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Linux 5.1.15
[linux/fpc-iii.git] / drivers / vhost / net.c
blobdf51a35cf537c96caf570d0ce06dbbc004b61af1
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/file.h>
19 #include <linux/slab.h>
20 #include <linux/sched/clock.h>
21 #include <linux/sched/signal.h>
22 #include <linux/vmalloc.h>
23
24 #include <linux/net.h>
25 #include <linux/if_packet.h>
26 #include <linux/if_arp.h>
27 #include <linux/if_tun.h>
28 #include <linux/if_macvlan.h>
29 #include <linux/if_tap.h>
30 #include <linux/if_vlan.h>
31 #include <linux/skb_array.h>
32 #include <linux/skbuff.h>
33
34 #include <net/sock.h>
35 #include <net/xdp.h>
36
37 #include "vhost.h"
38
39 static int experimental_zcopytx = 1;
40 module_param(experimental_zcopytx, int, 0444);
41 MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;"
42 " 1 -Enable; 0 - Disable");
43
44 /* Max number of bytes transferred before requeueing the job.
45 * Using this limit prevents one virtqueue from starving others. */
46 #define VHOST_NET_WEIGHT 0x80000
47
48 /* Max number of packets transferred before requeueing the job.
49 * Using this limit prevents one virtqueue from starving others with small
50 * pkts.
51 */
52 #define VHOST_NET_PKT_WEIGHT 256
53
54 /* MAX number of TX used buffers for outstanding zerocopy */
55 #define VHOST_MAX_PEND 128
56 #define VHOST_GOODCOPY_LEN 256
57
58 /*
59 * For transmit, used buffer len is unused; we override it to track buffer
60 * status internally; used for zerocopy tx only.
61 */
62 /* Lower device DMA failed */
63 #define VHOST_DMA_FAILED_LEN ((__force __virtio32)3)
64 /* Lower device DMA done */
65 #define VHOST_DMA_DONE_LEN ((__force __virtio32)2)
66 /* Lower device DMA in progress */
67 #define VHOST_DMA_IN_PROGRESS ((__force __virtio32)1)
68 /* Buffer unused */
69 #define VHOST_DMA_CLEAR_LEN ((__force __virtio32)0)
70
71 #define VHOST_DMA_IS_DONE(len) ((__force u32)(len) >= (__force u32)VHOST_DMA_DONE_LEN)
72
73 enum {
74 VHOST_NET_FEATURES = VHOST_FEATURES |
75 (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |
76 (1ULL << VIRTIO_NET_F_MRG_RXBUF) |
77 (1ULL << VIRTIO_F_IOMMU_PLATFORM)
78 };
79
80 enum {
81 VHOST_NET_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2)
82 };
83
84 enum {
85 VHOST_NET_VQ_RX = 0,
86 VHOST_NET_VQ_TX = 1,
87 VHOST_NET_VQ_MAX = 2,
88 };
89
90 struct vhost_net_ubuf_ref {
91 /* refcount follows semantics similar to kref:
92 * 0: object is released
93 * 1: no outstanding ubufs
94 * >1: outstanding ubufs
95 */
96 atomic_t refcount;
97 wait_queue_head_t wait;
98 struct vhost_virtqueue *vq;
99 };
100
101 #define VHOST_NET_BATCH 64
102 struct vhost_net_buf {
103 void **queue;
104 int tail;
105 int head;
106 };
107
108 struct vhost_net_virtqueue {
109 struct vhost_virtqueue vq;
110 size_t vhost_hlen;
111 size_t sock_hlen;
112 /* vhost zerocopy support fields below: */
113 /* last used idx for outstanding DMA zerocopy buffers */
114 int upend_idx;
115 /* For TX, first used idx for DMA done zerocopy buffers
116 * For RX, number of batched heads
117 */
118 int done_idx;
119 /* Number of XDP frames batched */
120 int batched_xdp;
121 /* an array of userspace buffers info */
122 struct ubuf_info *ubuf_info;
123 /* Reference counting for outstanding ubufs.
124 * Protected by vq mutex. Writers must also take device mutex. */
125 struct vhost_net_ubuf_ref *ubufs;
126 struct ptr_ring *rx_ring;
127 struct vhost_net_buf rxq;
128 /* Batched XDP buffs */
129 struct xdp_buff *xdp;
130 };
131
132 struct vhost_net {
133 struct vhost_dev dev;
134 struct vhost_net_virtqueue vqs[VHOST_NET_VQ_MAX];
135 struct vhost_poll poll[VHOST_NET_VQ_MAX];
136 /* Number of TX recently submitted.
137 * Protected by tx vq lock. */
138 unsigned tx_packets;
139 /* Number of times zerocopy TX recently failed.
140 * Protected by tx vq lock. */
141 unsigned tx_zcopy_err;
142 /* Flush in progress. Protected by tx vq lock. */
143 bool tx_flush;
144 /* Private page frag */
145 struct page_frag page_frag;
146 /* Refcount bias of page frag */
147 int refcnt_bias;
148 };
149
150 static unsigned vhost_net_zcopy_mask __read_mostly;
151
152 static void *vhost_net_buf_get_ptr(struct vhost_net_buf *rxq)
153 {
154 if (rxq->tail != rxq->head)
155 return rxq->queue[rxq->head];
156 else
157 return NULL;
158 }
159
160 static int vhost_net_buf_get_size(struct vhost_net_buf *rxq)
161 {
162 return rxq->tail - rxq->head;
163 }
164
165 static int vhost_net_buf_is_empty(struct vhost_net_buf *rxq)
166 {
167 return rxq->tail == rxq->head;
168 }
169
170 static void *vhost_net_buf_consume(struct vhost_net_buf *rxq)
171 {
172 void *ret = vhost_net_buf_get_ptr(rxq);
173 ++rxq->head;
174 return ret;
175 }
176
177 static int vhost_net_buf_produce(struct vhost_net_virtqueue *nvq)
178 {
179 struct vhost_net_buf *rxq = &nvq->rxq;
180
181 rxq->head = 0;
182 rxq->tail = ptr_ring_consume_batched(nvq->rx_ring, rxq->queue,
183 VHOST_NET_BATCH);
184 return rxq->tail;
185 }
186
187 static void vhost_net_buf_unproduce(struct vhost_net_virtqueue *nvq)
188 {
189 struct vhost_net_buf *rxq = &nvq->rxq;
190
191 if (nvq->rx_ring && !vhost_net_buf_is_empty(rxq)) {
192 ptr_ring_unconsume(nvq->rx_ring, rxq->queue + rxq->head,
193 vhost_net_buf_get_size(rxq),
194 tun_ptr_free);
195 rxq->head = rxq->tail = 0;
196 }
197 }
198
199 static int vhost_net_buf_peek_len(void *ptr)
200 {
201 if (tun_is_xdp_frame(ptr)) {
202 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
203
204 return xdpf->len;
205 }
206
207 return __skb_array_len_with_tag(ptr);
208 }
209
210 static int vhost_net_buf_peek(struct vhost_net_virtqueue *nvq)
211 {
212 struct vhost_net_buf *rxq = &nvq->rxq;
213
214 if (!vhost_net_buf_is_empty(rxq))
215 goto out;
216
217 if (!vhost_net_buf_produce(nvq))
218 return 0;
219
220 out:
221 return vhost_net_buf_peek_len(vhost_net_buf_get_ptr(rxq));
222 }
223
224 static void vhost_net_buf_init(struct vhost_net_buf *rxq)
225 {
226 rxq->head = rxq->tail = 0;
227 }
228
229 static void vhost_net_enable_zcopy(int vq)
230 {
231 vhost_net_zcopy_mask |= 0x1 << vq;
232 }
233
234 static struct vhost_net_ubuf_ref *
235 vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy)
236 {
237 struct vhost_net_ubuf_ref *ubufs;
238 /* No zero copy backend? Nothing to count. */
239 if (!zcopy)
240 return NULL;
241 ubufs = kmalloc(sizeof(*ubufs), GFP_KERNEL);
242 if (!ubufs)
243 return ERR_PTR(-ENOMEM);
244 atomic_set(&ubufs->refcount, 1);
245 init_waitqueue_head(&ubufs->wait);
246 ubufs->vq = vq;
247 return ubufs;
248 }
249
250 static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs)
251 {
252 int r = atomic_sub_return(1, &ubufs->refcount);
253 if (unlikely(!r))
254 wake_up(&ubufs->wait);
255 return r;
256 }
257
258 static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs)
259 {
260 vhost_net_ubuf_put(ubufs);
261 wait_event(ubufs->wait, !atomic_read(&ubufs->refcount));
