1 /* 2 * VFIO: IOMMU DMA mapping support for Type1 IOMMU 3 * 4 * Copyright (C) 2012 Red Hat, Inc. All rights reserved. 5 * Author: Alex Williamson <alex.williamson@redhat.com> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License version 2 as 9 * published by the Free Software Foundation. 10 * 11 * Derived from original vfio: 12 * Copyright 2010 Cisco Systems, Inc. All rights reserved. 13 * Author: Tom Lyon, pugs@cisco.com 14 * 15 * We arbitrarily define a Type1 IOMMU as one matching the below code. 16 * It could be called the x86 IOMMU as it's designed for AMD-Vi & Intel 17 * VT-d, but that makes it harder to re-use as theoretically anyone 18 * implementing a similar IOMMU could make use of this. We expect the 19 * IOMMU to support the IOMMU API and have few to no restrictions around 20 * the IOVA range that can be mapped. The Type1 IOMMU is currently 21 * optimized for relatively static mappings of a userspace process with 22 * userpsace pages pinned into memory. We also assume devices and IOMMU 23 * domains are PCI based as the IOMMU API is still centered around a 24 * device/bus interface rather than a group interface. 25 */ 26 27 #include <linux/compat.h> 28 #include <linux/device.h> 29 #include <linux/fs.h> 30 #include <linux/iommu.h> 31 #include <linux/module.h> 32 #include <linux/mm.h> 33 #include <linux/rbtree.h> 34 #include <linux/sched/signal.h> 35 #include <linux/sched/mm.h> 36 #include <linux/slab.h> 37 #include <linux/uaccess.h> 38 #include <linux/vfio.h> 39 #include <linux/workqueue.h> 40 #include <linux/mdev.h> 41 #include <linux/notifier.h> 42 #include <linux/dma-iommu.h> 43 #include <linux/irqdomain.h> 44 45 #define DRIVER_VERSION "0.2" 46 #define DRIVER_AUTHOR "Alex Williamson <alex.williamson@redhat.com>" 47 #define DRIVER_DESC "Type1 IOMMU driver for VFIO" 48 49 static bool allow_unsafe_interrupts; 50 module_param_named(allow_unsafe_interrupts, 51 allow_unsafe_interrupts, bool, S_IRUGO | S_IWUSR); 52 MODULE_PARM_DESC(allow_unsafe_interrupts, 53 "Enable VFIO IOMMU support for on platforms without interrupt remapping support."); 54 55 static bool disable_hugepages; 56 module_param_named(disable_hugepages, 57 disable_hugepages, bool, S_IRUGO | S_IWUSR); 58 MODULE_PARM_DESC(disable_hugepages, 59 "Disable VFIO IOMMU support for IOMMU hugepages."); 60 61 struct vfio_iommu { 62 struct list_head domain_list; 63 struct vfio_domain *external_domain; /* domain for external user */ 64 struct mutex lock; 65 struct rb_root dma_list; 66 struct blocking_notifier_head notifier; 67 bool v2; 68 bool nesting; 69 }; 70 71 struct vfio_domain { 72 struct iommu_domain *domain; 73 struct list_head next; 74 struct list_head group_list; 75 int prot; /* IOMMU_CACHE */ 76 bool fgsp; /* Fine-grained super pages */ 77 }; 78 79 struct vfio_dma { 80 struct rb_node node; 81 dma_addr_t iova; /* Device address */ 82 unsigned long vaddr; /* Process virtual addr */ 83 size_t size; /* Map size (bytes) */ 84 int prot; /* IOMMU_READ/WRITE */ 85 bool iommu_mapped; 86 bool lock_cap; /* capable(CAP_IPC_LOCK) */ 87 struct task_struct *task; 88 struct rb_root pfn_list; /* Ex-user pinned pfn list */ 89 }; 90 91 struct vfio_group { 92 struct iommu_group *iommu_group; 93 struct list_head next; 94 }; 95 96 /* 97 * Guest RAM pinning working set or DMA target 98 */ 99 