1 /* Copyright (C) 2009 Red Hat, Inc. 2 * Author: Michael S. Tsirkin <mst@redhat.com> 3 * 4 * This work is licensed under the terms of the GNU GPL, version 2. 5 * 6 * virtio-net server in host kernel. 7 */ 8 9 #include <linux/compat.h> 10 #include <linux/eventfd.h> 11 #include <linux/vhost.h> 12 #include <linux/virtio_net.h> 13 #include <linux/miscdevice.h> 14 #include <linux/module.h> 15 #include <linux/moduleparam.h> 16 #include <linux/mutex.h> 17 #include <linux/workqueue.h> 18 #include <linux/file.h> 19 #include <linux/slab.h> 20 #include <linux/sched/clock.h> 21 #include <linux/sched/signal.h> 22 #include <linux/vmalloc.h> 23 24 #include <linux/net.h> 25 #include <linux/if_packet.h> 26 #include <linux/if_arp.h> 27 #include <linux/if_tun.h> 28 #include <linux/if_macvlan.h> 29 #include <linux/if_tap.h> 30 #include <linux/if_vlan.h> 31 #include <linux/skb_array.h> 32 #include <linux/skbuff.h> 33 34 #include <net/sock.h> 35 #include <net/xdp.h> 36 37 #include "vhost.h" 38 39 static int experimental_zcopytx = 1; 40 module_param(experimental_zcopytx, int, 0444); 41 MODULE_PARM_DESC(experimental_zcopytx, "Enable Zero Copy TX;" 42 " 1 -Enable; 0 - Disable"); 43 44 /* Max number of bytes transferred before requeueing the job. 45 * Using this limit prevents one virtqueue from starving others. */ 46 #define VHOST_NET_WEIGHT 0x80000 47 48 /* Max number of packets transferred before requeueing the job. 49 * Using this limit prevents one virtqueue from starving others with small 50 * pkts. 51 */ 52 #define VHOST_NET_PKT_WEIGHT 256 53 54 /* MAX number of TX used buffers for outstanding zerocopy */ 55 #define VHOST_MAX_PEND 128 56 #define VHOST_GOODCOPY_LEN 256 57 58 /* 59 * For transmit, used buffer len is unused; we override it to track buffer 60 * status internally; used for zerocopy tx only. 61 */ 62 /* Lower device DMA failed */ 63 #define VHOST_DMA_FAILED_LEN ((__force __virtio32)3) 64 /* Lower device DMA done */ 65 #define VHOST_DMA_DONE_LEN ((__force __virtio32)2) 66 /* Lower device DMA in progress */ 67 #define VHOST_DMA_IN_PROGRESS ((__force __virtio32)1) 68 /* Buffer unused */ 69 #define VHOST_DMA_CLEAR_LEN ((__force __virtio32)0) 70 71 #define VHOST_DMA_IS_DONE(len) ((__force u32)(len) >= (__force u32)VHOST_DMA_DONE_LEN) 72 73 enum { 74 VHOST_NET_FEATURES = VHOST_FEATURES | 75 (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) | 76 (1ULL << VIRTIO_NET_F_MRG_RXBUF) | 77 (1ULL << VIRTIO_F_IOMMU_PLATFORM) 78 }; 79 80 enum { 81 VHOST_NET_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2) 82 }; 83 84 enum { 85 VHOST_NET_VQ_RX = 0, 86 VHOST_NET_VQ_TX = 1, 87 VHOST_NET_VQ_MAX = 2, 88 }; 89 90 struct 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 64 102 struct vhost_net_buf { 103 void **queue; 104 int tail; 105 int head; 106 }; 107 108 struct 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 *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 }; 131 132 struct 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 }; 145 146 static unsigned vhost_net_zcopy_mask __read_mostly; 147 148 static void *vhost_net_buf_get_ptr(struct vhost_net_buf *rxq) 149 { 150 if (rxq->tail != rxq->head) 151 return rxq->queue[rxq->head]; 152 else 153 return NULL; 154 } 155 156 static int vhost_net_buf_get_size(struct vhost_net_buf *rxq) 157 { 158 return rxq->tail - rxq->head; 159 } 160 161 static int vhost_net_buf_is_empty(struct vhost_net_buf *rxq) 162 { 163 return rxq->tail == rxq->head; 164 } 165 166 static void *vhost_net_buf_consume(struct vhost_net_buf *rxq) 167 { 168 void *ret = vhost_net_buf_get_ptr(rxq); 169 ++rxq->head; 170 return ret; 171 } 172 173 static int vhost_net_buf_produce(struct vhost_net_virtqueue *nvq) 174 { 175 struct vhost_net_buf *rxq = &nvq->rxq; 176 177 rxq->head = 0; 178 rxq->tail = ptr_ring_consume_batched(nvq->rx_ring, rxq->queue, 179 VHOST_NET_BATCH); 180 return rxq->tail; 181 } 182 183 static void vhost_net_buf_unproduce(struct vhost_net_virtqueue *nvq) 184 { 185 struct vhost_net_buf *rxq = &nvq->rxq; 186 187 if (nvq->rx_ring && !vhost_net_buf_is_empty(rxq)) { 188 ptr_ring_unconsume(nvq->rx_ring, rxq->queue + rxq->head, 189 vhost_net_buf_get_size(rxq), 190 tun_ptr_free); 191 rxq->head = rxq->tail = 0; 192 } 193 } 194 195 static int vhost_net_buf_peek_len(void *ptr) 196 { 197 if (tun_is_xdp_frame(ptr)) { 198 struct xdp_frame *xdpf = tun_ptr_to_xdp(ptr); 199 200 return xdpf->len; 201 } 202 203 return __skb_array_len_with_tag(ptr); 204 } 205 206 static int vhost_net_buf_peek(struct vhost_net_virtqueue *nvq) 207 { 208 struct vhost_net_buf *rxq = &nvq->rxq; 209 210 if (!vhost_net_buf_is_empty(rxq)) 211 goto out; 212 213 if (!vhost_net_buf_produce(nvq)) 214 return 0; 215 216 out: 217 return vhost_net_buf_peek_len(vhost_net_buf_get_ptr(rxq)); 218 } 219 220 static void vhost_net_buf_init(struct vhost_net_buf *rxq) 221 { 222 rxq->head = rxq->tail = 0; 223 } 224 225 static void vhost_net_enable_zcopy(int vq) 226 { 227 vhost_net_zcopy_mask |= 0x1 << vq; 228 } 229 230 static struct vhost_net_ubuf_ref * 231 vhost_net_ubuf_alloc(struct vhost_virtqueue *vq, bool zcopy) 232 { 233 struct vhost_net_ubuf_ref *ubufs; 234 /* No zero copy backend? Nothing to count. */ 235 if (!zcopy) 236 return NULL; 237 ubufs = kmalloc(sizeof(*ubufs), GFP_KERNEL); 238 if (!ubufs) 239 return ERR_PTR(-ENOMEM); 240 atomic_set(&ubufs->refcount, 1); 241 init_waitqueue_head(&ubufs->wait); 242 ubufs->vq = vq; 243 return ubufs; 244 } 245 246 static int vhost_net_ubuf_put(struct vhost_net_ubuf_ref *ubufs) 247 { 248 int r = atomic_sub_return(1, &ubufs->refcount); 249 if (unlikely(!r)) 250 wake_up(&ubufs->wait); 251 return r; 252 } 253 254 static void vhost_net_ubuf_put_and_wait(struct vhost_net_ubuf_ref *ubufs) 255 { 256 vhost_net_ubuf_put(ubufs); 257 wait_event(ubufs->wait, !atomic_read(&ubufs->refcount)); 258 } 259 260 static void vhost_net_ubuf_put_wait_and_free(struct vhost_net_ubuf_ref *ubufs) 261 { 262 vhost_net_ubuf_put_and_wait(ubufs); 