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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 | #include <linux/if_vlan.h> |
28 | |
29 | #include <net/sock.h> |
30 | |
31 | #include "vhost.h" |
32 | |
33 | static int experimental_zcopytx; |
34 | module_param(experimental_zcopytx, int, 0444); |
35 | MODULE_PARM_DESC(experimental_zcopytx, "Enable Experimental Zero Copy TX"); |
36 | |
37 | /* Max number of bytes transferred before requeueing the job. |
38 | * Using this limit prevents one virtqueue from starving others. */ |
39 | #define VHOST_NET_WEIGHT 0x80000 |
40 | |
41 | /* MAX number of TX used buffers for outstanding zerocopy */ |
42 | #define VHOST_MAX_PEND 128 |
43 | #define VHOST_GOODCOPY_LEN 256 |
44 | |
45 | enum { |
46 | VHOST_NET_VQ_RX = 0, |
47 | VHOST_NET_VQ_TX = 1, |
48 | VHOST_NET_VQ_MAX = 2, |
49 | }; |
50 | |
51 | enum vhost_net_poll_state { |
52 | VHOST_NET_POLL_DISABLED = 0, |
53 | VHOST_NET_POLL_STARTED = 1, |
54 | VHOST_NET_POLL_STOPPED = 2, |
55 | }; |
56 | |
57 | struct vhost_net { |
58 | struct vhost_dev dev; |
59 | struct vhost_virtqueue vqs[VHOST_NET_VQ_MAX]; |
60 | struct vhost_poll poll[VHOST_NET_VQ_MAX]; |
61 | /* Tells us whether we are polling a socket for TX. |
62 | * We only do this when socket buffer fills up. |
63 | * Protected by tx vq lock. */ |
64 | enum vhost_net_poll_state tx_poll_state; |
65 | }; |
66 | |
67 | static bool vhost_sock_zcopy(struct socket *sock) |
68 | { |
69 | return unlikely(experimental_zcopytx) && |
70 | sock_flag(sock->sk, SOCK_ZEROCOPY); |
71 | } |
72 | |
73 | /* Pop first len bytes from iovec. Return number of segments used. */ |
74 | static int move_iovec_hdr(struct iovec *from, struct iovec *to, |
75 | size_t len, int iov_count) |
76 | { |
77 | int seg = 0; |
78 | size_t size; |
79 | |
80 | while (len && seg < iov_count) { |
81 | size = min(from->iov_len, len); |
82 | to->iov_base = from->iov_base; |
83 | to->iov_len = size; |
84 | from->iov_len -= size; |
85 | from->iov_base += size; |
86 | len -= size; |
87 | ++from; |
88 | ++to; |
89 | ++seg; |
90 | } |
91 | return seg; |
92 | } |
93 | /* Copy iovec entries for len bytes from iovec. */ |
94 | static void copy_iovec_hdr(const struct iovec *from, struct iovec *to, |
95 | size_t len, int iovcount) |
96 | { |
97 | int seg = 0; |
98 | size_t size; |
99 | |
100 | while (len && seg < iovcount) { |
101 | size = min(from->iov_len, len); |
102 | to->iov_base = from->iov_base; |
103 | to->iov_len = size; |
104 | len -= size; |
105 | ++from; |
106 | ++to; |
107 | ++seg; |
108 | } |
109 | } |
110 | |
111 | /* Caller must have TX VQ lock */ |
112 | static void tx_poll_stop(struct vhost_net *net) |
113 | { |
114 | if (likely(net->tx_poll_state != VHOST_NET_POLL_STARTED)) |
115 | return; |
116 | vhost_poll_stop(net->poll + VHOST_NET_VQ_TX); |
117 | net->tx_poll_state = VHOST_NET_POLL_STOPPED; |
118 | } |
119 | |
120 | /* Caller must have TX VQ lock */ |
121 | static void tx_poll_start(struct vhost_net *net, struct socket *sock) |
122 | { |
123 | if (unlikely(net->tx_poll_state != VHOST_NET_POLL_STOPPED)) |
124 | return; |
125 | vhost_poll_start(net->poll + VHOST_NET_VQ_TX, sock->file); |
126 | net->tx_poll_state = VHOST_NET_POLL_STARTED; |
127 | } |
128 | |
129 | /* Expects to be always run from workqueue - which acts as |
130 | * read-size critical section for our kind of RCU. */ |
131 | static void handle_tx(struct vhost_net *net) |
