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/mmu_context.h> 18 #include <linux/miscdevice.h> 19 #include <linux/mutex.h> 20 #include <linux/poll.h> 21 #include <linux/file.h> 22 #include <linux/highmem.h> 23 #include <linux/slab.h> 24 #include <linux/vmalloc.h> 25 #include <linux/kthread.h> 26 #include <linux/cgroup.h> 27 #include <linux/module.h> 28 #include <linux/sort.h> 29 #include <linux/sched/mm.h> 30 #include <linux/sched/signal.h> 31 #include <linux/interval_tree_generic.h> 32 #include <linux/nospec.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 INTERVAL_TREE_DEFINE(struct vhost_umem_node, 53 rb, __u64, __subtree_last, 54 START, LAST, static inline, vhost_umem_interval_tree); 55 56 #ifdef CONFIG_VHOST_CROSS_ENDIAN_LEGACY 57 static void vhost_disable_cross_endian(struct vhost_virtqueue *vq) 58 { 59 vq->user_be = !virtio_legacy_is_little_endian(); 60 } 61 62 static void vhost_enable_cross_endian_big(struct vhost_virtqueue *vq) 63 { 64 vq->user_be = true; 65 } 66 67 static void vhost_enable_cross_endian_little(struct vhost_virtqueue *vq) 68 { 69 vq->user_be = false; 70 } 71 72 static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp) 73 { 74 struct vhost_vring_state s; 75 76 if (vq->private_data) 77 return -EBUSY; 78 79 if (copy_from_user(&s, argp, sizeof(s))) 80 return -EFAULT; 81 82 if (s.num != VHOST_VRING_LITTLE_ENDIAN && 83 s.num != VHOST_VRING_BIG_ENDIAN) 84 return -EINVAL; 85 86 if (s.num == VHOST_VRING_BIG_ENDIAN) 87 vhost_enable_cross_endian_big(vq); 88 else 89 vhost_enable_cross_endian_little(vq); 90 91 return 0; 92 } 93 94 static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx, 95 int __user *argp) 96 { 97 struct vhost_vring_state s = { 98 .index = idx, 99 .num = vq->user_be 100 }; 101 102 if (copy_to_user(argp, &s, sizeof(s))) 103 return -EFAULT; 104 105 return 0; 106 } 107 108 static void vhost_init_is_le(struct vhost_virtqueue *vq) 109 { 110 /* Note for legacy virtio: user_be is initialized at reset time 111 * according to the host endianness. If userspace does not set an 112 * explicit endianness, the default behavior is native endian, as 113 * expected by legacy virtio. 114 */ 115 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1) || !vq->user_be; 116 } 117 #else 118 static void vhost_disable_cross_endian(struct vhost_virtqueue *vq) 119 { 120 } 121 122 static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp) 123 { 124 return -ENOIOCTLCMD; 125 } 126 127 static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx, 128 int __user *argp) 129 { 130 return -ENOIOCTLCMD; 131 } 132 133 static void vhost_init_is_le(struct vhost_virtqueue *vq) 134 { 135 vq->is_le = vhost_has_feature(vq, VIRTIO_F_VERSION_1) 136 || virtio_legacy_is_little_endian(); 137 } 138 #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */ 139 140 static void vhost_reset_is_le(struct vhost_virtqueue *vq) 141 { 142 vhost_init_is_le(vq); 143 } 144 145 struct vhost_flush_struct { 146 struct vhost_work work; 147 struct completion wait_event; 148 }; 149 150 static void vhost_flush_work(struct vhost_work *work) 151 { 152 struct vhost_flush_struct *s; 153 154 s = container_of(work, struct vhost_flush_struct, work); 155 complete(&s->wait_event); 156 } 157 158 static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh, 159 poll_table *pt) 160 { 161 struct vhost_poll *poll; 162 163 poll = container_of(pt, struct vhost_poll, table); 164 poll->wqh = wqh; 165 add_wait_queue(wqh, &poll->wait); 166 } 167 168 static int vhost_poll_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync, 169 void *key) 170 { 171 struct vhost_poll *poll = container_of(wait, struct vhost_poll, wait); 172 173 if (!(key_to_poll(key) & poll->mask)) 174 return 0; 175 176 vhost_poll_queue(poll); 177 return 0; 178 } 179 180 void vhost_work_init(struct vhost_work *work, vhost_work_fn_t fn) 181 { 182 clear_bit(VHOST_WORK_QUEUED, &work->flags); 183 work->fn = fn; 184 } 185 EXPORT_SYMBOL_GPL(vhost_work_init); 186 187 /* Init poll structure */ 188 void vhost_poll_init(struct vhost_poll *poll, vhost_work_fn_t fn, 189 __poll_t mask, struct vhost_dev *dev) 190 { 191 init_waitqueue_func_entry(&poll->wait, vhost_poll_wakeup); 192 init_poll_funcptr(&poll->table, vhost_poll_func); 193 poll->mask = mask; 194 poll->dev = dev; 195 poll->wqh = NULL; 196 197 vhost_work_init(&poll->work, fn); 198 } 199 EXPORT_SYMBOL_GPL(vhost_poll_init); 200 201 /* Start polling a file. We add ourselves to file's wait queue. The caller must 202 * keep a reference to a file until after vhost_poll_stop is called. */ 203 int vhost_poll_start(struct vhost_poll *poll, struct file *file) 204 { 205 __poll_t mask; 206 207 if (poll->wqh) 208 return 0; 209 210 mask = vfs_poll(file, &poll->table); 211 if (mask) 212 vhost_poll_wakeup(&poll->wait, 0, 0, poll_to_key(mask)); 213 if (mask & EPOLLERR) { 214 vhost_poll_stop(poll); 215 return -EINVAL; 216 } 217 218 return 0; 219 } 220 EXPORT_SYMBOL_GPL(vhost_poll_start); 221 222 /* Stop polling a file. After this function returns, it becomes safe to drop the 223 * file reference. You must also flush afterwards. */ 224 void vhost_poll_stop(struct vhost_poll *poll) 225 { 226 if (poll->wqh) { 227 remove_wait_queue(poll->wqh, &poll->wait); 228 poll->wqh = NULL; 229 } 230 } 231 EXPORT_SYMBOL_GPL(vhost_poll_stop); 232 233 void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work) 234 { 235 struct vhost_flush_struct flush; 236 237 if (dev->worker) { 238 init_completion(&flush.wait_event); 239 vhost_work_init(&flush.work, vhost_flush_work); 240 241 vhost_work_queue(dev, &flush.work); 242 wait_for_completion(&flush.wait_event); 243 } 244 } 245 EXPORT_SYMBOL_GPL(vhost_work_flush); 246 247 /* Flush any work that has been scheduled. When calling this, don't hold any 248 * locks that are also used by the callback. */ 249 void vhost_poll_flush(struct vhost_poll *poll) 250 { 251 vhost_work_flush(poll->dev, &poll->work); 252 } 253 EXPORT_SYMBOL_GPL(vhost_poll_flush); 254 255 void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work) 256 { 257 if (!dev->worker) 258 return; 259 260 if (!test_and_set_bit(VHOST_WORK_QUEUED, &work->flags)) { 261 /* We can only add the work to the list after we're 262 * sure it was not in the list. 263 * test_and_set_bit() implies a memory barrier. 