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Merge tag 'pm-6.16-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
[linux-2.6-block.git] / drivers / vhost / net.c
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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 (1ULL << VIRTIO_F_RING_RESET)
78};
79
80enum {
81 VHOST_NET_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2)
82};
83
84enum {
85 VHOST_NET_VQ_RX = 0,
86 VHOST_NET_VQ_TX = 1,
87 VHOST_NET_VQ_MAX = 2,
88};
89
90struct vhost_net_ubuf_ref {
91 /* refcount follows semantics similar to kref:
92 * 0: object is released
93 * 1: no outstanding ubufs
94 * >1: outstanding ubufs
95 */
96 atomic_t refcount;
97 wait_queue_head_t wait;
98 struct vhost_virtqueue *vq;
99};
100
101#define VHOST_NET_BATCH 64
102struct vhost_net_buf {
103 void **queue;
104 int tail;
105 int head;
106};
107
108struct vhost_net_virtqueue {
109 struct vhost_virtqueue vq;
110 size_t vhost_hlen;
111 size_t sock_hlen;
112 /* vhost zerocopy support fields below: */
113 /* last used idx for outstanding DMA zerocopy buffers */
114 int upend_idx;
115 /* For TX, first used idx for DMA done zerocopy buffers
116 * For RX, number of batched heads
117 */
118 int done_idx;
119 /* Number of XDP frames batched */
120 int batched_xdp;
121 /* an array of userspace buffers info */
122 struct ubuf_info_msgzc *ubuf_info;
123 /* Reference counting for outstanding ubufs.
124 * Protected by vq mutex. Writers must also take device mutex. */
125 struct vhost_net_ubuf_ref *ubufs;
126 struct ptr_ring *rx_ring;
127 struct vhost_net_buf rxq;
128 /* Batched XDP buffs */
129 struct xdp_buff *xdp;
130};
131
132struct vhost_net {
133 struct vhost_dev dev;
134 struct vhost_net_virtqueue vqs[VHOST_NET_VQ_MAX];
135 struct vhost_poll poll[VHOST_NET_VQ_MAX];
136 /* Number of TX recently submitted.
137 * Protected by tx vq lock. */
138 unsigned tx_packets;
139 /* Number of times zerocopy TX recently failed.
140 * Protected by tx vq lock. */
141 unsigned tx_zcopy_err;
142 /* Flush in progress. Protected by tx vq lock. */
143 bool tx_flush;
144 /* Private page frag cache */
145 struct page_frag_cache pf_cache;
146};
147
148static unsigned vhost_net_zcopy_mask __read_mostly;
149
150static void *vhost_net_buf_get_ptr(struct vhost_net_buf *rxq)
151{
152 if (rxq->tail != rxq->head)
153 return rxq->queue[rxq->head];
154 else
155 return NULL;
156}
157
158static int vhost_net_buf_get_size(struct vhost_net_buf *rxq)
159{
160 return rxq->tail - rxq->head;
161}
162
163static int vhost_net_buf_is_empty(struct vhost_net_buf *rxq)
164{
165 return rxq->tail == rxq->head;
166}
167
168static void *vhost_net_buf_consume(struct vhost_net_buf *rxq)
169{
170 void *ret = vhost_net_buf_get_ptr(rxq);
171 ++rxq->head;
172 return ret;
173}
174
175static int vhost_net_buf_produce(struct vhost_net_virtqueue *nvq)
176{
177 struct vhost_net_buf *rxq = &nvq->rxq;
178
179 rxq->head = 0;
180 rxq->tail = ptr_ring_consume_batched(nvq->rx_ring, rxq->queue,
181 VHOST_NET_BATCH);
182 return rxq->tail;
183}
184
185static void vhost_net_buf_unproduce(struct vhost_net_virtqueue *nvq)
186{
187 struct vhost_net_buf *rxq = &nvq->rxq;
188
189 if (nvq->rx_ring && !vhost_net_buf_is_empty(rxq)) {
190 ptr_ring_unconsume(nvq->rx_ring, rxq->queue + rxq->head,
191 vhost_net_buf_get_size(rxq),
192 tun_ptr_free);
193 rxq->head = rxq->tail = 0;
194 }
195}
196
197static int vhost_net_buf_peek_len(void *ptr)
198{
199 if (tun_is_xdp_frame(ptr)) {
200 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr);
201
202 return xdpf->len;
203 }
204
205 return __skb_array_len_with_tag(ptr);
206}
207
208static int vhost_net_buf_peek(struct vhost_net_virtqueue *nvq)
209{
210 struct vhost_net_buf *rxq = &nvq->rxq;
211
212 if (!vhost_net_buf_is_empty(rxq))
213 goto out;
214
215 if (!vhost_net_buf_produce(nvq))
216 return 0;
217
218out:
219 return vhost_net_buf_peek_len(vhost_net_buf_get_ptr(rxq));
220}
221
222static void vhost_net_buf_init(struct vhost_net_buf *rxq)
223{
224 rxq->head = rxq->tail = 0;
225}
226
227static void vhost_net_enable_zcopy(int vq)
228{
229 vhost_net_zcopy_mask |= 0x1 << vq;
230}
231
232static struct vhost_net_ubuf_ref *
233vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy)
234{
235 struct vhost_net_ubuf_ref *ubufs;
236 /* No zero copy backend? Nothing to count. */
237 if (!zcopy)
238 return NULL;
239 ubufs = kmalloc(sizeof(*ubufs), GFP_KERNEL);
240 if (!ubufs)
241 return ERR_PTR(-ENOMEM);
242 atomic_set(&ubufs->refcount, 1);
243 init_waitqueue_head(&ubufs->wait);
244 ubufs->vq = vq;
245 return ubufs;
246}
247
248static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs)
249{
250 int r = atomic_sub_return(1, &ubufs->refcount);
251 if (unlikely(!r))
252 wake_up(&ubufs->wait);
253 return r;
254}
255
256static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs)
257{
258 vhost_net_ubuf_put(ubufs);
259 wait_event(ubufs->wait, !atomic_read(&ubufs->refcount));
260}
261
262static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs)
263{
264 vhost_net_ubuf_put_and_wait(ubufs);
265 kfree(ubufs);
266}
267
268static void vhost_net_clear_ubuf_info(struct vhost_net *n)
269{
270 int i;
271
272 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
273 kfree(n->vqs[i].ubuf_info);
274 n->vqs[i].ubuf_info = NULL;
275 }
276}
277
278static int vhost_net_set_ubuf_info(struct vhost_net *n)
279{
280 bool zcopy;
281 int i;
282
283 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
284 zcopy = vhost_net_zcopy_mask & (0x1 << i);
285 if (!zcopy)
286 continue;
287 n->vqs[i].ubuf_info =
288 kmalloc_array(UIO_MAXIOV,
289 sizeof(*n->vqs[i].ubuf_info),
290 GFP_KERNEL);
291 if (!n->vqs[i].ubuf_info)
292 goto err;
293 }
294 return 0;
295
296err:
297 vhost_net_clear_ubuf_info(n);
298 return -ENOMEM;
299}
300
301static void vhost_net_vq_reset(struct vhost_net *n)
302{
303 int i;
304
305 vhost_net_clear_ubuf_info(n);
306
307 for (i = 0; i < VHOST_NET_VQ_MAX; i++) {
308 n->vqs[i].done_idx = 0;
309 n->vqs[i].upend_idx = 0;
310 n->vqs[i].ubufs = NULL;
311 n->vqs[i].vhost_hlen = 0;
312 n->vqs[i].sock_hlen = 0;
313 vhost_net_buf_init(&n->vqs[i].rxq);
314 }
315
316}
317
318static void vhost_net_tx_packet(struct vhost_net *net)
319{
320 ++net->tx_packets;
321 if (net->tx_packets < 1024)
322 return;
323 net->tx_packets = 0;
324 net->tx_zcopy_err = 0;
325}
326
327static void vhost_net_tx_err(struct vhost_net *net)
328{
329 ++net->tx_zcopy_err;
330}
331
332static bool vhost_net_tx_select_zcopy(struct vhost_net *net)
333{
334 /* TX flush waits for outstanding DMAs to be done.
