1 // SPDX-License-Identifier: GPL-2.0-only 2 /* Copyright (C) 2009 Red Hat, Inc. 3 * Copyright (C) 2006 Rusty Russell IBM Corporation 4 * 5 * Author: Michael S. Tsirkin <mst@redhat.com> 6 * 7 * Inspiration, some code, and most witty comments come from 8 * Documentation/virtual/lguest/lguest.c, by Rusty Russell 9 * 10 * Generic code for virtio server in host kernel. 11 */ 12 13 #include <linux/eventfd.h> 14 #include <linux/vhost.h> 15 #include <linux/uio.h> 16 #include <linux/mm.h> 17 #include <linux/miscdevice.h> 18 #include <linux/mutex.h> 19 #include <linux/poll.h> 20 #include <linux/file.h> 21 #include <linux/highmem.h> 22 #include <linux/slab.h> 23 #include <linux/vmalloc.h> 24 #include <linux/kthread.h> 25 #include <linux/module.h> 26 #include <linux/sort.h> 27 #include <linux/sched/mm.h> 28 #include <linux/sched/signal.h> 29 #include <linux/sched/vhost_task.h> 30 #include <linux/interval_tree_generic.h> 31 #include <linux/nospec.h> 32 #include <linux/kcov.h> 33 34 #include "vhost.h" 35 36 static ushort max_mem_regions = 64; 37 module_param(max_mem_regions, ushort, 0444); 38 MODULE_PARM_DESC(max_mem_regions, 39 "Maximum number of memory regions in memory map. (default: 64)"); 40 static int max_iotlb_entries = 2048; 41 module_param(max_iotlb_entries, int, 0444); 42 MODULE_PARM_DESC(max_iotlb_entries, 43 "Maximum number of iotlb entries. (default: 2048)"); 44 45 enum { 46 VHOST_MEMORY_F_LOG = 0x1, 47 }; 48 49 #define vhost_used_event(vq) ((__virtio16 __user *)&vq->avail->ring[vq->num]) 50 #define vhost_avail_event(vq) ((__virtio16 __user *)&vq->used->ring[vq->num]) 51 52 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY 53 static void vhost_disable_cross_endian(struct vhost_virtqueue *vq) 54 { 55 vq->user_be = !virtio_legacy_is_little_endian(); 56 } 57 58 static void vhost_enable_cross_endian_big(struct vhost_virtqueue *vq) 59 { 60 vq->user_be = true; 61 } 62 63 static void vhost_enable_cross_endian_little(struct vhost_virtqueue *vq) 64 { 65 vq->user_be = false; 66 } 67 68 static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp) 69 { 70 struct vhost_vring_state s; 71 72 if (vq->private_data) 73 return -EBUSY; 74 75 if (copy_from_user(&s, argp, sizeof(s))) 76 return -EFAULT; 77 78 if (s.num != VHOST_VRING_LITTLE_ENDIAN && 79 s.num != VHOST_VRING_BIG_ENDIAN) 80 return -EINVAL; 81 82 if (s.num == VHOST_VRING_BIG_ENDIAN) 83 vhost_enable_cross_endian_big(vq); 84 else 85 vhost_enable_cross_endian_little(vq); 86 87 return 0; 88 } 89 90 static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx, 91 int __user *argp) 92 { 93 struct vhost_vring_state s = { 94 .index = idx, 95 .num = vq->user_be 96 }; 97 98 if (copy_to_user(argp, &s, sizeof(s))) 99 return -EFAULT; 100 101 return 0; 102 } 103 104 static void vhost_init_is_le(struct vhost_virtqueue *vq) 105 { 106 /* Note for legacy virtio: user_be is initialized at reset time 107 * according to the host endianness. If userspace does not set an 108 * explicit endianness, the default behavior is native endian, as 109 * expected by legacy virtio. 110 */ 111 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1) || !vq->user_be; 112 } 113 #else 114 static void vhost_disable_cross_endian(struct vhost_virtqueue *vq) 115 { 116 } 117 118 static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp) 119 { 120 return -ENOIOCTLCMD; 121 } 122 123 static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx, 124 int __user *argp) 125 { 126 return -ENOIOCTLCMD; 127 } 128 129 static void vhost_init_is_le(struct vhost_virtqueue *vq) 130 { 131 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1) 132 || virtio_legacy_is_little_endian(); 133 } 134 #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */ 135 136 static void vhost_reset_is_le(struct vhost_virtqueue *vq) 137 { 138 vhost_init_is_le(vq); 139 } 140 141 struct vhost_flush_struct { 142 struct vhost_work work; 143 struct completion wait_event; 144 }; 145 146 static void vhost_flush_work(struct vhost_work *work) 147 { 148 struct vhost_flush_struct *s; 149 150 s = container_of(work, struct vhost_flush_struct, work); 151 complete(&s->wait_event); 152 } 153 154 static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh, 155 poll_table *pt) 156 { 157 struct vhost_poll *poll; 158 159 poll = container_of(pt, struct vhost_poll, table); 160 poll->wqh = wqh; 161 add_wait_queue(wqh, &poll->wait); 162 } 163 164 static int vhost_poll_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync, 165 void *key) 166 { 167 struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait); 168 struct vhost_work *work = &poll->work; 169 170 if (!(key_to_poll(key) & poll->mask)) 171 return 0; 172 173 if (!poll->dev->use_worker) 174 work->fn(work); 175 else 176 vhost_poll_queue(poll); 177 178 return 0; 179 } 180 181 void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn) 182 { 183 clear_bit(VHOST_WORK_QUEUED, &work->flags); 184 work->fn = fn; 185 } 186 EXPORT_SYMBOL_GPL(vhost_work_init); 187 188 /* Init poll structure */ 189 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn, 190 __poll_t mask, struct vhost_dev *dev) 191 { 192 init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup); 193 init_poll_funcptr(&poll->table, vhost_poll_func); 194 poll->mask = mask; 195 poll->dev = dev; 196 poll->wqh = NULL; 197 198 vhost_work_init(&poll->work, fn); 199 } 200 EXPORT_SYMBOL_GPL(vhost_poll_init); 201 202 /* Start polling a file. We add ourselves to file's wait queue. The caller must 203 * keep a reference to a file until after vhost_poll_stop is called. */ 204 int vhost_poll_start(struct vhost_poll *poll, struct file *file) 205 { 206 __poll_t mask; 207 208 if (poll->wqh) 209 return 0; 210 211 mask = vfs_poll(file, &poll->table); 212 if (mask) 213 vhost_poll_wakeup(&poll->wait, 0, 0, poll_to_key(mask)); 214 if (mask & EPOLLERR) { 215 vhost_poll_stop(poll); 216 return -EINVAL; 217 } 218 219 return 0; 220 } 221 EXPORT_SYMBOL_GPL(vhost_poll_start); 222 223 /* Stop polling a file. After this function returns, it becomes safe to drop the 224 * file reference. You must also flush afterwards. */ 225 void vhost_poll_stop(struct vhost_poll *poll) 226 { 227 if (poll->wqh) { 228 remove_wait_queue(poll->wqh, &poll->wait); 229 poll->wqh = NULL; 230 } 231 } 232 EXPORT_SYMBOL_GPL(vhost_poll_stop); 233 234 void vhost_dev_flush(struct vhost_dev *dev) 235 { 236 struct vhost_flush_struct flush; 237 238 if (dev->worker) { 239 init_completion(&flush.wait_event); 240 vhost_work_init(&flush.work, vhost_flush_work); 241 242 vhost_work_queue(dev, &flush.work); 243 wait_for_completion(&flush.wait_event); 244 } 245 } 246 EXPORT_SYMBOL_GPL(vhost_dev_flush); 247 248 void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work) 249 { 250 if (!dev->worker) 251 return; 252 253 if (!test_and_set_bit(VHOST_WORK_QUEUED, &work->flags)) { 254 /* We can only add the work to the list after we're 255 * sure it was not in the list. 256 * test_and_set_bit() implies a memory barrier. 257 */ 258 llist_add(&work->node, &dev->worker->work_list); 259 wake_up_process(dev->worker->vtsk->task); 260 } 261 } 262 EXPORT_SYMBOL_GPL(vhost_work_queue); 263 264 /* A lockless hint for busy polling code to exit the loop */ 265 bool vhost_has_work(struct vhost_dev *dev) 266 { 267 return dev->worker && !llist_empty(&dev->worker->work_list); 268 } 269 EXPORT_SYMBOL_GPL(vhost_has_work); 270 271 void vhost_poll_queue(struct vhost_poll *poll) 272 { 273 vhost_work_queue(poll->dev, &poll->work); 274 } 275 EXPORT_SYMBOL_GPL(vhost_poll_queue); 276 277 static void __vhost_vq_meta_reset(struct vhost_virtqueue *vq) 278 { 279 int j; 280 281 for (j = 0; j < VHOST_NUM_ADDRS; j++) 282 vq->meta_iotlb[j] = NULL; 283 } 284 285 static void vhost_vq_meta_reset(struct vhost_dev *d) 286 { 287 int i; 288 289 for (i = 0; i < d->nvqs; ++i) 290 __vhost_vq_meta_reset(d->vqs[i]); 291 } 292 293 static void vhost_vring_call_reset(struct vhost_vring_call *call_ctx) 294 { 295 call_ctx->ctx = NULL; 296 memset(&call_ctx->producer, 0x0, sizeof(struct irq_bypass_producer)); 297 } 298 299 bool vhost_vq_is_setup(struct vhost_virtqueue *vq) 300 { 301 return vq->avail && vq->desc && vq->used && vhost_vq_access_ok(vq); 302 } 303 EXPORT_SYMBOL_GPL(vhost_vq_is_setup); 304 305 static void vhost_vq_reset(struct vhost_dev *dev, 306 struct vhost_virtqueue *vq) 307 { 308 vq->num = 1; 309 vq->desc = NULL; 310 vq->avail = NULL; 311 vq->used = NULL; 312 vq->last_avail_idx = 0; 313 vq->avail_idx = 0; 314 vq->last_used_idx = 0; 315 vq->signalled_used = 0; 316 vq->signalled_used_valid = false; 317 vq->used_flags = 0; 318 vq->log_used = false; 319 vq->log_addr = -1ull; 320 vq->private_data = NULL; 321 vq->acked_features = 0; 322 vq->acked_backend_features = 0; 323 vq->log_base = NULL; 324 vq->error_ctx = NULL; 325 vq->kick = NULL; 326 vq->log_ctx = NULL; 327 vhost_disable_cross_endian(vq); 328 vhost_reset_is_le(vq); 329 vq->busyloop_timeout = 0; 330 vq->umem = NULL; 331 vq->iotlb = NULL; 332 