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gpio: rcar: Fix runtime PM imbalance on error
[linux/fpc-iii.git] / drivers / vhost / net.c
blob87469d67ede8d889df6a855d90f7f05dcc2d44c5
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
38 static int experimental_zcopytx = 0;
39 module_param(experimental_zcopytx, int, 0444);
40 MODULE_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
72 enum {
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
79 enum {
80 VHOST_NET_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2)
81 };
82
83 enum {
84 VHOST_NET_VQ_RX = 0,
85 VHOST_NET_VQ_TX = 1,
86 VHOST_NET_VQ_MAX = 2,
87 };
88
89 struct 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
101 struct vhost_net_buf {
102 void **queue;
103 int tail;
104 int head;
105 };
106
107 struct 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
131 struct 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
149 static unsigned vhost_net_zcopy_mask __read_mostly;
150
151 static 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
159 static int vhost_net_buf_get_size(struct vhost_net_buf *rxq)
160 {
161 return rxq->tail - rxq->head;
162 }
163
164 static int vhost_net_buf_is_empty(struct vhost_net_buf *rxq)
165 {
166 return rxq->tail == rxq->head;
167 }
168
169 static 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
176 static 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
186 static 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
198 static 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
209 static 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
219 out:
220 return vhost_net_buf_peek_len(vhost_net_buf_get_ptr(rxq));
221 }
222
223 static void vhost_net_buf_init(struct vhost_net_buf *rxq)
224 {
225 rxq->head = rxq->tail = 0;
226 }
227
228 static void vhost_net_enable_zcopy(int vq)
229 {
230 vhost_net_zcopy_mask |= 0x1 << vq;
231 }
232
233 static struct vhost_net_ubuf_ref *
234 vhost_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
249 static 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
257 static 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
263 static 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
269 static 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
279 static 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
297 err:
298 vhost_net_clear_ubuf_info(n);
299 return -ENOMEM;
300 }
301
302 static 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
319 static 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
328 static void vhost_net_tx_err(struct vhost_net *net)
329 {
330 ++net->tx_zcopy_err;
331 }
332
333 static 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
342 static bool vhost_sock_zcopy(struct socket *sock)
343 {
344 return unlikely(experimental_zcopytx) &&
345 sock_flag(sock->sk, SOCK_ZEROCOPY);
346 }
347
348 static 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 */
358 static 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
384 static 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
410 static inline unsigned long busy_clock(void)
411 {
412 return local_clock() >> 10;
413 }
414
415 static 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
421 static 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
432 static 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
447 static 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
459 static 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
481 signal_used:
482 vhost_net_signal_used(nvq);
483 nvq->batched_xdp = 0;
484 }
485
486 static 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
497 static 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