262 }
263
264 static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs)
265 {
266 vhost_net_ubuf_put_and_wait(ubufs);
267 kfree(ubufs);
268 }
269
270 static void vhost_net_clear_ubuf_info(struct vhost_net *n)
271 {
272 int i;
273
274 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
275 kfree(n->vqs[i].ubuf_info);
276 n->vqs[i].ubuf_info = NULL;
277 }
278 }
279
280 static int vhost_net_set_ubuf_info(struct vhost_net *n)
281 {
282 bool zcopy;
283 int i;
284
285 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
286 zcopy = vhost_net_zcopy_mask & (0x1 << i);
287 if (!zcopy)
288 continue;
289 n->vqs[i].ubuf_info =
290 kmalloc_array(UIO_MAXIOV,
291 sizeof(*n->vqs[i].ubuf_info),
292 GFP_KERNEL);
293 if (!n->vqs[i].ubuf_info)
294 goto err;
295 }
296 return 0;
297
298 err:
299 vhost_net_clear_ubuf_info(n);
300 return -ENOMEM;
301 }
302
303 static void vhost_net_vq_reset(struct vhost_net *n)
304 {
305 int i;
306
307 vhost_net_clear_ubuf_info(n);
308
309 for (i = 0; i < VHOST_NET_VQ_MAX; i++) {
310 n->vqs[i].done_idx = 0;
311 n->vqs[i].upend_idx = 0;
312 n->vqs[i].ubufs = NULL;
313 n->vqs[i].vhost_hlen = 0;
314 n->vqs[i].sock_hlen = 0;
315 vhost_net_buf_init(&n->vqs[i].rxq);
316 }
317
318 }
319
320 static void vhost_net_tx_packet(struct vhost_net *net)
321 {
322 ++net->tx_packets;
323 if (net->tx_packets < 1024)
324 return;
325 net->tx_packets = 0;
326 net->tx_zcopy_err = 0;
327 }
328
329 static void vhost_net_tx_err(struct vhost_net *net)
330 {
331 ++net->tx_zcopy_err;
332 }
333
334 static bool vhost_net_tx_select_zcopy(struct vhost_net *net)
335 {
336 /* TX flush waits for outstanding DMAs to be done.
337 * Don't start new DMAs.
338 */
339 return !net->tx_flush &&
340 net->tx_packets / 64 >= net->tx_zcopy_err;
341 }
342
343 static bool vhost_sock_zcopy(struct socket *sock)
344 {
345 return unlikely(experimental_zcopytx) &&
346 sock_flag(sock->sk, SOCK_ZEROCOPY);
347 }
348
349 static bool vhost_sock_xdp(struct socket *sock)
350 {
351 return sock_flag(sock->sk, SOCK_XDP);
352 }
353
354 /* In case of DMA done not in order in lower device driver for some reason.
355 * upend_idx is used to track end of used idx, done_idx is used to track head
356 * of used idx. Once lower device DMA done contiguously, we will signal KVM
357 * guest used idx.
358 */
359 static void vhost_zerocopy_signal_used(struct vhost_net *net,
360 struct vhost_virtqueue *vq)
361 {
362 struct vhost_net_virtqueue *nvq =
363 container_of(vq, struct vhost_net_virtqueue, vq);
364 int i, add;
365 int j = 0;
366
367 for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) {
368 if (vq->heads[i].len == VHOST_DMA_FAILED_LEN)
369 vhost_net_tx_err(net);
370 if (VHOST_DMA_IS_DONE(vq->heads[i].len)) {
371 vq->heads[i].len = VHOST_DMA_CLEAR_LEN;
372 ++j;
373 } else
374 break;
375 }
376 while (j) {
377 add = min(UIO_MAXIOV - nvq->done_idx, j);
378 vhost_add_used_and_signal_n(vq->dev, vq,
379 &vq->heads[nvq->done_idx], add);
380 nvq->done_idx = (nvq->done_idx + add) % UIO_MAXIOV;
381 j -= add;
382 }
383 }
384
385 static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success)
386 {
387 struct vhost_net_ubuf_ref *ubufs = ubuf->ctx;
388 struct vhost_virtqueue *vq = ubufs->vq;
389 int cnt;
390
391 rcu_read_lock_bh();
392
393 /* set len to mark this desc buffers done DMA */
394 vq->heads[ubuf->desc].len = success ?
395 VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN;
396 cnt = vhost_net_ubuf_put(ubufs);
397
398 /*
399 * Trigger polling thread if guest stopped submitting new buffers:
400 * in this case, the refcount after decrement will eventually reach 1.
401 * We also trigger polling periodically after each 16 packets
402 * (the value 16 here is more or less arbitrary, it's tuned to trigger
403 * less than 10% of times).
404 */
405 if (cnt <= 1 || !(cnt % 16))
406 vhost_poll_queue(&vq->poll);
407
408 rcu_read_unlock_bh();
409 }
410
411 static inline unsigned long busy_clock(void)
412 {
413 return local_clock() >> 10;
414 }
415
416 static bool vhost_can_busy_poll(unsigned long endtime)
417 {
418 return likely(!need_resched() && !time_after(busy_clock(), endtime) &&
419 !signal_pending(current));
420 }
421
422 static void vhost_net_disable_vq(struct vhost_net *n,
423 struct vhost_virtqueue *vq)
424 {
425 struct vhost_net_virtqueue *nvq =
426 container_of(vq, struct vhost_net_virtqueue, vq);
427 struct vhost_poll *poll = n->poll + (nvq - n->vqs);
428 if (!vq->private_data)
429 return;
430 vhost_poll_stop(poll);
431 }
432
433 static int vhost_net_enable_vq(struct vhost_net *n,
434 struct vhost_virtqueue *vq)
435 {
436 struct vhost_net_virtqueue *nvq =
437 container_of(vq, struct vhost_net_virtqueue, vq);
438 struct vhost_poll *poll = n->poll + (nvq - n->vqs);
439 struct socket *sock;
440
441 sock = vq->private_data;
442 if (!sock)
443 return 0;
444
445 return vhost_poll_start(poll, sock->file);
446 }
447
448 static void vhost_net_signal_used(struct vhost_net_virtqueue *nvq)
449 {
450 struct vhost_virtqueue *vq = &nvq->vq;
451 struct vhost_dev *dev = vq->dev;
452
453 if (!nvq->done_idx)
454 return;
455
456 vhost_add_used_and_signal_n(dev, vq, vq->heads, nvq->done_idx);
457 nvq->done_idx = 0;
458 }
459
460 static void vhost_tx_batch(struct vhost_net *net,
461 struct vhost_net_virtqueue *nvq,
462 struct socket *sock,
463 struct msghdr *msghdr)
464 {
465 struct tun_msg_ctl ctl = {
466 .type = TUN_MSG_PTR,
467 .num = nvq->batched_xdp,
468 .ptr = nvq->xdp,
469 };
470 int err;
471
472 if (nvq->batched_xdp == 0)
473 goto signal_used;
474
475 msghdr->msg_control = &ctl;
476 err = sock->ops->sendmsg(sock, msghdr, 0);
477 if (unlikely(err < 0)) {
478 vq_err(&nvq->vq, "Fail to batch sending packets\n");
479 return;
480 }
481
482 signal_used:
483 vhost_net_signal_used(nvq);
484 nvq->batched_xdp = 0;
485 }
486
487 static int sock_has_rx_data(struct socket *sock)
488 {
489 if (unlikely(!sock))
490 return 0;
491
492 if (sock->ops->peek_len)
493 return sock->ops->peek_len(sock);
494
495 return skb_queue_empty(&sock->sk->sk_receive_queue);
496 }
497
498 static void vhost_net_busy_poll_try_queue(struct vhost_net *net,
499 struct vhost_virtqueue *vq)
500 {
501 if (!vhost_vq_avail_empty(&net->dev, vq)) {
502 vhost_poll_queue(&vq->poll);
503 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) {
504 vhost_disable_notify(&net->dev, vq);
505 vhost_poll_queue(&vq->poll);
506 }
507 }
508
509 static void vhost_net_busy_poll(struct vhost_net *net,
510 struct vhost_virtqueue *rvq,
511 struct vhost_virtqueue *tvq,
512 bool *busyloop_intr,
513 bool poll_rx)
514 {
515 unsigned long busyloop_timeout;
516 unsigned long endtime;
517 struct socket *sock;
518 struct vhost_virtqueue *vq = poll_rx ? tvq : rvq;
519
520 /* Try to hold the vq mutex of the paired virtqueue. We can't
521 * use mutex_lock() here since we could not guarantee a
522 * consistenet lock ordering.