132 | { |
133 | struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_TX]; |
134 | unsigned out, in, s; |
135 | int head; |
136 | struct msghdr msg = { |
137 | .msg_name = NULL, |
138 | .msg_namelen = 0, |
139 | .msg_control = NULL, |
140 | .msg_controllen = 0, |
141 | .msg_iov = vq->iov, |
142 | .msg_flags = MSG_DONTWAIT, |
143 | }; |
144 | size_t len, total_len = 0; |
145 | int err, wmem; |
146 | size_t hdr_size; |
147 | struct socket *sock; |
148 | struct vhost_ubuf_ref *uninitialized_var(ubufs); |
149 | bool zcopy; |
150 | |
151 | /* TODO: check that we are running from vhost_worker? */ |
152 | sock = rcu_dereference_check(vq->private_data, 1); |
153 | if (!sock) |
154 | return; |
155 | |
156 | wmem = atomic_read(&sock->sk->sk_wmem_alloc); |
157 | if (wmem >= sock->sk->sk_sndbuf) { |
158 | mutex_lock(&vq->mutex); |
159 | tx_poll_start(net, sock); |
160 | mutex_unlock(&vq->mutex); |
161 | return; |
162 | } |
163 | |
164 | mutex_lock(&vq->mutex); |
165 | vhost_disable_notify(&net->dev, vq); |
166 | |
167 | if (wmem < sock->sk->sk_sndbuf / 2) |
168 | tx_poll_stop(net); |
169 | hdr_size = vq->vhost_hlen; |
170 | zcopy = vq->ubufs; |
171 | |
172 | for (;;) { |
173 | /* Release DMAs done buffers first */ |
174 | if (zcopy) |
175 | vhost_zerocopy_signal_used(vq); |
176 | |
177 | head = vhost_get_vq_desc(&net->dev, vq, vq->iov, |
178 | ARRAY_SIZE(vq->iov), |
179 | &out, &in, |
180 | NULL, NULL); |
181 | /* On error, stop handling until the next kick. */ |
182 | if (unlikely(head < 0)) |
183 | break; |
184 | /* Nothing new? Wait for eventfd to tell us they refilled. */ |
185 | if (head == vq->num) { |
186 | int num_pends; |
187 | |
188 | wmem = atomic_read(&sock->sk->sk_wmem_alloc); |
189 | if (wmem >= sock->sk->sk_sndbuf * 3 / 4) { |
190 | tx_poll_start(net, sock); |
191 | set_bit(SOCK_ASYNC_NOSPACE, &sock->flags); |
192 | break; |
193 | } |
194 | /* If more outstanding DMAs, queue the work. |
195 | * Handle upend_idx wrap around |
196 | */ |
197 | num_pends = likely(vq->upend_idx >= vq->done_idx) ? |
198 | (vq->upend_idx - vq->done_idx) : |
199 | (vq->upend_idx + UIO_MAXIOV - vq->done_idx); |
200 | if (unlikely(num_pends > VHOST_MAX_PEND)) { |
201 | tx_poll_start(net, sock); |
202 | set_bit(SOCK_ASYNC_NOSPACE, &sock->flags); |
203 | break; |
204 | } |
205 | if (unlikely(vhost_enable_notify(&net->dev, vq))) { |
206 | vhost_disable_notify(&net->dev, vq); |
207 | continue; |
208 | } |
209 | break; |
210 | } |
211 | if (in) { |
212 | vq_err(vq, "Unexpected descriptor format for TX: " |
213 | "out %d, int %d\n", out, in); |
214 | break; |
215 | } |
216 | /* Skip header. TODO: support TSO. */ |
217 | s = move_iovec_hdr(vq->iov, vq->hdr, hdr_size, out); |
218 | msg.msg_iovlen = out; |
219 | len = iov_length(vq->iov, out); |
220 | /* Sanity check */ |
221 | if (!len) { |
222 | vq_err(vq, "Unexpected header len for TX: " |
223 | "%zd expected %zd\n", |
224 | iov_length(vq->hdr, s), hdr_size); |
225 | break; |
226 | } |
227 | /* use msg_control to pass vhost zerocopy ubuf info to skb */ |
228 | if (zcopy) { |
229 | vq->heads[vq->upend_idx].id = head; |
230 | if (len < VHOST_GOODCOPY_LEN) { |
231 | /* copy don't need to wait for DMA done */ |
232 | vq->heads[vq->upend_idx].len = |
233 | VHOST_DMA_DONE_LEN; |
234 | msg.msg_control = NULL; |
235 | msg.msg_controllen = 0; |
236 | ubufs = NULL; |
237 | } else { |