508 static 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
559 static 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
585 static 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
594 static 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
606 static 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
637 static 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
645 static 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
674 done:
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
682 static 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
757 static 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);
837 done:
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
846 static 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. */
948 static 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
970 out:
971 mutex_unlock(&vq->mutex);
972 }
973
974 static 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
995 static 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 */
1026 static 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;
1088 err:
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. */
1095 static 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);
1236 out:
1237 vhost_net_signal_used(nvq);
1238 mutex_unlock(&vq->mutex);
1239 }
1240
1241 static 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
1250 static 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
1259 static 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
1266 static 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
1273 static 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 NULL);
1329
1330 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, EPOLLOUT, dev);
1331 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, EPOLLIN, dev);
1332
1333 f->private_data = n;
1334 n->page_frag.page = NULL;
1335 n->refcnt_bias = 0;
1336
1337 return 0;
1338 }
1339
1340 static struct socket *vhost_net_stop_vq(struct vhost_net *n,
1341 struct vhost_virtqueue *vq)
1342 {
1343 struct socket *sock;
1344 struct vhost_net_virtqueue *nvq =
1345 container_of(vq, struct vhost_net_virtqueue, vq);
1346
1347 mutex_lock(&vq->mutex);
1348 sock = vq->private_data;
1349 vhost_net_disable_vq(n, vq);
1350 vq->private_data = NULL;
1351 vhost_net_buf_unproduce(nvq);
1352 nvq->rx_ring = NULL;
1353 mutex_unlock(&vq->mutex);
1354 return sock;
1355 }
1356
1357 static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock,
1358 struct socket **rx_sock)
1359 {
1360 *tx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_TX].vq);
1361 *rx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_RX].vq);
1362 }
1363
1364 static void vhost_net_flush_vq(struct vhost_net *n, int index)
1365 {
1366 vhost_poll_flush(n->poll + index);
1367 vhost_poll_flush(&n->vqs[index].vq.poll);
1368 }
1369
1370 static void vhost_net_flush(struct vhost_net *n)
1371 {
1372 vhost_net_flush_vq(n, VHOST_NET_VQ_TX);
1373 vhost_net_flush_vq(n, VHOST_NET_VQ_RX);
1374 if (n->vqs[VHOST_NET_VQ_TX].ubufs) {
1375 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1376 n->tx_flush = true;
1377 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1378 /* Wait for all lower device DMAs done. */
1379 vhost_net_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs);
1380 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1381 n->tx_flush = false;
1382 atomic_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1);
1383 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex);
1384 }
1385 }
1386
1387 static int vhost_net_release(struct inode *inode, struct file *f)
1388 {
1389 struct vhost_net *n = f->private_data;
1390 struct socket *tx_sock;
1391 struct socket *rx_sock;