263 kfree(ubufs); 264 } 265 266 static void vhost_net_clear_ubuf_info(struct vhost_net *n) 267 { 268 int i; 269 270 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 271 kfree(n->vqs[i].ubuf_info); 272 n->vqs[i].ubuf_info = NULL; 273 } 274 } 275 276 static int vhost_net_set_ubuf_info(struct vhost_net *n) 277 { 278 bool zcopy; 279 int i; 280 281 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 282 zcopy = vhost_net_zcopy_mask & (0x1 << i); 283 if (!zcopy) 284 continue; 285 n->vqs[i].ubuf_info = 286 kmalloc_array(UIO_MAXIOV, 287 sizeof(*n->vqs[i].ubuf_info), 288 GFP_KERNEL); 289 if (!n->vqs[i].ubuf_info) 290 goto err; 291 } 292 return 0; 293 294 err: 295 vhost_net_clear_ubuf_info(n); 296 return -ENOMEM; 297 } 298 299 static void vhost_net_vq_reset(struct vhost_net *n) 300 { 301 int i; 302 303 vhost_net_clear_ubuf_info(n); 304 305 for (i = 0; i < VHOST_NET_VQ_MAX; i++) { 306 n->vqs[i].done_idx = 0; 307 n->vqs[i].upend_idx = 0; 308 n->vqs[i].ubufs = NULL; 309 n->vqs[i].vhost_hlen = 0; 310 n->vqs[i].sock_hlen = 0; 311 vhost_net_buf_init(&n->vqs[i].rxq); 312 } 313 314 } 315 316 static void vhost_net_tx_packet(struct vhost_net *net) 317 { 318 ++net->tx_packets; 319 if (net->tx_packets < 1024) 320 return; 321 net->tx_packets = 0; 322 net->tx_zcopy_err = 0; 323 } 324 325 static void vhost_net_tx_err(struct vhost_net *net) 326 { 327 ++net->tx_zcopy_err; 328 } 329 330 static bool vhost_net_tx_select_zcopy(struct vhost_net *net) 331 { 332 /* TX flush waits for outstanding DMAs to be done. 333 * Don't start new DMAs. 334 */ 335 return !net->tx_flush && 336 net->tx_packets / 64 >= net->tx_zcopy_err; 337 } 338 339 static bool vhost_sock_zcopy(struct socket *sock) 340 { 341 return unlikely(experimental_zcopytx) && 342 sock_flag(sock->sk, SOCK_ZEROCOPY); 343 } 344 345 static bool vhost_sock_xdp(struct socket *sock) 346 { 347 return sock_flag(sock->sk, SOCK_XDP); 348 } 349 350 /* In case of DMA done not in order in lower device driver for some reason. 351 * upend_idx is used to track end of used idx, done_idx is used to track head 352 * of used idx. Once lower device DMA done contiguously, we will signal KVM 353 * guest used idx. 354 */ 355 static void vhost_zerocopy_signal_used(struct vhost_net *net, 356 struct vhost_virtqueue *vq) 357 { 358 struct vhost_net_virtqueue *nvq = 359 container_of(vq, struct vhost_net_virtqueue, vq); 360 int i, add; 361 int j = 0; 362 363 for (i = nvq->done_idx; i != nvq->upend_idx; i = (i + 1) % UIO_MAXIOV) { 364 if (vq->heads[i].len == VHOST_DMA_FAILED_LEN) 365 vhost_net_tx_err(net); 366 if (VHOST_DMA_IS_DONE(vq->heads[i].len)) { 367 vq->heads[i].len = VHOST_DMA_CLEAR_LEN; 368 ++j; 369 } else 370 break; 371 } 372 while (j) { 373 add = min(UIO_MAXIOV - nvq->done_idx, j); 374 vhost_add_used_and_signal_n(vq->dev, vq, 375 &vq->heads[nvq->done_idx], add); 376 nvq->done_idx = (nvq->done_idx + add) % UIO_MAXIOV; 377 j -= add; 378 } 379 } 380 381 static void vhost_zerocopy_callback(struct ubuf_info *ubuf, bool success) 382 { 383 struct vhost_net_ubuf_ref *ubufs = ubuf->ctx; 384 struct vhost_virtqueue *vq = ubufs->vq; 385 int cnt; 386 387 rcu_read_lock_bh(); 388 389 /* set len to mark this desc buffers done DMA */ 390 vq->heads[ubuf->desc].len = success ? 391 VHOST_DMA_DONE_LEN : VHOST_DMA_FAILED_LEN; 392 cnt = vhost_net_ubuf_put(ubufs); 393 394 /* 395 * Trigger polling thread if guest stopped submitting new buffers: 396 * in this case, the refcount after decrement will eventually reach 1. 397 * We also trigger polling periodically after each 16 packets 398 * (the value 16 here is more or less arbitrary, it's tuned to trigger 399 * less than 10% of times). 400 */ 401 if (cnt <= 1 || !(cnt % 16)) 402 vhost_poll_queue(&vq->poll); 403 404 rcu_read_unlock_bh(); 405 } 406 407 static inline unsigned long busy_clock(void) 408 { 409 return local_clock() >> 10; 410 } 411 412 static bool vhost_can_busy_poll(unsigned long endtime) 413 { 414 return likely(!need_resched() && !time_after(busy_clock(), endtime) && 415 !signal_pending(current)); 416 } 417 418 static void vhost_net_disable_vq(struct vhost_net *n, 419 struct vhost_virtqueue *vq) 420 { 421 struct vhost_net_virtqueue *nvq = 422 container_of(vq, struct vhost_net_virtqueue, vq); 423 struct vhost_poll *poll = n->poll + (nvq - n->vqs); 424 if (!vq->private_data) 425 return; 426 vhost_poll_stop(poll); 427 } 428 429 static int vhost_net_enable_vq(struct vhost_net *n, 430 struct vhost_virtqueue *vq) 431 { 432 struct vhost_net_virtqueue *nvq = 433 container_of(vq, struct vhost_net_virtqueue, vq); 434 struct vhost_poll *poll = n->poll + (nvq - n->vqs); 435 struct socket *sock; 436 437 sock = vq->private_data; 438 if (!sock) 439 return 0; 440 441 return vhost_poll_start(poll, sock->file); 442 } 443 444 static void vhost_net_signal_used(struct vhost_net_virtqueue *nvq) 445 { 446 struct vhost_virtqueue *vq = &nvq->vq; 447 struct vhost_dev *dev = vq->dev; 448 449 if (!nvq->done_idx) 450 return; 451 452 vhost_add_used_and_signal_n(dev, vq, vq->heads, nvq->done_idx); 453 nvq->done_idx = 0; 454 } 455 456 static void vhost_tx_batch(struct vhost_net *net, 457 struct vhost_net_virtqueue *nvq, 458 struct socket *sock, 459 struct msghdr *msghdr) 460 { 461 struct tun_msg_ctl ctl = { 462 .type = TUN_MSG_PTR, 463 .num = nvq->batched_xdp, 464 .ptr = nvq->xdp, 465 }; 466 int err; 467 468 if (nvq->batched_xdp == 0) 469 goto signal_used; 470 471 msghdr->msg_control = &ctl; 472 err = sock->ops->sendmsg(sock, msghdr, 0); 473 if (unlikely(err < 0)) { 474 vq_err(&nvq->vq, "Fail to batch sending packets\n"); 475 return; 476 } 477 478 signal_used: 479 vhost_net_signal_used(nvq); 480 nvq->batched_xdp = 0; 481 } 482 483 static int vhost_net_tx_get_vq_desc(struct vhost_net *net, 484 struct vhost_net_virtqueue *nvq, 485 unsigned int *out_num, unsigned int *in_num, 486 struct msghdr *msghdr, bool *busyloop_intr) 487 { 488 struct vhost_virtqueue *vq = &nvq->vq; 489 unsigned long uninitialized_var(endtime); 