1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * vhost transport for vsock 4 * 5 * Copyright (C) 2013-2015 Red Hat, Inc. 6 * Author: Asias He <asias@redhat.com> 7 * Stefan Hajnoczi <stefanha@redhat.com> 8 */ 9 #include <linux/miscdevice.h> 10 #include <linux/atomic.h> 11 #include <linux/module.h> 12 #include <linux/mutex.h> 13 #include <linux/vmalloc.h> 14 #include <net/sock.h> 15 #include <linux/virtio_vsock.h> 16 #include <linux/vhost.h> 17 #include <linux/hashtable.h> 18 19 #include <net/af_vsock.h> 20 #include "vhost.h" 21 22 #define VHOST_VSOCK_DEFAULT_HOST_CID 2 23 /* Max number of bytes transferred before requeueing the job. 24 * Using this limit prevents one virtqueue from starving others. */ 25 #define VHOST_VSOCK_WEIGHT 0x80000 26 /* Max number of packets transferred before requeueing the job. 27 * Using this limit prevents one virtqueue from starving others with 28 * small pkts. 29 */ 30 #define VHOST_VSOCK_PKT_WEIGHT 256 31 32 enum { 33 VHOST_VSOCK_FEATURES = VHOST_FEATURES | 34 (1ULL << VIRTIO_F_ACCESS_PLATFORM) | 35 (1ULL << VIRTIO_VSOCK_F_SEQPACKET) 36 }; 37 38 enum { 39 VHOST_VSOCK_BACKEND_FEATURES = (1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2) 40 }; 41 42 /* Used to track all the vhost_vsock instances on the system. */ 43 static DEFINE_MUTEX(vhost_vsock_mutex); 44 static DEFINE_READ_MOSTLY_HASHTABLE(vhost_vsock_hash, 8); 45 46 struct vhost_vsock { 47 struct vhost_dev dev; 48 struct vhost_virtqueue vqs[2]; 49 50 /* Link to global vhost_vsock_hash, writes use vhost_vsock_mutex */ 51 struct hlist_node hash; 52 53 struct vhost_work send_pkt_work; 54 spinlock_t send_pkt_list_lock; 55 struct list_head send_pkt_list; /* host->guest pending packets */ 56 57 atomic_t queued_replies; 58 59 u32 guest_cid; 60 bool seqpacket_allow; 61 }; 62 63 static u32 vhost_transport_get_local_cid(void) 64 { 65 return VHOST_VSOCK_DEFAULT_HOST_CID; 66 } 67 68 /* Callers that dereference the return value must hold vhost_vsock_mutex or the 69 * RCU read lock. 70 */ 71 static struct vhost_vsock *vhost_vsock_get(u32 guest_cid) 72 { 73 struct vhost_vsock *vsock; 74 75 hash_for_each_possible_rcu(vhost_vsock_hash, vsock, hash, guest_cid) { 76 u32 other_cid = vsock->guest_cid; 77 78 /* Skip instances that have no CID yet */ 79 if (other_cid == 0) 80 continue; 81 82 if (other_cid == guest_cid) 83 return vsock; 84 85 } 86 87 return NULL; 88 } 89 90 static void 91 vhost_transport_do_send_pkt(struct vhost_vsock *vsock, 92 struct vhost_virtqueue *vq) 93 { 94 struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX]; 95 int pkts = 0, total_len = 0; 96 bool added = false; 97 bool restart_tx = false; 98 99 mutex_lock(&vq->mutex); 100 101 if (!vhost_vq_get_backend(vq)) 102 goto out; 103 104 if (!vq_meta_prefetch(vq)) 105 goto out; 106 107 /* Avoid further vmexits, we're already processing the virtqueue */ 108 vhost_disable_notify(&vsock->dev, vq); 109 110 do { 111 struct virtio_vsock_pkt *pkt; 112 struct iov_iter iov_iter; 113 unsigned out, in; 114 size_t nbytes; 115 size_t iov_len, payload_len; 116 int head; 117 u32 flags_to_restore = 0; 118 119 spin_lock_bh(&vsock->send_pkt_list_lock); 120 if (list_empty(&vsock->send_pkt_list)) { 121 spin_unlock_bh(&vsock->send_pkt_list_lock); 122 vhost_enable_notify(&vsock->dev, vq); 123 break; 124 } 125 126 pkt = list_first_entry(&vsock->send_pkt_list, 127 struct virtio_vsock_pkt, list); 128 