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Revert "tty: hvc: Fix data abort due to race in hvc_open"
[linux/fpc-iii.git] / drivers / vhost / net.c
blob2927f02cc7e1b5af56c1626973f1499c96b25244
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
38 static int experimental_zcopytx = 0;
39 module_param(experimental_zcopytx, int, 0444);
40 MODULE_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
72 enum {
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
79 enum {
80 VHOST_NET_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2)
81 };
82
83 enum {
84 VHOST_NET_VQ_RX = 0,
85 VHOST_NET_VQ_TX = 1,
86 VHOST_NET_VQ_MAX = 2,
87 };
88
89 struct 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
101 struct vhost_net_buf {
102 void **queue;
103 int tail;
104 int head;
105 };
106
107 struct 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
131 struct 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
149 static unsigned vhost_net_zcopy_mask __read_mostly;
150
151 static 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
159 static int vhost_net_buf_get_size(struct vhost_net_buf *rxq)
160 {
161 return rxq->tail - rxq->head;
162 }
163
164 static int vhost_net_buf_is_empty(struct vhost_net_buf *rxq)
165 {
166 return rxq->tail == rxq->head;
167 }
168
169 static 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
176 static 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
186 static 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
198 static 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
209 static 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
219 out:
220 return vhost_net_buf_peek_len(vhost_net_buf_get_ptr(rxq));
221 }
222
223 static void vhost_net_buf_init(struct vhost_net_buf *rxq)
224 {
225 rxq->head = rxq->tail = 0;
226 }
227
228 static void vhost_net_enable_zcopy(int vq)
229 {
230 vhost_net_zcopy_mask |= 0x1 << vq;
231 }
232
233 static struct vhost_net_ubuf_ref *
234 vhost_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
249 static 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
257 static 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
263 static 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
269 static 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
279 static 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
297 err:
298 vhost_net_clear_ubuf_info(n);
299 return -ENOMEM;
300 }
301
302 static 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
319 static 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
328 static void vhost_net_tx_err(struct vhost_net *net)
329 {
330 ++net->tx_zcopy_err;
331 }
332
333 static 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
342 static bool vhost_sock_zcopy(struct socket *sock)
343 {
344 return unlikely(experimental_zcopytx) &&
345 sock_flag(sock->sk, SOCK_ZEROCOPY);
346 }
347
348 static 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 */
358 static 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
384 static 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
410 static inline unsigned long busy_clock(void)
411 {
412 return local_clock() >> 10;
413 }
414
415 static 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
421 static 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 (!vhost_vq_get_backend(vq))
428 return;
429 vhost_poll_stop(poll);
430 }
431
432 static 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 = vhost_vq_get_backend(vq);
441 if (!sock)
442 return 0;
443
444 return vhost_poll_start(poll, sock->file);
445 }
446
447 static 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
459 static 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
481 signal_used:
482 vhost_net_signal_used(nvq);
483 nvq->batched_xdp = 0;
484 }
485
486 static 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
497 static 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
508 static 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 = vhost_vq_get_backend(rvq);
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
559 static 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(vhost_vq_get_backend(tvq)))
574 vhost_tx_batch(net, tnvq,
575 vhost_vq_get_backend(tvq),
576 msghdr);
577
578 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, false);
579
580 r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov),
581 out_num, in_num, NULL, NULL);
582 }
583
584 return r;
585 }
586
587 static bool vhost_exceeds_maxpend(struct vhost_net *net)
588 {
589 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
590 struct vhost_virtqueue *vq = &nvq->vq;
591
592 return (nvq->upend_idx + UIO_MAXIOV - nvq->done_idx) % UIO_MAXIOV >
593 min_t(unsigned int, VHOST_MAX_PEND, vq->num >> 2);
594 }
595
596 static size_t init_iov_iter(struct vhost_virtqueue *vq, struct iov_iter *iter,
597 size_t hdr_size, int out)
598 {
599 /* Skip header. TODO: support TSO. */
600 size_t len = iov_length(vq->iov, out);
601
602 iov_iter_init(iter, WRITE, vq->iov, out, len);
603 iov_iter_advance(iter, hdr_size);
604
605 return iov_iter_count(iter);
606 }
607
608 static int get_tx_bufs(struct vhost_net *net,
609 struct vhost_net_virtqueue *nvq,
610 struct msghdr *msg,
611 unsigned int *out, unsigned int *in,
612 size_t *len, bool *busyloop_intr)
613 {
614 struct vhost_virtqueue *vq = &nvq->vq;
615 int ret;
616
617 ret = vhost_net_tx_get_vq_desc(net, nvq, out, in, msg, busyloop_intr);
618
619 if (ret < 0 || ret == vq->num)
620 return ret;
621
622 if (*in) {