490 int r = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov), 491 out_num, in_num, NULL, NULL); 492 493 if (r == vq->num && vq->busyloop_timeout) { 494 /* Flush batched packets first */ 495 if (!vhost_sock_zcopy(vq->private_data)) 496 vhost_tx_batch(net, nvq, vq->private_data, msghdr); 497 preempt_disable(); 498 endtime = busy_clock() + vq->busyloop_timeout; 499 while (vhost_can_busy_poll(endtime)) { 500 if (vhost_has_work(vq->dev)) { 501 *busyloop_intr = true; 502 break; 503 } 504 if (!vhost_vq_avail_empty(vq->dev, vq)) 505 break; 506 cpu_relax(); 507 } 508 preempt_enable(); 509 r = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov), 510 out_num, in_num, NULL, NULL); 511 } 512 513 return r; 514 } 515 516 static bool vhost_exceeds_maxpend(struct vhost_net *net) 517 { 518 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 519 struct vhost_virtqueue *vq = &nvq->vq; 520 521 return (nvq->upend_idx + UIO_MAXIOV - nvq->done_idx) % UIO_MAXIOV > 522 min_t(unsigned int, VHOST_MAX_PEND, vq->num >> 2); 523 } 524 525 static size_t init_iov_iter(struct vhost_virtqueue *vq, struct iov_iter *iter, 526 size_t hdr_size, int out) 527 { 528 /* Skip header. TODO: support TSO. */ 529 size_t len = iov_length(vq->iov, out); 530 531 iov_iter_init(iter, WRITE, vq->iov, out, len); 532 iov_iter_advance(iter, hdr_size); 533 534 return iov_iter_count(iter); 535 } 536 537 static bool vhost_exceeds_weight(int pkts, int total_len) 538 { 539 return total_len >= VHOST_NET_WEIGHT || 540 pkts >= VHOST_NET_PKT_WEIGHT; 541 } 542 543 static int get_tx_bufs(struct vhost_net *net, 544 struct vhost_net_virtqueue *nvq, 545 struct msghdr *msg, 546 unsigned int *out, unsigned int *in, 547 size_t *len, bool *busyloop_intr) 548 { 549 struct vhost_virtqueue *vq = &nvq->vq; 550 int ret; 551 552 ret = vhost_net_tx_get_vq_desc(net, nvq, out, in, msg, busyloop_intr); 553 554 if (ret < 0 || ret == vq->num) 555 return ret; 556 557 if (*in) { 558 vq_err(vq, "Unexpected descriptor format for TX: out %d, int %d\n", 559 *out, *in); 560 return -EFAULT; 561 } 562 563 /* Sanity check */ 564 *len = init_iov_iter(vq, &msg->msg_iter, nvq->vhost_hlen, *out); 565 if (*len == 0) { 566 vq_err(vq, "Unexpected header len for TX: %zd expected %zd\n", 567 *len, nvq->vhost_hlen); 568 return -EFAULT; 569 } 570 571 return ret; 572 } 573 574 static bool tx_can_batch(struct vhost_virtqueue *vq, size_t total_len) 575 { 576 return total_len < VHOST_NET_WEIGHT && 577 !vhost_vq_avail_empty(vq->dev, vq); 578 } 579 580 #define VHOST_NET_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD) 581 582 static int vhost_net_build_xdp(struct vhost_net_virtqueue *nvq, 583 struct iov_iter *from) 584 { 585 struct vhost_virtqueue *vq = &nvq->vq; 586 struct socket *sock = vq->private_data; 587 struct page_frag *alloc_frag = ¤t->task_frag; 588 struct virtio_net_hdr *gso; 589 struct xdp_buff *xdp = &nvq->xdp[nvq->batched_xdp]; 590 struct tun_xdp_hdr *hdr; 591 size_t len = iov_iter_count(from); 592 int headroom = vhost_sock_xdp(sock) ? XDP_PACKET_HEADROOM : 0; 593 int buflen = SKB_DATA_ALIGN(sizeof(struct skb_shared_info)); 594 int pad = SKB_DATA_ALIGN(VHOST_NET_RX_PAD + headroom + nvq->sock_hlen); 595 int sock_hlen = nvq->sock_hlen; 596 void *buf; 597 int copied; 598 599 if (unlikely(len < nvq->sock_hlen)) 600 return -EFAULT; 601 602 if (SKB_DATA_ALIGN(len + pad) + 603 SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) > PAGE_SIZE) 604 return -ENOSPC; 605 606 buflen += SKB_DATA_ALIGN(len + pad); 607 alloc_frag->offset = ALIGN((u64)alloc_frag->offset, SMP_CACHE_BYTES); 608 if (unlikely(!skb_page_frag_refill(buflen, alloc_frag, GFP_KERNEL))) 609 return -ENOMEM; 610 611 buf = (char *)page_address(alloc_frag->page) + alloc_frag->offset; 612 copied = copy_page_from_iter(alloc_frag->page, 613 alloc_frag->offset + 614 offsetof(struct tun_xdp_hdr, gso), 615 sock_hlen, from); 616 if (copied != sock_hlen) 617 return -EFAULT; 618 619 hdr = buf; 620 gso = &hdr->gso; 621 622 if ((gso->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) && 623 vhost16_to_cpu(vq, gso->csum_start) + 624 vhost16_to_cpu(vq, gso->csum_offset) + 2 > 625 vhost16_to_cpu(vq, gso->hdr_len)) { 626 gso->hdr_len = cpu_to_vhost16(vq, 627 vhost16_to_cpu(vq, gso->csum_start) + 628 vhost16_to_cpu(vq, gso->csum_offset) + 2); 629 630 if (vhost16_to_cpu(vq, gso->hdr_len) > len) 631 return -EINVAL; 632 } 633 634 len -= sock_hlen; 635 copied = copy_page_from_iter(alloc_frag->page, 636 alloc_frag->offset + pad, 637 len, from); 638 if (copied != len) 639 return -EFAULT; 640 641 xdp->data_hard_start = buf; 642 xdp->data = buf + pad; 643 xdp->data_end = xdp->data + len; 644 hdr->buflen = buflen; 645 646 get_page(alloc_frag->page); 647 alloc_frag->offset += buflen; 648 649 ++nvq->batched_xdp; 650 651 return 0; 652 } 653 654 static void handle_tx_copy(struct vhost_net *net, struct socket *sock) 655 { 656 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 657 struct vhost_virtqueue *vq = &nvq->vq; 658 unsigned out, in; 659 int head; 660 struct msghdr msg = { 661 .msg_name = NULL, 662 .msg_namelen = 0, 663 .msg_control = NULL, 664 .msg_controllen = 0, 665 .msg_flags = MSG_DONTWAIT, 666 }; 667 size_t len, total_len = 0; 668 int err; 669 int sent_pkts = 0; 670 bool sock_can_batch = (sock->sk->sk_sndbuf == INT_MAX); 671 672 for (;;) { 673 bool busyloop_intr = false; 674 675 if (nvq->done_idx == VHOST_NET_BATCH) 676 vhost_tx_batch(net, nvq, sock, &msg); 677 678 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len, 679 &busyloop_intr); 680 /* On error, stop handling until the next kick. */ 681 if (unlikely(head < 0)) 682 break; 683 /* Nothing new? Wait for eventfd to tell us they refilled. */ 684 if (head == vq->num) { 685 if (unlikely(busyloop_intr)) { 686 vhost_poll_queue(&vq->poll); 687 } else if (unlikely(vhost_enable_notify(&net->dev, 688 vq))) { 689 vhost_disable_notify(&net->dev, vq); 690 continue; 691 } 692 break; 693 } 694 695 total_len += len; 696 697 /* For simplicity, TX batching is only enabled if 698 * sndbuf is unlimited. 