out, &in,
179 NULL, NULL);
180 /* On error, stop handling until the next kick. */
181 if (unlikely(head < 0))
182 break;
183 /* Nothing new? Wait for eventfd to tell us they refilled. */
184 if (head == vq->num) {
185 int num_pends;
186
187 wmem = atomic_read(&sock->sk->sk_wmem_alloc);
188 if (wmem >= sock->sk->sk_sndbuf * 3 / 4) {
189 tx_poll_start(net, sock);
190 set_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
191 break;
192 }
193 /* If more outstanding DMAs, queue the work.
194 * Handle upend_idx wrap around
195 */
196 num_pends = likely(vq->upend_idx >= vq->done_idx) ?
197 (vq->upend_idx - vq->done_idx) :
198 (vq->upend_idx + UIO_MAXIOV - vq->done_idx);
199 if (unlikely(num_pends > VHOST_MAX_PEND)) {
200 tx_poll_start(net, sock);
201 set_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
202 break;
203 }
204 if (unlikely(vhost_enable_notify(&net->dev, vq))) {
205 vhost_disable_notify(&net->dev, vq);
206 continue;
207 }
208 break;
209 }
210 if (in) {
211 vq_err(vq, "Unexpected descriptor format for TX: "
212 "out %d, int %d\n", out, in);
213 break;
214 }
215 /* Skip header. TODO: support TSO. */
216 s = move_iovec_hdr(vq->iov, vq->hdr, hdr_size, out);
217 msg.msg_iovlen = out;
218 len = iov_length(vq->iov, out);
219 /* Sanity check */
220 if (!len) {
221 vq_err(vq, "Unexpected header len for TX: "
222 "%zd expected %zd\n",
223 iov_length(vq->hdr, s), hdr_size);
224 break;
225 }
226 /* use msg_control to pass vhost zerocopy ubuf info to skb */
227 if (zcopy) {
228 vq->heads[vq->upend_idx].id = head;
229 if (len < VHOST_GOODCOPY_LEN) {
230 /* copy don't need to wait for DMA done */
231 vq->heads[vq->upend_idx].len =
232 VHOST_DMA_DONE_LEN;
233 msg.msg_control = NULL;
234 msg.msg_controllen = 0;
235 ubufs = NULL;
236 } else {
237 struct ubuf_info *ubuf = &vq->ubuf_info[head];
238
239 vq->heads[vq->upend_idx].len = len;
240 ubuf->callback = vhost_zerocopy_callback;
241 ubuf->arg = vq->ubufs;
242 ubuf->desc = vq->upend_idx;
243 msg.msg_control = ubuf;
244 msg.msg_controllen = sizeof(ubuf);
245 ubufs = vq->ubufs;
246 kref_get(&ubufs->kref);
247 }
248 vq->upend_idx = (vq->upend_idx + 1) % UIO_MAXIOV;
249 }
250 /* TODO: Check specific error and bomb out unless ENOBUFS? */
251 err = sock->ops->sendmsg(NULL, sock, &msg, len);
252 if (unlikely(err < 0)) {
253 if (zcopy) {
254 if (ubufs)
255 vhost_ubuf_put(ubufs);
256 vq->upend_idx = ((unsigned)vq->upend_idx - 1) %
257 UIO_MAXIOV;
258 }
259 vhost_discard_vq_desc(vq, 1);
260 tx_poll_start(net, sock);
261 break;
262 }
263 if (err != len)
264 pr_debug("Truncated TX packet: "
265 " len %d != %zd\n", err, len);
266 if (!zcopy)
267 vhost_add_used_and_signal(&net->dev, vq, head, 0);
268 total_len += len;
269 if (unlikely(total_len >= VHOST_NET_WEIGHT)) {
270 vhost_poll_queue(&vq->poll);
271 break;
272 }
273 }
274
275 mutex_unlock(&vq->mutex);
276}
277
278static int peek_head_len(struct sock *sk)
279{
280 struct sk_buff *head;
281 int len = 0;
282 unsigned long flags;
283
284 spin_lock_irqsave(&sk->sk_receive_queue.lock, flags);
285 head = skb_peek(&sk->sk_receive_queue);
286 if (likely(head))
287 len = head->len;
288 spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags);
289 return len;
290}
291
292/* This is a multi-buffer version of vhost_get_desc, that works if
293 * vq has read descriptors only.
294 * @vq - the relevant virtqueue
295 * @datalen - data length we'll be reading
296 * @iovcount - returned count of io vectors we fill
297 * @log - vhost log
298 * @log_num - log offset
299 * @quota - headcount quota, 1 for big buffer
300 * returns number of buffer heads allocated, negative on error
301 */
302static int get_rx_bufs(struct vhost_virtqueue *vq,
303 struct vring_used_elem *heads,
304 int datalen,
305 unsigned *iovcount,
306 struct vhost_log *log,
307 unsigned *log_num,
308 unsigned int quota)
309{
310 unsigned int out, in;
311 int seg = 0;
312 int headcount = 0;
313 unsigned d;
314 int r, nlogs = 0;
315
316 while (datalen > 0 && headcount < quota) {
317 if (unlikely(seg >= UIO_MAXIOV)) {
318 r = -ENOBUFS;
319 goto err;
320 }
321 d = vhost_get_vq_desc(vq->dev, vq, vq->iov + seg,
322 ARRAY_SIZE(vq->iov) - seg, &out,
323 &in, log, log_num);
324 if (d == vq->num) {
325 r = 0;
326 goto err;
327 }
328 if (unlikely(out || in <= 0)) {
329 vq_err(vq, "unexpected descriptor format for RX: "
330 "out %d, in %d\n", out, in);
331 r = -EINVAL;
332 goto err;
333 }
334 if (unlikely(log)) {
335 nlogs += *log_num;
336 log += *log_num;
337 }
338 heads[headcount].id = d;
339 heads[headcount].len = iov_length(vq->iov + seg, in);
340 datalen -= heads[headcount].len;
341 ++headcount;
342 seg += in;
343 }
344 heads[headcount - 1].len += datalen;
345 *iovcount = seg;
346 if (unlikely(log))
347 *log_num = nlogs;
348 return headcount;
349err:
350 vhost_discard_vq_desc(vq, headcount);
351 return r;
352}
353
354/* Expects to be always run from workqueue - which acts as
355 * read-size critical section for our kind of RCU. */
356static void handle_rx(struct vhost_net *net)
357{
358 struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX];
359 unsigned uninitialized_var(in), log;
360 struct vhost_log *vq_log;
361 struct msghdr msg = {
362 .msg_name = NULL,
363 .msg_namelen = 0,
364 .msg_control = NULL, /* FIXME: get and handle RX aux data. */
365 .msg_controllen = 0,
366 .msg_iov = vq->iov,
367 .msg_flags = MSG_DONTWAIT,
368 };
369 struct virtio_net_hdr_mrg_rxbuf hdr = {
370 .hdr.flags = 0,
371 .hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE
372 };
373 size_t total_len = 0;
374 int err, headcount, mergeable;
375 size_t vhost_hlen, sock_hlen;
376 size_t vhost_len, sock_len;
377 /* TODO: check that we are running from vhost_worker? */
378 struct socket *sock = rcu_dereference_check(vq->private_data, 1);
379
380 if (!sock)
381 return;
382
383 mutex_lock(&vq->mutex);
384 vhost_disable_notify(&net->dev, vq);
385 vhost_hlen = vq->vhost_hlen;
386 sock_hlen = vq->sock_hlen;
387
388 vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ?
389 vq->log : NULL;
390 mergeable = vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF);
391
392 while ((sock_len = peek_head_len(sock->sk))) {
393 sock_len += sock_hlen;
394 vhost_len = sock_len + vhost_hlen;
395 headcount = get_rx_bufs(vq, vq->heads, vhost_len,
396 &in, vq_log, &log,
397 likely(mergeable) ? UIO_MAXIOV : 1);
398 /* On error, stop handling until the next kick. */
399 if (unlikely(headcount < 0))
400 break;
401 /* OK, now we need to know about added descriptors. */
402 if (!headcount) {
403 if (unlikely(vhost_enable_notify(&net->dev, vq))) {
404 /* They have slipped one in as we were
405 * doing that: check again. */
406 vhost_disable_notify(&net->dev, vq);
407 continue;
408 }
409 /* Nothing new? Wait for eventfd to tell us
410 * they refilled. */
411 break;
412 }
413 /* We don't need to be notified again. */
414 if (unlikely((vhost_hlen)))
415 /* Skip header. TODO: support TSO. */
416 move_iovec_hdr(vq->iov, vq->hdr, vhost_hlen, in);
417 else
418 /* Copy the header for use in VIRTIO_NET_F_MRG_RXBUF:
419 * needed because recvmsg can modify msg_iov. */
420 copy_iovec_hdr(vq->iov, vq->hdr, sock_hlen, in);
421 msg.msg_iovlen = in;
422 err = sock->ops->recvmsg(NULL, sock, &msg,
423 sock_len, MSG_DONTWAIT | MSG_TRUNC);
424 /* Userspace might have consumed the packet meanwhile:
425 * it's not supposed to do this usually, but might be hard
426 * to prevent. Discard data we got (if any) and keep going. */
427 if (unlikely(err != sock_len)) {
428 pr_debug("Discarded rx packet: "
429 " len %d, expected %zd\n", err, sock_len);
430 vhost_discard_vq_desc(vq, headcount);
431 continue;
432 }
433 if (unlikely(vhost_hlen) &&
434 memcpy_toiovecend(vq->hdr, (unsigned char *)&hdr, 0,
435 vhost_hlen)) {
436 vq_err(vq, "Unable to write vnet_hdr at addr %p\n",
437 vq->iov->iov_base);
438 break;
439 }
440 /* TODO: Should check and handle checksum. */
441 if (likely(mergeable) &&
442 memcpy_toiovecend(vq->hdr, (unsigned char *)&headcount,