struct vfio_pfn { 100 struct rb_node node; 101 dma_addr_t iova; /* Device address */ 102 unsigned long pfn; /* Host pfn */ 103 atomic_t ref_count; 104 }; 105 106 struct vfio_regions { 107 struct list_head list; 108 dma_addr_t iova; 109 phys_addr_t phys; 110 size_t len; 111 }; 112 113 #define IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu) \ 114 (!list_empty(&iommu->domain_list)) 115 116 static int put_pfn(unsigned long pfn, int prot); 117 118 /* 119 * This code handles mapping and unmapping of user data buffers 120 * into DMA'ble space using the IOMMU 121 */ 122 123 static struct vfio_dma *vfio_find_dma(struct vfio_iommu *iommu, 124 dma_addr_t start, size_t size) 125 { 126 struct rb_node *node = iommu->dma_list.rb_node; 127 128 while (node) { 129 struct vfio_dma *dma = rb_entry(node, struct vfio_dma, node); 130 131 if (start + size <= dma->iova) 132 node = node->rb_left; 133 else if (start >= dma->iova + dma->size) 134 node = node->rb_right; 135 else 136 return dma; 137 } 138 139 return NULL; 140 } 141 142 static void vfio_link_dma(struct vfio_iommu *iommu, struct vfio_dma *new) 143 { 144 struct rb_node **link = &iommu->dma_list.rb_node, *parent = NULL; 145 struct vfio_dma *dma; 146 147 while (*link) { 148 parent = *link; 149 dma = rb_entry(parent, struct vfio_dma, node); 150 151 if (new->iova + new->size <= dma->iova) 152 link = &(*link)->rb_left; 153 else 154 link = &(*link)->rb_right; 155 } 156 157 rb_link_node(&new->node, parent, link); 158 rb_insert_color(&new->node, &iommu->dma_list); 159 } 160 161 static void vfio_unlink_dma(struct vfio_iommu *iommu, struct vfio_dma *old) 162 { 163 rb_erase(&old->node, &iommu->dma_list); 164 } 165 166 /* 167 * Helper Functions for host iova-pfn list 168 */ 169 static struct vfio_pfn *vfio_find_vpfn(struct vfio_dma *dma, dma_addr_t iova) 170 { 171 struct vfio_pfn *vpfn; 172 struct rb_node *node = dma->pfn_list.rb_node; 173 174 while (node) { 175 vpfn = rb_entry(node, struct vfio_pfn, node); 176 177 if (iova < vpfn->iova) 178 node = node->rb_left; 179 else if (iova > vpfn->iova) 180 node = node->rb_right; 181 else 182 return vpfn; 183 } 184 return NULL; 185 } 186 187 static void vfio_link_pfn(struct vfio_dma *dma, 188 struct vfio_pfn *new) 189 { 190 struct rb_node **link, *parent = NULL; 191 struct vfio_pfn *vpfn; 192 193 link = &dma->pfn_list.rb_node; 194 while (*link) { 195 parent = *link; 196 vpfn = rb_entry(parent, struct vfio_pfn, node); 197 198 if (new->iova < vpfn->iova) 199 link = &(*link)->rb_left; 200 else 201 link = &(*link)->rb_right; 202 } 203 204 rb_link_node(&new->node, parent, link); 205 rb_insert_color(&new->node, &dma->pfn_list); 206 } 207 208 static void vfio_unlink_pfn(struct vfio_dma *dma, struct vfio_pfn *old) 209 { 210 rb_erase(&old->node, &dma->pfn_list); 211 } 212 213 static int vfio_add_to_pfn_list(struct vfio_dma *dma, dma_addr_t iova, 214 unsigned long pfn) 215 { 216 struct vfio_pfn *vpfn; 217 218 vpfn = kzalloc(sizeof(*vpfn), GFP_KERNEL); 219 if (!vpfn) 220 return -ENOMEM; 221 222 vpfn->iova = iova; 223 vpfn->pfn = pfn; 224 atomic_set(&vpfn->ref_count, 1); 225 vfio_link_pfn(dma, vpfn); 226 return 0; 227 } 228 229 static void vfio_remove_from_pfn_list(struct vfio_dma *dma, 230 struct vfio_pfn *vpfn) 231 { 232 vfio_unlink_pfn(dma, vpfn); 233 kfree(vpfn); 234 } 235 236 