335 * Don't start new DMAs.
336 */
337 return !net->tx_flush &&
338 net->tx_packets / 64 >= net->tx_zcopy_err;
339}
340
341static bool vhost_sock_zcopy(struct socket *sock)
342{
343 return unlikely(experimental_zcopytx) &&
344 sock_flag(sock->sk, SOCK_ZEROCOPY);
345}
346
347static bool vhost_sock_xdp(struct socket *sock)
348{
349 return sock_flag(sock->sk, SOCK_XDP);
350}
351
352/* In case of DMA done not in order in lower device driver for some reason.
353 * upend_idx is used to track end of used idx, done_idx is used to track head
354 * of used idx. Once lower device DMA done contiguously, we will signal KVM
355 * guest used idx.
356 */
357static void vhost_zerocopy_signal_used(struct vhost_net *net,
358 struct vhost_virtqueue *vq)
359{
360 struct vhost_net_virtqueue *nvq =
361 container_of(vq, struct vhost_net_virtqueue, vq);
362 int i, add;
363 int j = 0;
364
365 for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) {
366 if (vq->heads[i].len == VHOST_DMA_FAILED_LEN)
367 vhost_net_tx_err(net);
368 if (VHOST_DMA_IS_DONE(vq->heads[i].len)) {
369 vq->heads[i].len = VHOST_DMA_CLEAR_LEN;
370 ++j;
371 } else
372 break;
373 }
374 while (j) {
375 add = min(UIO_MAXIOV - nvq->done_idx, j);
376 vhost_add_used_and_signal_n(vq->dev, vq,
377 &vq->heads[nvq->done_idx], add);
378 nvq->done_idx = (nvq->done_idx + add) % UIO_MAXIOV;
379 j -= add;
380 }
381}
382
383static void vhost_zerocopy_complete(struct sk_buff *skb,
384 struct ubuf_info *ubuf_base, bool success)
385{
386 struct ubuf_info_msgzc *ubuf = uarg_to_msgzc(ubuf_base);
387 struct vhost_net_ubuf_ref *ubufs = ubuf->ctx;
388 struct vhost_virtqueue *vq = ubufs->vq;
389 int cnt;
390
391 rcu_read_lock_bh();
392
393 /* set len to mark this desc buffers done DMA */
394 vq->heads[ubuf->desc].len = success ?
395 VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN;
396 cnt = vhost_net_ubuf_put(ubufs);
397
398 /*
399 * Trigger polling thread if guest stopped submitting new buffers:
400 * in this case, the refcount after decrement will eventually reach 1.
401 * We also trigger polling periodically after each 16 packets
402 * (the value 16 here is more or less arbitrary, it's tuned to trigger
403 * less than 10% of times).
404 */
405 if (cnt <= 1 || !(cnt % 16))
406 vhost_poll_queue(&vq->poll);
407
408 rcu_read_unlock_bh();
409}
410
411static const struct ubuf_info_ops vhost_ubuf_ops = {
412 .complete = vhost_zerocopy_complete,
413};
414
415static inline unsigned long busy_clock(void)
416{
417 return local_clock() >> 10;
418}
419
420static bool vhost_can_busy_poll(unsigned long endtime)
421{
422 return likely(!need_resched() && !time_after(busy_clock(), endtime) &&
423 !signal_pending(current));
424}
425
426static void vhost_net_disable_vq(struct vhost_net *n,
427 struct vhost_virtqueue *vq)
428{
429 struct vhost_net_virtqueue *nvq =
430 container_of(vq, struct vhost_net_virtqueue, vq);
431 struct vhost_poll *poll = n->poll + (nvq - n->vqs);
432 if (!vhost_vq_get_backend(vq))
433 return;
434 vhost_poll_stop(poll);
435}
436
437static int vhost_net_enable_vq(struct vhost_net *n,
438 struct vhost_virtqueue *vq)
439{
440 struct vhost_net_virtqueue *nvq =
441 container_of(vq, struct vhost_net_virtqueue, vq);
442 struct vhost_poll *poll = n->poll + (nvq - n->vqs);
443 struct socket *sock;
444
445 sock = vhost_vq_get_backend(vq);
446 if (!sock)
447 return 0;
448
449 return vhost_poll_start(poll, sock->file);
450}
451
452static void vhost_net_signal_used(struct vhost_net_virtqueue *nvq)
453{
454 struct vhost_virtqueue *vq = &nvq->vq;
455 struct vhost_dev *dev = vq->dev;
456
457 if (!nvq->done_idx)
458 return;
459
460 vhost_add_used_and_signal_n(dev, vq, vq->heads, nvq->done_idx);
461 nvq->done_idx = 0;
462}
463
464static void vhost_tx_batch(struct vhost_net *net,
465 struct vhost_net_virtqueue *nvq,
466 struct socket *sock,
467 struct msghdr *msghdr)
468{
469 struct tun_msg_ctl ctl = {
470 .type = TUN_MSG_PTR,
471 .num = nvq->batched_xdp,
472 .ptr = nvq->xdp,
473 };
474 int i, err;
475
476 if (nvq->batched_xdp == 0)
477 goto signal_used;
478
479 msghdr->msg_control = &ctl;
480 msghdr->msg_controllen = sizeof(ctl);
481 err = sock->ops->sendmsg(sock, msghdr, 0);
482 if (unlikely(err < 0)) {
483 vq_err(&nvq->vq, "Fail to batch sending packets\n");
484
485 /* free pages owned by XDP; since this is an unlikely error path,
486 * keep it simple and avoid more complex bulk update for the
487 * used pages
488 */
489 for (i = 0; i < nvq->batched_xdp; ++i)
490 put_page(virt_to_head_page(nvq->xdp[i].data));
491 nvq->batched_xdp = 0;
492 nvq->done_idx = 0;
493 return;
494 }
495
496signal_used:
497 vhost_net_signal_used(nvq);
498 nvq->batched_xdp = 0;
499}
500
501static int sock_has_rx_data(struct socket *sock)
502{
503 if (unlikely(!sock))
504 return 0;
505
506 if (sock->ops->peek_len)
507 return sock->ops->peek_len(sock);
508
509 return skb_queue_empty(&sock->sk->sk_receive_queue);
510}
511
512static void vhost_net_busy_poll_try_queue(struct vhost_net *net,
513 struct vhost_virtqueue *vq)
514{
515 if (!vhost_vq_avail_empty(&net->dev, vq)) {
516 vhost_poll_queue(&vq->poll);
517 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) {
518 vhost_disable_notify(&net->dev, vq);
519 vhost_poll_queue(&vq->poll);
520 }
521}
522
523static void vhost_net_busy_poll(struct vhost_net *net,
524 struct vhost_virtqueue *rvq,
525 struct vhost_virtqueue *tvq,
526 bool *busyloop_intr,
527 bool poll_rx)
528{
529 unsigned long busyloop_timeout;
530 unsigned long endtime;
531 struct socket *sock;
532 struct vhost_virtqueue *vq = poll_rx ? tvq : rvq;
533
534 /* Try to hold the vq mutex of the paired virtqueue. We can't
535 * use mutex_lock() here since we could not guarantee a
536 * consistenet lock ordering.