list_del_init(&pkt->list); 129 spin_unlock_bh(&vsock->send_pkt_list_lock); 130 131 head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov), 132 &out, &in, NULL, NULL); 133 if (head < 0) { 134 spin_lock_bh(&vsock->send_pkt_list_lock); 135 list_add(&pkt->list, &vsock->send_pkt_list); 136 spin_unlock_bh(&vsock->send_pkt_list_lock); 137 break; 138 } 139 140 if (head == vq->num) { 141 spin_lock_bh(&vsock->send_pkt_list_lock); 142 list_add(&pkt->list, &vsock->send_pkt_list); 143 spin_unlock_bh(&vsock->send_pkt_list_lock); 144 145 /* We cannot finish yet if more buffers snuck in while 146 * re-enabling notify. 147 */ 148 if (unlikely(vhost_enable_notify(&vsock->dev, vq))) { 149 vhost_disable_notify(&vsock->dev, vq); 150 continue; 151 } 152 break; 153 } 154 155 if (out) { 156 virtio_transport_free_pkt(pkt); 157 vq_err(vq, "Expected 0 output buffers, got %u\n", out); 158 break; 159 } 160 161 iov_len = iov_length(&vq->iov[out], in); 162 if (iov_len < sizeof(pkt->hdr)) { 163 virtio_transport_free_pkt(pkt); 164 vq_err(vq, "Buffer len [%zu] too small\n", iov_len); 165 break; 166 } 167 168 iov_iter_init(&iov_iter, READ, &vq->iov[out], in, iov_len); 169 payload_len = pkt->len - pkt->off; 170 171 /* If the packet is greater than the space available in the 172 * buffer, we split it using multiple buffers. 173 */ 174 if (payload_len > iov_len - sizeof(pkt->hdr)) { 175 payload_len = iov_len - sizeof(pkt->hdr); 176 177 /* As we are copying pieces of large packet's buffer to 178 * small rx buffers, headers of packets in rx queue are 179 * created dynamically and are initialized with header 180 * of current packet(except length). But in case of 181 * SOCK_SEQPACKET, we also must clear message delimeter 182 * bit (VIRTIO_VSOCK_SEQ_EOM) and MSG_EOR bit 183 * (VIRTIO_VSOCK_SEQ_EOR) if set. Otherwise, 184 * there will be sequence of packets with these 185 * bits set. After initialized header will be copied to 186 * rx buffer, these required bits will be restored. 187 */ 188 if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOM) { 189 pkt->hdr.flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM); 190 flags_to_restore |= VIRTIO_VSOCK_SEQ_EOM; 191 192 if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOR) { 193 pkt->hdr.flags &= ~cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR); 194 flags_to_restore |= VIRTIO_VSOCK_SEQ_EOR; 195 } 196 } 197 } 198 199 /* Set the correct length in the header */ 200 pkt->hdr.len = cpu_to_le32(payload_len); 201 202 nbytes = copy_to_iter(&pkt->hdr, sizeof(pkt->hdr), &iov_iter); 203 if (nbytes != sizeof(pkt->hdr)) { 204 virtio_transport_free_pkt(pkt); 205 vq_err(vq, "Faulted on copying pkt hdr\n"); 206 break; 207 } 208 209 nbytes = copy_to_iter(pkt->buf + pkt->off, payload_len, 210 &iov_iter); 211 if (nbytes != payload_len) { 212 virtio_transport_free_pkt(pkt); 213 vq_err(vq, "Faulted on copying pkt buf\n"); 214 break; 215 } 216 217 /* Deliver to monitoring devices all packets that we 218 * will transmit. 219 */ 220 virtio_transport_deliver_tap_pkt(pkt); 221 222 vhost_add_used(vq, head, sizeof(pkt->hdr) + payload_len); 223 added = true; 224 225 pkt->off += payload_len; 226 total_len += payload_len; 227 228 /* If we didn't send all the payload we can requeue the packet 229 * to send it with the next available buffer. 