vhost_vring_call_reset(&vq->call_ctx); 333 __vhost_vq_meta_reset(vq); 334 } 335 336 static int vhost_worker(void *data) 337 { 338 struct vhost_worker *worker = data; 339 struct vhost_work *work, *work_next; 340 struct llist_node *node; 341 342 for (;;) { 343 /* mb paired w/ kthread_stop */ 344 set_current_state(TASK_INTERRUPTIBLE); 345 346 if (vhost_task_should_stop(worker->vtsk)) { 347 __set_current_state(TASK_RUNNING); 348 break; 349 } 350 351 node = llist_del_all(&worker->work_list); 352 if (!node) 353 schedule(); 354 355 node = llist_reverse_order(node); 356 /* make sure flag is seen after deletion */ 357 smp_wmb(); 358 llist_for_each_entry_safe(work, work_next, node, node) { 359 clear_bit(VHOST_WORK_QUEUED, &work->flags); 360 __set_current_state(TASK_RUNNING); 361 kcov_remote_start_common(worker->kcov_handle); 362 work->fn(work); 363 kcov_remote_stop(); 364 if (need_resched()) 365 schedule(); 366 } 367 } 368 369 return 0; 370 } 371 372 static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq) 373 { 374 kfree(vq->indirect); 375 vq->indirect = NULL; 376 kfree(vq->log); 377 vq->log = NULL; 378 kfree(vq->heads); 379 vq->heads = NULL; 380 } 381 382 /* Helper to allocate iovec buffers for all vqs. */ 383 static long vhost_dev_alloc_iovecs(struct vhost_dev *dev) 384 { 385 struct vhost_virtqueue *vq; 386 int i; 387 388 for (i = 0; i < dev->nvqs; ++i) { 389 vq = dev->vqs[i]; 390 vq->indirect = kmalloc_array(UIO_MAXIOV, 391 sizeof(*vq->indirect), 392 GFP_KERNEL); 393 vq->log = kmalloc_array(dev->iov_limit, sizeof(*vq->log), 394 GFP_KERNEL); 395 vq->heads = kmalloc_array(dev->iov_limit, sizeof(*vq->heads), 396 GFP_KERNEL); 397 if (!vq->indirect || !vq->log || !vq->heads) 398 goto err_nomem; 399 } 400 return 0; 401 402 err_nomem: 403 for (; i >= 0; --i) 404 vhost_vq_free_iovecs(dev->vqs[i]); 405 return -ENOMEM; 406 } 407 408 static void vhost_dev_free_iovecs(struct vhost_dev *dev) 409 { 410 int i; 411 412 for (i = 0; i < dev->nvqs; ++i) 413 vhost_vq_free_iovecs(dev->vqs[i]); 414 } 415 416 bool vhost_exceeds_weight(struct vhost_virtqueue *vq, 417 int pkts, int total_len) 418 { 419 struct vhost_dev *dev = vq->dev; 420 421 if ((dev->byte_weight && total_len >= dev->byte_weight) || 422 pkts >= dev->weight) { 423 vhost_poll_queue(&vq->poll); 424 return true; 425 } 426 427 return false; 428 } 429 EXPORT_SYMBOL_GPL(vhost_exceeds_weight); 430 431 static size_t vhost_get_avail_size(struct vhost_virtqueue *vq, 432 unsigned int num) 433 { 434 size_t event __maybe_unused = 435 vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; 436 437 return sizeof(*vq->avail) + 438 sizeof(*vq->avail->ring) * num + event; 439 } 440 441 static size_t vhost_get_used_size(struct vhost_virtqueue *vq, 442 unsigned int num) 443 { 444 size_t event __maybe_unused = 445 vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; 446 447 return sizeof(*vq->used) + 448 sizeof(*vq->used->ring) * num + event; 449 } 450 451 static size_t vhost_get_desc_size(struct vhost_virtqueue *vq, 452 unsigned int num) 453 { 454 return sizeof(*vq->desc) * num; 455 } 456 457 void vhost_dev_init(struct vhost_dev *dev, 458 struct vhost_virtqueue **vqs, int nvqs, 459 int iov_limit, int weight, int byte_weight, 460 bool use_worker, 461 int (*msg_handler)(struct vhost_dev *dev, u32 asid, 462 struct vhost_iotlb_msg *msg)) 463 { 464 struct vhost_virtqueue *vq; 465 int i; 466 467 dev->vqs = vqs; 468 dev->nvqs = nvqs; 469 mutex_init(&dev->mutex); 470 dev->log_ctx = NULL; 471 dev->umem = NULL; 472 dev->iotlb = NULL; 473 dev->mm = NULL; 474 dev->worker = NULL; 475 dev->iov_limit = iov_limit; 476 dev->weight = weight; 477 dev->byte_weight = byte_weight; 478 dev->use_worker = use_worker; 479 dev->msg_handler = msg_handler; 480 init_waitqueue_head(&dev->wait); 481 INIT_LIST_HEAD(&dev->read_list); 482 INIT_LIST_HEAD(&dev->pending_list); 483 spin_lock_init(&dev->iotlb_lock); 484 485 486 for (i = 0; i < dev->nvqs; ++i) { 487 vq = dev->vqs[i]; 488 vq->log = NULL; 489 vq->indirect = NULL; 490 vq->heads = NULL; 491 vq->dev = dev; 492 mutex_init(&vq->mutex); 493 vhost_vq_reset(dev, vq); 494 if (vq->handle_kick) 495 vhost_poll_init(&vq->poll, vq->handle_kick, 496 EPOLLIN, dev); 497 } 498 } 499 EXPORT_SYMBOL_GPL(vhost_dev_init); 500 501 /* Caller should have device mutex */ 502 long vhost_dev_check_owner(struct vhost_dev *dev) 503 { 504 /* Are you the owner? If not, I don't think you mean to do that */ 505 return dev->mm == current->mm ? 0 : -EPERM; 506 } 507 EXPORT_SYMBOL_GPL(vhost_dev_check_owner); 508 509 /* Caller should have device mutex */ 510 bool vhost_dev_has_owner(struct vhost_dev *dev) 511 { 512 return dev->mm; 513 } 514 EXPORT_SYMBOL_GPL(vhost_dev_has_owner); 515 516 static void vhost_attach_mm(struct vhost_dev *dev) 517 { 518 /* No owner, become one */ 519 if (dev->use_worker) { 520 dev->mm = get_task_mm(current); 521 } else { 522 /* vDPA device does not use worker thead, so there's 523 * no need to hold the address space for mm. This help 524 * to avoid deadlock in the case of mmap() which may 525 * held the refcnt of the file and depends on release 526 * method to remove vma. 527 */ 528 dev->mm = current->mm; 529 mmgrab(dev->mm); 530 } 531 } 532 533 static void vhost_detach_mm(struct vhost_dev *dev) 534 { 535 if (!dev->mm) 536 return; 537 538 if (dev->use_worker) 539 mmput(dev->mm); 540 else 541 mmdrop(dev->mm); 542 543 dev->mm = NULL; 544 } 545 546 static void vhost_worker_free(struct vhost_dev *dev) 547 { 548 struct vhost_worker *worker = dev->worker; 549 550 if (!worker) 551 return; 552 553 dev->worker = NULL; 554 WARN_ON(!llist_empty(&worker->work_list)); 555 vhost_task_stop(worker->vtsk); 556 kfree(worker); 557 } 558 559 static int vhost_worker_create(struct vhost_dev *dev) 560 { 561 struct vhost_worker *worker; 562 struct vhost_task *vtsk; 563 char name[TASK_COMM_LEN]; 564 int ret; 565 566 worker = kzalloc(sizeof(*worker), GFP_KERNEL_ACCOUNT); 567 if (!worker) 568 return -ENOMEM; 569 570 dev->worker = worker; 571 worker->kcov_handle = kcov_common_handle(); 572 init_llist_head(&worker->work_list); 573 snprintf(name, sizeof(name), "vhost-%d", current->pid); 574 575 vtsk = vhost_task_create(vhost_worker, worker, name); 576 if (!vtsk) { 577 ret = -ENOMEM; 578 goto free_worker; 579 } 580 581 worker->vtsk = vtsk; 582 vhost_task_start(vtsk); 583 return 0; 584 585 free_worker: 586 kfree(worker); 587 dev->worker = NULL; 588 return ret; 589 } 590 591 /* Caller should have device mutex */ 592 long vhost_dev_set_owner(struct vhost_dev *dev) 593 { 594 int err; 595 596 /* Is there an owner already? */ 597 if (vhost_dev_has_owner(dev)) { 598 err = -EBUSY; 599 goto err_mm; 600 } 601 602 vhost_attach_mm(dev); 603 604 if (dev->use_worker) { 605 err = vhost_worker_create(dev); 606 if (err) 607 goto err_worker; 608 } 609 610 err = vhost_dev_alloc_iovecs(dev); 611 if (err) 612 goto err_iovecs; 613 614 return 0; 615 err_iovecs: 616 vhost_worker_free(dev); 617 err_worker: 618 vhost_detach_mm(dev); 619 err_mm: 620 return err; 621 } 622 EXPORT_SYMBOL_GPL(vhost_dev_set_owner); 623 624 static struct vhost_iotlb *iotlb_alloc(void) 625 { 626 return vhost_iotlb_alloc(max_iotlb_entries, 627 VHOST_IOTLB_FLAG_RETIRE); 628 } 629 630 struct vhost_iotlb *vhost_dev_reset_owner_prepare(void) 631 { 632 return iotlb_alloc(); 633 } 634 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare); 635 636 /* Caller should have device mutex */ 637 void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_iotlb *umem) 638 { 639 int i; 640 641 vhost_dev_cleanup(dev); 642 643 dev->umem = umem; 644 /* We don't need VQ locks below since vhost_dev_cleanup makes sure 645 * VQs aren't running. 