443 offsetof(typeof(hdr), num_buffers),
444 sizeof hdr.num_buffers)) {
445 vq_err(vq, "Failed num_buffers write");
446 vhost_discard_vq_desc(vq, headcount);
447 break;
448 }
449 vhost_add_used_and_signal_n(&net->dev, vq, vq->heads,
450 headcount);
451 if (unlikely(vq_log))
452 vhost_log_write(vq, vq_log, log, vhost_len);
453 total_len += vhost_len;
454 if (unlikely(total_len >= VHOST_NET_WEIGHT)) {
455 vhost_poll_queue(&vq->poll);
456 break;
457 }
458 }
459
460 mutex_unlock(&vq->mutex);
461}
462
463static void handle_tx_kick(struct vhost_work *work)
464{
465 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
466 poll.work);
467 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
468
469 handle_tx(net);
470}
471
472static void handle_rx_kick(struct vhost_work *work)
473{
474 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
475 poll.work);
476 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
477
478 handle_rx(net);
479}
480
481static void handle_tx_net(struct vhost_work *work)
482{
483 struct vhost_net *net = container_of(work, struct vhost_net,
484 poll[VHOST_NET_VQ_TX].work);
485 handle_tx(net);
486}
487
488static void handle_rx_net(struct vhost_work *work)
489{
490 struct vhost_net *net = container_of(work, struct vhost_net,
491 poll[VHOST_NET_VQ_RX].work);
492 handle_rx(net);
493}
494
495static int vhost_net_open(struct inode *inode, struct file *f)
496{
497 struct vhost_net *n = kmalloc(sizeof *n, GFP_KERNEL);
498 struct vhost_dev *dev;
499 int r;
500
501 if (!n)
502 return -ENOMEM;
503
504 dev = &n->dev;
505 n->vqs[VHOST_NET_VQ_TX].handle_kick = handle_tx_kick;
506 n->vqs[VHOST_NET_VQ_RX].handle_kick = handle_rx_kick;
507 r = vhost_dev_init(dev, n->vqs, VHOST_NET_VQ_MAX);
508 if (r < 0) {
509 kfree(n);
510 return r;
511 }
512
513 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT, dev);
514 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN, dev);
515 n->tx_poll_state = VHOST_NET_POLL_DISABLED;
516
517 f->private_data = n;
518
519 return 0;
520}
521
522static void vhost_net_disable_vq(struct vhost_net *n,
523 struct vhost_virtqueue *vq)
524{
525 if (!vq->private_data)
526 return;
527 if (vq == n->vqs + VHOST_NET_VQ_TX) {
528 tx_poll_stop(n);
529 n->tx_poll_state = VHOST_NET_POLL_DISABLED;
530 } else
531 vhost_poll_stop(n->poll + VHOST_NET_VQ_RX);
532}
533
534static void vhost_net_enable_vq(struct vhost_net *n,
535 struct vhost_virtqueue *vq)
536{
537 struct socket *sock;
538
539 sock = rcu_dereference_protected(vq->private_data,
540 lockdep_is_held(&vq->mutex));
541 if (!sock)
542 return;
543 if (vq == n->vqs + VHOST_NET_VQ_TX) {
544 n->tx_poll_state = VHOST_NET_POLL_STOPPED;
545 tx_poll_start(n, sock);
546 } else
547 vhost_poll_start(n->poll + VHOST_NET_VQ_RX, sock->file);
548}
549
550static struct socket *vhost_net_stop_vq(struct vhost_net *n,
551 struct vhost_virtqueue *vq)
552{
553 struct socket *sock;
554
555 mutex_lock(&vq->mutex);
556 sock = rcu_dereference_protected(vq->private_data,
557 lockdep_is_held(&vq->mutex));
558 vhost_net_disable_vq(n, vq);
559 rcu_assign_pointer(vq->private_data, NULL);
560 mutex_unlock(&vq->mutex);
561 return sock;
562}
563
564static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock,
565 struct socket **rx_sock)
566{
567 *tx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_TX);
568 *rx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_RX);
569}
570
571static void vhost_net_flush_vq(struct vhost_net *n, int index)
572{
573 vhost_poll_flush(n->poll + index);
574 vhost_poll_flush(&n->dev.vqs[index].poll);
575}
576
577static void vhost_net_flush(struct vhost_net *n)
578{
579 vhost_net_flush_vq(n, VHOST_NET_VQ_TX);
580 vhost_net_flush_vq(n, VHOST_NET_VQ_RX);
581}
582
583static int vhost_net_release(struct inode *inode, struct file *f)
584{
585 struct vhost_net *n = f->private_data;
586 struct socket *tx_sock;
587 struct socket *rx_sock;
588
589 vhost_net_stop(n, &tx_sock, &rx_sock);
590 vhost_net_flush(n);
591 vhost_dev_cleanup(&n->dev);
592 if (tx_sock)
593 fput(tx_sock->file);
594 if (rx_sock)
595 fput(rx_sock->file);
596 /* We do an extra flush before freeing memory,
597 * since jobs can re-queue themselves. */
598 vhost_net_flush(n);
599 kfree(n);
600 return 0;
601}
602
603static struct socket *get_raw_socket(int fd)
604{
605 struct {
606 struct sockaddr_ll sa;
607 char buf[MAX_ADDR_LEN];
608 } uaddr;
609 int uaddr_len = sizeof uaddr, r;
610 struct socket *sock = sockfd_lookup(fd, &r);
611
612 if (!sock)
613 return ERR_PTR(-ENOTSOCK);
614
615 /* Parameter checking */
616 if (sock->sk->sk_type != SOCK_RAW) {
617 r = -ESOCKTNOSUPPORT;
618 goto err;
619 }
620
621 r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa,
622 &uaddr_len, 0);
623 if (r)
624 goto err;
625
626 if (uaddr.sa.sll_family != AF_PACKET) {
627 r = -EPFNOSUPPORT;
628 goto err;
629 }
630 return sock;
631err:
632 fput(sock->file);
633 return ERR_PTR(r);
634}
635
636static struct socket *get_tap_socket(int fd)
637{
638 struct file *file = fget(fd);
639 struct socket *sock;
640
641 if (!file)
642 return ERR_PTR(-EBADF);
643 sock = tun_get_socket(file);
644 if (!IS_ERR(sock))
645 return sock;
646 sock = macvtap_get_socket(file);
647 if (IS_ERR(sock))
648 fput(file);
649 return sock;
650}
651
652static struct socket *get_socket(int fd)
653{
654 struct socket *sock;
655
656 /* special case to disable backend */
657 if (fd == -1)
658 return NULL;
659 sock = get_raw_socket(fd);
660 if (!IS_ERR(sock))
661 return sock;
662 sock = get_tap_socket(fd);
663 if (!IS_ERR(sock))
664 return sock;
665 return ERR_PTR(-ENOTSOCK);
666}
667
668static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
669{
670 struct socket *sock, *oldsock;
671 struct vhost_virtqueue *vq;
672 struct vhost_ubuf_ref *ubufs, *oldubufs = NULL;
673 int r;
674
675 mutex_lock(&n->dev.mutex);
676 r = vhost_dev_check_owner(&n->dev);
677 if (r)
678 goto err;
679
680 if (index >= VHOST_NET_VQ_MAX) {
681 r = -ENOBUFS;
682 goto err;
683 }
684 vq = n->vqs + index;
685 mutex_lock(&vq->mutex);
686
687 /* Verify that ring has been setup correctly. */
688 if (!vhost_vq_access_ok(vq)) {
689 r = -EFAULT;
690 goto err_vq;
691 }
692 sock = get_socket(fd);
693 if (IS_ERR(sock)) {
694 r = PTR_ERR(sock);
695 goto err_vq;
696 }
697
698 /* start polling new socket */
699 oldsock = rcu_dereference_protected(vq->private_data,
700 lockdep_is_held(&vq->mutex));
701 if (sock != oldsock) {
702 ubufs = vhost_ubuf_alloc(vq, sock && vhost_sock_zcopy(sock));
703 if (IS_ERR(ubufs)) {
704 r = PTR_ERR(ubufs);
705 goto err_ubufs;
706 }
707 oldubufs = vq->ubufs;
708 vq->ubufs = ubufs;
709 vhost_net_disable_vq(n, vq);
710 rcu_assign_pointer(vq->private_data, sock);
711 vhost_net_enable_vq(n, vq);
712
713 r = vhost_init_used(vq);
714 if (r)
715 goto err_vq;
716 }
717
718 mutex_unlock(&vq->mutex);
719
720 if (oldubufs) {
721 vhost_ubuf_put_and_wait(oldubufs);
722 mutex_lock(&vq->mutex);
723 vhost_zerocopy_signal_used(vq);
724 mutex_unlock(&vq->mutex);
725 }
726
727 if (oldsock) {
728 vhost_net_flush_vq(n, index);
729 fput(oldsock->file);
730 }
731
732 mutex_unlock(&n->dev.mutex);
733 return 0;
734
735err_ubufs:
736 fput(sock->file);
737err_vq:
738 mutex_unlock(&vq->mutex);
739err:
740 mutex_unlock(&n->dev.mutex);
741 return r;
742}
743
744static long vhost_net_reset_owner(struct vhost_net *n)
745{
746 struct socket *tx_sock = NULL;
747 struct socket *rx_sock = NULL;
748 long err;
749
750 mutex_lock(&n->dev.mutex);
751 err = vhost_dev_check_owner(&n->dev);
752 if (err)
753 goto done;
754 vhost_net_stop(n, &tx_sock, &rx_sock);
755 vhost_net_flush(n);
756 err = vhost_dev_reset_owner(&n->dev);
757done:
758 mutex_unlock(&n->dev.mutex);
759 if (tx_sock)
760 fput(tx_sock->file);
761 if (rx_sock)
762 fput(rx_sock->file);
763 return err;
764}
765
766static int vhost_net_set_features(struct vhost_net *n, u64 features)
767{
768 size_t vhost_hlen, sock_hlen, hdr_len;
769 int i;
770
771 hdr_len = (features & (1 << VIRTIO_NET_F_MRG_RXBUF)) ?
