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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 = 1; |
34 | module_param(experimental_zcopytx, int, 0444); |
35 | MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;" |
36 | " 1 -Enable; 0 - Disable"); |
37 | |
38 | /* Max number of bytes transferred before requeueing the job. |
39 | * Using this limit prevents one virtqueue from starving others. */ |
40 | #define VHOST_NET_WEIGHT 0x80000 |
41 | |
42 | /* MAX number of TX used buffers for outstanding zerocopy */ |
43 | #define VHOST_MAX_PEND 128 |
44 | #define VHOST_GOODCOPY_LEN 256 |
45 | |
46 | /* |
47 | * For transmit, used buffer len is unused; we override it to track buffer |
48 | * status internally; used for zerocopy tx only. |
49 | */ |
50 | /* Lower device DMA failed */ |
51 | #define VHOST_DMA_FAILED_LEN 3 |
52 | /* Lower device DMA done */ |
53 | #define VHOST_DMA_DONE_LEN 2 |
54 | /* Lower device DMA in progress */ |
55 | #define VHOST_DMA_IN_PROGRESS 1 |
56 | /* Buffer unused */ |
57 | #define VHOST_DMA_CLEAR_LEN 0 |
58 | |
59 | #define VHOST_DMA_IS_DONE(len) ((len) >= VHOST_DMA_DONE_LEN) |
60 | |
61 | enum { |
62 | VHOST_NET_VQ_RX = 0, |
63 | VHOST_NET_VQ_TX = 1, |
64 | VHOST_NET_VQ_MAX = 2, |
65 | }; |
66 | |
67 | enum vhost_net_poll_state { |
68 | VHOST_NET_POLL_DISABLED = 0, |
69 | VHOST_NET_POLL_STARTED = 1, |
70 | VHOST_NET_POLL_STOPPED = 2, |
71 | }; |
72 | |
73 | struct vhost_net { |
74 | struct vhost_dev dev; |
75 | struct vhost_virtqueue vqs[VHOST_NET_VQ_MAX]; |
76 | struct vhost_poll poll[VHOST_NET_VQ_MAX]; |
77 | /* Tells us whether we are polling a socket for TX. |
78 | * We only do this when socket buffer fills up. |
79 | * Protected by tx vq lock. */ |
80 | enum vhost_net_poll_state tx_poll_state; |
81 | /* Number of TX recently submitted. |
82 | * Protected by tx vq lock. */ |
83 | unsigned tx_packets; |
84 | /* Number of times zerocopy TX recently failed. |
85 | * Protected by tx vq lock. */ |
86 | unsigned tx_zcopy_err; |
87 | /* Flush in progress. Protected by tx vq lock. */ |
88 | bool tx_flush; |
89 | }; |
90 | |
91 | static void vhost_net_tx_packet(struct vhost_net *net) |
92 | { |
93 | ++net->tx_packets; |
94 | if (net->tx_packets < 1024) |
95 | return; |
96 | net->tx_packets = 0; |
97 | net->tx_zcopy_err = 0; |
98 | } |
99 | |
100 | static void vhost_net_tx_err(struct vhost_net *net) |
101 | { |
102 | ++net->tx_zcopy_err; |
103 | } |
104 | |
105 | static bool vhost_net_tx_select_zcopy(struct vhost_net *net) |
106 | { |
107 | /* TX flush waits for outstanding DMAs to be done. |
108 | * Don't start new DMAs. |
109 | */ |
110 | return !net->tx_flush && |
111 | net->tx_packets / 64 >= net->tx_zcopy_err; |
112 | } |
113 | |
114 | static bool vhost_sock_zcopy(struct socket *sock) |
115 | { |
116 | return unlikely(experimental_zcopytx) && |
117 | sock_flag(sock->sk, SOCK_ZEROCOPY); |
118 | } |
119 | |
120 | /* Pop first len bytes from iovec. Return number of segments used. */ |
121 | static int move_iovec_hdr(struct iovec *from, struct iovec *to, |
122 | size_t len, int iov_count) |
123 | { |
124 | int seg = 0; |
125 | size_t size; |
126 | |
127 | while (len && seg < iov_count) { |
128 | size = min(from->iov_len, len); |
129 | to->iov_base = from->iov_base; |
130 | to->iov_len = size; |
131 | from->iov_len -= size; |
132 | from->iov_base += size; |
133 | len -= size; |
134 | ++from; |
135 | ++to; |
136 | ++seg; |
137 | } |
138 | return seg; |
139 | } |
140 | /* Copy iovec entries for len bytes from iovec. */ |
141 | static void copy_iovec_hdr(const struct iovec *from, struct iovec *to, |
142 | size_t len, int iovcount) |
143 | { |
144 | int seg = 0; |
145 | size_t size; |
146 | |
147 | while (len && seg < iovcount) { |
148 | size = min(from->iov_len, len); |
149 | to->iov_base = from->iov_base; |
150 | to->iov_len = size; |
151 | len -= size; |
152 | ++from; |
153 | ++to; |
154 | ++seg; |
155 | } |
156 | } |
157 | |
158 | /* Caller must have TX VQ lock */ |