646 */ 647 for (i = 0; i < dev->nvqs; ++i) 648 dev->vqs[i]->umem = umem; 649 } 650 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner); 651 652 void vhost_dev_stop(struct vhost_dev *dev) 653 { 654 int i; 655 656 for (i = 0; i < dev->nvqs; ++i) { 657 if (dev->vqs[i]->kick && dev->vqs[i]->handle_kick) 658 vhost_poll_stop(&dev->vqs[i]->poll); 659 } 660 661 vhost_dev_flush(dev); 662 } 663 EXPORT_SYMBOL_GPL(vhost_dev_stop); 664 665 void vhost_clear_msg(struct vhost_dev *dev) 666 { 667 struct vhost_msg_node *node, *n; 668 669 spin_lock(&dev->iotlb_lock); 670 671 list_for_each_entry_safe(node, n, &dev->read_list, node) { 672 list_del(&node->node); 673 kfree(node); 674 } 675 676 list_for_each_entry_safe(node, n, &dev->pending_list, node) { 677 list_del(&node->node); 678 kfree(node); 679 } 680 681 spin_unlock(&dev->iotlb_lock); 682 } 683 EXPORT_SYMBOL_GPL(vhost_clear_msg); 684 685 void vhost_dev_cleanup(struct vhost_dev *dev) 686 { 687 int i; 688 689 for (i = 0; i < dev->nvqs; ++i) { 690 if (dev->vqs[i]->error_ctx) 691 eventfd_ctx_put(dev->vqs[i]->error_ctx); 692 if (dev->vqs[i]->kick) 693 fput(dev->vqs[i]->kick); 694 if (dev->vqs[i]->call_ctx.ctx) 695 eventfd_ctx_put(dev->vqs[i]->call_ctx.ctx); 696 vhost_vq_reset(dev, dev->vqs[i]); 697 } 698 vhost_dev_free_iovecs(dev); 699 if (dev->log_ctx) 700 eventfd_ctx_put(dev->log_ctx); 701 dev->log_ctx = NULL; 702 /* No one will access memory at this point */ 703 vhost_iotlb_free(dev->umem); 704 dev->umem = NULL; 705 vhost_iotlb_free(dev->iotlb); 706 dev->iotlb = NULL; 707 vhost_clear_msg(dev); 708 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM); 709 vhost_worker_free(dev); 710 vhost_detach_mm(dev); 711 } 712 EXPORT_SYMBOL_GPL(vhost_dev_cleanup); 713 714 static bool log_access_ok(void __user *log_base, u64 addr, unsigned long sz) 715 { 716 u64 a = addr / VHOST_PAGE_SIZE / 8; 717 718 /* Make sure 64 bit math will not overflow. */ 719 if (a > ULONG_MAX - (unsigned long)log_base || 720 a + (unsigned long)log_base > ULONG_MAX) 721 return false; 722 723 return access_ok(log_base + a, 724 (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8); 725 } 726 727 /* Make sure 64 bit math will not overflow. */ 728 static bool vhost_overflow(u64 uaddr, u64 size) 729 { 730 if (uaddr > ULONG_MAX || size > ULONG_MAX) 731 return true; 732 733 if (!size) 734 return false; 735 736 return uaddr > ULONG_MAX - size + 1; 737 } 738 739 /* Caller should have vq mutex and device mutex. */ 740 static bool vq_memory_access_ok(void __user *log_base, struct vhost_iotlb *umem, 741 int log_all) 742 { 743 struct vhost_iotlb_map *map; 744 745 if (!umem) 746 return false; 747 748 list_for_each_entry(map, &umem->list, link) { 749 unsigned long a = map->addr; 750 751 if (vhost_overflow(map->addr, map->size)) 752 return false; 753 754 755 if (!access_ok((void __user *)a, map->size)) 756 return false; 757 else if (log_all && !log_access_ok(log_base, 758 map->start, 759 map->size)) 760 return false; 761 } 762 return true; 763 } 764 765 static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq, 766 u64 addr, unsigned int size, 767 int type) 768 { 769 const struct vhost_iotlb_map *map = vq->meta_iotlb[type]; 770 771 if (!map) 772 return NULL; 773 774 return (void __user *)(uintptr_t)(map->addr + addr - map->start); 775 } 776 777 /* Can we switch to this memory table? */ 778 /* Caller should have device mutex but not vq mutex */ 779 static bool memory_access_ok(struct vhost_dev *d, struct vhost_iotlb *umem, 780 int log_all) 781 { 782 int i; 783 784 for (i = 0; i < d->nvqs; ++i) { 785 bool ok; 786 bool log; 787 788 mutex_lock(&d->vqs[i]->mutex); 789 log = log_all || vhost_has_feature(d->vqs[i], VHOST_F_LOG_ALL); 790 /* If ring is inactive, will check when it's enabled. */ 791 if (d->vqs[i]->private_data) 792 ok = vq_memory_access_ok(d->vqs[i]->log_base, 793 umem, log); 794 else 795 ok = true; 796 mutex_unlock(&d->vqs[i]->mutex); 797 if (!ok) 798 return false; 799 } 800 return true; 801 } 802 803 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len, 804 struct iovec iov[], int iov_size, int access); 805 806 static int vhost_copy_to_user(struct vhost_virtqueue *vq, void __user *to, 807 const void *from, unsigned size) 808 { 809 int ret; 810 811 if (!vq->iotlb) 812 return __copy_to_user(to, from, size); 813 else { 814 /* This function should be called after iotlb 815 * prefetch, which means we're sure that all vq 816 * could be access through iotlb. So -EAGAIN should 817 * not happen in this case. 818 */ 819 struct iov_iter t; 820 void __user *uaddr = vhost_vq_meta_fetch(vq, 821 (u64)(uintptr_t)to, size, 822 VHOST_ADDR_USED); 823 824 if (uaddr) 825 return __copy_to_user(uaddr, from, size); 826 827 ret = translate_desc(vq, (u64)(uintptr_t)to, size, vq->iotlb_iov, 828 ARRAY_SIZE(vq->iotlb_iov), 829 VHOST_ACCESS_WO); 830 if (ret < 0) 831 goto out; 832 iov_iter_init(&t, ITER_DEST, vq->iotlb_iov, ret, size); 833 ret = copy_to_iter(from, size, &t); 834 if (ret == size) 835 ret = 0; 836 } 837 out: 838 return ret; 839 } 840 841 static int vhost_copy_from_user(struct vhost_virtqueue *vq, void *to, 842 void __user *from, unsigned size) 843 { 844 int ret; 845 846 if (!vq->iotlb) 847 return __copy_from_user(to, from, size); 848 else { 849 /* This function should be called after iotlb 850 * prefetch, which means we're sure that vq 851 * could be access through iotlb. So -EAGAIN should 852 * not happen in this case. 853 */ 854 void __user *uaddr = vhost_vq_meta_fetch(vq, 855 (u64)(uintptr_t)from, size, 856 VHOST_ADDR_DESC); 857 struct iov_iter f; 858 859 if (uaddr) 860 return __copy_from_user(to, uaddr, size); 861 862 ret = translate_desc(vq, (u64)(uintptr_t)from, size, vq->iotlb_iov, 863 ARRAY_SIZE(vq->iotlb_iov), 864 VHOST_ACCESS_RO); 865 if (ret < 0) { 866 vq_err(vq, "IOTLB translation failure: uaddr " 867 "%p size 0x%llx\n", from, 868 (unsigned long long) size); 869 goto out; 870 } 871 iov_iter_init(&f, ITER_SOURCE, vq->iotlb_iov, ret, size); 872 ret = copy_from_iter(to, size, &f); 873 if (ret == size) 874 ret = 0; 875 } 876 877 out: 878 return ret; 879 } 880 881 static void __user *__vhost_get_user_slow(struct vhost_virtqueue *vq, 882 void __user *addr, unsigned int size, 883 int type) 884 { 885 int ret; 886 887 ret = translate_desc(vq, (u64)(uintptr_t)addr, size, vq->iotlb_iov, 888 ARRAY_SIZE(vq->iotlb_iov), 889 VHOST_ACCESS_RO); 890 if (ret < 0) { 891 vq_err(vq, "IOTLB translation failure: uaddr " 892 "%p size 0x%llx\n", addr, 893 (unsigned long long) size); 894 return NULL; 895 } 896 897 if (ret != 1 || vq->iotlb_iov[0].iov_len != size) { 898 vq_err(vq, "Non atomic userspace memory access: uaddr " 899 "%p size 0x%llx\n", addr, 900 (unsigned long long) size); 901 return NULL; 902 } 903 904 return vq->iotlb_iov[0].iov_base; 905 } 906 907 /* This function should be called after iotlb 908 * prefetch, which means we're sure that vq 909 * could be access through iotlb. So -EAGAIN should 910 * not happen in this case. 911 */ 912 static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq, 913 void __user *addr, unsigned int size, 914 int type) 915 { 916 void __user *uaddr = vhost_vq_meta_fetch(vq, 917 (u64)(uintptr_t)addr, size, type); 918 if (uaddr) 919 return uaddr; 920 921 return __vhost_get_user_slow(vq, addr, size, type); 922 } 923 924 #define vhost_put_user(vq, x, ptr) \ 925 ({ \ 926 int ret; \ 927 if (!vq->iotlb) { \ 928 ret = __put_user(x, ptr); \ 929 } else { \ 930 __typeof__(ptr) to = \ 931 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \ 932 sizeof(*ptr), VHOST_ADDR_USED); \ 933 if (to != NULL) \ 934 ret = __put_user(x, to); \ 935 else \ 936 ret = -EFAULT; \ 937 } \ 938 ret; \ 939 }) 940 941 static inline int vhost_put_avail_event(struct vhost_virtqueue *vq) 942 { 943 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx), 944 vhost_avail_event(vq)); 945 } 946 947 static inline int vhost_put_used(struct vhost_virtqueue *vq, 948 struct vring_used_elem *head, int idx, 949 int count) 950 { 951 return vhost_copy_to_user(vq, vq->used->ring + idx, head, 952 count * sizeof(*head)); 953 } 954 955 static inline int vhost_put_used_flags(struct vhost_virtqueue *vq) 956 957 { 958 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags), 959 &vq->used->flags); 960 } 961 962 static inline int vhost_put_used_idx(struct vhost_virtqueue *vq) 963 964 { 965 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx), 966 &vq->used->idx); 967 } 968 969 #define vhost_get_user(vq, x, ptr, type) \ 970 ({ \ 971 int ret; \ 972 if (!vq->iotlb) { \ 973 ret = __get_user(x, ptr); \ 974 } else { \ 975 __typeof__(ptr) from = \ 976 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \ 977 sizeof(*ptr), \ 978 type); \ 979 if (from != NULL) \ 980 ret = __get_user(x, from); \ 981 else \ 982 ret = -EFAULT; \ 983 } \ 984 ret; \ 985 }) 986 987 #define vhost_get_avail(vq, x, ptr) \ 988 vhost_get_user(vq, x, ptr, VHOST_ADDR_AVAIL) 989 990 #define vhost_get_used(vq, x, ptr) \ 991 vhost_get_user(vq, x, ptr, VHOST_ADDR_USED) 992 993 static void vhost_dev_lock_vqs(struct vhost_dev *d) 994 { 995 int i = 0; 996 for (i = 0; i < d->nvqs; ++i) 997 mutex_lock_nested(&d->vqs[i]->mutex, i); 998 } 999 1000 static void vhost_dev_unlock_vqs(struct vhost_dev *d) 1001 { 1002 int i = 0; 1003 for (i = 0; i < d->nvqs; ++i) 1004 mutex_unlock(&d->vqs[i]->mutex); 1005 } 1006 1007 static inline int vhost_get_avail_idx(struct vhost_virtqueue *vq, 1008 __virtio16 *idx) 1009 { 1010 return vhost_get_avail(vq, *idx, &vq->avail->idx); 1011 } 1012 1013 static inline int vhost_get_avail_head(struct vhost_virtqueue *vq, 1014 __virtio16 *head, int idx) 1015 { 1016 return vhost_get_avail(vq, *head, 1017 &vq->avail->ring[idx & (vq->num - 1)]); 1018 } 1019 1020 static inline int vhost_get_avail_flags(struct vhost_virtqueue *vq, 1021 __virtio16 *flags) 1022 { 1023 return vhost_get_avail(vq, *flags, &vq->avail->flags); 1024 } 1025 1026 static inline int vhost_get_used_event(struct vhost_virtqueue *vq, 1027 __virtio16 *event) 1028 { 1029 return vhost_get_avail(vq, *event, vhost_used_event(vq)); 1030 } 1031 1032 static inline int vhost_get_used_idx(struct vhost_virtqueue *vq, 1033 __virtio16 *idx) 1034 { 1035 return vhost_get_used(vq, *idx, &vq->used->idx); 1036 } 1037 1038 static inline int vhost_get_desc(struct vhost_virtqueue *vq, 