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