159 | static void tx_poll_stop(struct vhost_net *net) |
160 | { |
161 | if (likely(net->tx_poll_state != VHOST_NET_POLL_STARTED)) |
162 | return; |
163 | vhost_poll_stop(net->poll + VHOST_NET_VQ_TX); |
164 | net->tx_poll_state = VHOST_NET_POLL_STOPPED; |
165 | } |
166 | |
167 | /* Caller must have TX VQ lock */ |
168 | static int tx_poll_start(struct vhost_net *net, struct socket *sock) |
169 | { |
170 | int ret; |
171 | |
172 | if (unlikely(net->tx_poll_state != VHOST_NET_POLL_STOPPED)) |
173 | return 0; |
174 | ret = vhost_poll_start(net->poll + VHOST_NET_VQ_TX, sock->file); |
175 | if (!ret) |
176 | net->tx_poll_state = VHOST_NET_POLL_STARTED; |
177 | return ret; |
178 | } |
179 | |
180 | /* In case of DMA done not in order in lower device driver for some reason. |
181 | * upend_idx is used to track end of used idx, done_idx is used to track head |
182 | * of used idx. Once lower device DMA done contiguously, we will signal KVM |
183 | * guest used idx. |
184 | */ |
185 | static int vhost_zerocopy_signal_used(struct vhost_net *net, |
186 | struct vhost_virtqueue *vq) |
187 | { |
188 | int i; |
189 | int j = 0; |
190 | |
191 | for (i = vq->done_idx; i != vq->upend_idx; i = (i + 1) % UIO_MAXIOV) { |
192 | if (vq->heads[i].len == VHOST_DMA_FAILED_LEN) |
193 | vhost_net_tx_err(net); |
194 | if (VHOST_DMA_IS_DONE(vq->heads[i].len)) { |
195 | vq->heads[i].len = VHOST_DMA_CLEAR_LEN; |
196 | vhost_add_used_and_signal(vq->dev, vq, |
197 | vq->heads[i].id, 0); |
198 | ++j; |
199 | } else |
200 | break; |
201 | } |
202 | if (j) |
203 | vq->done_idx = i; |
204 | return j; |
205 | } |
206 | |
207 | static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) |
208 | { |
209 | struct vhost_ubuf_ref *ubufs = ubuf->ctx; |
210 | struct vhost_virtqueue *vq = ubufs->vq; |
211 | int cnt = atomic_read(&ubufs->kref.refcount); |
212 | |
213 | /* |
214 | * Trigger polling thread if guest stopped submitting new buffers: |
215 | * in this case, the refcount after decrement will eventually reach 1 |
216 | * so here it is 2. |
217 | * We also trigger polling periodically after each 16 packets |
218 | * (the value 16 here is more or less arbitrary, it's tuned to trigger |
219 | * less than 10% of times). |
220 | */ |
221 | if (cnt <= 2 || !(cnt % 16)) |
222 | vhost_poll_queue(&vq->poll); |
223 | /* set len to mark this desc buffers done DMA */ |
224 | vq->heads[ubuf->desc].len = success ? |
225 | VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; |
226 | vhost_ubuf_put(ubufs); |
227 | } |
228 | |
229 | /* Expects to be always run from workqueue - which acts as |
230 | * read-size critical section for our kind of RCU. */ |
231 | static void handle_tx(struct vhost_net *net) |
232 | { |
233 | struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_TX]; |
234 | unsigned out, in, s; |
235 | int head; |
236 | struct msghdr msg = { |
237 | .msg_name = NULL, |
238 | .msg_namelen = 0, |
239 | .msg_control = NULL, |
240 | .msg_controllen = 0, |
241 | .msg_iov = vq->iov, |
242 | .msg_flags = MSG_DONTWAIT, |
243 | }; |
244 | size_t len, total_len = 0; |
245 | int err, wmem; |
246 | size_t hdr_size; |
247 | struct socket *sock; |
248 | struct vhost_ubuf_ref *uninitialized_var(ubufs); |
249 | bool zcopy, zcopy_used; |
250 | |
251 | /* TODO: check that we are running from vhost_worker? */ |
252 | sock = rcu_dereference_check(vq->private_data, 1); |
253 | if (!sock) |
254 | return; |
255 | |
256 | wmem = atomic_read(&sock->sk->sk_wmem_alloc); |
257 | if (wmem >= sock->sk->sk_sndbuf) { |
258 | mutex_lock(&vq->mutex); |
259 | tx_poll_start(net, sock); |
260 | mutex_unlock(&vq->mutex); |
261 | return; |
262 | } |
263 | |
264 | mutex_lock(&vq->mutex); |
265 | vhost_disable_notify(&net->dev, vq); |
266 | |
267 | if (wmem < sock->sk->sk_sndbuf / 2) |
268 | tx_poll_stop(net); |
269 | hdr_size = vq->vhost_hlen; |
270 | zcopy = vq->ubufs; |
271 | |
272 | for (;;) { |
273 | /* Release DMAs done buffers first */ |
274 | if (zcopy) |