1392
1393 vhost_net_stop(n, &tx_sock, &rx_sock);
1394 vhost_net_flush(n);
1395 vhost_dev_stop(&n->dev);
1396 vhost_dev_cleanup(&n->dev);
1397 vhost_net_vq_reset(n);
1398 if (tx_sock)
1399 sockfd_put(tx_sock);
1400 if (rx_sock)
1401 sockfd_put(rx_sock);
1402 /* Make sure no callbacks are outstanding */
1403 synchronize_rcu();
1404 /* We do an extra flush before freeing memory,
1405 * since jobs can re-queue themselves. */
1406 vhost_net_flush(n);
1407 kfree(n->vqs[VHOST_NET_VQ_RX].rxq.queue);
1408 kfree(n->vqs[VHOST_NET_VQ_TX].xdp);
1409 kfree(n->dev.vqs);
1410 if (n->page_frag.page)
1411 __page_frag_cache_drain(n->page_frag.page, n->refcnt_bias);
1412 kvfree(n);
1413 return 0;
1414 }
1415
1416 static struct socket *get_raw_socket(int fd)
1417 {
1418 int r;
1419 struct socket *sock = sockfd_lookup(fd, &r);
1420
1421 if (!sock)
1422 return ERR_PTR(-ENOTSOCK);
1423
1424 /* Parameter checking */
1425 if (sock->sk->sk_type != SOCK_RAW) {
1426 r = -ESOCKTNOSUPPORT;
1427 goto err;
1428 }
1429
1430 if (sock->sk->sk_family != AF_PACKET) {
1431 r = -EPFNOSUPPORT;
1432 goto err;
1433 }
1434 return sock;
1435 err:
1436 sockfd_put(sock);
1437 return ERR_PTR(r);
1438 }
1439
1440 static struct ptr_ring *get_tap_ptr_ring(int fd)
1441 {
1442 struct ptr_ring *ring;
1443 struct file *file = fget(fd);
1444
1445 if (!file)
1446 return NULL;
1447 ring = tun_get_tx_ring(file);
1448 if (!IS_ERR(ring))
1449 goto out;
1450 ring = tap_get_ptr_ring(file);
1451 if (!IS_ERR(ring))
1452 goto out;
1453 ring = NULL;
1454 out:
1455 fput(file);
1456 return ring;
1457 }
1458
1459 static struct socket *get_tap_socket(int fd)
1460 {
1461 struct file *file = fget(fd);
1462 struct socket *sock;
1463
1464 if (!file)
1465 return ERR_PTR(-EBADF);
1466 sock = tun_get_socket(file);
1467 if (!IS_ERR(sock))
1468 return sock;
1469 sock = tap_get_socket(file);
1470 if (IS_ERR(sock))
1471 fput(file);
1472 return sock;
1473 }
1474
1475 static struct socket *get_socket(int fd)
1476 {
1477 struct socket *sock;
1478
1479 /* special case to disable backend */
1480 if (fd == -1)
1481 return NULL;
1482 sock = get_raw_socket(fd);
1483 if (!IS_ERR(sock))
1484 return sock;
1485 sock = get_tap_socket(fd);
1486 if (!IS_ERR(sock))
1487 return sock;
1488 return ERR_PTR(-ENOTSOCK);
1489 }
1490
1491 static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd)
1492 {
1493 struct socket *sock, *oldsock;
1494 struct vhost_virtqueue *vq;
1495 struct vhost_net_virtqueue *nvq;
1496 struct vhost_net_ubuf_ref *ubufs, *oldubufs = NULL;
1497 int r;
1498
1499 mutex_lock(&n->dev.mutex);
1500 r = vhost_dev_check_owner(&n->dev);
1501 if (r)
1502 goto err;
1503
1504 if (index >= VHOST_NET_VQ_MAX) {
1505 r = -ENOBUFS;
1506 goto err;
1507 }
1508 vq = &n->vqs[index].vq;
1509 nvq = &n->vqs[index];
1510 mutex_lock(&vq->mutex);
1511
1512 /* Verify that ring has been setup correctly. */
1513 if (!vhost_vq_access_ok(vq)) {
1514 r = -EFAULT;
1515 goto err_vq;
1516 }
1517 sock = get_socket(fd);
1518 if (IS_ERR(sock)) {
1519 r = PTR_ERR(sock);
1520 goto err_vq;
1521 }
1522
1523 /* start polling new socket */
1524 oldsock = vq->private_data;
1525 if (sock != oldsock) {
1526 ubufs = vhost_net_ubuf_alloc(vq,
1527 sock && vhost_sock_zcopy(sock));
1528 if (IS_ERR(ubufs)) {
1529 r = PTR_ERR(ubufs);
1530 goto err_ubufs;
1531 }
1532
1533 vhost_net_disable_vq(n, vq);
1534 vq->private_data = sock;
1535 vhost_net_buf_unproduce(nvq);
1536 r = vhost_vq_init_access(vq);
1537 if (r)
1538 goto err_used;
1539 r = vhost_net_enable_vq(n, vq);
1540 if (r)
1541 goto err_used;
1542 if (index == VHOST_NET_VQ_RX)
1543 nvq->rx_ring = get_tap_ptr_ring(fd);
1544
1545 oldubufs = nvq->ubufs;
1546 nvq->ubufs = ubufs;
1547