623 vq_err(vq, "Unexpected descriptor format for TX: out %d, int %d\n",
624 *out, *in);
625 return -EFAULT;
626 }
627
628 /* Sanity check */
629 *len = init_iov_iter(vq, &msg->msg_iter, nvq->vhost_hlen, *out);
630 if (*len == 0) {
631 vq_err(vq, "Unexpected header len for TX: %zd expected %zd\n",
632 *len, nvq->vhost_hlen);
633 return -EFAULT;
634 }
635
636 return ret;
637 }
638
639 static bool tx_can_batch(struct vhost_virtqueue *vq, size_t total_len)
640 {
641 return total_len < VHOST_NET_WEIGHT &&
642 !vhost_vq_avail_empty(vq->dev, vq);
643 }
644
645 #define SKB_FRAG_PAGE_ORDER get_order(32768)
646
647 static bool vhost_net_page_frag_refill(struct vhost_net *net, unsigned int sz,
648 struct page_frag *pfrag, gfp_t gfp)
649 {
650 if (pfrag->page) {
651 if (pfrag->offset + sz <= pfrag->size)
652 return true;
653 __page_frag_cache_drain(pfrag->page, net->refcnt_bias);
654 }
655
656 pfrag->offset = 0;
657 net->refcnt_bias = 0;
658 if (SKB_FRAG_PAGE_ORDER) {
659 /* Avoid direct reclaim but allow kswapd to wake */
660 pfrag->page = alloc_pages((gfp & ~__GFP_DIRECT_RECLAIM) |
661 __GFP_COMP | __GFP_NOWARN |
662 __GFP_NORETRY,
663 SKB_FRAG_PAGE_ORDER);
664 if (likely(pfrag->page)) {
665 pfrag->size = PAGE_SIZE << SKB_FRAG_PAGE_ORDER;
666 goto done;
667 }
668 }
669 pfrag->page = alloc_page(gfp);
670 if (likely(pfrag->page)) {
671 pfrag->size = PAGE_SIZE;
672 goto done;
673 }
674 return false;
675
676 done:
677 net->refcnt_bias = USHRT_MAX;
678 page_ref_add(pfrag->page, USHRT_MAX - 1);
679 return true;
680 }
681
682 #define VHOST_NET_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
683
684 static int vhost_net_build_xdp(struct vhost_net_virtqueue *nvq,
685 struct iov_iter *from)
686 {
687 struct vhost_virtqueue *vq = &nvq->vq;
688 struct vhost_net *net = container_of(vq->dev, struct vhost_net,
689 dev);
690 struct socket *sock = vhost_vq_get_backend(vq);
691 struct page_frag *alloc_frag = &net->page_frag;
692 struct virtio_net_hdr *gso;
693 struct xdp_buff *xdp = &nvq->xdp[nvq->batched_xdp];
694 struct tun_xdp_hdr *hdr;
695 size_t len = iov_iter_count(from);
696 int headroom = vhost_sock_xdp(sock) ? XDP_PACKET_HEADROOM : 0;
697 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
698 int pad = SKB_DATA_ALIGN(VHOST_NET_RX_PAD + headroom + nvq->sock_hlen);
699 int sock_hlen = nvq->sock_hlen;
700 void *buf;
701 int copied;
702
703 if (unlikely(len < nvq->sock_hlen))
704 return -EFAULT;
705
706 if (SKB_DATA_ALIGN(len + pad) +
707 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
708 return -ENOSPC;
709
710 buflen += SKB_DATA_ALIGN(len + pad);
711 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
712 if (unlikely(!vhost_net_page_frag_refill(net, buflen,
713 alloc_frag, GFP_KERNEL)))
714 return -ENOMEM;
715
716 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
717 copied = copy_page_from_iter(alloc_frag->page,
718 alloc_frag->offset +
719 offsetof(struct tun_xdp_hdr, gso),
720 sock_hlen, from);
721 if (copied != sock_hlen)
722 return -EFAULT;
723
724 hdr = buf;
725 gso = &hdr->gso;
726
727 if ((gso->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
728 vhost16_to_cpu(vq, gso->csum_start) +
729 vhost16_to_cpu(vq, gso->csum_offset) + 2 >
730 vhost16_to_cpu(vq, gso->hdr_len)) {
731 gso->hdr_len = cpu_to_vhost16(vq,
732 vhost16_to_cpu(vq, gso->csum_start) +
733 vhost16_to_cpu(vq, gso->csum_offset) + 2);
734
735 if (vhost16_to_cpu(vq, gso->hdr_len) > len)
736 return -EINVAL;
737 }
738
739 len -= sock_hlen;
740 copied = copy_page_from_iter(alloc_frag->page,
741 alloc_frag->offset + pad,
742 len, from);
743 if (copied != len)
744 return -EFAULT;
745
746 xdp->data_hard_start = buf;
747 xdp->data = buf + pad;
748 xdp->data_end = xdp->data + len;
749 hdr->buflen = buflen;
750
751 --net->refcnt_bias;
752 alloc_frag->offset += buflen;
753
754 ++nvq->batched_xdp;
755
756 return 0;
757 }
758
759 static void handle_tx_copy(struct vhost_net *net, struct socket *sock)
760 {
761 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
762 struct vhost_virtqueue *vq = &nvq->vq;
763 unsigned out, in;
764 int head;
765 struct msghdr msg = {
766 .msg_name = NULL,
767 .msg_namelen = 0,
768 .msg_control = NULL,
769 .msg_controllen = 0,
770 .msg_flags = MSG_DONTWAIT,
771 };
772 size_t len, total_len = 0;
773 int err;
774 int sent_pkts = 0;
775 bool sock_can_batch = (sock->sk->sk_sndbuf == INT_MAX);
776
777 do {
778 bool busyloop_intr = false;
779
780 if (nvq->done_idx == VHOST_NET_BATCH)
781 vhost_tx_batch(net, nvq, sock, &msg);
782
783 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len,
784 &busyloop_intr);
785 /* On error, stop handling until the next kick. */
786 if (unlikely(head < 0))
787 break;
788 /* Nothing new? Wait for eventfd to tell us they refilled. */
789 if (head == vq->num) {
790 if (unlikely(busyloop_intr)) {
791 vhost_poll_queue(&vq->poll);
792 } else if (unlikely(vhost_enable_notify(&net->dev,
793 vq))) {
794 vhost_disable_notify(&net->dev, vq);
795 continue;
796 }
797 break;
798 }
799
800 total_len += len;
801
802 /* For simplicity, TX batching is only enabled if
803 * sndbuf is unlimited.
804 */
805 if (sock_can_batch) {
806 err = vhost_net_build_xdp(nvq, &msg.msg_iter);
807 if (!err) {
808 goto done;
809 } else if (unlikely(err != -ENOSPC)) {
810 vhost_tx_batch(net, nvq, sock, &msg);
811 vhost_discard_vq_desc(vq, 1);
812 vhost_net_enable_vq(net, vq);
813 break;
814 }
815
816 /* We can't build XDP buff, go for single
817 * packet path but let's flush batched
818 * packets.