699 */ 700 if (sock_can_batch) { 701 err = vhost_net_build_xdp(nvq, &msg.msg_iter); 702 if (!err) { 703 goto done; 704 } else if (unlikely(err != -ENOSPC)) { 705 vhost_tx_batch(net, nvq, sock, &msg); 706 vhost_discard_vq_desc(vq, 1); 707 vhost_net_enable_vq(net, vq); 708 break; 709 } 710 711 /* We can't build XDP buff, go for single 712 * packet path but let's flush batched 713 * packets. 714 */ 715 vhost_tx_batch(net, nvq, sock, &msg); 716 msg.msg_control = NULL; 717 } else { 718 if (tx_can_batch(vq, total_len)) 719 msg.msg_flags |= MSG_MORE; 720 else 721 msg.msg_flags &= ~MSG_MORE; 722 } 723 724 /* TODO: Check specific error and bomb out unless ENOBUFS? */ 725 err = sock->ops->sendmsg(sock, &msg, len); 726 if (unlikely(err < 0)) { 727 vhost_discard_vq_desc(vq, 1); 728 vhost_net_enable_vq(net, vq); 729 break; 730 } 731 if (err != len) 732 pr_debug("Truncated TX packet: len %d != %zd\n", 733 err, len); 734 done: 735 vq->heads[nvq->done_idx].id = cpu_to_vhost32(vq, head); 736 vq->heads[nvq->done_idx].len = 0; 737 ++nvq->done_idx; 738 if (vhost_exceeds_weight(++sent_pkts, total_len)) { 739 vhost_poll_queue(&vq->poll); 740 break; 741 } 742 } 743 744 vhost_tx_batch(net, nvq, sock, &msg); 745 } 746 747 static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) 748 { 749 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 750 struct vhost_virtqueue *vq = &nvq->vq; 751 unsigned out, in; 752 int head; 753 struct msghdr msg = { 754 .msg_name = NULL, 755 .msg_namelen = 0, 756 .msg_control = NULL, 757 .msg_controllen = 0, 758 .msg_flags = MSG_DONTWAIT, 759 }; 760 struct tun_msg_ctl ctl; 761 size_t len, total_len = 0; 762 int err; 763 struct vhost_net_ubuf_ref *uninitialized_var(ubufs); 764 bool zcopy_used; 765 int sent_pkts = 0; 766 767 for (;;) { 768 bool busyloop_intr; 769 770 /* Release DMAs done buffers first */ 771 vhost_zerocopy_signal_used(net, vq); 772 773 busyloop_intr = false; 774 head = get_tx_bufs(net, nvq, &msg, &out, &in, &len, 775 &busyloop_intr); 776 /* On error, stop handling until the next kick. */ 777 if (unlikely(head < 0)) 778 break; 779 /* Nothing new? Wait for eventfd to tell us they refilled. */ 780 if (head == vq->num) { 781 if (unlikely(busyloop_intr)) { 782 vhost_poll_queue(&vq->poll); 783 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { 784 vhost_disable_notify(&net->dev, vq); 785 continue; 786 } 787 break; 788 } 789 790 zcopy_used = len >= VHOST_GOODCOPY_LEN 791 && !vhost_exceeds_maxpend(net) 792 && vhost_net_tx_select_zcopy(net); 793 794 /* use msg_control to pass vhost zerocopy ubuf info to skb */ 795 if (zcopy_used) { 796 struct ubuf_info *ubuf; 797 ubuf = nvq->ubuf_info + nvq->upend_idx; 798 799 vq->heads[nvq->upend_idx].id = cpu_to_vhost32(vq, head); 800 vq->heads[nvq->upend_idx].len = VHOST_DMA_IN_PROGRESS; 801 ubuf->callback = vhost_zerocopy_callback; 802 ubuf->ctx = nvq->ubufs; 803 ubuf->desc = nvq->upend_idx; 804 refcount_set(&ubuf->refcnt, 1); 805 msg.msg_control = &ctl; 806 ctl.type = TUN_MSG_UBUF; 807 ctl.ptr = ubuf; 808 msg.msg_controllen = sizeof(ctl); 809 ubufs = nvq->ubufs; 810 atomic_inc(&ubufs->refcount); 811 nvq->upend_idx = (nvq->upend_idx + 1) % UIO_MAXIOV; 812 } else { 813 msg.msg_control = NULL; 814 ubufs = NULL; 815 } 816 total_len += len; 817 if (tx_can_batch(vq, total_len) && 818 likely(!vhost_exceeds_maxpend(net))) { 819 msg.msg_flags |= MSG_MORE; 820 } else { 821 msg.msg_flags &= ~MSG_MORE; 822 } 823 824 /* TODO: Check specific error and bomb out unless ENOBUFS? */ 825 err = sock->ops->sendmsg(sock, &msg, len); 826 if (unlikely(err < 0)) { 827 if (zcopy_used) { 828 vhost_net_ubuf_put(ubufs); 829 nvq->upend_idx = ((unsigned)nvq->upend_idx - 1) 830 % UIO_MAXIOV; 831 } 832 vhost_discard_vq_desc(vq, 1); 833 vhost_net_enable_vq(net, vq); 834 break; 835 } 836 if (err != len) 837 pr_debug("Truncated TX packet: " 838 " len %d != %zd\n", err, len); 839 if (!zcopy_used) 840 vhost_add_used_and_signal(&net->dev, vq, head, 0); 841 else 842 vhost_zerocopy_signal_used(net, vq); 843 vhost_net_tx_packet(net); 844 if (unlikely(vhost_exceeds_weight(++sent_pkts, total_len))) { 845 vhost_poll_queue(&vq->poll); 846 break; 847 } 848 } 849 } 850 851 /* Expects to be always run from workqueue - which acts as 852 * read-size critical section for our kind of RCU. */ 853 static void handle_tx(struct vhost_net *net) 854 { 855 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_TX]; 856 struct vhost_virtqueue *vq = &nvq->vq; 857 struct socket *sock; 858 859 mutex_lock(&vq->mutex); 860 sock = vq->private_data; 861 if (!sock) 862 goto out; 863 864 if (!vq_iotlb_prefetch(vq)) 865 goto out; 866 867 vhost_disable_notify(&net->dev, vq); 868 vhost_net_disable_vq(net, vq); 869 870 if (vhost_sock_zcopy(sock)) 871 handle_tx_zerocopy(net, sock); 872 else 873 handle_tx_copy(net, sock); 874 875 out: 876 mutex_unlock(&vq->mutex); 877 } 878 879 static int peek_head_len(struct vhost_net_virtqueue *rvq, struct sock *sk) 880 { 881 struct sk_buff *head; 882 int len = 0; 883 unsigned long flags; 884 885 if (rvq->rx_ring) 886 return vhost_net_buf_peek(rvq); 887 888 spin_lock_irqsave(&sk->sk_receive_queue.lock, flags); 889 head = skb_peek(&sk->sk_receive_queue); 890 if (likely(head)) { 891 len = head->len; 892 if (skb_vlan_tag_present(head)) 893 len += VLAN_HLEN; 894 } 895 896 spin_unlock_irqrestore(&sk->sk_receive_queue.lock, flags); 897 return len; 898 } 899 900 static int sk_has_rx_data(struct sock *sk) 901 { 902 struct socket *sock = sk->sk_socket; 903 904 if (sock->ops->peek_len) 905 return sock->ops->peek_len(sock); 906 907 return skb_queue_empty(&sk->sk_receive_queue); 908 } 909 910 static int vhost_net_rx_peek_head_len(struct vhost_net *net, struct sock *sk, 911 bool *busyloop_intr) 912 { 913 struct vhost_net_virtqueue *rnvq = &net->vqs[VHOST_NET_VQ_RX]; 914 struct vhost_net_virtqueue *tnvq = &net->vqs[VHOST_NET_VQ_TX]; 