523 */
524 if (!mutex_trylock(&vq->mutex))
525 return;
526
527 vhost_disable_notify(&net->dev, vq);
528 sock = rvq->private_data;
529
530 busyloop_timeout = poll_rx ? rvq->busyloop_timeout:
531 tvq->busyloop_timeout;
532
533 preempt_disable();
534 endtime = busy_clock() + busyloop_timeout;
535
536 while (vhost_can_busy_poll(endtime)) {
537 if (vhost_has_work(&net->dev)) {
538 *busyloop_intr = true;
539 break;
540 }
541
542 if ((sock_has_rx_data(sock) &&
543 !vhost_vq_avail_empty(&net->dev, rvq)) ||
544 !vhost_vq_avail_empty(&net->dev, tvq))
545 break;
546
547 cpu_relax();
548 }
549
550 preempt_enable();
551
552 if (poll_rx || sock_has_rx_data(sock))
553 vhost_net_busy_poll_try_queue(net, vq);
554 else if (!poll_rx) /* On tx here, sock has no rx data. */
555 vhost_enable_notify(&net->dev, rvq);
556
557 mutex_unlock(&vq->mutex);
558 }
559
560 static int vhost_net_tx_get_vq_desc(struct vhost_net *net,
561 struct vhost_net_virtqueue *tnvq,
562 unsigned int *out_num, unsigned int *in_num,
563 struct msghdr *msghdr, bool *busyloop_intr)
564 {
565 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX];
566 struct vhost_virtqueue *rvq = &rnvq->vq;
567 struct vhost_virtqueue *tvq = &tnvq->vq;
568
569 int r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov),
570 out_num, in_num, NULL, NULL);
571
572 if (r == tvq->num && tvq->busyloop_timeout) {
573 /* Flush batched packets first */
574 if (!vhost_sock_zcopy(tvq->private_data))
575 vhost_tx_batch(net, tnvq, tvq->private_data, msghdr);
576
577 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, false);
578
579 r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov),
580 out_num, in_num, NULL, NULL);
581 }
582
583 return r;
584 }
585
586 static bool vhost_exceeds_maxpend(struct vhost_net *net)
587 {
588 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
589 struct vhost_virtqueue *vq = &nvq->vq;
590
591 return (nvq->upend_idx + UIO_MAXIOV - nvq->done_idx) % UIO_MAXIOV >
592 min_t(unsigned int, VHOST_MAX_PEND, vq->num >> 2);
593 }
594
595 static size_t init_iov_iter(struct vhost_virtqueue *vq, struct iov_iter *iter,
596 size_t hdr_size, int out)
597 {
598 /* Skip header. TODO: support TSO. */
599 size_t len = iov_length(vq->iov, out);
600
601 iov_iter_init(iter, WRITE, vq->iov, out, len);
602 iov_iter_advance(iter, hdr_size);
603
604 return iov_iter_count(iter);
605 }
606
607 static bool vhost_exceeds_weight(int pkts, int total_len)
608 {
609 return total_len >= VHOST_NET_WEIGHT ||
610 pkts >= VHOST_NET_PKT_WEIGHT;
611 }
612
613 static int get_tx_bufs(struct vhost_net *net,
614 struct vhost_net_virtqueue *nvq,
615 struct msghdr *msg,
616 unsigned int *out, unsigned int *in,
617 size_t *len, bool *busyloop_intr)
618 {
619 struct vhost_virtqueue *vq = &nvq->vq;
620 int ret;
621
622 ret = vhost_net_tx_get_vq_desc(net, nvq, out, in, msg, busyloop_intr);
623
624 if (ret < 0 || ret == vq->num)
625 return ret;
626
627 if (*in) {
628 vq_err(vq, "Unexpected descriptor format for TX: out %d, int %d\n",
629 *out, *in);
630 return -EFAULT;
631 }
632
633 /* Sanity check */
634 *len = init_iov_iter(vq, &msg->msg_iter, nvq->vhost_hlen, *out);
635 if (*len == 0) {
636 vq_err(vq, "Unexpected header len for TX: %zd expected %zd\n",
637 *len, nvq->vhost_hlen);
638 return -EFAULT;
639 }
640
641 return ret;
642 }
643
644 static bool tx_can_batch(struct vhost_virtqueue *vq, size_t total_len)
645 {
646 return total_len < VHOST_NET_WEIGHT &&
647 !vhost_vq_avail_empty(vq->dev, vq);
648 }
649
650 #define SKB_FRAG_PAGE_ORDER get_order(32768)
651
652 static bool vhost_net_page_frag_refill(struct vhost_net *net, unsigned int sz,
653 struct page_frag *pfrag, gfp_t gfp)
654 {
655 if (pfrag->page) {
656 if (pfrag->offset + sz <= pfrag->size)
657 return true;
658 __page_frag_cache_drain(pfrag->page, net->refcnt_bias);
659 }
660
661 pfrag->offset = 0;
662 net->refcnt_bias = 0;
663 if (SKB_FRAG_PAGE_ORDER) {
664 /* Avoid direct reclaim but allow kswapd to wake */
665 pfrag->page = alloc_pages((gfp & ~__GFP_DIRECT_RECLAIM) |
666 __GFP_COMP | __GFP_NOWARN |
667 __GFP_NORETRY,
668 SKB_FRAG_PAGE_ORDER);
669 if (likely(pfrag->page)) {
670 pfrag->size = PAGE_SIZE << SKB_FRAG_PAGE_ORDER;
671 goto done;
672 }
673 }
674 pfrag->page = alloc_page(gfp);
675 if (likely(pfrag->page)) {
676 pfrag->size = PAGE_SIZE;
677 goto done;
678 }
679 return false;
680
681 done:
682 net->refcnt_bias = USHRT_MAX;
683 page_ref_add(pfrag->page, USHRT_MAX - 1);
684 return true;
685 }
686
687 #define VHOST_NET_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
688
689 static int vhost_net_build_xdp(struct vhost_net_virtqueue *nvq,
690 struct iov_iter *from)
691 {
692 struct vhost_virtqueue *vq = &nvq->vq;
693 struct vhost_net *net = container_of(vq->dev, struct vhost_net,
694 dev);
695 struct socket *sock = vq->private_data;
696 struct page_frag *alloc_frag = &net->page_frag;
697 struct virtio_net_hdr *gso;
698 struct xdp_buff *xdp = &nvq->xdp[nvq->batched_xdp];
699 struct tun_xdp_hdr *hdr;
700 size_t len = iov_iter_count(from);
701 int headroom = vhost_sock_xdp(sock) ? XDP_PACKET_HEADROOM : 0;
702 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
703 int pad = SKB_DATA_ALIGN(VHOST_NET_RX_PAD + headroom + nvq->sock_hlen);
704 int sock_hlen = nvq->sock_hlen;
705 void *buf;
706 int copied;
707
708 if (unlikely(len < nvq->sock_hlen))
709 return -EFAULT;
710
711 if (SKB_DATA_ALIGN(len + pad) +
712 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
713 return -ENOSPC;
714
715 buflen += SKB_DATA_ALIGN(len + pad);
716 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES);
717 if (unlikely(!vhost_net_page_frag_refill(net, buflen,
718 alloc_frag, GFP_KERNEL)))
719 return -ENOMEM;
720
721 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset;
722 copied = copy_page_from_iter(alloc_frag->page,
723 alloc_frag->offset +
724 offsetof(struct tun_xdp_hdr, gso),
725 sock_hlen, from);
726 if (copied != sock_hlen)
727 return -EFAULT;
728
729 hdr = buf;
730 gso = &hdr->gso;
731
732 if ((gso->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
733 vhost16_to_cpu(vq, gso->csum_start) +
734 vhost16_to_cpu(vq, gso->csum_offset) + 2 >
735 vhost16_to_cpu(vq, gso->hdr_len)) {
736 gso->hdr_len = cpu_to_vhost16(vq,
737 vhost16_to_cpu(vq, gso->csum_start) +
738 vhost16_to_cpu(vq, gso->csum_offset) + 2);
739
740 if (vhost16_to_cpu(vq, gso->hdr_len) > len)
741 return -EINVAL;
742 }
743
