1 /* 2 * virtio transport for vsock 3 * 4 * Copyright (C) 2013-2015 Red Hat, Inc. 5 * Author: Asias He <asias@redhat.com> 6 * Stefan Hajnoczi <stefanha@redhat.com> 7 * 8 * Some of the code is take from Gerd Hoffmann <kraxel@redhat.com>'s 9 * early virtio-vsock proof-of-concept bits. 10 * 11 * This work is licensed under the terms of the GNU GPL, version 2. 12 */ 13 #include <linux/spinlock.h> 14 #include <linux/module.h> 15 #include <linux/list.h> 16 #include <linux/atomic.h> 17 #include <linux/virtio.h> 18 #include <linux/virtio_ids.h> 19 #include <linux/virtio_config.h> 20 #include <linux/virtio_vsock.h> 21 #include <net/sock.h> 22 #include <linux/mutex.h> 23 #include <net/af_vsock.h> 24 25 static struct workqueue_struct *virtio_vsock_workqueue; 26 static struct virtio_vsock *the_virtio_vsock; 27 static DEFINE_MUTEX(the_virtio_vsock_mutex); /* protects the_virtio_vsock */ 28 29 struct virtio_vsock { 30 struct virtio_device *vdev; 31 struct virtqueue *vqs[VSOCK_VQ_MAX]; 32 33 /* Virtqueue processing is deferred to a workqueue */ 34 struct work_struct tx_work; 35 struct work_struct rx_work; 36 struct work_struct event_work; 37 38 /* The following fields are protected by tx_lock. vqs[VSOCK_VQ_TX] 39 * must be accessed with tx_lock held. 40 */ 41 struct mutex tx_lock; 42 43 struct work_struct send_pkt_work; 44 spinlock_t send_pkt_list_lock; 45 struct list_head send_pkt_list; 46 47 atomic_t queued_replies; 48 49 /* The following fields are protected by rx_lock. vqs[VSOCK_VQ_RX] 50 * must be accessed with rx_lock held. 51 */ 52 struct mutex rx_lock; 53 int rx_buf_nr; 54 int rx_buf_max_nr; 55 56 /* The following fields are protected by event_lock. 57 * vqs[VSOCK_VQ_EVENT] must be accessed with event_lock held. 58 */ 59 struct mutex event_lock; 60 struct virtio_vsock_event event_list[8]; 61 62 u32 guest_cid; 63 }; 64 65 static struct virtio_vsock *virtio_vsock_get(void) 66 { 67 return the_virtio_vsock; 68 } 69 70 static u32 virtio_transport_get_local_cid(void) 71 { 72 struct virtio_vsock *vsock = virtio_vsock_get(); 73 74 return vsock->guest_cid; 75 } 76 77 static void 78 virtio_transport_send_pkt_work(struct work_struct *work) 79 { 80 struct virtio_vsock *vsock = 81 container_of(work, struct virtio_vsock, send_pkt_work); 82 struct virtqueue *vq; 83 bool added = false; 84 bool restart_rx = false; 85 86 mutex_lock(&vsock->tx_lock); 87 88 vq = vsock->vqs[VSOCK_VQ_TX]; 89 90 /* Avoid unnecessary interrupts while we're processing the ring */ 91 virtqueue_disable_cb(vq); 92 93 for (;;) { 94 struct virtio_vsock_pkt *pkt; 95 struct scatterlist hdr, buf, *sgs[2]; 96 int ret, in_sg = 0, out_sg = 0; 97 bool reply; 98 99 spin_lock_bh(&vsock->send_pkt_list_lock); 100 if (list_empty(&vsock->send_pkt_list)) { 101 spin_unlock_bh(&vsock->send_pkt_list_lock); 102 virtqueue_enable_cb(vq); 103 break; 104 } 105 106 pkt = list_first_entry(&vsock->send_pkt_list, 