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/cgroup.h> 26#include <linux/module.h> 27#include <linux/sort.h> 28#include <linux/sched/mm.h> 29#include <linux/sched/signal.h> 30#include <linux/interval_tree_generic.h> 31#include <linux/nospec.h> 32#include <linux/kcov.h> 33 34#include "vhost.h" 35 36static ushort max_mem_regions = 64; 37module_param(max_mem_regions, ushort, 0444); 38MODULE_PARM_DESC(max_mem_regions, 39 "Maximum number of memory regions in memory map. (default: 64)"); 40static int max_iotlb_entries = 2048; 41module_param(max_iotlb_entries, int, 0444); 42MODULE_PARM_DESC(max_iotlb_entries, 43 "Maximum number of iotlb entries. (default: 2048)"); 44 45enum { 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 53static void vhost_disable_cross_endian(struct vhost_virtqueue *vq) 54{ 55 vq->user_be = !virtio_legacy_is_little_endian(); 56} 57 58static void vhost_enable_cross_endian_big(struct vhost_virtqueue *vq) 59{ 60 vq->user_be = true; 61} 62 63static void vhost_enable_cross_endian_little(struct vhost_virtqueue *vq) 64{ 65 vq->user_be = false; 66} 67 68static 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 90static 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 104static 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 114static void vhost_disable_cross_endian(struct vhost_virtqueue *vq) 115{ 116} 117 118static long vhost_set_vring_endian(struct vhost_virtqueue *vq, int __user *argp) 119{ 120 return -ENOIOCTLCMD; 121} 122 123static long vhost_get_vring_endian(struct vhost_virtqueue *vq, u32 idx, 124 int __user *argp) 125{ 126 return -ENOIOCTLCMD; 127} 128 129static 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 136static void vhost_reset_is_le(struct vhost_virtqueue *vq) 137{ 138 vhost_init_is_le(vq); 139} 140 141struct vhost_flush_struct { 142 struct vhost_work work; 143 struct completion wait_event; 144}; 145 146static 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 154static 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 164static 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 181void 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} 186EXPORT_SYMBOL_GPL(vhost_work_init); 187 188/* Init poll structure */ 189void 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} 200EXPORT_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. */ 204int 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} 221EXPORT_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. */ 225void 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} 232EXPORT_SYMBOL_GPL(vhost_poll_stop); 233 234void vhost_work_flush(struct vhost_dev *dev, struct vhost_work *work) 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} 246EXPORT_SYMBOL_GPL(vhost_work_flush); 247 248/* Flush any work that has been scheduled. When calling this, don't hold any 249 * locks that are also used by the callback. */ 250void vhost_poll_flush(struct vhost_poll *poll) 251{ 252 vhost_work_flush(poll->dev, &poll->work); 253} 254EXPORT_SYMBOL_GPL(vhost_poll_flush); 255 256void vhost_work_queue(struct vhost_dev *dev, struct vhost_work *work) 257{ 258 if (!dev->worker) 259 return; 260 261 if (!test_and_set_bit(VHOST_WORK_QUEUED, &work->flags)) { 262 /* We can only add the work to the list after we're 263 * sure it was not in the list. 264 * test_and_set_bit() implies a memory barrier. 265 */ 266 llist_add(&work->node, &dev->work_list); 267 wake_up_process(dev->worker); 268 } 269} 270EXPORT_SYMBOL_GPL(vhost_work_queue); 271 272/* A lockless hint for busy polling code to exit the loop */ 273bool vhost_has_work(struct vhost_dev *dev) 274{ 275 return !llist_empty(&dev->work_list); 276} 277EXPORT_SYMBOL_GPL(vhost_has_work); 278 279void vhost_poll_queue(struct vhost_poll *poll) 280{ 281 vhost_work_queue(poll->dev, &poll->work); 282} 283EXPORT_SYMBOL_GPL(vhost_poll_queue); 284 285static void __vhost_vq_meta_reset(struct vhost_virtqueue *vq) 286{ 287 int j; 288 289 for (j = 0; j < VHOST_NUM_ADDRS; j++) 290 vq->meta_iotlb[j] = NULL; 291} 292 293static void vhost_vq_meta_reset(struct vhost_dev *d) 294{ 295 int i; 296 297 for (i = 0; i < d->nvqs; ++i) 298 __vhost_vq_meta_reset(d->vqs[i]); 299} 300 301static void vhost_vring_call_reset(struct vhost_vring_call *call_ctx) 302{ 303 call_ctx->ctx = NULL; 304 memset(&call_ctx->producer, 0x0, sizeof(struct irq_bypass_producer)); 305} 306 307bool vhost_vq_is_setup(struct vhost_virtqueue *vq) 308{ 309 return vq->avail && vq->desc && vq->used && vhost_vq_access_ok(vq); 310} 311EXPORT_SYMBOL_GPL(vhost_vq_is_setup); 312 313static void vhost_vq_reset(struct vhost_dev *dev, 314 struct vhost_virtqueue *vq) 315{ 316 vq->num = 1; 317 vq->desc = NULL; 318 vq->avail = NULL; 319 vq->used = NULL; 320 vq->last_avail_idx = 0; 321 vq->avail_idx = 0; 322 vq->last_used_idx = 0; 323 vq->signalled_used = 0; 324 vq->signalled_used_valid = false; 325 vq->used_flags = 0; 326 vq->log_used = false; 327 vq->log_addr = -1ull; 328 vq->private_data = NULL; 329 vq->acked_features = 0; 330 vq->acked_backend_features = 0; 331 vq->log_base = NULL; 332 vq->error_ctx = NULL; 333 vq->kick = NULL; 334 vq->log_ctx = NULL; 335 vhost_disable_cross_endian(vq); 336 vhost_reset_is_le(vq); 337 vq->busyloop_timeout = 0; 338 vq->umem = NULL; 339 vq->iotlb = NULL; 340 vhost_vring_call_reset(&vq->call_ctx); 341 __vhost_vq_meta_reset(vq); 342} 343 344static int vhost_worker(void *data) 345{ 346 struct vhost_dev *dev = data; 347 struct vhost_work *work, *work_next; 348 struct llist_node *node; 349 350 kthread_use_mm(dev->mm); 351 352 for (;;) { 353 /* mb paired w/ kthread_stop */ 354 set_current_state(TASK_INTERRUPTIBLE); 355 356 if (kthread_should_stop()) { 357 __set_current_state(TASK_RUNNING); 358 break; 359 } 360 361 node = llist_del_all(&dev->work_list); 362 if (!node) 363 schedule(); 364 365 node = llist_reverse_order(node); 366 /* make sure flag is seen after deletion */ 367 smp_wmb(); 368 llist_for_each_entry_safe(work, work_next, node, node) { 369 clear_bit(VHOST_WORK_QUEUED, &work->flags); 370 __set_current_state(TASK_RUNNING); 371 kcov_remote_start_common(dev->kcov_handle); 372 work->fn(work); 373 kcov_remote_stop(); 374 if (need_resched()) 375 schedule(); 376 } 377 } 378 kthread_unuse_mm(dev->mm); 379 return 0; 380} 381 382static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq) 383{ 384 kfree(vq->indirect); 385 vq->indirect = NULL; 386 kfree(vq->log); 387 vq->log = NULL; 388 kfree(vq->heads); 389 vq->heads = NULL; 390} 391 392/* Helper to allocate iovec buffers for all vqs. */ 393static long vhost_dev_alloc_iovecs(struct vhost_dev *dev) 394{ 395 struct vhost_virtqueue *vq; 396 int i; 397 398 for (i = 0; i < dev->nvqs; ++i) { 399 vq = dev->vqs[i]; 400 vq->indirect = kmalloc_array(UIO_MAXIOV, 401 sizeof(*vq->indirect), 402 GFP_KERNEL); 403 vq->log = kmalloc_array(dev->iov_limit, sizeof(*vq->log), 404 GFP_KERNEL); 405 vq->heads = kmalloc_array(dev->iov_limit, sizeof(*vq->heads), 406 GFP_KERNEL); 407 if (!vq->indirect || !vq->log || !vq->heads) 408 goto err_nomem; 409 } 410 return 0; 411 412err_nomem: 413 for (; i >= 0; --i) 414 vhost_vq_free_iovecs(dev->vqs[i]); 415 return -ENOMEM; 416} 417 418static void vhost_dev_free_iovecs(struct vhost_dev *dev) 419{ 420 int i; 421 422 for (i = 0; i < dev->nvqs; ++i) 423 vhost_vq_free_iovecs(dev->vqs[i]); 424} 425 426bool vhost_exceeds_weight(struct vhost_virtqueue *vq, 427 int pkts, int total_len) 428{ 429 struct vhost_dev *dev = vq->dev; 430 431 if ((dev->byte_weight && total_len >= dev->byte_weight) || 432 pkts >= dev->weight) { 433 vhost_poll_queue(&vq->poll); 434 return true; 435 } 436 437 return false; 438} 439EXPORT_SYMBOL_GPL(vhost_exceeds_weight); 440 441static size_t vhost_get_avail_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->avail) + 448 sizeof(*vq->avail->ring) * num + event; 449} 450 451static size_t vhost_get_used_size(struct vhost_virtqueue *vq, 452 unsigned int num) 453{ 454 size_t event __maybe_unused = 455 vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0; 456 457 return sizeof(*vq->used) + 458 sizeof(*vq->used->ring) * num + event; 459} 460 461static size_t vhost_get_desc_size(struct vhost_virtqueue *vq, 462 unsigned int num) 463{ 464 return sizeof(*vq->desc) * num; 465} 466 467void vhost_dev_init(struct vhost_dev *dev, 468 struct vhost_virtqueue **vqs, int nvqs, 469 int iov_limit, int weight, int byte_weight, 470 bool use_worker, 471 int (*msg_handler)(struct vhost_dev *dev, 472 struct vhost_iotlb_msg *msg)) 473{ 474 struct vhost_virtqueue *vq; 475 int i; 476 477 dev->vqs = vqs; 478 dev->nvqs = nvqs; 479 mutex_init(&dev->mutex); 480 dev->log_ctx = NULL; 481 dev->umem = NULL; 482 dev->iotlb = NULL; 483 dev->mm = NULL; 484 dev->worker = NULL; 485 dev->iov_limit = iov_limit; 486 dev->weight = weight; 487 dev->byte_weight = byte_weight; 488 dev->use_worker = use_worker; 489 dev->msg_handler = msg_handler; 490 init_llist_head(&dev->work_list); 491 init_waitqueue_head(&dev->wait); 492 INIT_LIST_HEAD(&dev->read_list); 493 INIT_LIST_HEAD(&dev->pending_list); 494 spin_lock_init(&dev->iotlb_lock); 495 496 497 for (i = 0; i < dev->nvqs; ++i) { 498 vq = dev->vqs[i]; 499 vq->log = NULL; 500 vq->indirect = NULL; 501 vq->heads = NULL; 502 vq->dev = dev; 503 mutex_init(&vq->mutex); 504 vhost_vq_reset(dev, vq); 505 if (vq->handle_kick) 506 vhost_poll_init(&vq->poll, vq->handle_kick, 507 EPOLLIN, dev); 508 } 509} 510EXPORT_SYMBOL_GPL(vhost_dev_init); 511 512/* Caller should have device mutex */ 513long vhost_dev_check_owner(struct vhost_dev *dev) 514{ 515 /* Are you the owner? If not, I don't think you mean to do that */ 516 return dev->mm == current->mm ? 0 : -EPERM; 517} 518EXPORT_SYMBOL_GPL(vhost_dev_check_owner); 519 520struct vhost_attach_cgroups_struct { 521 struct vhost_work work; 522 struct task_struct *owner; 523 int ret; 524}; 525 526static void vhost_attach_cgroups_work(struct vhost_work *work) 527{ 528 struct vhost_attach_cgroups_struct *s; 529 530 s = container_of(work, struct vhost_attach_cgroups_struct, work); 531 s->ret = cgroup_attach_task_all(s->owner, current); 532} 533 534static int vhost_attach_cgroups(struct vhost_dev *dev) 535{ 536 struct vhost_attach_cgroups_struct attach; 537 538 attach.owner = current; 539 vhost_work_init(&attach.work, vhost_attach_cgroups_work); 540 vhost_work_queue(dev, &attach.work); 541 vhost_work_flush(dev, &attach.work); 542 return attach.ret; 543} 544 545/* Caller should have device mutex */ 546bool vhost_dev_has_owner(struct vhost_dev *dev) 547{ 548 return dev->mm; 549} 