744 len -= sock_hlen;
745 copied = copy_page_from_iter(alloc_frag->page,
746 alloc_frag->offset + pad,
747 len, from);
748 if (copied != len)
749 return -EFAULT;
750
751 xdp->data_hard_start = buf;
752 xdp->data = buf + pad;
753 xdp->data_end = xdp->data + len;
754 hdr->buflen = buflen;
755
756 --net->refcnt_bias;
757 alloc_frag->offset += buflen;
758
759 ++nvq->batched_xdp;
760
761 return 0;
762 }
763
764 static void handle_tx_copy(struct vhost_net *net, struct socket *sock)
765 {
766 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
767 struct vhost_virtqueue *vq = &nvq->vq;
768 unsigned out, in;
769 int head;
770 struct msghdr msg = {
771 .msg_name = NULL,
772 .msg_namelen = 0,
773 .msg_control = NULL,
774 .msg_controllen = 0,
775 .msg_flags = MSG_DONTWAIT,
776 };
777 size_t len, total_len = 0;
778 int err;
779 int sent_pkts = 0;
780 bool sock_can_batch = (sock->sk->sk_sndbuf == INT_MAX);
781
782 for (;;) {
783 bool busyloop_intr = false;
784
785 if (nvq->done_idx == VHOST_NET_BATCH)
786 vhost_tx_batch(net, nvq, sock, &msg);
787
788 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len,
789 &busyloop_intr);
790 /* On error, stop handling until the next kick. */
791 if (unlikely(head < 0))
792 break;
793 /* Nothing new? Wait for eventfd to tell us they refilled. */
794 if (head == vq->num) {
795 if (unlikely(busyloop_intr)) {
796 vhost_poll_queue(&vq->poll);
797 } else if (unlikely(vhost_enable_notify(&net->dev,
798 vq))) {
799 vhost_disable_notify(&net->dev, vq);
800 continue;
801 }
802 break;
803 }
804
805 total_len += len;
806
807 /* For simplicity, TX batching is only enabled if
808 * sndbuf is unlimited.
809 */
810 if (sock_can_batch) {
811 err = vhost_net_build_xdp(nvq, &msg.msg_iter);
812 if (!err) {
813 goto done;
814 } else if (unlikely(err != -ENOSPC)) {
815 vhost_tx_batch(net, nvq, sock, &msg);
816 vhost_discard_vq_desc(vq, 1);
817 vhost_net_enable_vq(net, vq);
818 break;
819 }
820
821 /* We can't build XDP buff, go for single
822 * packet path but let's flush batched
823 * packets.
824 */
825 vhost_tx_batch(net, nvq, sock, &msg);
826 msg.msg_control = NULL;
827 } else {
828 if (tx_can_batch(vq, total_len))
829 msg.msg_flags |= MSG_MORE;
830 else
831 msg.msg_flags &= ~MSG_MORE;
832 }
833
834 /* TODO: Check specific error and bomb out unless ENOBUFS? */
835 err = sock->ops->sendmsg(sock, &msg, len);
836 if (unlikely(err < 0)) {
837 vhost_discard_vq_desc(vq, 1);
838 vhost_net_enable_vq(net, vq);
839 break;
840 }
841 if (err != len)
842 pr_debug("Truncated TX packet: len %d != %zd\n",
843 err, len);
844 done:
845 vq->heads[nvq->done_idx].id = cpu_to_vhost32(vq, head);
846 vq->heads[nvq->done_idx].len = 0;
847 ++nvq->done_idx;
848 if (vhost_exceeds_weight(++sent_pkts, total_len)) {
849 vhost_poll_queue(&vq->poll);
850 break;
851 }
852 }
853
854 vhost_tx_batch(net, nvq, sock, &msg);
855 }
856
857 static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock)
858 {
859 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
860 struct vhost_virtqueue *vq = &nvq->vq;
861 unsigned out, in;
862 int head;
863 struct msghdr msg = {
864 .msg_name = NULL,
865 .msg_namelen = 0,
866 .msg_control = NULL,
867 .msg_controllen = 0,
868 .msg_flags = MSG_DONTWAIT,
869 };
870 struct tun_msg_ctl ctl;
871 size_t len, total_len = 0;
872 int err;
873 struct vhost_net_ubuf_ref *uninitialized_var(ubufs);
874 bool zcopy_used;
875 int sent_pkts = 0;
876
877 for (;;) {
878 bool busyloop_intr;
879
880 /* Release DMAs done buffers first */
881 vhost_zerocopy_signal_used(net, vq);
882
883 busyloop_intr = false;
884 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len,
885 &busyloop_intr);
886 /* On error, stop handling until the next kick. */
887 if (unlikely(head < 0))
888 break;
889 /* Nothing new? Wait for eventfd to tell us they refilled. */
890 if (head == vq->num) {
891 if (unlikely(busyloop_intr)) {
892 vhost_poll_queue(&vq->poll);
893 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) {
894 vhost_disable_notify(&net->dev, vq);
895 continue;
896 }
897 break;
898 }
899
900 zcopy_used = len >= VHOST_GOODCOPY_LEN
901 && !vhost_exceeds_maxpend(net)
902 && vhost_net_tx_select_zcopy(net);
903
904 /* use msg_control to pass vhost zerocopy ubuf info to skb */
905 if (zcopy_used) {
906 struct ubuf_info *ubuf;
907 ubuf = nvq->ubuf_info + nvq->upend_idx;
908
909 vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head);
910 vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS;
911 ubuf->callback = vhost_zerocopy_callback;
912 ubuf->ctx = nvq->ubufs;
913 ubuf->desc = nvq->upend_idx;
914 refcount_set(&ubuf->refcnt, 1);
915 msg.msg_control = &ctl;
916 ctl.type = TUN_MSG_UBUF;
917 ctl.ptr = ubuf;
918 msg.msg_controllen = sizeof(ctl);
919 ubufs = nvq->ubufs;
920 atomic_inc(&ubufs->refcount);
921 nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV;
922 } else {
923 msg.msg_control = NULL;
924 ubufs = NULL;
925 }
926 total_len += len;
927 if (tx_can_batch(vq, total_len) &&
928 likely(!vhost_exceeds_maxpend(net))) {
929 msg.msg_flags |= MSG_MORE;
930 } else {
931 msg.msg_flags &= ~MSG_MORE;
932 }
933
934 /* TODO: Check specific error and bomb out unless ENOBUFS? */
935 err = sock->ops->sendmsg(sock, &msg, len);
936 if (unlikely(err < 0)) {
937 if (zcopy_used) {
938 vhost_net_ubuf_put(ubufs);
939 nvq->upend_idx = ((unsigned)nvq->upend_idx - 1)
940 % UIO_MAXIOV;
941 }
942 vhost_discard_vq_desc(vq, 1);
943 vhost_net_enable_vq(net, vq);
944 break;
945 }
946 if (err != len)
947 pr_debug("Truncated TX packet: "
948 " len %d != %zd\n", err, len);
949 if (!zcopy_used)
950 vhost_add_used_and_signal(&net->dev, vq, head, 0);
951 else
952 vhost_zerocopy_signal_used(net, vq);
953 vhost_net_tx_packet(net);
954 if (unlikely(vhost_exceeds_weight(++sent_pkts, total_len))) {
955 vhost_poll_queue(&vq->poll);
956 break;
957 }
958 }
959 }
960
961 /* Expects to be always run from workqueue - which acts as
962 * read-size critical section for our kind of RCU. */
963 static void handle_tx(struct vhost_net *net)
964 {
965 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
966 struct vhost_virtqueue *vq = &nvq->vq;
967 struct socket *sock;
968
969 mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_TX);
970 sock = vq->private_data;
971 if (!sock)
972 goto out;
973
974 if (!vq_iotlb_prefetch(vq))
975 goto out;
976
977 vhost_disable_notify(&net->dev, vq);
978 vhost_net_disable_vq(net, vq);
979