107 struct virtio_vsock_pkt, list); 108 list_del_init(&pkt->list); 109 spin_unlock_bh(&vsock->send_pkt_list_lock); 110 111 reply = pkt->reply; 112 113 sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr)); 114 sgs[out_sg++] = &hdr; 115 if (pkt->buf) { 116 sg_init_one(&buf, pkt->buf, pkt->len); 117 sgs[out_sg++] = &buf; 118 } 119 120 ret = virtqueue_add_sgs(vq, sgs, out_sg, in_sg, pkt, GFP_KERNEL); 121 if (ret < 0) { 122 spin_lock_bh(&vsock->send_pkt_list_lock); 123 list_add(&pkt->list, &vsock->send_pkt_list); 124 spin_unlock_bh(&vsock->send_pkt_list_lock); 125 126 if (!virtqueue_enable_cb(vq) && ret == -ENOSPC) 127 continue; /* retry now that we have more space */ 128 break; 129 } 130 131 if (reply) { 132 struct virtqueue *rx_vq = vsock->vqs[VSOCK_VQ_RX]; 133 int val; 134 135 val = atomic_dec_return(&vsock->queued_replies); 136 137 /* Do we now have resources to resume rx processing? */ 138 if (val + 1 == virtqueue_get_vring_size(rx_vq)) 139 restart_rx = true; 140 } 141 142 added = true; 143 } 144 145 if (added) 146 virtqueue_kick(vq); 147 148 mutex_unlock(&vsock->tx_lock); 149 150 if (restart_rx) 151 queue_work(virtio_vsock_workqueue, &vsock->rx_work); 152 } 153 154 static int 155 virtio_transport_send_pkt(struct virtio_vsock_pkt *pkt) 156 { 157 struct virtio_vsock *vsock; 158 int len = pkt->len; 159 160 vsock = virtio_vsock_get(); 161 if (!vsock) { 162 virtio_transport_free_pkt(pkt); 163 return -ENODEV; 164 } 165 166 if (pkt->reply) 167 atomic_inc(&vsock->queued_replies); 168 169 spin_lock_bh(&vsock->send_pkt_list_lock); 170 list_add_tail(&pkt->list, &vsock->send_pkt_list); 171 spin_unlock_bh(&vsock->send_pkt_list_lock); 172 173 queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work); 174 return len; 175 } 176 177 static void virtio_vsock_rx_fill(struct virtio_vsock *vsock) 178 { 179 int buf_len = VIRTIO_VSOCK_DEFAULT_RX_BUF_SIZE; 180 struct virtio_vsock_pkt *pkt; 181 struct scatterlist hdr, buf, *sgs[2]; 182 struct virtqueue *vq; 183 int ret; 184 185 vq = vsock->vqs[VSOCK_VQ_RX]; 186 187 do { 188 pkt = kzalloc(sizeof(*pkt), GFP_KERNEL); 189 if (!pkt) 190 break; 191 192 pkt->buf = kmalloc(buf_len, GFP_KERNEL); 193 if (!pkt->buf) { 194 virtio_transport_free_pkt(pkt); 195 break; 196 } 197 198 pkt->len = buf_len; 199 200 sg_init_one(&hdr, &pkt->hdr, sizeof(pkt->hdr)); 201 sgs[0] = &hdr; 202 203 sg_init_one(&buf, pkt->buf, buf_len); 204 sgs[1] = &buf; 205 ret = virtqueue_add_sgs(vq, sgs, 0, 2, pkt, GFP_KERNEL); 206 if (ret) { 207 virtio_transport_free_pkt(pkt); 208 break; 209 } 210 vsock->rx_buf_nr++; 211 } while (vq->num_free); 212 if (vsock->rx_buf_nr > vsock->rx_buf_max_nr) 213 vsock->rx_buf_max_nr = vsock->rx_buf_nr; 214 virtqueue_kick(vq); 215 } 216 217 static void virtio_transport_tx_work(struct work_struct *work) 218 { 219 struct virtio_vsock *vsock = 220 container_of(work, struct virtio_vsock, tx_work); 