819 */
820 vhost_tx_batch(net, nvq, sock, &msg);
821 msg.msg_control = NULL;
822 } else {
823 if (tx_can_batch(vq, total_len))
824 msg.msg_flags |= MSG_MORE;
825 else
826 msg.msg_flags &= ~MSG_MORE;
827 }
828
829 /* TODO: Check specific error and bomb out unless ENOBUFS? */
830 err = sock->ops->sendmsg(sock, &msg, len);
831 if (unlikely(err < 0)) {
832 vhost_discard_vq_desc(vq, 1);
833 vhost_net_enable_vq(net, vq);
834 break;
835 }
836 if (err != len)
837 pr_debug("Truncated TX packet: len %d != %zd\n",
838 err, len);
839 done:
840 vq->heads[nvq->done_idx].id = cpu_to_vhost32(vq, head);
841 vq->heads[nvq->done_idx].len = 0;
842 ++nvq->done_idx;
843 } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len)));
844
845 vhost_tx_batch(net, nvq, sock, &msg);
846 }
847
848 static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock)
849 {
850 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
851 struct vhost_virtqueue *vq = &nvq->vq;
852 unsigned out, in;
853 int head;
854 struct msghdr msg = {
855 .msg_name = NULL,
856 .msg_namelen = 0,
857 .msg_control = NULL,
858 .msg_controllen = 0,
859 .msg_flags = MSG_DONTWAIT,
860 };
861 struct tun_msg_ctl ctl;
862 size_t len, total_len = 0;
863 int err;
864 struct vhost_net_ubuf_ref *uninitialized_var(ubufs);
865 bool zcopy_used;
866 int sent_pkts = 0;
867
868 do {
869 bool busyloop_intr;
870
871 /* Release DMAs done buffers first */
872 vhost_zerocopy_signal_used(net, vq);
873
874 busyloop_intr = false;
875 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len,
876 &busyloop_intr);
877 /* On error, stop handling until the next kick. */
878 if (unlikely(head < 0))
879 break;
880 /* Nothing new? Wait for eventfd to tell us they refilled. */
881 if (head == vq->num) {
882 if (unlikely(busyloop_intr)) {
883 vhost_poll_queue(&vq->poll);
884 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) {
885 vhost_disable_notify(&net->dev, vq);
886 continue;
887 }
888 break;
889 }
890
891 zcopy_used = len >= VHOST_GOODCOPY_LEN
892 && !vhost_exceeds_maxpend(net)
893 && vhost_net_tx_select_zcopy(net);
894
895 /* use msg_control to pass vhost zerocopy ubuf info to skb */
896 if (zcopy_used) {
897 struct ubuf_info *ubuf;
898 ubuf = nvq->ubuf_info + nvq->upend_idx;
899
900 vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head);
901 vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS;
902 ubuf->callback = vhost_zerocopy_callback;
903 ubuf->ctx = nvq->ubufs;
904 ubuf->desc = nvq->upend_idx;
905 refcount_set(&ubuf->refcnt, 1);
906 msg.msg_control = &ctl;
907 ctl.type = TUN_MSG_UBUF;
908 ctl.ptr = ubuf;
909 msg.msg_controllen = sizeof(ctl);
910 ubufs = nvq->ubufs;
911 atomic_inc(&ubufs->refcount);
912 nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV;
913 } else {
914 msg.msg_control = NULL;
915 ubufs = NULL;
916 }
917 total_len += len;
918 if (tx_can_batch(vq, total_len) &&
919 likely(!vhost_exceeds_maxpend(net))) {
920 msg.msg_flags |= MSG_MORE;
921 } else {
922 msg.msg_flags &= ~MSG_MORE;
923 }
924
925 /* TODO: Check specific error and bomb out unless ENOBUFS? */
926 err = sock->ops->sendmsg(sock, &msg, len);
927 if (unlikely(err < 0)) {
928 if (zcopy_used) {
929 vhost_net_ubuf_put(ubufs);
930 nvq->upend_idx = ((unsigned)nvq->upend_idx - 1)
931 % UIO_MAXIOV;
932 }
933 vhost_discard_vq_desc(vq, 1);
934 vhost_net_enable_vq(net, vq);
935 break;
936 }
937 if (err != len)
938 pr_debug("Truncated TX packet: "
939 " len %d != %zd\n", err, len);
940 if (!zcopy_used)
941 vhost_add_used_and_signal(&net->dev, vq, head, 0);
942 else
943 vhost_zerocopy_signal_used(net, vq);
944 vhost_net_tx_packet(net);
945 } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len)));
946 }
947
948 /* Expects to be always run from workqueue - which acts as
949 * read-size critical section for our kind of RCU. */
950 static void handle_tx(struct vhost_net *net)
951 {
952 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
953 struct vhost_virtqueue *vq = &nvq->vq;
954 struct socket *sock;
955
956 mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_TX);
957 sock = vhost_vq_get_backend(vq);
958 if (!sock)
959 goto out;
960
961 if (!vq_meta_prefetch(vq))
962 goto out;
963
964 vhost_disable_notify(&net->dev, vq);
965 vhost_net_disable_vq(net, vq);
966
967 if (vhost_sock_zcopy(sock))
968 handle_tx_zerocopy(net, sock);
969 else
970 handle_tx_copy(net, sock);
971
972 out:
973 mutex_unlock(&vq->mutex);
974 }
975
976 static int peek_head_len(struct vhost_net_virtqueue *rvq, struct sock *sk)
977 {
978 struct sk_buff *head;
979 int len = 0;
980 unsigned long flags;
981
982 if (rvq->rx_ring)
983 return vhost_net_buf_peek(rvq);
984
985 spin_lock_irqsave(&sk->sk_receive_queue.lock, flags);
986 head = skb_peek(&sk->sk_receive_queue);
987 if (likely(head)) {
988 len = head->len;
989 if (skb_vlan_tag_present(head))
990 len += VLAN_HLEN;
991 }
992
993 spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags);
994 return len;
995 }
996
997 static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk,
998 bool *busyloop_intr)
999 {
1000 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX];
1001 struct vhost_net_virtqueue *tnvq = &net->vqs[VHOST_NET_VQ_TX];
1002 struct vhost_virtqueue *rvq = &rnvq->vq;
1003 struct vhost_virtqueue *tvq = &tnvq->vq;
1004 int len = peek_head_len(rnvq, sk);
1005
1006 if (!len && rvq->busyloop_timeout) {
1007 /* Flush batched heads first */
1008 vhost_net_signal_used(rnvq);
1009 /* Both tx vq and rx socket were polled here */
1010 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, true);
1011
1012 len = peek_head_len(rnvq, sk);
1013 }
1014
1015 return len;
1016 }
1017
1018 /* This is a multi-buffer version of vhost_get_desc, that works if
1019 * vq has read descriptors only.