772 sizeof(struct virtio_net_hdr_mrg_rxbuf) :
773 sizeof(struct virtio_net_hdr);
774 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) {
775 /* vhost provides vnet_hdr */
776 vhost_hlen = hdr_len;
777 sock_hlen = 0;
778 } else {
779 /* socket provides vnet_hdr */
780 vhost_hlen = 0;
781 sock_hlen = hdr_len;
782 }
783 mutex_lock(&n->dev.mutex);
784 if ((features & (1 << VHOST_F_LOG_ALL)) &&
785 !vhost_log_access_ok(&n->dev)) {
786 mutex_unlock(&n->dev.mutex);
787 return -EFAULT;
788 }
789 n->dev.acked_features = features;
790 smp_wmb();
791 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
792 mutex_lock(&n->vqs[i].mutex);
793 n->vqs[i].vhost_hlen = vhost_hlen;
794 n->vqs[i].sock_hlen = sock_hlen;
795 mutex_unlock(&n->vqs[i].mutex);
796 }
797 vhost_net_flush(n);
798 mutex_unlock(&n->dev.mutex);
799 return 0;
800}
801
802static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
803 unsigned long arg)
804{
805 struct vhost_net *n = f->private_data;
806 void __user *argp = (void __user *)arg;
807 u64 __user *featurep = argp;
808 struct vhost_vring_file backend;
809 u64 features;
810 int r;
811
812 switch (ioctl) {
813 case VHOST_NET_SET_BACKEND:
814 if (copy_from_user(&backend, argp, sizeof backend))
815 return -EFAULT;
816 return vhost_net_set_backend(n, backend.index, backend.fd);
817 case VHOST_GET_FEATURES:
818 features = VHOST_FEATURES;
819 if (copy_to_user(featurep, &features, sizeof features))
820 return -EFAULT;
821 return 0;
822 case VHOST_SET_FEATURES:
823 if (copy_from_user(&features, featurep, sizeof features))
824 return -EFAULT;
825 if (features & ~VHOST_FEATURES)
826 return -EOPNOTSUPP;
827 return vhost_net_set_features(n, features);
828 case VHOST_RESET_OWNER:
829 return vhost_net_reset_owner(n);
830 default:
831 mutex_lock(&n->dev.mutex);
832 r = vhost_dev_ioctl(&n->dev, ioctl, arg);
833 vhost_net_flush(n);
834 mutex_unlock(&n->dev.mutex);
835 return r;
836 }
837}
838
839#ifdef CONFIG_COMPAT
840static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl,
841 unsigned long arg)
842{
843 return vhost_net_ioctl(f, ioctl, (unsigned long)compat_ptr(arg));
844}
845#endif
846
847static const struct file_operations vhost_net_fops = {
848 .owner = THIS_MODULE,
849 .release = vhost_net_release,
850 .unlocked_ioctl = vhost_net_ioctl,
851#ifdef CONFIG_COMPAT
852 .compat_ioctl = vhost_net_compat_ioctl,
853#endif
854 .open = vhost_net_open,
855 .llseek = noop_llseek,
856};
857
858static struct miscdevice vhost_net_misc = {
859 MISC_DYNAMIC_MINOR,
860 "vhost-net",
861 &vhost_net_fops,
862};
863
864static int vhost_net_init(void)
865{
866 if (experimental_zcopytx)
867 vhost_enable_zcopy(VHOST_NET_VQ_TX);
868 return misc_register(&vhost_net_misc);
869}
870module_init(vhost_net_init);
871
872static void vhost_net_exit(void)
873{
874 misc_deregister(&vhost_net_misc);
875}
876module_exit(vhost_net_exit);
877
878MODULE_VERSION("0.0.1");
879MODULE_LICENSE("GPL v2");
880MODULE_AUTHOR("Michael S. Tsirkin");
881MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
1// SPDX-License-Identifier: GPL-2.0-only
2/* Copyright (C) 2009 Red Hat, Inc.
3 * Author: Michael S. Tsirkin <mst@redhat.com>
4 *
5 * virtio-net server in host kernel.
6 */
7
8#include <linux/compat.h>
9#include <linux/eventfd.h>
10#include <linux/vhost.h>
11#include <linux/virtio_net.h>
12#include <linux/miscdevice.h>
13#include <linux/module.h>
14#include <linux/moduleparam.h>
15#include <linux/mutex.h>
16#include <linux/workqueue.h>
17#include <linux/file.h>
18#include <linux/slab.h>
19#include <linux/sched/clock.h>
20#include <linux/sched/signal.h>
21#include <linux/vmalloc.h>
22
23#include <linux/net.h>
24#include <linux/if_packet.h>
25#include <linux/if_arp.h>
26#include <linux/if_tun.h>
27#include <linux/if_macvlan.h>
28#include <linux/if_tap.h>
29#include <linux/if_vlan.h>
30#include <linux/skb_array.h>
31#include <linux/skbuff.h>
32
33#include <net/sock.h>
34#include <net/xdp.h>
35
36#include "vhost.h"
37
38static int experimental_zcopytx = 0;
39module_param(experimental_zcopytx, int, 0444);
40MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;"
41 " 1 -Enable; 0 - Disable");
42
43/* Max number of bytes transferred before requeueing the job.
44 * Using this limit prevents one virtqueue from starving others. */
45#define VHOST_NET_WEIGHT 0x80000
46
47/* Max number of packets transferred before requeueing the job.
48 * Using this limit prevents one virtqueue from starving others with small
49 * pkts.
50 */
51#define VHOST_NET_PKT_WEIGHT 256
52
53/* MAX number of TX used buffers for outstanding zerocopy */
54#define VHOST_MAX_PEND 128
55#define VHOST_GOODCOPY_LEN 256
56
57/*
58 * For transmit, used buffer len is unused; we override it to track buffer
59 * status internally; used for zerocopy tx only.
60 */
61/* Lower device DMA failed */
62#define VHOST_DMA_FAILED_LEN ((__force __virtio32)3)
63/* Lower device DMA done */
64#define VHOST_DMA_DONE_LEN ((__force __virtio32)2)
65/* Lower device DMA in progress */
66#define VHOST_DMA_IN_PROGRESS ((__force __virtio32)1)
67/* Buffer unused */
68#define VHOST_DMA_CLEAR_LEN ((__force __virtio32)0)
69
70#define VHOST_DMA_IS_DONE(len) ((__force u32)(len) >= (__force u32)VHOST_DMA_DONE_LEN)
71
72enum {
73 VHOST_NET_FEATURES = VHOST_FEATURES |
74 (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |
75 (1ULL << VIRTIO_NET_F_MRG_RXBUF) |
76 (1ULL << VIRTIO_F_IOMMU_PLATFORM)
77};
78
79enum {
80 VHOST_NET_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2)
81};
82
83enum {
84 VHOST_NET_VQ_RX = 0,
85 VHOST_NET_VQ_TX = 1,
86 VHOST_NET_VQ_MAX = 2,
87};
88
89struct vhost_net_ubuf_ref {
90 /* refcount follows semantics similar to kref:
91 * 0: object is released
92 * 1: no outstanding ubufs
93 * >1: outstanding ubufs
94 */
95 atomic_t refcount;
96 wait_queue_head_t wait;
97 struct vhost_virtqueue *vq;
98};
99
100#define VHOST_NET_BATCH 64
101struct vhost_net_buf {
102 void **queue;
103 int tail;
104 int head;
105};
106
107struct vhost_net_virtqueue {
108 struct vhost_virtqueue vq;
109 size_t vhost_hlen;
110 size_t sock_hlen;
111 /* vhost zerocopy support fields below: */
112 /* last used idx for outstanding DMA zerocopy buffers */
113 int upend_idx;
114 /* For TX, first used idx for DMA done zerocopy buffers
115 * For RX, number of batched heads
116 */
117 int done_idx;
118 /* Number of XDP frames batched */
119 int batched_xdp;
120 /* an array of userspace buffers info */
121 struct ubuf_info *ubuf_info;
122 /* Reference counting for outstanding ubufs.
123 * Protected by vq mutex. Writers must also take device mutex. */
124 struct vhost_net_ubuf_ref *ubufs;
125 struct ptr_ring *rx_ring;
126 struct vhost_net_buf rxq;
127 /* Batched XDP buffs */
128 struct xdp_buff *xdp;
129};
130
131struct vhost_net {
132 struct vhost_dev dev;
133 struct vhost_net_virtqueue vqs[VHOST_NET_VQ_MAX];
134 struct vhost_poll poll[VHOST_NET_VQ_MAX];
135 /* Number of TX recently submitted.
136 * Protected by tx vq lock. */
137 unsigned tx_packets;
138 /* Number of times zerocopy TX recently failed.
139 * Protected by tx vq lock. */
140 unsigned tx_zcopy_err;
141 /* Flush in progress. Protected by tx vq lock. */
142 bool tx_flush;
143 /* Private page frag */
144 struct page_frag page_frag;
145 /* Refcount bias of page frag */
146 int refcnt_bias;
147};
148
149static unsigned vhost_net_zcopy_mask __read_mostly;
150
151static void *vhost_net_buf_get_ptr(struct vhost_net_buf *rxq)
152{
153 if (rxq->tail != rxq->head)
154 return rxq->queue[rxq->head];
155 else
156 return NULL;
157}
158
159static int vhost_net_buf_get_size(struct vhost_net_buf *rxq)
160{
161 return rxq->tail - rxq->head;
162}
163
164static int vhost_net_buf_is_empty(struct vhost_net_buf *rxq)
165{
166 return rxq->tail == rxq->head;
167}
168
169static void *vhost_net_buf_consume(struct vhost_net_buf *rxq)
170{
171 void *ret = vhost_net_buf_get_ptr(rxq);
172 ++rxq->head;
173 return ret;
174}
175
176static int vhost_net_buf_produce(struct vhost_net_virtqueue *nvq)
177{
178 struct vhost_net_buf *rxq = &nvq->rxq;
179
180 rxq->head = 0;
181 rxq->tail = ptr_ring_consume_batched(nvq->rx_ring, rxq->queue,
182 VHOST_NET_BATCH);
183 return rxq->tail;
184}
185
186static void vhost_net_buf_unproduce(struct vhost_net_virtqueue *nvq)
187{
188 struct vhost_net_buf *rxq = &nvq->rxq;
189
190 if (nvq->rx_ring && !vhost_net_buf_is_empty(rxq)) {
191 ptr_ring_unconsume(nvq->rx_ring, rxq->queue + rxq->head,
192 vhost_net_buf_get_size(rxq),
193 tun_ptr_free);
194 rxq->head = rxq->tail = 0;
195 }
196}
197
198static int vhost_net_buf_peek_len(void *ptr)
199{
200 if (tun_is_xdp_frame(ptr)) {
201 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
202
203 return xdpf->len;
204 }
205
206 return __skb_array_len_with_tag(ptr);
207}
208
209static int vhost_net_buf_peek(struct vhost_net_virtqueue *nvq)
210{
211 struct vhost_net_buf *rxq = &nvq->rxq;
212
213 if (!vhost_net_buf_is_empty(rxq))
214 goto out;
215
216 if (!vhost_net_buf_produce(nvq))
217 return 0;
218
219out:
220 return vhost_net_buf_peek_len(vhost_net_buf_get_ptr(rxq));
221}
222
223static void vhost_net_buf_init(struct vhost_net_buf *rxq)
224{
225 rxq->head = rxq->tail = 0;
226}
227
228static void vhost_net_enable_zcopy(int vq)
229{
230 vhost_net_zcopy_mask |= 0x1 << vq;
231}
232
233static struct vhost_net_ubuf_ref *
234vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy)
235{
236 struct vhost_net_ubuf_ref *ubufs;
237 /* No zero copy backend? Nothing to count. */
238 if (!zcopy)
239 return NULL;
240 ubufs = kmalloc(sizeof(*ubufs), GFP_KERNEL);
241 if (!ubufs)
242 return ERR_PTR(-ENOMEM);
243 atomic_set(&ubufs->refcount, 1);
244 init_waitqueue_head(&ubufs->wait);
245 ubufs->vq = vq;
246 return ubufs;
247}
248
249static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs)
250{
251 int r = atomic_sub_return(1, &ubufs->refcount);
252 if (unlikely(!r))
253 wake_up(&ubufs->wait);
254 return r;
255}
256
257static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs)
258{
259 vhost_net_ubuf_put(ubufs);
260 wait_event(ubufs->wait, !atomic_read(&ubufs->refcount));
261}
262
263static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs)
264{
265 vhost_net_ubuf_put_and_wait(ubufs);
266 kfree(ubufs);
267}
268
269static void vhost_net_clear_ubuf_info(struct vhost_net *n)
270{
271 int i;
272
273 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
274 kfree(n->vqs[i].ubuf_info);
275 n->vqs[i].ubuf_info = NULL;
276 }
277}
278
279static int vhost_net_set_ubuf_info(struct vhost_net *n)
280{
281 bool zcopy;
282 int i;
283
284 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
285 zcopy = vhost_net_zcopy_mask & (0x1 << i);
286 if (!zcopy)
287 continue;
288 n->vqs[i].ubuf_info =
289 kmalloc_array(UIO_MAXIOV,
290 sizeof(*n->vqs[i].ubuf_info),
291 GFP_KERNEL);
292 if (!n->vqs[i].ubuf_info)
293 goto err;
294 }
295 return 0;
296
297err:
298 vhost_net_clear_ubuf_info(n);
299 return -ENOMEM;
300}
301
302static void vhost_net_vq_reset(struct vhost_net *n)
303{
304 int i;
305
306 vhost_net_clear_ubuf_info(n);
307
308 for (i = 0; i < VHOST_NET_VQ_MAX; i++) {
309 n->vqs[i].done_idx = 0;
310 n->vqs[i].upend_idx = 0;
311 n->vqs[i].ubufs = NULL;
312 n->vqs[i].vhost_hlen = 0;
313 n->vqs[i].sock_hlen = 0;
314 vhost_net_buf_init(&n->vqs[i].rxq);
315 }
316
317}
318
319static void vhost_net_tx_packet(struct vhost_net *net)
320{
321 ++net->tx_packets;
322 if (net->tx_packets < 1024)
323 return;
324 net->tx_packets = 0;
325 net->tx_zcopy_err = 0;
326}
327
328static void vhost_net_tx_err(struct vhost_net *net)
329{
330 ++net->tx_zcopy_err;
331}
332
333static bool vhost_net_tx_select_zcopy(struct vhost_net *net)
334{
335 /* TX flush waits for outstanding DMAs to be done.