264 */ 265 llist_add(&work->node, &dev->work_list); 266 wake_up_process(dev->worker); 267 } 268 } 269 EXPORT_SYMBOL_GPL(vhost_work_queue); 270 271 /* A lockless hint for busy polling code to exit the loop */ 272 bool vhost_has_work(struct vhost_dev *dev) 273 { 274 return !llist_empty(&dev->work_list); 275 } 276 EXPORT_SYMBOL_GPL(vhost_has_work); 277 278 void vhost_poll_queue(struct vhost_poll *poll) 279 { 280 vhost_work_queue(poll->dev, &poll->work); 281 } 282 EXPORT_SYMBOL_GPL(vhost_poll_queue); 283 284 static void __vhost_vq_meta_reset(struct vhost_virtqueue *vq) 285 { 286 int j; 287 288 for (j = 0; j < VHOST_NUM_ADDRS; j++) 289 vq->meta_iotlb[j] = NULL; 290 } 291 292 static void vhost_vq_meta_reset(struct vhost_dev *d) 293 { 294 int i; 295 296 for (i = 0; i < d->nvqs; ++i) 297 __vhost_vq_meta_reset(d->vqs[i]); 298 } 299 300 static void vhost_vq_reset(struct vhost_dev *dev, 301 struct vhost_virtqueue *vq) 302 { 303 vq->num = 1; 304 vq->desc = NULL; 305 vq->avail = NULL; 306 vq->used = NULL; 307 vq->last_avail_idx = 0; 308 vq->avail_idx = 0; 309 vq->last_used_idx = 0; 310 vq->signalled_used = 0; 311 vq->signalled_used_valid = false; 312 vq->used_flags = 0; 313 vq->log_used = false; 314 vq->log_addr = -1ull; 315 vq->private_data = NULL; 316 vq->acked_features = 0; 317 vq->acked_backend_features = 0; 318 vq->log_base = NULL; 319 vq->error_ctx = NULL; 320 vq->kick = NULL; 321 vq->call_ctx = NULL; 322 vq->log_ctx = NULL; 323 vhost_reset_is_le(vq); 324 vhost_disable_cross_endian(vq); 325 vq->busyloop_timeout = 0; 326 vq->umem = NULL; 327 vq->iotlb = NULL; 328 __vhost_vq_meta_reset(vq); 329 } 330 331 static int vhost_worker(void *data) 332 { 333 struct vhost_dev *dev = data; 334 struct vhost_work *work, *work_next; 335 struct llist_node *node; 336 mm_segment_t oldfs = get_fs(); 337 338 set_fs(USER_DS); 339 use_mm(dev->mm); 340 341 for (;;) { 342 /* mb paired w/ kthread_stop */ 343 set_current_state(TASK_INTERRUPTIBLE); 344 345 if (kthread_should_stop()) { 346 __set_current_state(TASK_RUNNING); 347 break; 348 } 349 350 node = llist_del_all(&dev->work_list); 351 if (!node) 352 schedule(); 353 354 node = llist_reverse_order(node); 355 /* make sure flag is seen after deletion */ 356 smp_wmb(); 357 llist_for_each_entry_safe(work, work_next, node, node) { 358 clear_bit(VHOST_WORK_QUEUED, &work->flags); 359 __set_current_state(TASK_RUNNING); 360 work->fn(work); 361 if (need_resched()) 362 schedule(); 363 } 364 } 365 unuse_mm(dev->mm); 366 set_fs(oldfs); 367 return 0; 368 } 369 370 static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq) 371 { 372 kfree(vq->indirect); 373 vq->indirect = NULL; 374 kfree(vq->log); 375 vq->log = NULL; 376 kfree(vq->heads); 377 vq->heads = NULL; 378 } 379 380 /* Helper to allocate iovec buffers for all vqs. */ 381 static long vhost_dev_alloc_iovecs(struct vhost_dev *dev) 382 { 383 struct vhost_virtqueue *vq; 384 int i; 385 386 for (i = 0; i < dev->nvqs; ++i) { 387 vq = dev->vqs[i]; 388 vq->indirect = kmalloc_array(UIO_MAXIOV, 389 sizeof(*vq->indirect), 390 GFP_KERNEL); 391 vq->log = kmalloc_array(dev->iov_limit, sizeof(*vq->log), 392 GFP_KERNEL); 393 vq->heads = kmalloc_array(dev->iov_limit, sizeof(*vq->heads), 394 GFP_KERNEL); 395 if (!vq->indirect || !vq->log || !vq->heads) 396 goto err_nomem; 397 } 398 return 0; 399 400 err_nomem: 401 for (; i >= 0; --i) 402 vhost_vq_free_iovecs(dev->vqs[i]); 403 return -ENOMEM; 404 } 405 406 static void vhost_dev_free_iovecs(struct vhost_dev *dev) 407 { 408 int i; 409 410 for (i = 0; i < dev->nvqs; ++i) 411 vhost_vq_free_iovecs(dev->vqs[i]); 412 } 413 414 bool vhost_exceeds_weight(struct vhost_virtqueue *vq, 415 int pkts, int total_len) 416 { 417 struct vhost_dev *dev = vq->dev; 418 419 if ((dev->byte_weight && total_len >= dev->byte_weight) || 420 pkts >= dev->weight) { 421 vhost_poll_queue(&vq->poll); 422 return true; 423 } 424 425 return false; 426 } 427 EXPORT_SYMBOL_GPL(vhost_exceeds_weight); 428 429 static size_t vhost_get_avail_size(struct vhost_virtqueue *vq, 430 unsigned int num) 431 { 432 size_t event __maybe_unused = 433 vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; 434 435 return sizeof(*vq->avail) + 436 sizeof(*vq->avail->ring) * num + event; 437 } 438 439 static size_t vhost_get_used_size(struct vhost_virtqueue *vq, 440 unsigned int num) 441 { 442 size_t event __maybe_unused = 443 vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; 444 445 return sizeof(*vq->used) + 446 sizeof(*vq->used->ring) * num + event; 447 } 448 449 static size_t vhost_get_desc_size(struct vhost_virtqueue *vq, 450 unsigned int num) 451 { 452 return sizeof(*vq->desc) * num; 453 } 454 455 void vhost_dev_init(struct vhost_dev *dev, 456 struct vhost_virtqueue **vqs, int nvqs, 457 int iov_limit, int weight, int byte_weight) 458 { 459 struct vhost_virtqueue *vq; 460 int i; 461 462 dev->vqs = vqs; 463 dev->nvqs = nvqs; 464 mutex_init(&dev->mutex); 465 dev->log_ctx = NULL; 466 dev->umem = NULL; 467 dev->iotlb = NULL; 468 dev->mm = NULL; 469 dev->worker = NULL; 470 dev->iov_limit = iov_limit; 471 dev->weight = weight; 472 dev->byte_weight = byte_weight; 473 init_llist_head(&dev->work_list); 474 init_waitqueue_head(&dev->wait); 475 INIT_LIST_HEAD(&dev->read_list); 476 INIT_LIST_HEAD(&dev->pending_list); 477 spin_lock_init(&dev->iotlb_lock); 478 479 480 for (i = 0; i < dev->nvqs; ++i) { 481 vq = dev->vqs[i]; 482 vq->log = NULL; 483 vq->indirect = NULL; 484 vq->heads = NULL; 485 vq->dev = dev; 486 mutex_init(&vq->mutex); 487 vhost_vq_reset(dev, vq); 488 if (vq->handle_kick) 489 vhost_poll_init(&vq->poll, vq->handle_kick, 490 EPOLLIN, dev); 491 } 492 } 493 EXPORT_SYMBOL_GPL(vhost_dev_init); 494 495 /* Caller should have device mutex */ 496 long vhost_dev_check_owner(struct vhost_dev *dev) 497 { 498 /* Are you the owner? If not, I don't think you mean to do that */ 499 return dev->mm == current->mm ? 0 : -EPERM; 500 } 501 EXPORT_SYMBOL_GPL(vhost_dev_check_owner); 502 503 struct vhost_attach_cgroups_struct { 504 struct vhost_work work; 505 struct task_struct *owner; 506 int ret; 507 }; 508 509 static void vhost_attach_cgroups_work(struct vhost_work *work) 510 { 511 struct vhost_attach_cgroups_struct *s; 512 513 s = container_of(work, struct vhost_attach_cgroups_struct, work); 514 s->ret = cgroup_attach_task_all(s->owner, current); 515 } 516 517 static int vhost_attach_cgroups(struct vhost_dev *dev) 518 { 519 struct vhost_attach_cgroups_struct attach; 520 521 attach.owner = current; 522 vhost_work_init(&attach.work, vhost_attach_cgroups_work); 523 vhost_work_queue(dev, &attach.work); 524 vhost_work_flush(dev, &attach.work); 525 return attach.ret; 526 } 527 528 /* Caller should have device mutex */ 529 bool vhost_dev_has_owner(struct vhost_dev *dev) 530 { 531 return dev->mm; 532 } 533 EXPORT_SYMBOL_GPL(vhost_dev_has_owner); 534 535 /* Caller should have device mutex */ 536 long vhost_dev_set_owner(struct vhost_dev *dev) 537 { 538 struct task_struct *worker; 539 int err; 540 541 /* Is there an owner already? */ 542 if (vhost_dev_has_owner(dev)) { 543 err = -EBUSY; 544 goto err_mm; 545 } 546 547 /* No owner, become one */ 548 dev->mm = get_task_mm(current); 549 worker = kthread_create(vhost_worker, dev, "vhost-%d", current->pid); 550 if (IS_ERR(worker)) { 551 err = PTR_ERR(worker); 552 goto err_worker; 553 } 554 555 dev->worker = worker; 556 wake_up_process(worker); /* avoid contributing to loadavg */ 557 558 err = vhost_attach_cgroups(dev); 559 if (err) 560 goto err_cgroup; 561 562 err = vhost_dev_alloc_iovecs(dev); 563 if (err) 564 goto err_cgroup; 565 566 return 0; 567 err_cgroup: 568 kthread_stop(worker); 569 dev->worker = NULL; 570 err_worker: 571 if (dev->mm) 572 mmput(dev->mm); 573 dev->mm = NULL; 574 err_mm: 575 return err; 576 } 577 EXPORT_SYMBOL_GPL(vhost_dev_set_owner); 578 579 struct vhost_umem *vhost_dev_reset_owner_prepare(void) 580 { 581 return kvzalloc(sizeof(struct vhost_umem), GFP_KERNEL); 582 } 583 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare); 584 585 /* Caller should have device mutex */ 586 void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_umem *umem) 587 { 588 int i; 589 590 vhost_dev_cleanup(dev); 591 592 /* Restore memory to default empty mapping. */ 593 INIT_LIST_HEAD(&umem->umem_list); 594 dev->umem = umem; 595 /* We don't need VQ locks below since vhost_dev_cleanup makes sure 596 * VQs aren't running. 