1020 * @vq - the relevant virtqueue
1021 * @datalen - data length we'll be reading
1022 * @iovcount - returned count of io vectors we fill
1023 * @log - vhost log
1024 * @log_num - log offset
1025 * @quota - headcount quota, 1 for big buffer
1026 * returns number of buffer heads allocated, negative on error
1027 */
1028 static int get_rx_bufs(struct vhost_virtqueue *vq,
1029 struct vring_used_elem *heads,
1030 int datalen,
1031 unsigned *iovcount,
1032 struct vhost_log *log,
1033 unsigned *log_num,
1034 unsigned int quota)
1035 {
1036 unsigned int out, in;
1037 int seg = 0;
1038 int headcount = 0;
1039 unsigned d;
1040 int r, nlogs = 0;
1041 /* len is always initialized before use since we are always called with
1042 * datalen > 0.
1043 */
1044 u32 uninitialized_var(len);
1045
1046 while (datalen > 0 && headcount < quota) {
1047 if (unlikely(seg >= UIO_MAXIOV)) {
1048 r = -ENOBUFS;
1049 goto err;
1050 }
1051 r = vhost_get_vq_desc(vq, vq->iov + seg,
1052 ARRAY_SIZE(vq->iov) - seg, &out,
1053 &in, log, log_num);
1054 if (unlikely(r < 0))
1055 goto err;
1056
1057 d = r;
1058 if (d == vq->num) {
1059 r = 0;
1060 goto err;
1061 }
1062 if (unlikely(out || in <= 0)) {
1063 vq_err(vq, "unexpected descriptor format for RX: "
1064 "out %d, in %d\n", out, in);
1065 r = -EINVAL;
1066 goto err;
1067 }
1068 if (unlikely(log)) {
1069 nlogs += *log_num;
1070 log += *log_num;
1071 }
1072 heads[headcount].id = cpu_to_vhost32(vq, d);
1073 len = iov_length(vq->iov + seg, in);
1074 heads[headcount].len = cpu_to_vhost32(vq, len);
1075 datalen -= len;
1076 ++headcount;
1077 seg += in;
1078 }
1079 heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen);
1080 *iovcount = seg;
1081 if (unlikely(log))
1082 *log_num = nlogs;
1083
1084 /* Detect overrun */
1085 if (unlikely(datalen > 0)) {
1086 r = UIO_MAXIOV + 1;
1087 goto err;
1088 }
1089 return headcount;
1090 err:
1091 vhost_discard_vq_desc(vq, headcount);
1092 return r;
1093 }
1094
1095 /* Expects to be always run from workqueue - which acts as
1096 * read-size critical section for our kind of RCU. */
1097 static void handle_rx(struct vhost_net *net)
1098 {
1099 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX];
1100 struct vhost_virtqueue *vq = &nvq->vq;
1101 unsigned uninitialized_var(in), log;
1102 struct vhost_log *vq_log;
1103 struct msghdr msg = {
1104 .msg_name = NULL,
1105 .msg_namelen = 0,
1106 .msg_control = NULL, /* FIXME: get and handle RX aux data. */
1107 .msg_controllen = 0,
1108 .msg_flags = MSG_DONTWAIT,
1109 };
1110 struct virtio_net_hdr hdr = {
1111 .flags = 0,
1112 .gso_type = VIRTIO_NET_HDR_GSO_NONE
1113 };
1114 size_t total_len = 0;
1115 int err, mergeable;
1116 s16 headcount;
1117 size_t vhost_hlen, sock_hlen;
1118 size_t vhost_len, sock_len;
1119 bool busyloop_intr = false;
1120 struct socket *sock;
1121 struct iov_iter fixup;
1122 __virtio16 num_buffers;
1123 int recv_pkts = 0;
1124
1125 mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_RX);
1126 sock = vhost_vq_get_backend(vq);
1127 if (!sock)
1128 goto out;
1129
1130 if (!vq_meta_prefetch(vq))
1131 goto out;
1132
1133 vhost_disable_notify(&net->dev, vq);
1134 vhost_net_disable_vq(net, vq);
1135
1136 vhost_hlen = nvq->vhost_hlen;
1137 sock_hlen = nvq->sock_hlen;
1138
1139 vq_log = unlikely(vhost_has_feature(vq, VHOST_F_LOG_ALL)) ?
1140 vq->log : NULL;
1141 mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF);
1142
1143 do {
1144 sock_len = vhost_net_rx_peek_head_len(net, sock->sk,
1145 &busyloop_intr);
1146 if (!sock_len)
1147 break;
1148 sock_len += sock_hlen;
1149 vhost_len = sock_len + vhost_hlen;
1150 headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx,
1151 vhost_len, &in, vq_log, &log,
1152 likely(mergeable) ? UIO_MAXIOV : 1);
1153 /* On error, stop handling until the next kick. */
1154 if (unlikely(headcount < 0))
1155 goto out;
1156 /* OK, now we need to know about added descriptors. */
1157 if (!headcount) {
1158 if (unlikely(busyloop_intr)) {
1159 vhost_poll_queue(&vq->poll);
1160 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) {
1161 /* They have slipped one in as we were
1162 * doing that: check again. */
1163 vhost_disable_notify(&net->dev, vq);
1164 continue;
1165 }
1166 /* Nothing new? Wait for eventfd to tell us
1167 * they refilled. */
1168 goto out;
1169 }
1170 busyloop_intr = false;
1171 if (nvq->rx_ring)
1172 msg.msg_control = vhost_net_buf_consume(&nvq->rxq);
1173 /* On overrun, truncate and discard */
1174 if (unlikely(headcount > UIO_MAXIOV)) {
1175 iov_iter_init(&msg.msg_iter, READ, vq->iov, 1, 1);
1176 err = sock->ops->recvmsg(sock, &msg,
1177 1, MSG_DONTWAIT | MSG_TRUNC);
1178 pr_debug("Discarded rx packet: len %zd\n", sock_len);
1179 continue;
1180 }
1181 /* We don't need to be notified again. */
1182 iov_iter_init(&msg.msg_iter, READ, vq->iov, in, vhost_len);
1183 fixup = msg.msg_iter;
1184 if (unlikely((vhost_hlen))) {
1185 /* We will supply the header ourselves
1186 * TODO: support TSO.