275 | vhost_zerocopy_signal_used(net, vq); |
276 | |
277 | head = vhost_get_vq_desc(&net->dev, vq, vq->iov, |
278 | ARRAY_SIZE(vq->iov), |
279 | &out, &in, |
280 | NULL, NULL); |
281 | /* On error, stop handling until the next kick. */ |
282 | if (unlikely(head < 0)) |
283 | break; |
284 | /* Nothing new? Wait for eventfd to tell us they refilled. */ |
285 | if (head == vq->num) { |
286 | int num_pends; |
287 | |
288 | wmem = atomic_read(&sock->sk->sk_wmem_alloc); |
289 | if (wmem >= sock->sk->sk_sndbuf * 3 / 4) { |
290 | tx_poll_start(net, sock); |
291 | set_bit(SOCK_ASYNC_NOSPACE, &sock->flags); |
292 | break; |
293 | } |
294 | /* If more outstanding DMAs, queue the work. |
295 | * Handle upend_idx wrap around |
296 | */ |
297 | num_pends = likely(vq->upend_idx >= vq->done_idx) ? |
298 | (vq->upend_idx - vq->done_idx) : |
299 | (vq->upend_idx + UIO_MAXIOV - vq->done_idx); |
300 | if (unlikely(num_pends > VHOST_MAX_PEND)) { |
301 | tx_poll_start(net, sock); |
302 | set_bit(SOCK_ASYNC_NOSPACE, &sock->flags); |
303 | break; |
304 | } |
305 | if (unlikely(vhost_enable_notify(&net->dev, vq))) { |
306 | vhost_disable_notify(&net->dev, vq); |
307 | continue; |
308 | } |
309 | break; |
310 | } |
311 | if (in) { |
312 | vq_err(vq, "Unexpected descriptor format for TX: " |
313 | "out %d, int %d\n", out, in); |
314 | break; |
315 | } |
316 | /* Skip header. TODO: support TSO. */ |
317 | s = move_iovec_hdr(vq->iov, vq->hdr, hdr_size, out); |
318 | msg.msg_iovlen = out; |
319 | len = iov_length(vq->iov, out); |
320 | /* Sanity check */ |
321 | if (!len) { |
322 | vq_err(vq, "Unexpected header len for TX: " |
323 | "%zd expected %zd\n", |
324 | iov_length(vq->hdr, s), hdr_size); |
325 | break; |
326 | } |
327 | zcopy_used = zcopy && (len >= VHOST_GOODCOPY_LEN || |
328 | vq->upend_idx != vq->done_idx); |
329 | |
330 | /* use msg_control to pass vhost zerocopy ubuf info to skb */ |
331 | if (zcopy_used) { |
332 | vq->heads[vq->upend_idx].id = head; |
333 | if (!vhost_net_tx_select_zcopy(net) || |
334 | len < VHOST_GOODCOPY_LEN) { |
335 | /* copy don't need to wait for DMA done */ |
336 | vq->heads[vq->upend_idx].len = |
337 | VHOST_DMA_DONE_LEN; |
338 | msg.msg_control = NULL; |
339 | msg.msg_controllen = 0; |
340 | ubufs = NULL; |
341 | } else { |
342 | struct ubuf_info *ubuf; |
343 | ubuf = vq->ubuf_info + vq->upend_idx; |
344 | |
345 | vq->heads[vq->upend_idx].len = |
346 | VHOST_DMA_IN_PROGRESS; |
347 | ubuf->callback = vhost_zerocopy_callback; |
348 | ubuf->ctx = vq->ubufs; |
349 | ubuf->desc = vq->upend_idx; |
350 | msg.msg_control = ubuf; |
351 | msg.msg_controllen = sizeof(ubuf); |
352 | ubufs = vq->ubufs; |
353 | kref_get(&ubufs->kref); |
354 | } |
355 | vq->upend_idx = (vq->upend_idx + 1) % UIO_MAXIOV; |
356 | } |
357 | /* TODO: Check specific error and bomb out unless ENOBUFS? */ |
358 | err = sock->ops->sendmsg(NULL, sock, &msg, len); |
359 | if (unlikely(err < 0)) { |
360 | if (zcopy_used) { |
361 | if (ubufs) |
362 | vhost_ubuf_put(ubufs); |
363 | vq->upend_idx = ((unsigned)vq->upend_idx - 1) % |
364 | UIO_MAXIOV; |
365 | } |
366 | vhost_discard_vq_desc(vq, 1); |
367 | if (err == -EAGAIN || err == -ENOBUFS) |
368 | tx_poll_start(net, sock); |
369 | break; |
370 | } |
371 | if (err != len) |
372 | pr_debug("Truncated TX packet: " |
373 | " len %d != %zd\n", err, len); |
374 | if (!zcopy_used) |
375 | vhost_add_used_and_signal(&net->dev, vq, head, 0); |
376 | else |
377 | vhost_zerocopy_signal_used(net, vq); |
378 | total_len += len; |
379 | vhost_net_tx_packet(net); |
380 | if (unlikely(total_len >= VHOST_NET_WEIGHT)) { |
381 | vhost_poll_queue(&vq->poll); |
382 | break; |
383 | } |
384 | } |
385 | |
386 | mutex_unlock(&vq->mutex); |
387 | } |
388 | |
389 | static int peek_head_len(struct sock *sk) |
390 | { |
391 | struct sk_buff *head; |
392 | int len = 0; |
393 | unsigned long flags; |
394 | |
395 | spin_lock_irqsave(&sk->sk_receive_queue.lock, flags); |
396 | head = skb_peek(&sk->sk_receive_queue); |