597 */ 598 for (i = 0; i < dev->nvqs; ++i) 599 dev->vqs[i]->umem = umem; 600 } 601 EXPORT_SYMBOL_GPL(vhost_dev_reset_owner); 602 603 void vhost_dev_stop(struct vhost_dev *dev) 604 { 605 int i; 606 607 for (i = 0; i < dev->nvqs; ++i) { 608 if (dev->vqs[i]->kick && dev->vqs[i]->handle_kick) { 609 vhost_poll_stop(&dev->vqs[i]->poll); 610 vhost_poll_flush(&dev->vqs[i]->poll); 611 } 612 } 613 } 614 EXPORT_SYMBOL_GPL(vhost_dev_stop); 615 616 static void vhost_umem_free(struct vhost_umem *umem, 617 struct vhost_umem_node *node) 618 { 619 vhost_umem_interval_tree_remove(node, &umem->umem_tree); 620 list_del(&node->link); 621 kfree(node); 622 umem->numem--; 623 } 624 625 static void vhost_umem_clean(struct vhost_umem *umem) 626 { 627 struct vhost_umem_node *node, *tmp; 628 629 if (!umem) 630 return; 631 632 list_for_each_entry_safe(node, tmp, &umem->umem_list, link) 633 vhost_umem_free(umem, node); 634 635 kvfree(umem); 636 } 637 638 static void vhost_clear_msg(struct vhost_dev *dev) 639 { 640 struct vhost_msg_node *node, *n; 641 642 spin_lock(&dev->iotlb_lock); 643 644 list_for_each_entry_safe(node, n, &dev->read_list, node) { 645 list_del(&node->node); 646 kfree(node); 647 } 648 649 list_for_each_entry_safe(node, n, &dev->pending_list, node) { 650 list_del(&node->node); 651 kfree(node); 652 } 653 654 spin_unlock(&dev->iotlb_lock); 655 } 656 657 void vhost_dev_cleanup(struct vhost_dev *dev) 658 { 659 int i; 660 661 for (i = 0; i < dev->nvqs; ++i) { 662 if (dev->vqs[i]->error_ctx) 663 eventfd_ctx_put(dev->vqs[i]->error_ctx); 664 if (dev->vqs[i]->kick) 665 fput(dev->vqs[i]->kick); 666 if (dev->vqs[i]->call_ctx) 667 eventfd_ctx_put(dev->vqs[i]->call_ctx); 668 vhost_vq_reset(dev, dev->vqs[i]); 669 } 670 vhost_dev_free_iovecs(dev); 671 if (dev->log_ctx) 672 eventfd_ctx_put(dev->log_ctx); 673 dev->log_ctx = NULL; 674 /* No one will access memory at this point */ 675 vhost_umem_clean(dev->umem); 676 dev->umem = NULL; 677 vhost_umem_clean(dev->iotlb); 678 dev->iotlb = NULL; 679 vhost_clear_msg(dev); 680 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM); 681 WARN_ON(!llist_empty(&dev->work_list)); 682 if (dev->worker) { 683 kthread_stop(dev->worker); 684 dev->worker = NULL; 685 } 686 if (dev->mm) 687 mmput(dev->mm); 688 dev->mm = NULL; 689 } 690 EXPORT_SYMBOL_GPL(vhost_dev_cleanup); 691 692 static bool log_access_ok(void __user *log_base, u64 addr, unsigned long sz) 693 { 694 u64 a = addr / VHOST_PAGE_SIZE / 8; 695 696 /* Make sure 64 bit math will not overflow. */ 697 if (a > ULONG_MAX - (unsigned long)log_base || 698 a + (unsigned long)log_base > ULONG_MAX) 699 return false; 700 701 return access_ok(log_base + a, 702 (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8); 703 } 704 705 static bool vhost_overflow(u64 uaddr, u64 size) 706 { 707 /* Make sure 64 bit math will not overflow. */ 708 return uaddr > ULONG_MAX || size > ULONG_MAX || uaddr > ULONG_MAX - size; 709 } 710 711 /* Caller should have vq mutex and device mutex. */ 712 static bool vq_memory_access_ok(void __user *log_base, struct vhost_umem *umem, 713 int log_all) 714 { 715 struct vhost_umem_node *node; 716 717 if (!umem) 718 return false; 719 720 list_for_each_entry(node, &umem->umem_list, link) { 721 unsigned long a = node->userspace_addr; 722 723 if (vhost_overflow(node->userspace_addr, node->size)) 724 return false; 725 726 727 if (!access_ok((void __user *)a, 728 node->size)) 729 return false; 730 else if (log_all && !log_access_ok(log_base, 731 node->start, 732 node->size)) 733 return false; 734 } 735 return true; 736 } 737 738 static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq, 739 u64 addr, unsigned int size, 740 int type) 741 { 742 const struct vhost_umem_node *node = vq->meta_iotlb[type]; 743 744 if (!node) 745 return NULL; 746 747 return (void *)(uintptr_t)(node->userspace_addr + addr - node->start); 748 } 749 750 /* Can we switch to this memory table? */ 751 /* Caller should have device mutex but not vq mutex */ 752 static bool memory_access_ok(struct vhost_dev *d, struct vhost_umem *umem, 753 int log_all) 754 { 755 int i; 756 757 for (i = 0; i < d->nvqs; ++i) { 758 bool ok; 759 bool log; 760 761 mutex_lock(&d->vqs[i]->mutex); 762 log = log_all || vhost_has_feature(d->vqs[i], VHOST_F_LOG_ALL); 763 /* If ring is inactive, will check when it's enabled. */ 764 if (d->vqs[i]->private_data) 765 ok = vq_memory_access_ok(d->vqs[i]->log_base, 766 umem, log); 767 else 768 ok = true; 769 mutex_unlock(&d->vqs[i]->mutex); 770 if (!ok) 771 return false; 772 } 773 return true; 774 } 775 776 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len, 777 struct iovec iov[], int iov_size, int access); 778 779 static int vhost_copy_to_user(struct vhost_virtqueue *vq, void __user *to, 780 const void *from, unsigned size) 781 { 782 int ret; 783 784 if (!vq->iotlb) 785 return __copy_to_user(to, from, size); 786 else { 787 /* This function should be called after iotlb 788 * prefetch, which means we're sure that all vq 789 * could be access through iotlb. So -EAGAIN should 790 * not happen in this case. 791 */ 792 struct iov_iter t; 793 void __user *uaddr = vhost_vq_meta_fetch(vq, 794 (u64)(uintptr_t)to, size, 795 VHOST_ADDR_USED); 796 797 if (uaddr) 798 return __copy_to_user(uaddr, from, size); 799 800 ret = translate_desc(vq, (u64)(uintptr_t)to, size, vq->iotlb_iov, 801 ARRAY_SIZE(vq->iotlb_iov), 802 VHOST_ACCESS_WO); 803 if (ret < 0) 804 goto out; 805 iov_iter_init(&t, WRITE, vq->iotlb_iov, ret, size); 806 ret = copy_to_iter(from, size, &t); 807 if (ret == size) 808 ret = 0; 809 } 810 out: 811 return ret; 812 } 813 814 static int vhost_copy_from_user(struct vhost_virtqueue *vq, void *to, 815 void __user *from, unsigned size) 816 { 817 int ret; 818 819 if (!vq->iotlb) 820 return __copy_from_user(to, from, size); 821 else { 822 /* This function should be called after iotlb 823 * prefetch, which means we're sure that vq 824 * could be access through iotlb. So -EAGAIN should 825 * not happen in this case. 826 */ 827 void __user *uaddr = vhost_vq_meta_fetch(vq, 828 (u64)(uintptr_t)from, size, 829 VHOST_ADDR_DESC); 830 struct iov_iter f; 831 832 if (uaddr) 833 return __copy_from_user(to, uaddr, size); 834 835 ret = translate_desc(vq, (u64)(uintptr_t)from, size, vq->iotlb_iov, 836 ARRAY_SIZE(vq->iotlb_iov), 837 VHOST_ACCESS_RO); 838 if (ret < 0) { 839 vq_err(vq, "IOTLB translation failure: uaddr " 840 "%p size 0x%llx\n", from, 841 (unsigned long long) size); 842 goto out; 843 } 844 iov_iter_init(&f, READ, vq->iotlb_iov, ret, size); 845 ret = copy_from_iter(to, size, &f); 846 if (ret == size) 847 ret = 0; 848 } 849 850 out: 851 return ret; 852 } 853 854 static void __user *__vhost_get_user_slow(struct vhost_virtqueue *vq, 855 void __user *addr, unsigned int size, 856 int type) 857 { 858 int ret; 859 860 ret = translate_desc(vq, (u64)(uintptr_t)addr, size, vq->iotlb_iov, 861 ARRAY_SIZE(vq->iotlb_iov), 862 