static struct vfio_pfn *vfio_iova_get_vfio_pfn(struct vfio_dma *dma, 237 unsigned long iova) 238 { 239 struct vfio_pfn *vpfn = vfio_find_vpfn(dma, iova); 240 241 if (vpfn) 242 atomic_inc(&vpfn->ref_count); 243 return vpfn; 244 } 245 246 static int vfio_iova_put_vfio_pfn(struct vfio_dma *dma, struct vfio_pfn *vpfn) 247 { 248 int ret = 0; 249 250 if (atomic_dec_and_test(&vpfn->ref_count)) { 251 ret = put_pfn(vpfn->pfn, dma->prot); 252 vfio_remove_from_pfn_list(dma, vpfn); 253 } 254 return ret; 255 } 256 257 static int vfio_lock_acct(struct vfio_dma *dma, long npage, bool async) 258 { 259 struct mm_struct *mm; 260 int ret; 261 262 if (!npage) 263 return 0; 264 265 mm = async ? get_task_mm(dma->task) : dma->task->mm; 266 if (!mm) 267 return -ESRCH; /* process exited */ 268 269 ret = down_write_killable(&mm->mmap_sem); 270 if (!ret) { 271 if (npage > 0) { 272 if (!dma->lock_cap) { 273 unsigned long limit; 274 275 limit = task_rlimit(dma->task, 276 RLIMIT_MEMLOCK) >> PAGE_SHIFT; 277 278 if (mm->locked_vm + npage > limit) 279 ret = -ENOMEM; 280 } 281 } 282 283 if (!ret) 284 mm->locked_vm += npage; 285 286 up_write(&mm->mmap_sem); 287 } 288 289 if (async) 290 mmput(mm); 291 292 return ret; 293 } 294 295 /* 296 * Some mappings aren't backed by a struct page, for example an mmap'd 297 * MMIO range for our own or another device. These use a different 298 * pfn conversion and shouldn't be tracked as locked pages. 299 */ 300 static bool is_invalid_reserved_pfn(unsigned long pfn) 301 { 302 if (pfn_valid(pfn)) { 303 bool reserved; 304 struct page *tail = pfn_to_page(pfn); 305 struct page *head = compound_head(tail); 306 reserved = !!(PageReserved(head)); 307 if (head != tail) { 308 /* 309 * "head" is not a dangling pointer 310 * (compound_head takes care of that) 311 * but the hugepage may have been split 312 * from under us (and we may not hold a 313 * reference count on the head page so it can 314 * be reused before we run PageReferenced), so 315 * we've to check PageTail before returning 316 * what we just read. 317 */ 318 smp_rmb(); 319 if (PageTail(tail)) 320 return reserved; 321 } 322 return PageReserved(tail); 323 } 324 325 return true; 326 } 327 328 static int put_pfn(unsigned long pfn, int prot) 329 { 330 if (!is_invalid_reserved_pfn(pfn)) { 331 struct page *page = pfn_to_page(pfn); 332 if (prot & IOMMU_WRITE) 333 SetPageDirty(page); 334 put_page(page); 335 return 1; 336 } 337 return 0; 338 } 339 340 static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr, 341 int prot, unsigned long *pfn) 342 { 343 struct page *page[1]; 344 struct vm_area_struct *vma; 345 struct vm_area_struct *vmas[1]; 346 unsigned int flags = 0; 347 int ret; 348 349 if (prot & IOMMU_WRITE) 350 flags |= FOLL_WRITE; 351 352 down_read(&mm->mmap_sem); 353 if (mm == current->mm) { 354 ret = get_user_pages_longterm(vaddr, 1, flags, page, vmas); 355 } else { 356 ret = get_user_pages_remote(NULL, mm, vaddr, 1, flags, page, 357 vmas, NULL); 358 /* 359 * The lifetime of a vaddr_get_pfn() page pin is 360 * userspace-controlled. In the fs-dax case this could 361 * lead to indefinite stalls in filesystem operations. 362 * Disallow attempts to pin fs-dax pages via this 363 * interface. 