1548 n->tx_packets = 0;
1549 n->tx_zcopy_err = 0;
1550 n->tx_flush = false;
1551 }
1552
1553 mutex_unlock(&vq->mutex);
1554
1555 if (oldubufs) {
1556 vhost_net_ubuf_put_wait_and_free(oldubufs);
1557 mutex_lock(&vq->mutex);
1558 vhost_zerocopy_signal_used(n, vq);
1559 mutex_unlock(&vq->mutex);
1560 }
1561
1562 if (oldsock) {
1563 vhost_net_flush_vq(n, index);
1564 sockfd_put(oldsock);
1565 }
1566
1567 mutex_unlock(&n->dev.mutex);
1568 return 0;
1569
1570 err_used:
1571 vq->private_data = oldsock;
1572 vhost_net_enable_vq(n, vq);
1573 if (ubufs)
1574 vhost_net_ubuf_put_wait_and_free(ubufs);
1575 err_ubufs:
1576 if (sock)
1577 sockfd_put(sock);
1578 err_vq:
1579 mutex_unlock(&vq->mutex);
1580 err:
1581 mutex_unlock(&n->dev.mutex);
1582 return r;
1583 }
1584
1585 static long vhost_net_reset_owner(struct vhost_net *n)
1586 {
1587 struct socket *tx_sock = NULL;
1588 struct socket *rx_sock = NULL;
1589 long err;
1590 struct vhost_iotlb *umem;
1591
1592 mutex_lock(&n->dev.mutex);
1593 err = vhost_dev_check_owner(&n->dev);
1594 if (err)
1595 goto done;
1596 umem = vhost_dev_reset_owner_prepare();
1597 if (!umem) {
1598 err = -ENOMEM;
1599 goto done;
1600 }
1601 vhost_net_stop(n, &tx_sock, &rx_sock);
1602 vhost_net_flush(n);
1603 vhost_dev_stop(&n->dev);
1604 vhost_dev_reset_owner(&n->dev, umem);
1605 vhost_net_vq_reset(n);
1606 done:
1607 mutex_unlock(&n->dev.mutex);
1608 if (tx_sock)
1609 sockfd_put(tx_sock);
1610 if (rx_sock)
1611 sockfd_put(rx_sock);
1612 return err;
1613 }
1614
1615 static int vhost_net_set_backend_features(struct vhost_net *n, u64 features)
1616 {
1617 int i;
1618
1619 mutex_lock(&n->dev.mutex);
1620 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
1621 mutex_lock(&n->vqs[i].vq.mutex);
1622 n->vqs[i].vq.acked_backend_features = features;
1623 mutex_unlock(&n->vqs[i].vq.mutex);
1624 }
1625 mutex_unlock(&n->dev.mutex);
1626
1627 return 0;
1628 }
1629
1630 static int vhost_net_set_features(struct vhost_net *n, u64 features)
1631 {
1632 size_t vhost_hlen, sock_hlen, hdr_len;
1633 int i;
1634
1635 hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) |
1636 (1ULL << VIRTIO_F_VERSION_1))) ?
1637 sizeof(struct virtio_net_hdr_mrg_rxbuf) :
1638 sizeof(struct virtio_net_hdr);
1639 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) {
1640 /* vhost provides vnet_hdr */
1641 vhost_hlen = hdr_len;
1642 sock_hlen = 0;
1643 } else {
1644 /* socket provides vnet_hdr */
1645 vhost_hlen = 0;
1646 sock_hlen = hdr_len;
1647 }
1648 mutex_lock(&n->dev.mutex);
1649 if ((features & (1 << VHOST_F_LOG_ALL)) &&
1650 !vhost_log_access_ok(&n->dev))
1651 goto out_unlock;
1652
1653 if ((features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))) {
1654 if (vhost_init_device_iotlb(&n->dev, true))
1655 goto out_unlock;
1656 }
1657
1658 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) {
1659 mutex_lock(&n->vqs[i].vq.mutex);
1660 n->vqs[i].vq.acked_features = features;
1661 n->vqs[i].vhost_hlen = vhost_hlen;
1662 n->vqs[i].sock_hlen = sock_hlen;
1663 mutex_unlock(&n->vqs[i].vq.mutex);
1664 }
1665 mutex_unlock(&n->dev.mutex);
1666 return 0;
1667
1668 out_unlock:
1669 mutex_unlock(&n->dev.mutex);
1670 return -EFAULT;
1671 }
1672
1673 static long vhost_net_set_owner(struct vhost_net *n)
1674 {
1675 int r;
1676
1677 mutex_lock(&n->dev.mutex);
1678 if (vhost_dev_has_owner(&n->dev)) {
1679 r = -EBUSY;
1680 goto out;
1681 }
1682 r = vhost_net_set_ubuf_info(n);
1683 if (r)
1684 goto out;
1685 r = vhost_dev_set_owner(&n->dev);
1686 if (r)
1687 vhost_net_clear_ubuf_info(n);
1688 vhost_net_flush(n);
1689 out:
1690 mutex_unlock(&n->dev.mutex);
1691 return r;
1692 }
1693
1694 static long vhost_net_ioctl(struct file *f, unsigned int ioctl,