VHOST_ACCESS_RO); 863 if (ret < 0) { 864 vq_err(vq, "IOTLB translation failure: uaddr " 865 "%p size 0x%llx\n", addr, 866 (unsigned long long) size); 867 return NULL; 868 } 869 870 if (ret != 1 || vq->iotlb_iov[0].iov_len != size) { 871 vq_err(vq, "Non atomic userspace memory access: uaddr " 872 "%p size 0x%llx\n", addr, 873 (unsigned long long) size); 874 return NULL; 875 } 876 877 return vq->iotlb_iov[0].iov_base; 878 } 879 880 /* This function should be called after iotlb 881 * prefetch, which means we're sure that vq 882 * could be access through iotlb. So -EAGAIN should 883 * not happen in this case. 884 */ 885 static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq, 886 void *addr, unsigned int size, 887 int type) 888 { 889 void __user *uaddr = vhost_vq_meta_fetch(vq, 890 (u64)(uintptr_t)addr, size, type); 891 if (uaddr) 892 return uaddr; 893 894 return __vhost_get_user_slow(vq, addr, size, type); 895 } 896 897 #define vhost_put_user(vq, x, ptr) \ 898 ({ \ 899 int ret = -EFAULT; \ 900 if (!vq->iotlb) { \ 901 ret = __put_user(x, ptr); \ 902 } else { \ 903 __typeof__(ptr) to = \ 904 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \ 905 sizeof(*ptr), VHOST_ADDR_USED); \ 906 if (to != NULL) \ 907 ret = __put_user(x, to); \ 908 else \ 909 ret = -EFAULT; \ 910 } \ 911 ret; \ 912 }) 913 914 static inline int vhost_put_avail_event(struct vhost_virtqueue *vq) 915 { 916 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx), 917 vhost_avail_event(vq)); 918 } 919 920 static inline int vhost_put_used(struct vhost_virtqueue *vq, 921 struct vring_used_elem *head, int idx, 922 int count) 923 { 924 return vhost_copy_to_user(vq, vq->used->ring + idx, head, 925 count * sizeof(*head)); 926 } 927 928 static inline int vhost_put_used_flags(struct vhost_virtqueue *vq) 929 930 { 931 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags), 932 &vq->used->flags); 933 } 934 935 static inline int vhost_put_used_idx(struct vhost_virtqueue *vq) 936 937 { 938 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx), 939 &vq->used->idx); 940 } 941 942 #define vhost_get_user(vq, x, ptr, type) \ 943 ({ \ 944 int ret; \ 945 if (!vq->iotlb) { \ 946 ret = __get_user(x, ptr); \ 947 } else { \ 948 __typeof__(ptr) from = \ 949 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \ 950 sizeof(*ptr), \ 951 type); \ 952 if (from != NULL) \ 953 ret = __get_user(x, from); \ 954 else \ 955 ret = -EFAULT; \ 956 } \ 957 ret; \ 958 }) 959 960 #define vhost_get_avail(vq, x, ptr) \ 961 vhost_get_user(vq, x, ptr, VHOST_ADDR_AVAIL) 962 963 #define vhost_get_used(vq, x, ptr) \ 964 vhost_get_user(vq, x, ptr, VHOST_ADDR_USED) 965 966 static void vhost_dev_lock_vqs(struct vhost_dev *d) 967 { 968 int i = 0; 969 for (i = 0; i < d->nvqs; ++i) 970 mutex_lock_nested(&d->vqs[i]->mutex, i); 971 } 972 973 static void vhost_dev_unlock_vqs(struct vhost_dev *d) 974 { 975 int i = 0; 976 for (i = 0; i < d->nvqs; ++i) 977 mutex_unlock(&d->vqs[i]->mutex); 978 } 979 980 static inline int vhost_get_avail_idx(struct vhost_virtqueue *vq, 981 __virtio16 *idx) 982 { 983 return vhost_get_avail(vq, *idx, &vq->avail->idx); 984 } 985 986 static inline int vhost_get_avail_head(struct vhost_virtqueue *vq, 987 __virtio16 *head, int idx) 988 { 989 return vhost_get_avail(vq, *head, 990 &vq->avail->ring[idx & (vq->num - 1)]); 991 } 992 993 static inline int vhost_get_avail_flags(struct vhost_virtqueue *vq, 994 __virtio16 *flags) 995 { 996 return vhost_get_avail(vq, *flags, &vq->avail->flags); 997 } 998 999 static inline int vhost_get_used_event(struct vhost_virtqueue *vq, 1000 __virtio16 *event) 1001 { 1002 return vhost_get_avail(vq, *event, vhost_used_event(vq)); 1003 } 1004 1005 static inline int vhost_get_used_idx(struct vhost_virtqueue *vq, 1006 __virtio16 *idx) 1007 { 1008 return vhost_get_used(vq, *idx, &vq->used->idx); 1009 } 1010 1011 static inline int vhost_get_desc(struct vhost_virtqueue *vq, 1012 struct vring_desc *desc, int idx) 1013 { 1014 return vhost_copy_from_user(vq, desc, vq->desc + idx, sizeof(*desc)); 1015 } 1016 1017 static int vhost_new_umem_range(struct vhost_umem *umem, 1018 u64 start, u64 size, u64 end, 1019 u64 userspace_addr, int perm) 1020 { 1021 struct vhost_umem_node *tmp, *node; 1022 1023 if (!size) 1024 return -EFAULT; 1025 1026 node = kmalloc(sizeof(*node), GFP_ATOMIC); 1027 if (!node) 1028 return -ENOMEM; 1029 1030 if (umem->numem == max_iotlb_entries) { 1031 tmp = list_first_entry(&umem->umem_list, typeof(*tmp), link); 1032 vhost_umem_free(umem, tmp); 1033 } 1034 1035 node->start = start; 1036 node->size = size; 1037 node->last = end; 1038 node->userspace_addr = userspace_addr; 1039 node->perm = perm; 1040 INIT_LIST_HEAD(&node->link); 1041 list_add_tail(&node->link, &umem->umem_list); 1042 vhost_umem_interval_tree_insert(node, &umem->umem_tree); 1043 umem->numem++; 1044 1045 return 0; 1046 } 1047 1048 static void vhost_del_umem_range(struct vhost_umem *umem, 1049 u64 start, u64 end) 1050 { 1051 struct vhost_umem_node *node; 1052 1053 while ((node = vhost_umem_interval_tree_iter_first(&umem->umem_tree, 1054 start, end))) 1055 vhost_umem_free(umem, node); 1056 } 1057 1058 static void vhost_iotlb_notify_vq(struct vhost_dev *d, 1059 struct vhost_iotlb_msg *msg) 1060 { 1061 struct vhost_msg_node *node, *n; 1062 1063 spin_lock(&d->iotlb_lock); 1064 1065 list_for_each_entry_safe(node, n, &d->pending_list, node) { 1066 struct vhost_iotlb_msg *vq_msg = &node->msg.iotlb; 1067 if (msg->iova <= vq_msg->iova && 1068 msg->iova + msg->size - 1 >= vq_msg->iova && 1069 vq_msg->type == VHOST_IOTLB_MISS) { 1070 vhost_poll_queue(&node->vq->poll); 1071 list_del(&node->node); 1072 kfree(node); 1073 } 1074 } 1075 1076 spin_unlock(&d->iotlb_lock); 1077 } 1078 1079 static bool umem_access_ok(u64 uaddr, u64 size, int access) 1080 { 1081 unsigned long a = uaddr; 1082 1083 /* Make sure 64 bit math will not overflow. */ 1084 if (vhost_overflow(uaddr, size)) 1085 return false; 1086 1087 if ((access & VHOST_ACCESS_RO) && 1088 !access_ok((void __user *)a, size)) 1089 return false; 1090 if ((access & VHOST_ACCESS_WO) && 1091 !access_ok((void __user *)a, size)) 1092 return false; 1093 return true; 1094 } 1095 1096 static int vhost_process_iotlb_msg(struct vhost_dev *dev, 1097 struct vhost_iotlb_msg *msg) 1098 { 1099 int ret = 0; 1100 1101 mutex_lock(&dev->mutex); 1102 vhost_dev_lock_vqs(dev); 1103 switch (msg->type) { 1104 case VHOST_IOTLB_UPDATE: 1105 if (!dev->iotlb) { 1106 ret = -EFAULT; 1107 break; 1108 } 1109 if (!umem_access_ok(msg->uaddr, msg->size, msg->perm)) { 1110 ret = -EFAULT; 1111 break; 1112 } 1113 vhost_vq_meta_reset(dev); 1114 if (vhost_new_umem_range(dev->iotlb, msg->iova, msg->size, 1115 msg->iova + msg->size - 1, 1116 msg->uaddr, msg->perm)) { 1117 ret = -ENOMEM; 1118 break; 1119 } 1120 vhost_iotlb_notify_vq(dev, msg); 1121 break; 1122 case VHOST_IOTLB_INVALIDATE: 1123 if (!dev->iotlb) { 1124 ret = -EFAULT; 1125 break; 1126 } 1127 vhost_vq_meta_reset(dev); 1128 vhost_del_umem_range(dev->iotlb, msg->iova, 1129 msg->iova + msg->size - 1); 1130 break; 1131 default: 1132 ret = -EINVAL; 1133 break; 1134 } 1135 1136 vhost_dev_unlock_vqs(dev); 1137 mutex_unlock(&dev->mutex); 1138 1139 return