397 | if (likely(head)) { |
398 | len = head->len; |
399 | if (vlan_tx_tag_present(head)) |
400 | len += VLAN_HLEN; |
401 | } |
402 | |
403 | spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags); |
404 | return len; |
405 | } |
406 | |
407 | /* This is a multi-buffer version of vhost_get_desc, that works if |
408 | * vq has read descriptors only. |
409 | * @vq - the relevant virtqueue |
410 | * @datalen - data length we'll be reading |
411 | * @iovcount - returned count of io vectors we fill |
412 | * @log - vhost log |
413 | * @log_num - log offset |
414 | * @quota - headcount quota, 1 for big buffer |
415 | * returns number of buffer heads allocated, negative on error |
416 | */ |
417 | static int get_rx_bufs(struct vhost_virtqueue *vq, |
418 | struct vring_used_elem *heads, |
419 | int datalen, |
420 | unsigned *iovcount, |
421 | struct vhost_log *log, |
422 | unsigned *log_num, |
423 | unsigned int quota) |
424 | { |
425 | unsigned int out, in; |
426 | int seg = 0; |
427 | int headcount = 0; |
428 | unsigned d; |
429 | int r, nlogs = 0; |
430 | |
431 | while (datalen > 0 && headcount < quota) { |
432 | if (unlikely(seg >= UIO_MAXIOV)) { |
433 | r = -ENOBUFS; |
434 | goto err; |
435 | } |
436 | d = vhost_get_vq_desc(vq->dev, vq, vq->iov + seg, |
437 | ARRAY_SIZE(vq->iov) - seg, &out, |
438 | &in, log, log_num); |
439 | if (d == vq->num) { |
440 | r = 0; |
441 | goto err; |
442 | } |
443 | if (unlikely(out || in <= 0)) { |
444 | vq_err(vq, "unexpected descriptor format for RX: " |
445 | "out %d, in %d\n", out, in); |
446 | r = -EINVAL; |
447 | goto err; |
448 | } |
449 | if (unlikely(log)) { |
450 | nlogs += *log_num; |
451 | log += *log_num; |
452 | } |
453 | heads[headcount].id = d; |
454 | heads[headcount].len = iov_length(vq->iov + seg, in); |
455 | datalen -= heads[headcount].len; |
456 | ++headcount; |
457 | seg += in; |
458 | } |
459 | heads[headcount - 1].len += datalen; |
460 | *iovcount = seg; |
461 | if (unlikely(log)) |
462 | *log_num = nlogs; |
463 | return headcount; |
464 | err: |
465 | vhost_discard_vq_desc(vq, headcount); |
466 | return r; |
467 | } |
468 | |
469 | /* Expects to be always run from workqueue - which acts as |
470 | * read-size critical section for our kind of RCU. */ |
471 | static void handle_rx(struct vhost_net *net) |
472 | { |
473 | struct vhost_virtqueue *vq = &net->dev.vqs[VHOST_NET_VQ_RX]; |
474 | unsigned uninitialized_var(in), log; |
475 | struct vhost_log *vq_log; |
476 | struct msghdr msg = { |
477 | .msg_name = NULL, |
478 | .msg_namelen = 0, |
479 | .msg_control = NULL, /* FIXME: get and handle RX aux data. */ |
480 | .msg_controllen = 0, |
481 | .msg_iov = vq->iov, |
482 | .msg_flags = MSG_DONTWAIT, |
483 | }; |
484 | struct virtio_net_hdr_mrg_rxbuf hdr = { |
485 | .hdr.flags = 0, |
486 | .hdr.gso_type = VIRTIO_NET_HDR_GSO_NONE |
487 | }; |
488 | size_t total_len = 0; |
489 | int err, mergeable; |
490 | s16 headcount; |
491 | size_t vhost_hlen, sock_hlen; |
492 | size_t vhost_len, sock_len; |
493 | /* TODO: check that we are running from vhost_worker? */ |
494 | struct socket *sock = rcu_dereference_check(vq->private_data, 1); |
495 | |
496 | if (!sock) |
497 | return; |
498 | |
499 | mutex_lock(&vq->mutex); |
500 | vhost_disable_notify(&net->dev, vq); |
501 | vhost_hlen = vq->vhost_hlen; |
502 | sock_hlen = vq->sock_hlen; |
503 | |
504 | vq_log = unlikely(vhost_has_feature(&net->dev, VHOST_F_LOG_ALL)) ? |
505 | vq->log : NULL; |
506 | mergeable = vhost_has_feature(&net->dev, VIRTIO_NET_F_MRG_RXBUF); |
507 | |
508 | while ((sock_len = peek_head_len(sock->sk))) { |
509 | sock_len += sock_hlen; |
510 | vhost_len = sock_len + vhost_hlen; |
511 | headcount = get_rx_bufs(vq, vq->heads, vhost_len, |
512 | &in, vq_log, &log, |
513 | likely(mergeable) ? UIO_MAXIOV : 1); |
514 | /* On error, stop handling until the next kick. */ |
515 | if (unlikely(headcount < 0)) |
516 | break; |
517 | /* OK, now we need to know about added descriptors. */ |