1187 */
1188 iov_iter_advance(&msg.msg_iter, vhost_hlen);
1189 }
1190 err = sock->ops->recvmsg(sock, &msg,
1191 sock_len, MSG_DONTWAIT | MSG_TRUNC);
1192 /* Userspace might have consumed the packet meanwhile:
1193 * it's not supposed to do this usually, but might be hard
1194 * to prevent. Discard data we got (if any) and keep going. */
1195 if (unlikely(err != sock_len)) {
1196 pr_debug("Discarded rx packet: "
1197 " len %d, expected %zd\n", err, sock_len);
1198 vhost_discard_vq_desc(vq, headcount);
1199 continue;
1200 }
1201 /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */
1202 if (unlikely(vhost_hlen)) {
1203 if (copy_to_iter(&hdr, sizeof(hdr),
1204 &fixup) != sizeof(hdr)) {
1205 vq_err(vq, "Unable to write vnet_hdr "
1206 "at addr %p\n", vq->iov->iov_base);
1207 goto out;
1208 }
1209 } else {
1210 /* Header came from socket; we'll need to patch
1211 * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF
1212 */
1213 iov_iter_advance(&fixup, sizeof(hdr));
1214 }
1215 /* TODO: Should check and handle checksum. */
1216
1217 num_buffers = cpu_to_vhost16(vq, headcount);
1218 if (likely(mergeable) &&
1219 copy_to_iter(&num_buffers, sizeof num_buffers,
1220 &fixup) != sizeof num_buffers) {
1221 vq_err(vq, "Failed num_buffers write");
1222 vhost_discard_vq_desc(vq, headcount);
1223 goto out;
1224 }
1225 nvq->done_idx += headcount;
1226 if (nvq->done_idx > VHOST_NET_BATCH)
1227 vhost_net_signal_used(nvq);
1228 if (unlikely(vq_log))
1229 vhost_log_write(vq, vq_log, log, vhost_len,
1230 vq->iov, in);
1231 total_len += vhost_len;
1232 } while (likely(!vhost_exceeds_weight(vq, ++recv_pkts, total_len)));
1233
1234 if (unlikely(busyloop_intr))
1235 vhost_poll_queue(&vq->poll);
1236 else if (!sock_len)
1237 vhost_net_enable_vq(net, vq);
1238 out:
1239 vhost_net_signal_used(nvq);
1240 mutex_unlock(&vq->mutex);
1241 }
1242
1243 static void handle_tx_kick(struct vhost_work *work)
1244 {
1245 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
1246 poll.work);
1247 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
1248
1249 handle_tx(net);
1250 }
1251
1252 static void handle_rx_kick(struct vhost_work *work)
1253 {
1254 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
1255 poll.work);
1256 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
1257
1258 handle_rx(net);
1259 }
1260
1261 static void handle_tx_net(struct vhost_work *work)
1262 {
1263 struct vhost_net *net = container_of(work, struct vhost_net,
1264 poll[VHOST_NET_VQ_TX].work);
1265 handle_tx(net);
1266 }
1267
1268 static void handle_rx_net(struct vhost_work *work)
1269 {
1270 struct vhost_net *net = container_of(work, struct vhost_net,
1271 poll[VHOST_NET_VQ_RX].work);
1272 handle_rx(net);
1273 }
1274
1275 static int vhost_net_open(struct inode *inode, struct file *f)
1276 {
1277 struct vhost_net *n;
1278 struct vhost_dev *dev;
1279 struct vhost_virtqueue **vqs;
1280 void **queue;
1281 struct xdp_buff *xdp;
1282 int i;
1283
1284 n = kvmalloc(sizeof *n, GFP_KERNEL | __GFP_RETRY_MAYFAIL);
1285 if (!n)
1286 return -ENOMEM;
1287 vqs = kmalloc_array(VHOST_NET_VQ_MAX, sizeof(*vqs), GFP_KERNEL);
1288 if (!vqs) {
1289 kvfree(n);
1290 return -ENOMEM;
1291 }
1292
1293 queue = kmalloc_array(VHOST_NET_BATCH, sizeof(void *),
1294 GFP_KERNEL);
1295 if (!queue) {
1296 kfree(vqs);
1297 kvfree(n);
1298 return -ENOMEM;
1299 }
1300 n->vqs[VHOST_NET_VQ_RX].rxq.queue = queue;
1301
1302 xdp = kmalloc_array(VHOST_NET_BATCH, sizeof(*xdp), GFP_KERNEL);
1303 if (!xdp) {
1304 kfree(vqs);
1305 kvfree(n);
1306 kfree(queue);
1307 return -ENOMEM;
1308 }
1309 n->vqs[VHOST_NET_VQ_TX].xdp = xdp;
1310
1311 dev = &n->dev;
1312 vqs[VHOST_NET_VQ_TX] = &n->vqs[VHOST_NET_VQ_TX].vq;
1313 vqs[VHOST_NET_VQ_RX] = &n->vqs[VHOST_NET_VQ_RX].vq;
1314 n->vqs[VHOST_NET_VQ_TX].vq.handle_kick = handle_tx_kick;
1315 n->vqs[VHOST_NET_VQ_RX].vq.handle_kick = handle_rx_kick;
1316 for (i = 0; i < VHOST_NET_VQ_MAX; i++) {
1317 n->vqs[i].ubufs = NULL;
1318 n->vqs[i].ubuf_info = NULL;
1319 n->vqs[i].upend_idx = 0;
1320 n->vqs[i].done_idx = 0;
1321 n->vqs[i].batched_xdp = 0;
1322 n->vqs[i].vhost_hlen = 0;