980 if (vhost_sock_zcopy(sock))
981 handle_tx_zerocopy(net, sock);
982 else
983 handle_tx_copy(net, sock);
984
985 out:
986 mutex_unlock(&vq->mutex);
987 }
988
989 static int peek_head_len(struct vhost_net_virtqueue *rvq, struct sock *sk)
990 {
991 struct sk_buff *head;
992 int len = 0;
993 unsigned long flags;
994
995 if (rvq->rx_ring)
996 return vhost_net_buf_peek(rvq);
997
998 spin_lock_irqsave(&sk->sk_receive_queue.lock, flags);
999 head = skb_peek(&sk->sk_receive_queue);
1000 if (likely(head)) {
1001 len = head->len;
1002 if (skb_vlan_tag_present(head))
1003 len += VLAN_HLEN;
1004 }
1005
1006 spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags);
1007 return len;
1008 }
1009
1010 static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk,
1011 bool *busyloop_intr)
1012 {
1013 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX];
1014 struct vhost_net_virtqueue *tnvq = &net->vqs[VHOST_NET_VQ_TX];
1015 struct vhost_virtqueue *rvq = &rnvq->vq;
1016 struct vhost_virtqueue *tvq = &tnvq->vq;
1017 int len = peek_head_len(rnvq, sk);
1018
1019 if (!len && rvq->busyloop_timeout) {
1020 /* Flush batched heads first */
1021 vhost_net_signal_used(rnvq);
1022 /* Both tx vq and rx socket were polled here */
1023 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, true);
1024
1025 len = peek_head_len(rnvq, sk);
1026 }
1027
1028 return len;
1029 }
1030
1031 /* This is a multi-buffer version of vhost_get_desc, that works if
1032 * vq has read descriptors only.
1033 * @vq - the relevant virtqueue
1034 * @datalen - data length we'll be reading
1035 * @iovcount - returned count of io vectors we fill
1036 * @log - vhost log
1037 * @log_num - log offset
1038 * @quota - headcount quota, 1 for big buffer
1039 * returns number of buffer heads allocated, negative on error
1040 */
1041 static int get_rx_bufs(struct vhost_virtqueue *vq,
1042 struct vring_used_elem *heads,
1043 int datalen,
1044 unsigned *iovcount,
1045 struct vhost_log *log,
1046 unsigned *log_num,
1047 unsigned int quota)
1048 {
1049 unsigned int out, in;
1050 int seg = 0;
1051 int headcount = 0;
1052 unsigned d;
1053 int r, nlogs = 0;
1054 /* len is always initialized before use since we are always called with
1055 * datalen > 0.
1056 */
1057 u32 uninitialized_var(len);
1058
1059 while (datalen > 0 && headcount < quota) {
1060 if (unlikely(seg >= UIO_MAXIOV)) {
1061 r = -ENOBUFS;
1062 goto err;
1063 }
1064 r = vhost_get_vq_desc(vq, vq->iov + seg,
1065 ARRAY_SIZE(vq->iov) - seg, &out,
1066 &in, log, log_num);
1067 if (unlikely(r < 0))
1068 goto err;
1069
1070 d = r;
1071 if (d == vq->num) {
1072 r = 0;
1073 goto err;
1074 }
1075 if (unlikely(out || in <= 0)) {
1076 vq_err(vq, "unexpected descriptor format for RX: "
1077 "out %d, in %d\n", out, in);
1078 r = -EINVAL;
1079 goto err;
1080 }
1081 if (unlikely(log)) {
1082 nlogs += *log_num;
1083 log += *log_num;
1084 }
1085 heads[headcount].id = cpu_to_vhost32(vq, d);
1086 len = iov_length(vq->iov + seg, in);
1087 heads[headcount].len = cpu_to_vhost32(vq, len);
1088 datalen -= len;
1089 ++headcount;
1090 seg += in;
1091 }
1092 heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen);
1093 *iovcount = seg;
1094 if (unlikely(log))
1095 *log_num = nlogs;
1096
1097 /* Detect overrun */
1098 if (unlikely(datalen > 0)) {
1099 r = UIO_MAXIOV + 1;
1100 goto err;
1101 }
1102 return headcount;
1103 err:
1104 vhost_discard_vq_desc(vq, headcount);
1105 return r;
1106 }
1107
1108 /* Expects to be always run from workqueue - which acts as
1109 * read-size critical section for our kind of RCU. */
1110 static void handle_rx(struct vhost_net *net)
1111 {
1112 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX];
1113 struct vhost_virtqueue *vq = &nvq->vq;
1114 unsigned uninitialized_var(in), log;
1115 struct vhost_log *vq_log;
1116 struct msghdr msg = {
1117 .msg_name = NULL,
1118 .msg_namelen = 0,
1119 .msg_control = NULL, /* FIXME: get and handle RX aux data. */
1120 .msg_controllen = 0,
1121 .msg_flags = MSG_DONTWAIT,
1122 };
1123 struct virtio_net_hdr hdr = {
1124 .flags = 0,
1125 .gso_type = VIRTIO_NET_HDR_GSO_NONE
1126 };
1127 size_t total_len = 0;
1128 int err, mergeable;
1129 s16 headcount;
1130 size_t vhost_hlen, sock_hlen;
1131 size_t vhost_len, sock_len;
1132 bool busyloop_intr = false;
1133 struct socket *sock;
1134 struct iov_iter fixup;
1135 __virtio16 num_buffers;
1136 int recv_pkts = 0;
1137
1138 mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_RX);
1139 sock = vq->private_data;
1140 if (!sock)
1141 goto out;
1142
1143 if (!vq_iotlb_prefetch(vq))
1144 goto out;
1145
1146 vhost_disable_notify(&net->dev, vq);
1147 vhost_net_disable_vq(net, vq);
1148
1149 vhost_hlen = nvq->vhost_hlen;
1150 sock_hlen = nvq->sock_hlen;
1151
1152 vq_log = unlikely(vhost_has_feature(vq, VHOST_F_LOG_ALL)) ?
1153 vq->log : NULL;
1154 mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF);
1155
1156 while ((sock_len = vhost_net_rx_peek_head_len(net, sock->sk,
1157 &busyloop_intr))) {
1158 sock_len += sock_hlen;
1159 vhost_len = sock_len + vhost_hlen;
1160 headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx,
1161 vhost_len, &in, vq_log, &log,
1162 likely(mergeable) ? UIO_MAXIOV : 1);
1163 /* On error, stop handling until the next kick. */
1164 if (unlikely(headcount < 0))
1165 goto out;
1166 /* OK, now we need to know about added descriptors. */
1167 if (!headcount) {
1168 if (unlikely(busyloop_intr)) {
1169 vhost_poll_queue(&vq->poll);
1170 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) {
1171 /* They have slipped one in as we were
1172 * doing that: check again. */
1173 vhost_disable_notify(&net->dev, vq);
1174 continue;
1175 }
1176 /* Nothing new? Wait for eventfd to tell us
1177 * they refilled. */
1178 goto out;
1179 }
1180 busyloop_intr = false;
1181 if (nvq->rx_ring)
1182 msg.msg_control = vhost_net_buf_consume(&nvq->rxq);
1183 /* On overrun, truncate and discard */
1184 if (unlikely(headcount > UIO_MAXIOV)) {
1185 iov_iter_init(&msg.msg_iter, READ, vq->iov, 1, 1);
1186 err = sock->ops->recvmsg(sock, &msg,
1187 1, MSG_DONTWAIT | MSG_TRUNC);
1188 pr_debug("Discarded rx packet: len %zd\n", sock_len);
1189 continue;
1190 }
1191 /* We don't need to be notified again. */
1192 iov_iter_init(&msg.msg_iter, READ, vq->iov, in, vhost_len);
1193 fixup = msg.msg_iter;
1194 if (unlikely((vhost_hlen))) {
1195 /* We will supply the header ourselves
1196 * TODO: support TSO.