537 */
538 if (!mutex_trylock(&vq->mutex))
539 return;
540
541 vhost_disable_notify(&net->dev, vq);
542 sock = vhost_vq_get_backend(rvq);
543
544 busyloop_timeout = poll_rx ? rvq->busyloop_timeout:
545 tvq->busyloop_timeout;
546
547 preempt_disable();
548 endtime = busy_clock() + busyloop_timeout;
549
550 while (vhost_can_busy_poll(endtime)) {
551 if (vhost_vq_has_work(vq)) {
552 *busyloop_intr = true;
553 break;
554 }
555
556 if ((sock_has_rx_data(sock) &&
557 !vhost_vq_avail_empty(&net->dev, rvq)) ||
558 !vhost_vq_avail_empty(&net->dev, tvq))
559 break;
560
561 cpu_relax();
562 }
563
564 preempt_enable();
565
566 if (poll_rx || sock_has_rx_data(sock))
567 vhost_net_busy_poll_try_queue(net, vq);
568 else if (!poll_rx) /* On tx here, sock has no rx data. */
569 vhost_enable_notify(&net->dev, rvq);
570
571 mutex_unlock(&vq->mutex);
572}
573
574static int vhost_net_tx_get_vq_desc(struct vhost_net *net,
575 struct vhost_net_virtqueue *tnvq,
576 unsigned int *out_num, unsigned int *in_num,
577 struct msghdr *msghdr, bool *busyloop_intr)
578{
579 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX];
580 struct vhost_virtqueue *rvq = &rnvq->vq;
581 struct vhost_virtqueue *tvq = &tnvq->vq;
582
583 int r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov),
584 out_num, in_num, NULL, NULL);
585
586 if (r == tvq->num && tvq->busyloop_timeout) {
587 /* Flush batched packets first */
588 if (!vhost_sock_zcopy(vhost_vq_get_backend(tvq)))
589 vhost_tx_batch(net, tnvq,
590 vhost_vq_get_backend(tvq),
591 msghdr);
592
593 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, false);
594
595 r = vhost_get_vq_desc(tvq, tvq->iov, ARRAY_SIZE(tvq->iov),
596 out_num, in_num, NULL, NULL);
597 }
598
599 return r;
600}
601
602static bool vhost_exceeds_maxpend(struct vhost_net *net)
603{
604 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
605 struct vhost_virtqueue *vq = &nvq->vq;
606
607 return (nvq->upend_idx + UIO_MAXIOV - nvq->done_idx) % UIO_MAXIOV >
608 min_t(unsigned int, VHOST_MAX_PEND, vq->num >> 2);
609}
610
611static size_t init_iov_iter(struct vhost_virtqueue *vq, struct iov_iter *iter,
612 size_t hdr_size, int out)
613{
614 /* Skip header. TODO: support TSO. */
615 size_t len = iov_length(vq->iov, out);
616
617 iov_iter_init(iter, ITER_SOURCE, vq->iov, out, len);
618 iov_iter_advance(iter, hdr_size);
619
620 return iov_iter_count(iter);
621}
622
623static int get_tx_bufs(struct vhost_net *net,
624 struct vhost_net_virtqueue *nvq,
625 struct msghdr *msg,
626 unsigned int *out, unsigned int *in,
627 size_t *len, bool *busyloop_intr)
628{
629 struct vhost_virtqueue *vq = &nvq->vq;
630 int ret;
631
632 ret = vhost_net_tx_get_vq_desc(net, nvq, out, in, msg, busyloop_intr);
633
634 if (ret < 0 || ret == vq->num)
635 return ret;
636
637 if (*in) {
638 vq_err(vq, "Unexpected descriptor format for TX: out %d, int %d\n",
639 *out, *in);
640 return -EFAULT;
641 }
642
643 /* Sanity check */
644 *len = init_iov_iter(vq, &msg->msg_iter, nvq->vhost_hlen, *out);
645 if (*len == 0) {
646 vq_err(vq, "Unexpected header len for TX: %zd expected %zd\n",
647 *len, nvq->vhost_hlen);
648 return -EFAULT;
649 }
650
651 return ret;
652}
653
654static bool tx_can_batch(struct vhost_virtqueue *vq, size_t total_len)
655{
656 return total_len < VHOST_NET_WEIGHT &&
657 !vhost_vq_avail_empty(vq->dev, vq);
658}
659
660#define VHOST_NET_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
661
662static int vhost_net_build_xdp(struct vhost_net_virtqueue *nvq,
663 struct iov_iter *from)
664{
665 struct vhost_virtqueue *vq = &nvq->vq;
666 struct vhost_net *net = container_of(vq->dev, struct vhost_net,
667 dev);
668 struct socket *sock = vhost_vq_get_backend(vq);
669 struct virtio_net_hdr *gso;
670 struct xdp_buff *xdp = &nvq->xdp[nvq->batched_xdp];
671 struct tun_xdp_hdr *hdr;
672 size_t len = iov_iter_count(from);
673 int headroom = vhost_sock_xdp(sock) ? XDP_PACKET_HEADROOM : 0;
674 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info));
675 int pad = SKB_DATA_ALIGN(VHOST_NET_RX_PAD + headroom + nvq->sock_hlen);
676 int sock_hlen = nvq->sock_hlen;
677 void *buf;
678 int copied;
679 int ret;
680
681 if (unlikely(len < nvq->sock_hlen))
682 return -EFAULT;
683
684 if (SKB_DATA_ALIGN(len + pad) +
685 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE)
686 return -ENOSPC;
687
688 buflen += SKB_DATA_ALIGN(len + pad);
689 buf = page_frag_alloc_align(&net->pf_cache, buflen, GFP_KERNEL,
690 SMP_CACHE_BYTES);
691 if (unlikely(!buf))
692 return -ENOMEM;
693
694 copied = copy_from_iter(buf + offsetof(struct tun_xdp_hdr, gso),
695 sock_hlen, from);
696 if (copied != sock_hlen) {
697 ret = -EFAULT;
698 goto err;
699 }
700
701 hdr = buf;
702 gso = &hdr->gso;
703
704 if (!sock_hlen)
705 memset(buf, 0, pad);
706
707 if ((gso->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) &&
708 vhost16_to_cpu(vq, gso->csum_start) +
709 vhost16_to_cpu(vq, gso->csum_offset) + 2 >
710 vhost16_to_cpu(vq, gso->hdr_len)) {
711 gso->hdr_len = cpu_to_vhost16(vq,
712 vhost16_to_cpu(vq, gso->csum_start) +
713 vhost16_to_cpu(vq, gso->csum_offset) + 2);
714
715 if (vhost16_to_cpu(vq, gso->hdr_len) > len) {
716 ret = -EINVAL;
717 goto err;
718 }
719 }
720
721 len -= sock_hlen;
722 copied = copy_from_iter(buf + pad, len, from);
723 if (copied != len) {
724 ret = -EFAULT;
725 goto err;
726 }
727
728 xdp_init_buff(xdp, buflen, NULL);
729 xdp_prepare_buff(xdp, buf, pad, len, true);
730 hdr->buflen = buflen;
731
732 ++nvq->batched_xdp;
733
734 return 0;
735
736err:
737 page_frag_free(buf);
738 return ret;
739}
740
741static void handle_tx_copy(struct vhost_net *net, struct socket *sock)
742{
743 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
744 struct vhost_virtqueue *vq = &nvq->vq;
745 unsigned out, in;
746 int head;
747 struct msghdr msg = {
748 .msg_name = NULL,
749 .msg_namelen = 0,
750 .msg_control = NULL,
751 .msg_controllen = 0,
752 .msg_flags = MSG_DONTWAIT,
753 };
754 size_t len, total_len = 0;
755 int err;
756 int sent_pkts = 0;
757 bool sock_can_batch = (sock->sk->sk_sndbuf == INT_MAX);
758 bool busyloop_intr;
759
760 do {
761 busyloop_intr = false;
762 if (nvq->done_idx == VHOST_NET_BATCH)
763 vhost_tx_batch(net, nvq, sock, &msg);
764
765 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len,
766 &busyloop_intr);
767 /* On error, stop handling until the next kick. */
768 if (unlikely(head < 0))
769 break;
770 /* Nothing new? Wait for eventfd to tell us they refilled. */
771 if (head == vq->num) {
772 /* Kicks are disabled at this point, break loop and
773 * process any remaining batched packets. Queue will
774 * be re-enabled afterwards.