915 struct vhost_virtqueue *rvq = &rnvq->vq; 916 struct vhost_virtqueue *tvq = &tnvq->vq; 917 unsigned long uninitialized_var(endtime); 918 int len = peek_head_len(rnvq, sk); 919 920 if (!len && tvq->busyloop_timeout) { 921 /* Flush batched heads first */ 922 vhost_net_signal_used(rnvq); 923 /* Both tx vq and rx socket were polled here */ 924 mutex_lock_nested(&tvq->mutex, 1); 925 vhost_disable_notify(&net->dev, tvq); 926 927 preempt_disable(); 928 endtime = busy_clock() + tvq->busyloop_timeout; 929 930 while (vhost_can_busy_poll(endtime)) { 931 if (vhost_has_work(&net->dev)) { 932 *busyloop_intr = true; 933 break; 934 } 935 if ((sk_has_rx_data(sk) && 936 !vhost_vq_avail_empty(&net->dev, rvq)) || 937 !vhost_vq_avail_empty(&net->dev, tvq)) 938 break; 939 cpu_relax(); 940 } 941 942 preempt_enable(); 943 944 if (!vhost_vq_avail_empty(&net->dev, tvq)) { 945 vhost_poll_queue(&tvq->poll); 946 } else if (unlikely(vhost_enable_notify(&net->dev, tvq))) { 947 vhost_disable_notify(&net->dev, tvq); 948 vhost_poll_queue(&tvq->poll); 949 } 950 951 mutex_unlock(&tvq->mutex); 952 953 len = peek_head_len(rnvq, sk); 954 } 955 956 return len; 957 } 958 959 /* This is a multi-buffer version of vhost_get_desc, that works if 960 * vq has read descriptors only. 961 * @vq - the relevant virtqueue 962 * @datalen - data length we'll be reading 963 * @iovcount - returned count of io vectors we fill 964 * @log - vhost log 965 * @log_num - log offset 966 * @quota - headcount quota, 1 for big buffer 967 * returns number of buffer heads allocated, negative on error 968 */ 969 static int get_rx_bufs(struct vhost_virtqueue *vq, 970 struct vring_used_elem *heads, 971 int datalen, 972 unsigned *iovcount, 973 struct vhost_log *log, 974 unsigned *log_num, 975 unsigned int quota) 976 { 977 unsigned int out, in; 978 int seg = 0; 979 int headcount = 0; 980 unsigned d; 981 int r, nlogs = 0; 982 /* len is always initialized before use since we are always called with 983 * datalen > 0. 984 */ 985 u32 uninitialized_var(len); 986 987 while (datalen > 0 && headcount < quota) { 988 if (unlikely(seg >= UIO_MAXIOV)) { 989 r = -ENOBUFS; 990 goto err; 991 } 992 r = vhost_get_vq_desc(vq, vq->iov + seg, 993 ARRAY_SIZE(vq->iov) - seg, &out, 994 &in, log, log_num); 995 if (unlikely(r < 0)) 996 goto err; 997 998 d = r; 999 if (d == vq->num) { 1000 r = 0; 1001 goto err; 1002 } 1003 if (unlikely(out || in <= 0)) { 1004 vq_err(vq, "unexpected descriptor format for RX: " 1005 "out %d, in %d\n", out, in); 1006 r = -EINVAL; 1007 goto err; 1008 } 1009 if (unlikely(log)) { 1010 nlogs += *log_num; 1011 log += *log_num; 1012 } 1013 heads[headcount].id = cpu_to_vhost32(vq, d); 1014 len = iov_length(vq->iov + seg, in); 1015 heads[headcount].len = cpu_to_vhost32(vq, len); 1016 datalen -= len; 1017 ++headcount; 1018 seg += in; 1019 } 1020 heads[headcount - 1].len = cpu_to_vhost32(vq, len + datalen); 1021 *iovcount = seg; 1022 if (unlikely(log)) 1023 *log_num = nlogs; 1024 1025 /* Detect overrun */ 1026 if (unlikely(datalen > 0)) { 1027 r = UIO_MAXIOV + 1; 1028 goto err; 1029 } 1030 return headcount; 1031 err: 1032 vhost_discard_vq_desc(vq, headcount); 1033 return r; 1034 } 1035 1036 /* Expects to be always run from workqueue - which acts as 1037 * read-size critical section for our kind of RCU. */ 1038 static void handle_rx(struct vhost_net *net) 1039 { 1040 struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_RX]; 1041 struct vhost_virtqueue *vq = &nvq->vq; 1042 unsigned uninitialized_var(in), log; 1043 struct vhost_log *vq_log; 1044 struct msghdr msg = { 1045 .msg_name = NULL, 1046 .msg_namelen = 0, 1047 .msg_control = NULL, /* FIXME: get and handle RX aux data. */ 1048 .msg_controllen = 0, 1049 .msg_flags = MSG_DONTWAIT, 1050 }; 1051 struct virtio_net_hdr hdr = { 1052 .flags = 0, 1053 .gso_type = VIRTIO_NET_HDR_GSO_NONE 1054 }; 1055 size_t total_len = 0; 1056 int err, mergeable; 1057 s16 headcount; 1058 size_t vhost_hlen, sock_hlen; 1059 size_t vhost_len, sock_len; 1060 bool busyloop_intr = false; 1061 struct socket *sock; 1062 struct iov_iter fixup; 1063 __virtio16 num_buffers; 1064 int recv_pkts = 0; 1065 1066 mutex_lock_nested(&vq->mutex, 0); 1067 sock = vq->private_data; 1068 if (!sock) 1069 goto out; 1070 1071 if (!vq_iotlb_prefetch(vq)) 1072 goto out; 1073 1074 vhost_disable_notify(&net->dev, vq); 1075 vhost_net_disable_vq(net, vq); 1076 1077 vhost_hlen = nvq->vhost_hlen; 1078 sock_hlen = nvq->sock_hlen; 1079 1080 vq_log = unlikely(vhost_has_feature(vq, VHOST_F_LOG_ALL)) ? 1081 vq->log : NULL; 1082 mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF); 1083 1084 while ((sock_len = vhost_net_rx_peek_head_len(net, sock->sk, 1085 &busyloop_intr))) { 1086 sock_len += sock_hlen; 1087 vhost_len = sock_len + vhost_hlen; 1088 headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx, 1089 vhost_len, &in, vq_log, &log, 1090 likely(mergeable) ? UIO_MAXIOV : 1); 1091 /* On error, stop handling until the next kick. */ 1092 if (unlikely(headcount < 0)) 1093 goto out; 1094 /* OK, now we need to know about added descriptors. */ 1095 if (!headcount) { 1096 if (unlikely(busyloop_intr)) { 1097 vhost_poll_queue(&vq->poll); 1098 } else if (unlikely(vhost_enable_notify(&net->dev, vq))) { 1099 /* They have slipped one in as we were 1100 * doing that: check again. */ 1101 vhost_disable_notify(&net->dev, vq); 1102 continue; 1103 } 1104 /* Nothing new? Wait for eventfd to tell us 1105 * they refilled. */ 1106 goto out; 1107 } 1108 busyloop_intr = false; 1109 if (nvq->rx_ring) 1110 msg.msg_control = vhost_net_buf_consume(&nvq->rxq); 1111 /* On overrun, truncate and discard */ 1112 if (unlikely(headcount > UIO_MAXIOV)) { 1113 iov_iter_init(&msg.msg_iter, READ, vq->iov, 1, 1); 1114 err = sock->ops->recvmsg(sock, &msg, 1115 1, MSG_DONTWAIT | MSG_TRUNC); 1116 pr_debug("Discarded rx packet: len %zd\n", sock_len); 1117 continue; 1118 } 1119 /* We don't need to be notified again. */ 1120 