364 */ 365 if (ret > 0 && vma_is_fsdax(vmas[0])) { 366 ret = -EOPNOTSUPP; 367 put_page(page[0]); 368 } 369 } 370 up_read(&mm->mmap_sem); 371 372 if (ret == 1) { 373 *pfn = page_to_pfn(page[0]); 374 return 0; 375 } 376 377 down_read(&mm->mmap_sem); 378 379 vma = find_vma_intersection(mm, vaddr, vaddr + 1); 380 381 if (vma && vma->vm_flags & VM_PFNMAP) { 382 *pfn = ((vaddr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff; 383 if (is_invalid_reserved_pfn(*pfn)) 384 ret = 0; 385 } 386 387 up_read(&mm->mmap_sem); 388 return ret; 389 } 390 391 /* 392 * Attempt to pin pages. We really don't want to track all the pfns and 393 * the iommu can only map chunks of consecutive pfns anyway, so get the 394 * first page and all consecutive pages with the same locking. 395 */ 396 static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr, 397 long npage, unsigned long *pfn_base, 398 unsigned long limit) 399 { 400 unsigned long pfn = 0; 401 long ret, pinned = 0, lock_acct = 0; 402 bool rsvd; 403 dma_addr_t iova = vaddr - dma->vaddr + dma->iova; 404 405 /* This code path is only user initiated */ 406 if (!current->mm) 407 return -ENODEV; 408 409 ret = vaddr_get_pfn(current->mm, vaddr, dma->prot, pfn_base); 410 if (ret) 411 return ret; 412 413 pinned++; 414 rsvd = is_invalid_reserved_pfn(*pfn_base); 415 416 /* 417 * Reserved pages aren't counted against the user, externally pinned 418 * pages are already counted against the user. 419 */ 420 if (!rsvd && !vfio_find_vpfn(dma, iova)) { 421 if (!dma->lock_cap && current->mm->locked_vm + 1 > limit) { 422 put_pfn(*pfn_base, dma->prot); 423 pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n", __func__, 424 limit << PAGE_SHIFT); 425 return -ENOMEM; 426 } 427 lock_acct++; 428 } 429 430 if (unlikely(disable_hugepages)) 431 goto out; 432 433 /* Lock all the consecutive pages from pfn_base */ 434 for (vaddr += PAGE_SIZE, iova += PAGE_SIZE; pinned < npage; 435 pinned++, vaddr += PAGE_SIZE, iova += PAGE_SIZE) { 436 ret = vaddr_get_pfn(current->mm, vaddr, dma->prot, &pfn); 437 if (ret) 438 break; 439 440 if (pfn != *pfn_base + pinned || 441 rsvd != is_invalid_reserved_pfn(pfn)) { 442 put_pfn(pfn, dma->prot); 443 break; 444 } 445 446 if (!rsvd && !vfio_find_vpfn(dma, iova)) { 447 if (!dma->lock_cap && 448 current->mm->locked_vm + lock_acct + 1 > limit) { 449 put_pfn(pfn, dma->prot); 450 pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n", 451 __func__, limit << PAGE_SHIFT); 452 ret = -ENOMEM; 453 goto unpin_out; 454 } 455 lock_acct++; 456 } 457 } 458 459 out: 460 ret = vfio_lock_acct(dma, lock_acct, false); 461 462 unpin_out: 463 if (ret) { 464 if (!rsvd) { 465 for (pfn = *pfn_base ; pinned ; pfn++, pinned--) 466 put_pfn(pfn, dma->prot); 467 } 468 469 return ret; 470 } 471 472 return pinned; 473 } 474 475 static long vfio_unpin_pages_remote(struct vfio_dma *dma, dma_addr_t iova, 476 unsigned long pfn, long npage, 477 bool do_accounting) 478 { 479 long unlocked = 0, locked = 0; 480 long i; 481 482 for (i = 0; i < npage; i++, iova += PAGE_SIZE) { 483 if (put_pfn(pfn++, dma->prot)) { 484 unlocked++; 485 if (vfio_find_vpfn(dma, iova)) 486 locked++; 487 } 488 } 489 490 if (do_accounting) 491 vfio_lock_acct(dma, locked - unlocked, true); 492 493 return unlocked; 494 } 495 496 static int vfio_pin_page_external(struct vfio_dma *dma, unsigned long vaddr, 497 unsigned long *pfn_base, bool do_accounting) 498 { 499 struct