230 */ 231 if (pkt->off < pkt->len) { 232 pkt->hdr.flags |= cpu_to_le32(flags_to_restore); 233 234 /* We are queueing the same virtio_vsock_pkt to handle 235 * the remaining bytes, and we want to deliver it 236 * to monitoring devices in the next iteration. 237 */ 238 pkt->tap_delivered = false; 239 240 spin_lock_bh(&vsock->send_pkt_list_lock); 241 list_add(&pkt->list, &vsock->send_pkt_list); 242 spin_unlock_bh(&vsock->send_pkt_list_lock); 243 } else { 244 if (pkt->reply) { 245 int val; 246 247 val = atomic_dec_return(&vsock->queued_replies); 248 249 /* Do we have resources to resume tx 250 * processing? 251 */ 252 if (val + 1 == tx_vq->num) 253 restart_tx = true; 254 } 255 256 virtio_transport_free_pkt(pkt); 257 } 258 } while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len))); 259 if (added) 260 vhost_signal(&vsock->dev, vq); 261 262 out: 263 mutex_unlock(&vq->mutex); 264 265 if (restart_tx) 266 vhost_poll_queue(&tx_vq->poll); 267 } 268 269 static void vhost_transport_send_pkt_work(struct vhost_work *work) 270 { 271 struct vhost_virtqueue *vq; 272 struct vhost_vsock *vsock; 273 274 vsock = container_of(work, struct vhost_vsock, send_pkt_work); 275 vq = &vsock->vqs[VSOCK_VQ_RX]; 276 277 vhost_transport_do_send_pkt(vsock, vq); 278 } 279 280 static int 281 vhost_transport_send_pkt(struct virtio_vsock_pkt *pkt) 282 { 283 struct vhost_vsock *vsock; 284 int len = pkt->len; 285 286 rcu_read_lock(); 287 288 /* Find the vhost_vsock according to guest context id */ 289 vsock = vhost_vsock_get(le64_to_cpu(pkt->hdr.dst_cid)); 290 if (!vsock) { 291 rcu_read_unlock(); 292 virtio_transport_free_pkt(pkt); 293 return -ENODEV; 294 } 295 296 if (pkt->reply) 297 atomic_inc(&vsock->queued_replies); 298 299 spin_lock_bh(&vsock->send_pkt_list_lock); 300 list_add_tail(&pkt->list, &vsock->send_pkt_list); 301 spin_unlock_bh(&vsock->send_pkt_list_lock); 302 303 vhost_work_queue(&vsock->dev, &vsock->send_pkt_work); 304 305 rcu_read_unlock(); 306 return len; 307 } 308 309 static int 310 vhost_transport_cancel_pkt(struct vsock_sock *vsk) 311 { 312 struct vhost_vsock *vsock; 313 struct virtio_vsock_pkt *pkt, *n; 314 int cnt = 0; 315 int ret = -ENODEV; 316 LIST_HEAD(freeme); 317 318 rcu_read_lock(); 319 320 /* Find the vhost_vsock according to guest context id */ 321 vsock = vhost_vsock_get(vsk->remote_addr.svm_cid); 322 if (!vsock) 323 goto out; 324 325 spin_lock_bh(&vsock->send_pkt_list_lock); 326 list_for_each_entry_safe(pkt, n, &vsock->send_pkt_list, list) { 327 if (pkt->vsk != vsk) 328 continue; 329 list_move(&pkt->list, &freeme); 330 } 331 spin_unlock_bh(&vsock->send_pkt_list_lock); 332 333 list_for_each_entry_safe(pkt, n, &freeme, list) { 334 if (pkt->reply) 335 cnt++; 336 list_del(&pkt->list); 337 virtio_transport_free_pkt(pkt); 338 } 339 340 if (cnt) { 341 struct vhost_virtqueue *tx_vq = &vsock->vqs[VSOCK_VQ_TX]; 342 int new_cnt; 343 344 new_cnt = atomic_sub_return(cnt, &vsock->queued_replies); 345 if (new_cnt + cnt >= tx_vq->num && new_cnt < tx_vq->num) 346 vhost_poll_queue(&tx_vq->poll); 347 } 348 349 ret = 0; 350 out: 351 rcu_read_unlock(); 352 return ret; 353 } 354 355 static struct virtio_vsock_pkt * 356 vhost_vsock_alloc_pkt(struct vhost_virtqueue *vq, 357 unsigned int out, unsigned int in) 358 { 359 struct virtio_vsock_pkt *pkt; 360 struct iov_iter iov_iter; 361 size_t nbytes; 362 size_t len; 363 364 if (in != 0) { 365 vq_err(vq, "Expected 0 input buffers, got %u\n", in); 366 return NULL; 367 } 368 369 pkt = kzalloc(sizeof(*pkt), GFP_KERNEL); 370 if (!pkt) 371 return NULL; 372 373 len = iov_length(vq->iov, out); 374 iov_iter_init(&iov_iter, WRITE, vq->iov, out, len); 375 376 nbytes = copy_from_iter(&pkt->hdr, sizeof(pkt->hdr), &iov_iter); 377 if (nbytes != sizeof(pkt->hdr)) { 378 vq_err(vq, "Expected %zu bytes for pkt->hdr, got %zu bytes\n", 379 sizeof(pkt->hdr), nbytes); 380 kfree(pkt); 381 return NULL; 382 } 383 384 pkt->len = le32_to_cpu(pkt->hdr.len); 385 386 /* No payload */ 387 if (!pkt->len) 388 return pkt; 389 390 /* The pkt is too big */ 391 if (pkt->len > VIRTIO_VSOCK_MAX_PKT_BUF_SIZE) { 392 kfree(pkt); 393 return NULL; 394 } 395 396 pkt->buf = kmalloc(pkt->len, GFP_KERNEL); 397 if (!pkt->buf) { 398 kfree(pkt); 399 return NULL; 400 } 401 402 pkt->buf_len = pkt->len; 403 404 nbytes = copy_from_iter(pkt->buf, pkt->len, &iov_iter); 405 if (nbytes != pkt->len) { 406 vq_err(vq, "Expected %u byte payload, got %zu bytes\n", 407 pkt->len, nbytes); 408 virtio_transport_free_pkt(pkt); 409 return NULL; 410 } 411 412 return pkt; 413 } 414 415 /* Is there space left for replies to rx packets? */ 416 static bool vhost_vsock_more_replies(struct vhost_vsock *vsock) 417 { 418 struct vhost_virtqueue *vq = &vsock->vqs[VSOCK_VQ_TX]; 419 int val; 420 421 smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */ 422 val = atomic_read(&vsock->queued_replies); 423 424 return val < vq->num; 425 } 426 427 static bool vhost_transport_seqpacket_allow(u32 remote_cid); 428 429 static struct virtio_transport vhost_transport = { 430 .transport = { 431 .module = THIS_MODULE, 432 433 .get_local_cid = vhost_transport_get_local_cid, 434 435 .init = virtio_transport_do_socket_init, 436 .destruct = virtio_transport_destruct, 437 .release = virtio_transport_release, 438 .connect = virtio_transport_connect, 439 .shutdown = virtio_transport_shutdown, 440 .cancel_pkt = vhost_transport_cancel_pkt, 441 442 .dgram_enqueue = virtio_transport_dgram_enqueue, 443 .dgram_dequeue = virtio_transport_dgram_dequeue, 444 .dgram_bind = virtio_transport_dgram_bind, 445 .dgram_allow = virtio_transport_dgram_allow, 446 447 .stream_enqueue = virtio_transport_stream_enqueue, 448 .stream_dequeue = virtio_transport_stream_dequeue, 449 .stream_has_data = virtio_transport_stream_has_data, 450 .stream_has_space = virtio_transport_stream_has_space, 451 .stream_rcvhiwat = virtio_transport_stream_rcvhiwat, 452 .stream_is_active = virtio_transport_stream_is_active, 453 .stream_allow = virtio_transport_stream_allow, 454 455 .seqpacket_dequeue = virtio_transport_seqpacket_dequeue, 456 .seqpacket_enqueue = virtio_transport_seqpacket_enqueue, 457 .seqpacket_allow = vhost_transport_seqpacket_allow, 458 .seqpacket_has_data = virtio_transport_seqpacket_has_data, 459 460 .notify_poll_in = virtio_transport_notify_poll_in, 461 .notify_poll_out = virtio_transport_notify_poll_out, 462 .notify_recv_init = virtio_transport_notify_recv_init, 463 .notify_recv_pre_block = virtio_transport_notify_recv_pre_block, 464 .notify_recv_pre_dequeue = virtio_transport_notify_recv_pre_dequeue, 465 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue, 466 .notify_send_init = virtio_transport_notify_send_init, 467 .notify_send_pre_block = virtio_transport_notify_send_pre_block, 468 .notify_send_pre_enqueue = virtio_transport_notify_send_pre_enqueue, 469 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue, 470 .notify_buffer_size = virtio_transport_notify_buffer_size, 471 472 }, 473 474 .send_pkt = vhost_transport_send_pkt, 475 }; 476 477 static bool vhost_transport_seqpacket_allow(u32 remote_cid) 478 { 479 struct vhost_vsock *vsock; 480 bool seqpacket_allow = false; 481 482 rcu_read_lock(); 483 vsock = vhost_vsock_get(remote_cid); 484 485 if (vsock) 486 seqpacket_allow = vsock->seqpacket_allow; 487 488 rcu_read_unlock(); 489 490 return seqpacket_allow; 491 } 492 493 static void vhost_vsock_handle_tx_kick(struct vhost_work *work) 494 { 495 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 496 poll.work); 497 struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock, 498 dev); 499 struct virtio_vsock_pkt *pkt; 500 int head, pkts = 0, total_len = 0; 501 unsigned int out, in; 502 bool added = false; 503 504 mutex_lock(&vq->mutex); 505 506 if (!vhost_vq_get_backend(vq)) 507 goto out; 508 509 if (!vq_meta_prefetch(vq)) 510 goto out; 511 512 vhost_disable_notify(&vsock->dev, vq); 513 do { 514 u32 len; 515 516 if (!vhost_vsock_more_replies(vsock)) { 517 /* Stop tx until the device processes already 518 * pending replies. Leave tx virtqueue 519 * callbacks disabled. 520 */ 521 goto no_more_replies; 522 } 523 524 head = vhost_get_vq_desc(vq, vq->iov, ARRAY_SIZE(vq->iov), 525 &out, &in, NULL, NULL); 526 if (head < 0) 527 break; 528 529 if (head == vq->num) { 530 if (unlikely(vhost_enable_notify(&vsock->dev, vq))) { 531 vhost_disable_notify(&vsock->dev, vq); 532 continue; 533 } 534 break; 535 } 536 537 pkt = vhost_vsock_alloc_pkt(vq, out, in); 538 if (!pkt) { 539 vq_err(vq, "Faulted on pkt\n"); 540 continue; 541 } 542 543 len = pkt->len; 544 545 /* Deliver to monitoring devices all received packets */ 546 virtio_transport_deliver_tap_pkt(pkt); 547 548 /* Only accept correctly addressed packets */ 549 if (le64_to_cpu(pkt->hdr.src_cid) == vsock->guest_cid && 550 le64_to_cpu(pkt->hdr.dst_cid) == 551 vhost_transport_get_local_cid()) 552 virtio_transport_recv_pkt(&vhost_transport, pkt); 553 else 554 virtio_transport_free_pkt(pkt); 555 556 len += sizeof(pkt->hdr); 557 vhost_add_used(vq, head, len); 558 total_len += len; 559 added = true; 560 } while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len))); 561 562 no_more_replies: 563 if (added) 564 vhost_signal(&vsock->dev, vq); 565 566 out: 567 mutex_unlock(&vq->mutex); 568 } 569 570 static void vhost_vsock_handle_rx_kick(struct vhost_work *work) 571 { 572 struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue, 573 poll.work); 574 struct vhost_vsock *vsock = container_of(vq->dev, struct vhost_vsock, 575 dev); 576 577 vhost_transport_do_send_pkt(vsock, vq); 578 } 579 580 static int vhost_vsock_start(struct vhost_vsock *vsock) 581 { 582 struct vhost_virtqueue *vq; 583 size_t i; 584 int ret; 585 586 mutex_lock(&vsock->dev.mutex); 587 588 ret = vhost_dev_check_owner(&vsock->dev); 589 if (ret) 590 goto err; 591 592 for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) { 593 vq = &vsock->vqs[i]; 594 595 mutex_lock(&vq->mutex); 596 597 if (!vhost_vq_access_ok(vq)) { 598 ret = -EFAULT; 599 goto err_vq; 600 } 601 602 if (!vhost_vq_get_backend(vq)) { 603 vhost_vq_set_backend(vq, vsock); 604 ret = vhost_vq_init_access(vq); 605 if (ret) 606 goto err_vq; 607 } 608 609 mutex_unlock(&vq->mutex); 610 } 611 612 /* Some packets may have been queued before the device was started, 613 * let's kick the