238 | struct ubuf_info *ubuf = &vq->ubuf_info[head]; |
239 | |
240 | vq->heads[vq->upend_idx].len = len; |
241 | ubuf->callback = vhost_zerocopy_callback; |
242 | ubuf->ctx = vq->ubufs; |
243 | ubuf->desc = vq->upend_idx; |
244 | msg.msg_control = ubuf; |
245 | msg.msg_controllen = sizeof(ubuf); |
246 | ubufs = vq->ubufs; |
247 | kref_get(&ubufs->kref); |
248 | } |
249 | vq->upend_idx = (vq->upend_idx + 1) % UIO_MAXIOV; |
250 | } |
251 | /* TODO: Check specific error and bomb out unless ENOBUFS? */ |
252 | err = sock->ops->sendmsg(NULL, sock, &msg, len); |
253 | if (unlikely(err < 0)) { |
254 | if (zcopy) { |
255 | if (ubufs) |
256 | vhost_ubuf_put(ubufs); |
257 | vq->upend_idx = ((unsigned)vq->upend_idx - 1) % |
258 | UIO_MAXIOV; |
259 | } |
260 | vhost_discard_vq_desc(vq, 1); |
261 | if (err == -EAGAIN || err == -ENOBUFS) |
262 | tx_poll_start(net, sock); |
263 | break; |
264 | } |
265 | if (err != len) |
266 | pr_debug("Truncated TX packet: " |
267 | " len %d != %zd\n", err, len); |
268 | if (!zcopy) |
269 | vhost_add_used_and_signal(&net->dev, vq, head, 0); |
270 | else |
271 | vhost_zerocopy_signal_used(vq); |
272 | total_len += len; |
273 | if (unlikely(total_len >= VHOST_NET_WEIGHT)) { |
274 | vhost_poll_queue(&vq->poll); |
275 | break; |
276 | } |
277 | } |
278 | |
279 | mutex_unlock(&vq->mutex); |
280 | } |
281 | |
282 | static int peek_head_len(struct sock *sk) |
283 | { |
284 | struct sk_buff *head; |
285 | int len = 0; |
286 | unsigned long flags; |
287 | |
288 | spin_lock_irqsave(&sk->sk_receive_queue.lock, flags); |
289 | head = skb_peek(&sk->sk_receive_queue); |
290 | if (likely(head)) { |
291 | len = head->len; |
292 | if (vlan_tx_tag_present(head)) |
293 | len += VLAN_HLEN; |
294 | } |
295 | |
296 | spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags); |
297 | return len; |
298 | } |
299 | |
300 | /* This is a multi-buffer version of vhost_get_desc, that works if |
301 | * vq has read descriptors only. |
302 | * @vq - the relevant virtqueue |
303 | * @datalen - data length we'll be reading |
304 | * @iovcount - returned count of io vectors we fill |
305 | * @log - vhost log |
306 | * @log_num - log offset |
307 | * @quota - headcount quota, 1 for big buffer |
308 | * returns number of buffer heads allocated, negative on error |
309 | */ |
310 | static int get_rx_bufs(struct vhost_virtqueue *vq, |
311 | struct vring_used_elem *heads, |
312 | int datalen, |
313 | unsigned *iovcount, |
314 | struct vhost_log *log, |
315 | unsigned *log_num, |
316 | unsigned int quota) |
317 | { |
318 | unsigned int out, in; |
319 | int seg = 0; |
320 | int headcount = 0; |
321 | unsigned d; |
322 | int r, nlogs = 0; |
323 | |
324 | while (datalen > 0 && headcount < quota) { |
325 | if (unlikely(seg >= UIO_MAXIOV)) { |
326 | r = -ENOBUFS; |
327 | goto err; |
328 | } |
329 | d = vhost_get_vq_desc(vq->dev, vq, vq->iov + seg, |
330 | ARRAY_SIZE(vq->iov) - seg, &out, |
331 | &in, log, log_num); |
332 | if (d == vq->num) { |
333 | r = 0; |
334 | goto err; |
335 | } |
336 | if (unlikely(out || in <= 0)) { |
337 | vq_err(vq, "unexpected descriptor format for RX: " |
338 | "out %d, in %d\n", out, in); |
339 | r = -EINVAL; |
340 | goto err; |
341 | } |
342 | if (unlikely(log)) { |
343 | nlogs += *log_num; |
344 | log += *log_num; |
345 | } |
346 | heads[headcount].id = d; |
347 | heads[headcount].len = iov_length(vq->iov + seg, in); |
348 | datalen -= heads[headcount].len; |
