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