775 */
776 break;
777 }
778
779 total_len += len;
780
781 /* For simplicity, TX batching is only enabled if
782 * sndbuf is unlimited.
783 */
784 if (sock_can_batch) {
785 err = vhost_net_build_xdp(nvq, &msg.msg_iter);
786 if (!err) {
787 goto done;
788 } else if (unlikely(err != -ENOSPC)) {
789 vhost_tx_batch(net, nvq, sock, &msg);
790 vhost_discard_vq_desc(vq, 1);
791 vhost_net_enable_vq(net, vq);
792 break;
793 }
794
795 /* We can't build XDP buff, go for single
796 * packet path but let's flush batched
797 * packets.
798 */
799 vhost_tx_batch(net, nvq, sock, &msg);
800 msg.msg_control = NULL;
801 } else {
802 if (tx_can_batch(vq, total_len))
803 msg.msg_flags |= MSG_MORE;
804 else
805 msg.msg_flags &= ~MSG_MORE;
806 }
807
808 err = sock->ops->sendmsg(sock, &msg, len);
809 if (unlikely(err < 0)) {
810 if (err == -EAGAIN || err == -ENOMEM || err == -ENOBUFS) {
811 vhost_discard_vq_desc(vq, 1);
812 vhost_net_enable_vq(net, vq);
813 break;
814 }
815 pr_debug("Fail to send packet: err %d", err);
816 } else if (unlikely(err != len))
817 pr_debug("Truncated TX packet: len %d != %zd\n",
818 err, len);
819done:
820 vq->heads[nvq->done_idx].id = cpu_to_vhost32(vq, head);
821 vq->heads[nvq->done_idx].len = 0;
822 ++nvq->done_idx;
823 } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len)));
824
825 /* Kicks are still disabled, dispatch any remaining batched msgs. */
826 vhost_tx_batch(net, nvq, sock, &msg);
827
828 if (unlikely(busyloop_intr))
829 /* If interrupted while doing busy polling, requeue the
830 * handler to be fair handle_rx as well as other tasks
831 * waiting on cpu.
832 */
833 vhost_poll_queue(&vq->poll);
834 else
835 /* All of our work has been completed; however, before
836 * leaving the TX handler, do one last check for work,
837 * and requeue handler if necessary. If there is no work,
838 * queue will be reenabled.
839 */
840 vhost_net_busy_poll_try_queue(net, vq);
841}
842
843static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock)
844{
845 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
846 struct vhost_virtqueue *vq = &nvq->vq;
847 unsigned out, in;
848 int head;
849 struct msghdr msg = {
850 .msg_name = NULL,
851 .msg_namelen = 0,
852 .msg_control = NULL,
853 .msg_controllen = 0,
854 .msg_flags = MSG_DONTWAIT,
855 };
856 struct tun_msg_ctl ctl;
857 size_t len, total_len = 0;
858 int err;
859 struct vhost_net_ubuf_ref *ubufs;
860 struct ubuf_info_msgzc *ubuf;
861 bool zcopy_used;
862 int sent_pkts = 0;
863
864 do {
865 bool busyloop_intr;
866
867 /* Release DMAs done buffers first */
868 vhost_zerocopy_signal_used(net, vq);
869
870 busyloop_intr = false;
871 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len,
872 &busyloop_intr);
873 /* On error, stop handling until the next kick. */
874 if (unlikely(head < 0))
875 break;
876 /* Nothing new? Wait for eventfd to tell us they refilled. */
877 if (head == vq->num) {
878 if (unlikely(busyloop_intr)) {
879 vhost_poll_queue(&vq->poll);
880 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) {
881 vhost_disable_notify(&net->dev, vq);
882 continue;
883 }
884 break;
885 }
886
887 zcopy_used = len >= VHOST_GOODCOPY_LEN
888 && !vhost_exceeds_maxpend(net)
889 && vhost_net_tx_select_zcopy(net);
890
891 /* use msg_control to pass vhost zerocopy ubuf info to skb */
892 if (zcopy_used) {
893 ubuf = nvq->ubuf_info + nvq->upend_idx;
894 vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head);
895 vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS;
896 ubuf->ctx = nvq->ubufs;
897 ubuf->desc = nvq->upend_idx;
898 ubuf->ubuf.ops = &vhost_ubuf_ops;
899 ubuf->ubuf.flags = SKBFL_ZEROCOPY_FRAG;
900 refcount_set(&ubuf->ubuf.refcnt, 1);
901 msg.msg_control = &ctl;
902 ctl.type = TUN_MSG_UBUF;
903 ctl.ptr = &ubuf->ubuf;
904 msg.msg_controllen = sizeof(ctl);
905 ubufs = nvq->ubufs;
906 atomic_inc(&ubufs->refcount);
907 nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV;
908 } else {
909 msg.msg_control = NULL;
910 ubufs = NULL;
911 }
912 total_len += len;
913 if (tx_can_batch(vq, total_len) &&
914 likely(!vhost_exceeds_maxpend(net))) {
915 msg.msg_flags |= MSG_MORE;
916 } else {
917 msg.msg_flags &= ~MSG_MORE;
918 }
919
920 err = sock->ops->sendmsg(sock, &msg, len);
921 if (unlikely(err < 0)) {
922 bool retry = err == -EAGAIN || err == -ENOMEM || err == -ENOBUFS;
923
924 if (zcopy_used) {
925 if (vq->heads[ubuf->desc].len == VHOST_DMA_IN_PROGRESS)
926 vhost_net_ubuf_put(ubufs);
927 if (retry)
928 nvq->upend_idx = ((unsigned)nvq->upend_idx - 1)
929 % UIO_MAXIOV;
930 else
931 vq->heads[ubuf->desc].len = VHOST_DMA_DONE_LEN;
932 }
933 if (retry) {
934 vhost_discard_vq_desc(vq, 1);
935 vhost_net_enable_vq(net, vq);
936 break;
937 }
938 pr_debug("Fail to send packet: err %d", err);
939 } else if (unlikely(err != len))
940 pr_debug("Truncated TX packet: "
941 " len %d != %zd\n", err, len);
942 if (!zcopy_used)
943 vhost_add_used_and_signal(&net->dev, vq, head, 0);
944 else
945 vhost_zerocopy_signal_used(net, vq);
946 vhost_net_tx_packet(net);
947 } while (likely(!vhost_exceeds_weight(vq, ++sent_pkts, total_len)));
948}
949
950/* Expects to be always run from workqueue - which acts as
951 * read-size critical section for our kind of RCU. */
952static void handle_tx(struct vhost_net *net)
953{
954 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX];
955 struct vhost_virtqueue *vq = &nvq->vq;
956 struct socket *sock;
957
958 mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_TX);
959 sock = vhost_vq_get_backend(vq);
960 if (!sock)
961 goto out;
962
963 if (!vq_meta_prefetch(vq))
964 goto out;
965
966 vhost_disable_notify(&net->dev, vq);
967 vhost_net_disable_vq(net, vq);
968
969 if (vhost_sock_zcopy(sock))
970 handle_tx_zerocopy(net, sock);
971 else
972 handle_tx_copy(net, sock);
973
974out:
975 mutex_unlock(&vq->mutex);
976}
977
978static int peek_head_len(struct vhost_net_virtqueue *rvq, struct sock *sk)
979{
980 struct sk_buff *head;
981 int len = 0;
982 unsigned long flags;
983
984 if (rvq->rx_ring)
985 return vhost_net_buf_peek(rvq);
986
987 spin_lock_irqsave(&sk->sk_receive_queue.lock, flags);
988 head = skb_peek(&sk->sk_receive_queue);
989 if (likely(head)) {
990 len = head->len;
991 if (skb_vlan_tag_present(head))
992 len += VLAN_HLEN;
993 }
994
995 spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags);
996 return len;
997}
998
999static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk,
1000 bool *busyloop_intr)
1001{
1002 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX];
1003 struct vhost_net_virtqueue *tnvq = &net->vqs[VHOST_NET_VQ_TX];
1004 struct vhost_virtqueue *rvq = &rnvq->vq;
1005 struct vhost_virtqueue *tvq = &tnvq->vq;
1006 int len = peek_head_len(rnvq, sk);
1007
1008 if (!len && rvq->busyloop_timeout) {
1009 /* Flush batched heads first */
1010 vhost_net_signal_used(rnvq);
1011 /* Both tx vq and rx socket were polled here */
1012 vhost_net_busy_poll(net, rvq, tvq, busyloop_intr, true);
1013
1014 len = peek_head_len(rnvq, sk);
1015 }
1016
1017 return len;
1018}
1019
1020/* This is a multi-buffer version of vhost_get_desc, that works if
1021 * vq has read descriptors only.