349 | ++headcount; |
350 | seg += in; |
351 | } |
352 | heads[headcount - 1].len += datalen; |
353 | *iovcount = seg; |
354 | if (unlikely(log)) |
355 | *log_num = nlogs; |
356 | return headcount; |
357 | err: |
358 | vhost_discard_vq_desc(vq, headcount); |
359 | return r; |
360 | } |
361 | |
362 | /* Expects to be always run from workqueue - which acts as |
363 | * read-size critical section for our kind of RCU. */ |
364 | static void handle_rx(struct vhost_net *net) |
365 | { |
366 | struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX]; |
367 | unsigned uninitialized_var(in), log; |
368 | struct vhost_log *vq_log; |
369 | struct msghdr msg = { |
370 | .msg_name = NULL, |
371 | .msg_namelen = 0, |
372 | .msg_control = NULL, /* FIXME: get and handle RX aux data. */ |
373 | .msg_controllen = 0, |
374 | .msg_iov = vq->iov, |
375 | .msg_flags = MSG_DONTWAIT, |
376 | }; |
377 | struct virtio_net_hdr_mrg_rxbuf hdr = { |
378 | .hdr.flags = 0, |
379 | .hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE |
380 | }; |
381 | size_t total_len = 0; |
382 | int err, headcount, mergeable; |
383 | size_t vhost_hlen, sock_hlen; |
384 | size_t vhost_len, sock_len; |
385 | /* TODO: check that we are running from vhost_worker? */ |
386 | struct socket *sock = rcu_dereference_check(vq->private_data, 1); |
387 | |
388 | if (!sock) |
389 | return; |
390 | |
391 | mutex_lock(&vq->mutex); |
392 | vhost_disable_notify(&net->dev, vq); |
393 | vhost_hlen = vq->vhost_hlen; |
394 | sock_hlen = vq->sock_hlen; |
395 | |
396 | vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ? |
397 | vq->log : NULL; |
398 | mergeable = vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF); |
399 | |
400 | while ((sock_len = peek_head_len(sock->sk))) { |
401 | sock_len += sock_hlen; |
402 | vhost_len = sock_len + vhost_hlen; |
403 | headcount = get_rx_bufs(vq, vq->heads, vhost_len, |
404 | &in, vq_log, &log, |
405 | likely(mergeable) ? UIO_MAXIOV : 1); |
406 | /* On error, stop handling until the next kick. */ |
407 | if (unlikely(headcount < 0)) |
408 | break; |
409 | /* OK, now we need to know about added descriptors. */ |
410 | if (!headcount) { |
411 | if (unlikely(vhost_enable_notify(&net->dev, vq))) { |
412 | /* They have slipped one in as we were |
413 | * doing that: check again. */ |
414 | vhost_disable_notify(&net->dev, vq); |
415 | continue; |
416 | } |
417 | /* Nothing new? Wait for eventfd to tell us |
418 | * they refilled. */ |
419 | break; |
420 | } |
421 | /* We don't need to be notified again. */ |
422 | if (unlikely((vhost_hlen))) |
423 | /* Skip header. TODO: support TSO. */ |
424 | move_iovec_hdr(vq->iov, vq->hdr, vhost_hlen, in); |
425 | else |
426 | /* Copy the header for use in VIRTIO_NET_F_MRG_RXBUF: |
427 | * needed because recvmsg can modify msg_iov. */ |
428 | copy_iovec_hdr(vq->iov, vq->hdr, sock_hlen, in); |
429 | msg.msg_iovlen = in; |
430 | err = sock->ops->recvmsg(NULL, sock, &msg, |
431 | sock_len, MSG_DONTWAIT | MSG_TRUNC); |
432 | /* Userspace might have consumed the packet meanwhile: |
433 | * it's not supposed to do this usually, but might be hard |
434 | * to prevent. Discard data we got (if any) and keep going. */ |
435 | if (unlikely(err != sock_len)) { |
436 | pr_debug("Discarded rx packet: " |
437 | " len %d, expected %zd\n", err, sock_len); |
438 | vhost_discard_vq_desc(vq, headcount); |
439 | continue; |