518 | if (!headcount) { |
519 | if (unlikely(vhost_enable_notify(&net->dev, vq))) { |
520 | /* They have slipped one in as we were |
521 | * doing that: check again. */ |
522 | vhost_disable_notify(&net->dev, vq); |
523 | continue; |
524 | } |
525 | /* Nothing new? Wait for eventfd to tell us |
526 | * they refilled. */ |
527 | break; |
528 | } |
529 | /* We don't need to be notified again. */ |
530 | if (unlikely((vhost_hlen))) |
531 | /* Skip header. TODO: support TSO. */ |
532 | move_iovec_hdr(vq->iov, vq->hdr, vhost_hlen, in); |
533 | else |
534 | /* Copy the header for use in VIRTIO_NET_F_MRG_RXBUF: |
535 | * needed because recvmsg can modify msg_iov. */ |
536 | copy_iovec_hdr(vq->iov, vq->hdr, sock_hlen, in); |
537 | msg.msg_iovlen = in; |
538 | err = sock->ops->recvmsg(NULL, sock, &msg, |
539 | sock_len, MSG_DONTWAIT | MSG_TRUNC); |
540 | /* Userspace might have consumed the packet meanwhile: |
541 | * it's not supposed to do this usually, but might be hard |
542 | * to prevent. Discard data we got (if any) and keep going. */ |
543 | if (unlikely(err != sock_len)) { |
544 | pr_debug("Discarded rx packet: " |
545 | " len %d, expected %zd\n", err, sock_len); |
546 | vhost_discard_vq_desc(vq, headcount); |
547 | continue; |
548 | } |
549 | if (unlikely(vhost_hlen) && |
550 | memcpy_toiovecend(vq->hdr, (unsigned char *)&hdr, 0, |
551 | vhost_hlen)) { |
552 | vq_err(vq, "Unable to write vnet_hdr at addr %p\n", |
553 | vq->iov->iov_base); |
554 | break; |
555 | } |
556 | /* TODO: Should check and handle checksum. */ |
557 | if (likely(mergeable) && |
558 | memcpy_toiovecend(vq->hdr, (unsigned char *)&headcount, |
559 | offsetof(typeof(hdr), num_buffers), |
560 | sizeof hdr.num_buffers)) { |
561 | vq_err(vq, "Failed num_buffers write"); |
562 | vhost_discard_vq_desc(vq, headcount); |
563 | break; |
564 | } |
565 | vhost_add_used_and_signal_n(&net->dev, vq, vq->heads, |
566 | headcount); |
567 | if (unlikely(vq_log)) |
568 | vhost_log_write(vq, vq_log, log, vhost_len); |
569 | total_len += vhost_len; |
570 | if (unlikely(total_len >= VHOST_NET_WEIGHT)) { |
571 | vhost_poll_queue(&vq->poll); |
572 | break; |
573 | } |
574 | } |
575 | |
576 | mutex_unlock(&vq->mutex); |
577 | } |
578 | |
579 | static void handle_tx_kick(struct vhost_work *work) |
580 | { |
581 | struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, |
582 | poll.work); |
583 | struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); |
584 | |
585 | handle_tx(net); |
586 | } |
587 | |
588 | static void handle_rx_kick(struct vhost_work *work) |
589 | { |
590 | struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, |
591 | poll.work); |
592 | struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); |
593 | |
594 | handle_rx(net); |
595 | } |
596 | |
597 | static void handle_tx_net(struct vhost_work *work) |
598 | { |
599 | struct vhost_net *net = container_of(work, struct vhost_net, |
600 | poll[VHOST_NET_VQ_TX].work); |
601 | handle_tx(net); |
602 | } |
603 | |
604 | static void handle_rx_net(struct vhost_work *work) |
605 | { |
606 | struct vhost_net *net = container_of(work, struct vhost_net, |
607 | poll[VHOST_NET_VQ_RX].work); |
608 | handle_rx(net); |
609 | } |
610 | |
611 | static int vhost_net_open(struct inode *inode, struct file *f) |
612 | { |
613 | struct vhost_net *n = kmalloc(sizeof *n, GFP_KERNEL); |
614 | struct vhost_dev *dev; |
615 | int r; |
616 | |
617 | if (!n) |
618 | return -ENOMEM; |
619 | |
620 | dev = &n->dev; |
621 | n->vqs[VHOST_NET_VQ_TX].handle_kick = handle_tx_kick; |
622 | n->vqs[VHOST_NET_VQ_RX].handle_kick = handle_rx_kick; |
623 | r = vhost_dev_init(dev, n->vqs, VHOST_NET_VQ_MAX); |
624 | if (r < 0) { |
625 | kfree(n); |
626 | return r; |
627 | } |
628 | |
629 | vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, POLLOUT, dev); |
630 | vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, POLLIN, dev); |
631 | n->tx_poll_state = VHOST_NET_POLL_DISABLED; |
632 | |
633 | f->private_data = n; |