1022 * @vq - the relevant virtqueue
1023 * @datalen - data length we'll be reading
1024 * @iovcount - returned count of io vectors we fill
1025 * @log - vhost log
1026 * @log_num - log offset
1027 * @quota - headcount quota, 1 for big buffer
1028 * returns number of buffer heads allocated, negative on error
1029 */
1030static int get_rx_bufs(struct vhost_virtqueue *vq,
1031 struct vring_used_elem *heads,
1032 int datalen,
1033 unsigned *iovcount,
1034 struct vhost_log *log,
1035 unsigned *log_num,
1036 unsigned int quota)
1037{
1038 unsigned int out, in;
1039 int seg = 0;
1040 int headcount = 0;
1041 unsigned d;
1042 int r, nlogs = 0;
1043 /* len is always initialized before use since we are always called with
1044 * datalen > 0.
1045 */
1046 u32 len;
1047
1048 while (datalen > 0 && headcount < quota) {
1049 if (unlikely(seg >= UIO_MAXIOV)) {
1050 r = -ENOBUFS;
1051 goto err;
1052 }
1053 r = vhost_get_vq_desc(vq, vq->iov + seg,
1054 ARRAY_SIZE(vq->iov) - seg, &out,
1055 &in, log, log_num);
1056 if (unlikely(r < 0))
1057 goto err;
1058
1059 d = r;
1060 if (d == vq->num) {
1061 r = 0;
1062 goto err;
1063 }
1064 if (unlikely(out || in <= 0)) {
1065 vq_err(vq, "unexpected descriptor format for RX: "
1066 "out %d, in %d\n", out, in);
1067 r = -EINVAL;
1068 goto err;
1069 }
1070 if (unlikely(log)) {
1071 nlogs += *log_num;
1072 log += *log_num;
1073 }
1074 heads[headcount].id = cpu_to_vhost32(vq, d);
1075 len = iov_length(vq->iov + seg, in);
1076 heads[headcount].len = cpu_to_vhost32(vq, len);
1077 datalen -= len;
1078 ++headcount;
1079 seg += in;
1080 }
1081 heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen);
1082 *iovcount = seg;
1083 if (unlikely(log))
1084 *log_num = nlogs;
1085
1086 /* Detect overrun */
1087 if (unlikely(datalen > 0)) {
1088 r = UIO_MAXIOV + 1;
1089 goto err;
1090 }
1091 return headcount;
1092err:
1093 vhost_discard_vq_desc(vq, headcount);
1094 return r;
1095}
1096
1097/* Expects to be always run from workqueue - which acts as
1098 * read-size critical section for our kind of RCU. */
1099static void handle_rx(struct vhost_net *net)
1100{
1101 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX];
1102 struct vhost_virtqueue *vq = &nvq->vq;
1103 unsigned in, log;
1104 struct vhost_log *vq_log;
1105 struct msghdr msg = {
1106 .msg_name = NULL,
1107 .msg_namelen = 0,
1108 .msg_control = NULL, /* FIXME: get and handle RX aux data. */
1109 .msg_controllen = 0,
1110 .msg_flags = MSG_DONTWAIT,
1111 };
1112 struct virtio_net_hdr hdr = {
1113 .flags = 0,
1114 .gso_type = VIRTIO_NET_HDR_GSO_NONE
1115 };
1116 size_t total_len = 0;
1117 int err, mergeable;
1118 s16 headcount;
1119 size_t vhost_hlen, sock_hlen;
1120 size_t vhost_len, sock_len;
1121 bool busyloop_intr = false;
1122 bool set_num_buffers;
1123 struct socket *sock;
1124 struct iov_iter fixup;
1125 __virtio16 num_buffers;
1126 int recv_pkts = 0;
1127
1128 mutex_lock_nested(&vq->mutex, VHOST_NET_VQ_RX);
1129 sock = vhost_vq_get_backend(vq);
1130 if (!sock)
1131 goto out;
1132
1133 if (!vq_meta_prefetch(vq))
1134 goto out;
1135
1136 vhost_disable_notify(&net->dev, vq);
1137 vhost_net_disable_vq(net, vq);
1138
1139 vhost_hlen = nvq->vhost_hlen;
1140 sock_hlen = nvq->sock_hlen;
1141
1142 vq_log = unlikely(vhost_has_feature(vq, VHOST_F_LOG_ALL)) ?
1143 vq->log : NULL;
1144 mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF);
1145 set_num_buffers = mergeable ||
1146 vhost_has_feature(vq, VIRTIO_F_VERSION_1);
1147
1148 do {
1149 sock_len = vhost_net_rx_peek_head_len(net, sock->sk,
1150 &busyloop_intr);
1151 if (!sock_len)
1152 break;
1153 sock_len += sock_hlen;
1154 vhost_len = sock_len + vhost_hlen;
1155 headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx,
1156 vhost_len, &in, vq_log, &log,
1157 likely(mergeable) ? UIO_MAXIOV : 1);
1158 /* On error, stop handling until the next kick. */
1159 if (unlikely(headcount < 0))
1160 goto out;
1161 /* OK, now we need to know about added descriptors. */
1162 if (!headcount) {
1163 if (unlikely(busyloop_intr)) {
1164 vhost_poll_queue(&vq->poll);
1165 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) {
1166 /* They have slipped one in as we were
1167 * doing that: check again. */
1168 vhost_disable_notify(&net->dev, vq);
1169 continue;
1170 }
1171 /* Nothing new? Wait for eventfd to tell us
1172 * they refilled. */
1173 goto out;
1174 }
1175 busyloop_intr = false;
1176 if (nvq->rx_ring)
1177 msg.msg_control = vhost_net_buf_consume(&nvq->rxq);
1178 /* On overrun, truncate and discard */
1179 if (unlikely(headcount > UIO_MAXIOV)) {
1180 iov_iter_init(&msg.msg_iter, ITER_DEST, vq->iov, 1, 1);
1181 err = sock->ops->recvmsg(sock, &msg,
1182 1, MSG_DONTWAIT | MSG_TRUNC);
1183 pr_debug("Discarded rx packet: len %zd\n", sock_len);
1184 continue;
1185 }
1186 /* We don't need to be notified again. */
1187 iov_iter_init(&msg.msg_iter, ITER_DEST, vq->iov, in, vhost_len);
1188 fixup = msg.msg_iter;
1189 if (unlikely((vhost_hlen))) {
1190 /* We will supply the header ourselves
1191 * TODO: support TSO.