336 * Don't start new DMAs.
337 */
338 return !net->tx_flush &&
339 net->tx_packets / 64 >= net->tx_zcopy_err;
340}
341
342static bool vhost_sock_zcopy(struct socket *sock)
343{
344 return unlikely(experimental_zcopytx) &&
345 sock_flag(sock->sk, SOCK_ZEROCOPY);
346}
347
348static bool vhost_sock_xdp(struct socket *sock)
349{
350 return sock_flag(sock->sk, SOCK_XDP);
351}
352
353/* In case of DMA done not in order in lower device driver for some reason.
354 * upend_idx is used to track end of used idx, done_idx is used to track head
355 * of used idx. Once lower device DMA done contiguously, we will signal KVM
356 * guest used idx.
357 */
358static void vhost_zerocopy_signal_used(struct vhost_net *net,
359 struct vhost_virtqueue *vq)
360{
361 struct vhost_net_virtqueue *nvq =
362 container_of(vq, struct vhost_net_virtqueue, vq);
363 int i, add;
364 int j = 0;
365
366 for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) {
367 if (vq->heads[i].len == VHOST_DMA_FAILED_LEN)
368 vhost_net_tx_err(net);
369 if (VHOST_DMA_IS_DONE(vq->heads[i].len)) {
370 vq->heads[i].len = VHOST_DMA_CLEAR_LEN;
371 ++j;
372 } else
373 break;
374 }
375 while (j) {
376 add = min(UIO_MAXIOV - nvq->done_idx, j);
377 vhost_add_used_and_signal_n(vq->dev, vq,
378 &vq->heads[nvq->done_idx], add);
379 nvq->done_idx = (nvq->done_idx + add) % UIO_MAXIOV;
380 j -= add;
381 }
382}
383
384static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success)
385{
386 struct vhost_net_ubuf_ref *ubufs = ubuf->ctx;
387 struct vhost_virtqueue *vq = ubufs->vq;
388 int cnt;
389
390 rcu_read_lock_bh();
391
392 /* set len to mark this desc buffers done DMA */
393 vq->heads[ubuf->desc].len = success ?
394 VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN;
395 cnt = vhost_net_ubuf_put(ubufs);
396
397 /*
398 * Trigger polling thread if guest stopped submitting new buffers:
399 * in this case, the refcount after decrement will eventually reach 1.
400 * We also trigger polling periodically after each 16 packets
401 * (the value 16 here is more or less arbitrary, it's tuned to trigger
402 * less than 10% of times).
403 */
404 if (cnt <= 1 || !(cnt % 16))
405 vhost_poll_queue(&vq->poll);
406
407 rcu_read_unlock_bh();
408}
409
410static inline unsigned long busy_clock(void)
411{
412 return local_clock() >> 10;
413}
414
415static bool vhost_can_busy_poll(unsigned long endtime)
416{
417 return likely(!need_resched() && !time_after(busy_clock(), endtime) &&
418 !signal_pending(current));
419}
420
421static void vhost_net_disable_vq(struct vhost_net *n,
422 struct vhost_virtqueue *vq)
423{
424 struct vhost_net_virtqueue *nvq =
425 container_of(vq, struct vhost_net_virtqueue, vq);
426 struct vhost_poll *poll = n->poll + (nvq - n->vqs);
427 if (!vq->private_data)
428 return;
429 vhost_poll_stop(poll);
430}
431
432static int vhost_net_enable_vq(struct vhost_net *n,
433 struct vhost_virtqueue *vq)
434{
435 struct vhost_net_virtqueue *nvq =
436 container_of(vq, struct vhost_net_virtqueue, vq);
437 struct vhost_poll *poll = n->poll + (nvq - n->vqs);
438 struct socket *sock;
439
440 sock = vq->private_data;
441 if (!sock)
442 return 0;
443
444 return vhost_poll_start(poll, sock->file);
445}
446
447static void vhost_net_signal_used(struct vhost_net_virtqueue *nvq)
448{
449 struct vhost_virtqueue *vq = &nvq->vq;
450 struct vhost_dev *dev = vq->dev;
451
452 if (!nvq->done_idx)
453 return;
454
455 vhost_add_used_and_signal_n(dev, vq, vq->heads, nvq->done_idx);
456 nvq->done_idx = 0;
457}
458
459static void vhost_tx_batch(struct vhost_net *net,
460 struct vhost_net_virtqueue *nvq,
461 struct socket *sock,
462 struct msghdr *msghdr)
463{
464 struct tun_msg_ctl ctl = {
465 .type = TUN_MSG_PTR,
466 .num = nvq->batched_xdp,
467 .ptr = nvq->xdp,
468 };
469 int err;
470
471 if (nvq->batched_xdp == 0)
472 goto signal_used;
473
474 msghdr->msg_control = &ctl;
475 err = sock->ops->sendmsg(sock, msghdr, 0);
476 if (unlikely(err < 0)) {
477 vq_err(&nvq->vq, "Fail to batch sending packets\n");
478 return;
479 }
480
481signal_used:
482 vhost_net_signal_used(nvq);
483 nvq->batched_xdp = 0;
484}
485
486static int sock_has_rx_data(struct socket *sock)
487{
488 if (unlikely(!sock))
489 return 0;
490
491 if (sock->ops->peek_len)
492 return sock->ops->peek_len(sock);
493
494 return skb_queue_empty(&sock->sk->sk_receive_queue);
495}
496
497static void vhost_net_busy_poll_try_queue(struct vhost_net *net,
498 struct vhost_virtqueue *vq)
499{
500 if (!vhost_vq_avail_empty(&net->dev, vq)) {
501 vhost_poll_queue(&vq->poll);
502 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) {
503 vhost_disable_notify(&net->dev, vq);
504 vhost_poll_queue(&vq->poll);
505 }
506}
507
508static void vhost_net_busy_poll(struct vhost_net *net,
509 struct vhost_virtqueue *rvq,
510 struct vhost_virtqueue *tvq,
511 bool *busyloop_intr,
512 bool poll_rx)
513{
514 unsigned long busyloop_timeout;
515 unsigned long endtime;
516 struct socket *sock;
517 struct vhost_virtqueue *vq = poll_rx ? tvq : rvq;
518
519 /* Try to hold the vq mutex of the paired virtqueue. We can't
520 * use mutex_lock() here since we could not guarantee a
521 * consistenet lock ordering.