440 | } |
441 | if (unlikely(vhost_hlen) && |
442 | memcpy_toiovecend(vq->hdr, (unsigned char *)&hdr, 0, |
443 | vhost_hlen)) { |
444 | vq_err(vq, "Unable to write vnet_hdr at addr %p\n", |
445 | vq->iov->iov_base); |
446 | break; |
447 | } |
448 | /* TODO: Should check and handle checksum. */ |
449 | if (likely(mergeable) && |
450 | memcpy_toiovecend(vq->hdr, (unsigned char *)&headcount, |
451 | offsetof(typeof(hdr), num_buffers), |
452 | sizeof hdr.num_buffers)) { |
453 | vq_err(vq, "Failed num_buffers write"); |
454 | vhost_discard_vq_desc(vq, headcount); |
455 | break; |
456 | } |
457 | vhost_add_used_and_signal_n(&net->dev, vq, vq->heads, |
458 | headcount); |
459 | if (unlikely(vq_log)) |
460 | vhost_log_write(vq, vq_log, log, vhost_len); |
461 | total_len += vhost_len; |
462 | if (unlikely(total_len >= VHOST_NET_WEIGHT)) { |
463 | vhost_poll_queue(&vq->poll); |
464 | break; |
465 | } |
466 | } |
467 | |
468 | mutex_unlock(&vq->mutex); |
469 | } |
470 | |
471 | static void handle_tx_kick(struct vhost_work *work) |
472 | { |
473 | struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, |
474 | poll.work); |
475 | struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); |
476 | |
477 | handle_tx(net); |
478 | } |
479 | |
480 | static void handle_rx_kick(struct vhost_work *work) |
481 | { |
482 | struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, |
483 | poll.work); |
484 | struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); |
485 | |
486 | handle_rx(net); |
487 | } |
488 | |
489 | static void handle_tx_net(struct vhost_work *work) |
490 | { |
491 | struct vhost_net *net = container_of(work, struct vhost_net, |
492 | poll[VHOST_NET_VQ_TX].work); |
493 | handle_tx(net); |
494 | } |
495 | |
496 | static void handle_rx_net(struct vhost_work *work) |
497 | { |
498 | struct vhost_net *net = container_of(work, struct vhost_net, |
499 | poll[VHOST_NET_VQ_RX].work); |
500 | handle_rx(net); |
501 | } |
502 | |
503 | static int vhost_net_open(struct inode *inode, struct file *f) |
504 | { |
505 | struct vhost_net *n = kmalloc(sizeof *n, GFP_KERNEL); |
506 | struct vhost_dev *dev; |
507 | int r; |
508 | |
509 | if (!n) |
510 | return -ENOMEM; |
511 | |
512 | dev = &n->dev; |
513 | n->vqs[VHOST_NET_VQ_TX].handle_kick = handle_tx_kick; |
514 | n->vqs[VHOST_NET_VQ_RX].handle_kick = handle_rx_kick; |
515 | r = vhost_dev_init(dev, n->vqs, VHOST_NET_VQ_MAX); |
516 | if (r < 0) { |
517 | kfree(n); |
518 | return r; |
519 | } |
520 | |
521 | vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT, dev); |
522 | vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN, dev); |
523 | n->tx_poll_state = VHOST_NET_POLL_DISABLED; |
524 | |
525 | f->private_data = n; |
526 | |
527 | return 0; |
528 | } |
529 | |
530 | static void vhost_net_disable_vq(struct vhost_net *n, |
531 | struct vhost_virtqueue *vq) |
532 | { |
533 | if (!vq->private_data) |
534 | return; |
535 | if (vq == n->vqs + VHOST_NET_VQ_TX) { |
536 | tx_poll_stop(n); |
537 | n->tx_poll_state = VHOST_NET_POLL_DISABLED; |
538 | } else |
539 | vhost_poll_stop(n->poll + VHOST_NET_VQ_RX); |
540 | } |
541 | |
542 | static void vhost_net_enable_vq(struct vhost_net *n, |
543 | struct vhost_virtqueue *vq) |
544 | { |
545 | struct socket *sock; |
546 | |
547 | sock = rcu_dereference_protected(vq->private_data, |
548 | lockdep_is_held(&vq->mutex)); |
549 | if (!sock) |