mm_struct *mm; 500 int ret; 501 502 mm = get_task_mm(dma->task); 503 if (!mm) 504 return -ENODEV; 505 506 ret = vaddr_get_pfn(mm, vaddr, dma->prot, pfn_base); 507 if (!ret && do_accounting && !is_invalid_reserved_pfn(*pfn_base)) { 508 ret = vfio_lock_acct(dma, 1, true); 509 if (ret) { 510 put_pfn(*pfn_base, dma->prot); 511 if (ret == -ENOMEM) 512 pr_warn("%s: Task %s (%d) RLIMIT_MEMLOCK " 513 "(%ld) exceeded\n", __func__, 514 dma->task->comm, task_pid_nr(dma->task), 515 task_rlimit(dma->task, RLIMIT_MEMLOCK)); 516 } 517 } 518 519 mmput(mm); 520 return ret; 521 } 522 523 static int vfio_unpin_page_external(struct vfio_dma *dma, dma_addr_t iova, 524 bool do_accounting) 525 { 526 int unlocked; 527 struct vfio_pfn *vpfn = vfio_find_vpfn(dma, iova); 528 529 if (!vpfn) 530 return 0; 531 532 unlocked = vfio_iova_put_vfio_pfn(dma, vpfn); 533 534 if (do_accounting) 535 vfio_lock_acct(dma, -unlocked, true); 536 537 return unlocked; 538 } 539 540 static int vfio_iommu_type1_pin_pages(void *iommu_data, 541 unsigned long *user_pfn, 542 int npage, int prot, 543 unsigned long *phys_pfn) 544 { 545 struct vfio_iommu *iommu = iommu_data; 546 int i, j, ret; 547 unsigned long remote_vaddr; 548 struct vfio_dma *dma; 549 bool do_accounting; 550 551 if (!iommu || !user_pfn || !phys_pfn) 552 return -EINVAL; 553 554 /* Supported for v2 version only */ 555 if (!iommu->v2) 556 return -EACCES; 557 558 mutex_lock(&iommu->lock); 559 560 /* Fail if notifier list is empty */ 561 if ((!iommu->external_domain) || (!iommu->notifier.head)) { 562 ret = -EINVAL; 563 goto pin_done; 564 } 565 566 /* 567 * If iommu capable domain exist in the container then all pages are 568 * already pinned and accounted. Accouting should be done if there is no 569 * iommu capable domain in the container. 570 */ 571 do_accounting = !IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu); 572 573 for (i = 0; i < npage; i++) { 574 dma_addr_t iova; 575 struct vfio_pfn *vpfn; 576 577 iova = user_pfn[i] << PAGE_SHIFT; 578 dma = vfio_find_dma(iommu, iova, PAGE_SIZE); 579 if (!dma) { 580 ret = -EINVAL; 581 goto pin_unwind; 582 } 583 584 if ((dma->prot & prot) != prot) { 585 ret = -EPERM; 586 goto pin_unwind; 587 } 588 589 vpfn = vfio_iova_get_vfio_pfn(dma, iova); 590 if (vpfn) { 591 phys_pfn[i] = vpfn->pfn; 592 continue; 593 } 594 595 remote_vaddr = dma->vaddr + iova - dma->iova; 596 ret = vfio_pin_page_external(dma, remote_vaddr, &phys_pfn[i], 597 do_accounting); 598 if (ret) 599 goto pin_unwind; 600 601 ret = vfio_add_to_pfn_list(dma, iova, phys_pfn[i]); 602 if (ret) { 603 vfio_unpin_page_external(dma, iova, do_accounting); 604 goto pin_unwind; 605 } 606 } 607 608 ret = i; 609 goto pin_done; 610 611 pin_unwind: 612 phys_pfn[i] = 0; 613 for (j = 0; j < i; j++) { 614 dma_addr_t iova; 615 616 iova = user_pfn[j] << PAGE_SHIFT; 617 dma = vfio_find_dma(iommu, iova, PAGE_SIZE); 618 vfio_unpin_page_external(dma, iova, do_accounting); 619 phys_pfn[j] = 0; 620 } 621 pin_done: 622 mutex_unlock(&iommu->lock); 623 return ret; 624 } 625 626 static int vfio_iommu_type1_unpin_pages(void *iommu_data, 627 unsigned long *user_pfn, 628 int npage) 629 { 630 struct vfio_iommu *iommu = iommu_data; 631 bool do_accounting; 632 int i; 633 634 if (!iommu || !user_pfn) 635 return -EINVAL; 636 637 /* Supported for v2 version only */ 