221 struct virtqueue *vq; 222 bool added = false; 223 224 vq = vsock->vqs[VSOCK_VQ_TX]; 225 mutex_lock(&vsock->tx_lock); 226 do { 227 struct virtio_vsock_pkt *pkt; 228 unsigned int len; 229 230 virtqueue_disable_cb(vq); 231 while ((pkt = virtqueue_get_buf(vq, &len)) != NULL) { 232 virtio_transport_free_pkt(pkt); 233 added = true; 234 } 235 } while (!virtqueue_enable_cb(vq)); 236 mutex_unlock(&vsock->tx_lock); 237 238 if (added) 239 queue_work(virtio_vsock_workqueue, &vsock->send_pkt_work); 240 } 241 242 /* Is there space left for replies to rx packets? */ 243 static bool virtio_transport_more_replies(struct virtio_vsock *vsock) 244 { 245 struct virtqueue *vq = vsock->vqs[VSOCK_VQ_RX]; 246 int val; 247 248 smp_rmb(); /* paired with atomic_inc() and atomic_dec_return() */ 249 val = atomic_read(&vsock->queued_replies); 250 251 return val < virtqueue_get_vring_size(vq); 252 } 253 254 static void virtio_transport_rx_work(struct work_struct *work) 255 { 256 struct virtio_vsock *vsock = 257 container_of(work, struct virtio_vsock, rx_work); 258 struct virtqueue *vq; 259 260 vq = vsock->vqs[VSOCK_VQ_RX]; 261 262 mutex_lock(&vsock->rx_lock); 263 264 do { 265 virtqueue_disable_cb(vq); 266 for (;;) { 267 struct virtio_vsock_pkt *pkt; 268 unsigned int len; 269 270 if (!virtio_transport_more_replies(vsock)) { 271 /* Stop rx until the device processes already 272 * pending replies. Leave rx virtqueue 273 * callbacks disabled. 274 */ 275 goto out; 276 } 277 278 pkt = virtqueue_get_buf(vq, &len); 279 if (!pkt) { 280 break; 281 } 282 283 vsock->rx_buf_nr--; 284 285 /* Drop short/long packets */ 286 if (unlikely(len < sizeof(pkt->hdr) || 287 len > sizeof(pkt->hdr) + pkt->len)) { 288 virtio_transport_free_pkt(pkt); 289 continue; 290 } 291 292 pkt->len = len - sizeof(pkt->hdr); 293 virtio_transport_recv_pkt(pkt); 294 } 295 } while (!virtqueue_enable_cb(vq)); 296 297 out: 298 if (vsock->rx_buf_nr < vsock->rx_buf_max_nr / 2) 299 virtio_vsock_rx_fill(vsock); 300 mutex_unlock(&vsock->rx_lock); 301 } 302 303 /* event_lock must be held */ 304 static int virtio_vsock_event_fill_one(struct virtio_vsock *vsock, 305 struct virtio_vsock_event *event) 306 { 307 struct scatterlist sg; 308 struct virtqueue *vq; 309 310 vq = vsock->vqs[VSOCK_VQ_EVENT]; 311 312 sg_init_one(&sg, event, sizeof(*event)); 313 314 return virtqueue_add_inbuf(vq, &sg, 1, event, GFP_KERNEL); 315 } 316 317 /* event_lock must be held */ 318 static void virtio_vsock_event_fill(struct virtio_vsock *vsock) 319 { 320 size_t i; 321 322 for (i = 0; i < ARRAY_SIZE(vsock->event_list); i++) { 323 struct virtio_vsock_event *event = &vsock->event_list[i]; 324 325 virtio_vsock_event_fill_one(vsock, event); 326 } 327 328 virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]); 329 } 330 331 static void virtio_vsock_reset_sock(struct sock *sk) 332 { 333 lock_sock(sk); 334 sk->sk_state = SS_UNCONNECTED; 335 sk->sk_err = ECONNRESET; 336 sk->sk_error_report(sk); 337 release_sock(sk); 338 } 339 340 static void virtio_vsock_update_guest_cid(struct virtio_vsock *vsock) 341 { 342 struct virtio_device *vdev = vsock->vdev; 343 u64 guest_cid; 344 345 vdev->config->get(vdev, offsetof(struct virtio_vsock_config, guest_cid), 346 &guest_cid, sizeof(guest_cid)); 347 vsock->guest_cid = le64_to_cpu(guest_cid); 348 } 349 350 /* event_lock must be held */ 351 static void virtio_vsock_event_handle(struct virtio_vsock *vsock, 352 struct virtio_vsock_event *event) 353 { 354 switch (le32_to_cpu(event->id)) { 355 case VIRTIO_VSOCK_EVENT_TRANSPORT_RESET: 356 virtio_vsock_update_guest_cid(vsock); 357 vsock_for_each_connected_socket(virtio_vsock_reset_sock); 358 break; 359 } 360 } 361 362 static void virtio_transport_event_work(struct work_struct *work) 363 { 364 struct virtio_vsock *vsock = 365 container_of(work, struct virtio_vsock, event_work); 366 struct virtqueue *vq; 367 368 vq = vsock->vqs[VSOCK_VQ_EVENT]; 369 370 mutex_lock(&vsock->event_lock); 371 372 do { 373 struct virtio_vsock_event *event; 374 unsigned int len; 375 376 virtqueue_disable_cb(vq); 377 while ((event = virtqueue_get_buf(vq, &len)) != NULL) { 378 if (len == sizeof(*event)) 379 virtio_vsock_event_handle(vsock, event); 380 381 virtio_vsock_event_fill_one(vsock, event); 382 } 383 } while (!virtqueue_enable_cb(vq)); 384 385 virtqueue_kick(vsock->vqs[VSOCK_VQ_EVENT]); 386 387 mutex_unlock(&vsock->event_lock); 388 } 389 390 static void virtio_vsock_event_done(struct virtqueue *vq) 391 { 392 struct virtio_vsock *vsock = vq->vdev->priv; 393 394 if (!vsock) 395 return; 396 queue_work(virtio_vsock_workqueue, &vsock->event_work); 397 } 398 399 static void virtio_vsock_tx_done(struct virtqueue *vq) 400 { 401 struct virtio_vsock *vsock = vq->vdev->priv; 402 403 if (!vsock) 404 return; 405 queue_work(virtio_vsock_workqueue, &vsock->tx_work); 406 } 407 408 static void virtio_vsock_rx_done(struct virtqueue *vq) 409 { 410 struct virtio_vsock *vsock = vq->vdev->priv; 411 412 if (!vsock) 413 return; 414 queue_work(virtio_vsock_workqueue, &vsock->rx_work); 415 } 416 417 static struct virtio_transport virtio_transport = { 418 .transport = { 419 .get_local_cid = virtio_transport_get_local_cid, 420 421 .init = virtio_transport_do_socket_init, 422 .destruct = virtio_transport_destruct, 423 .release = virtio_transport_release, 424 .connect = virtio_transport_connect, 425 .shutdown = virtio_transport_shutdown, 426 427 .dgram_bind = virtio_transport_dgram_bind, 428 .dgram_dequeue = virtio_transport_dgram_dequeue, 429 .dgram_enqueue = virtio_transport_dgram_enqueue, 430 .dgram_allow = virtio_transport_dgram_allow, 431 432 .stream_dequeue = virtio_transport_stream_dequeue, 433 .stream_enqueue = virtio_transport_stream_enqueue, 434 .stream_has_data = virtio_transport_stream_has_data, 