iov_iter_init(&msg.msg_iter, READ, vq->iov, in, vhost_len); 1121 fixup = msg.msg_iter; 1122 if (unlikely((vhost_hlen))) { 1123 /* We will supply the header ourselves 1124 * TODO: support TSO. 1125 */ 1126 iov_iter_advance(&msg.msg_iter, vhost_hlen); 1127 } 1128 err = sock->ops->recvmsg(sock, &msg, 1129 sock_len, MSG_DONTWAIT | MSG_TRUNC); 1130 /* Userspace might have consumed the packet meanwhile: 1131 * it's not supposed to do this usually, but might be hard 1132 * to prevent. Discard data we got (if any) and keep going. */ 1133 if (unlikely(err != sock_len)) { 1134 pr_debug("Discarded rx packet: " 1135 " len %d, expected %zd\n", err, sock_len); 1136 vhost_discard_vq_desc(vq, headcount); 1137 continue; 1138 } 1139 /* Supply virtio_net_hdr if VHOST_NET_F_VIRTIO_NET_HDR */ 1140 if (unlikely(vhost_hlen)) { 1141 if (copy_to_iter(&hdr, sizeof(hdr), 1142 &fixup) != sizeof(hdr)) { 1143 vq_err(vq, "Unable to write vnet_hdr " 1144 "at addr %p\n", vq->iov->iov_base); 1145 goto out; 1146 } 1147 } else { 1148 /* Header came from socket; we'll need to patch 1149 * ->num_buffers over if VIRTIO_NET_F_MRG_RXBUF 1150 */ 1151 iov_iter_advance(&fixup, sizeof(hdr)); 1152 } 1153 /* TODO: Should check and handle checksum. */ 1154 1155 num_buffers = cpu_to_vhost16(vq, headcount); 1156 if (likely(mergeable) && 1157 copy_to_iter(&num_buffers, sizeof num_buffers, 1158 &fixup) != sizeof num_buffers) { 1159 vq_err(vq, "Failed num_buffers write"); 1160 vhost_discard_vq_desc(vq, headcount); 1161 goto out; 1162 } 1163 nvq->done_idx += headcount; 1164 if (nvq->done_idx > VHOST_NET_BATCH) 1165 vhost_net_signal_used(nvq); 1166 if (unlikely(vq_log)) 1167 vhost_log_write(vq, vq_log, log, vhost_len); 1168 total_len += vhost_len; 1169 if (unlikely(vhost_exceeds_weight(++recv_pkts, total_len))) { 1170 vhost_poll_queue(&vq->poll); 1171 goto out; 1172 } 1173 } 1174 if (unlikely(busyloop_intr)) 1175 vhost_poll_queue(&vq->poll); 1176 else 1177 vhost_net_enable_vq(net, vq); 1178 out: 1179 vhost_net_signal_used(nvq); 1180 mutex_unlock(&vq->mutex); 1181 } 1182 1183 static void handle_tx_kick(struct vhost_work *work) 1184 { 1185 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 1186 poll.work); 1187 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 1188 1189 handle_tx(net); 1190 } 1191 1192 static void handle_rx_kick(struct vhost_work *work) 1193 { 1194 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 1195 poll.work); 1196 struct vhost_net *net = container_of(vq->dev, struct vhost_net, dev); 1197 1198 handle_rx(net); 1199 } 1200 1201 static void handle_tx_net(struct vhost_work *work) 1202 { 1203 struct vhost_net *net = container_of(work, struct vhost_net, 1204 poll[VHOST_NET_VQ_TX].work); 1205 handle_tx(net); 1206 } 1207 1208 static void handle_rx_net(struct vhost_work *work) 1209 { 1210 struct vhost_net *net = container_of(work, struct vhost_net, 1211 poll[VHOST_NET_VQ_RX].work); 1212 handle_rx(net); 1213 } 1214 1215 static int vhost_net_open(struct inode *inode, struct file *f) 1216 { 1217 struct vhost_net *n; 1218 struct vhost_dev *dev; 1219 struct vhost_virtqueue **vqs; 1220 void **queue; 1221 struct xdp_buff *xdp; 1222 int i; 1223 1224 n = kvmalloc(sizeof *n, GFP_KERNEL | __GFP_RETRY_MAYFAIL); 1225 if (!n) 1226 return -ENOMEM; 1227 vqs = kmalloc_array(VHOST_NET_VQ_MAX, sizeof(*vqs), GFP_KERNEL); 1228 if (!vqs) { 1229 kvfree(n); 1230 return -ENOMEM; 1231 } 1232 1233 queue = kmalloc_array(VHOST_NET_BATCH, sizeof(void *), 1234 GFP_KERNEL); 1235 if (!queue) { 1236 kfree(vqs); 1237 kvfree(n); 1238 return -ENOMEM; 1239 } 1240 n->vqs[VHOST_NET_VQ_RX].rxq.queue = queue; 1241 1242 xdp = kmalloc_array(VHOST_NET_BATCH, sizeof(*xdp), GFP_KERNEL); 1243 if (!xdp) { 1244 kfree(vqs); 1245 kvfree(n); 1246 kfree(queue); 1247 } 1248 n->vqs[VHOST_NET_VQ_TX].xdp = xdp; 1249 1250 dev = &n->dev; 1251 vqs[VHOST_NET_VQ_TX] = &n->vqs[VHOST_NET_VQ_TX].vq; 1252 vqs[VHOST_NET_VQ_RX] = &n->vqs[VHOST_NET_VQ_RX].vq; 1253 n->vqs[VHOST_NET_VQ_TX].vq.handle_kick = handle_tx_kick; 1254 n->vqs[VHOST_NET_VQ_RX].vq.handle_kick = handle_rx_kick; 1255 for (i = 0; i < VHOST_NET_VQ_MAX; i++) { 1256 n->vqs[i].ubufs = NULL; 1257 n->vqs[i].ubuf_info = NULL; 1258 n->vqs[i].upend_idx = 0; 1259 n->vqs[i].done_idx = 0; 1260 n->vqs[i].batched_xdp = 0; 1261 n->vqs[i].vhost_hlen = 0; 1262 n->vqs[i].sock_hlen = 0; 1263 n->vqs[i].rx_ring = NULL; 1264 vhost_net_buf_init(&n->vqs[i].rxq); 1265 } 1266 vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX); 1267 1268 vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, EPOLLOUT, dev); 1269 vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, EPOLLIN, dev); 1270 1271 f->private_data = n; 1272 1273 return 0; 1274 } 1275 1276 static struct socket *vhost_net_stop_vq(struct vhost_net *n, 1277 struct vhost_virtqueue *vq) 1278 { 1279 struct socket *sock; 1280 struct vhost_net_virtqueue *nvq = 1281 container_of(vq, struct vhost_net_virtqueue, vq); 1282 1283 mutex_lock(&vq->mutex); 1284 sock = vq->private_data; 1285 vhost_net_disable_vq(n, vq); 1286 vq->private_data = NULL; 1287 vhost_net_buf_unproduce(nvq); 1288 nvq->rx_ring = NULL; 1289 mutex_unlock(&vq->mutex); 1290 return sock; 1291 } 1292 1293 static void vhost_net_stop(struct vhost_net *n, struct socket **tx_sock, 1294 struct socket **rx_sock) 1295 { 1296 *tx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_TX].vq); 1297 *rx_sock = vhost_net_stop_vq(n, &n->vqs[VHOST_NET_VQ_RX].vq); 1298 } 1299 1300 static void vhost_net_flush_vq(struct vhost_net *n, int index) 1301 { 1302 vhost_poll_flush(n->poll + index); 1303 vhost_poll_flush(&n->vqs[index].vq.poll); 1304 } 1305 1306 static void vhost_net_flush(struct vhost_net *n) 1307 { 1308 vhost_net_flush_vq(n, VHOST_NET_VQ_TX); 1309 vhost_net_flush_vq(n, VHOST_NET_VQ_RX); 1310 if (n->vqs[VHOST_NET_VQ_TX].ubufs) { 1311 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1312 n->tx_flush = true; 1313 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1314 /* Wait