send worker to send them. 614 */ 615 vhost_work_queue(&vsock->dev, &vsock->send_pkt_work); 616 617 mutex_unlock(&vsock->dev.mutex); 618 return 0; 619 620 err_vq: 621 vhost_vq_set_backend(vq, NULL); 622 mutex_unlock(&vq->mutex); 623 624 for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) { 625 vq = &vsock->vqs[i]; 626 627 mutex_lock(&vq->mutex); 628 vhost_vq_set_backend(vq, NULL); 629 mutex_unlock(&vq->mutex); 630 } 631 err: 632 mutex_unlock(&vsock->dev.mutex); 633 return ret; 634 } 635 636 static int vhost_vsock_stop(struct vhost_vsock *vsock) 637 { 638 size_t i; 639 int ret; 640 641 mutex_lock(&vsock->dev.mutex); 642 643 ret = vhost_dev_check_owner(&vsock->dev); 644 if (ret) 645 goto err; 646 647 for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) { 648 struct vhost_virtqueue *vq = &vsock->vqs[i]; 649 650 mutex_lock(&vq->mutex); 651 vhost_vq_set_backend(vq, NULL); 652 mutex_unlock(&vq->mutex); 653 } 654 655 err: 656 mutex_unlock(&vsock->dev.mutex); 657 return ret; 658 } 659 660 static void vhost_vsock_free(struct vhost_vsock *vsock) 661 { 662 kvfree(vsock); 663 } 664 665 static int vhost_vsock_dev_open(struct inode *inode, struct file *file) 666 { 667 struct vhost_virtqueue **vqs; 668 struct vhost_vsock *vsock; 669 int ret; 670 671 /* This struct is large and allocation could fail, fall back to vmalloc 672 * if there is no other way. 673 */ 674 vsock = kvmalloc(sizeof(*vsock), GFP_KERNEL | __GFP_RETRY_MAYFAIL); 675 if (!vsock) 676 return -ENOMEM; 677 678 vqs = kmalloc_array(ARRAY_SIZE(vsock->vqs), sizeof(*vqs), GFP_KERNEL); 679 if (!vqs) { 680 ret = -ENOMEM; 681 goto out; 682 } 683 684 vsock->guest_cid = 0; /* no CID assigned yet */ 685 686 atomic_set(&vsock->queued_replies, 0); 687 688 vqs[VSOCK_VQ_TX] = &vsock->vqs[VSOCK_VQ_TX]; 689 vqs[VSOCK_VQ_RX] = &vsock->vqs[VSOCK_VQ_RX]; 690 vsock->vqs[VSOCK_VQ_TX].handle_kick = vhost_vsock_handle_tx_kick; 691 vsock->vqs[VSOCK_VQ_RX].handle_kick = vhost_vsock_handle_rx_kick; 692 693 vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs), 694 UIO_MAXIOV, VHOST_VSOCK_PKT_WEIGHT, 695 VHOST_VSOCK_WEIGHT, true, NULL); 696 697 file->private_data = vsock; 698 spin_lock_init(&vsock->send_pkt_list_lock); 699 INIT_LIST_HEAD(&vsock->send_pkt_list); 700 vhost_work_init(&vsock->send_pkt_work, vhost_transport_send_pkt_work); 701 return 0; 702 703 out: 704 vhost_vsock_free(vsock); 705 return ret; 706 } 707 708 static void vhost_vsock_flush(struct vhost_vsock *vsock) 709 { 710 int i; 711 712 for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) 713 if (vsock->vqs[i].handle_kick) 714 vhost_poll_flush(&vsock->vqs[i].poll); 715 vhost_work_dev_flush(&vsock->dev); 716 } 717 718 static void vhost_vsock_reset_orphans(struct sock *sk) 719 { 720 struct vsock_sock *vsk = vsock_sk(sk); 721 722 /* vmci_transport.c doesn't take sk_lock here either. At least we're 723 * under vsock_table_lock so the sock cannot disappear while we're 724 * executing. 725 */ 726 727 /* If the peer is still valid, no need to reset connection */ 728 if (vhost_vsock_get(vsk->remote_addr.svm_cid)) 729 return; 730 731 /* If the close timeout is pending, let it expire. This avoids races 732 * with the timeout callback. 