1197 */
1198 iov_iter_advance(&msg.msg_iter, vhost_hlen);
1199 }
1200 err = sock->ops->recvmsg(sock, &msg,
1201 sock_len, MSG_DONTWAIT | MSG_TRUNC);
1202 /* Userspace might have consumed the packet meanwhile:
1203 * it's not supposed to do this usually, but might be hard
1204 * to prevent. Discard data we got (if any) and keep going. */
1205 if (unlikely(err != sock_len)) {
1206 pr_debug("Discarded rx packet: "
1207 " len %d, expected %zd\n", err, sock_len);
1208 vhost_discard_vq_desc(vq, headcount);
1209 continue;
1210 }
1211 /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */
1212 if (unlikely(vhost_hlen)) {
1213 if (copy_to_iter(&hdr, sizeof(hdr),
1214 &fixup) != sizeof(hdr)) {
1215 vq_err(vq, "Unable to write vnet_hdr "
1216 "at addr %p\n", vq->iov->iov_base);
1217 goto out;
1218 }
1219 } else {
1220 /* Header came from socket; we'll need to patch
1221 * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF
1222 */
1223 iov_iter_advance(&fixup, sizeof(hdr));
1224 }
1225 /* TODO: Should check and handle checksum. */
1226
1227 num_buffers = cpu_to_vhost16(vq, headcount);
1228 if (likely(mergeable) &&
1229 copy_to_iter(&num_buffers, sizeof num_buffers,
1230 &fixup) != sizeof num_buffers) {
1231 vq_err(vq, "Failed num_buffers write");
1232 vhost_discard_vq_desc(vq, headcount);
1233 goto out;
1234 }
1235 nvq->done_idx += headcount;
1236 if (nvq->done_idx > VHOST_NET_BATCH)
1237 vhost_net_signal_used(nvq);
1238 if (unlikely(vq_log))
1239 vhost_log_write(vq, vq_log, log, vhost_len,
1240 vq->iov, in);
1241 total_len += vhost_len;
1242 if (unlikely(vhost_exceeds_weight(++recv_pkts, total_len))) {
1243 vhost_poll_queue(&vq->poll);
1244 goto out;
1245 }
1246 }
1247 if (unlikely(busyloop_intr))
1248 vhost_poll_queue(&vq->poll);
1249 else
1250 vhost_net_enable_vq(net, vq);
1251 out:
1252 vhost_net_signal_used(nvq);
1253 mutex_unlock(&vq->mutex);
1254 }
1255
1256 static void handle_tx_kick(struct vhost_work *work)
1257 {
1258 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
1259 poll.work);
1260 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
1261
1262 handle_tx(net);
1263 }
1264
1265 static void handle_rx_kick(struct vhost_work *work)
1266 {
1267 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
1268 poll.work);
1269 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
1270
1271 handle_rx(net);
1272 }
1273
1274 static void handle_tx_net(struct vhost_work *work)
1275 {
1276 struct vhost_net *net = container_of(work, struct vhost_net,
1277 poll[VHOST_NET_VQ_TX].work);
1278 handle_tx(net);
1279 }
1280
1281 static void handle_rx_net(struct vhost_work *work)
1282 {
1283 struct vhost_net *net = container_of(work, struct vhost_net,
1284 poll[VHOST_NET_VQ_RX].work);
1285 handle_rx(net);
1286 }
1287
1288 static int vhost_net_open(struct inode *inode, struct file *f)
1289 {
1290 struct vhost_net *n;
1291 struct vhost_dev *dev;
1292 struct vhost_virtqueue **vqs;
1293 void **queue;
1294 struct xdp_buff *xdp;
1295 int i;
1296
1297 n = kvmalloc(sizeof *n, GFP_KERNEL | __GFP_RETRY_MAYFAIL);
1298 if (!n)
1299 return -ENOMEM;
1300 vqs = kmalloc_array(VHOST_NET_VQ_MAX, sizeof(*vqs), GFP_KERNEL);
1301 if (!vqs) {
1302 kvfree(n);
1303 return -ENOMEM;
1304 }
1305
1306 queue = kmalloc_array(VHOST_NET_BATCH, sizeof(void *),
1307 GFP_KERNEL);
1308 if (!queue) {
1309 kfree(vqs);
1310 kvfree(n);
1311 return -ENOMEM;
1312 }
1313 n->vqs[VHOST_NET_VQ_RX].rxq.queue = queue;
1314
1315 xdp = kmalloc_array(VHOST_NET_BATCH, sizeof(*xdp), GFP_KERNEL);
1316 if (!xdp) {
1317 kfree(vqs);
1318 kvfree(n);
1319 kfree(queue);
1320 return -ENOMEM;
1321 }
1322 n->vqs[VHOST_NET_VQ_TX].xdp = xdp;
1323
1324 dev = &n->dev;
1325 vqs[VHOST_NET_VQ_TX] = &n->vqs[VHOST_NET_VQ_TX].vq;
1326 vqs[VHOST_NET_VQ_RX] = &n->vqs[VHOST_NET_VQ_RX].vq;
1327 n->vqs[VHOST_NET_VQ_TX].vq.handle_kick = handle_tx_kick;
1328 n->vqs[VHOST_NET_VQ_RX].vq.handle_kick = handle_rx_kick;
1329 for (i = 0; i < VHOST_NET_VQ_MAX; i++) {
1330 n->vqs[i].ubufs = NULL;
1331 n->vqs[i].ubuf_info = NULL;
1332 n->vqs[i].upend_idx = 0;
1333 n->vqs[i].done_idx = 0;
1334 n->vqs[i].batched_xdp = 0;
1335 n->vqs[i].vhost_hlen = 0;
1336 n->vqs[i].sock_hlen = 0;
1337 n->vqs[i].rx_ring = NULL;
1338 vhost_net_buf_init(&n->vqs[i].rxq);
1339 }
1340 vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX,
1341 UIO_MAXIOV + VHOST_NET_BATCH);
1342
1343 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, EPOLLOUT, dev);
1344 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, EPOLLIN, dev);
1345
1346 f->private_data = n;
1347 n->page_frag.page = NULL;
1348 n->refcnt_bias = 0;
1349
1350 return 0;
1351 }
1352
1353 static struct socket *vhost_net_stop_vq(struct vhost_net *n,
1354 struct vhost_virtqueue *vq)
1355 {
1356 struct socket *sock;
1357 struct vhost_net_virtqueue *nvq =
1358 container_of(vq, struct vhost_net_virtqueue, vq);
1359
1360 mutex_lock(&vq->mutex);
1361 sock = vq->private_data;
1362 vhost_net_disable_vq(n, vq);
1363 vq->private_data = NULL;
1364 vhost_net_buf_unproduce(nvq);
1365 nvq->rx_ring = NULL;
1366 mutex_unlock(&vq->mutex);
1367 return sock;
1368 }
1369
1370 static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock,
1371 struct socket **rx_sock)
1372 {
1373 *tx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_TX].vq);
1374 *rx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_RX].vq);
1375 }
1376
1377 static void vhost_net_flush_vq(struct vhost_net *n, int index)
1378 {
1379 vhost_poll_flush(n->poll + index);
1380 vhost_poll_flush(&n->vqs[index].vq.poll);
1381 }
1382
1383 static void vhost_net_flush(struct vhost_net *n)
1384 {
1385 vhost_net_flush_vq(n, VHOST_NET_VQ_TX);
1386 vhost_net_flush_vq(n, VHOST_NET_VQ_RX);
1387 if (n->vqs[VHOST_NET_VQ_TX].ubufs) {
1388 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1389 n->tx_flush = true;
1390 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1391 /* Wait for all lower device DMAs done. */
1392 vhost_net_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs);
1393 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1394 n->tx_flush = false;
1395 atomic_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1);
1396 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1397 }