435 .stream_has_space = virtio_transport_stream_has_space, 436 .stream_rcvhiwat = virtio_transport_stream_rcvhiwat, 437 .stream_is_active = virtio_transport_stream_is_active, 438 .stream_allow = virtio_transport_stream_allow, 439 440 .notify_poll_in = virtio_transport_notify_poll_in, 441 .notify_poll_out = virtio_transport_notify_poll_out, 442 .notify_recv_init = virtio_transport_notify_recv_init, 443 .notify_recv_pre_block = virtio_transport_notify_recv_pre_block, 444 .notify_recv_pre_dequeue = virtio_transport_notify_recv_pre_dequeue, 445 .notify_recv_post_dequeue = virtio_transport_notify_recv_post_dequeue, 446 .notify_send_init = virtio_transport_notify_send_init, 447 .notify_send_pre_block = virtio_transport_notify_send_pre_block, 448 .notify_send_pre_enqueue = virtio_transport_notify_send_pre_enqueue, 449 .notify_send_post_enqueue = virtio_transport_notify_send_post_enqueue, 450 451 .set_buffer_size = virtio_transport_set_buffer_size, 452 .set_min_buffer_size = virtio_transport_set_min_buffer_size, 453 .set_max_buffer_size = virtio_transport_set_max_buffer_size, 454 .get_buffer_size = virtio_transport_get_buffer_size, 455 .get_min_buffer_size = virtio_transport_get_min_buffer_size, 456 .get_max_buffer_size = virtio_transport_get_max_buffer_size, 457 }, 458 459 .send_pkt = virtio_transport_send_pkt, 460 }; 461 462 static int virtio_vsock_probe(struct virtio_device *vdev) 463 { 464 vq_callback_t *callbacks[] = { 465 virtio_vsock_rx_done, 466 virtio_vsock_tx_done, 467 virtio_vsock_event_done, 468 }; 469 static const char * const names[] = { 470 "rx", 471 "tx", 472 "event", 473 }; 474 struct virtio_vsock *vsock = NULL; 475 int ret; 476 477 ret = mutex_lock_interruptible(&the_virtio_vsock_mutex); 478 if (ret) 479 return ret; 480 481 /* Only one virtio-vsock device per guest is supported */ 482 if (the_virtio_vsock) { 483 ret = -EBUSY; 484 goto out; 485 } 486 487 vsock = kzalloc(sizeof(*vsock), GFP_KERNEL); 488 if (!vsock) { 489 ret = -ENOMEM; 490 goto out; 491 } 492 493 vsock->vdev = vdev; 494 495 ret = vsock->vdev->config->find_vqs(vsock->vdev, VSOCK_VQ_MAX, 496 vsock->vqs, callbacks, names); 497 if (ret < 0) 498 goto out; 499 500 virtio_vsock_update_guest_cid(vsock); 501 502 ret = vsock_core_init(&virtio_transport.transport); 503 if (ret < 0) 504 goto out_vqs; 505 506 vsock->rx_buf_nr = 0; 507 vsock->rx_buf_max_nr = 0; 508 atomic_set(&vsock->queued_replies, 0); 509 510 vdev->priv = vsock; 511 the_virtio_vsock = vsock; 512 mutex_init(&vsock->tx_lock); 513 mutex_init(&vsock->rx_lock); 514 mutex_init(&vsock->event_lock); 515 spin_lock_init(&vsock->send_pkt_list_lock); 516 INIT_LIST_HEAD(&vsock->send_pkt_list); 517 INIT_WORK(&vsock->rx_work, virtio_transport_rx_work); 518 INIT_WORK(&vsock->tx_work, virtio_transport_tx_work); 519 INIT_WORK(&vsock->event_work, virtio_transport_event_work); 520 