1695 unsigned long arg)
1696 {
1697 struct vhost_net *n = f->private_data;
1698 void __user *argp = (void __user *)arg;
1699 u64 __user *featurep = argp;
1700 struct vhost_vring_file backend;
1701 u64 features;
1702 int r;
1703
1704 switch (ioctl) {
1705 case VHOST_NET_SET_BACKEND:
1706 if (copy_from_user(&backend, argp, sizeof backend))
1707 return -EFAULT;
1708 return vhost_net_set_backend(n, backend.index, backend.fd);
1709 case VHOST_GET_FEATURES:
1710 features = VHOST_NET_FEATURES;
1711 if (copy_to_user(featurep, &features, sizeof features))
1712 return -EFAULT;
1713 return 0;
1714 case VHOST_SET_FEATURES:
1715 if (copy_from_user(&features, featurep, sizeof features))
1716 return -EFAULT;
1717 if (features & ~VHOST_NET_FEATURES)
1718 return -EOPNOTSUPP;
1719 return vhost_net_set_features(n, features);
1720 case VHOST_GET_BACKEND_FEATURES:
1721 features = VHOST_NET_BACKEND_FEATURES;
1722 if (copy_to_user(featurep, &features, sizeof(features)))
1723 return -EFAULT;
1724 return 0;
1725 case VHOST_SET_BACKEND_FEATURES:
1726 if (copy_from_user(&features, featurep, sizeof(features)))
1727 return -EFAULT;
1728 if (features & ~VHOST_NET_BACKEND_FEATURES)
1729 return -EOPNOTSUPP;
1730 return vhost_net_set_backend_features(n, features);
1731 case VHOST_RESET_OWNER:
1732 return vhost_net_reset_owner(n);
1733 case VHOST_SET_OWNER:
1734 return vhost_net_set_owner(n);
1735 default:
1736 mutex_lock(&n->dev.mutex);
1737 r = vhost_dev_ioctl(&n->dev, ioctl, argp);
1738 if (r == -ENOIOCTLCMD)
1739 r = vhost_vring_ioctl(&n->dev, ioctl, argp);
1740 else
1741 vhost_net_flush(n);
1742 mutex_unlock(&n->dev.mutex);
1743 return r;
1744 }
1745 }
1746
1747 static ssize_t vhost_net_chr_read_iter(struct kiocb *iocb, struct iov_iter *to)
1748 {
1749 struct file *file = iocb->ki_filp;
1750 struct vhost_net *n = file->private_data;
1751 struct vhost_dev *dev = &n->dev;
1752 int noblock = file->f_flags & O_NONBLOCK;
1753
1754 return vhost_chr_read_iter(dev, to, noblock);
1755 }
1756
1757 static ssize_t vhost_net_chr_write_iter(struct kiocb *iocb,
1758 struct iov_iter *from)
1759 {
1760 struct file *file = iocb->ki_filp;
1761 struct vhost_net *n = file->private_data;
1762 struct vhost_dev *dev = &n->dev;
1763
1764 return vhost_chr_write_iter(dev, from);
1765 }
1766
1767 static __poll_t vhost_net_chr_poll(struct file *file, poll_table *wait)
1768 {
1769 struct vhost_net *n = file->private_data;
1770 struct vhost_dev *dev = &n->dev;
1771
1772 return vhost_chr_poll(file, dev, wait);
1773 }
1774
1775 static const struct file_operations vhost_net_fops = {
1776 .owner = THIS_MODULE,
1777 .release = vhost_net_release,
1778 .read_iter = vhost_net_chr_read_iter,
1779 .write_iter = vhost_net_chr_write_iter,
1780 .poll = vhost_net_chr_poll,
1781 .unlocked_ioctl = vhost_net_ioctl,
1782 .compat_ioctl = compat_ptr_ioctl,
1783 .open = vhost_net_open,
1784 .llseek = noop_llseek,
1785 };
1786
1787 static struct miscdevice vhost_net_misc = {
1788 .minor = VHOST_NET_MINOR,
1789 .name = "vhost-net",
1790 .fops = &vhost_net_fops,
1791 };
1792
1793 static int vhost_net_init(void)
1794 {
1795 if (experimental_zcopytx)
1796 vhost_net_enable_zcopy(VHOST_NET_VQ_TX);
1797 return misc_register(&vhost_net_misc);
1798 }
1799 module_init(vhost_net_init);
1800
1801 static void vhost_net_exit(void)
1802 {
1803 misc_deregister(&vhost_net_misc);
1804 }
1805 module_exit(vhost_net_exit);
1806
1807 MODULE_VERSION("0.0.1");
1808 MODULE_LICENSE("GPL v2");
1809 MODULE_AUTHOR("Michael S. Tsirkin");
1810 MODULE_DESCRIPTION("Host kernel accelerator for virtio net");
1811 MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR);
1812 MODULE_ALIAS("devname:vhost-net");
Linux with added FPC-III support