522 */
523 if (!mutex_trylock(&vq->mutex))
524 return;
525
526 vhost_disable_notify(&net->dev, vq);
527 sock = rvq->private_data;
528
529 busyloop_timeout = poll_rx ? rvq->busyloop_timeout:
530 tvq->busyloop_timeout;
531
532 preempt_disable();
533 endtime = busy_clock() + busyloop_timeout;
534
535 while (vhost_can_busy_poll(endtime)) {
536 if (vhost_has_work(&net->dev)) {
537 *busyloop_intr = true;
538 break;
539 }
540
541 if ((sock_has_rx_data(sock) &&
542 !vhost_vq_avail_empty(&net->dev, rvq)) ||
543 !vhost_vq_avail_empty(&net->dev, tvq))
544 break;
545
546 cpu_relax();
547 }
548
549 preempt_enable();
550
551 if (poll_rx || sock_has_rx_data(sock))
552 vhost_net_busy_poll_try_queue(net, vq);
553 else if (!poll_rx) /* On tx here, sock has no rx data. */
554 vhost_enable_notify(&net->dev, rvq);
555
556 mutex_unlock(&vq->mutex);
557}
558
559static int vhost_net_tx_get_vq_desc(struct vhost_net *net,
560 struct vhost_net_virtqueue *tnvq,
561 unsigned int *out_num, unsigned int *in_num,
562 struct msghdr *msghdr, bool *busyloop_intr)
563{
564 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX];
565 struct vhost_virtqueue *rvq = &rnvq->vq;
566 struct vhost_virtqueue *tvq = &tnvq->vq;
567
568 int r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov),
569 out_num, in_num, NULL, NULL);
570
571 if (r == tvq->num && tvq->busyloop_timeout) {
572 /* Flush batched packets first */
573 if (!vhost_sock_zcopy(tvq->private_data))
574 vhost_tx_batch(net, tnvq, tvq->private_data, msghdr);
575
576 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, false);
577
578 r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov),
579 out_num, in_num, NULL, NULL);
580 }
581
582 return r;
583}
584
585static bool vhost_exceeds_maxpend(struct vhost_net *net)
586{
587 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
588 struct vhost_virtqueue *vq = &nvq->vq;
589
590 return (nvq->upend_idx + UIO_MAXIOV - nvq->done_idx) % UIO_MAXIOV >
591 min_t(unsigned int, VHOST_MAX_PEND, vq->num >> 2);
592}
593
594static size_t init_iov_iter(struct vhost_virtqueue *vq, struct iov_iter *iter,
595 size_t hdr_size, int out)
596{
597 /* Skip header. TODO: support TSO. */
598 size_t len = iov_length(vq->iov, out);
599
600 iov_iter_init(iter, WRITE, vq->iov, out, len);
601 iov_iter_advance(iter, hdr_size);
602
603 return iov_iter_count(iter);
604}
605
606static int get_tx_bufs(struct vhost_net *net,
607 struct vhost_net_virtqueue *nvq,
608 struct msghdr *msg,
609 unsigned int *out, unsigned int *in,
610 size_t *len, bool *busyloop_intr)
611{
612 struct vhost_virtqueue *vq = &nvq->vq;
613 int ret;
614
615 ret = vhost_net_tx_get_vq_desc(net, nvq, out, in, msg, busyloop_intr);
616
617 if (ret < 0 || ret == vq->num)
618 return ret;
619
620 if (*in) {
621 vq_err(vq, "Unexpected descriptor format for TX: out %d, int %d\n",
622 *out, *in);
623 return -EFAULT;
624 }
625
626 /* Sanity check */
627 *len = init_iov_iter(vq, &msg->msg_iter, nvq->vhost_hlen, *out);
628 if (*len == 0) {
629 vq_err(vq, "Unexpected header len for TX: %zd expected %zd\n",
630 *len, nvq->vhost_hlen);
631 return -EFAULT;
632 }
633
634 return ret;
635}
636
637static bool tx_can_batch(struct vhost_virtqueue *vq, size_t total_len)
638{
639 return total_len < VHOST_NET_WEIGHT &&
640 !vhost_vq_avail_empty(vq->dev, vq);
641}
642
643#define SKB_FRAG_PAGE_ORDER get_order(32768)
644
645static bool vhost_net_page_frag_refill(struct vhost_net *net, unsigned int sz,
646 struct page_frag *pfrag, gfp_t gfp)
647{
648 if (pfrag->page) {
649 if (pfrag->offset + sz <= pfrag->size)
650 return true;
651 __page_frag_cache_drain(pfrag->page, net->refcnt_bias);
652 }
653
654 pfrag->offset = 0;
655 net->refcnt_bias = 0;
656 if (SKB_FRAG_PAGE_ORDER) {
657 /* Avoid direct reclaim but allow kswapd to wake */
658 pfrag->page = alloc_pages((gfp & ~__GFP_DIRECT_RECLAIM) |
659 __GFP_COMP | __GFP_NOWARN |
660 __GFP_NORETRY,
661 SKB_FRAG_PAGE_ORDER);
662 if (likely(pfrag->page)) {
663 pfrag->size = PAGE_SIZE << SKB_FRAG_PAGE_ORDER;
664 goto done;
665 }
666 }
667 pfrag->page = alloc_page(gfp);
668 if (likely(pfrag->page)) {
669 pfrag->size = PAGE_SIZE;
670 goto done;
671 }
672 return false;
673
674done:
675 net->refcnt_bias = USHRT_MAX;
676 page_ref_add(pfrag->page, USHRT_MAX - 1);
677 return true;
678}
679
680#define VHOST_NET_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
681
682static int vhost_net_build_xdp(struct vhost_net_virtqueue *nvq,
683 struct iov_iter *from)
684{
685 struct vhost_virtqueue *vq = &nvq->vq;
686 struct vhost_net *net = container_of(vq->dev, struct vhost_net,
687 dev);
688 struct socket *sock = vq->private_data;
689 struct page_frag *alloc_frag = &net->page_frag;
690 struct virtio_net_hdr *gso;
691 struct xdp_buff *xdp = &nvq->xdp[nvq->batched_xdp];
692 struct tun_xdp_hdr *hdr;
693 size_t len = iov_iter_count(from);
694 int headroom = vhost_sock_xdp(sock) ? XDP_PACKET_HEADROOM : 0;
695 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
696 int pad = SKB_DATA_ALIGN(VHOST_NET_RX_PAD + headroom + nvq->sock_hlen);
697 int sock_hlen = nvq->sock_hlen;
698 void *buf;
699 int copied;
700
701 if (unlikely(len < nvq->sock_hlen))
702 return -EFAULT;
703
704 if (SKB_DATA_ALIGN(len + pad) +
705 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
706 return -ENOSPC;
707
708 buflen += SKB_DATA_ALIGN(len + pad);
709 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
710 if (unlikely(!vhost_net_page_frag_refill(net, buflen,
711 alloc_frag, GFP_KERNEL)))
712 return -ENOMEM;
713
714 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
715 copied = copy_page_from_iter(alloc_frag->page,
716 alloc_frag->offset +
717 offsetof(struct tun_xdp_hdr, gso),
718 sock_hlen, from);
719 if (copied != sock_hlen)
720 return -EFAULT;
721
722 hdr = buf;
723 gso = &hdr->gso;
724
725 if ((gso->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
726 vhost16_to_cpu(vq, gso->csum_start) +
727 vhost16_to_cpu(vq, gso->csum_offset) + 2 >
728 vhost16_to_cpu(vq, gso->hdr_len)) {
729 gso->hdr_len = cpu_to_vhost16(vq,
730 vhost16_to_cpu(vq, gso->csum_start) +
731 vhost16_to_cpu(vq, gso->csum_offset) + 2);
732
733 if (vhost16_to_cpu(vq, gso->hdr_len) > len)
734 return -EINVAL;
735 }
736
737 len -= sock_hlen;
738 copied = copy_page_from_iter(alloc_frag->page,
739 alloc_frag->offset + pad,
740 len, from);
741 if (copied != len)
742 return -EFAULT;
743
744 xdp->data_hard_start = buf;
745 xdp->data = buf + pad;
746 xdp->data_end = xdp->data + len;
747 hdr->buflen = buflen;
748
749 --net->refcnt_bias;
750 alloc_frag->offset += buflen;
751
752 ++nvq->batched_xdp;
753
754 return 0;
755}
756
757static void handle_tx_copy(struct vhost_net *net, struct socket *sock)
758{
759 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
760 struct vhost_virtqueue *vq = &nvq->vq;
761 unsigned out, in;
762 int head;
763 struct msghdr msg = {
764 .msg_name = NULL,
765 .msg_namelen = 0,
766 .msg_control = NULL,
767 .msg_controllen = 0,
768 .msg_flags = MSG_DONTWAIT,
769 };
770 size_t len, total_len = 0;
771 int err;
772 int sent_pkts = 0;
773 bool sock_can_batch = (sock->sk->sk_sndbuf == INT_MAX);
774
775 do {
776 bool busyloop_intr = false;
777
778 if (nvq->done_idx == VHOST_NET_BATCH)
779 vhost_tx_batch(net, nvq, sock, &msg);
780
781 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len,
782 &busyloop_intr);
783 /* On error, stop handling until the next kick. */
784 if (unlikely(head < 0))
785 break;
786 /* Nothing new? Wait for eventfd to tell us they refilled. */
787 if (head == vq->num) {
788 if (unlikely(busyloop_intr)) {
789 vhost_poll_queue(&vq->poll);
790 } else if (unlikely(vhost_enable_notify(&net->dev,
791 vq))) {
792 vhost_disable_notify(&net->dev, vq);
793 continue;
794 }
795 break;
796 }
797
798 total_len += len;
799
800 /* For simplicity, TX batching is only enabled if
801 * sndbuf is unlimited.
802 */
803 if (sock_can_batch) {
804 err = vhost_net_build_xdp(nvq, &msg.msg_iter);
805 if (!err) {
806 goto done;
807 } else if (unlikely(err != -ENOSPC)) {
808 vhost_tx_batch(net, nvq, sock, &msg);
809 vhost_discard_vq_desc(vq, 1);
810 vhost_net_enable_vq(net, vq);
811 break;
812 }
813
814 /* We can't build XDP buff, go for single
815 * packet path but let's flush batched
816 * packets.
817 */
818 vhost_tx_batch(net, nvq, sock, &msg);
819 msg.msg_control = NULL;
820 } else {
821 if (tx_can_batch(vq, total_len))
822 msg.msg_flags |= MSG_MORE;
823 else
824 msg.msg_flags &= ~MSG_MORE;
825 }
826
827 /* TODO: Check specific error and bomb out unless ENOBUFS? */
828 err = sock->ops->sendmsg(sock, &msg, len);
829 if (unlikely(err < 0)) {
830 vhost_discard_vq_desc(vq, 1);
831 vhost_net_enable_vq(net, vq);
832 break;
833 }
834 if (err != len)
835 pr_debug("Truncated TX packet: len %d != %zd\n",
836 err, len);
837done:
838 vq->heads[nvq->done_idx].id = cpu_to_vhost32(vq, head);
839 vq->heads[nvq->done_idx].len = 0;
840 ++nvq->done_idx;
841 } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len)));
842
843 vhost_tx_batch(net, nvq, sock, &msg);
844}
845
846static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock)
847{
848 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
849 struct vhost_virtqueue *vq = &nvq->vq;
850 unsigned out, in;
851 int head;
852 struct msghdr msg = {
853 .msg_name = NULL,
854 .msg_namelen = 0,
855 .msg_control = NULL,
856 .msg_controllen = 0,
857 .msg_flags = MSG_DONTWAIT,
858 };
859 struct tun_msg_ctl ctl;
860 size_t len, total_len = 0;