634 | |
635 | return 0; |
636 | } |
637 | |
638 | static void vhost_net_disable_vq(struct vhost_net *n, |
639 | struct vhost_virtqueue *vq) |
640 | { |
641 | if (!vq->private_data) |
642 | return; |
643 | if (vq == n->vqs + VHOST_NET_VQ_TX) { |
644 | tx_poll_stop(n); |
645 | n->tx_poll_state = VHOST_NET_POLL_DISABLED; |
646 | } else |
647 | vhost_poll_stop(n->poll + VHOST_NET_VQ_RX); |
648 | } |
649 | |
650 | static int vhost_net_enable_vq(struct vhost_net *n, |
651 | struct vhost_virtqueue *vq) |
652 | { |
653 | struct socket *sock; |
654 | int ret; |
655 | |
656 | sock = rcu_dereference_protected(vq->private_data, |
657 | lockdep_is_held(&vq->mutex)); |
658 | if (!sock) |
659 | return 0; |
660 | if (vq == n->vqs + VHOST_NET_VQ_TX) { |
661 | n->tx_poll_state = VHOST_NET_POLL_STOPPED; |
662 | ret = tx_poll_start(n, sock); |
663 | } else |
664 | ret = vhost_poll_start(n->poll + VHOST_NET_VQ_RX, sock->file); |
665 | |
666 | return ret; |
667 | } |
668 | |
669 | static struct socket *vhost_net_stop_vq(struct vhost_net *n, |
670 | struct vhost_virtqueue *vq) |
671 | { |
672 | struct socket *sock; |
673 | |
674 | mutex_lock(&vq->mutex); |
675 | sock = rcu_dereference_protected(vq->private_data, |
676 | lockdep_is_held(&vq->mutex)); |
677 | vhost_net_disable_vq(n, vq); |
678 | rcu_assign_pointer(vq->private_data, NULL); |
679 | mutex_unlock(&vq->mutex); |
680 | return sock; |
681 | } |
682 | |
683 | static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock, |
684 | struct socket **rx_sock) |
685 | { |
686 | *tx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_TX); |
687 | *rx_sock = vhost_net_stop_vq(n, n->vqs + VHOST_NET_VQ_RX); |
688 | } |
689 | |
690 | static void vhost_net_flush_vq(struct vhost_net *n, int index) |
691 | { |
692 | vhost_poll_flush(n->poll + index); |
693 | vhost_poll_flush(&n->dev.vqs[index].poll); |
694 | } |
695 | |
696 | static void vhost_net_flush(struct vhost_net *n) |
697 | { |
698 | vhost_net_flush_vq(n, VHOST_NET_VQ_TX); |
699 | vhost_net_flush_vq(n, VHOST_NET_VQ_RX); |
700 | if (n->dev.vqs[VHOST_NET_VQ_TX].ubufs) { |
701 | mutex_lock(&n->dev.vqs[VHOST_NET_VQ_TX].mutex); |
702 | n->tx_flush = true; |
703 | mutex_unlock(&n->dev.vqs[VHOST_NET_VQ_TX].mutex); |
704 | /* Wait for all lower device DMAs done. */ |
705 | vhost_ubuf_put_and_wait(n->dev.vqs[VHOST_NET_VQ_TX].ubufs); |
706 | mutex_lock(&n->dev.vqs[VHOST_NET_VQ_TX].mutex); |
707 | n->tx_flush = false; |
708 | kref_init(&n->dev.vqs[VHOST_NET_VQ_TX].ubufs->kref); |
709 | mutex_unlock(&n->dev.vqs[VHOST_NET_VQ_TX].mutex); |
710 | } |
711 | } |
712 | |
713 | static int vhost_net_release(struct inode *inode, struct file *f) |
714 | { |
715 | struct vhost_net *n = f->private_data; |
716 | struct socket *tx_sock; |
717 | struct socket *rx_sock; |
718 | |
719 | vhost_net_stop(n, &tx_sock, &rx_sock); |
720 | vhost_net_flush(n); |
721 | vhost_dev_stop(&n->dev); |
722 | vhost_dev_cleanup(&n->dev, false); |
723 | if (tx_sock) |
724 | fput(tx_sock->file); |
725 | if (rx_sock) |
726 | fput(rx_sock->file); |
727 | /* We do an extra flush before freeing memory, |
728 | * since jobs can re-queue themselves. */ |
729 | vhost_net_flush(n); |
730 | kfree(n); |
731 | return 0; |
732 | } |
733 | |
734 | static struct socket *get_raw_socket(int fd) |
735 | { |
736 | struct { |
737 | struct sockaddr_ll sa; |
738 | char buf[MAX_ADDR_LEN]; |
739 | } uaddr; |
740 | int uaddr_len = sizeof uaddr, r; |
741 | struct socket *sock = sockfd_lookup(fd, &r); |
742 | |
743 | if (!sock) |
744 | return ERR_PTR(-ENOTSOCK); |
745 | |
746 | /* Parameter checking */ |
747 | if (sock->sk->sk_type != SOCK_RAW) { |
748 | r = -ESOCKTNOSUPPORT; |
749 | goto err; |
750 | } |
751 | |
752 | r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa, |
753 | &uaddr_len, 0); |
754 | if (r) |
755 | goto err; |
756 | |
757 | if (uaddr.sa.sll_family != AF_PACKET) { |
758 | r = -EPFNOSUPPORT; |
759 | goto err; |
760 | } |
761 | return sock; |
762 | err: |
763 | fput(sock->file); |