1039 struct vring_desc *desc, int idx) 1040 { 1041 return vhost_copy_from_user(vq, desc, vq->desc + idx, sizeof(*desc)); 1042 } 1043 1044 static void vhost_iotlb_notify_vq(struct vhost_dev *d, 1045 struct vhost_iotlb_msg *msg) 1046 { 1047 struct vhost_msg_node *node, *n; 1048 1049 spin_lock(&d->iotlb_lock); 1050 1051 list_for_each_entry_safe(node, n, &d->pending_list, node) { 1052 struct vhost_iotlb_msg *vq_msg = &node->msg.iotlb; 1053 if (msg->iova <= vq_msg->iova && 1054 msg->iova + msg->size - 1 >= vq_msg->iova && 1055 vq_msg->type == VHOST_IOTLB_MISS) { 1056 vhost_poll_queue(&node->vq->poll); 1057 list_del(&node->node); 1058 kfree(node); 1059 } 1060 } 1061 1062 spin_unlock(&d->iotlb_lock); 1063 } 1064 1065 static bool umem_access_ok(u64 uaddr, u64 size, int access) 1066 { 1067 unsigned long a = uaddr; 1068 1069 /* Make sure 64 bit math will not overflow. */ 1070 if (vhost_overflow(uaddr, size)) 1071 return false; 1072 1073 if ((access & VHOST_ACCESS_RO) && 1074 !access_ok((void __user *)a, size)) 1075 return false; 1076 if ((access & VHOST_ACCESS_WO) && 1077 !access_ok((void __user *)a, size)) 1078 return false; 1079 return true; 1080 } 1081 1082 static int vhost_process_iotlb_msg(struct vhost_dev *dev, u32 asid, 1083 struct vhost_iotlb_msg *msg) 1084 { 1085 int ret = 0; 1086 1087 if (asid != 0) 1088 return -EINVAL; 1089 1090 mutex_lock(&dev->mutex); 1091 vhost_dev_lock_vqs(dev); 1092 switch (msg->type) { 1093 case VHOST_IOTLB_UPDATE: 1094 if (!dev->iotlb) { 1095 ret = -EFAULT; 1096 break; 1097 } 1098 if (!umem_access_ok(msg->uaddr, msg->size, msg->perm)) { 1099 ret = -EFAULT; 1100 break; 1101 } 1102 vhost_vq_meta_reset(dev); 1103 if (vhost_iotlb_add_range(dev->iotlb, msg->iova, 1104 msg->iova + msg->size - 1, 1105 msg->uaddr, msg->perm)) { 1106 ret = -ENOMEM; 1107 break; 1108 } 1109 vhost_iotlb_notify_vq(dev, msg); 1110 break; 1111 case VHOST_IOTLB_INVALIDATE: 1112 if (!dev->iotlb) { 1113 ret = -EFAULT; 1114 break; 1115 } 1116 vhost_vq_meta_reset(dev); 1117 vhost_iotlb_del_range(dev->iotlb, msg->iova, 1118 msg->iova + msg->size - 1); 1119 break; 1120 default: 1121 ret = -EINVAL; 1122 break; 1123 } 1124 1125 vhost_dev_unlock_vqs(dev); 1126 mutex_unlock(&dev->mutex); 1127 1128 return ret; 1129 } 1130 ssize_t vhost_chr_write_iter(struct vhost_dev *dev, 1131 struct iov_iter *from) 1132 { 1133 struct vhost_iotlb_msg msg; 1134 size_t offset; 1135 int type, ret; 1136 u32 asid = 0; 1137 1138 ret = copy_from_iter(&type, sizeof(type), from); 1139 if (ret != sizeof(type)) { 1140 ret = -EINVAL; 1141 goto done; 1142 } 1143 1144 switch (type) { 1145 case VHOST_IOTLB_MSG: 1146 /* There maybe a hole after type for V1 message type, 1147 * so skip it here. 1148 */ 1149 offset = offsetof(struct vhost_msg, iotlb) - sizeof(int); 1150 break; 1151 case VHOST_IOTLB_MSG_V2: 1152 if (vhost_backend_has_feature(dev->vqs[0], 1153 VHOST_BACKEND_F_IOTLB_ASID)) { 1154 ret = copy_from_iter(&asid, sizeof(asid), from); 1155 if (ret != sizeof(asid)) { 1156 ret = -EINVAL; 1157 goto done; 1158 } 1159 offset = 0; 1160 } else 1161 offset = sizeof(__u32); 1162 break; 1163 default: 1164 ret = -EINVAL; 1165 goto done; 1166 } 1167 1168 iov_iter_advance(from, offset); 1169 ret = copy_from_iter(&msg, sizeof(msg), from); 1170 if (ret != sizeof(msg)) { 1171 ret = -EINVAL; 1172 goto done; 1173 } 1174 1175 if ((msg.type == VHOST_IOTLB_UPDATE || 1176 msg.type == VHOST_IOTLB_INVALIDATE) && 1177 msg.size == 0) { 1178 ret = -EINVAL; 1179 goto done; 1180 } 1181 1182 if (dev->msg_handler) 1183 ret = dev->msg_handler(dev, asid, &msg); 1184 else 1185 ret = vhost_process_iotlb_msg(dev, asid, &msg); 1186 if (ret) { 1187 ret = -EFAULT; 1188 goto done; 1189 } 1190 1191 ret = (type == VHOST_IOTLB_MSG) ? sizeof(struct vhost_msg) : 1192 sizeof(struct vhost_msg_v2); 1193 done: 1194 return ret; 1195 } 1196 EXPORT_SYMBOL(vhost_chr_write_iter); 1197 1198 __poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev, 1199 poll_table *wait) 1200 { 1201 __poll_t mask = 0; 1202 1203 poll_wait(file, &dev->wait, wait); 1204 1205 if (!list_empty(&dev->read_list)) 1206 mask |= EPOLLIN | EPOLLRDNORM; 1207 1208 return mask; 1209 } 1210 EXPORT_SYMBOL(vhost_chr_poll); 1211 1212 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to, 1213 int noblock) 1214 { 1215 DEFINE_WAIT(wait); 1216 struct vhost_msg_node *node; 1217 ssize_t ret = 0; 1218 unsigned size = sizeof(struct vhost_msg); 1219 1220 if (iov_iter_count(to) < size) 1221 return 0; 1222 1223 while (1) { 1224 if (!noblock) 1225 prepare_to_wait(&dev->wait, &wait, 1226 TASK_INTERRUPTIBLE); 1227 1228 node = vhost_dequeue_msg(dev, &dev->read_list); 1229 if (node) 1230 break; 1231 if (noblock) { 1232 ret = -EAGAIN; 1233 break; 1234 } 1235 if (signal_pending(current)) { 1236 ret = -ERESTARTSYS; 1237 break; 1238 } 1239 if (!dev->iotlb) { 1240 ret = -EBADFD; 1241 break; 1242 } 1243 1244 schedule(); 1245 } 1246 1247 if (!noblock) 1248 finish_wait(&dev->wait, &wait); 1249 1250 if (node) { 1251 struct vhost_iotlb_msg *msg; 1252 void *start = &node->msg; 1253 1254 switch (node->msg.type) { 1255 case VHOST_IOTLB_MSG: 1256 size = sizeof(node->msg); 1257 msg = &node->msg.iotlb; 1258 break; 1259 case VHOST_IOTLB_MSG_V2: 1260 size = sizeof(node->msg_v2); 1261 msg = &node->msg_v2.iotlb; 1262 break; 1263 default: 1264 BUG(); 1265 break; 1266 } 1267 1268 ret = copy_to_iter(start, size, to); 1269 if (ret != size || msg->type != VHOST_IOTLB_MISS) { 1270 kfree(node); 1271 return ret; 1272 } 1273 vhost_enqueue_msg(dev, &dev->pending_list, node); 1274 } 1275 1276 return ret; 1277 } 1278 EXPORT_SYMBOL_GPL(vhost_chr_read_iter); 1279 1280 static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access) 1281 { 1282 struct vhost_dev *dev = vq->dev; 1283 struct vhost_msg_node *node; 1284 struct vhost_iotlb_msg *msg; 1285 bool v2 = vhost_backend_has_feature(vq, VHOST_BACKEND_F_IOTLB_MSG_V2); 1286 1287 node = vhost_new_msg(vq, v2 ? VHOST_IOTLB_MSG_V2 : VHOST_IOTLB_MSG); 1288 if (!node) 1289 return -ENOMEM; 1290 1291 if (v2) { 1292 node->msg_v2.type = VHOST_IOTLB_MSG_V2; 1293 msg = &node->msg_v2.iotlb; 1294 } else { 1295 msg = &node->msg.iotlb; 1296 } 1297 1298 msg->type = VHOST_IOTLB_MISS; 1299 msg->iova = iova; 1300 msg->perm = access; 1301 1302 vhost_enqueue_msg(dev, &dev->read_list, node); 1303 1304 return 0; 1305 } 1306 1307 static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num, 1308 vring_desc_t __user *desc, 1309 vring_avail_t __user *avail, 1310 vring_used_t __user *used) 1311 1312 { 1313 /* If an IOTLB device is present, the vring addresses are 1314 * GIOVAs. Access validation occurs at prefetch time. */ 1315 if (vq->iotlb) 1316 return true; 1317 1318 return access_ok(desc, vhost_get_desc_size(vq, num)) && 1319 access_ok(avail, vhost_get_avail_size(vq, num)) && 1320 access_ok(used, vhost_get_used_size(vq, num)); 1321 } 1322 1323 static void vhost_vq_meta_update(struct vhost_virtqueue *vq, 1324 const struct vhost_iotlb_map *map, 1325 int type) 1326 { 1327 int access = (type == VHOST_ADDR_USED) ? 1328 VHOST_ACCESS_WO : VHOST_ACCESS_RO; 1329 1330 if (likely(map->perm & access)) 1331 vq->meta_iotlb[type] = map; 1332 } 1333 1334 static bool iotlb_access_ok(struct vhost_virtqueue *vq, 1335 int access, u64 addr, u64 len, int type) 1336 { 1337 const struct vhost_iotlb_map *map; 1338 struct vhost_iotlb *umem = vq->iotlb; 1339 u64 s = 0, size, orig_addr = addr, last = addr + len - 1; 1340 1341 if (vhost_vq_meta_fetch(vq, addr, len, type)) 1342 return true; 1343 1344 while (len > s) { 1345 map = vhost_iotlb_itree_first(umem, addr, last); 1346 if (map == NULL || map->start > addr) { 1347 vhost_iotlb_miss(vq, addr, access); 1348 return false; 1349 } else if (!(map->perm & access)) { 1350 /* Report the possible access violation by 1351 * request another translation from userspace. 