638 if (!iommu->v2) 639 return -EACCES; 640 641 mutex_lock(&iommu->lock); 642 643 if (!iommu->external_domain) { 644 mutex_unlock(&iommu->lock); 645 return -EINVAL; 646 } 647 648 do_accounting = !IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu); 649 for (i = 0; i < npage; i++) { 650 struct vfio_dma *dma; 651 dma_addr_t iova; 652 653 iova = user_pfn[i] << PAGE_SHIFT; 654 dma = vfio_find_dma(iommu, iova, PAGE_SIZE); 655 if (!dma) 656 goto unpin_exit; 657 vfio_unpin_page_external(dma, iova, do_accounting); 658 } 659 660 unpin_exit: 661 mutex_unlock(&iommu->lock); 662 return i > npage ? npage : (i > 0 ? i : -EINVAL); 663 } 664 665 static long vfio_sync_unpin(struct vfio_dma *dma, struct vfio_domain *domain, 666 struct list_head *regions) 667 { 668 long unlocked = 0; 669 struct vfio_regions *entry, *next; 670 671 iommu_tlb_sync(domain->domain); 672 673 list_for_each_entry_safe(entry, next, regions, list) { 674 unlocked += vfio_unpin_pages_remote(dma, 675 entry->iova, 676 entry->phys >> PAGE_SHIFT, 677 entry->len >> PAGE_SHIFT, 678 false); 679 list_del(&entry->list); 680 kfree(entry); 681 } 682 683 cond_resched(); 684 685 return unlocked; 686 } 687 688 /* 689 * Generally, VFIO needs to unpin remote pages after each IOTLB flush. 690 * Therefore, when using IOTLB flush sync interface, VFIO need to keep track 691 * of these regions (currently using a list). 692 * 693 * This value specifies maximum number of regions for each IOTLB flush sync. 694 */ 695 #define VFIO_IOMMU_TLB_SYNC_MAX 512 696 697 static size_t unmap_unpin_fast(struct vfio_domain *domain, 698 struct vfio_dma *dma, dma_addr_t *iova, 699 size_t len, phys_addr_t phys, long *unlocked, 700 struct list_head *unmapped_list, 701 int *unmapped_cnt) 702 { 703 size_t unmapped = 0; 704 struct vfio_regions *entry = kzalloc(sizeof(*entry), GFP_KERNEL); 705 706 if (entry) { 707 unmapped = iommu_unmap_fast(domain->domain, *iova, len); 708 709 if (!unmapped) { 710 kfree(entry); 711 } else { 712 iommu_tlb_range_add(domain->domain, *iova, unmapped); 713 entry->iova = *iova; 714 entry->phys = phys; 715 entry->len = unmapped; 716 list_add_tail(&entry->list, unmapped_list); 717 718 *iova += unmapped; 719 (*unmapped_cnt)++; 720 } 721 } 722 723 /* 724 * Sync if the number of fast-unmap regions hits the limit 725 * or in case of errors. 726 */ 727 if (*unmapped_cnt >= VFIO_IOMMU_TLB_SYNC_MAX || !unmapped) { 728 *unlocked += vfio_sync_unpin(dma, domain, 729 unmapped_list); 730 *unmapped_cnt = 0; 731 } 732 733 return unmapped; 734 } 735 736 static size_t unmap_unpin_slow(struct vfio_domain *domain, 737 struct vfio_dma *dma, dma_addr_t *iova, 738 size_t len, phys_addr_t phys, 739 long *unlocked) 740 { 741 size_t unmapped = iommu_unmap(domain->domain, *iova, len); 742 743 if (unmapped) { 744 *unlocked += vfio_unpin_pages_remote(dma, *iova, 745 phys >> PAGE_SHIFT, 746 unmapped >> PAGE_SHIFT, 747 false); 748 *iova += unmapped; 749 cond_resched(); 750 } 751 return unmapped; 752 } 753 754 static long vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma, 755 bool do_accounting) 756 { 757 dma_addr_t iova = dma->iova, end = dma->iova + dma->size; 758 struct vfio_domain *domain, *d; 759 LIST_HEAD(unmapped_region_list); 760 int unmapped_region_cnt = 0; 761 long unlocked = 0; 762 763 if (!dma->size) 764 return 0; 765 766 if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu)) 767 return 0; 768 769 /* 770 * We use the IOMMU to track the physical addresses, otherwise we'd 771 * need a much more complicated tracking system. Unfortunately that 772 * means we need to use one of the iommu domains to figure out the 773 * pfns to unpin. The rest need to be unmapped in advance so we have 774 * no iommu translations remaining when the pages are unpinned. 