550 | return; |
551 | if (vq == n->vqs + VHOST_NET_VQ_TX) { |
552 | n->tx_poll_state = VHOST_NET_POLL_STOPPED; |
553 | tx_poll_start(n, sock); |
554 | } else |
555 | vhost_poll_start(n->poll + VHOST_NET_VQ_RX, sock->file); |
556 | } |
557 | |
558 | static struct socket *vhost_net_stop_vq(struct vhost_net *n, |
559 | struct vhost_virtqueue *vq) |
560 | { |
561 | struct socket *sock; |
562 | |
563 | mutex_lock(&vq->mutex); |
564 | sock = rcu_dereference_protected(vq->private_data, |
565 | lockdep_is_held(&vq->mutex)); |
566 | vhost_net_disable_vq(n, vq); |
567 | rcu_assign_pointer(vq->private_data, NULL); |
568 | mutex_unlock(&vq->mutex); |
569 | return sock; |
570 | } |
571 | |
572 | static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock, |
573 | struct socket **rx_sock) |
574 | { |
575 | *tx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_TX); |
576 | *rx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_RX); |
577 | } |
578 | |
579 | static void vhost_net_flush_vq(struct vhost_net *n, int index) |
580 | { |
581 | vhost_poll_flush(n->poll + index); |
582 | vhost_poll_flush(&n->dev.vqs[index].poll); |
583 | } |
584 | |
585 | static void vhost_net_flush(struct vhost_net *n) |
586 | { |
587 | vhost_net_flush_vq(n, VHOST_NET_VQ_TX); |
588 | vhost_net_flush_vq(n, VHOST_NET_VQ_RX); |
589 | } |
590 | |
591 | static int vhost_net_release(struct inode *inode, struct file *f) |
592 | { |
593 | struct vhost_net *n = f->private_data; |
594 | struct socket *tx_sock; |
595 | struct socket *rx_sock; |
596 | |
597 | vhost_net_stop(n, &tx_sock, &rx_sock); |
598 | vhost_net_flush(n); |
599 | vhost_dev_cleanup(&n->dev, false); |
600 | if (tx_sock) |
601 | fput(tx_sock->file); |
602 | if (rx_sock) |
603 | fput(rx_sock->file); |
604 | /* We do an extra flush before freeing memory, |
605 | * since jobs can re-queue themselves. */ |
606 | vhost_net_flush(n); |
607 | kfree(n); |
608 | return 0; |
609 | } |
610 | |
611 | static struct socket *get_raw_socket(int fd) |
612 | { |
613 | struct { |
614 | struct sockaddr_ll sa; |
615 | char buf[MAX_ADDR_LEN]; |
616 | } uaddr; |
617 | int uaddr_len = sizeof uaddr, r; |
618 | struct socket *sock = sockfd_lookup(fd, &r); |
619 | |
620 | if (!sock) |
621 | return ERR_PTR(-ENOTSOCK); |
622 | |
623 | /* Parameter checking */ |
624 | if (sock->sk->sk_type != SOCK_RAW) { |
625 | r = -ESOCKTNOSUPPORT; |
626 | goto err; |
627 | } |
628 | |
629 | r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa, |
630 | &uaddr_len, 0); |
631 | if (r) |
632 | goto err; |
633 | |
634 | if (uaddr.sa.sll_family != AF_PACKET) { |
635 | r = -EPFNOSUPPORT; |
636 | goto err; |
637 | } |
638 | return sock; |
639 | err: |
640 | fput(sock->file); |
641 | return ERR_PTR(r); |
642 | } |
643 | |
644 | static struct socket *get_tap_socket(int fd) |
645 | { |
646 | struct file *file = fget(fd); |
647 | struct socket *sock; |
648 | |
649 | if (!file) |
650 | return ERR_PTR(-EBADF); |
651 | sock = tun_get_socket(file); |
652 | if (!IS_ERR(sock)) |
653 | return sock; |
654 | sock = macvtap_get_socket(file); |
655 | if (IS_ERR(sock)) |
656 | fput(file); |
657 | return sock; |
658 | } |
659 | |
660 | static struct socket *get_socket(int fd) |
661 | { |
662 | struct socket *sock; |
663 | |
664 | /* special case to disable backend */ |
665 | if (fd == -1) |
666 | return NULL; |
667 | sock = get_raw_socket(fd); |
668 | if (!IS_ERR(sock)) |