861 int err;
862 struct vhost_net_ubuf_ref *uninitialized_var(ubufs);
863 bool zcopy_used;
864 int sent_pkts = 0;
865
866 do {
867 bool busyloop_intr;
868
869 /* Release DMAs done buffers first */
870 vhost_zerocopy_signal_used(net, vq);
871
872 busyloop_intr = false;
873 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len,
874 &busyloop_intr);
875 /* On error, stop handling until the next kick. */
876 if (unlikely(head < 0))
877 break;
878 /* Nothing new? Wait for eventfd to tell us they refilled. */
879 if (head == vq->num) {
880 if (unlikely(busyloop_intr)) {
881 vhost_poll_queue(&vq->poll);
882 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) {
883 vhost_disable_notify(&net->dev, vq);
884 continue;
885 }
886 break;
887 }
888
889 zcopy_used = len >= VHOST_GOODCOPY_LEN
890 && !vhost_exceeds_maxpend(net)
891 && vhost_net_tx_select_zcopy(net);
892
893 /* use msg_control to pass vhost zerocopy ubuf info to skb */
894 if (zcopy_used) {
895 struct ubuf_info *ubuf;
896 ubuf = nvq->ubuf_info + nvq->upend_idx;
897
898 vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head);
899 vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS;
900 ubuf->callback = vhost_zerocopy_callback;
901 ubuf->ctx = nvq->ubufs;
902 ubuf->desc = nvq->upend_idx;
903 refcount_set(&ubuf->refcnt, 1);
904 msg.msg_control = &ctl;
905 ctl.type = TUN_MSG_UBUF;
906 ctl.ptr = ubuf;
907 msg.msg_controllen = sizeof(ctl);
908 ubufs = nvq->ubufs;
909 atomic_inc(&ubufs->refcount);
910 nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV;
911 } else {
912 msg.msg_control = NULL;
913 ubufs = NULL;
914 }
915 total_len += len;
916 if (tx_can_batch(vq, total_len) &&
917 likely(!vhost_exceeds_maxpend(net))) {
918 msg.msg_flags |= MSG_MORE;
919 } else {
920 msg.msg_flags &= ~MSG_MORE;
921 }
922
923 /* TODO: Check specific error and bomb out unless ENOBUFS? */
924 err = sock->ops->sendmsg(sock, &msg, len);
925 if (unlikely(err < 0)) {
926 if (zcopy_used) {
927 vhost_net_ubuf_put(ubufs);
928 nvq->upend_idx = ((unsigned)nvq->upend_idx - 1)
929 % UIO_MAXIOV;
930 }
931 vhost_discard_vq_desc(vq, 1);
932 vhost_net_enable_vq(net, vq);
933 break;
934 }
935 if (err != len)
936 pr_debug("Truncated TX packet: "
937 " len %d != %zd\n", err, len);
938 if (!zcopy_used)
939 vhost_add_used_and_signal(&net->dev, vq, head, 0);
940 else
941 vhost_zerocopy_signal_used(net, vq);
942 vhost_net_tx_packet(net);
943 } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len)));
944}
945
946/* Expects to be always run from workqueue - which acts as
947 * read-size critical section for our kind of RCU. */
948static void handle_tx(struct vhost_net *net)
949{
950 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
951 struct vhost_virtqueue *vq = &nvq->vq;
952 struct socket *sock;
953
954 mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_TX);
955 sock = vq->private_data;
956 if (!sock)
957 goto out;
958
959 if (!vq_meta_prefetch(vq))
960 goto out;
961
962 vhost_disable_notify(&net->dev, vq);
963 vhost_net_disable_vq(net, vq);
964
965 if (vhost_sock_zcopy(sock))
966 handle_tx_zerocopy(net, sock);
967 else
968 handle_tx_copy(net, sock);
969
970out:
971 mutex_unlock(&vq->mutex);
972}
973
974static int peek_head_len(struct vhost_net_virtqueue *rvq, struct sock *sk)
975{
976 struct sk_buff *head;
977 int len = 0;
978 unsigned long flags;
979
980 if (rvq->rx_ring)
981 return vhost_net_buf_peek(rvq);
982
983 spin_lock_irqsave(&sk->sk_receive_queue.lock, flags);
984 head = skb_peek(&sk->sk_receive_queue);
985 if (likely(head)) {
986 len = head->len;
987 if (skb_vlan_tag_present(head))
988 len += VLAN_HLEN;
989 }
990
991 spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags);
992 return len;
993}
994
995static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk,
996 bool *busyloop_intr)
997{
998 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX];
999 struct vhost_net_virtqueue *tnvq = &net->vqs[VHOST_NET_VQ_TX];
1000 struct vhost_virtqueue *rvq = &rnvq->vq;
1001 struct vhost_virtqueue *tvq = &tnvq->vq;
1002 int len = peek_head_len(rnvq, sk);
1003
1004 if (!len && rvq->busyloop_timeout) {
1005 /* Flush batched heads first */
1006 vhost_net_signal_used(rnvq);
1007 /* Both tx vq and rx socket were polled here */
1008 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, true);
1009
1010 len = peek_head_len(rnvq, sk);
1011 }
1012
1013 return len;
1014}
1015
1016/* This is a multi-buffer version of vhost_get_desc, that works if
1017 * vq has read descriptors only.
1018 * @vq - the relevant virtqueue
1019 * @datalen - data length we'll be reading
1020 * @iovcount - returned count of io vectors we fill
1021 * @log - vhost log
1022 * @log_num - log offset
1023 * @quota - headcount quota, 1 for big buffer
1024 * returns number of buffer heads allocated, negative on error
1025 */
1026static int get_rx_bufs(struct vhost_virtqueue *vq,
1027 struct vring_used_elem *heads,
1028 int datalen,
1029 unsigned *iovcount,
1030 struct vhost_log *log,
1031 unsigned *log_num,
1032 unsigned int quota)
1033{
1034 unsigned int out, in;
1035 int seg = 0;
1036 int headcount = 0;
1037 unsigned d;
1038 int r, nlogs = 0;
1039 /* len is always initialized before use since we are always called with
1040 * datalen > 0.
1041 */
1042 u32 uninitialized_var(len);
1043
1044 while (datalen > 0 && headcount < quota) {
1045 if (unlikely(seg >= UIO_MAXIOV)) {
1046 r = -ENOBUFS;
1047 goto err;
1048 }
1049 r = vhost_get_vq_desc(vq, vq->iov + seg,
1050 ARRAY_SIZE(vq->iov) - seg, &out,
1051 &in, log, log_num);
1052 if (unlikely(r < 0))
1053 goto err;
1054
1055 d = r;
1056 if (d == vq->num) {
1057 r = 0;
1058 goto err;
1059 }
1060 if (unlikely(out || in <= 0)) {
1061 vq_err(vq, "unexpected descriptor format for RX: "
1062 "out %d, in %d\n", out, in);
1063 r = -EINVAL;
1064 goto err;
1065 }
1066 if (unlikely(log)) {
1067 nlogs += *log_num;
1068 log += *log_num;
1069 }
1070 heads[headcount].id = cpu_to_vhost32(vq, d);
1071 len = iov_length(vq->iov + seg, in);
1072 heads[headcount].len = cpu_to_vhost32(vq, len);
1073 datalen -= len;
1074 ++headcount;
1075 seg += in;
1076 }
1077 heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen);
1078 *iovcount = seg;
1079 if (unlikely(log))
1080 *log_num = nlogs;
1081
1082 /* Detect overrun */
1083 if (unlikely(datalen > 0)) {
1084 r = UIO_MAXIOV + 1;
1085 goto err;
1086 }
1087 return headcount;
1088err:
1089 vhost_discard_vq_desc(vq, headcount);
1090 return r;
1091}
1092
1093/* Expects to be always run from workqueue - which acts as
1094 * read-size critical section for our kind of RCU. */
1095static void handle_rx(struct vhost_net *net)
1096{
1097 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX];
1098 struct vhost_virtqueue *vq = &nvq->vq;
1099 unsigned uninitialized_var(in), log;
1100 struct vhost_log *vq_log;
1101 struct msghdr msg = {
1102 .msg_name = NULL,
1103 .msg_namelen = 0,
1104 .msg_control = NULL, /* FIXME: get and handle RX aux data. */
1105 .msg_controllen = 0,
1106 .msg_flags = MSG_DONTWAIT,
1107 };
1108 struct virtio_net_hdr hdr = {
1109 .flags = 0,
1110 .gso_type = VIRTIO_NET_HDR_GSO_NONE
1111 };
1112 size_t total_len = 0;
1113 int err, mergeable;
1114 s16 headcount;
1115 size_t vhost_hlen, sock_hlen;
1116 size_t vhost_len, sock_len;
1117 bool busyloop_intr = false;
1118 struct socket *sock;
1119 struct iov_iter fixup;
1120 __virtio16 num_buffers;
1121 int recv_pkts = 0;
1122
1123 mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_RX);
1124 sock = vq->private_data;
1125 if (!sock)
1126 goto out;
1127
1128 if (!vq_meta_prefetch(vq))
1129 goto out;
1130
1131 vhost_disable_notify(&net->dev, vq);
1132 vhost_net_disable_vq(net, vq);
1133
1134 vhost_hlen = nvq->vhost_hlen;
1135 sock_hlen = nvq->sock_hlen;
1136
1137 vq_log = unlikely(vhost_has_feature(vq, VHOST_F_LOG_ALL)) ?
1138 vq->log : NULL;
1139 mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF);
1140
1141 do {
1142 sock_len = vhost_net_rx_peek_head_len(net, sock->sk,
1143 &busyloop_intr);
1144 if (!sock_len)
1145 break;
1146 sock_len += sock_hlen;
1147 vhost_len = sock_len + vhost_hlen;
1148 headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx,
1149 vhost_len, &in, vq_log, &log,
1150 likely(mergeable) ? UIO_MAXIOV : 1);
1151 /* On error, stop handling until the next kick. */
1152 if (unlikely(headcount < 0))
1153 goto out;
1154 /* OK, now we need to know about added descriptors. */
1155 if (!headcount) {
1156 if (unlikely(busyloop_intr)) {
1157 vhost_poll_queue(&vq->poll);
1158 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) {
1159 /* They have slipped one in as we were
1160 * doing that: check again. */
1161 vhost_disable_notify(&net->dev, vq);
1162 continue;
1163 }
1164 /* Nothing new? Wait for eventfd to tell us
1165 * they refilled. */
1166 goto out;
1167 }
1168 busyloop_intr = false;
1169 if (nvq->rx_ring)
1170 msg.msg_control = vhost_net_buf_consume(&nvq->rxq);
1171 /* On overrun, truncate and discard */
1172 if (unlikely(headcount > UIO_MAXIOV)) {
1173 iov_iter_init(&msg.msg_iter, READ, vq->iov, 1, 1);
1174 err = sock->ops->recvmsg(sock, &msg,
1175 1, MSG_DONTWAIT | MSG_TRUNC);
1176 pr_debug("Discarded rx packet: len %zd\n", sock_len);
1177 continue;
1178 }
1179 /* We don't need to be notified again. */
1180 iov_iter_init(&msg.msg_iter, READ, vq->iov, in, vhost_len);
1181 fixup = msg.msg_iter;
1182 if (unlikely((vhost_hlen))) {
1183 /* We will supply the header ourselves
1184 * TODO: support TSO.