1192 */
1193 iov_iter_advance(&msg.msg_iter, vhost_hlen);
1194 }
1195 err = sock->ops->recvmsg(sock, &msg,
1196 sock_len, MSG_DONTWAIT | MSG_TRUNC);
1197 /* Userspace might have consumed the packet meanwhile:
1198 * it's not supposed to do this usually, but might be hard
1199 * to prevent. Discard data we got (if any) and keep going. */
1200 if (unlikely(err != sock_len)) {
1201 pr_debug("Discarded rx packet: "
1202 " len %d, expected %zd\n", err, sock_len);
1203 vhost_discard_vq_desc(vq, headcount);
1204 continue;
1205 }
1206 /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */
1207 if (unlikely(vhost_hlen)) {
1208 if (copy_to_iter(&hdr, sizeof(hdr),
1209 &fixup) != sizeof(hdr)) {
1210 vq_err(vq, "Unable to write vnet_hdr "
1211 "at addr %p\n", vq->iov->iov_base);
1212 goto out;
1213 }
1214 } else {
1215 /* Header came from socket; we'll need to patch
1216 * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF
1217 */
1218 iov_iter_advance(&fixup, sizeof(hdr));
1219 }
1220 /* TODO: Should check and handle checksum. */
1221
1222 num_buffers = cpu_to_vhost16(vq, headcount);
1223 if (likely(set_num_buffers) &&
1224 copy_to_iter(&num_buffers, sizeof num_buffers,
1225 &fixup) != sizeof num_buffers) {
1226 vq_err(vq, "Failed num_buffers write");
1227 vhost_discard_vq_desc(vq, headcount);
1228 goto out;
1229 }
1230 nvq->done_idx += headcount;
1231 if (nvq->done_idx > VHOST_NET_BATCH)
1232 vhost_net_signal_used(nvq);
1233 if (unlikely(vq_log))
1234 vhost_log_write(vq, vq_log, log, vhost_len,
1235 vq->iov, in);
1236 total_len += vhost_len;
1237 } while (likely(!vhost_exceeds_weight(vq, ++recv_pkts, total_len)));
1238
1239 if (unlikely(busyloop_intr))
1240 vhost_poll_queue(&vq->poll);
1241 else if (!sock_len)
1242 vhost_net_enable_vq(net, vq);
1243out:
1244 vhost_net_signal_used(nvq);
1245 mutex_unlock(&vq->mutex);
1246}
1247
1248static void handle_tx_kick(struct vhost_work *work)
1249{
1250 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
1251 poll.work);
1252 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
1253
1254 handle_tx(net);
1255}
1256
1257static void handle_rx_kick(struct vhost_work *work)
1258{
1259 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
1260 poll.work);
1261 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev);
1262
1263 handle_rx(net);
1264}
1265
1266static void handle_tx_net(struct vhost_work *work)
1267{
1268 struct vhost_net *net = container_of(work, struct vhost_net,
1269 poll[VHOST_NET_VQ_TX].work);
1270 handle_tx(net);
1271}
1272
1273static void handle_rx_net(struct vhost_work *work)
1274{
1275 struct vhost_net *net = container_of(work, struct vhost_net,
1276 poll[VHOST_NET_VQ_RX].work);
1277 handle_rx(net);
1278}
1279
1280static int vhost_net_open(struct inode *inode, struct file *f)
1281{
1282 struct vhost_net *n;
1283 struct vhost_dev *dev;
1284 struct vhost_virtqueue **vqs;
1285 void **queue;
1286 struct xdp_buff *xdp;
1287 int i;
1288
1289 n = kvmalloc(sizeof *n, GFP_KERNEL | __GFP_RETRY_MAYFAIL);
1290 if (!n)
1291 return -ENOMEM;
1292 vqs = kmalloc_array(VHOST_NET_VQ_MAX, sizeof(*vqs), GFP_KERNEL);
1293 if (!vqs) {
1294 kvfree(n);
1295 return -ENOMEM;
1296 }
1297
1298 queue = kmalloc_array(VHOST_NET_BATCH, sizeof(void *),
1299 GFP_KERNEL);
1300 if (!queue) {
1301 kfree(vqs);
1302 kvfree(n);
1303 return -ENOMEM;
1304 }
1305 n->vqs[VHOST_NET_VQ_RX].rxq.queue = queue;
1306
1307 xdp = kmalloc_array(VHOST_NET_BATCH, sizeof(*xdp), GFP_KERNEL);
1308 if (!xdp) {
1309 kfree(vqs);
1310 kvfree(n);
1311 kfree(queue);
1312 return -ENOMEM;
1313 }
1314 n->vqs[VHOST_NET_VQ_TX].xdp = xdp;
1315
1316 dev = &n->dev;
1317 vqs[VHOST_NET_VQ_TX] = &n->vqs[VHOST_NET_VQ_TX].vq;
1318 vqs[VHOST_NET_VQ_RX] = &n->vqs[VHOST_NET_VQ_RX].vq;
1319 n->vqs[VHOST_NET_VQ_TX].vq.handle_kick = handle_tx_kick;
1320 n->vqs[VHOST_NET_VQ_RX].vq.handle_kick = handle_rx_kick;
1321 for (i = 0; i < VHOST_NET_VQ_MAX; i++) {
1322 n->vqs[i].ubufs = NULL;
1323 n->vqs[i].ubuf_info = NULL;
1324 n->vqs[i].upend_idx = 0;
1325 n->vqs[i].done_idx = 0;
1326 n->vqs[i].batched_xdp = 0;
1327 n->vqs[i].vhost_hlen = 0;
1328 n->vqs[i].sock_hlen = 0;
1329 n->vqs[i].rx_ring = NULL;
1330 vhost_net_buf_init(&n->vqs[i].rxq);
1331 }
1332 vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX,
1333 UIO_MAXIOV + VHOST_NET_BATCH,
1334 VHOST_NET_PKT_WEIGHT, VHOST_NET_WEIGHT, true,
1335 NULL);
1336
1337 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, EPOLLOUT, dev,
1338 vqs[VHOST_NET_VQ_TX]);
1339 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, EPOLLIN, dev,
1340 vqs[VHOST_NET_VQ_RX]);
1341
1342 f->private_data = n;
1343 page_frag_cache_init(&n->pf_cache);
1344
1345 return 0;
1346}
1347
1348static struct socket *vhost_net_stop_vq(struct vhost_net *n,
1349 struct vhost_virtqueue *vq)
1350{
1351 struct socket *sock;
1352 struct vhost_net_virtqueue *nvq =
1353 container_of(vq, struct vhost_net_virtqueue, vq);
1354
1355 mutex_lock(&vq->mutex);
1356 sock = vhost_vq_get_backend(vq);
1357 vhost_net_disable_vq(n, vq);
1358 vhost_vq_set_backend(vq, NULL);
1359 vhost_net_buf_unproduce(nvq);
1360 nvq->rx_ring = NULL;
1361 mutex_unlock(&vq->mutex);
1362 return sock;
1363}
1364
1365static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock,
1366 struct socket **rx_sock)
1367{
1368 *tx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_TX].vq);
1369 *rx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_RX].vq);
1370}
1371
1372static void vhost_net_flush(struct vhost_net *n)
1373{
1374 vhost_dev_flush(&n->dev);
1375 if (n->vqs[VHOST_NET_VQ_TX].ubufs) {
1376 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1377 n->tx_flush = true;
1378 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1379 /* Wait for all lower device DMAs done. */
1380 vhost_net_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs);