INIT_WORK(&vsock->send_pkt_work, virtio_transport_send_pkt_work); 521 522 mutex_lock(&vsock->rx_lock); 523 virtio_vsock_rx_fill(vsock); 524 mutex_unlock(&vsock->rx_lock); 525 526 mutex_lock(&vsock->event_lock); 527 virtio_vsock_event_fill(vsock); 528 mutex_unlock(&vsock->event_lock); 529 530 mutex_unlock(&the_virtio_vsock_mutex); 531 return 0; 532 533 out_vqs: 534 vsock->vdev->config->del_vqs(vsock->vdev); 535 out: 536 kfree(vsock); 537 mutex_unlock(&the_virtio_vsock_mutex); 538 return ret; 539 } 540 541 static void virtio_vsock_remove(struct virtio_device *vdev) 542 { 543 struct virtio_vsock *vsock = vdev->priv; 544 struct virtio_vsock_pkt *pkt; 545 546 flush_work(&vsock->rx_work); 547 flush_work(&vsock->tx_work); 548 flush_work(&vsock->event_work); 549 flush_work(&vsock->send_pkt_work); 550 551 vdev->config->reset(vdev); 552 553 mutex_lock(&vsock->rx_lock); 554 while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_RX]))) 555 virtio_transport_free_pkt(pkt); 556 mutex_unlock(&vsock->rx_lock); 557 558 mutex_lock(&vsock->tx_lock); 559 while ((pkt = virtqueue_detach_unused_buf(vsock->vqs[VSOCK_VQ_TX]))) 560 virtio_transport_free_pkt(pkt); 561 mutex_unlock(&vsock->tx_lock); 562 563 spin_lock_bh(&vsock->send_pkt_list_lock); 564 while (!list_empty(&vsock->send_pkt_list)) { 565 pkt = list_first_entry(&vsock->send_pkt_list, 566 struct virtio_vsock_pkt, list); 567 list_del(&pkt->list); 568 virtio_transport_free_pkt(pkt); 569 } 570 spin_unlock_bh(&vsock->send_pkt_list_lock); 571 572 mutex_lock(&the_virtio_vsock_mutex); 573 the_virtio_vsock = NULL; 574 vsock_core_exit(); 575 mutex_unlock(&the_virtio_vsock_mutex); 576 577 vdev->config->del_vqs(vdev); 578 579 kfree(vsock); 580 } 581 582 static struct virtio_device_id id_table[] = { 583 { VIRTIO_ID_VSOCK, VIRTIO_DEV_ANY_ID }, 584 { 0 }, 585 }; 586 587 static unsigned int features[] = { 588 }; 589 590 static struct virtio_driver virtio_vsock_driver = { 591 .feature_table = features, 592 .feature_table_size = ARRAY_SIZE(features), 593 .driver.name = KBUILD_MODNAME, 594 .driver.owner = THIS_MODULE, 595 .id_table = id_table, 596 .probe = virtio_vsock_probe, 597 .remove = virtio_vsock_remove, 598 }; 599 600 static int __init virtio_vsock_init(void) 601 { 602 int ret; 603 604 virtio_vsock_workqueue = alloc_workqueue("virtio_vsock", 0, 0); 605 if (!virtio_vsock_workqueue) 606 return -ENOMEM; 607 ret = register_virtio_driver(&virtio_vsock_driver); 608 if (ret) 609 destroy_workqueue(virtio_vsock_workqueue); 610 return ret; 611 } 612 613 static void __exit virtio_vsock_exit(void) 614 { 615 unregister_virtio_driver(&virtio_vsock_driver); 616 destroy_workqueue(virtio_vsock_workqueue); 617 } 618 619 module_init(virtio_vsock_init); 620 module_exit(virtio_vsock_exit); 621 MODULE_LICENSE("GPL v2"); 622 MODULE_AUTHOR("Asias He"); 623 MODULE_DESCRIPTION("virtio transport for vsock"); 624 MODULE_DEVICE_TABLE(virtio, id_table); 625