550EXPORT_SYMBOL_GPL(vhost_dev_has_owner); 551 552static void vhost_attach_mm(struct vhost_dev *dev) 553{ 554 /* No owner, become one */ 555 if (dev->use_worker) { 556 dev->mm = get_task_mm(current); 557 } else { 558 /* vDPA device does not use worker thead, so there's 559 * no need to hold the address space for mm. This help 560 * to avoid deadlock in the case of mmap() which may 561 * held the refcnt of the file and depends on release 562 * method to remove vma. 563 */ 564 dev->mm = current->mm; 565 mmgrab(dev->mm); 566 } 567} 568 569static void vhost_detach_mm(struct vhost_dev *dev) 570{ 571 if (!dev->mm) 572 return; 573 574 if (dev->use_worker) 575 mmput(dev->mm); 576 else 577 mmdrop(dev->mm); 578 579 dev->mm = NULL; 580} 581 582/* Caller should have device mutex */ 583long vhost_dev_set_owner(struct vhost_dev *dev) 584{ 585 struct task_struct *worker; 586 int err; 587 588 /* Is there an owner already? */ 589 if (vhost_dev_has_owner(dev)) { 590 err = -EBUSY; 591 goto err_mm; 592 } 593 594 vhost_attach_mm(dev); 595 596 dev->kcov_handle = kcov_common_handle(); 597 if (dev->use_worker) { 598 worker = kthread_create(vhost_worker, dev, 599 "vhost-%d", current->pid); 600 if (IS_ERR(worker)) { 601 err = PTR_ERR(worker); 602 goto err_worker; 603 } 604 605 dev->worker = worker; 606 wake_up_process(worker); /* avoid contributing to loadavg */ 607 608 err = vhost_attach_cgroups(dev); 609 if (err) 610 goto err_cgroup; 611 } 612 613 err = vhost_dev_alloc_iovecs(dev); 614 if (err) 615 goto err_cgroup; 616 617 return 0; 618err_cgroup: 619 if (dev->worker) { 620 kthread_stop(dev->worker); 621 dev->worker = NULL; 622 } 623err_worker: 624 vhost_detach_mm(dev); 625 dev->kcov_handle = 0; 626err_mm: 627 return err; 628} 629EXPORT_SYMBOL_GPL(vhost_dev_set_owner); 630 631static struct vhost_iotlb *iotlb_alloc(void) 632{ 633 return vhost_iotlb_alloc(max_iotlb_entries, 634 VHOST_IOTLB_FLAG_RETIRE); 635} 636 637struct vhost_iotlb *vhost_dev_reset_owner_prepare(void) 638{ 639 return iotlb_alloc(); 640} 641EXPORT_SYMBOL_GPL(vhost_dev_reset_owner_prepare); 642 643/* Caller should have device mutex */ 644void vhost_dev_reset_owner(struct vhost_dev *dev, struct vhost_iotlb *umem) 645{ 646 int i; 647 648 vhost_dev_cleanup(dev); 649 650 dev->umem = umem; 651 /* We don't need VQ locks below since vhost_dev_cleanup makes sure 652 * VQs aren't running. 653 */ 654 for (i = 0; i < dev->nvqs; ++i) 655 dev->vqs[i]->umem = umem; 656} 657EXPORT_SYMBOL_GPL(vhost_dev_reset_owner); 658 659void vhost_dev_stop(struct vhost_dev *dev) 660{ 661 int i; 662 663 for (i = 0; i < dev->nvqs; ++i) { 664 if (dev->vqs[i]->kick && dev->vqs[i]->handle_kick) { 665 vhost_poll_stop(&dev->vqs[i]->poll); 666 vhost_poll_flush(&dev->vqs[i]->poll); 667 } 668 } 669} 670EXPORT_SYMBOL_GPL(vhost_dev_stop); 671 672void vhost_clear_msg(struct vhost_dev *dev) 673{ 674 struct vhost_msg_node *node, *n; 675 676 spin_lock(&dev->iotlb_lock); 677 678 list_for_each_entry_safe(node, n, &dev->read_list, node) { 679 list_del(&node->node); 680 kfree(node); 681 } 682 683 list_for_each_entry_safe(node, n, &dev->pending_list, node) { 684 list_del(&node->node); 685 kfree(node); 686 } 687 688 spin_unlock(&dev->iotlb_lock); 689} 690EXPORT_SYMBOL_GPL(vhost_clear_msg); 691 692void vhost_dev_cleanup(struct vhost_dev *dev) 693{ 694 int i; 695 696 for (i = 0; i < dev->nvqs; ++i) { 697 if (dev->vqs[i]->error_ctx) 698 eventfd_ctx_put(dev->vqs[i]->error_ctx); 699 if (dev->vqs[i]->kick) 700 fput(dev->vqs[i]->kick); 701 if (dev->vqs[i]->call_ctx.ctx) 702 eventfd_ctx_put(dev->vqs[i]->call_ctx.ctx); 703 vhost_vq_reset(dev, dev->vqs[i]); 704 } 705 vhost_dev_free_iovecs(dev); 706 if (dev->log_ctx) 707 eventfd_ctx_put(dev->log_ctx); 708 dev->log_ctx = NULL; 709 /* No one will access memory at this point */ 710 vhost_iotlb_free(dev->umem); 711 dev->umem = NULL; 712 vhost_iotlb_free(dev->iotlb); 713 dev->iotlb = NULL; 714 vhost_clear_msg(dev); 715 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM); 716 WARN_ON(!llist_empty(&dev->work_list)); 717 if (dev->worker) { 718 kthread_stop(dev->worker); 719 dev->worker = NULL; 720 dev->kcov_handle = 0; 721 } 722 vhost_detach_mm(dev); 723} 724EXPORT_SYMBOL_GPL(vhost_dev_cleanup); 725 726static bool log_access_ok(void __user *log_base, u64 addr, unsigned long sz) 727{ 728 u64 a = addr / VHOST_PAGE_SIZE / 8; 729 730 /* Make sure 64 bit math will not overflow. */ 731 if (a > ULONG_MAX - (unsigned long)log_base || 732 a + (unsigned long)log_base > ULONG_MAX) 733 return false; 734 735 return access_ok(log_base + a, 736 (sz + VHOST_PAGE_SIZE * 8 - 1) / VHOST_PAGE_SIZE / 8); 737} 738 739/* Make sure 64 bit math will not overflow. */ 740static bool vhost_overflow(u64 uaddr, u64 size) 741{ 742 if (uaddr > ULONG_MAX || size > ULONG_MAX) 743 return true; 744 745 if (!size) 746 return false; 747 748 return uaddr > ULONG_MAX - size + 1; 749} 750 751/* Caller should have vq mutex and device mutex. */ 752static bool vq_memory_access_ok(void __user *log_base, struct vhost_iotlb *umem, 753 int log_all) 754{ 755 struct vhost_iotlb_map *map; 756 757 if (!umem) 758 return false; 759 760 list_for_each_entry(map, &umem->list, link) { 761 unsigned long a = map->addr; 762 763 if (vhost_overflow(map->addr, map->size)) 764 return false; 765 766 