764 | return ERR_PTR(r); |
765 | } |
766 | |
767 | static struct socket *get_tap_socket(int fd) |
768 | { |
769 | struct file *file = fget(fd); |
770 | struct socket *sock; |
771 | |
772 | if (!file) |
773 | return ERR_PTR(-EBADF); |
774 | sock = tun_get_socket(file); |
775 | if (!IS_ERR(sock)) |
776 | return sock; |
777 | sock = macvtap_get_socket(file); |
778 | if (IS_ERR(sock)) |
779 | fput(file); |
780 | return sock; |
781 | } |
782 | |
783 | static struct socket *get_socket(int fd) |
784 | { |
785 | struct socket *sock; |
786 | |
787 | /* special case to disable backend */ |
788 | if (fd == -1) |
789 | return NULL; |
790 | sock = get_raw_socket(fd); |
791 | if (!IS_ERR(sock)) |
792 | return sock; |
793 | sock = get_tap_socket(fd); |
794 | if (!IS_ERR(sock)) |
795 | return sock; |
796 | return ERR_PTR(-ENOTSOCK); |
797 | } |
798 | |
799 | static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) |
800 | { |
801 | struct socket *sock, *oldsock; |
802 | struct vhost_virtqueue *vq; |
803 | struct vhost_ubuf_ref *ubufs, *oldubufs = NULL; |
804 | int r; |
805 | |
806 | mutex_lock(&n->dev.mutex); |
807 | r = vhost_dev_check_owner(&n->dev); |
808 | if (r) |
809 | goto err; |
810 | |
811 | if (index >= VHOST_NET_VQ_MAX) { |
812 | r = -ENOBUFS; |
813 | goto err; |
814 | } |
815 | vq = n->vqs + index; |
816 | mutex_lock(&vq->mutex); |
817 | |
818 | /* Verify that ring has been setup correctly. */ |
819 | if (!vhost_vq_access_ok(vq)) { |
820 | r = -EFAULT; |
821 | goto err_vq; |
822 | } |
823 | sock = get_socket(fd); |
824 | if (IS_ERR(sock)) { |
825 | r = PTR_ERR(sock); |
826 | goto err_vq; |
827 | } |
828 | |
829 | /* start polling new socket */ |
830 | oldsock = rcu_dereference_protected(vq->private_data, |
831 | lockdep_is_held(&vq->mutex)); |
832 | if (sock != oldsock) { |
833 | ubufs = vhost_ubuf_alloc(vq, sock && vhost_sock_zcopy(sock)); |
834 | if (IS_ERR(ubufs)) { |
835 | r = PTR_ERR(ubufs); |
836 | goto err_ubufs; |
837 | } |
838 | |
839 | vhost_net_disable_vq(n, vq); |
840 | rcu_assign_pointer(vq->private_data, sock); |
841 | r = vhost_init_used(vq); |
842 | if (r) |
843 | goto err_used; |
844 | r = vhost_net_enable_vq(n, vq); |
845 | if (r) |
846 | goto err_used; |
847 | |
848 | oldubufs = vq->ubufs; |
849 | vq->ubufs = ubufs; |
850 | |
851 | n->tx_packets = 0; |
852 | n->tx_zcopy_err = 0; |
853 | n->tx_flush = false; |
854 | } |
855 | |
856 | mutex_unlock(&vq->mutex); |
857 | |
858 | if (oldubufs) { |
859 | vhost_ubuf_put_and_wait(oldubufs); |
860 | mutex_lock(&vq->mutex); |
861 | vhost_zerocopy_signal_used(n, vq); |
862 | mutex_unlock(&vq->mutex); |
863 | } |
864 | |
865 | if (oldsock) { |
866 | vhost_net_flush_vq(n, index); |
867 | fput(oldsock->file); |
868 | } |
869 | |
870 | mutex_unlock(&n->dev.mutex); |
871 | return 0; |
872 | |
873 | err_used: |
874 | rcu_assign_pointer(vq->private_data, oldsock); |
875 | vhost_net_enable_vq(n, vq); |
876 | if (ubufs) |
877 | vhost_ubuf_put_and_wait(ubufs); |
878 | err_ubufs: |
879 | fput(sock->file); |
880 | err_vq: |
881 | mutex_unlock(&vq->mutex); |
882 | err: |
883 | mutex_unlock(&n->dev.mutex); |
884 | return r; |
885 | } |
886 | |
887 | static long vhost_net_reset_owner(struct vhost_net *n) |
888 | { |
889 | struct socket *tx_sock = NULL; |
890 | struct socket *rx_sock = NULL; |
891 | long err; |
892 | |
893 | mutex_lock(&n->dev.mutex); |
894 | err = vhost_dev_check_owner(&n->dev); |
895 | if (err) |
896 | goto done; |
897 | vhost_net_stop(n, &tx_sock, &rx_sock); |
898 | vhost_net_flush(n); |
899 | err = vhost_dev_reset_owner(&n->dev); |
900 | done: |
901 | mutex_unlock(&n->dev.mutex); |
902 | if (tx_sock) |
903 | fput(tx_sock->file); |
904 | if (rx_sock) |
905 | fput(rx_sock->file); |
906 | return err; |
907 | } |
908 | |
909 | static int vhost_net_set_features(struct vhost_net *n, u64 features) |
910 | { |
911 | size_t vhost_hlen, sock_hlen, hdr_len; |
912 | int i; |
913 | |
914 | hdr_len = (features & (1 << VIRTIO_NET_F_MRG_RXBUF)) ? |