1352 */ 1353 return false; 1354 } 1355 1356 size = map->size - addr + map->start; 1357 1358 if (orig_addr == addr && size >= len) 1359 vhost_vq_meta_update(vq, map, type); 1360 1361 s += size; 1362 addr += size; 1363 } 1364 1365 return true; 1366 } 1367 1368 int vq_meta_prefetch(struct vhost_virtqueue *vq) 1369 { 1370 unsigned int num = vq->num; 1371 1372 if (!vq->iotlb) 1373 return 1; 1374 1375 return iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->desc, 1376 vhost_get_desc_size(vq, num), VHOST_ADDR_DESC) && 1377 iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->avail, 1378 vhost_get_avail_size(vq, num), 1379 VHOST_ADDR_AVAIL) && 1380 iotlb_access_ok(vq, VHOST_MAP_WO, (u64)(uintptr_t)vq->used, 1381 vhost_get_used_size(vq, num), VHOST_ADDR_USED); 1382 } 1383 EXPORT_SYMBOL_GPL(vq_meta_prefetch); 1384 1385 /* Can we log writes? */ 1386 /* Caller should have device mutex but not vq mutex */ 1387 bool vhost_log_access_ok(struct vhost_dev *dev) 1388 { 1389 return memory_access_ok(dev, dev->umem, 1); 1390 } 1391 EXPORT_SYMBOL_GPL(vhost_log_access_ok); 1392 1393 static bool vq_log_used_access_ok(struct vhost_virtqueue *vq, 1394 void __user *log_base, 1395 bool log_used, 1396 u64 log_addr) 1397 { 1398 /* If an IOTLB device is present, log_addr is a GIOVA that 1399 * will never be logged by log_used(). */ 1400 if (vq->iotlb) 1401 return true; 1402 1403 return !log_used || log_access_ok(log_base, log_addr, 1404 vhost_get_used_size(vq, vq->num)); 1405 } 1406 1407 /* Verify access for write logging. */ 1408 /* Caller should have vq mutex and device mutex */ 1409 static bool vq_log_access_ok(struct vhost_virtqueue *vq, 1410 void __user *log_base) 1411 { 1412 return vq_memory_access_ok(log_base, vq->umem, 1413 vhost_has_feature(vq, VHOST_F_LOG_ALL)) && 1414 vq_log_used_access_ok(vq, log_base, vq->log_used, vq->log_addr); 1415 } 1416 1417 /* Can we start vq? */ 1418 /* Caller should have vq mutex and device mutex */ 1419 bool vhost_vq_access_ok(struct vhost_virtqueue *vq) 1420 { 1421 if (!vq_log_access_ok(vq, vq->log_base)) 1422 return false; 1423 1424 return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used); 1425 } 1426 EXPORT_SYMBOL_GPL(vhost_vq_access_ok); 1427 1428 static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) 1429 { 1430 struct vhost_memory mem, *newmem; 1431 struct vhost_memory_region *region; 1432 struct vhost_iotlb *newumem, *oldumem; 1433 unsigned long size = offsetof(struct vhost_memory, regions); 1434 int i; 1435 1436 if (copy_from_user(&mem, m, size)) 1437 return -EFAULT; 1438 if (mem.padding) 1439 return -EOPNOTSUPP; 1440 if (mem.nregions > max_mem_regions) 1441 return -E2BIG; 1442 newmem = kvzalloc(struct_size(newmem, regions, mem.nregions), 1443 GFP_KERNEL); 1444 if (!newmem) 1445 return -ENOMEM; 1446 1447 memcpy(newmem, &mem, size); 1448 if (copy_from_user(newmem->regions, m->regions, 1449 flex_array_size(newmem, regions, mem.nregions))) { 1450 kvfree(newmem); 1451 return -EFAULT; 1452 } 1453 1454 newumem = iotlb_alloc(); 1455 if (!newumem) { 1456 kvfree(newmem); 1457 return -ENOMEM; 1458 } 1459 1460 for (region = newmem->regions; 1461 region < newmem->regions + mem.nregions; 1462 region++) { 1463 if (vhost_iotlb_add_range(newumem, 1464 region->guest_phys_addr, 1465 region->guest_phys_addr + 1466 region->memory_size - 1, 1467 region->userspace_addr, 1468 VHOST_MAP_RW)) 1469 goto err; 1470 } 1471 1472 if (!memory_access_ok(d, newumem, 0)) 1473 goto err; 1474 1475 oldumem = d->umem; 1476 d->umem = newumem; 1477 1478 /* All memory accesses are done under some VQ mutex. */ 1479 for (i = 0; i < d->nvqs; ++i) { 1480 mutex_lock(&d->vqs[i]->mutex); 1481 d->vqs[i]->umem = newumem; 1482 mutex_unlock(&d->vqs[i]->mutex); 1483 } 1484 1485 kvfree(newmem); 1486 vhost_iotlb_free(oldumem); 1487 return 0; 1488 1489 err: 1490 vhost_iotlb_free(newumem); 1491 kvfree(newmem); 1492 return -EFAULT; 1493 } 1494 1495 static long vhost_vring_set_num(struct vhost_dev *d, 1496 struct vhost_virtqueue *vq, 1497 void __user *argp) 1498 { 1499 struct vhost_vring_state s; 1500 1501 /* Resizing ring with an active backend? 1502 * You don't want to do that. */ 1503 if (vq->private_data) 1504 return -EBUSY; 1505 1506 if (copy_from_user(&s, argp, sizeof s)) 1507 return -EFAULT; 1508 1509 if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) 1510 return -EINVAL; 1511 vq->num = s.num; 1512 1513 return 0; 1514 } 1515 1516 static long vhost_vring_set_addr(struct vhost_dev *d, 1517 struct vhost_virtqueue *vq, 1518 void __user *argp) 1519 { 1520 struct vhost_vring_addr a; 1521 1522 if (copy_from_user(&a, argp, sizeof a)) 1523 return -EFAULT; 1524 if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) 1525 return -EOPNOTSUPP; 1526 1527 /* For 32bit, verify that the top 32bits of the user 1528 data are set to zero. */ 1529 if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr || 1530 (u64)(unsigned long)a.used_user_addr != a.used_user_addr || 1531 (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) 1532 return -EFAULT; 1533 1534 /* Make sure it's safe to cast pointers to vring types. */ 1535 BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE); 1536 BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE); 1537 if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) || 1538 (a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) || 1539 (a.log_guest_addr & (VRING_USED_ALIGN_SIZE - 1))) 1540 return -EINVAL; 1541 1542 /* We only verify access here if backend is configured. 1543 * If it is not, we don't as size might not have been setup. 1544 * We will verify when backend is configured. */ 1545 if (vq->private_data) { 1546 if (!vq_access_ok(vq, vq->num, 1547 (void __user *)(unsigned long)a.desc_user_addr, 1548 (void __user *)(unsigned long)a.avail_user_addr, 1549 (void __user *)(unsigned long)a.used_user_addr)) 1550 return -EINVAL; 1551 1552 /* Also validate log access for used ring if enabled. */ 1553 if (!vq_log_used_access_ok(vq, vq->log_base, 1554 a.flags & (0x1 << VHOST_VRING_F_LOG), 1555 a.log_guest_addr)) 1556 return -EINVAL; 1557 } 1558 1559 vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG)); 1560 vq->desc = (void __user *)(unsigned long)a.desc_user_addr; 1561 vq->avail = (void __user *)(unsigned long)a.avail_user_addr; 1562 vq->log_addr = a.log_guest_addr; 1563 vq->used = (void __user *)(unsigned long)a.used_user_addr; 1564 1565 return 0; 1566 } 1567 1568 static long vhost_vring_set_num_addr(struct vhost_dev *d, 1569 struct vhost_virtqueue *vq, 1570 unsigned int ioctl, 1571 void __user *argp) 1572 { 1573 long r; 1574 1575 mutex_lock(&vq->mutex); 1576 1577 switch (ioctl) { 1578 case VHOST_SET_VRING_NUM: 1579 r = vhost_vring_set_num(d, vq, argp); 1580 break; 1581 case VHOST_SET_VRING_ADDR: 1582 r = vhost_vring_set_addr(d, vq, argp); 1583 break; 1584 default: 1585 BUG(); 1586 } 1587 1588 mutex_unlock(&vq->mutex); 1589 1590 return r; 1591 } 1592 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp) 1593 { 1594 struct file *eventfp, *filep = NULL; 1595 bool pollstart = false, pollstop = false; 1596 struct eventfd_ctx *ctx = NULL; 1597 u32 __user *idxp = argp; 1598 struct vhost_virtqueue *vq; 1599 struct vhost_vring_state s; 1600 struct vhost_vring_file f; 1601 u32 idx; 1602 long r; 1603 1604 r = get_user(idx, idxp); 1605 if (r < 0) 1606 return r; 1607 if (idx >= d->nvqs) 1608 return -ENOBUFS; 1609 1610 idx = array_index_nospec(idx, d->nvqs); 1611 vq = d->vqs[idx]; 1612 1613 if (ioctl == VHOST_SET_VRING_NUM || 1614 ioctl == VHOST_SET_VRING_ADDR) { 1615 return vhost_vring_set_num_addr(d, vq, ioctl, argp); 1616 } 1617 1618 mutex_lock(&vq->mutex); 1619 1620 switch (ioctl) { 1621 case VHOST_SET_VRING_BASE: 1622 /* Moving base with an active backend? 1623 * You don't want to do that. */ 1624 if (vq->private_data) { 1625 r = -EBUSY; 1626 break; 1627 } 1628 if (copy_from_user(&s, argp, sizeof s)) { 1629 r = -EFAULT; 1630 break; 1631 } 1632 if (s.num > 0xffff) { 1633 r = -EINVAL; 1634 break; 1635 } 1636 vq->last_avail_idx = s.num; 1637 /* Forget the cached index value. */ 1638 vq->avail_idx = vq->last_avail_idx; 1639 break; 1640 case VHOST_GET_VRING_BASE: 1641 s.index = idx; 1642 s.num = vq->last_avail_idx; 1643 if (copy_to_user(argp, &s, sizeof s)) 1644 r = -EFAULT; 1645 break; 1646 case VHOST_SET_VRING_KICK: 1647 if (copy_from_user(&f, argp, sizeof f)) { 1648 r = -EFAULT; 1649 break; 1650 } 1651 eventfp = f.fd == VHOST_FILE_UNBIND ? NULL : eventfd_fget(f.fd); 1652 if (IS_ERR(eventfp)) { 1653 r = PTR_ERR(eventfp); 1654 break; 1655 } 1656 if (eventfp != vq->kick) { 1657 pollstop = (filep = vq->kick) != NULL; 1658 pollstart = (vq->kick = eventfp) != NULL; 1659 } else 1660 filep = eventfp; 1661 break; 1662 case VHOST_SET_VRING_CALL: 1663 if (copy_from_user(&f, argp, sizeof f)) { 1664 r = -EFAULT; 1665 break; 1666 } 1667 ctx = f.fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(f.fd); 1668 if (IS_ERR(ctx)) { 1669 r = PTR_ERR(ctx); 1670 break; 1671 } 1672 1673 swap(ctx, vq->call_ctx.ctx); 1674 break; 1675 case VHOST_SET_VRING_ERR: 1676 if (copy_from_user(&f, argp, sizeof f)) { 1677 r = -EFAULT; 1678 break; 1679 } 1680 ctx = f.fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(f.fd); 1681 if (IS_ERR(ctx)) { 1682 r = PTR_ERR(ctx); 1683 break; 1684 } 1685 swap(ctx, vq->error_ctx); 1686 break; 1687 case VHOST_SET_VRING_ENDIAN: 1688 r = vhost_set_vring_endian(vq, argp); 1689 break; 1690 case VHOST_GET_VRING_ENDIAN: 1691 r = vhost_get_vring_endian(vq, idx, argp); 1692 break; 1693 case VHOST_SET_VRING_BUSYLOOP_TIMEOUT: 1694 if (copy_from_user(&s, argp, sizeof(s))) { 1695 r = -EFAULT; 1696 break; 1697 } 1698 vq->busyloop_timeout = s.num; 1699 break; 1700 case VHOST_GET_VRING_BUSYLOOP_TIMEOUT: 1701 s.index = idx; 1702 s.num = vq->busyloop_timeout; 1703 if (copy_to_user(argp, &s, sizeof(s))) 1704 r = -EFAULT; 1705 break; 1706 default: 1707 r = -ENOIOCTLCMD; 1708 } 1709 1710 if (pollstop && vq->handle_kick) 1711 vhost_poll_stop(&vq->poll); 1712 1713 if (!IS_ERR_OR_NULL(ctx)) 1714 eventfd_ctx_put(ctx); 1715 if (filep) 1716 fput(filep); 1717 1718 if (pollstart && vq->handle_kick) 1719 r = vhost_poll_start(&vq->poll, vq->kick); 1720 1721 mutex_unlock(&vq->mutex); 1722 1723 if (pollstop && vq->handle_kick) 1724 vhost_dev_flush(vq->poll.dev); 1725 return r; 1726 } 1727 EXPORT_SYMBOL_GPL(vhost_vring_ioctl); 1728 1729 int vhost_init_device_iotlb(struct vhost_dev *d) 1730 { 1731 struct vhost_iotlb *niotlb, *oiotlb; 1732 int i; 1733 1734 niotlb = iotlb_alloc(); 1735 if (!niotlb) 1736 return -ENOMEM; 1737 1738 oiotlb = d->iotlb; 1739 d->iotlb = niotlb; 1740 1741 for (i = 0; i < d->nvqs; ++i) { 1742 struct vhost_virtqueue *vq = d->vqs[i]; 1743 1744 mutex_lock(&vq->mutex); 1745 vq->iotlb = niotlb; 1746 __vhost_vq_meta_reset(vq); 1747 mutex_unlock(&vq->mutex); 1748 } 1749 1750 vhost_iotlb_free(oiotlb); 1751 1752 return 0; 1753 } 1754 EXPORT_SYMBOL_GPL(vhost_init_device_iotlb); 1755 1756 /* Caller must have device mutex */ 1757 long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp) 1758 { 1759 struct eventfd_ctx *ctx; 1760 u64 p; 1761 long r; 1762 int i, fd; 1763 1764 /* If you are not the owner, you can become one */ 1765 if (ioctl == VHOST_SET_OWNER) { 1766 r = vhost_dev_set_owner(d); 1767 goto done; 1768 } 1769 1770 /* You must be the owner to do anything else */ 1771 r = vhost_dev_check_owner(d); 1772 if (r) 1773 goto done; 1774 1775 switch (ioctl) { 1776 case VHOST_SET_MEM_TABLE: 1777 r = vhost_set_memory(d, argp); 1778 break; 1779 case VHOST_SET_LOG_BASE: 1780 if (copy_from_user(&p, argp, sizeof p)) { 1781 r = -EFAULT; 1782 break; 1783 } 1784 if ((u64)(unsigned long)p != p) { 1785 r = -EFAULT; 1786 break; 1787 } 1788 for (i = 0; i < d->nvqs; ++i) { 1789 struct vhost_virtqueue *vq; 1790 void __user *base = (void __user *)(unsigned long)p; 1791 vq = d->vqs[i]; 1792 mutex_lock(&vq->mutex); 1793 /* If ring is inactive, will check when it's enabled. */ 1794 if (vq->private_data && !vq_log_access_ok(vq, base)) 1795 r = -EFAULT; 1796 else 1797 vq->log_base = base; 1798 mutex_unlock(&vq->mutex); 1799 } 1800 break; 1801 case VHOST_SET_LOG_FD: 1802 r = get_user(fd, (int __user *)argp); 1803 if (r < 0) 1804 break; 1805 ctx = fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(fd); 1806 if (IS_ERR(ctx)) { 1807 r = PTR_ERR(ctx); 1808 break; 1809 } 1810 swap(ctx, d->log_ctx); 1811 for (i = 0; i < d->nvqs; ++i) { 1812 mutex_lock(&d->vqs[i]->mutex); 1813 d->vqs[i]->log_ctx = d->log_ctx; 1814 mutex_unlock(&d->vqs[i]->mutex); 1815 } 1816 if (ctx) 1817 eventfd_ctx_put(ctx); 1818 break; 1819 default: 1820 r = -ENOIOCTLCMD; 1821 break; 1822 } 1823 done: 1824 return r; 1825 } 1826 EXPORT_SYMBOL_GPL(vhost_dev_ioctl); 1827 1828 /* TODO: This is really inefficient. We need something like get_user() 1829 * (instruction directly accesses the data, with an exception table entry 1830 * returning -EFAULT). See Documentation/arch/x86/exception-tables.rst. 1831 */ 1832 static int set_bit_to_user(int nr, void __user *addr) 1833 { 1834 unsigned long log = (unsigned long)addr; 1835 struct page *page; 1836 void *base; 1837 int bit = nr + (log % PAGE_SIZE) * 8; 1838 int r; 1839 1840 r = pin_user_pages_fast(log, 1, FOLL_WRITE, &page); 1841 if (r < 0) 1842 return r; 1843 BUG_ON(r != 1); 1844 base = kmap_atomic(page); 1845 set_bit(bit, base); 1846 kunmap_atomic(base); 1847 unpin_user_pages_dirty_lock(&page, 1, true); 1848 return 0; 1849 } 1850 1851 static int log_write(void __user *log_base, 1852 u64 write_address, u64 write_length) 1853 { 1854 u64 write_page = write_address / VHOST_PAGE_SIZE; 1855 int r; 1856 1857 if (!write_length) 1858 return 0; 1859 write_length += write_address % VHOST_PAGE_SIZE; 1860 for (;;) { 1861 u64 base = (u64)(unsigned long)log_base; 1862 u64 log = base + write_page / 8; 1863 int bit = write_page % 8; 1864 if ((u64)(unsigned long)log != log) 1865 return -EFAULT; 1866 r = set_bit_to_user(bit, (void __user *)(unsigned long)log); 1867 if (r < 0) 1868 return r; 1869 if (write_length <= VHOST_PAGE_SIZE) 1870 break; 1871 write_length -= VHOST_PAGE_SIZE; 1872 write_page += 1; 1873 } 1874 return r; 1875 } 1876 1877 static int log_write_hva(struct vhost_virtqueue *vq, u64 hva, u64 len) 1878 { 1879 struct vhost_iotlb *umem = vq->umem; 1880 struct vhost_iotlb_map *u; 1881 u64 start, end, l, min; 1882 int r; 1883 bool hit = false; 1884 1885 while (len) { 1886 min = len; 1887 /* More than one GPAs can be mapped into a single HVA. So 1888 * iterate all possible umems here to be safe. 1889 */ 1890 list_for_each_entry(u, &umem->list, link) { 1891 if (u->addr > hva - 1 + len || 1892 u->addr - 1 + u->size < hva) 1893 continue; 1894 start = max(u->addr, hva); 1895 end = min(u->addr - 1 + u->size, hva - 1 + len); 1896 l = end - start + 1; 1897 r = log_write(vq->log_base, 1898 u->start + start - u->addr, 1899 l); 1900 if (r < 0) 1901 return r; 1902 hit = true; 1903 min = min(l, min); 1904 } 1905 1906 if (!hit) 1907 return -EFAULT; 1908 1909 len -= min; 1910 hva += min; 1911 } 1912 1913 return 0; 1914 } 1915 1916 static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len) 1917 { 1918 struct iovec *iov = vq->log_iov; 1919 int i, ret; 1920 1921 if (!vq->iotlb) 1922 return log_write(vq->log_base, vq->log_addr + used_offset, len); 1923 1924 ret = translate_desc(vq, (uintptr_t)vq->used + used_offset, 1925 len, iov, 64, VHOST_ACCESS_WO); 1926 if (ret < 0) 1927 return ret; 1928 1929 for (i = 0; i < ret; i++) { 1930 ret = log_write_hva(vq, (uintptr_t)iov[i].iov_base, 1931 iov[i].iov_len); 1932 if (ret) 1933 return ret; 1934 } 1935 1936 return 0; 1937 } 1938 1939 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, 1940 unsigned int log_num, u64 len, struct iovec *iov, int count) 1941 { 1942 int i, r; 1943 1944 /* Make sure data written is seen before log. */ 1945 smp_wmb(); 1946 1947 if (vq->iotlb) { 1948 for (i = 0; i < count; i++) { 1949 r = log_write_hva(vq, (uintptr_t)iov[i].iov_base, 1950 iov[i].iov_len); 1951 if (r < 0) 1952 return r; 1953 } 1954 return 0; 1955 } 1956 1957 for (i = 0; i < log_num; ++i) { 1958 u64 l = min(log[i].len, len); 1959 r = log_write(vq->log_base, log[i].addr, l); 1960 if (r < 0) 1961 return r; 1962 len -= l; 1963 if (!len) { 1964 if (vq->log_ctx) 1965 eventfd_signal(vq->log_ctx, 1); 1966 return 0; 1967 } 1968 } 1969 /* Length written exceeds what we have stored. This is a bug. */ 1970 BUG(); 1971 return 0; 1972 } 1973 EXPORT_SYMBOL_GPL(vhost_log_write); 1974 1975 static int vhost_update_used_flags(struct vhost_virtqueue *vq) 1976 { 1977 void __user *used; 1978 if (vhost_put_used_flags(vq)) 1979 return -EFAULT; 1980 if (unlikely(vq->log_used)) { 1981 /* Make sure the flag is seen before log. */ 1982 smp_wmb(); 1983 /* Log used flag write. */ 1984 used = &vq->used->flags; 1985 log_used(vq, (used - (void __user *)vq->used), 1986 sizeof vq->used->flags); 1987 if (vq->log_ctx) 1988 eventfd_signal(vq->log_ctx, 1); 1989 } 1990 return 0; 1991 } 1992 1993 static int vhost_update_avail_event(struct vhost_virtqueue *vq) 1994 { 1995 if (vhost_put_avail_event(vq)) 1996 return -EFAULT; 1997 if (unlikely(vq->log_used)) { 1998 void __user *used; 1999 /* Make sure the event is seen before log. */ 2000 smp_wmb(); 2001 /* Log avail event write */ 2002 used = vhost_avail_event(vq); 2003 log_used(vq, (used - (void __user *)vq->used), 2004 sizeof *vhost_avail_event(vq)); 2005 if (vq->log_ctx) 2006 eventfd_signal(vq->log_ctx, 1); 2007 } 2008 return 0; 2009 } 2010 2011 int vhost_vq_init_access(struct vhost_virtqueue *vq) 2012 { 2013 __virtio16 last_used_idx; 2014 int r; 2015 bool is_le = vq->is_le; 2016 2017 if (!vq->private_data) 2018 return 0; 2019 2020 vhost_init_is_le(vq); 2021 2022 r = vhost_update_used_flags(vq); 2023 if (r) 2024 goto err; 2025 vq->signalled_used_valid = false; 2026 if (!vq->iotlb && 2027 !access_ok(&vq->used->idx, sizeof vq->used->idx)) { 2028 r = -EFAULT; 2029 goto err; 2030 } 2031 r = vhost_get_used_idx(vq, &last_used_idx); 2032 if (r) { 2033 vq_err(vq, "Can't access used idx at %p\n", 2034 &vq->used->idx); 2035 goto err; 2036 } 2037 vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx); 2038 return 0; 2039 2040 err: 2041 vq->is_le = is_le; 2042 return r; 2043 } 2044 EXPORT_SYMBOL_GPL(vhost_vq_init_access); 2045 2046 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len, 2047 struct iovec iov[], int iov_size, int access) 2048 { 2049 const struct vhost_iotlb_map *map; 2050 struct vhost_dev *dev = vq->dev; 2051 struct vhost_iotlb *umem = dev->iotlb ? dev->iotlb : dev->umem; 2052 struct iovec *_iov; 2053 u64 s = 0, last = addr + len - 1; 2054 int ret = 0; 2055 2056 while ((u64)len > s) { 2057 u64 size; 2058 if (unlikely(ret >= iov_size)) { 2059 ret = -ENOBUFS; 2060 break; 2061 } 2062 2063 map = vhost_iotlb_itree_first(umem, addr, last); 2064 if (map == NULL || map->start > addr) { 2065 if (umem != dev->iotlb) { 2066 ret = -EFAULT; 2067 break; 2068 } 2069 ret = -EAGAIN; 2070 break; 2071 } else if (!