for all lower device DMAs done. */ 1315 vhost_net_ubuf_put_and_wait(n->vqs[VHOST_NET_VQ_TX].ubufs); 1316 mutex_lock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1317 n->tx_flush = false; 1318 atomic_set(&n->vqs[VHOST_NET_VQ_TX].ubufs->refcount, 1); 1319 mutex_unlock(&n->vqs[VHOST_NET_VQ_TX].vq.mutex); 1320 } 1321 } 1322 1323 static int vhost_net_release(struct inode *inode, struct file *f) 1324 { 1325 struct vhost_net *n = f->private_data; 1326 struct socket *tx_sock; 1327 struct socket *rx_sock; 1328 1329 vhost_net_stop(n, &tx_sock, &rx_sock); 1330 vhost_net_flush(n); 1331 vhost_dev_stop(&n->dev); 1332 vhost_dev_cleanup(&n->dev); 1333 vhost_net_vq_reset(n); 1334 if (tx_sock) 1335 sockfd_put(tx_sock); 1336 if (rx_sock) 1337 sockfd_put(rx_sock); 1338 /* Make sure no callbacks are outstanding */ 1339 synchronize_rcu_bh(); 1340 /* We do an extra flush before freeing memory, 1341 * since jobs can re-queue themselves. */ 1342 vhost_net_flush(n); 1343 kfree(n->vqs[VHOST_NET_VQ_RX].rxq.queue); 1344 kfree(n->vqs[VHOST_NET_VQ_TX].xdp); 1345 kfree(n->dev.vqs); 1346 kvfree(n); 1347 return 0; 1348 } 1349 1350 static struct socket *get_raw_socket(int fd) 1351 { 1352 struct { 1353 struct sockaddr_ll sa; 1354 char buf[MAX_ADDR_LEN]; 1355 } uaddr; 1356 int r; 1357 struct socket *sock = sockfd_lookup(fd, &r); 1358 1359 if (!sock) 1360 return ERR_PTR(-ENOTSOCK); 1361 1362 /* Parameter checking */ 1363 if (sock->sk->sk_type != SOCK_RAW) { 1364 r = -ESOCKTNOSUPPORT; 1365 goto err; 1366 } 1367 1368 r = sock->ops->getname(sock, (struct sockaddr *)&uaddr.sa, 0); 1369 if (r < 0) 1370 goto err; 1371 1372 if (uaddr.sa.sll_family != AF_PACKET) { 1373 r = -EPFNOSUPPORT; 1374 goto err; 1375 } 1376 return sock; 1377 err: 1378 sockfd_put(sock); 1379 return ERR_PTR(r); 1380 } 1381 1382 static struct ptr_ring *get_tap_ptr_ring(int fd) 1383 { 1384 struct ptr_ring *ring; 1385 struct file *file = fget(fd); 1386 1387 if (!file) 1388 return NULL; 1389 ring = tun_get_tx_ring(file); 1390 if (!IS_ERR(ring)) 1391 goto out; 1392 ring = tap_get_ptr_ring(file); 1393 if (!IS_ERR(ring)) 1394 goto out; 1395 ring = NULL; 1396 out: 1397 fput(file); 1398 return ring; 1399 } 1400 1401 static struct socket *get_tap_socket(int fd) 1402 { 1403 struct file *file = fget(fd); 1404 struct socket *sock; 1405 1406 if (!file) 1407 return ERR_PTR(-EBADF); 1408 sock = tun_get_socket(file); 1409 if (!IS_ERR(sock)) 1410 return sock; 1411 sock = tap_get_socket(file); 1412 if (IS_ERR(sock)) 1413 fput(file); 1414 return sock; 1415 } 1416 1417 static struct socket *get_socket(int fd) 1418 { 1419 struct socket *sock; 1420 1421 /* special case to disable backend */ 1422 if (fd == -1) 1423 return NULL; 1424 sock = get_raw_socket(fd); 1425 if (!IS_ERR(sock)) 1426 return sock; 1427 sock = get_tap_socket(fd); 1428 if (!IS_ERR(sock)) 1429 return sock; 1430 return ERR_PTR(-ENOTSOCK); 1431 } 1432 1433 static long vhost_net_set_backend(struct vhost_net *n, unsigned index, int fd) 1434 { 1435 struct socket *sock, *oldsock; 1436 struct vhost_virtqueue *vq; 1437 struct vhost_net_virtqueue *nvq; 1438 struct vhost_net_ubuf_ref *ubufs, *oldubufs = NULL; 1439 int r; 1440 1441 mutex_lock(&n->dev.mutex); 1442 r = vhost_dev_check_owner(&n->dev); 1443 if (r) 1444 goto err; 1445 1446 if (index >= VHOST_NET_VQ_MAX) { 1447 r = -ENOBUFS; 1448 goto err; 1449 } 1450 vq = &n->vqs[index].vq; 1451 nvq = &n->vqs[index]; 1452 mutex_lock(&vq->mutex); 1453 1454 /* Verify that ring has been setup correctly. */ 1455 if (!vhost_vq_access_ok(vq)) { 1456 r = -EFAULT; 1457 goto err_vq; 1458 } 1459 sock = get_socket(fd); 1460 if (IS_ERR(sock)) { 1461 r = PTR_ERR(sock); 1462 goto err_vq; 1463 } 1464 1465 /* start polling new socket */ 1466 oldsock = vq->private_data; 1467 if (sock != oldsock) { 1468 ubufs = vhost_net_ubuf_alloc(vq, 1469 sock && vhost_sock_zcopy(sock)); 1470 if (IS_ERR(ubufs)) { 1471 r = PTR_ERR(ubufs); 1472 goto err_ubufs; 1473 } 1474 1475 vhost_net_disable_vq(n, vq); 1476 vq->private_data = sock; 1477 vhost_net_buf_unproduce(nvq); 1478 r = vhost_vq_init_access(vq); 1479 if (r) 1480 goto err_used; 1481 r = vhost_net_enable_vq(n, vq); 1482 if (r) 1483 goto err_used; 1484 if (index == VHOST_NET_VQ_RX) 1485 nvq->rx_ring = get_tap_ptr_ring(fd); 1486 1487 oldubufs = nvq->ubufs; 1488 nvq->ubufs = ubufs; 1489 1490 n->tx_packets = 0; 1491 n->tx_zcopy_err = 0; 1492 n->tx_flush = false; 1493 } 1494 1495 mutex_unlock(&vq->mutex); 1496 1497 if (oldubufs) { 1498 vhost_net_ubuf_put_wait_and_free(oldubufs); 1499 mutex_lock(&vq->mutex); 1500 vhost_zerocopy_signal_used(n, vq); 1501 mutex_unlock(&vq->mutex); 1502 } 1503 1504 if (oldsock) { 1505 vhost_net_flush_vq(n, index); 1506 sockfd_put(oldsock); 1507 } 1508 1509 mutex_unlock(&n->dev.mutex); 1510 return 0; 1511 1512 err_used: 1513 vq->private_data = oldsock; 1514 vhost_net_enable_vq(n, vq); 1515 if (ubufs) 1516 vhost_net_ubuf_put_wait_and_free(ubufs); 1517 err_ubufs: 1518 if (sock) 1519 sockfd_put(sock); 1520 err_vq: 1521 mutex_unlock(&vq->mutex); 1522 err: 1523 mutex_unlock(&n->dev.mutex); 1524 return r; 1525 } 1526 1527 static long vhost_net_reset_owner(struct vhost_net *n) 1528 { 1529 struct socket *tx_sock = NULL; 1530 struct socket *rx_sock = NULL; 1531 long err; 1532 struct vhost_umem *umem; 1533 1534 mutex_lock(&n->dev.mutex); 1535 err = vhost_dev_check_owner(&n->dev); 1536 if (err) 1537 goto done; 1538 umem = vhost_dev_reset_owner_prepare(); 1539 if (!umem) { 1540 err = -ENOMEM; 1541 goto done; 1542 } 1543 vhost_net_stop(n, &tx_sock, &rx_sock); 1544 vhost_net_flush(n); 1545 vhost_dev_stop(&n->dev); 1546 vhost_dev_reset_owner(&n->dev, umem); 1547 vhost_net_vq_reset(n); 1548 done: 1549 mutex_unlock(&n->dev.mutex); 1550 if (tx_sock) 1551 sockfd_put(tx_sock); 1552 if (rx_sock) 1553 sockfd_put(rx_sock); 1554 return err; 1555 } 1556 1557 static int vhost_net_set_backend_features(struct vhost_net *n, u64 features) 1558 { 1559 int i; 1560 1561 mutex_lock(&n->dev.mutex); 1562 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 1563 mutex_lock(&n->vqs[i].vq.mutex); 1564 n->vqs[i].vq.acked_backend_features = features; 1565 mutex_unlock(&n->vqs[i].vq.mutex); 1566 } 1567 mutex_unlock(&n->dev.mutex); 1568 1569 return 0; 1570 } 1571 1572 static int vhost_net_set_features(struct vhost_net *n, u64 features) 1573 { 1574 size_t vhost_hlen, sock_hlen, hdr_len; 1575 int i; 1576 1577 hdr_len = (features & ((1ULL << VIRTIO_NET_F_MRG_RXBUF) | 1578 (1ULL << VIRTIO_F_VERSION_1))) ? 