915 | sizeof(struct virtio_net_hdr_mrg_rxbuf) : |
916 | sizeof(struct virtio_net_hdr); |
917 | if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) { |
918 | /* vhost provides vnet_hdr */ |
919 | vhost_hlen = hdr_len; |
920 | sock_hlen = 0; |
921 | } else { |
922 | /* socket provides vnet_hdr */ |
923 | vhost_hlen = 0; |
924 | sock_hlen = hdr_len; |
925 | } |
926 | mutex_lock(&n->dev.mutex); |
927 | if ((features & (1 << VHOST_F_LOG_ALL)) && |
928 | !vhost_log_access_ok(&n->dev)) { |
929 | mutex_unlock(&n->dev.mutex); |
930 | return -EFAULT; |
931 | } |
932 | n->dev.acked_features = features; |
933 | smp_wmb(); |
934 | for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { |
935 | mutex_lock(&n->vqs[i].mutex); |
936 | n->vqs[i].vhost_hlen = vhost_hlen; |
937 | n->vqs[i].sock_hlen = sock_hlen; |
938 | mutex_unlock(&n->vqs[i].mutex); |
939 | } |
940 | vhost_net_flush(n); |
941 | mutex_unlock(&n->dev.mutex); |
942 | return 0; |
943 | } |
944 | |
945 | static long vhost_net_ioctl(struct file *f, unsigned int ioctl, |
946 | unsigned long arg) |
947 | { |
948 | struct vhost_net *n = f->private_data; |
949 | void __user *argp = (void __user *)arg; |
950 | u64 __user *featurep = argp; |
951 | struct vhost_vring_file backend; |
952 | u64 features; |
953 | int r; |
954 | |
955 | switch (ioctl) { |
956 | case VHOST_NET_SET_BACKEND: |
957 | if (copy_from_user(&backend, argp, sizeof backend)) |
958 | return -EFAULT; |
959 | return vhost_net_set_backend(n, backend.index, backend.fd); |
960 | case VHOST_GET_FEATURES: |
961 | features = VHOST_NET_FEATURES; |
962 | if (copy_to_user(featurep, &features, sizeof features)) |
963 | return -EFAULT; |
964 | return 0; |
965 | case VHOST_SET_FEATURES: |
966 | if (copy_from_user(&features, featurep, sizeof features)) |
967 | return -EFAULT; |
968 | if (features & ~VHOST_NET_FEATURES) |
969 | return -EOPNOTSUPP; |
970 | return vhost_net_set_features(n, features); |
971 | case VHOST_RESET_OWNER: |
972 | return vhost_net_reset_owner(n); |
973 | default: |
974 | mutex_lock(&n->dev.mutex); |
975 | r = vhost_dev_ioctl(&n->dev, ioctl, argp); |
976 | if (r == -ENOIOCTLCMD) |
977 | r = vhost_vring_ioctl(&n->dev, ioctl, argp); |
978 | else |
979 | vhost_net_flush(n); |
980 | mutex_unlock(&n->dev.mutex); |
981 | return r; |
982 | } |
983 | } |
984 | |
985 | #ifdef CONFIG_COMPAT |
986 | static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl, |
987 | unsigned long arg) |
988 | { |
989 | return vhost_net_ioctl(f, ioctl, (unsigned long)compat_ptr(arg)); |
990 | } |
991 | #endif |
992 | |
993 | static const struct file_operations vhost_net_fops = { |
994 | .owner = THIS_MODULE, |
995 | .release = vhost_net_release, |
996 | .unlocked_ioctl = vhost_net_ioctl, |
997 | #ifdef CONFIG_COMPAT |
998 | .compat_ioctl = vhost_net_compat_ioctl, |
999 | #endif |
1000 | .open = vhost_net_open, |
1001 | .llseek = noop_llseek, |
1002 | }; |
1003 | |
1004 | static struct miscdevice vhost_net_misc = { |
1005 | .minor = VHOST_NET_MINOR, |
1006 | .name = "vhost-net", |
1007 | .fops = &vhost_net_fops, |
1008 | }; |
1009 | |
1010 | static int vhost_net_init(void) |
1011 | { |
1012 | if (experimental_zcopytx) |
1013 | vhost_enable_zcopy(VHOST_NET_VQ_TX); |
1014 | return misc_register(&vhost_net_misc); |
1015 | } |
1016 | module_init(vhost_net_init); |
1017 | |
1018 | static void vhost_net_exit(void) |
1019 | { |
1020 | misc_deregister(&vhost_net_misc); |
1021 | } |
1022 | module_exit(vhost_net_exit); |
1023 | |
1024 | MODULE_VERSION("0.0.1"); |
1025 | MODULE_LICENSE("GPL v2"); |
1026 | MODULE_AUTHOR("Michael S. Tsirkin"); |
1027 | MODULE_DESCRIPTION("Host kernel accelerator for virtio net"); |
1028 | MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR); |
1029 | MODULE_ALIAS("devname:vhost-net"); |
1030 |
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Tags:
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v2.6.34-rc5
v2.6.34-rc6
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