669 | return sock; |
670 | sock = get_tap_socket(fd); |
671 | if (!IS_ERR(sock)) |
672 | return sock; |
673 | return ERR_PTR(-ENOTSOCK); |
674 | } |
675 | |
676 | static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) |
677 | { |
678 | struct socket *sock, *oldsock; |
679 | struct vhost_virtqueue *vq; |
680 | struct vhost_ubuf_ref *ubufs, *oldubufs = NULL; |
681 | int r; |
682 | |
683 | mutex_lock(&n->dev.mutex); |
684 | r = vhost_dev_check_owner(&n->dev); |
685 | if (r) |
686 | goto err; |
687 | |
688 | if (index >= VHOST_NET_VQ_MAX) { |
689 | r = -ENOBUFS; |
690 | goto err; |
691 | } |
692 | vq = n->vqs + index; |
693 | mutex_lock(&vq->mutex); |
694 | |
695 | /* Verify that ring has been setup correctly. */ |
696 | if (!vhost_vq_access_ok(vq)) { |
697 | r = -EFAULT; |
698 | goto err_vq; |
699 | } |
700 | sock = get_socket(fd); |
701 | if (IS_ERR(sock)) { |
702 | r = PTR_ERR(sock); |
703 | goto err_vq; |
704 | } |
705 | |
706 | /* start polling new socket */ |
707 | oldsock = rcu_dereference_protected(vq->private_data, |
708 | lockdep_is_held(&vq->mutex)); |
709 | if (sock != oldsock) { |
710 | ubufs = vhost_ubuf_alloc(vq, sock && vhost_sock_zcopy(sock)); |
711 | if (IS_ERR(ubufs)) { |
712 | r = PTR_ERR(ubufs); |
713 | goto err_ubufs; |
714 | } |
715 | oldubufs = vq->ubufs; |
716 | vq->ubufs = ubufs; |
717 | vhost_net_disable_vq(n, vq); |
718 | rcu_assign_pointer(vq->private_data, sock); |
719 | vhost_net_enable_vq(n, vq); |
720 | |
721 | r = vhost_init_used(vq); |
722 | if (r) |
723 | goto err_vq; |
724 | } |
725 | |
726 | mutex_unlock(&vq->mutex); |
727 | |
728 | if (oldubufs) { |
729 | vhost_ubuf_put_and_wait(oldubufs); |
730 | mutex_lock(&vq->mutex); |
731 | vhost_zerocopy_signal_used(vq); |
732 | mutex_unlock(&vq->mutex); |
733 | } |
734 | |
735 | if (oldsock) { |
736 | vhost_net_flush_vq(n, index); |
737 | fput(oldsock->file); |
738 | } |
739 | |
740 | mutex_unlock(&n->dev.mutex); |
741 | return 0; |
742 | |
743 | err_ubufs: |
744 | fput(sock->file); |
745 | err_vq: |
746 | mutex_unlock(&vq->mutex); |
747 | err: |
748 | mutex_unlock(&n->dev.mutex); |
749 | return r; |
750 | } |
751 | |
752 | static long vhost_net_reset_owner(struct vhost_net *n) |
753 | { |
754 | struct socket *tx_sock = NULL; |
755 | struct socket *rx_sock = NULL; |
756 | long err; |
757 | |
758 | mutex_lock(&n->dev.mutex); |
759 | err = vhost_dev_check_owner(&n->dev); |
760 | if (err) |
761 | goto done; |
762 | vhost_net_stop(n, &tx_sock, &rx_sock); |
763 | vhost_net_flush(n); |
764 | err = vhost_dev_reset_owner(&n->dev); |
765 | done: |
766 | mutex_unlock(&n->dev.mutex); |
767 | if (tx_sock) |
768 | fput(tx_sock->file); |
769 | if (rx_sock) |
770 | fput(rx_sock->file); |
771 | return err; |
772 | } |
773 | |
774 | static int vhost_net_set_features(struct vhost_net *n, u64 features) |
775 | { |
776 | size_t vhost_hlen, sock_hlen, hdr_len; |
777 | int i; |
778 | |
779 | hdr_len = (features & (1 << VIRTIO_NET_F_MRG_RXBUF)) ? |
780 | sizeof(struct virtio_net_hdr_mrg_rxbuf) : |
781 | sizeof(struct virtio_net_hdr); |
782 | if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) { |
783 | /* vhost provides vnet_hdr */ |
784 | vhost_hlen = hdr_len; |
785 | sock_hlen = 0; |
786 | } else { |
787 | /* socket provides vnet_hdr */ |
788 | vhost_hlen = 0; |
789 | sock_hlen = hdr_len; |
790 | } |
791 | mutex_lock(&n->dev.mutex); |
792 | if ((features & (1 << VHOST_F_LOG_ALL)) && |