1398 }
1399
1400 static int vhost_net_release(struct inode *inode, struct file *f)
1401 {
1402 struct vhost_net *n = f->private_data;
1403 struct socket *tx_sock;
1404 struct socket *rx_sock;
1405
1406 vhost_net_stop(n, &tx_sock, &rx_sock);
1407 vhost_net_flush(n);
1408 vhost_dev_stop(&n->dev);
1409 vhost_dev_cleanup(&n->dev);
1410 vhost_net_vq_reset(n);
1411 if (tx_sock)
1412 sockfd_put(tx_sock);
1413 if (rx_sock)
1414 sockfd_put(rx_sock);
1415 /* Make sure no callbacks are outstanding */
1416 synchronize_rcu();
1417 /* We do an extra flush before freeing memory,
1418 * since jobs can re-queue themselves. */
1419 vhost_net_flush(n);
1420 kfree(n->vqs[VHOST_NET_VQ_RX].rxq.queue);
1421 kfree(n->vqs[VHOST_NET_VQ_TX].xdp);
1422 kfree(n->dev.vqs);
1423 if (n->page_frag.page)
1424 __page_frag_cache_drain(n->page_frag.page, n->refcnt_bias);
1425 kvfree(n);
1426 return 0;
1427 }
1428
1429 static struct socket *get_raw_socket(int fd)
1430 {
1431 struct {
1432 struct sockaddr_ll sa;
1433 char buf[MAX_ADDR_LEN];
1434 } uaddr;
1435 int r;
1436 struct socket *sock = sockfd_lookup(fd, &r);
1437
1438 if (!sock)
1439 return ERR_PTR(-ENOTSOCK);
1440
1441 /* Parameter checking */
1442 if (sock->sk->sk_type != SOCK_RAW) {
1443 r = -ESOCKTNOSUPPORT;
1444 goto err;
1445 }
1446
1447 r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa, 0);
1448 if (r < 0)
1449 goto err;
1450
1451 if (uaddr.sa.sll_family != AF_PACKET) {
1452 r = -EPFNOSUPPORT;
1453 goto err;
1454 }
1455 return sock;
1456 err:
1457 sockfd_put(sock);
1458 return ERR_PTR(r);
1459 }
1460
1461 static struct ptr_ring *get_tap_ptr_ring(int fd)
1462 {
1463 struct ptr_ring *ring;
1464 struct file *file = fget(fd);
1465
1466 if (!file)
1467 return NULL;
1468 ring = tun_get_tx_ring(file);
1469 if (!IS_ERR(ring))
1470 goto out;
1471 ring = tap_get_ptr_ring(file);
1472 if (!IS_ERR(ring))
1473 goto out;
1474 ring = NULL;
1475 out:
1476 fput(file);
1477 return ring;
1478 }
1479
1480 static struct socket *get_tap_socket(int fd)
1481 {
1482 struct file *file = fget(fd);
1483 struct socket *sock;
1484
1485 if (!file)
1486 return ERR_PTR(-EBADF);
1487 sock = tun_get_socket(file);
1488 if (!IS_ERR(sock))
1489 return sock;
1490 sock = tap_get_socket(file);
1491 if (IS_ERR(sock))
1492 fput(file);
1493 return sock;
1494 }
1495
1496 static struct socket *get_socket(int fd)
1497 {
1498 struct socket *sock;
1499
1500 /* special case to disable backend */
1501 if (fd == -1)
1502 return NULL;
1503 sock = get_raw_socket(fd);
1504 if (!IS_ERR(sock))
1505 return sock;
1506 sock = get_tap_socket(fd);
1507 if (!IS_ERR(sock))
1508 return sock;
1509 return ERR_PTR(-ENOTSOCK);
1510 }
1511
1512 static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
1513 {
1514 struct socket *sock, *oldsock;
1515 struct vhost_virtqueue *vq;
1516 struct vhost_net_virtqueue *nvq;
1517 struct vhost_net_ubuf_ref *ubufs, *oldubufs = NULL;
1518 int r;
1519
1520 mutex_lock(&n->dev.mutex);
1521 r = vhost_dev_check_owner(&n->dev);
1522 if (r)
1523 goto err;
1524
1525 if (index >= VHOST_NET_VQ_MAX) {
1526 r = -ENOBUFS;
1527 goto err;
1528 }
1529 vq = &n->vqs[index].vq;
1530 nvq = &n->vqs[index];
1531 mutex_lock(&vq->mutex);
1532
1533 /* Verify that ring has been setup correctly. */
1534 if (!vhost_vq_access_ok(vq)) {
1535 r = -EFAULT;
1536 goto err_vq;
1537 }
1538 sock = get_socket(fd);
1539 if (IS_ERR(sock)) {
1540 r = PTR_ERR(sock);
1541 goto err_vq;
1542 }
1543
1544 /* start polling new socket */
1545 oldsock = vq->private_data;
1546 if (sock != oldsock) {
1547 ubufs = vhost_net_ubuf_alloc(vq,
1548 sock && vhost_sock_zcopy(sock));
1549 if (IS_ERR(ubufs)) {
1550 r = PTR_ERR(ubufs);
1551 goto err_ubufs;
1552 }
1553
1554 vhost_net_disable_vq(n, vq);
1555 vq->private_data = sock;
1556 vhost_net_buf_unproduce(nvq);
1557 r = vhost_vq_init_access(vq);
1558 if (r)
1559 goto err_used;
1560 r = vhost_net_enable_vq(n, vq);
1561 if (r)
1562 goto err_used;
1563 if (index == VHOST_NET_VQ_RX)
1564 nvq->rx_ring = get_tap_ptr_ring(fd);
1565
1566 oldubufs = nvq->ubufs;
1567 nvq->ubufs = ubufs;
1568
1569 n->tx_packets = 0;
1570 n->tx_zcopy_err = 0;
1571 n->tx_flush = false;
1572 }
1573
1574 mutex_unlock(&vq->mutex);
1575
1576 if (oldubufs) {
1577 vhost_net_ubuf_put_wait_and_free(oldubufs);
1578 mutex_lock(&vq->mutex);
1579 vhost_zerocopy_signal_used(n, vq);
1580 mutex_unlock(&vq->mutex);
1581 }
1582
1583 if (oldsock) {
1584 vhost_net_flush_vq(n, index);
1585 sockfd_put(oldsock);
1586 }
1587
1588 mutex_unlock(&n->dev.mutex);
1589 return 0;
1590
1591 err_used:
1592 vq->private_data = oldsock;
1593 vhost_net_enable_vq(n, vq);
1594 if (ubufs)
1595 vhost_net_ubuf_put_wait_and_free(ubufs);
1596 err_ubufs:
1597 if (sock)
1598 sockfd_put(sock);
1599 err_vq:
1600 mutex_unlock(&vq->mutex);
1601 err:
1602 mutex_unlock(&n->dev.mutex);
1603 return r;
1604 }
1605
1606 static long vhost_net_reset_owner(struct vhost_net *n)
1607 {
1608 struct socket *tx_sock = NULL;
1609 struct socket *rx_sock = NULL;
1610 long err;
1611 struct vhost_umem *umem;
1612
1613 mutex_lock(&n->dev.mutex);
1614 err = vhost_dev_check_owner(&n->dev);
1615 if (err)
1616 goto done;
1617 umem = vhost_dev_reset_owner_prepare();
1618 if (!umem) {
1619 err = -ENOMEM;
1620 goto done;
1621 }
1622 vhost_net_stop(n, &tx_sock, &rx_sock);
1623 vhost_net_flush(n);
1624 vhost_dev_stop(&n->dev);
1625 vhost_dev_reset_owner(&n->dev, umem);
1626 vhost_net_vq_reset(n);
1627 done:
1628 mutex_unlock(&n->dev.mutex);
1629 if (tx_sock)
1630 sockfd_put(tx_sock);
1631 if (rx_sock)
1632 sockfd_put(rx_sock);
1633 return err;
1634 }
1635
1636 static int vhost_net_set_backend_features(struct vhost_net *n, u64 features)
1637 {
1638 int i;
1639
1640 mutex_lock(&n->dev.mutex);
1641 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
1642 mutex_lock(&n->vqs[i].vq.mutex);
1643 n->vqs[i].vq.acked_backend_features = features;
1644 mutex_unlock(&n->vqs[i].vq.mutex);
1645 }
1646 mutex_unlock(&n->dev.mutex);
1647
1648 return 0;
1649 }
1650
1651 static int vhost_net_set_features(struct vhost_net *n, u64 features)
1652 {
1653 size_t vhost_hlen, sock_hlen, hdr_len;
1654 int i;
1655
1656 hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) |
1657 (1ULL << VIRTIO_F_VERSION_1))) ?