1381 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1382 n->tx_flush = false;
1383 atomic_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1);
1384 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1385 }
1386}
1387
1388static int vhost_net_release(struct inode *inode, struct file *f)
1389{
1390 struct vhost_net *n = f->private_data;
1391 struct socket *tx_sock;
1392 struct socket *rx_sock;
1393
1394 vhost_net_stop(n, &tx_sock, &rx_sock);
1395 vhost_net_flush(n);
1396 vhost_dev_stop(&n->dev);
1397 vhost_dev_cleanup(&n->dev);
1398 vhost_net_vq_reset(n);
1399 if (tx_sock)
1400 sockfd_put(tx_sock);
1401 if (rx_sock)
1402 sockfd_put(rx_sock);
1403 /* Make sure no callbacks are outstanding */
1404 synchronize_rcu();
1405 /* We do an extra flush before freeing memory,
1406 * since jobs can re-queue themselves. */
1407 vhost_net_flush(n);
1408 kfree(n->vqs[VHOST_NET_VQ_RX].rxq.queue);
1409 kfree(n->vqs[VHOST_NET_VQ_TX].xdp);
1410 kfree(n->dev.vqs);
1411 page_frag_cache_drain(&n->pf_cache);
1412 kvfree(n);
1413 return 0;
1414}
1415
1416static struct socket *get_raw_socket(int fd)
1417{
1418 int r;
1419 struct socket *sock = sockfd_lookup(fd, &r);
1420
1421 if (!sock)
1422 return ERR_PTR(-ENOTSOCK);
1423
1424 /* Parameter checking */
1425 if (sock->sk->sk_type != SOCK_RAW) {
1426 r = -ESOCKTNOSUPPORT;
1427 goto err;
1428 }
1429
1430 if (sock->sk->sk_family != AF_PACKET) {
1431 r = -EPFNOSUPPORT;
1432 goto err;
1433 }
1434 return sock;
1435err:
1436 sockfd_put(sock);
1437 return ERR_PTR(r);
1438}
1439
1440static struct ptr_ring *get_tap_ptr_ring(struct file *file)
1441{
1442 struct ptr_ring *ring;
1443 ring = tun_get_tx_ring(file);
1444 if (!IS_ERR(ring))
1445 goto out;
1446 ring = tap_get_ptr_ring(file);
1447 if (!IS_ERR(ring))
1448 goto out;
1449 ring = NULL;
1450out:
1451 return ring;
1452}
1453
1454static struct socket *get_tap_socket(int fd)
1455{
1456 struct file *file = fget(fd);
1457 struct socket *sock;
1458
1459 if (!file)
1460 return ERR_PTR(-EBADF);
1461 sock = tun_get_socket(file);
1462 if (!IS_ERR(sock))
1463 return sock;
1464 sock = tap_get_socket(file);
1465 if (IS_ERR(sock))
1466 fput(file);
1467 return sock;
1468}
1469
1470static struct socket *get_socket(int fd)
1471{
1472 struct socket *sock;
1473
1474 /* special case to disable backend */
1475 if (fd == -1)
1476 return NULL;
1477 sock = get_raw_socket(fd);
1478 if (!IS_ERR(sock))
1479 return sock;
1480 sock = get_tap_socket(fd);
1481 if (!IS_ERR(sock))
1482 return sock;
1483 return ERR_PTR(-ENOTSOCK);
1484}
1485
1486static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
1487{
1488 struct socket *sock, *oldsock;
1489 struct vhost_virtqueue *vq;
1490 struct vhost_net_virtqueue *nvq;
1491 struct vhost_net_ubuf_ref *ubufs, *oldubufs = NULL;
1492 int r;
1493
1494 mutex_lock(&n->dev.mutex);
1495 r = vhost_dev_check_owner(&n->dev);
1496 if (r)
1497 goto err;
1498
1499 if (index >= VHOST_NET_VQ_MAX) {
1500 r = -ENOBUFS;
1501 goto err;
1502 }
1503 vq = &n->vqs[index].vq;
1504 nvq = &n->vqs[index];
1505 mutex_lock(&vq->mutex);
1506
1507 if (fd == -1)
1508 vhost_clear_msg(&n->dev);
1509
1510 /* Verify that ring has been setup correctly. */
1511 if (!vhost_vq_access_ok(vq)) {
1512 r = -EFAULT;
1513 goto err_vq;
1514 }
1515 sock = get_socket(fd);
1516 if (IS_ERR(sock)) {
1517 r = PTR_ERR(sock);
1518 goto err_vq;
1519 }
1520
1521 /* start polling new socket */
1522 oldsock = vhost_vq_get_backend(vq);
1523 if (sock != oldsock) {
1524 ubufs = vhost_net_ubuf_alloc(vq,
1525 sock && vhost_sock_zcopy(sock));
1526 if (IS_ERR(ubufs)) {
1527 r = PTR_ERR(ubufs);
1528 goto err_ubufs;
1529 }
1530
1531 vhost_net_disable_vq(n, vq);
1532 vhost_vq_set_backend(vq, sock);
1533 vhost_net_buf_unproduce(nvq);
1534 r = vhost_vq_init_access(vq);
1535 if (r)
1536 goto err_used;
1537 r = vhost_net_enable_vq(n, vq);
1538 if (r)
1539 goto err_used;
1540 if (index == VHOST_NET_VQ_RX) {
1541 if (sock)
1542 nvq->rx_ring = get_tap_ptr_ring(sock->file);
1543 else
1544 nvq->rx_ring = NULL;
1545 }
1546
1547 oldubufs = nvq->ubufs;
1548 nvq->ubufs = ubufs;
1549
1550 n->tx_packets = 0;
1551 n->tx_zcopy_err = 0;
1552 n->tx_flush = false;
1553 }
1554
1555 mutex_unlock(&vq->mutex);
1556
1557 if (oldubufs) {
1558 vhost_net_ubuf_put_wait_and_free(oldubufs);
1559 mutex_lock(&vq->mutex);
1560 vhost_zerocopy_signal_used(n, vq);
1561 mutex_unlock(&vq->mutex);
1562 }
1563
1564 if (oldsock) {
1565 vhost_dev_flush(&n->dev);
1566 sockfd_put(oldsock);
1567 }
1568
1569 mutex_unlock(&n->dev.mutex);
1570 return 0;
1571
1572err_used:
1573 vhost_vq_set_backend(vq, oldsock);
1574 vhost_net_enable_vq(n, vq);
1575 if (ubufs)
1576 vhost_net_ubuf_put_wait_and_free(ubufs);
1577err_ubufs:
1578 if (sock)
1579 sockfd_put(sock);
1580err_vq:
1581 mutex_unlock(&vq->mutex);
1582err:
1583 mutex_unlock(&n->dev.mutex);
1584 return r;
1585}
1586
1587static long vhost_net_reset_owner(struct vhost_net *n)
1588{
1589 struct socket *tx_sock = NULL;
1590 struct socket *rx_sock = NULL;
1591 long err;
1592 struct vhost_iotlb *umem;
1593
1594 mutex_lock(&n->dev.mutex);
1595 err = vhost_dev_check_owner(&n->dev);
1596 if (err)
1597 goto done;
1598 umem = vhost_dev_reset_owner_prepare();
1599 if (!umem) {
1600 err = -ENOMEM;
1601 goto done;
1602 }
1603 vhost_net_stop(n, &tx_sock, &rx_sock);
1604 vhost_net_flush(n);
1605 vhost_dev_stop(&n->dev);
1606 vhost_dev_reset_owner(&n->dev, umem);
1607 vhost_net_vq_reset(n);
1608done:
1609 mutex_unlock(&n->dev.mutex);
1610 if (tx_sock)
1611 sockfd_put(tx_sock);
1612 if (rx_sock)
1613 sockfd_put(rx_sock);
1614 return err;
1615}
1616
1617static int vhost_net_set_features(struct vhost_net *n, u64 features)
1618{
1619 size_t vhost_hlen, sock_hlen, hdr_len;
1620 int i;
1621
1622 hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) |
1623 (1ULL << VIRTIO_F_VERSION_1))) ?