767 if (!access_ok((void __user *)a, map->size)) 768 return false; 769 else if (log_all && !log_access_ok(log_base, 770 map->start, 771 map->size)) 772 return false; 773 } 774 return true; 775} 776 777static inline void __user *vhost_vq_meta_fetch(struct vhost_virtqueue *vq, 778 u64 addr, unsigned int size, 779 int type) 780{ 781 const struct vhost_iotlb_map *map = vq->meta_iotlb[type]; 782 783 if (!map) 784 return NULL; 785 786 return (void __user *)(uintptr_t)(map->addr + addr - map->start); 787} 788 789/* Can we switch to this memory table? */ 790/* Caller should have device mutex but not vq mutex */ 791static bool memory_access_ok(struct vhost_dev *d, struct vhost_iotlb *umem, 792 int log_all) 793{ 794 int i; 795 796 for (i = 0; i < d->nvqs; ++i) { 797 bool ok; 798 bool log; 799 800 mutex_lock(&d->vqs[i]->mutex); 801 log = log_all || vhost_has_feature(d->vqs[i], VHOST_F_LOG_ALL); 802 /* If ring is inactive, will check when it's enabled. */ 803 if (d->vqs[i]->private_data) 804 ok = vq_memory_access_ok(d->vqs[i]->log_base, 805 umem, log); 806 else 807 ok = true; 808 mutex_unlock(&d->vqs[i]->mutex); 809 if (!ok) 810 return false; 811 } 812 return true; 813} 814 815static int translate_desc(struct vhost_virtqueue *vq, u64 addr, u32 len, 816 struct iovec iov[], int iov_size, int access); 817 818static int vhost_copy_to_user(struct vhost_virtqueue *vq, void __user *to, 819 const void *from, unsigned size) 820{ 821 int ret; 822 823 if (!vq->iotlb) 824 return __copy_to_user(to, from, size); 825 else { 826 /* This function should be called after iotlb 827 * prefetch, which means we're sure that all vq 828 * could be access through iotlb. So -EAGAIN should 829 * not happen in this case. 830 */ 831 struct iov_iter t; 832 void __user *uaddr = vhost_vq_meta_fetch(vq, 833 (u64)(uintptr_t)to, size, 834 VHOST_ADDR_USED); 835 836 if (uaddr) 837 return __copy_to_user(uaddr, from, size); 838 839 ret = translate_desc(vq, (u64)(uintptr_t)to, size, vq->iotlb_iov, 840 ARRAY_SIZE(vq->iotlb_iov), 841 VHOST_ACCESS_WO); 842 if (ret < 0) 843 goto out; 844 iov_iter_init(&t, WRITE, vq->iotlb_iov, ret, size); 845 ret = copy_to_iter(from, size, &t); 846 if (ret == size) 847 ret = 0; 848 } 849out: 850 return ret; 851} 852 853static int vhost_copy_from_user(struct vhost_virtqueue *vq, void *to, 854 void __user *from, unsigned size) 855{ 856 int ret; 857 858 if (!vq->iotlb) 859 return __copy_from_user(to, from, size); 860 else { 861 /* This function should be called after iotlb 862 * prefetch, which means we're sure that vq 863 * could be access through iotlb. So -EAGAIN should 864 * not happen in this case. 865 */ 866 void __user *uaddr = vhost_vq_meta_fetch(vq, 867 (u64)(uintptr_t)from, size, 868 VHOST_ADDR_DESC); 869 struct iov_iter f; 870 871 if (uaddr) 872 return __copy_from_user(to, uaddr, size); 873 874 ret = translate_desc(vq, (u64)(uintptr_t)from, size, vq->iotlb_iov, 875 ARRAY_SIZE(vq->iotlb_iov), 876 VHOST_ACCESS_RO); 877 if (ret < 0) { 878 vq_err(vq, "IOTLB translation failure: uaddr " 879 "%p size 0x%llx\n", from, 880 (unsigned long long) size); 881 goto out; 882 } 883 iov_iter_init(&f, READ, vq->iotlb_iov, ret, size); 884 ret = copy_from_iter(to, size, &f); 885 if (ret == size) 886 ret = 0; 887 } 888 889out: 890 return ret; 891} 892 893static void __user *__vhost_get_user_slow(struct vhost_virtqueue *vq, 894 void __user *addr, unsigned int size, 895 int type) 896{ 897 int ret; 898 899 ret = translate_desc(vq, (u64)(uintptr_t)addr, size, vq->iotlb_iov, 900 ARRAY_SIZE(vq->iotlb_iov), 901 VHOST_ACCESS_RO); 902 if (ret < 0) { 903 vq_err(vq, "IOTLB translation failure: uaddr " 904 "%p size 0x%llx\n", addr, 905 (unsigned long long) size); 906 return NULL; 907 } 908 909 if (ret != 1 || vq->iotlb_iov[0].iov_len != size) { 910 vq_err(vq, "Non atomic userspace memory access: uaddr " 911 "%p size 0x%llx\n", addr, 912 (unsigned long long) size); 913 return NULL; 914 } 915 916 return vq->iotlb_iov[0].iov_base; 917} 918 919/* This function should be called after iotlb 920 * prefetch, which means we're sure that vq 921 * could be access through iotlb. So -EAGAIN should 922 * not happen in this case. 923 */ 924static inline void __user *__vhost_get_user(struct vhost_virtqueue *vq, 925 void __user *addr, unsigned int size, 926 int type) 927{ 928 void __user *uaddr = vhost_vq_meta_fetch(vq, 929 (u64)(uintptr_t)addr, size, type); 930 if (uaddr) 931 return uaddr; 932 933 return __vhost_get_user_slow(vq, addr, size, type); 934} 935 936#define vhost_put_user(vq, x, ptr) \ 937({ \ 938 int ret; \ 939 if (!vq->iotlb) { \ 940 ret = __put_user(x, ptr); \ 941 } else { \ 942 __typeof__(ptr) to = \ 943 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \ 944 sizeof(*ptr), VHOST_ADDR_USED); \ 945 if (to != NULL) \ 946 ret = __put_user(x, to); \ 947 else \ 948 ret = -EFAULT; \ 949 } \ 950 ret; \ 951}) 952 953static inline int vhost_put_avail_event(struct vhost_virtqueue *vq) 954{ 955 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->avail_idx), 956 vhost_avail_event(vq)); 957} 958 959static inline int vhost_put_used(struct vhost_virtqueue *vq, 960 struct vring_used_elem *head, int idx, 961 int count) 962{ 963 return vhost_copy_to_user(vq, vq->used->ring + idx, head, 964 count * sizeof(*head)); 