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