1323 n->vqs[i].sock_hlen = 0;
1324 n->vqs[i].rx_ring = NULL;
1325 vhost_net_buf_init(&n->vqs[i].rxq);
1326 }
1327 vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX,
1328 UIO_MAXIOV + VHOST_NET_BATCH,
1329 VHOST_NET_PKT_WEIGHT, VHOST_NET_WEIGHT,
1330 NULL);
1331
1332 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, EPOLLOUT, dev);
1333 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, EPOLLIN, dev);
1334
1335 f->private_data = n;
1336 n->page_frag.page = NULL;
1337 n->refcnt_bias = 0;
1338
1339 return 0;
1340 }
1341
1342 static struct socket *vhost_net_stop_vq(struct vhost_net *n,
1343 struct vhost_virtqueue *vq)
1344 {
1345 struct socket *sock;
1346 struct vhost_net_virtqueue *nvq =
1347 container_of(vq, struct vhost_net_virtqueue, vq);
1348
1349 mutex_lock(&vq->mutex);
1350 sock = vhost_vq_get_backend(vq);
1351 vhost_net_disable_vq(n, vq);
1352 vhost_vq_set_backend(vq, NULL);
1353 vhost_net_buf_unproduce(nvq);
1354 nvq->rx_ring = NULL;
1355 mutex_unlock(&vq->mutex);
1356 return sock;
1357 }
1358
1359 static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock,
1360 struct socket **rx_sock)
1361 {
1362 *tx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_TX].vq);
1363 *rx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_RX].vq);
1364 }
1365
1366 static void vhost_net_flush_vq(struct vhost_net *n, int index)
1367 {
1368 vhost_poll_flush(n->poll + index);
1369 vhost_poll_flush(&n->vqs[index].vq.poll);
1370 }
1371
1372 static void vhost_net_flush(struct vhost_net *n)
1373 {
1374 vhost_net_flush_vq(n, VHOST_NET_VQ_TX);
1375 vhost_net_flush_vq(n, VHOST_NET_VQ_RX);
1376 if (n->vqs[VHOST_NET_VQ_TX].ubufs) {
1377 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1378 n->tx_flush = true;
1379 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1380 /* Wait for all lower device DMAs done. */
1381 vhost_net_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs);
1382 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1383 n->tx_flush = false;
1384 atomic_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1);
1385 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1386 }
1387 }
1388
1389 static int vhost_net_release(struct inode *inode, struct file *f)
1390 {
1391 struct vhost_net *n = f->private_data;
1392 struct socket *tx_sock;
1393 struct socket *rx_sock;
1394
1395 vhost_net_stop(n, &tx_sock, &rx_sock);
1396 vhost_net_flush(n);
1397 vhost_dev_stop(&n->dev);
1398 vhost_dev_cleanup(&n->dev);
1399 vhost_net_vq_reset(n);
1400 if (tx_sock)
1401 sockfd_put(tx_sock);
1402 if (rx_sock)
1403 sockfd_put(rx_sock);
1404 /* Make sure no callbacks are outstanding */
1405 synchronize_rcu();
1406 /* We do an extra flush before freeing memory,
1407 * since jobs can re-queue themselves. */
1408 vhost_net_flush(n);
1409 kfree(n->vqs[VHOST_NET_VQ_RX].rxq.queue);
1410 kfree(n->vqs[VHOST_NET_VQ_TX].xdp);
1411 kfree(n->dev.vqs);
1412 if (n->page_frag.page)
1413 __page_frag_cache_drain(n->page_frag.page, n->refcnt_bias);
1414 kvfree(n);
1415 return 0;
1416 }
1417
1418 static struct socket *get_raw_socket(int fd)
1419 {
1420 int r;
1421 struct socket *sock = sockfd_lookup(fd, &r);
1422
1423 if (!sock)
1424 return ERR_PTR(-ENOTSOCK);
1425
1426 /* Parameter checking */
1427 if (sock->sk->sk_type != SOCK_RAW) {
1428 r = -ESOCKTNOSUPPORT;
1429 goto err;
1430 }
1431
1432 if (sock->sk->sk_family != AF_PACKET) {
1433 r = -EPFNOSUPPORT;
1434 goto err;
1435 }
1436 return sock;
1437 err:
1438 sockfd_put(sock);
1439 return ERR_PTR(r);
1440 }
1441
1442 static struct ptr_ring *get_tap_ptr_ring(int fd)
1443 {
1444 struct ptr_ring *ring;
1445 struct file *file = fget(fd);
1446
1447 if (!file)
1448 return NULL;
1449 ring = tun_get_tx_ring(file);
1450 if (!IS_ERR(ring))
1451 goto out;
1452 ring = tap_get_ptr_ring(file);
1453 if (!IS_ERR(ring))
1454 goto out;
1455 ring = NULL;
1456 out:
1457 fput(file);
1458 return ring;
1459 }
1460
1461 static struct socket *get_tap_socket(int fd)
1462 {
1463 struct file *file = fget(fd);
1464 struct socket *sock;
1465
1466 if (!file)
1467 return ERR_PTR(-EBADF);