793 | !vhost_log_access_ok(&n->dev)) { |
794 | mutex_unlock(&n->dev.mutex); |
795 | return -EFAULT; |
796 | } |
797 | n->dev.acked_features = features; |
798 | smp_wmb(); |
799 | for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { |
800 | mutex_lock(&n->vqs[i].mutex); |
801 | n->vqs[i].vhost_hlen = vhost_hlen; |
802 | n->vqs[i].sock_hlen = sock_hlen; |
803 | mutex_unlock(&n->vqs[i].mutex); |
804 | } |
805 | vhost_net_flush(n); |
806 | mutex_unlock(&n->dev.mutex); |
807 | return 0; |
808 | } |
809 | |
810 | static long vhost_net_ioctl(struct file *f, unsigned int ioctl, |
811 | unsigned long arg) |
812 | { |
813 | struct vhost_net *n = f->private_data; |
814 | void __user *argp = (void __user *)arg; |
815 | u64 __user *featurep = argp; |
816 | struct vhost_vring_file backend; |
817 | u64 features; |
818 | int r; |
819 | |
820 | switch (ioctl) { |
821 | case VHOST_NET_SET_BACKEND: |
822 | if (copy_from_user(&backend, argp, sizeof backend)) |
823 | return -EFAULT; |
824 | return vhost_net_set_backend(n, backend.index, backend.fd); |
825 | case VHOST_GET_FEATURES: |
826 | features = VHOST_NET_FEATURES; |
827 | if (copy_to_user(featurep, &features, sizeof features)) |
828 | return -EFAULT; |
829 | return 0; |
830 | case VHOST_SET_FEATURES: |
831 | if (copy_from_user(&features, featurep, sizeof features)) |
832 | return -EFAULT; |
833 | if (features & ~VHOST_NET_FEATURES) |
834 | return -EOPNOTSUPP; |
835 | return vhost_net_set_features(n, features); |
836 | case VHOST_RESET_OWNER: |
837 | return vhost_net_reset_owner(n); |
838 | default: |
839 | mutex_lock(&n->dev.mutex); |
840 | r = vhost_dev_ioctl(&n->dev, ioctl, arg); |
841 | vhost_net_flush(n); |
842 | mutex_unlock(&n->dev.mutex); |
843 | return r; |
844 | } |
845 | } |
846 | |
847 | #ifdef CONFIG_COMPAT |
848 | static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl, |
849 | unsigned long arg) |
850 | { |
851 | return vhost_net_ioctl(f, ioctl, (unsigned long)compat_ptr(arg)); |
852 | } |
853 | #endif |
854 | |
855 | static const struct file_operations vhost_net_fops = { |
856 | .owner = THIS_MODULE, |
857 | .release = vhost_net_release, |
858 | .unlocked_ioctl = vhost_net_ioctl, |
859 | #ifdef CONFIG_COMPAT |
860 | .compat_ioctl = vhost_net_compat_ioctl, |
861 | #endif |
862 | .open = vhost_net_open, |
863 | .llseek = noop_llseek, |
864 | }; |
865 | |
866 | static struct miscdevice vhost_net_misc = { |
867 | .minor = VHOST_NET_MINOR, |
868 | .name = "vhost-net", |
869 | .fops = &vhost_net_fops, |
870 | }; |
871 | |
872 | static int vhost_net_init(void) |
873 | { |
874 | if (experimental_zcopytx) |
875 | vhost_enable_zcopy(VHOST_NET_VQ_TX); |
876 | return misc_register(&vhost_net_misc); |
877 | } |
878 | module_init(vhost_net_init); |
879 | |
880 | static void vhost_net_exit(void) |
881 | { |
882 | misc_deregister(&vhost_net_misc); |
883 | } |
884 | module_exit(vhost_net_exit); |
885 | |
886 | MODULE_VERSION("0.0.1"); |
887 | MODULE_LICENSE("GPL v2"); |
888 | MODULE_AUTHOR("Michael S. Tsirkin"); |
889 | MODULE_DESCRIPTION("Host kernel accelerator for virtio net"); |
890 | MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR); |
891 | MODULE_ALIAS("devname:vhost-net"); |
892 |
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Tags:
od-2011-09-04
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v2.6.34-rc5
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