733 */ 734 if (vsk->close_work_scheduled) 735 return; 736 737 sock_set_flag(sk, SOCK_DONE); 738 vsk->peer_shutdown = SHUTDOWN_MASK; 739 sk->sk_state = SS_UNCONNECTED; 740 sk->sk_err = ECONNRESET; 741 sk_error_report(sk); 742 } 743 744 static int vhost_vsock_dev_release(struct inode *inode, struct file *file) 745 { 746 struct vhost_vsock *vsock = file->private_data; 747 748 mutex_lock(&vhost_vsock_mutex); 749 if (vsock->guest_cid) 750 hash_del_rcu(&vsock->hash); 751 mutex_unlock(&vhost_vsock_mutex); 752 753 /* Wait for other CPUs to finish using vsock */ 754 synchronize_rcu(); 755 756 /* Iterating over all connections for all CIDs to find orphans is 757 * inefficient. Room for improvement here. */ 758 vsock_for_each_connected_socket(vhost_vsock_reset_orphans); 759 760 vhost_vsock_stop(vsock); 761 vhost_vsock_flush(vsock); 762 vhost_dev_stop(&vsock->dev); 763 764 spin_lock_bh(&vsock->send_pkt_list_lock); 765 while (!list_empty(&vsock->send_pkt_list)) { 766 struct virtio_vsock_pkt *pkt; 767 768 pkt = list_first_entry(&vsock->send_pkt_list, 769 struct virtio_vsock_pkt, list); 770 list_del_init(&pkt->list); 771 virtio_transport_free_pkt(pkt); 772 } 773 spin_unlock_bh(&vsock->send_pkt_list_lock); 774 775 vhost_dev_cleanup(&vsock->dev); 776 kfree(vsock->dev.vqs); 777 vhost_vsock_free(vsock); 778 return 0; 779 } 780 781 static int vhost_vsock_set_cid(struct vhost_vsock *vsock, u64 guest_cid) 782 { 783 struct vhost_vsock *other; 784 785 /* Refuse reserved CIDs */ 786 if (guest_cid <= VMADDR_CID_HOST || 787 guest_cid == U32_MAX) 788 return -EINVAL; 789 790 /* 64-bit CIDs are not yet supported */ 791 if (guest_cid > U32_MAX) 792 return -EINVAL; 793 794 /* Refuse if CID is assigned to the guest->host transport (i.e. nested 795 * VM), to make the loopback work. 796 */ 797 if (vsock_find_cid(guest_cid)) 798 return -EADDRINUSE; 799 800 /* Refuse if CID is already in use */ 801 mutex_lock(&vhost_vsock_mutex); 802 other = vhost_vsock_get(guest_cid); 803 if (other && other != vsock) { 804 mutex_unlock(&vhost_vsock_mutex); 805 return -EADDRINUSE; 806 } 807 808 if (vsock->guest_cid) 809 hash_del_rcu(&vsock->hash); 810 811 vsock->guest_cid = guest_cid; 812 hash_add_rcu(vhost_vsock_hash, &vsock->hash, vsock->guest_cid); 813 mutex_unlock(&vhost_vsock_mutex); 814 815 return 0; 816 } 817 818 static int vhost_vsock_set_features(struct vhost_vsock *vsock, u64 features) 819 { 820 struct vhost_virtqueue *vq; 821 int i; 822 823 if (features & ~VHOST_VSOCK_FEATURES) 824 return -EOPNOTSUPP; 825 826 mutex_lock(&vsock->dev.mutex); 827 if ((features & (1 << VHOST_F_LOG_ALL)) && 828 !vhost_log_access_ok(&vsock->dev)) { 829 goto err; 830 } 831 832 if ((features & (1ULL << VIRTIO_F_ACCESS_PLATFORM))) { 833 if (vhost_init_device_iotlb(&vsock->dev, true)) 834 goto err; 835 } 836 837 if (features & (1ULL << VIRTIO_VSOCK_F_SEQPACKET)) 838 vsock->seqpacket_allow = true; 839 840 for (i = 0; i < ARRAY_SIZE(vsock->vqs); i++) { 841 vq = &vsock->vqs[i]; 842 mutex_lock(&vq->mutex); 843 vq->acked_features = features; 844 mutex_unlock(&vq->mutex); 845 } 846 mutex_unlock(&vsock->dev.mutex); 847 return 0; 848 849 err: 850 mutex_unlock(&vsock->dev.mutex); 851 return -EFAULT; 852 } 853 854 static long vhost_vsock_dev_ioctl(struct file *f, unsigned int ioctl, 855 unsigned long arg) 856 { 857 struct vhost_vsock *vsock = f->private_data; 858 void __user *argp = (void __user *)arg; 859 u64 guest_cid; 860 u64 features; 861 int start; 862 int r; 863 864 switch (ioctl) { 865 case VHOST_VSOCK_SET_GUEST_CID: 866 if (copy_from_user(&guest_cid, argp, sizeof(guest_cid))) 867 return -EFAULT; 868 return vhost_vsock_set_cid(vsock, guest_cid); 869 case VHOST_VSOCK_SET_RUNNING: 870 if (copy_from_user(&start, argp, sizeof(start))) 871 return -EFAULT; 872 if (start) 873 return vhost_vsock_start(vsock); 874 else 875 return vhost_vsock_stop(vsock); 876 case VHOST_GET_FEATURES: 877 features = VHOST_VSOCK_FEATURES; 878 if (copy_to_user(argp, &features, sizeof(features))) 879 return -EFAULT; 880 return 0; 881 case VHOST_SET_FEATURES: 882 if (copy_from_user(&features, argp, sizeof(features))) 883 return -EFAULT; 884 return vhost_vsock_set_features(vsock, features); 885 case VHOST_GET_BACKEND_FEATURES: 886 features = VHOST_VSOCK_BACKEND_FEATURES; 887 if (copy_to_user(argp, &features, sizeof(features))) 888 return -EFAULT; 889 return 0; 890 case VHOST_SET_BACKEND_FEATURES: 891 if (copy_from_user(&features, argp, sizeof(features))) 892 return -EFAULT; 893 if (features & ~VHOST_VSOCK_BACKEND_FEATURES) 894 return -EOPNOTSUPP; 895 vhost_set_backend_features(&vsock->dev, features); 896 return 0; 897 default: 898 mutex_lock(&vsock->dev.mutex); 899 r = vhost_dev_ioctl(&vsock->dev, ioctl, argp); 900 if (r == -ENOIOCTLCMD) 901 r = vhost_vring_ioctl(&vsock->dev, ioctl, argp); 902 else 903 vhost_vsock_flush(vsock); 904 mutex_unlock(&vsock->dev.mutex); 905 return r; 906 } 907 } 908 909 static ssize_t vhost_vsock_chr_read_iter(struct kiocb *iocb, struct iov_iter *to) 910 { 911 struct file *file = iocb->ki_filp; 912 struct vhost_vsock *vsock = file->private_data; 913 struct vhost_dev *dev = &vsock->dev; 914 int noblock = file->f_flags & O_NONBLOCK; 915 916 return vhost_chr_read_iter(dev, to, noblock); 917 } 918 919 static ssize_t vhost_vsock_chr_write_iter(struct kiocb *iocb, 920 struct iov_iter *from) 921 { 922 struct file *file = iocb->ki_filp; 923 struct vhost_vsock *vsock = file->private_data; 924 struct vhost_dev *dev = &vsock->dev; 925 926 return vhost_chr_write_iter(dev, from); 927 } 928 929 static __poll_t vhost_vsock_chr_poll(struct file *file, poll_table *wait) 930 { 931 struct vhost_vsock *vsock = file->private_data; 932 struct vhost_dev *dev = &vsock->dev; 933 934 return vhost_chr_poll(file, dev, wait); 935 } 936 937 static const struct file_operations vhost_vsock_fops = { 938 .owner = THIS_MODULE, 939 .open = vhost_vsock_dev_open, 940 .release = vhost_vsock_dev_release, 941 .llseek = noop_llseek, 942 .unlocked_ioctl = vhost_vsock_dev_ioctl, 943 .compat_ioctl = compat_ptr_ioctl, 944 .read_iter = vhost_vsock_chr_read_iter, 945 .write_iter = vhost_vsock_chr_write_iter, 946 .poll = vhost_vsock_chr_poll, 947 }; 948 949 static struct miscdevice vhost_vsock_misc = { 950 .minor = VHOST_VSOCK_MINOR, 951 .name = "vhost-vsock", 952 .fops = &vhost_vsock_fops, 953 }; 954 955 static int __init vhost_vsock_init(void) 956 { 957 int ret; 958 959 ret = vsock_core_register(&vhost_transport.transport, 960 VSOCK_TRANSPORT_F_H2G); 961 if (ret < 0) 962 return ret; 963 return misc_register(&vhost_vsock_misc); 964 }; 965 966 static void __exit vhost_vsock_exit(void) 967 { 968 misc_deregister(&vhost_vsock_misc); 969 vsock_core_unregister(&vhost_transport.transport); 970 }; 971 972 module_init(vhost_vsock_init); 973 module_exit(vhost_vsock_exit); 974 MODULE_LICENSE("GPL v2"); 975 MODULE_AUTHOR("Asias He"); 976 MODULE_DESCRIPTION("vhost transport for vsock "); 977 MODULE_ALIAS_MISCDEV(VHOST_VSOCK_MINOR); 978 MODULE_ALIAS("devname:vhost-vsock"); 979