ret; 1140 } 1141 ssize_t vhost_chr_write_iter(struct vhost_dev *dev, 1142 struct iov_iter *from) 1143 { 1144 struct vhost_iotlb_msg msg; 1145 size_t offset; 1146 int type, ret; 1147 1148 ret = copy_from_iter(&type, sizeof(type), from); 1149 if (ret != sizeof(type)) { 1150 ret = -EINVAL; 1151 goto done; 1152 } 1153 1154 switch (type) { 1155 case VHOST_IOTLB_MSG: 1156 /* There maybe a hole after type for V1 message type, 1157 * so skip it here. 1158 */ 1159 offset = offsetof(struct vhost_msg, iotlb) - sizeof(int); 1160 break; 1161 case VHOST_IOTLB_MSG_V2: 1162 offset = sizeof(__u32); 1163 break; 1164 default: 1165 ret = -EINVAL; 1166 goto done; 1167 } 1168 1169 iov_iter_advance(from, offset); 1170 ret = copy_from_iter(&msg, sizeof(msg), from); 1171 if (ret != sizeof(msg)) { 1172 ret = -EINVAL; 1173 goto done; 1174 } 1175 if (vhost_process_iotlb_msg(dev, &msg)) { 1176 ret = -EFAULT; 1177 goto done; 1178 } 1179 1180 ret = (type == VHOST_IOTLB_MSG) ? sizeof(struct vhost_msg) : 1181 sizeof(struct vhost_msg_v2); 1182 done: 1183 return ret; 1184 } 1185 EXPORT_SYMBOL(vhost_chr_write_iter); 1186 1187 __poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev, 1188 poll_table *wait) 1189 { 1190 __poll_t mask = 0; 1191 1192 poll_wait(file, &dev->wait, wait); 1193 1194 if (!list_empty(&dev->read_list)) 1195 mask |= EPOLLIN | EPOLLRDNORM; 1196 1197 return mask; 1198 } 1199 EXPORT_SYMBOL(vhost_chr_poll); 1200 1201 ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to, 1202 int noblock) 1203 { 1204 DEFINE_WAIT(wait); 1205 struct vhost_msg_node *node; 1206 ssize_t ret = 0; 1207 unsigned size = sizeof(struct vhost_msg); 1208 1209 if (iov_iter_count(to) < size) 1210 return 0; 1211 1212 while (1) { 1213 if (!noblock) 1214 prepare_to_wait(&dev->wait, &wait, 1215 TASK_INTERRUPTIBLE); 1216 1217 node = vhost_dequeue_msg(dev, &dev->read_list); 1218 if (node) 1219 break; 1220 if (noblock) { 1221 ret = -EAGAIN; 1222 break; 1223 } 1224 if (signal_pending(current)) { 1225 ret = -ERESTARTSYS; 1226 break; 1227 } 1228 if (!dev->iotlb) { 1229 ret = -EBADFD; 1230 break; 1231 } 1232 1233 schedule(); 1234 } 1235 1236 if (!noblock) 1237 finish_wait(&dev->wait, &wait); 1238 1239 if (node) { 1240 struct vhost_iotlb_msg *msg; 1241 void *start = &node->msg; 1242 1243 switch (node->msg.type) { 1244 case VHOST_IOTLB_MSG: 1245 size = sizeof(node->msg); 1246 msg = &node->msg.iotlb; 1247 break; 1248 case VHOST_IOTLB_MSG_V2: 1249 size = sizeof(node->msg_v2); 1250 msg = &node->msg_v2.iotlb; 1251 break; 1252 default: 1253 BUG(); 1254 break; 1255 } 1256 1257 ret = copy_to_iter(start, size, to); 1258 if (ret != size || msg->type != VHOST_IOTLB_MISS) { 1259 kfree(node); 1260 return ret; 1261 } 1262 vhost_enqueue_msg(dev, &dev->pending_list, node); 1263 } 1264 1265 return ret; 1266 } 1267 EXPORT_SYMBOL_GPL(vhost_chr_read_iter); 1268 1269 static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access) 1270 { 1271 struct vhost_dev *dev = vq->dev; 1272 struct vhost_msg_node *node; 1273 struct vhost_iotlb_msg *msg; 1274 bool v2 = vhost_backend_has_feature(vq, VHOST_BACKEND_F_IOTLB_MSG_V2); 1275 1276 node = vhost_new_msg(vq, v2 ? VHOST_IOTLB_MSG_V2 : VHOST_IOTLB_MSG); 1277 if (!node) 1278 return -ENOMEM; 1279 1280 if (v2) { 1281 node->msg_v2.type = VHOST_IOTLB_MSG_V2; 1282 msg = &node->msg_v2.iotlb; 1283 } else { 1284 msg = &node->msg.iotlb; 1285 } 1286 1287 msg->type = VHOST_IOTLB_MISS; 1288 msg->iova = iova; 1289 msg->perm = access; 1290 1291 vhost_enqueue_msg(dev, &dev->read_list, node); 1292 1293 return 0; 1294 } 1295 1296 static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num, 1297 struct vring_desc __user *desc, 1298 struct vring_avail __user *avail, 1299 struct vring_used __user *used) 1300 1301 { 1302 return access_ok(desc, vhost_get_desc_size(vq, num)) && 1303 access_ok(avail, vhost_get_avail_size(vq, num)) && 1304 access_ok(used, vhost_get_used_size(vq, num)); 1305 } 1306 1307 static void vhost_vq_meta_update(struct vhost_virtqueue *vq, 1308 const struct vhost_umem_node *node, 1309 int type) 1310 { 1311 int access = (type == VHOST_ADDR_USED) ? 1312 VHOST_ACCESS_WO : VHOST_ACCESS_RO; 1313 1314 if (likely(node->perm & access)) 1315 vq->meta_iotlb[type] = node; 1316 } 1317 1318 static bool iotlb_access_ok(struct vhost_virtqueue *vq, 1319 int access, u64 addr, u64 len, int type) 1320 { 1321 const struct vhost_umem_node *node; 1322 struct vhost_umem *umem = vq->iotlb; 1323 u64 s = 0, size, orig_addr = addr, last = addr + len - 1; 1324 1325 if (vhost_vq_meta_fetch(vq, addr, len, type)) 1326 return true; 1327 1328 while (len > s) { 1329 node = vhost_umem_interval_tree_iter_first(&umem->umem_tree, 1330 addr, 1331 last); 1332 if (node == NULL || node->start > addr) { 1333 vhost_iotlb_miss(vq, addr, access); 1334 return false; 1335 } else if (!(node->perm & access)) { 1336 /* Report the possible access violation by 1337 * request another translation from userspace. 1338 */ 1339 return false; 1340 } 1341 1342 size = node->size - addr + node->start; 1343 1344 if (orig_addr == addr && size >= len) 1345 vhost_vq_meta_update(vq, node, type); 1346 1347 s += size; 1348 addr += size; 1349 } 1350 1351 return true; 1352 } 1353 1354 int vq_meta_prefetch(struct vhost_virtqueue *vq) 1355 { 1356 unsigned int num = vq->num; 1357 1358 if (!vq->iotlb) 1359 return 1; 1360 1361 return iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->desc, 1362 vhost_get_desc_size(vq, num), VHOST_ADDR_DESC) && 1363 iotlb_access_ok(vq, VHOST_ACCESS_RO, (u64)(uintptr_t)vq->avail, 1364 vhost_get_avail_size(vq, num), 1365 VHOST_ADDR_AVAIL) && 1366 iotlb_access_ok(vq, VHOST_ACCESS_WO, (u64)(uintptr_t)vq->used, 1367 vhost_get_used_size(vq, num), VHOST_ADDR_USED); 1368 } 1369 EXPORT_SYMBOL_GPL(vq_meta_prefetch); 1370 1371 /* Can we log writes? */ 1372 /* Caller should have device mutex but not vq mutex */ 1373 bool vhost_log_access_ok(struct vhost_dev *dev) 1374 { 1375 return memory_access_ok(dev, dev->umem, 1); 1376 } 1377 EXPORT_SYMBOL_GPL(vhost_log_access_ok); 1378 1379 /* Verify access for write logging. */ 1380 /* Caller should have vq mutex and device mutex */ 1381 static bool vq_log_access_ok(struct vhost_virtqueue *vq, 1382 void __user *log_base) 1383 { 1384 return vq_memory_access_ok(log_base, vq->umem, 1385 vhost_has_feature(vq, VHOST_F_LOG_ALL)) && 1386 (!vq->log_used || log_access_ok(log_base, vq->log_addr, 1387 vhost_get_used_size(vq, vq->num))); 1388 } 1389 1390 /* Can we start vq? */ 1391 /* Caller should have vq mutex and device mutex */ 1392 bool vhost_vq_access_ok(struct vhost_virtqueue *vq) 1393 { 1394 if (!vq_log_access_ok(vq, vq->log_base)) 1395 return false; 1396 1397 /* Access validation occurs at prefetch time with IOTLB */ 1398 if (vq->iotlb) 1399 return true; 1400 1401 return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used); 1402 } 1403 EXPORT_SYMBOL_GPL(vhost_vq_access_ok); 1404 1405 static struct vhost_umem *vhost_umem_alloc(void) 1406 { 1407 struct vhost_umem *umem = kvzalloc(sizeof(*umem), GFP_KERNEL); 1408 1409 if (!umem) 1410 return NULL; 1411 1412 umem->umem_tree = RB_ROOT_CACHED; 1413 umem->numem = 0; 1414 INIT_LIST_HEAD(&umem->umem_list); 1415 1416 return umem; 1417 } 1418 1419 static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) 1420 { 1421 struct vhost_memory mem, *newmem; 1422 struct vhost_memory_region *region; 1423 struct vhost_umem *newumem, *oldumem; 1424 unsigned long size = offsetof(struct vhost_memory, regions); 1425 int i; 1426 1427 if (copy_from_user(&mem, m, size)) 1428 return -EFAULT; 1429 if (mem.padding) 1430 return -EOPNOTSUPP; 1431 if (mem.nregions > max_mem_regions) 1432 return -E2BIG; 1433 newmem = kvzalloc(struct_size(newmem, regions, mem.nregions), 1434 GFP_KERNEL); 1435 if (!newmem) 1436 return -ENOMEM; 1437 1438 memcpy(newmem, &mem, size); 1439 if (copy_from_user(newmem->regions, m->regions, 1440 mem.nregions * sizeof *m->regions)) { 1441 kvfree(newmem); 1442 return -EFAULT; 1443 } 1444 1445 newumem = vhost_umem_alloc(); 1446 if (!newumem) { 1447 kvfree(newmem); 1448 return -ENOMEM; 1449 } 1450 1451 for (region = newmem->regions; 1452 region < newmem->regions + mem.nregions; 1453 region++) { 1454 if (vhost_new_umem_range(newumem, 1455 region->guest_phys_addr, 1456 region->memory_size, 1457 region->guest_phys_addr + 1458 region->memory_size - 1, 1459 region->userspace_addr, 1460 VHOST_ACCESS_RW)) 1461 goto err; 1462 } 1463 1464 if (!memory_access_ok(d, newumem, 0)) 1465 goto err; 1466 1467 oldumem = d->umem; 1468 d->umem = newumem; 1469 1470 /* All memory accesses are done under some VQ mutex. */ 1471 for (i = 0; i < d->nvqs; ++i) { 1472 mutex_lock(&d->vqs[i]->mutex); 1473 d->vqs[i]->umem = newumem; 1474 mutex_unlock(&d->vqs[i]->mutex); 1475 } 1476 1477 kvfree(newmem); 1478 vhost_umem_clean(oldumem); 1479 return 0; 1480 1481 err: 1482 vhost_umem_clean(newumem); 1483 kvfree(newmem); 1484 return -EFAULT; 1485 } 1486 1487 static long vhost_vring_set_num(struct vhost_dev *d, 1488 struct vhost_virtqueue *vq, 1489 void __user *argp) 1490 { 1491 struct vhost_vring_state s; 1492 1493 /* Resizing ring with an active backend? 1494 * You don't want to do that. */ 1495 if (vq->private_data) 1496 return -EBUSY; 1497 1498 if (copy_from_user(&s, argp, sizeof s)) 1499 return -EFAULT; 1500 1501 if (!s.num || s.num > 0xffff || (s.num & (s.num - 1))) 1502 return -EINVAL; 1503 vq->num = s.num; 1504 1505 return 0; 1506 } 1507 1508 static long vhost_vring_set_addr(struct vhost_dev *d, 1509 struct vhost_virtqueue *vq, 1510 void __user *argp) 1511 { 1512 struct vhost_vring_addr a; 1513 1514 if (copy_from_user(&a, argp, sizeof a)) 1515 return -EFAULT; 1516 if (a.flags & ~(0x1 << VHOST_VRING_F_LOG)) 1517 return -EOPNOTSUPP; 1518 1519 /* For 32bit, verify that the top 32bits of the user 1520 data are set to zero. */ 1521 if ((u64)(unsigned long)a.desc_user_addr != a.desc_user_addr || 1522 (u64)(unsigned long)a.used_user_addr != a.used_user_addr || 1523 (u64)(unsigned long)a.avail_user_addr != a.avail_user_addr) 1524 return -EFAULT; 1525 1526 /* Make sure it's safe to cast pointers to vring types. */ 1527 BUILD_BUG_ON(__alignof__ *vq->avail > VRING_AVAIL_ALIGN_SIZE); 1528 BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE); 1529 if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) || 1530 (a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) || 1531 (a.log_guest_addr & (VRING_USED_ALIGN_SIZE - 1))) 1532 return -EINVAL; 1533 1534 /* We only verify access here if backend is configured. 1535 * If it is not, we don't as size might not have been setup. 1536 * We will verify when backend is configured. */ 1537 if (vq->private_data) { 1538 if (!vq_access_ok(vq, vq->num, 1539 (void __user *)(unsigned long)a.desc_user_addr, 1540 (void __user *)(unsigned long)a.avail_user_addr, 1541 (void __user *)(unsigned long)a.used_user_addr)) 1542 return -EINVAL; 1543 1544 /* Also validate log access for used ring if enabled. */ 1545 if ((a.flags & (0x1 << VHOST_VRING_F_LOG)) && 1546 !log_access_ok(vq->log_base, a.log_guest_addr, 1547 sizeof *vq->used + 1548 vq->num * sizeof *vq->used->ring)) 1549 return -EINVAL; 1550 } 1551 1552 vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG)); 1553 vq->desc = (void __user *)(unsigned long)a.desc_user_addr; 1554 vq->avail = (void __user *)(unsigned long)a.avail_user_addr; 1555 vq->log_addr = a.log_guest_addr; 1556 vq->used = (void __user *)(unsigned long)a.used_user_addr; 1557 1558 return 0; 1559 } 1560 1561 static long vhost_vring_set_num_addr(struct vhost_dev *d, 1562 struct vhost_virtqueue *vq, 1563 unsigned int ioctl, 1564 void __user *argp) 1565 { 1566 long r; 1567 1568 mutex_lock(&vq->mutex); 1569 1570 switch (ioctl) { 1571 case VHOST_SET_VRING_NUM: 1572 r = vhost_vring_set_num(d, vq, argp); 1573 break; 1574 case VHOST_SET_VRING_ADDR: 1575 r = vhost_vring_set_addr(d, vq, argp); 1576 break; 1577 default: 1578 BUG(); 1579 } 1580 1581 mutex_unlock(&vq->mutex); 1582 1583 return r; 1584 } 1585 long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp) 1586 { 1587 struct file *eventfp, *filep = NULL; 1588 bool pollstart = false, pollstop = false; 1589 struct eventfd_ctx *ctx = NULL; 1590 u32 __user *idxp = argp; 1591 struct vhost_virtqueue *vq; 1592 struct vhost_vring_state s; 1593 struct vhost_vring_file f; 1594 u32 idx; 1595 long r; 1596 1597 r = get_user(idx, idxp); 1598 if (r < 0) 1599 return r; 1600 if (idx >= d->nvqs) 1601 return -ENOBUFS; 1602 1603 idx = array_index_nospec(idx, d->nvqs); 1604 vq = d->vqs[idx]; 1605 1606 if (ioctl == VHOST_SET_VRING_NUM || 1607 ioctl == VHOST_SET_VRING_ADDR) { 1608 return vhost_vring_set_num_addr(d, vq, ioctl, argp); 1609 } 1610 1611 mutex_lock(&vq->mutex); 1612 1613 switch (ioctl) { 1614 case VHOST_SET_VRING_BASE: 1615 /* Moving base with an active backend? 1616 * You don't want to do that. */ 1617 if (vq->private_data) { 1618 r = -EBUSY; 1619 break; 1620 } 1621 if (copy_from_user(&s, argp, sizeof s)) { 1622 r = -EFAULT; 1623 break; 1624 } 1625 if (s.num > 0xffff) { 1626 r = -EINVAL; 1627 break; 1628 } 1629 vq->last_avail_idx = s.num; 1630 /* Forget the cached index value. */ 1631 vq->avail_idx = vq->last_avail_idx; 1632 break; 1633 case VHOST_GET_VRING_BASE: 1634 s.index = idx; 1635 s.num = vq->last_avail_idx; 1636 if (copy_to_user(argp, &s, sizeof s)) 1637 r = -EFAULT; 1638 break; 1639 case VHOST_SET_VRING_KICK: 1640 if (copy_from_user(&f, argp, sizeof f)) { 1641 r = -EFAULT; 1642 break; 1643 } 1644 eventfp = f.fd == -1 ? NULL : eventfd_fget(f.fd); 1645 if (IS_ERR(eventfp)) { 1646 r = PTR_ERR(eventfp); 1647 break; 1648 } 1649 if (eventfp != vq->kick) { 1650 pollstop = (filep = vq->kick) != NULL; 1651 pollstart = (vq->kick = eventfp) != NULL; 1652 } else 1653 filep = eventfp; 1654 break; 1655 case VHOST_SET_VRING_CALL: 1656 if (copy_from_user(&f, argp, sizeof f)) { 1657 r = -EFAULT; 1658 break; 1659 } 1660 ctx = f.fd == -1 ? NULL : eventfd_ctx_fdget(f.fd); 1661 if (IS_ERR(ctx)) { 1662 r = PTR_ERR(ctx); 1663 break; 1664 } 1665 swap(ctx, vq->call_ctx); 1666 break; 1667 case VHOST_SET_VRING_ERR: 1668 if (copy_from_user(&f, argp, sizeof f)) { 1669 r = -EFAULT; 1670 break; 1671 } 1672 ctx = f.fd == -1 ? NULL : eventfd_ctx_fdget(f.fd); 1673 if (IS_ERR(ctx)) { 1674 r = PTR_ERR(ctx); 1675 break; 1676 } 1677 swap(ctx, vq->error_ctx); 1678 break; 1679 case VHOST_SET_VRING_ENDIAN: 1680 r = vhost_set_vring_endian(vq, argp); 