(map->perm & access)) { 2072 ret = -EPERM; 2073 break; 2074 } 2075 2076 _iov = iov + ret; 2077 size = map->size - addr + map->start; 2078 _iov->iov_len = min((u64)len - s, size); 2079 _iov->iov_base = (void __user *)(unsigned long) 2080 (map->addr + addr - map->start); 2081 s += size; 2082 addr += size; 2083 ++ret; 2084 } 2085 2086 if (ret == -EAGAIN) 2087 vhost_iotlb_miss(vq, addr, access); 2088 return ret; 2089 } 2090 2091 /* Each buffer in the virtqueues is actually a chain of descriptors. This 2092 * function returns the next descriptor in the chain, 2093 * or -1U if we're at the end. */ 2094 static unsigned next_desc(struct vhost_virtqueue *vq, struct vring_desc *desc) 2095 { 2096 unsigned int next; 2097 2098 /* If this descriptor says it doesn't chain, we're done. */ 2099 if (!(desc->flags & cpu_to_vhost16(vq, VRING_DESC_F_NEXT))) 2100 return -1U; 2101 2102 /* Check they're not leading us off end of descriptors. */ 2103 next = vhost16_to_cpu(vq, READ_ONCE(desc->next)); 2104 return next; 2105 } 2106 2107 static int get_indirect(struct vhost_virtqueue *vq, 2108 struct iovec iov[], unsigned int iov_size, 2109 unsigned int *out_num, unsigned int *in_num, 2110 struct vhost_log *log, unsigned int *log_num, 2111 struct vring_desc *indirect) 2112 { 2113 struct vring_desc desc; 2114 unsigned int i = 0, count, found = 0; 2115 u32 len = vhost32_to_cpu(vq, indirect->len); 2116 struct iov_iter from; 2117 int ret, access; 2118 2119 /* Sanity check */ 2120 if (unlikely(len % sizeof desc)) { 2121 vq_err(vq, "Invalid length in indirect descriptor: " 2122 "len 0x%llx not multiple of 0x%zx\n", 2123 (unsigned long long)len, 2124 sizeof desc); 2125 return -EINVAL; 2126 } 2127 2128 ret = translate_desc(vq, vhost64_to_cpu(vq, indirect->addr), len, vq->indirect, 2129 UIO_MAXIOV, VHOST_ACCESS_RO); 2130 if (unlikely(ret < 0)) { 2131 if (ret != -EAGAIN) 2132 vq_err(vq, "Translation failure %d in indirect.\n", ret); 2133 return ret; 2134 } 2135 iov_iter_init(&from, ITER_SOURCE, vq->indirect, ret, len); 2136 count = len / sizeof desc; 2137 /* Buffers are chained via a 16 bit next field, so 2138 * we can have at most 2^16 of these. */ 2139 if (unlikely(count > USHRT_MAX + 1)) { 2140 vq_err(vq, "Indirect buffer length too big: %d\n", 2141 indirect->len); 2142 return -E2BIG; 2143 } 2144 2145 do { 2146 unsigned iov_count = *in_num + *out_num; 2147 if (unlikely(++found > count)) { 2148 vq_err(vq, "Loop detected: last one at %u " 2149 "indirect size %u\n", 2150 i, count); 2151 return -EINVAL; 2152 } 2153 if (unlikely(!copy_from_iter_full(&desc, sizeof(desc), &from))) { 2154 vq_err(vq, "Failed indirect descriptor: idx %d, %zx\n", 2155 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc); 2156 return -EINVAL; 2157 } 2158 if (unlikely(desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT))) { 2159 vq_err(vq, "Nested indirect descriptor: idx %d, %zx\n", 2160 i, (size_t)vhost64_to_cpu(vq, indirect->addr) + i * sizeof desc); 2161 return -EINVAL; 2162 } 2163 2164 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE)) 2165 access = VHOST_ACCESS_WO; 2166 else 2167 access = VHOST_ACCESS_RO; 2168 2169 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr), 2170 vhost32_to_cpu(vq, desc.len), iov + iov_count, 2171 iov_size - iov_count, access); 2172 if (unlikely(ret < 0)) { 2173 if (ret != -EAGAIN) 2174 vq_err(vq, "Translation failure %d indirect idx %d\n", 2175 ret, i); 2176 return ret; 2177 } 2178 /* If this is an input descriptor, increment that count. */ 2179 if (access == VHOST_ACCESS_WO) { 2180 *in_num += ret; 2181 if (unlikely(log && ret)) { 2182 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr); 2183 log[*log_num].len = vhost32_to_cpu(vq, desc.len); 2184 ++*log_num; 2185 } 2186 } else { 2187 /* If it's an output descriptor, they're all supposed 2188 * to come before any input descriptors. */ 2189 if (unlikely(*in_num)) { 2190 vq_err(vq, "Indirect descriptor " 2191 "has out after in: idx %d\n", i); 2192 return -EINVAL; 2193 } 2194 *out_num += ret; 2195 } 2196 } while ((i = next_desc(vq, &desc)) != -1); 2197 return 0; 2198 } 2199 2200 /* This looks in the virtqueue and for the first available buffer, and converts 2201 * it to an iovec for convenient access. Since descriptors consist of some 2202 * number of output then some number of input descriptors, it's actually two 2203 * iovecs, but we pack them into one and note how many of each there were. 2204 * 2205 * This function returns the descriptor number found, or vq->num (which is 2206 * never a valid descriptor number) if none was found. A negative code is 2207 * returned on error. */ 2208 int vhost_get_vq_desc(struct vhost_virtqueue *vq, 2209 struct iovec iov[], unsigned int iov_size, 2210 unsigned int *out_num, unsigned int *in_num, 2211 struct vhost_log *log, unsigned int *log_num) 2212 { 2213 struct vring_desc desc; 2214 unsigned int i, head, found = 0; 2215 u16 last_avail_idx; 2216 __virtio16 avail_idx; 2217 __virtio16 ring_head; 2218 int ret, access; 2219 2220 /* Check it isn't doing very strange things with descriptor numbers. */ 2221 last_avail_idx = vq->last_avail_idx; 2222 2223 if (vq->avail_idx == vq->last_avail_idx) { 2224 if (unlikely(vhost_get_avail_idx(vq, &avail_idx))) { 2225 vq_err(vq, "Failed to access avail idx at %p\n", 2226 &vq->avail->idx); 2227 return -EFAULT; 2228 } 2229 vq->avail_idx = vhost16_to_cpu(vq, avail_idx); 2230 2231 if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) { 2232 vq_err(vq, "Guest moved used index from %u to %u", 2233 last_avail_idx, vq->avail_idx); 2234 return -EFAULT; 2235 } 2236 2237 /* If there's nothing new since last we looked, return 2238 * invalid. 2239 */ 2240 if (vq->avail_idx == last_avail_idx) 2241 return vq->num; 2242 2243 /* Only get avail ring entries after they have been 2244 * exposed by guest. 2245 */ 2246 smp_rmb(); 2247 } 2248 2249 /* Grab the next descriptor number they're advertising, and increment 2250 * the index we've seen. */ 2251 if (unlikely(vhost_get_avail_head(vq, &ring_head, last_avail_idx))) { 2252 vq_err(vq, "Failed to read head: idx %d address %p\n", 2253 last_avail_idx, 2254 &vq->avail->ring[last_avail_idx % vq->num]); 2255 return -EFAULT; 2256 } 2257 2258 head = vhost16_to_cpu(vq, ring_head); 2259 2260 /* If their number is silly, that's an error. */ 2261 if (unlikely(head >= vq->num)) { 2262 vq_err(vq, "Guest says index %u > %u is available", 2263 head, vq->num); 2264 return -EINVAL; 2265 } 2266 2267 /* When we start there are none of either input nor output. */ 2268 *out_num = *in_num = 0; 2269 if (unlikely(log)) 2270 *log_num = 0; 2271 2272 i = head; 2273 do { 2274 unsigned iov_count = *in_num + *out_num; 2275 if (unlikely(i >= vq->num)) { 2276 vq_err(vq, "Desc index is %u > %u, head = %u", 2277 i, vq->num, head); 2278 return -EINVAL; 2279 } 2280 if (unlikely(++found > vq->num)) { 2281 vq_err(vq, "Loop detected: last one at %u " 2282 "vq size %u head %u\n", 2283 i, vq->num, head); 2284 return -EINVAL; 2285 } 2286 ret = vhost_get_desc(vq, &desc, i); 2287 if (unlikely(ret)) { 2288 vq_err(vq, "Failed to get descriptor: idx %d addr %p\n", 2289 i, vq->desc + i); 2290 return -EFAULT; 2291 } 2292 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT)) { 2293 ret = get_indirect(vq, iov, iov_size, 2294 out_num, in_num, 2295 log, log_num, &desc); 2296 if (unlikely(ret < 0)) { 2297 if (ret != -EAGAIN) 2298 vq_err(vq, "Failure detected " 2299 "in indirect descriptor at idx %d\n", i); 2300 return ret; 2301 } 2302 continue; 2303 } 2304 2305 if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE)) 2306 access = VHOST_ACCESS_WO; 2307 else 2308 access = VHOST_ACCESS_RO; 2309 ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr), 2310 vhost32_to_cpu(vq, desc.len), iov + iov_count, 2311 iov_size - iov_count, access); 2312 if (unlikely(ret < 0)) { 2313 if (ret != -EAGAIN) 2314 vq_err(vq, "Translation failure %d descriptor idx %d\n", 2315 ret, i); 2316 return ret; 2317 } 2318 if (access == VHOST_ACCESS_WO) { 2319 /* If this is an input descriptor, 2320 * increment that count. */ 2321 *in_num += ret; 2322 if (unlikely(log && ret)) { 2323 log[*log_num].addr = vhost64_to_cpu(vq, desc.addr); 2324 log[*log_num].len = vhost32_to_cpu(vq, desc.len); 2325 ++*log_num; 2326 } 2327 } else { 2328 /* If it's an output descriptor, they're all supposed 2329 * to come before any input descriptors. */ 2330 if (unlikely(*in_num)) { 2331 vq_err(vq, "Descriptor has out after in: " 2332 "idx %d\n", i); 2333 return -EINVAL; 2334 } 2335 *out_num += ret; 2336 } 2337 } while ((i = next_desc(vq, &desc)) != -1); 2338 2339 /* On success, increment avail index. */ 2340 vq->last_avail_idx++; 2341 2342 /* Assume notifications from guest are disabled at this point, 2343 * if they aren't we would need to update avail_event index. */ 2344 BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY)); 2345 return head; 2346 } 2347 EXPORT_SYMBOL_GPL(vhost_get_vq_desc); 2348 2349 /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */ 2350 void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n) 2351 { 2352 vq->last_avail_idx -= n; 2353 } 2354 