1468 sock = tun_get_socket(file);
1469 if (!IS_ERR(sock))
1470 return sock;
1471 sock = tap_get_socket(file);
1472 if (IS_ERR(sock))
1473 fput(file);
1474 return sock;
1475 }
1476
1477 static struct socket *get_socket(int fd)
1478 {
1479 struct socket *sock;
1480
1481 /* special case to disable backend */
1482 if (fd == -1)
1483 return NULL;
1484 sock = get_raw_socket(fd);
1485 if (!IS_ERR(sock))
1486 return sock;
1487 sock = get_tap_socket(fd);
1488 if (!IS_ERR(sock))
1489 return sock;
1490 return ERR_PTR(-ENOTSOCK);
1491 }
1492
1493 static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
1494 {
1495 struct socket *sock, *oldsock;
1496 struct vhost_virtqueue *vq;
1497 struct vhost_net_virtqueue *nvq;
1498 struct vhost_net_ubuf_ref *ubufs, *oldubufs = NULL;
1499 int r;
1500
1501 mutex_lock(&n->dev.mutex);
1502 r = vhost_dev_check_owner(&n->dev);
1503 if (r)
1504 goto err;
1505
1506 if (index >= VHOST_NET_VQ_MAX) {
1507 r = -ENOBUFS;
1508 goto err;
1509 }
1510 vq = &n->vqs[index].vq;
1511 nvq = &n->vqs[index];
1512 mutex_lock(&vq->mutex);
1513
1514 /* Verify that ring has been setup correctly. */
1515 if (!vhost_vq_access_ok(vq)) {
1516 r = -EFAULT;
1517 goto err_vq;
1518 }
1519 sock = get_socket(fd);
1520 if (IS_ERR(sock)) {
1521 r = PTR_ERR(sock);
1522 goto err_vq;
1523 }
1524
1525 /* start polling new socket */
1526 oldsock = vhost_vq_get_backend(vq);
1527 if (sock != oldsock) {
1528 ubufs = vhost_net_ubuf_alloc(vq,
1529 sock && vhost_sock_zcopy(sock));
1530 if (IS_ERR(ubufs)) {
1531 r = PTR_ERR(ubufs);
1532 goto err_ubufs;
1533 }
1534
1535 vhost_net_disable_vq(n, vq);
1536 vhost_vq_set_backend(vq, sock);
1537 vhost_net_buf_unproduce(nvq);
1538 r = vhost_vq_init_access(vq);
1539 if (r)
1540 goto err_used;
1541 r = vhost_net_enable_vq(n, vq);
1542 if (r)
1543 goto err_used;
1544 if (index == VHOST_NET_VQ_RX)
1545 nvq->rx_ring = get_tap_ptr_ring(fd);
1546
1547 oldubufs = nvq->ubufs;
1548 nvq->ubufs = ubufs;
1549
1550 n->tx_packets = 0;
1551 n->tx_zcopy_err = 0;
1552 n->tx_flush = false;
1553 }
1554
1555 mutex_unlock(&vq->mutex);
1556
1557 if (oldubufs) {
1558 vhost_net_ubuf_put_wait_and_free(oldubufs);
1559 mutex_lock(&vq->mutex);
1560 vhost_zerocopy_signal_used(n, vq);
1561 mutex_unlock(&vq->mutex);
1562 }
1563
1564 if (oldsock) {
1565 vhost_net_flush_vq(n, index);
1566 sockfd_put(oldsock);
1567 }
1568
1569 mutex_unlock(&n->dev.mutex);
1570 return 0;
1571
1572 err_used:
1573 vhost_vq_set_backend(vq, oldsock);
1574 vhost_net_enable_vq(n, vq);
1575 if (ubufs)
1576 vhost_net_ubuf_put_wait_and_free(ubufs);
1577 err_ubufs:
1578 if (sock)
1579 sockfd_put(sock);
1580 err_vq:
1581 mutex_unlock(&vq->mutex);
1582 err:
1583 mutex_unlock(&n->dev.mutex);
1584 return r;
1585 }
1586
1587 static long vhost_net_reset_owner(struct vhost_net *n)
1588 {
1589 struct socket *tx_sock = NULL;
1590 struct socket *rx_sock = NULL;
1591 long err;
1592 struct vhost_iotlb *umem;
1593
1594 mutex_lock(&n->dev.mutex);
1595 err = vhost_dev_check_owner(&n->dev);
1596 if (err)
1597 goto done;
1598 umem = vhost_dev_reset_owner_prepare();
1599 if (!umem) {
1600 err = -ENOMEM;
1601 goto done;
1602 }
1603 vhost_net_stop(n, &tx_sock, &rx_sock);
1604 vhost_net_flush(n);
1605 vhost_dev_stop(&n->dev);
1606 vhost_dev_reset_owner(&n->dev, umem);
1607 vhost_net_vq_reset(n);
1608 done:
1609 mutex_unlock(&n->dev.mutex);
1610 if (tx_sock)
1611 sockfd_put(tx_sock);
1612 if (rx_sock)
1613 sockfd_put(rx_sock);
1614 return err;
1615 }
1616
1617 static int vhost_net_set_backend_features(struct vhost_net *n, u64 features)
1618 {
1619 int i;
1620
1621 mutex_lock(&n->dev.mutex);
1622 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
1623 mutex_lock(&n->vqs[i].vq.mutex);
1624 n->vqs[i].vq.acked_backend_features = features;
1625 mutex_unlock(&n->vqs[i].vq.mutex);
1626 }
1627 mutex_unlock(&n->dev.mutex);
1628
1629 return 0;
1630 }
1631
1632 static int vhost_net_set_features(struct vhost_net *n, u64 features)
1633 {
1634 size_t vhost_hlen, sock_hlen, hdr_len;
1635 int i;
1636
1637 hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) |
1638 (1ULL << VIRTIO_F_VERSION_1))) ?