1681 break; 1682 case VHOST_GET_VRING_ENDIAN: 1683 r = vhost_get_vring_endian(vq, idx, argp); 1684 break; 1685 case VHOST_SET_VRING_BUSYLOOP_TIMEOUT: 1686 if (copy_from_user(&s, argp, sizeof(s))) { 1687 r = -EFAULT; 1688 break; 1689 } 1690 vq->busyloop_timeout = s.num; 1691 break; 1692 case VHOST_GET_VRING_BUSYLOOP_TIMEOUT: 1693 s.index = idx; 1694 s.num = vq->busyloop_timeout; 1695 if (copy_to_user(argp, &s, sizeof(s))) 1696 r = -EFAULT; 1697 break; 1698 default: 1699 r = -ENOIOCTLCMD; 1700 } 1701 1702 if (pollstop && vq->handle_kick) 1703 vhost_poll_stop(&vq->poll); 1704 1705 if (!IS_ERR_OR_NULL(ctx)) 1706 eventfd_ctx_put(ctx); 1707 if (filep) 1708 fput(filep); 1709 1710 if (pollstart && vq->handle_kick) 1711 r = vhost_poll_start(&vq->poll, vq->kick); 1712 1713 mutex_unlock(&vq->mutex); 1714 1715 if (pollstop && vq->handle_kick) 1716 vhost_poll_flush(&vq->poll); 1717 return r; 1718 } 1719 EXPORT_SYMBOL_GPL(vhost_vring_ioctl); 1720 1721 int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled) 1722 { 1723 struct vhost_umem *niotlb, *oiotlb; 1724 int i; 1725 1726 niotlb = vhost_umem_alloc(); 1727 if (!niotlb) 1728 return -ENOMEM; 1729 1730 oiotlb = d->iotlb; 1731 d->iotlb = niotlb; 1732 1733 for (i = 0; i < d->nvqs; ++i) { 1734 struct vhost_virtqueue *vq = d->vqs[i]; 1735 1736 mutex_lock(&vq->mutex); 1737 vq->iotlb = niotlb; 1738 __vhost_vq_meta_reset(vq); 1739 mutex_unlock(&vq->mutex); 1740 } 1741 1742 vhost_umem_clean(oiotlb); 1743 1744 return 0; 1745 } 1746 EXPORT_SYMBOL_GPL(vhost_init_device_iotlb); 1747 1748 /* Caller must have device mutex */ 1749 long vhost_dev_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp) 1750 { 1751 struct eventfd_ctx *ctx; 1752 u64 p; 1753 long r; 1754 int i, fd; 1755 1756 /* If you are not the owner, you can become one */ 1757 if (ioctl == VHOST_SET_OWNER) { 1758 r = vhost_dev_set_owner(d); 1759 goto done; 1760 } 1761 1762 /* You must be the owner to do anything else */ 1763 r = vhost_dev_check_owner(d); 1764 if (r) 1765 goto done; 1766 1767 switch (ioctl) { 1768 case VHOST_SET_MEM_TABLE: 1769 r = vhost_set_memory(d, argp); 1770 break; 1771 case VHOST_SET_LOG_BASE: 1772 if (copy_from_user(&p, argp, sizeof p)) { 1773 r = -EFAULT; 1774 break; 1775 } 1776 if ((u64)(unsigned long)p != p) { 1777 r = -EFAULT; 1778 break; 1779 } 1780 for (i = 0; i < d->nvqs; ++i) { 1781 struct vhost_virtqueue *vq; 1782 void __user *base = (void __user *)(unsigned long)p; 1783 vq = d->vqs[i]; 1784 mutex_lock(&vq->mutex); 1785 /* If ring is inactive, will check when it's enabled. */ 1786 if (vq->private_data && !vq_log_access_ok(vq, base)) 1787 r = -EFAULT; 1788 else 1789 vq->log_base = base; 1790 mutex_unlock(&vq->mutex); 1791 } 1792 break; 1793 case VHOST_SET_LOG_FD: 1794 r = get_user(fd, (int __user *)argp); 1795 if (r < 0) 1796 break; 1797 ctx = fd == -1 ? NULL : eventfd_ctx_fdget(fd); 1798 if (IS_ERR(ctx)) { 1799 r = PTR_ERR(ctx); 1800 break; 1801 } 1802 swap(ctx, d->log_ctx); 1803 for (i = 0; i < d->nvqs; ++i) { 1804 mutex_lock(&d->vqs[i]->mutex); 1805 d->vqs[i]->log_ctx = d->log_ctx; 1806 mutex_unlock(&d->vqs[i]->mutex); 1807 } 1808 if (ctx) 1809 eventfd_ctx_put(ctx); 1810 break; 1811 default: 1812 r = -ENOIOCTLCMD; 1813 break; 1814 } 1815 done: 1816 return r; 1817 } 1818 EXPORT_SYMBOL_GPL(vhost_dev_ioctl); 1819 1820 /* TODO: This is really inefficient. We need something like get_user() 1821 * (instruction directly accesses the data, with an exception table entry 1822 * returning -EFAULT). See Documentation/x86/exception-tables.rst. 1823 */ 1824 static int set_bit_to_user(int nr, void __user *addr) 1825 { 1826 unsigned long log = (unsigned long)addr; 1827 struct page *page; 1828 void *base; 1829 int bit = nr + (log % PAGE_SIZE) * 8; 1830 int r; 1831 1832 r = get_user_pages_fast(log, 1, FOLL_WRITE, &page); 1833 if (r < 0) 1834 return r; 1835 BUG_ON(r != 1); 1836 base = kmap_atomic(page); 1837 set_bit(bit, base); 1838 kunmap_atomic(base); 1839 set_page_dirty_lock(page); 1840 put_page(page); 1841 return 0; 1842 } 1843 1844 static int log_write(void __user *log_base, 1845 u64 write_address, u64 write_length) 1846 { 1847 u64 write_page = write_address / VHOST_PAGE_SIZE; 1848 int r; 1849 1850 if (!write_length) 1851 return 0; 1852 write_length += write_address % VHOST_PAGE_SIZE; 1853 for (;;) { 1854 u64 base = (u64)(unsigned long)log_base; 1855 u64 log = base + write_page / 8; 1856 int bit = write_page % 8; 1857 if ((u64)(unsigned long)log != log) 1858 return -EFAULT; 1859 r = set_bit_to_user(bit, (void __user *)(unsigned long)log); 1860 if (r < 0) 1861 return r; 1862 if (write_length <= VHOST_PAGE_SIZE) 1863 break; 1864 write_length -= VHOST_PAGE_SIZE; 1865 write_page += 1; 1866 } 1867 return r; 1868 } 1869 1870 static int log_write_hva(struct vhost_virtqueue *vq, u64 hva, u64 len) 1871 { 1872 struct vhost_umem *umem = vq->umem; 1873 struct vhost_umem_node *u; 1874 u64 start, end, l, min; 1875 int r; 1876 bool hit = false; 1877 1878 while (len) { 1879 min = len; 1880 /* More than one GPAs can be mapped into a single HVA. So 1881 * iterate all possible umems here to be safe. 1882 */ 1883 list_for_each_entry(u, &umem->umem_list, link) { 1884 if (u->userspace_addr > hva - 1 + len || 1885 u->userspace_addr - 1 + u->size < hva) 1886 continue; 1887 start = max(u->userspace_addr, hva); 1888 end = min(u->userspace_addr - 1 + u->size, 1889 hva - 1 + len); 1890 l = end - start + 1; 1891 r = log_write(vq->log_base, 1892 u->start + start - u->userspace_addr, 1893 l); 1894 if (r < 0) 1895 return r; 1896 hit = true; 1897 min = min(l, min); 1898 } 1899 1900 if (!hit) 1901 return -EFAULT; 1902 1903 len -= min; 1904 hva += min; 1905 } 1906 1907 return 0; 1908 } 1909 1910 static int log_used(struct vhost_virtqueue *vq, u64 used_offset, u64 len) 1911 { 1912 struct iovec iov[64]; 1913 int i, ret; 1914 1915 if (!vq->iotlb) 1916 return log_write(vq->log_base, vq->log_addr + used_offset, len); 1917 1918 ret = translate_desc(vq, (uintptr_t)vq->used + used_offset, 1919 len, iov, 64, VHOST_ACCESS_WO); 1920 if (ret < 0) 1921 return ret; 1922 1923 for (i = 0; i < ret; i++) { 1924 ret = log_write_hva(vq, (uintptr_t)iov[i].iov_base, 1925 iov[i].iov_len); 1926 if (ret) 1927 return ret; 1928 } 1929 1930 return 0; 1931 } 1932 1933 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log, 1934 unsigned int log_num, u64 len, struct iovec *iov, int count) 1935 { 1936 int i, r; 1937 1938 /* Make sure data written is seen before log. */ 1939 smp_wmb(); 1940 1941 if (vq->iotlb) { 1942 for (i = 0; i < count; i++) { 1943 r = log_write_hva(vq, (uintptr_t)iov[i].iov_base, 1944 iov[i].iov_len); 1945 if (r < 0) 1946 return r; 1947 } 1948 return 0; 1949 } 1950 1951 for (i = 0; i < log_num; ++i) { 1952 u64 l = min(log[i].len, len); 1953 r = log_write(vq->log_base, log[i].addr, l); 1954 if (r < 0) 1955 return r; 1956 len -= l; 1957 if (!len) { 1958 if (vq->log_ctx) 1959 eventfd_signal(vq->log_ctx, 1); 1960 return 0; 1961 } 1962 } 1963 /* Length written exceeds what we have stored. This is a bug. */ 1964 BUG(); 1965 return 0; 1966 } 1967 EXPORT_SYMBOL_GPL(vhost_log_write); 1968 1969 static int vhost_update_used_flags(struct vhost_virtqueue *vq) 1970 { 1971 void __user *used; 1972 if (vhost_put_used_flags(vq)) 1973 return -EFAULT; 1974 if (unlikely(vq->log_used)) { 1975 /* Make sure the flag is seen before log. */ 1976 smp_wmb(); 1977 /* Log used flag write. */ 1978 used = &vq->used->flags; 1979 log_used(vq, (used - (void __user *)vq->used), 1980 sizeof vq->used->flags); 1981 if (vq->log_ctx) 1982 eventfd_signal(vq->log_ctx, 1); 1983 } 1984 return 0; 1985 } 1986 1987 static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event) 1988 { 1989 if (vhost_put_avail_event(vq)) 1990 return -EFAULT; 1991 if (unlikely(vq->log_used)) { 1992 void __user *used; 1993 /* Make sure the event is seen before log. */ 1994 smp_wmb(); 1995 /* Log avail event write */ 1996 used = vhost_avail_event(vq); 1997 log_used(vq, (used - (void __user *)vq->used), 1998 sizeof *vhost_avail_event(vq)); 1999 if (vq->log_ctx) 2000 eventfd_signal(vq->log_ctx, 1); 2001 } 2002 return 0; 2003 } 2004 2005 int vhost_vq_init_access(struct vhost_virtqueue *vq) 2006 { 2007 __virtio16 last_used_idx; 2008 int r; 2009 bool is_le = vq->is_le; 2010 2011 if (!vq->private_data) 2012 return 0; 2013 2014 vhost_init_is_le(vq); 2015 2016 r = vhost_update_used_flags(vq); 2017 if (r) 2018 goto err; 2019 vq->signalled_used_valid = false; 2020 if (!vq->iotlb && 2021 !access_ok(&vq->used->idx, sizeof vq->used->idx)) { 2022 r = -EFAULT; 2023 goto err; 2024 } 2025 r = vhost_get_used_idx(vq, &last_used_idx); 2026 if (r) { 2027 vq_err(vq, "Can't access used idx at %p\n", 2028 &vq->used->idx); 2029 goto err; 2030 } 2031 vq->last_used_idx = vhost16_to_cpu(vq, last_used_idx); 2032 return 0; 2033 2034 err: 2035 vq->is_le = is_le; 2036 return r; 2037 } 2038 EXPORT_SYMBOL_GPL(vhost_vq_init_access); 2039 2040 static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len, 2041 struct iovec iov[], int iov_size, int access) 2042 { 2043 const struct vhost_umem_node *node; 2044 struct vhost_dev *dev = vq->dev; 2045 struct vhost_umem *umem = dev->iotlb ? dev->iotlb : dev->umem; 2046 struct iovec *_iov; 2047 u64 s = 0; 2048 int ret = 0; 2049 2050 while ((u64)len > s) { 2051 u64 size; 2052 if (unlikely(ret >= iov_size)) { 2053 ret = -ENOBUFS; 2054 break; 2055 } 2056 2057 node = vhost_umem_interval_tree_iter_first(&umem->umem_tree, 2058 addr, addr + len - 1); 2059 if (node == NULL || node->start > addr) { 2060 if (umem != dev->iotlb) { 2061 ret = -EFAULT; 2062 break; 2063 } 2064 ret = -EAGAIN; 2065 break; 2066 } else if (!(node->perm & access)) { 2067 ret = -EPERM; 2068 break; 2069 } 2070 2071 _iov = iov + ret; 2072 size = node->size - addr + node->start; 2073 _iov->iov_len = min((u64)len - s, size); 2074 _iov->iov_base = (void __user *)(unsigned long) 2075 (node->userspace_addr + addr - node->start); 2076 s += size; 2077 addr += size; 2078 ++ret; 2079 } 2080 2081 if (ret == -EAGAIN) 2082 vhost_iotlb_miss(vq, addr, access); 2083 return ret; 2084 } 2085 2086 /* Each buffer in the virtqueues is actually a chain of descriptors. This 2087 * function returns the next descriptor in the chain, 2088 * or -1U if we're at the end. */ 2089 static unsigned next_desc(struct vhost_virtqueue *vq, struct vring_desc *desc) 2090 { 2091 unsigned int next; 2092 2093 /* If this descriptor says it doesn't chain, we're done. */ 2094 if (!(desc->flags & cpu_to_vhost16(vq, VRING_DESC_F_NEXT))) 2095 return -1U; 2096 2097 /* Check they're not leading us off end of descriptors. */ 2098 next = vhost16_to_cpu(vq, READ_ONCE(desc->next)); 2099 return next; 2100 } 2101 2102 static int get_indirect(struct vhost_virtqueue *vq, 2103 struct iovec iov[], unsigned int iov_size, 2104 unsigned int *out_num, unsigned int *in_num, 2105 struct vhost_log *log, unsigned int *log_num, 2106 struct vring_desc *indirect) 2107 { 2108 struct vring_desc desc; 2109 unsigned int i = 0, count, found = 0; 2110 u32 len = vhost32_to_cpu(vq, indirect->len); 2111 struct iov_iter from; 2112 int ret, access; 2113 2114 /* Sanity check */ 2115 if (unlikely(len % sizeof desc)) { 2116 vq_err(vq, "Invalid length in indirect descriptor: " 2117 "len 0x%llx not multiple of 0x%zx\n", 2118 (unsigned long long)len, 2119 sizeof desc); 2120 return -EINVAL; 2121 } 2122 2123 ret = translate_desc(vq, vhost64_to_cpu(vq, indirect->addr), len, vq->indirect, 2124 UIO_MAXIOV, VHOST_ACCESS_RO); 2125 if (unlikely(ret < 0)) { 2126 if (ret != -EAGAIN) 2127 vq_err(vq, "Translation failure %d in indirect.\n", ret); 2128 return ret; 2129 } 2130 iov_iter_init(&from, READ, vq->indirect, ret, len); 2131 2132 /* We will use the result as an address to read from, so most 2133 * architectures only need a compiler barrier here. */ 2134 read_barrier_depends(); 2135 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 struct vring_used_elem __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 && vhost_notify(dev, vq)) 2480 eventfd_signal(vq->call_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, vq->avail_idx); 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 2556 return vhost16_to_cpu(vq, avail_idx) != vq->avail_idx; 2557 } 2558 EXPORT_SYMBOL_GPL(vhost_enable_notify); 2559 2560 /* We don't need to be notified again. */ 2561 void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq) 2562 { 2563 int r; 2564 2565 if (vq->used_flags & VRING_USED_F_NO_NOTIFY) 2566 return; 2567 vq->used_flags |= VRING_USED_F_NO_NOTIFY; 2568 if (!vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX)) { 2569 r = vhost_update_used_flags(vq); 2570 if (r) 2571 vq_err(vq, "Failed to enable notification at %p: %d\n", 2572 &vq->used->flags, r); 2573 } 2574 } 2575 EXPORT_SYMBOL_GPL(vhost_disable_notify); 2576 2577 /* Create a new message. */ 2578 struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type) 2579 { 2580 struct vhost_msg_node *node = kmalloc(sizeof *node, GFP_KERNEL); 2581 if (!node) 2582 return NULL; 2583 2584 /* Make sure all padding within the structure is initialized. */ 2585 memset(&node->msg, 0, sizeof node->msg); 2586 node->vq = vq; 2587 node->msg.type = type; 2588 return node; 2589 } 2590 EXPORT_SYMBOL_GPL(vhost_new_msg); 2591 2592 void vhost_enqueue_msg(struct vhost_dev *dev, struct list_head *head, 2593 struct vhost_msg_node *node) 2594 { 2595 spin_lock(&dev->iotlb_lock); 2596 list_add_tail(&node->node, head); 2597 spin_unlock(&dev->iotlb_lock); 2598 2599 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM); 2600 } 2601 EXPORT_SYMBOL_GPL(vhost_enqueue_msg); 2602 2603 struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev, 2604 struct list_head *head) 2605 { 2606 struct vhost_msg_node *node = NULL; 2607 2608 spin_lock(&dev->iotlb_lock); 2609 if (!list_empty(head)) { 2610 node = list_first_entry(head, struct vhost_msg_node, 2611 node); 2612 list_del(&node->node); 2613 } 2614 spin_unlock(&dev->iotlb_lock); 2615 2616 return node; 2617 } 2618 EXPORT_SYMBOL_GPL(vhost_dequeue_msg); 2619 2620 2621 static int __init vhost_init(void) 2622 { 2623 return 0; 2624 } 2625 2626 static void __exit vhost_exit(void) 2627 { 2628 } 2629 2630 module_init(vhost_init); 2631 module_exit(vhost_exit); 2632 2633 MODULE_VERSION("0.0.1"); 2634 MODULE_LICENSE("GPL v2"); 2635 MODULE_AUTHOR("Michael S. Tsirkin"); 2636 MODULE_DESCRIPTION("Host kernel accelerator for virtio"); 2637