EXPORT_SYMBOL_GPL(vhost_discard_vq_desc); 2355 2356 /* After we've used one of their buffers, we tell them about it. We'll then 2357 * want to notify the guest, using eventfd. */ 2358 int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len) 2359 { 2360 struct vring_used_elem heads = { 2361 cpu_to_vhost32(vq, head), 2362 cpu_to_vhost32(vq, len) 2363 }; 2364 2365 return vhost_add_used_n(vq, &heads, 1); 2366 } 2367 EXPORT_SYMBOL_GPL(vhost_add_used); 2368 2369 static int __vhost_add_used_n(struct vhost_virtqueue *vq, 2370 struct vring_used_elem *heads, 2371 unsigned count) 2372 { 2373 vring_used_elem_t __user *used; 2374 u16 old, new; 2375 int start; 2376 2377 start = vq->last_used_idx & (vq->num - 1); 2378 used = vq->used->ring + start; 2379 if (vhost_put_used(vq, heads, start, count)) { 2380 vq_err(vq, "Failed to write used"); 2381 return -EFAULT; 2382 } 2383 if (unlikely(vq->log_used)) { 2384 /* Make sure data is seen before log. */ 2385 smp_wmb(); 2386 /* Log used ring entry write. */ 2387 log_used(vq, ((void __user *)used - (void __user *)vq->used), 2388 count * sizeof *used); 2389 } 2390 old = vq->last_used_idx; 2391 new = (vq->last_used_idx += count); 2392 /* If the driver never bothers to signal in a very long while, 2393 * used index might wrap around. If that happens, invalidate 2394 * signalled_used index we stored. TODO: make sure driver 2395 * signals at least once in 2^16 and remove this. */ 2396 if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old))) 2397 vq->signalled_used_valid = false; 2398 return 0; 2399 } 2400 2401 /* After we've used one of their buffers, we tell them about it. We'll then 2402 * want to notify the guest, using eventfd. */ 2403 int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads, 2404 unsigned count) 2405 { 2406 int start, n, r; 2407 2408 start = vq->last_used_idx & (vq->num - 1); 2409 n = vq->num - start; 2410 if (n < count) { 2411 r = __vhost_add_used_n(vq, heads, n); 2412 if (r < 0) 2413 return r; 2414 heads += n; 2415 count -= n; 2416 } 2417 r = __vhost_add_used_n(vq, heads, count); 2418 2419 /* Make sure buffer is written before we update index. */ 2420 smp_wmb(); 2421 if (vhost_put_used_idx(vq)) { 2422 vq_err(vq, "Failed to increment used idx"); 2423 return -EFAULT; 2424 } 2425 if (unlikely(vq->log_used)) { 2426 /* Make sure used idx is seen before log. */ 2427 smp_wmb(); 2428 /* Log used index update. */ 2429 log_used(vq, offsetof(struct vring_used, idx), 2430 sizeof vq->used->idx); 2431 if (vq->log_ctx) 2432 eventfd_signal(vq->log_ctx, 1); 2433 } 2434 return r; 2435 } 2436 EXPORT_SYMBOL_GPL(vhost_add_used_n); 2437 2438 static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) 2439 { 2440 __u16 old, new; 2441 __virtio16 event; 2442 bool v; 2443 /* Flush out used index updates. This is paired 2444 * with the barrier that the Guest executes when enabling 2445 * interrupts. */ 2446 smp_mb(); 2447 2448 if (vhost_has_feature(vq, VIRTIO_F_NOTIFY_ON_EMPTY) && 2449 unlikely(vq->avail_idx == vq->last_avail_idx)) 2450 return true; 2451 2452 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) { 2453 __virtio16 flags; 2454 if (vhost_get_avail_flags(vq, &flags)) { 2455 vq_err(vq, "Failed to get flags"); 2456 return true; 2457 } 2458 return !(flags & cpu_to_vhost16(vq, VRING_AVAIL_F_NO_INTERRUPT)); 2459 } 2460 old = vq->signalled_used; 2461 v = vq->signalled_used_valid; 2462 new = vq->signalled_used = vq->last_used_idx; 2463 vq->signalled_used_valid = true; 2464 2465 if (unlikely(!v)) 2466 return true; 2467 2468 if (vhost_get_used_event(vq, &event)) { 2469 vq_err(vq, "Failed to get used event idx"); 2470 return true; 2471 } 2472 return vring_need_event(vhost16_to_cpu(vq, event), new, old); 2473 } 2474 2475 /* This actually signals the guest, using eventfd. */ 2476 void vhost_signal(struct vhost_dev *dev, struct vhost_virtqueue *vq) 2477 { 2478 /* Signal the Guest tell them we used something up. */ 2479 if (vq->call_ctx.ctx && vhost_notify(dev, vq)) 2480 eventfd_signal(vq->call_ctx.ctx, 1); 2481 } 2482 EXPORT_SYMBOL_GPL(vhost_signal); 2483 2484 /* And here's the combo meal deal. Supersize me! */ 2485 void vhost_add_used_and_signal(struct vhost_dev *dev, 2486 struct vhost_virtqueue *vq, 2487 unsigned int head, int len) 2488 { 2489 vhost_add_used(vq, head, len); 2490 vhost_signal(dev, vq); 2491 } 2492 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal); 2493 2494 /* multi-buffer version of vhost_add_used_and_signal */ 2495 void vhost_add_used_and_signal_n(struct vhost_dev *dev, 2496 struct vhost_virtqueue *vq, 2497 struct vring_used_elem *heads, unsigned count) 2498 { 2499 vhost_add_used_n(vq, heads, count); 2500 vhost_signal(dev, vq); 2501 } 2502 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n); 2503 2504 /* return true if we're sure that avaiable ring is empty */ 2505 bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq) 2506 { 2507 __virtio16 avail_idx; 2508 int r; 2509 2510 if (vq->avail_idx != vq->last_avail_idx) 2511 return false; 2512 2513 r = vhost_get_avail_idx(vq, &avail_idx); 2514 if (unlikely(r)) 2515 return false; 2516 vq->avail_idx = vhost16_to_cpu(vq, avail_idx); 2517 2518 return vq->avail_idx == vq->last_avail_idx; 2519 } 2520 EXPORT_SYMBOL_GPL(vhost_vq_avail_empty); 2521 2522 /* OK, now we need to know about added descriptors. */ 2523 bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) 2524 { 2525 __virtio16 avail_idx; 2526 int r; 2527 2528 if (!(vq->used_flags & VRING_USED_F_NO_NOTIFY)) 2529 return false; 2530 vq->used_flags &= ~VRING_USED_F_NO_NOTIFY; 2531 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) { 2532 r = vhost_update_used_flags(vq); 2533 if (r) { 2534 vq_err(vq, "Failed to enable notification at %p: %d\n", 2535 &vq->used->flags, r); 2536 return false; 2537 } 2538 } else { 2539 r = vhost_update_avail_event(vq); 2540 if (r) { 2541 vq_err(vq, "Failed to update avail event index at %p: %d\n", 2542 vhost_avail_event(vq), r); 2543 return false; 2544 } 2545 } 2546 /* They could have slipped one in as we were doing that: make 2547 * sure it's written, then check again. */ 2548 smp_mb(); 2549 r = vhost_get_avail_idx(vq, &avail_idx); 2550 if (r) { 2551 vq_err(vq, "Failed to check avail idx at %p: %d\n", 2552 &vq->avail->idx, r); 2553 return false; 2554 } 2555 vq->avail_idx = vhost16_to_cpu(vq, avail_idx); 2556 2557 return vq->avail_idx != vq->last_avail_idx; 2558 } 2559 EXPORT_SYMBOL_GPL(vhost_enable_notify); 2560 2561 /* We don't need to be notified again. */ 2562 void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) 2563 { 2564 int r; 2565 2566 if (vq->used_flags & VRING_USED_F_NO_NOTIFY) 2567 return; 2568 vq->used_flags |= VRING_USED_F_NO_NOTIFY; 2569 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) { 2570 r = vhost_update_used_flags(vq); 2571 if (r) 2572 vq_err(vq, "Failed to disable notification at %p: %d\n", 2573 &vq->used->flags, r); 2574 } 2575 } 2576 EXPORT_SYMBOL_GPL(vhost_disable_notify); 2577 2578 /* Create a new message. */ 2579 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type) 2580 { 2581 struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL); 2582 if (!node) 2583 return NULL; 2584 2585 /* Make sure all padding within the structure is initialized. */ 2586 memset(&node->msg, 0, sizeof node->msg); 2587 node->vq = vq; 2588 node->msg.type = type; 2589 return node; 2590 } 2591 EXPORT_SYMBOL_GPL(vhost_new_msg); 2592 2593 void vhost_enqueue_msg(struct vhost_dev *dev, struct list_head *head, 2594 struct vhost_msg_node *node) 2595 { 2596 spin_lock(&dev->iotlb_lock); 2597 list_add_tail(&node->node, head); 2598 spin_unlock(&dev->iotlb_lock); 2599 2600 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM); 2601 } 2602 EXPORT_SYMBOL_GPL(vhost_enqueue_msg); 2603 2604 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev, 2605 struct list_head *head) 2606 { 2607 struct vhost_msg_node *node = NULL; 2608 2609 spin_lock(&dev->iotlb_lock); 2610 if (!list_empty(head)) { 2611 node = list_first_entry(head, struct vhost_msg_node, 2612 node); 2613 list_del(&node->node); 2614 } 2615 spin_unlock(&dev->iotlb_lock); 2616 2617 return node; 2618 } 2619 EXPORT_SYMBOL_GPL(vhost_dequeue_msg); 2620 2621 void vhost_set_backend_features(struct vhost_dev *dev, u64 features) 2622 { 2623 struct vhost_virtqueue *vq; 2624 int i; 2625 2626 mutex_lock(&dev->mutex); 2627 for (i = 0; i < dev->nvqs; ++i) { 2628 vq = dev->vqs[i]; 2629 mutex_lock(&vq->mutex); 2630 vq->acked_backend_features = features; 2631 mutex_unlock(&vq->mutex); 2632 } 2633 mutex_unlock(&dev->mutex); 2634 } 2635 EXPORT_SYMBOL_GPL(vhost_set_backend_features); 2636 2637 static int __init vhost_init(void) 2638 { 2639 return 0; 2640 } 2641 2642 static void __exit vhost_exit(void) 2643 { 2644 } 2645 2646 module_init(vhost_init); 2647 module_exit(vhost_exit); 2648 2649 MODULE_VERSION("0.0.1"); 2650 MODULE_LICENSE("GPL v2"); 2651 MODULE_AUTHOR("Michael S. Tsirkin"); 2652 MODULE_DESCRIPTION("Host kernel accelerator for virtio"); 2653