1639 sizeof(struct virtio_net_hdr_mrg_rxbuf) :
1640 sizeof(struct virtio_net_hdr);
1641 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) {
1642 /* vhost provides vnet_hdr */
1643 vhost_hlen = hdr_len;
1644 sock_hlen = 0;
1645 } else {
1646 /* socket provides vnet_hdr */
1647 vhost_hlen = 0;
1648 sock_hlen = hdr_len;
1649 }
1650 mutex_lock(&n->dev.mutex);
1651 if ((features & (1 << VHOST_F_LOG_ALL)) &&
1652 !vhost_log_access_ok(&n->dev))
1653 goto out_unlock;
1654
1655 if ((features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))) {
1656 if (vhost_init_device_iotlb(&n->dev, true))
1657 goto out_unlock;
1658 }
1659
1660 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
1661 mutex_lock(&n->vqs[i].vq.mutex);
1662 n->vqs[i].vq.acked_features = features;
1663 n->vqs[i].vhost_hlen = vhost_hlen;
1664 n->vqs[i].sock_hlen = sock_hlen;
1665 mutex_unlock(&n->vqs[i].vq.mutex);
1666 }
1667 mutex_unlock(&n->dev.mutex);
1668 return 0;
1669
1670 out_unlock:
1671 mutex_unlock(&n->dev.mutex);
1672 return -EFAULT;
1673 }
1674
1675 static long vhost_net_set_owner(struct vhost_net *n)
1676 {
1677 int r;
1678
1679 mutex_lock(&n->dev.mutex);
1680 if (vhost_dev_has_owner(&n->dev)) {
1681 r = -EBUSY;
1682 goto out;
1683 }
1684 r = vhost_net_set_ubuf_info(n);
1685 if (r)
1686 goto out;
1687 r = vhost_dev_set_owner(&n->dev);
1688 if (r)
1689 vhost_net_clear_ubuf_info(n);
1690 vhost_net_flush(n);
1691 out:
1692 mutex_unlock(&n->dev.mutex);
1693 return r;
1694 }
1695
1696 static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
1697 unsigned long arg)
1698 {
1699 struct vhost_net *n = f->private_data;
1700 void __user *argp = (void __user *)arg;
1701 u64 __user *featurep = argp;
1702 struct vhost_vring_file backend;
1703 u64 features;
1704 int r;
1705
1706 switch (ioctl) {
1707 case VHOST_NET_SET_BACKEND:
1708 if (copy_from_user(&backend, argp, sizeof backend))
1709 return -EFAULT;
1710 return vhost_net_set_backend(n, backend.index, backend.fd);
1711 case VHOST_GET_FEATURES:
1712 features = VHOST_NET_FEATURES;
1713 if (copy_to_user(featurep, &features, sizeof features))
1714 return -EFAULT;
1715 return 0;
1716 case VHOST_SET_FEATURES:
1717 if (copy_from_user(&features, featurep, sizeof features))
1718 return -EFAULT;
1719 if (features & ~VHOST_NET_FEATURES)
1720 return -EOPNOTSUPP;
1721 return vhost_net_set_features(n, features);
1722 case VHOST_GET_BACKEND_FEATURES:
1723 features = VHOST_NET_BACKEND_FEATURES;
1724 if (copy_to_user(featurep, &features, sizeof(features)))
1725 return -EFAULT;
1726 return 0;
1727 case VHOST_SET_BACKEND_FEATURES:
1728 if (copy_from_user(&features, featurep, sizeof(features)))
1729 return -EFAULT;
1730 if (features & ~VHOST_NET_BACKEND_FEATURES)
1731 return -EOPNOTSUPP;
1732 return vhost_net_set_backend_features(n, features);
1733 case VHOST_RESET_OWNER:
1734 return vhost_net_reset_owner(n);
1735 case VHOST_SET_OWNER:
1736 return vhost_net_set_owner(n);
1737 default:
1738 mutex_lock(&n->dev.mutex);
1739 r = vhost_dev_ioctl(&n->dev, ioctl, argp);
1740 if (r == -ENOIOCTLCMD)
1741 r = vhost_vring_ioctl(&n->dev, ioctl, argp);
1742 else
1743 vhost_net_flush(n);
1744 mutex_unlock(&n->dev.mutex);
1745 return r;
1746 }
1747 }
1748
1749 static ssize_t vhost_net_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1750 {
1751 struct file *file = iocb->ki_filp;
1752 struct vhost_net *n = file->private_data;
1753 struct vhost_dev *dev = &n->dev;
1754 int noblock = file->f_flags & O_NONBLOCK;
1755
1756 return vhost_chr_read_iter(dev, to, noblock);
1757 }
1758
1759 static ssize_t vhost_net_chr_write_iter(struct kiocb *iocb,
1760 struct iov_iter *from)
1761 {
1762 struct file *file = iocb->ki_filp;
1763 struct vhost_net *n = file->private_data;
1764 struct vhost_dev *dev = &n->dev;
1765
1766 return vhost_chr_write_iter(dev, from);
1767 }
1768
1769 static __poll_t vhost_net_chr_poll(struct file *file, poll_table *wait)
1770 {
1771 struct vhost_net *n = file->private_data;
1772 struct vhost_dev *dev = &n->dev;
1773
1774 return vhost_chr_poll(file, dev, wait);
1775 }
1776
1777 static const struct file_operations vhost_net_fops = {
1778 .owner = THIS_MODULE,
1779 .release = vhost_net_release,
1780 .read_iter = vhost_net_chr_read_iter,
1781 .write_iter = vhost_net_chr_write_iter,
1782 .poll = vhost_net_chr_poll,
1783 .unlocked_ioctl = vhost_net_ioctl,
1784 .compat_ioctl = compat_ptr_ioctl,
1785 .open = vhost_net_open,
1786 .llseek = noop_llseek,
1787 };
1788
1789 static struct miscdevice vhost_net_misc = {
1790 .minor = VHOST_NET_MINOR,
1791 .name = "vhost-net",
1792 .fops = &vhost_net_fops,
1793 };
1794
1795 static int vhost_net_init(void)
1796 {
1797 if (experimental_zcopytx)
1798 vhost_net_enable_zcopy(VHOST_NET_VQ_TX);
1799 return misc_register(&vhost_net_misc);
1800 }
1801 module_init(vhost_net_init);
1802
1803 static void vhost_net_exit(void)
1804 {
1805 misc_deregister(&vhost_net_misc);
1806 }
1807 module_exit(vhost_net_exit);
1808
1809 MODULE_VERSION("0.0.1");
1810 MODULE_LICENSE("GPL v2");
1811 MODULE_AUTHOR("Michael S. Tsirkin");
1812 MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
1813 MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR);
1814 MODULE_ALIAS("devname:vhost-net");
Linux with added FPC-III support