1658 sizeof(struct virtio_net_hdr_mrg_rxbuf) :
1659 sizeof(struct virtio_net_hdr);
1660 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) {
1661 /* vhost provides vnet_hdr */
1662 vhost_hlen = hdr_len;
1663 sock_hlen = 0;
1664 } else {
1665 /* socket provides vnet_hdr */
1666 vhost_hlen = 0;
1667 sock_hlen = hdr_len;
1668 }
1669 mutex_lock(&n->dev.mutex);
1670 if ((features & (1 << VHOST_F_LOG_ALL)) &&
1671 !vhost_log_access_ok(&n->dev))
1672 goto out_unlock;
1673
1674 if ((features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))) {
1675 if (vhost_init_device_iotlb(&n->dev, true))
1676 goto out_unlock;
1677 }
1678
1679 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
1680 mutex_lock(&n->vqs[i].vq.mutex);
1681 n->vqs[i].vq.acked_features = features;
1682 n->vqs[i].vhost_hlen = vhost_hlen;
1683 n->vqs[i].sock_hlen = sock_hlen;
1684 mutex_unlock(&n->vqs[i].vq.mutex);
1685 }
1686 mutex_unlock(&n->dev.mutex);
1687 return 0;
1688
1689 out_unlock:
1690 mutex_unlock(&n->dev.mutex);
1691 return -EFAULT;
1692 }
1693
1694 static long vhost_net_set_owner(struct vhost_net *n)
1695 {
1696 int r;
1697
1698 mutex_lock(&n->dev.mutex);
1699 if (vhost_dev_has_owner(&n->dev)) {
1700 r = -EBUSY;
1701 goto out;
1702 }
1703 r = vhost_net_set_ubuf_info(n);
1704 if (r)
1705 goto out;
1706 r = vhost_dev_set_owner(&n->dev);
1707 if (r)
1708 vhost_net_clear_ubuf_info(n);
1709 vhost_net_flush(n);
1710 out:
1711 mutex_unlock(&n->dev.mutex);
1712 return r;
1713 }
1714
1715 static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
1716 unsigned long arg)
1717 {
1718 struct vhost_net *n = f->private_data;
1719 void __user *argp = (void __user *)arg;
1720 u64 __user *featurep = argp;
1721 struct vhost_vring_file backend;
1722 u64 features;
1723 int r;
1724
1725 switch (ioctl) {
1726 case VHOST_NET_SET_BACKEND:
1727 if (copy_from_user(&backend, argp, sizeof backend))
1728 return -EFAULT;
1729 return vhost_net_set_backend(n, backend.index, backend.fd);
1730 case VHOST_GET_FEATURES:
1731 features = VHOST_NET_FEATURES;
1732 if (copy_to_user(featurep, &features, sizeof features))
1733 return -EFAULT;
1734 return 0;
1735 case VHOST_SET_FEATURES:
1736 if (copy_from_user(&features, featurep, sizeof features))
1737 return -EFAULT;
1738 if (features & ~VHOST_NET_FEATURES)
1739 return -EOPNOTSUPP;
1740 return vhost_net_set_features(n, features);
1741 case VHOST_GET_BACKEND_FEATURES:
1742 features = VHOST_NET_BACKEND_FEATURES;
1743 if (copy_to_user(featurep, &features, sizeof(features)))
1744 return -EFAULT;
1745 return 0;
1746 case VHOST_SET_BACKEND_FEATURES:
1747 if (copy_from_user(&features, featurep, sizeof(features)))
1748 return -EFAULT;
1749 if (features & ~VHOST_NET_BACKEND_FEATURES)
1750 return -EOPNOTSUPP;
1751 return vhost_net_set_backend_features(n, features);
1752 case VHOST_RESET_OWNER:
1753 return vhost_net_reset_owner(n);
1754 case VHOST_SET_OWNER:
1755 return vhost_net_set_owner(n);
1756 default:
1757 mutex_lock(&n->dev.mutex);
1758 r = vhost_dev_ioctl(&n->dev, ioctl, argp);
1759 if (r == -ENOIOCTLCMD)
1760 r = vhost_vring_ioctl(&n->dev, ioctl, argp);
1761 else
1762 vhost_net_flush(n);
1763 mutex_unlock(&n->dev.mutex);
1764 return r;
1765 }
1766 }
1767
1768 #ifdef CONFIG_COMPAT
1769 static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl,
1770 unsigned long arg)
1771 {
1772 return vhost_net_ioctl(f, ioctl, (unsigned long)compat_ptr(arg));
1773 }
1774 #endif
1775
1776 static ssize_t vhost_net_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1777 {
1778 struct file *file = iocb->ki_filp;
1779 struct vhost_net *n = file->private_data;
1780 struct vhost_dev *dev = &n->dev;
1781 int noblock = file->f_flags & O_NONBLOCK;
1782
1783 return vhost_chr_read_iter(dev, to, noblock);
1784 }
1785
1786 static ssize_t vhost_net_chr_write_iter(struct kiocb *iocb,
1787 struct iov_iter *from)
1788 {
1789 struct file *file = iocb->ki_filp;
1790 struct vhost_net *n = file->private_data;
1791 struct vhost_dev *dev = &n->dev;
1792
1793 return vhost_chr_write_iter(dev, from);
1794 }
1795
1796 static __poll_t vhost_net_chr_poll(struct file *file, poll_table *wait)
1797 {
1798 struct vhost_net *n = file->private_data;
1799 struct vhost_dev *dev = &n->dev;
1800
1801 return vhost_chr_poll(file, dev, wait);
1802 }
1803
1804 static const struct file_operations vhost_net_fops = {
1805 .owner = THIS_MODULE,
1806 .release = vhost_net_release,
1807 .read_iter = vhost_net_chr_read_iter,
1808 .write_iter = vhost_net_chr_write_iter,
1809 .poll = vhost_net_chr_poll,
1810 .unlocked_ioctl = vhost_net_ioctl,
1811 #ifdef CONFIG_COMPAT
1812 .compat_ioctl = vhost_net_compat_ioctl,
1813 #endif
1814 .open = vhost_net_open,
1815 .llseek = noop_llseek,
1816 };
1817
1818 static struct miscdevice vhost_net_misc = {
1819 .minor = VHOST_NET_MINOR,
1820 .name = "vhost-net",
1821 .fops = &vhost_net_fops,
1822 };
1823
1824 static int vhost_net_init(void)
1825 {
1826 if (experimental_zcopytx)
1827 vhost_net_enable_zcopy(VHOST_NET_VQ_TX);
1828 return misc_register(&vhost_net_misc);
1829 }
1830 module_init(vhost_net_init);
1831
1832 static void vhost_net_exit(void)
1833 {
1834 misc_deregister(&vhost_net_misc);
1835 }
1836 module_exit(vhost_net_exit);
1837
1838 MODULE_VERSION("0.0.1");
1839 MODULE_LICENSE("GPL v2");
1840 MODULE_AUTHOR("Michael S. Tsirkin");
1841 MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
1842 MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR);
1843 MODULE_ALIAS("devname:vhost-net");
Linux with added FPC-III support