1579 sizeof(struct virtio_net_hdr_mrg_rxbuf) : 1580 sizeof(struct virtio_net_hdr); 1581 if (features & (1 << VHOST_NET_F_VIRTIO_NET_HDR)) { 1582 /* vhost provides vnet_hdr */ 1583 vhost_hlen = hdr_len; 1584 sock_hlen = 0; 1585 } else { 1586 /* socket provides vnet_hdr */ 1587 vhost_hlen = 0; 1588 sock_hlen = hdr_len; 1589 } 1590 mutex_lock(&n->dev.mutex); 1591 if ((features & (1 << VHOST_F_LOG_ALL)) && 1592 !vhost_log_access_ok(&n->dev)) 1593 goto out_unlock; 1594 1595 if ((features & (1ULL << VIRTIO_F_IOMMU_PLATFORM))) { 1596 if (vhost_init_device_iotlb(&n->dev, true)) 1597 goto out_unlock; 1598 } 1599 1600 for (i = 0; i < VHOST_NET_VQ_MAX; ++i) { 1601 mutex_lock(&n->vqs[i].vq.mutex); 1602 n->vqs[i].vq.acked_features = features; 1603 n->vqs[i].vhost_hlen = vhost_hlen; 1604 n->vqs[i].sock_hlen = sock_hlen; 1605 mutex_unlock(&n->vqs[i].vq.mutex); 1606 } 1607 mutex_unlock(&n->dev.mutex); 1608 return 0; 1609 1610 out_unlock: 1611 mutex_unlock(&n->dev.mutex); 1612 return -EFAULT; 1613 } 1614 1615 static long vhost_net_set_owner(struct vhost_net *n) 1616 { 1617 int r; 1618 1619 mutex_lock(&n->dev.mutex); 1620 if (vhost_dev_has_owner(&n->dev)) { 1621 r = -EBUSY; 1622 goto out; 1623 } 1624 r = vhost_net_set_ubuf_info(n); 1625 if (r) 1626 goto out; 1627 r = vhost_dev_set_owner(&n->dev); 1628 if (r) 1629 vhost_net_clear_ubuf_info(n); 1630 vhost_net_flush(n); 1631 out: 1632 mutex_unlock(&n->dev.mutex); 1633 return r; 1634 } 1635 1636 static long vhost_net_ioctl(struct file *f, unsigned int ioctl, 1637 unsigned long arg) 1638 { 1639 struct vhost_net *n = f->private_data; 1640 void __user *argp = (void __user *)arg; 1641 u64 __user *featurep = argp; 1642 struct vhost_vring_file backend; 1643 u64 features; 1644 int r; 1645 1646 switch (ioctl) { 1647 case VHOST_NET_SET_BACKEND: 1648 if (copy_from_user(&backend, argp, sizeof backend)) 1649 return -EFAULT; 1650 return vhost_net_set_backend(n, backend.index, backend.fd); 1651 case VHOST_GET_FEATURES: 1652 features = VHOST_NET_FEATURES; 1653 if (copy_to_user(featurep, &features, sizeof features)) 1654 return -EFAULT; 1655 return 0; 1656 case VHOST_SET_FEATURES: 1657 if (copy_from_user(&features, featurep, sizeof features)) 1658 return -EFAULT; 1659 if (features & ~VHOST_NET_FEATURES) 1660 return -EOPNOTSUPP; 1661 return vhost_net_set_features(n, features); 1662 case VHOST_GET_BACKEND_FEATURES: 1663 features = VHOST_NET_BACKEND_FEATURES; 1664 if (copy_to_user(featurep, &features, sizeof(features))) 1665 return -EFAULT; 1666 return 0; 1667 case VHOST_SET_BACKEND_FEATURES: 1668 if (copy_from_user(&features, featurep, sizeof(features))) 1669 return -EFAULT; 1670 if (features & ~VHOST_NET_BACKEND_FEATURES) 1671 return -EOPNOTSUPP; 1672 return vhost_net_set_backend_features(n, features); 1673 case VHOST_RESET_OWNER: 1674 return vhost_net_reset_owner(n); 1675 case VHOST_SET_OWNER: 1676 return vhost_net_set_owner(n); 1677 default: 1678 mutex_lock(&n->dev.mutex); 1679 r = vhost_dev_ioctl(&n->dev, ioctl, argp); 1680 if (r == -ENOIOCTLCMD) 1681 r = vhost_vring_ioctl(&n->dev, ioctl, argp); 1682 else 1683 vhost_net_flush(n); 1684 mutex_unlock(&n->dev.mutex); 1685 return r; 1686 } 1687 } 1688 1689 #ifdef CONFIG_COMPAT 1690 static long vhost_net_compat_ioctl(struct file *f, unsigned int ioctl, 1691 unsigned long arg) 1692 { 1693 return vhost_net_ioctl(f, ioctl, (unsigned long)compat_ptr(arg)); 1694 } 1695 #endif 1696 1697 static ssize_t vhost_net_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 1698 { 1699 struct file *file = iocb->ki_filp; 1700 struct vhost_net *n = file->private_data; 1701 struct vhost_dev *dev = &n->dev; 1702 int noblock = file->f_flags & O_NONBLOCK; 1703 1704 return vhost_chr_read_iter(dev, to, noblock); 1705 } 1706 1707 static ssize_t vhost_net_chr_write_iter(struct kiocb *iocb, 1708 struct iov_iter *from) 1709 { 1710 struct file *file = iocb->ki_filp; 1711 struct vhost_net *n = file->private_data; 1712 struct vhost_dev *dev = &n->dev; 1713 1714 return vhost_chr_write_iter(dev, from); 1715 } 1716 1717 static __poll_t vhost_net_chr_poll(struct file *file, poll_table *wait) 1718 { 1719 struct vhost_net *n = file->private_data; 1720 struct vhost_dev *dev = &n->dev; 1721 1722 return vhost_chr_poll(file, dev, wait); 1723 } 1724 1725 static const struct file_operations vhost_net_fops = { 1726 .owner = THIS_MODULE, 1727 .release = vhost_net_release, 1728 .read_iter = vhost_net_chr_read_iter, 1729 .write_iter = vhost_net_chr_write_iter, 1730 .poll = vhost_net_chr_poll, 1731 .unlocked_ioctl = vhost_net_ioctl, 1732 #ifdef CONFIG_COMPAT 1733 .compat_ioctl = vhost_net_compat_ioctl, 1734 #endif 1735 .open = vhost_net_open, 1736 .llseek = noop_llseek, 1737 }; 1738 1739 static struct miscdevice vhost_net_misc = { 1740 .minor = VHOST_NET_MINOR, 1741 .name = "vhost-net", 1742 .fops = &vhost_net_fops, 1743 }; 1744 1745 static int vhost_net_init(void) 1746 { 1747 if (experimental_zcopytx) 1748 vhost_net_enable_zcopy(VHOST_NET_VQ_TX); 1749 return misc_register(&vhost_net_misc); 1750 } 1751 module_init(vhost_net_init); 1752 1753 static void vhost_net_exit(void) 1754 { 1755 misc_deregister(&vhost_net_misc); 1756 } 1757 module_exit(vhost_net_exit); 1758 1759 MODULE_VERSION("0.0.1"); 1760 MODULE_LICENSE("GPL v2"); 1761 MODULE_AUTHOR("Michael S. Tsirkin"); 1762 MODULE_DESCRIPTION("Host kernel accelerator for virtio net"); 1763 MODULE_ALIAS_MISCDEV(VHOST_NET_MINOR); 1764 MODULE_ALIAS("devname:vhost-net"); 1765