965} 966 967static inline int vhost_put_used_flags(struct vhost_virtqueue *vq) 968 969{ 970 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->used_flags), 971 &vq->used->flags); 972} 973 974static inline int vhost_put_used_idx(struct vhost_virtqueue *vq) 975 976{ 977 return vhost_put_user(vq, cpu_to_vhost16(vq, vq->last_used_idx), 978 &vq->used->idx); 979} 980 981#define vhost_get_user(vq, x, ptr, type) \ 982({ \ 983 int ret; \ 984 if (!vq->iotlb) { \ 985 ret = __get_user(x, ptr); \ 986 } else { \ 987 __typeof__(ptr) from = \ 988 (__typeof__(ptr)) __vhost_get_user(vq, ptr, \ 989 sizeof(*ptr), \ 990 type); \ 991 if (from != NULL) \ 992 ret = __get_user(x, from); \ 993 else \ 994 ret = -EFAULT; \ 995 } \ 996 ret; \ 997}) 998 999#define vhost_get_avail(vq, x, ptr) \ 1000 vhost_get_user(vq, x, ptr, VHOST_ADDR_AVAIL) 1001 1002#define vhost_get_used(vq, x, ptr) \ 1003 vhost_get_user(vq, x, ptr, VHOST_ADDR_USED) 1004 1005static void vhost_dev_lock_vqs(struct vhost_dev *d) 1006{ 1007 int i = 0; 1008 for (i = 0; i < d->nvqs; ++i) 1009 mutex_lock_nested(&d->vqs[i]->mutex, i); 1010} 1011 1012static void vhost_dev_unlock_vqs(struct vhost_dev *d) 1013{ 1014 int i = 0; 1015 for (i = 0; i < d->nvqs; ++i) 1016 mutex_unlock(&d->vqs[i]->mutex); 1017} 1018 1019static inline int vhost_get_avail_idx(struct vhost_virtqueue *vq, 1020 __virtio16 *idx) 1021{ 1022 return vhost_get_avail(vq, *idx, &vq->avail->idx); 1023} 1024 1025static inline int vhost_get_avail_head(struct vhost_virtqueue *vq, 1026 __virtio16 *head, int idx) 1027{ 1028 return vhost_get_avail(vq, *head, 1029 &vq->avail->ring[idx & (vq->num - 1)]); 1030} 1031 1032static inline int vhost_get_avail_flags(struct vhost_virtqueue *vq, 1033 __virtio16 *flags) 1034{ 1035 return vhost_get_avail(vq, *flags, &vq->avail->flags); 1036} 1037 1038static inline int vhost_get_used_event(struct vhost_virtqueue *vq, 1039 __virtio16 *event) 1040{ 1041 return vhost_get_avail(vq, *event, vhost_used_event(vq)); 1042} 1043 1044static inline int vhost_get_used_idx(struct vhost_virtqueue *vq, 1045 __virtio16 *idx) 1046{ 1047 return vhost_get_used(vq, *idx, &vq->used->idx); 1048} 1049 1050static inline int vhost_get_desc(struct vhost_virtqueue *vq, 1051 struct vring_desc *desc, int idx) 1052{ 1053 return vhost_copy_from_user(vq, desc, vq->desc + idx, sizeof(*desc)); 1054} 1055 1056static void vhost_iotlb_notify_vq(struct vhost_dev *d, 1057 struct vhost_iotlb_msg *msg) 1058{ 1059 struct vhost_msg_node *node, *n; 1060 1061 spin_lock(&d->iotlb_lock); 1062 1063 list_for_each_entry_safe(node, n, &d->pending_list, node) { 1064 struct vhost_iotlb_msg *vq_msg = &node->msg.iotlb; 1065 if (msg->iova <= vq_msg->iova && 1066 msg->iova + msg->size - 1 >= vq_msg->iova && 1067 vq_msg->type == VHOST_IOTLB_MISS) { 1068 vhost_poll_queue(&node->vq->poll); 1069 list_del(&node->node); 1070 kfree(node); 1071 } 1072 } 1073 1074 spin_unlock(&d->iotlb_lock); 1075} 1076 1077static bool umem_access_ok(u64 uaddr, u64 size, int access) 1078{ 1079 unsigned long a = uaddr; 1080 1081 /* Make sure 64 bit math will not overflow. */ 1082 if (vhost_overflow(uaddr, size)) 1083 return false; 1084 1085 if ((access & VHOST_ACCESS_RO) && 1086 !access_ok((void __user *)a, size)) 1087 return false; 1088 if ((access & VHOST_ACCESS_WO) && 1089 !access_ok((void __user *)a, size)) 1090 return false; 1091 return true; 1092} 1093 1094static int vhost_process_iotlb_msg(struct vhost_dev *dev, 1095 struct vhost_iotlb_msg *msg) 1096{ 1097 int ret = 0; 1098 1099 mutex_lock(&dev->mutex); 1100 vhost_dev_lock_vqs(dev); 1101 switch (msg->type) { 1102 case VHOST_IOTLB_UPDATE: 1103 if (!dev->iotlb) { 1104 ret = -EFAULT; 1105 break; 1106 } 1107 if (!umem_access_ok(msg->uaddr, msg->size, msg->perm)) { 1108 ret = -EFAULT; 1109 break; 1110 } 1111 vhost_vq_meta_reset(dev); 1112 if (vhost_iotlb_add_range(dev->iotlb, msg->iova, 1113 msg->iova + msg->size - 1, 1114 msg->uaddr, msg->perm)) { 1115 ret = -ENOMEM; 1116 break; 1117 } 1118 vhost_iotlb_notify_vq(dev, msg); 1119 break; 1120 case VHOST_IOTLB_INVALIDATE: 1121 if (!dev->iotlb) { 1122 ret = -EFAULT; 1123 break; 1124 } 1125 vhost_vq_meta_reset(dev); 1126 vhost_iotlb_del_range(dev->iotlb, msg->iova, 1127 msg->iova + msg->size - 1); 1128 break; 1129 default: 1130 ret = -EINVAL; 1131 break; 1132 } 1133 1134 vhost_dev_unlock_vqs(dev); 1135 mutex_unlock(&dev->mutex); 1136 1137 return ret; 1138} 1139ssize_t vhost_chr_write_iter(struct vhost_dev *dev, 1140 struct iov_iter *from) 1141{ 1142 struct vhost_iotlb_msg msg; 1143 size_t offset; 1144 int type, ret; 1145 1146 ret = copy_from_iter(&type, sizeof(type), from); 1147 if (ret != sizeof(type)) { 1148 ret = -EINVAL; 1149 goto done; 1150 } 1151 1152 switch (type) { 1153 case VHOST_IOTLB_MSG: 1154 /* There maybe a hole after type for V1 message type, 1155 * so skip it here. 1156 */ 1157 offset = offsetof(struct vhost_msg, iotlb) - sizeof(int); 1158 break; 1159 case VHOST_IOTLB_MSG_V2: 1160 offset = sizeof(__u32); 1161 break; 1162 default: 1163 ret = -EINVAL; 1164 goto done; 1165 } 1166 1167 iov_iter_advance(from, offset); 1168 ret = copy_from_iter(&msg, sizeof(msg), from); 1169 if (ret != sizeof(msg)) { 1170 ret = -EINVAL; 1171 goto done; 1172 } 1173 1174 if (dev->msg_handler) 1175 ret = dev->msg_handler(dev, &msg); 1176 else 1177 ret = vhost_process_iotlb_msg(dev, &msg); 1178 if (ret) { 1179 ret = -EFAULT; 1180 goto done; 1181 } 1182 1183 ret = (type == VHOST_IOTLB_MSG) ? sizeof(struct vhost_msg) : 1184 sizeof(struct vhost_msg_v2); 1185done: 1186 return ret; 1187} 1188EXPORT_SYMBOL(vhost_chr_write_iter); 1189 1190__poll_t vhost_chr_poll(struct file *file, struct vhost_dev *dev, 1191 poll_table *wait) 1192{ 1193 __poll_t mask = 0; 1194 1195 poll_wait(file, &dev->wait, wait); 1196 1197 if (!list_empty(&dev->read_list)) 1198 mask |= EPOLLIN | EPOLLRDNORM; 1199 1200 return mask; 1201} 1202EXPORT_SYMBOL(vhost_chr_poll); 1203 1204ssize_t vhost_chr_read_iter(struct vhost_dev *dev, struct iov_iter *to, 1205 int noblock) 1206{ 1207 DEFINE_WAIT(wait); 1208 struct vhost_msg_node *node; 1209 ssize_t ret = 0; 1210 unsigned size = sizeof(struct vhost_msg); 1211 1212 if (iov_iter_count(to) < size) 1213 return 0; 1214 1215 while (1) { 1216 if (!noblock) 1217 prepare_to_wait(&dev->wait, &wait, 1218 TASK_INTERRUPTIBLE); 1219 1220 node = vhost_dequeue_msg(dev, &dev->read_list); 1221 if (node) 1222 break; 1223 if (noblock) { 1224 ret = -EAGAIN; 1225 break; 1226 } 1227 if (signal_pending(current)) { 1228 ret = -ERESTARTSYS; 1229 break; 1230 } 1231 if (!dev->iotlb) { 1232 ret = -EBADFD; 1233 break; 1234 } 1235 1236 schedule(); 1237 } 1238 1239 if (!noblock) 1240 finish_wait(&dev->wait, &wait); 1241 1242 if (node) { 1243 struct vhost_iotlb_msg *msg; 1244 void *start = &node->msg; 1245 1246 switch (node->msg.type) { 1247 case VHOST_IOTLB_MSG: 1248 size = sizeof(node->msg); 1249 msg = &node->msg.iotlb; 1250 break; 1251 case VHOST_IOTLB_MSG_V2: 1252 size = sizeof(node->msg_v2); 1253 msg = &node->msg_v2.iotlb; 1254 break; 1255 default: 1256 BUG(); 1257 break; 1258 } 1259 1260 ret = copy_to_iter(start, size, to); 1261 if (ret != size || msg->type != VHOST_IOTLB_MISS) { 1262 kfree(node); 1263 return ret; 1264 } 1265 vhost_enqueue_msg(dev, &dev->pending_list, node); 1266 } 1267 1268 return ret; 1269} 1270EXPORT_SYMBOL_GPL(vhost_chr_read_iter); 1271 1272static int vhost_iotlb_miss(struct vhost_virtqueue *vq, u64 iova, int access) 1273{ 1274 struct vhost_dev *dev = vq->dev; 1275 struct vhost_msg_node *node; 1276 struct vhost_iotlb_msg *msg; 1277 bool v2 = vhost_backend_has_feature(vq, VHOST_BACKEND_F_IOTLB_MSG_V2); 1278 1279 node = vhost_new_msg(vq, v2 ? VHOST_IOTLB_MSG_V2 : VHOST_IOTLB_MSG); 1280 if (!node) 1281 return -ENOMEM; 1282 1283 if (v2) { 1284 node->msg_v2.type = VHOST_IOTLB_MSG_V2; 1285 msg = &node->msg_v2.iotlb; 1286 } else { 1287 msg = &node->msg.iotlb; 1288 } 1289 1290 msg->type = VHOST_IOTLB_MISS; 1291 msg->iova = iova; 1292 msg->perm = access; 1293 1294 vhost_enqueue_msg(dev, &dev->read_list, node); 1295 1296 return 0; 1297} 1298 1299static bool vq_access_ok(struct vhost_virtqueue *vq, unsigned int num, 1300 vring_desc_t __user *desc, 1301 vring_avail_t __user *avail, 1302 vring_used_t __user *used) 1303 1304{ 1305 /* If an IOTLB device is present, the vring addresses are 1306 * GIOVAs. Access validation occurs at prefetch time. */ 1307 if (vq->iotlb) 1308 return true; 1309 1310 return access_ok(desc, vhost_get_desc_size(vq, num)) && 1311 access_ok(avail, vhost_get_avail_size(vq, num)) && 1312 access_ok(used, vhost_get_used_size(vq, num)); 1313} 1314 1315static void vhost_vq_meta_update(struct vhost_virtqueue *vq, 1316 const struct vhost_iotlb_map *map, 1317 int type) 1318{ 1319 int access = (type == VHOST_ADDR_USED) ? 1320 VHOST_ACCESS_WO : VHOST_ACCESS_RO; 1321 1322 if (likely(map->perm & access)) 1323 vq->meta_iotlb[type] = map; 1324} 1325 1326static bool iotlb_access_ok(struct vhost_virtqueue *vq, 1327 int access, u64 addr, u64 len, int type) 1328{ 1329 const struct vhost_iotlb_map *map; 1330 struct vhost_iotlb *umem = vq->iotlb; 1331 u64 s = 0, size, orig_addr = addr, last = addr + len - 1; 1332 1333 if (vhost_vq_meta_fetch(vq, addr, len, type)) 1334 return true; 1335 1336 while (len > s) { 1337 map = vhost_iotlb_itree_first(umem, addr, last); 1338 if (map == NULL || map->start > addr) { 1339 vhost_iotlb_miss(vq, addr, access); 1340 return false; 1341 } else if (!(map->perm & access)) { 1342 /* Report the possible access violation by 1343 * request another translation from userspace. 1344 */ 1345 return false; 1346 } 1347 1348 size = map->size - addr + map->start; 1349 1350 if (orig_addr == addr && size >= len) 1351 vhost_vq_meta_update(vq, map, type); 1352 1353 s += size; 1354 addr += size; 1355 } 1356 1357 return true; 1358} 1359 1360int vq_meta_prefetch(struct vhost_virtqueue *vq) 1361{ 1362 unsigned int num = vq->num; 1363 1364 if (!vq->iotlb) 1365 return 1; 1366 1367 return iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->desc, 1368 vhost_get_desc_size(vq, num), VHOST_ADDR_DESC) && 1369 iotlb_access_ok(vq, VHOST_MAP_RO, (u64)(uintptr_t)vq->avail, 1370 vhost_get_avail_size(vq, num), 1371 VHOST_ADDR_AVAIL) && 1372 iotlb_access_ok(vq, VHOST_MAP_WO, (u64)(uintptr_t)vq->used, 1373 vhost_get_used_size(vq, num), VHOST_ADDR_USED); 1374} 1375EXPORT_SYMBOL_GPL(vq_meta_prefetch); 1376 1377/* Can we log writes? */ 1378/* Caller should have device mutex but not vq mutex */ 1379bool vhost_log_access_ok(struct vhost_dev *dev) 1380{ 1381 return