1185 */
1186 iov_iter_advance(&msg.msg_iter, vhost_hlen);
1187 }
1188 err = sock->ops->recvmsg(sock, &msg,
1189 sock_len, MSG_DONTWAIT | MSG_TRUNC);
1190 /* Userspace might have consumed the packet meanwhile:
1191 * it's not supposed to do this usually, but might be hard
1192 * to prevent. Discard data we got (if any) and keep going. */
1193 if (unlikely(err != sock_len)) {
1194 pr_debug("Discarded rx packet: "
1195 " len %d, expected %zd\n", err, sock_len);
1196 vhost_discard_vq_desc(vq, headcount);
1197 continue;
1198 }
1199 /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */
1200 if (unlikely(vhost_hlen)) {
1201 if (copy_to_iter(&hdr, sizeof(hdr),
1202 &fixup) != sizeof(hdr)) {
1203 vq_err(vq, "Unable to write vnet_hdr "
1204 "at addr %p\n", vq->iov->iov_base);
1205 goto out;
1206 }
1207 } else {
1208 /* Header came from socket; we'll need to patch
1209 * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF
1210 */
1211 iov_iter_advance(&fixup, sizeof(hdr));
1212 }
1213 /* TODO: Should check and handle checksum. */
1214
1215 num_buffers = cpu_to_vhost16(vq, headcount);
1216 if (likely(mergeable) &&
1217 copy_to_iter(&num_buffers, sizeof num_buffers,
1218 &fixup) != sizeof num_buffers) {
1219 vq_err(vq, "Failed num_buffers write");
1220 vhost_discard_vq_desc(vq, headcount);
1221 goto out;
1222 }
1223 nvq->done_idx += headcount;
1224 if (nvq->done_idx > VHOST_NET_BATCH)
1225 vhost_net_signal_used(nvq);
1226 if (unlikely(vq_log))
1227 vhost_log_write(vq, vq_log, log, vhost_len,
1228 vq->iov, in);
1229 total_len += vhost_len;
1230 } while (likely(!vhost_exceeds_weight(vq, ++recv_pkts, total_len)));
1231
1232 if (unlikely(busyloop_intr))
1233 vhost_poll_queue(&vq->poll);
1234 else if (!sock_len)
1235 vhost_net_enable_vq(net, vq);
1236out:
1237 vhost_net_signal_used(nvq);
1238 mutex_unlock(&vq->mutex);
1239}
1240
1241static void handle_tx_kick(struct vhost_work *work)
1242{
1243 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
1244 poll.work);
1245 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
1246
1247 handle_tx(net);
1248}
1249
1250static void handle_rx_kick(struct vhost_work *work)
1251{
1252 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
1253 poll.work);
1254 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
1255
1256 handle_rx(net);
1257}
1258
1259static void handle_tx_net(struct vhost_work *work)
1260{
1261 struct vhost_net *net = container_of(work, struct vhost_net,
1262 poll[VHOST_NET_VQ_TX].work);
1263 handle_tx(net);
1264}
1265
1266static void handle_rx_net(struct vhost_work *work)
1267{
1268 struct vhost_net *net = container_of(work, struct vhost_net,
1269 poll[VHOST_NET_VQ_RX].work);
1270 handle_rx(net);
1271}
1272
1273static int vhost_net_open(struct inode *inode, struct file *f)
1274{
1275 struct vhost_net *n;
1276 struct vhost_dev *dev;
1277 struct vhost_virtqueue **vqs;
1278 void **queue;
1279 struct xdp_buff *xdp;
1280 int i;
1281
1282 n = kvmalloc(sizeof *n, GFP_KERNEL | __GFP_RETRY_MAYFAIL);
1283 if (!n)
1284 return -ENOMEM;
1285 vqs = kmalloc_array(VHOST_NET_VQ_MAX, sizeof(*vqs), GFP_KERNEL);
1286 if (!vqs) {
1287 kvfree(n);
1288 return -ENOMEM;
1289 }
1290
1291 queue = kmalloc_array(VHOST_NET_BATCH, sizeof(void *),
1292 GFP_KERNEL);
1293 if (!queue) {
1294 kfree(vqs);
1295 kvfree(n);
1296 return -ENOMEM;
1297 }
1298 n->vqs[VHOST_NET_VQ_RX].rxq.queue = queue;
1299
1300 xdp = kmalloc_array(VHOST_NET_BATCH, sizeof(*xdp), GFP_KERNEL);
1301 if (!xdp) {
1302 kfree(vqs);
1303 kvfree(n);
1304 kfree(queue);
1305 return -ENOMEM;
1306 }
1307 n->vqs[VHOST_NET_VQ_TX].xdp = xdp;
1308
1309 dev = &n->dev;
1310 vqs[VHOST_NET_VQ_TX] = &n->vqs[VHOST_NET_VQ_TX].vq;
1311 vqs[VHOST_NET_VQ_RX] = &n->vqs[VHOST_NET_VQ_RX].vq;
1312 n->vqs[VHOST_NET_VQ_TX].vq.handle_kick = handle_tx_kick;
1313 n->vqs[VHOST_NET_VQ_RX].vq.handle_kick = handle_rx_kick;
1314 for (i = 0; i < VHOST_NET_VQ_MAX; i++) {
1315 n->vqs[i].ubufs = NULL;
1316 n->vqs[i].ubuf_info = NULL;
1317 n->vqs[i].upend_idx = 0;
1318 n->vqs[i].done_idx = 0;
1319 n->vqs[i].batched_xdp = 0;
1320 n->vqs[i].vhost_hlen = 0;
1321 n->vqs[i].sock_hlen = 0;
1322 n->vqs[i].rx_ring = NULL;
1323 vhost_net_buf_init(&n->vqs[i].rxq);
1324 }
1325 vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX,
1326 UIO_MAXIOV + VHOST_NET_BATCH,
1327 VHOST_NET_PKT_WEIGHT, VHOST_NET_WEIGHT);
1328
1329 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, EPOLLOUT, dev);
1330 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, EPOLLIN, dev);
1331
1332 f->private_data = n;
1333 n->page_frag.page = NULL;
1334 n->refcnt_bias = 0;
1335
1336 return 0;
1337}
1338
1339static struct socket *vhost_net_stop_vq(struct vhost_net *n,
1340 struct vhost_virtqueue *vq)
1341{
1342 struct socket *sock;
1343 struct vhost_net_virtqueue *nvq =
1344 container_of(vq, struct vhost_net_virtqueue, vq);
1345
1346 mutex_lock(&vq->mutex);
1347 sock = vq->private_data;
1348 vhost_net_disable_vq(n, vq);
1349 vq->private_data = NULL;
1350 vhost_net_buf_unproduce(nvq);
1351 nvq->rx_ring = NULL;
1352 mutex_unlock(&vq->mutex);
1353 return sock;
1354}
1355
1356static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock,
1357 struct socket **rx_sock)
1358{
1359 *tx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_TX].vq);
1360 *rx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_RX].vq);
1361}
1362
1363static void vhost_net_flush_vq(struct vhost_net *n, int index)
1364{
1365 vhost_poll_flush(n->poll + index);
1366 vhost_poll_flush(&n->vqs[index].vq.poll);
1367}
1368
1369static void vhost_net_flush(struct vhost_net *n)
1370{
1371 vhost_net_flush_vq(n, VHOST_NET_VQ_TX);
1372 vhost_net_flush_vq(n, VHOST_NET_VQ_RX);
1373 if (n->vqs[VHOST_NET_VQ_TX].ubufs) {
1374 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1375 n->tx_flush = true;
1376 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1377 /* Wait for all lower device DMAs done. */
1378 vhost_net_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs);
1379 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1380 n->tx_flush = false;
1381 atomic_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1);
1382 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1383 }
1384}
1385
1386static int vhost_net_release(struct inode *inode, struct file *f)
1387{
1388 struct vhost_net *n = f->private_data;
1389 struct socket *tx_sock;
1390 struct socket *rx_sock;
1391
1392 vhost_net_stop(n, &tx_sock, &rx_sock);
1393 vhost_net_flush(n);
1394 vhost_dev_stop(&n->dev);
1395 vhost_dev_cleanup(&n->dev);
1396 vhost_net_vq_reset(n);
1397 if (tx_sock)
1398 sockfd_put(tx_sock);
1399 if (rx_sock)
1400 sockfd_put(rx_sock);
1401 /* Make sure no callbacks are outstanding */
1402 synchronize_rcu();
1403 /* We do an extra flush before freeing memory,
1404 * since jobs can re-queue themselves. */
1405 vhost_net_flush(n);
1406 kfree(n->vqs[VHOST_NET_VQ_RX].rxq.queue);
1407 kfree(n->vqs[VHOST_NET_VQ_TX].xdp);
1408 kfree(n->dev.vqs);
1409 if (n->page_frag.page)
1410 __page_frag_cache_drain(n->page_frag.page, n->refcnt_bias);
1411 kvfree(n);
1412 return 0;
1413}
1414
1415static struct socket *get_raw_socket(int fd)
1416{
1417 struct {
1418 struct sockaddr_ll sa;
1419 char buf[MAX_ADDR_LEN];
1420 } uaddr;
1421 int r;
1422 struct socket *sock = sockfd_lookup(fd, &r);
1423
1424 if (!sock)
1425 return ERR_PTR(-ENOTSOCK);
1426
1427 /* Parameter checking */
1428 if (sock->sk->sk_type != SOCK_RAW) {
1429 r = -ESOCKTNOSUPPORT;
1430 goto err;
1431 }
1432
1433 r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa, 0);
1434 if (r < 0)
1435 goto err;
1436
1437 if (uaddr.sa.sll_family != AF_PACKET) {
1438 r = -EPFNOSUPPORT;
1439 goto err;
1440 }
1441 return sock;
1442err:
1443 sockfd_put(sock);
1444 return ERR_PTR(r);
1445}
1446
1447static struct ptr_ring *get_tap_ptr_ring(int fd)
1448{
1449 struct ptr_ring *ring;
1450 struct file *file = fget(fd);
1451
1452 if (!file)
1453 return NULL;
1454 ring = tun_get_tx_ring(file);
1455 if (!IS_ERR(ring))
1456 goto out;
1457 ring = tap_get_ptr_ring(file);
1458 if (!IS_ERR(ring))
1459 goto out;
1460 ring = NULL;
1461out:
1462 fput(file);
1463 return ring;
1464}
1465
1466static struct socket *get_tap_socket(int fd)
1467{
1468 struct file *file = fget(fd);
1469 struct socket *sock;
1470
1471 if (!file)
1472 return ERR_PTR(-EBADF);
1473 sock = tun_get_socket(file);
1474 if (!IS_ERR(sock))
1475 return sock;
1476 sock = tap_get_socket(file);
1477 if (IS_ERR(sock))
1478 fput(file);
1479 return sock;
1480}
1481
1482static struct socket *get_socket(int fd)
1483{
1484 struct socket *sock;
1485
1486 /* special case to disable backend */
1487 if (fd == -1)
1488 return NULL;
1489 sock = get_raw_socket(fd);
1490 if (!IS_ERR(sock))
1491 return sock;
1492 sock = get_tap_socket(fd);
1493 if (!IS_ERR(sock))
1494 return sock;
1495 return ERR_PTR(-ENOTSOCK);
1496}
1497
1498static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
1499{