1624 sizeof(struct virtio_net_hdr_mrg_rxbuf) :
1625 sizeof(struct virtio_net_hdr);
1626 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) {
1627 /* vhost provides vnet_hdr */
1628 vhost_hlen = hdr_len;
1629 sock_hlen = 0;
1630 } else {
1631 /* socket provides vnet_hdr */
1632 vhost_hlen = 0;
1633 sock_hlen = hdr_len;
1634 }
1635 mutex_lock(&n->dev.mutex);
1636 if ((features & (1 << VHOST_F_LOG_ALL)) &&
1637 !vhost_log_access_ok(&n->dev))
1638 goto out_unlock;
1639
1640 if ((features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) {
1641 if (vhost_init_device_iotlb(&n->dev))
1642 goto out_unlock;
1643 }
1644
1645 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
1646 mutex_lock(&n->vqs[i].vq.mutex);
1647 n->vqs[i].vq.acked_features = features;
1648 n->vqs[i].vhost_hlen = vhost_hlen;
1649 n->vqs[i].sock_hlen = sock_hlen;
1650 mutex_unlock(&n->vqs[i].vq.mutex);
1651 }
1652 mutex_unlock(&n->dev.mutex);
1653 return 0;
1654
1655out_unlock:
1656 mutex_unlock(&n->dev.mutex);
1657 return -EFAULT;
1658}
1659
1660static long vhost_net_set_owner(struct vhost_net *n)
1661{
1662 int r;
1663
1664 mutex_lock(&n->dev.mutex);
1665 if (vhost_dev_has_owner(&n->dev)) {
1666 r = -EBUSY;
1667 goto out;
1668 }
1669 r = vhost_net_set_ubuf_info(n);
1670 if (r)
1671 goto out;
1672 r = vhost_dev_set_owner(&n->dev);
1673 if (r)
1674 vhost_net_clear_ubuf_info(n);
1675 vhost_net_flush(n);
1676out:
1677 mutex_unlock(&n->dev.mutex);
1678 return r;
1679}
1680
1681static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
1682 unsigned long arg)
1683{
1684 struct vhost_net *n = f->private_data;
1685 void __user *argp = (void __user *)arg;
1686 u64 __user *featurep = argp;
1687 struct vhost_vring_file backend;
1688 u64 features;
1689 int r;
1690
1691 switch (ioctl) {
1692 case VHOST_NET_SET_BACKEND:
1693 if (copy_from_user(&backend, argp, sizeof backend))
1694 return -EFAULT;
1695 return vhost_net_set_backend(n, backend.index, backend.fd);
1696 case VHOST_GET_FEATURES:
1697 features = VHOST_NET_FEATURES;
1698 if (copy_to_user(featurep, &features, sizeof features))
1699 return -EFAULT;
1700 return 0;
1701 case VHOST_SET_FEATURES:
1702 if (copy_from_user(&features, featurep, sizeof features))
1703 return -EFAULT;
1704 if (features & ~VHOST_NET_FEATURES)
1705 return -EOPNOTSUPP;
1706 return vhost_net_set_features(n, features);
1707 case VHOST_GET_BACKEND_FEATURES:
1708 features = VHOST_NET_BACKEND_FEATURES;
1709 if (copy_to_user(featurep, &features, sizeof(features)))
1710 return -EFAULT;
1711 return 0;
1712 case VHOST_SET_BACKEND_FEATURES:
1713 if (copy_from_user(&features, featurep, sizeof(features)))
1714 return -EFAULT;
1715 if (features & ~VHOST_NET_BACKEND_FEATURES)
1716 return -EOPNOTSUPP;
1717 vhost_set_backend_features(&n->dev, features);
1718 return 0;
1719 case VHOST_RESET_OWNER:
1720 return vhost_net_reset_owner(n);
1721 case VHOST_SET_OWNER:
1722 return vhost_net_set_owner(n);
1723 default:
1724 mutex_lock(&n->dev.mutex);
1725 r = vhost_dev_ioctl(&n->dev, ioctl, argp);
1726 if (r == -ENOIOCTLCMD)
1727 r = vhost_vring_ioctl(&n->dev, ioctl, argp);
1728 else
1729 vhost_net_flush(n);
1730 mutex_unlock(&n->dev.mutex);
1731 return r;
1732 }
1733}
1734
1735static ssize_t vhost_net_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1736{
1737 struct file *file = iocb->ki_filp;
1738 struct vhost_net *n = file->private_data;
1739 struct vhost_dev *dev = &n->dev;
1740 int noblock = file->f_flags & O_NONBLOCK;
1741
1742 return vhost_chr_read_iter(dev, to, noblock);
1743}
1744
1745static ssize_t vhost_net_chr_write_iter(struct kiocb *iocb,
1746 struct iov_iter *from)
1747{
1748 struct file *file = iocb->ki_filp;
1749 struct vhost_net *n = file->private_data;
1750 struct vhost_dev *dev = &n->dev;
1751
1752 return vhost_chr_write_iter(dev, from);
1753}
1754
1755static __poll_t vhost_net_chr_poll(struct file *file, poll_table *wait)
1756{
1757 struct vhost_net *n = file->private_data;
1758 struct vhost_dev *dev = &n->dev;
1759
1760 return vhost_chr_poll(file, dev, wait);
1761}
1762
1763static const struct file_operations vhost_net_fops = {
1764 .owner = THIS_MODULE,
1765 .release = vhost_net_release,
1766 .read_iter = vhost_net_chr_read_iter,
1767 .write_iter = vhost_net_chr_write_iter,
1768 .poll = vhost_net_chr_poll,
1769 .unlocked_ioctl = vhost_net_ioctl,
1770 .compat_ioctl = compat_ptr_ioctl,
1771 .open = vhost_net_open,
1772 .llseek = noop_llseek,
1773};
1774
1775static struct miscdevice vhost_net_misc = {
1776 .minor = VHOST_NET_MINOR,
1777 .name = "vhost-net",
1778 .fops = &vhost_net_fops,
1779};
1780
1781static int __init vhost_net_init(void)
1782{
1783 if (experimental_zcopytx)
1784 vhost_net_enable_zcopy(VHOST_NET_VQ_TX);
1785 return misc_register(&vhost_net_misc);
1786}
1787module_init(vhost_net_init);
1788
1789static void __exit vhost_net_exit(void)
1790{
1791 misc_deregister(&vhost_net_misc);
1792}
1793module_exit(vhost_net_exit);
1794
1795MODULE_VERSION("0.0.1");
1796MODULE_LICENSE("GPL v2");
1797MODULE_AUTHOR("Michael S. Tsirkin");
1798MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
1799MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR);
1800MODULE_ALIAS("devname:vhost-net");
Linux 6.x block layer and io_uring tree(s)