memory_access_ok(dev, dev->umem, 1); 1382} 1383EXPORT_SYMBOL_GPL(vhost_log_access_ok); 1384 1385static bool vq_log_used_access_ok(struct vhost_virtqueue *vq, 1386 void __user *log_base, 1387 bool log_used, 1388 u64 log_addr) 1389{ 1390 /* If an IOTLB device is present, log_addr is a GIOVA that 1391 * will never be logged by log_used(). */ 1392 if (vq->iotlb) 1393 return true; 1394 1395 return !log_used || log_access_ok(log_base, log_addr, 1396 vhost_get_used_size(vq, vq->num)); 1397} 1398 1399/* Verify access for write logging. */ 1400/* Caller should have vq mutex and device mutex */ 1401static bool vq_log_access_ok(struct vhost_virtqueue *vq, 1402 void __user *log_base) 1403{ 1404 return vq_memory_access_ok(log_base, vq->umem, 1405 vhost_has_feature(vq, VHOST_F_LOG_ALL)) && 1406 vq_log_used_access_ok(vq, log_base, vq->log_used, vq->log_addr); 1407} 1408 1409/* Can we start vq? */ 1410/* Caller should have vq mutex and device mutex */ 1411bool vhost_vq_access_ok(struct vhost_virtqueue *vq) 1412{ 1413 if (!vq_log_access_ok(vq, vq->log_base)) 1414 return false; 1415 1416 return vq_access_ok(vq, vq->num, vq->desc, vq->avail, vq->used); 1417} 1418EXPORT_SYMBOL_GPL(vhost_vq_access_ok); 1419 1420static long vhost_set_memory(struct vhost_dev *d, struct vhost_memory __user *m) 1421{ 1422 struct vhost_memory mem, *newmem; 1423 struct vhost_memory_region *region; 1424 struct vhost_iotlb *newumem, *oldumem; 1425 unsigned long size = offsetof(struct vhost_memory, regions); 1426 int i; 1427 1428 if (copy_from_user(&mem, m, size)) 1429 return -EFAULT; 1430 if (mem.padding) 1431 return -EOPNOTSUPP; 1432 if (mem.nregions > max_mem_regions) 1433 return -E2BIG; 1434 newmem = kvzalloc(struct_size(newmem, regions, mem.nregions), 1435 GFP_KERNEL); 1436 if (!newmem) 1437 return -ENOMEM; 1438 1439 memcpy(newmem, &mem, size); 1440 if (copy_from_user(newmem->regions, m->regions, 1441 flex_array_size(newmem, regions, mem.nregions))) { 1442 kvfree(newmem); 1443 return -EFAULT; 1444 } 1445 1446 newumem = iotlb_alloc(); 1447 if (!newumem) { 1448 kvfree(newmem); 1449 return -ENOMEM; 1450 } 1451 1452 for (region = newmem->regions; 1453 region < newmem->regions + mem.nregions; 1454 region++) { 1455 if (vhost_iotlb_add_range(newumem, 1456 region->guest_phys_addr, 1457 region->guest_phys_addr + 1458 region->memory_size - 1, 1459 region->userspace_addr, 1460 VHOST_MAP_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_iotlb_free(oldumem); 1479 return 0; 1480 1481err: 1482 vhost_iotlb_free(newumem); 1483 kvfree(newmem); 1484 return -EFAULT; 1485} 1486 1487static 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 1508static 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 (!vq_log_used_access_ok(vq, vq->log_base, 1546 a.flags & (0x1 << VHOST_VRING_F_LOG), 1547 a.log_guest_addr)) 1548 return -EINVAL; 1549 } 1550 1551 vq->log_used = !!(a.flags & (0x1 << VHOST_VRING_F_LOG)); 1552 vq->desc = (void __user *)(unsigned long)a.desc_user_addr; 1553 vq->avail = (void __user *)(unsigned long)a.avail_user_addr; 1554 vq->log_addr = a.log_guest_addr; 1555 vq->used = (void __user *)(unsigned long)a.used_user_addr; 1556 1557 return 0; 1558} 1559 1560static long vhost_vring_set_num_addr(struct vhost_dev *d, 1561 struct vhost_virtqueue *vq, 1562 unsigned int ioctl, 1563 void __user *argp) 1564{ 1565 long r; 1566 1567 mutex_lock(&vq->mutex); 1568 1569 switch (ioctl) { 1570 case VHOST_SET_VRING_NUM: 1571 r = vhost_vring_set_num(d, vq, argp); 1572 break; 1573 case VHOST_SET_VRING_ADDR: 1574 r = vhost_vring_set_addr(d, vq, argp); 1575 break; 1576 default: 1577 BUG(); 1578 } 1579 1580 mutex_unlock(&vq->mutex); 1581 1582 return r; 1583} 1584long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *argp) 1585{ 1586 struct file *eventfp, *filep = NULL; 1587 bool pollstart = false, pollstop = false; 1588 struct eventfd_ctx *ctx = NULL; 1589 u32 __user *idxp = argp; 1590 struct vhost_virtqueue *vq; 1591 struct vhost_vring_state s; 1592 struct vhost_vring_file f; 1593 u32 idx; 1594 long r; 1595 1596 r = get_user(idx, idxp); 1597 if (r < 0) 1598 return r; 1599 if (idx >= d->nvqs) 1600 return -ENOBUFS; 1601 1602 idx = array_index_nospec(idx, d->nvqs); 1603 vq = d->vqs[idx]; 1604 1605 if (ioctl == VHOST_SET_VRING_NUM || 1606 ioctl == VHOST_SET_VRING_ADDR) { 1607 return vhost_vring_set_num_addr(d, vq, ioctl, argp); 1608 } 1609 1610 mutex_lock(&vq->mutex); 1611 1612 switch (ioctl) { 1613 case VHOST_SET_VRING_BASE: 1614 /* Moving base with an active backend? 