1500 struct socket *sock, *oldsock;
1501 struct vhost_virtqueue *vq;
1502 struct vhost_net_virtqueue *nvq;
1503 struct vhost_net_ubuf_ref *ubufs, *oldubufs = NULL;
1504 int r;
1505
1506 mutex_lock(&n->dev.mutex);
1507 r = vhost_dev_check_owner(&n->dev);
1508 if (r)
1509 goto err;
1510
1511 if (index >= VHOST_NET_VQ_MAX) {
1512 r = -ENOBUFS;
1513 goto err;
1514 }
1515 vq = &n->vqs[index].vq;
1516 nvq = &n->vqs[index];
1517 mutex_lock(&vq->mutex);
1518
1519 /* Verify that ring has been setup correctly. */
1520 if (!vhost_vq_access_ok(vq)) {
1521 r = -EFAULT;
1522 goto err_vq;
1523 }
1524 sock = get_socket(fd);
1525 if (IS_ERR(sock)) {
1526 r = PTR_ERR(sock);
1527 goto err_vq;
1528 }
1529
1530 /* start polling new socket */
1531 oldsock = vq->private_data;
1532 if (sock != oldsock) {
1533 ubufs = vhost_net_ubuf_alloc(vq,
1534 sock && vhost_sock_zcopy(sock));
1535 if (IS_ERR(ubufs)) {
1536 r = PTR_ERR(ubufs);
1537 goto err_ubufs;
1538 }
1539
1540 vhost_net_disable_vq(n, vq);
1541 vq->private_data = sock;
1542 vhost_net_buf_unproduce(nvq);
1543 r = vhost_vq_init_access(vq);
1544 if (r)
1545 goto err_used;
1546 r = vhost_net_enable_vq(n, vq);
1547 if (r)
1548 goto err_used;
1549 if (index == VHOST_NET_VQ_RX)
1550 nvq->rx_ring = get_tap_ptr_ring(fd);
1551
1552 oldubufs = nvq->ubufs;
1553 nvq->ubufs = ubufs;
1554
1555 n->tx_packets = 0;
1556 n->tx_zcopy_err = 0;
1557 n->tx_flush = false;
1558 }
1559
1560 mutex_unlock(&vq->mutex);
1561
1562 if (oldubufs) {
1563 vhost_net_ubuf_put_wait_and_free(oldubufs);
1564 mutex_lock(&vq->mutex);
1565 vhost_zerocopy_signal_used(n, vq);
1566 mutex_unlock(&vq->mutex);
1567 }
1568
1569 if (oldsock) {
1570 vhost_net_flush_vq(n, index);
1571 sockfd_put(oldsock);
1572 }
1573
1574 mutex_unlock(&n->dev.mutex);
1575 return 0;
1576
1577err_used:
1578 vq->private_data = oldsock;
1579 vhost_net_enable_vq(n, vq);
1580 if (ubufs)
1581 vhost_net_ubuf_put_wait_and_free(ubufs);
1582err_ubufs:
1583 if (sock)
1584 sockfd_put(sock);
1585err_vq:
1586 mutex_unlock(&vq->mutex);
1587err:
1588 mutex_unlock(&n->dev.mutex);
1589 return r;
1590}
1591
1592static long vhost_net_reset_owner(struct vhost_net *n)
1593{
1594 struct socket *tx_sock = NULL;
1595 struct socket *rx_sock = NULL;
1596 long err;
1597 struct vhost_umem *umem;
1598
1599 mutex_lock(&n->dev.mutex);
1600 err = vhost_dev_check_owner(&n->dev);
1601 if (err)
1602 goto done;
1603 umem = vhost_dev_reset_owner_prepare();
1604 if (!umem) {
1605 err = -ENOMEM;
1606 goto done;
1607 }
1608 vhost_net_stop(n, &tx_sock, &rx_sock);
1609 vhost_net_flush(n);
1610 vhost_dev_stop(&n->dev);
1611 vhost_dev_reset_owner(&n->dev, umem);
1612 vhost_net_vq_reset(n);
1613done:
1614 mutex_unlock(&n->dev.mutex);
1615 if (tx_sock)
1616 sockfd_put(tx_sock);
1617 if (rx_sock)
1618 sockfd_put(rx_sock);
1619 return err;
1620}
1621
1622static int vhost_net_set_backend_features(struct vhost_net *n, u64 features)
1623{
1624 int i;
1625
1626 mutex_lock(&n->dev.mutex);
1627 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
1628 mutex_lock(&n->vqs[i].vq.mutex);
1629 n->vqs[i].vq.acked_backend_features = features;
1630 mutex_unlock(&n->vqs[i].vq.mutex);
1631 }
1632 mutex_unlock(&n->dev.mutex);
1633
1634 return 0;
1635}
1636
1637static int vhost_net_set_features(struct vhost_net *n, u64 features)
1638{
1639 size_t vhost_hlen, sock_hlen, hdr_len;
1640 int i;
1641
1642 hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) |
1643 (1ULL << VIRTIO_F_VERSION_1))) ?
1644 sizeof(struct virtio_net_hdr_mrg_rxbuf) :
1645 sizeof(struct virtio_net_hdr);
1646 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) {
1647 /* vhost provides vnet_hdr */
1648 vhost_hlen = hdr_len;
1649 sock_hlen = 0;
1650 } else {
1651 /* socket provides vnet_hdr */
1652 vhost_hlen = 0;
1653 sock_hlen = hdr_len;
1654 }
1655 mutex_lock(&n->dev.mutex);
1656 if ((features & (1 << VHOST_F_LOG_ALL)) &&
1657 !vhost_log_access_ok(&n->dev))
1658 goto out_unlock;
1659
1660 if ((features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))) {
1661 if (vhost_init_device_iotlb(&n->dev, true))
1662 goto out_unlock;
1663 }
1664
1665 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
1666 mutex_lock(&n->vqs[i].vq.mutex);
1667 n->vqs[i].vq.acked_features = features;
1668 n->vqs[i].vhost_hlen = vhost_hlen;
1669 n->vqs[i].sock_hlen = sock_hlen;
1670 mutex_unlock(&n->vqs[i].vq.mutex);
1671 }
1672 mutex_unlock(&n->dev.mutex);
1673 return 0;
1674
1675out_unlock:
1676 mutex_unlock(&n->dev.mutex);
1677 return -EFAULT;
1678}
1679
1680static long vhost_net_set_owner(struct vhost_net *n)
1681{
1682 int r;
1683
1684 mutex_lock(&n->dev.mutex);
1685 if (vhost_dev_has_owner(&n->dev)) {
1686 r = -EBUSY;
1687 goto out;
1688 }
1689 r = vhost_net_set_ubuf_info(n);
1690 if (r)
1691 goto out;
1692 r = vhost_dev_set_owner(&n->dev);
1693 if (r)
1694 vhost_net_clear_ubuf_info(n);
1695 vhost_net_flush(n);
1696out:
1697 mutex_unlock(&n->dev.mutex);
1698 return r;
1699}
1700
1701static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
1702 unsigned long arg)
1703{
1704 struct vhost_net *n = f->private_data;
1705 void __user *argp = (void __user *)arg;
1706 u64 __user *featurep = argp;
1707 struct vhost_vring_file backend;
1708 u64 features;
1709 int r;
1710
1711 switch (ioctl) {
1712 case VHOST_NET_SET_BACKEND:
1713 if (copy_from_user(&backend, argp, sizeof backend))
1714 return -EFAULT;
1715 return vhost_net_set_backend(n, backend.index, backend.fd);
1716 case VHOST_GET_FEATURES:
1717 features = VHOST_NET_FEATURES;
1718 if (copy_to_user(featurep, &features, sizeof features))
1719 return -EFAULT;
1720 return 0;
1721 case VHOST_SET_FEATURES:
1722 if (copy_from_user(&features, featurep, sizeof features))
1723 return -EFAULT;
1724 if (features & ~VHOST_NET_FEATURES)
1725 return -EOPNOTSUPP;
1726 return vhost_net_set_features(n, features);
1727 case VHOST_GET_BACKEND_FEATURES:
1728 features = VHOST_NET_BACKEND_FEATURES;
1729 if (copy_to_user(featurep, &features, sizeof(features)))
1730 return -EFAULT;
1731 return 0;
1732 case VHOST_SET_BACKEND_FEATURES:
1733 if (copy_from_user(&features, featurep, sizeof(features)))
1734 return -EFAULT;
1735 if (features & ~VHOST_NET_BACKEND_FEATURES)
1736 return -EOPNOTSUPP;
1737 return vhost_net_set_backend_features(n, features);
1738 case VHOST_RESET_OWNER:
1739 return vhost_net_reset_owner(n);
1740 case VHOST_SET_OWNER:
1741 return vhost_net_set_owner(n);
1742 default:
1743 mutex_lock(&n->dev.mutex);
1744 r = vhost_dev_ioctl(&n->dev, ioctl, argp);
1745 if (r == -ENOIOCTLCMD)
1746 r = vhost_vring_ioctl(&n->dev, ioctl, argp);
1747 else
1748 vhost_net_flush(n);
1749 mutex_unlock(&n->dev.mutex);
1750 return r;
1751 }
1752}
1753
1754#ifdef CONFIG_COMPAT
1755static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl,
1756 unsigned long arg)
1757{
1758 return vhost_net_ioctl(f, ioctl, (unsigned long)compat_ptr(arg));
1759}
1760#endif
1761
1762static ssize_t vhost_net_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1763{
1764 struct file *file = iocb->ki_filp;
1765 struct vhost_net *n = file->private_data;
1766 struct vhost_dev *dev = &n->dev;
1767 int noblock = file->f_flags & O_NONBLOCK;
1768
1769 return vhost_chr_read_iter(dev, to, noblock);
1770}
1771
1772static ssize_t vhost_net_chr_write_iter(struct kiocb *iocb,
1773 struct iov_iter *from)
1774{
1775 struct file *file = iocb->ki_filp;
1776 struct vhost_net *n = file->private_data;
1777 struct vhost_dev *dev = &n->dev;
1778
1779 return vhost_chr_write_iter(dev, from);
1780}
1781
1782static __poll_t vhost_net_chr_poll(struct file *file, poll_table *wait)
1783{
1784 struct vhost_net *n = file->private_data;
1785 struct vhost_dev *dev = &n->dev;
1786
1787 return vhost_chr_poll(file, dev, wait);
1788}
1789
1790static const struct file_operations vhost_net_fops = {
1791 .owner = THIS_MODULE,
1792 .release = vhost_net_release,
1793 .read_iter = vhost_net_chr_read_iter,
1794 .write_iter = vhost_net_chr_write_iter,
1795 .poll = vhost_net_chr_poll,
1796 .unlocked_ioctl = vhost_net_ioctl,
1797#ifdef CONFIG_COMPAT
1798 .compat_ioctl = vhost_net_compat_ioctl,
1799#endif
1800 .open = vhost_net_open,
1801 .llseek = noop_llseek,
1802};
1803
1804static struct miscdevice vhost_net_misc = {
1805 .minor = VHOST_NET_MINOR,
1806 .name = "vhost-net",
1807 .fops = &vhost_net_fops,
1808};
1809
1810static int vhost_net_init(void)
1811{
1812 if (experimental_zcopytx)
1813 vhost_net_enable_zcopy(VHOST_NET_VQ_TX);
1814 return misc_register(&vhost_net_misc);
1815}
1816module_init(vhost_net_init);
1817
1818static void vhost_net_exit(void)
1819{
1820 misc_deregister(&vhost_net_misc);
1821}
1822module_exit(vhost_net_exit);
1823
1824MODULE_VERSION("0.0.1");
1825MODULE_LICENSE("GPL v2");
1826MODULE_AUTHOR("Michael S. Tsirkin");
1827MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
1828MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR);
1829MODULE_ALIAS("devname:vhost-net");