1615 * You don't want to do that. */ 1616 if (vq->private_data) { 1617 r = -EBUSY; 1618 break; 1619 } 1620 if (copy_from_user(&s, argp, sizeof s)) { 1621 r = -EFAULT; 1622 break; 1623 } 1624 if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) { 1625 vq->last_avail_idx = s.num & 0xffff; 1626 vq->last_used_idx = (s.num >> 16) & 0xffff; 1627 } else { 1628 if (s.num > 0xffff) { 1629 r = -EINVAL; 1630 break; 1631 } 1632 vq->last_avail_idx = s.num; 1633 } 1634 /* Forget the cached index value. */ 1635 vq->avail_idx = vq->last_avail_idx; 1636 break; 1637 case VHOST_GET_VRING_BASE: 1638 s.index = idx; 1639 if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) 1640 s.num = (u32)vq->last_avail_idx | ((u32)vq->last_used_idx << 16); 1641 else 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_poll_flush(&vq->poll); 1725 return r; 1726} 1727EXPORT_SYMBOL_GPL(vhost_vring_ioctl); 1728 1729int vhost_init_device_iotlb(struct vhost_dev *d, bool enabled) 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} 1754EXPORT_SYMBOL_GPL(vhost_init_device_iotlb); 1755 1756/* Caller must have device mutex */ 1757long 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 } 1823done: 1824 return r; 1825} 1826EXPORT_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/x86/exception-tables.rst. 1831 */ 1832static 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 1851static 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 1877static 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 1916static 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 1939int 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} 1973EXPORT_SYMBOL_GPL(vhost_log_write); 1974 1975static 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 1993static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event) 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 2011int 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 2040err: 2041 vq->is_le = is_le; 2042 return r; 2043} 2044EXPORT_SYMBOL_GPL(vhost_vq_init_access); 2045 2046static 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. */ 2094static 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 2107static 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, READ, 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. */ 2208int 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} 2347EXPORT_SYMBOL_GPL(vhost_get_vq_desc); 2348 2349/* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */ 2350void vhost_discard_vq_desc(struct vhost_virtqueue *vq, int n) 2351{ 2352 vq->last_avail_idx -= n; 2353} 2354EXPORT_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. */ 2358int 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} 2367EXPORT_SYMBOL_GPL(vhost_add_used); 2368 2369static 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. */ 2403int 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} 2436EXPORT_SYMBOL_GPL(vhost_add_used_n); 2437 2438static 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. */ 2476void 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} 2482EXPORT_SYMBOL_GPL(vhost_signal); 2483 2484/* And here's the combo meal deal. Supersize me! */ 2485void 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} 2492EXPORT_SYMBOL_GPL(vhost_add_used_and_signal); 2493 2494/* multi-buffer version of vhost_add_used_and_signal */ 2495void 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} 2502EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n); 2503 2504/* return true if we're sure that avaiable ring is empty */ 2505bool 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} 2520EXPORT_SYMBOL_GPL(vhost_vq_avail_empty); 2521 2522/* OK, now we need to know about added descriptors. */ 2523bool 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} 2558EXPORT_SYMBOL_GPL(vhost_enable_notify); 2559 2560/* We don't need to be notified again. */ 2561void 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 disable notification at %p: %d\n", 2572 &vq->used->flags, r); 2573 } 2574} 2575EXPORT_SYMBOL_GPL(vhost_disable_notify); 2576 2577/* Create a new message. */ 2578struct vhost_msg_node *vhost_new_msg(struct vhost_virtqueue *vq, int type) 2579{ 2580 /* Make sure all padding within the structure is initialized. */ 2581 struct vhost_msg_node *node = kzalloc(sizeof(*node), GFP_KERNEL); 2582 if (!node) 2583 return NULL; 2584 2585 node->vq = vq; 2586 node->msg.type = type; 2587 return node; 2588} 2589EXPORT_SYMBOL_GPL(vhost_new_msg); 2590 2591void vhost_enqueue_msg(struct vhost_dev *dev, struct list_head *head, 2592 struct vhost_msg_node *node) 2593{ 2594 spin_lock(&dev->iotlb_lock); 2595 list_add_tail(&node->node, head); 2596 spin_unlock(&dev->iotlb_lock); 2597 2598 wake_up_interruptible_poll(&dev->wait, EPOLLIN | EPOLLRDNORM); 2599} 2600EXPORT_SYMBOL_GPL(vhost_enqueue_msg); 2601 2602struct vhost_msg_node *vhost_dequeue_msg(struct vhost_dev *dev, 2603 struct list_head *head) 2604{ 2605 struct vhost_msg_node *node = NULL; 2606 2607 spin_lock(&dev->iotlb_lock); 2608 if (!list_empty(head)) { 2609 node = list_first_entry(head, struct vhost_msg_node, 2610 node); 2611 list_del(&node->node); 2612 } 2613 spin_unlock(&dev->iotlb_lock); 2614 2615 return node; 2616} 2617EXPORT_SYMBOL_GPL(vhost_dequeue_msg); 2618 2619void vhost_set_backend_features(struct vhost_dev *dev, u64 features) 2620{ 2621 struct vhost_virtqueue *vq; 2622 int i; 2623 2624 mutex_lock(&dev->mutex); 2625 for (i = 0; i < dev->nvqs; ++i) { 2626 vq = dev->vqs[i]; 2627 mutex_lock(&vq->mutex); 2628 vq->acked_backend_features = features; 2629 mutex_unlock(&vq->mutex); 2630 } 2631 mutex_unlock(&dev->mutex); 2632} 2633EXPORT_SYMBOL_GPL(vhost_set_backend_features); 2634 2635static int __init vhost_init(void) 2636{ 2637 return 0; 2638} 2639 2640static void __exit vhost_exit(void) 2641{ 2642} 2643 2644module_init(vhost_init); 2645module_exit(vhost_exit); 2646 2647MODULE_VERSION("0.0.1"); 2648MODULE_LICENSE("GPL v2"); 2649MODULE_AUTHOR("Michael S. Tsirkin"); 2650MODULE_DESCRIPTION("Host kernel accelerator for virtio"); 2651