775 */ 776 domain = d = list_first_entry(&iommu->domain_list, 777 struct vfio_domain, next); 778 779 list_for_each_entry_continue(d, &iommu->domain_list, next) { 780 iommu_unmap(d->domain, dma->iova, dma->size); 781 cond_resched(); 782 } 783 784 while (iova < end) { 785 size_t unmapped, len; 786 phys_addr_t phys, next; 787 788 phys = iommu_iova_to_phys(domain->domain, iova); 789 if (WARN_ON(!phys)) { 790 iova += PAGE_SIZE; 791 continue; 792 } 793 794 /* 795 * To optimize for fewer iommu_unmap() calls, each of which 796 * may require hardware cache flushing, try to find the 797 * largest contiguous physical memory chunk to unmap. 798 */ 799 for (len = PAGE_SIZE; 800 !domain->fgsp && iova + len < end; len += PAGE_SIZE) { 801 next = iommu_iova_to_phys(domain->domain, iova + len); 802 if (next != phys + len) 803 break; 804 } 805 806 /* 807 * First, try to use fast unmap/unpin. In case of failure, 808 * switch to slow unmap/unpin path. 809 */ 810 unmapped = unmap_unpin_fast(domain, dma, &iova, len, phys, 811 &unlocked, &unmapped_region_list, 812 &unmapped_region_cnt); 813 if (!unmapped) { 814 unmapped = unmap_unpin_slow(domain, dma, &iova, len, 815 phys, &unlocked); 816 if (WARN_ON(!unmapped)) 817 break; 818 } 819 } 820 821 dma->iommu_mapped = false; 822 823 if (unmapped_region_cnt) 824 unlocked += vfio_sync_unpin(dma, domain, &unmapped_region_list); 825 826 if (do_accounting) { 827 vfio_lock_acct(dma, -unlocked, true); 828 return 0; 829 } 830 return unlocked; 831 } 832 833 static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma) 834 { 835 vfio_unmap_unpin(iommu, dma, true); 836 vfio_unlink_dma(iommu, dma); 837 put_task_struct(dma->task); 838 kfree(dma); 839 } 840 841 static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu) 842 { 843 struct vfio_domain *domain; 844 unsigned long bitmap = ULONG_MAX; 845 846 mutex_lock(&iommu->lock); 847 list_for_each_entry(domain, &iommu->domain_list, next) 848 bitmap &= domain->domain->pgsize_bitmap; 849 mutex_unlock(&iommu->lock); 850 851 /* 852 * In case the IOMMU supports page sizes smaller than PAGE_SIZE 853 * we pretend PAGE_SIZE is supported and hide sub-PAGE_SIZE sizes. 854 * That way the user will be able to map/unmap buffers whose size/ 855 * start address is aligned with PAGE_SIZE. Pinning code uses that 856 * granularity while iommu driver can use the sub-PAGE_SIZE size 857 * to map the buffer. 858 */ 859 if (bitmap & ~PAGE_MASK) { 860 bitmap &= PAGE_MASK; 861 bitmap |= PAGE_SIZE; 862 } 863 864 return bitmap; 865 } 866 867 static int vfio_dma_do_unmap(struct vfio_iommu *iommu, 868 struct vfio_iommu_type1_dma_unmap *unmap) 869 { 870 uint64_t mask; 871 struct vfio_dma *dma, *dma_last = NULL; 872 size_t unmapped = 0; 873 int ret = 0, retries = 0; 874 875 mask = ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1; 876 877 if (unmap->iova & mask) 878 return -EINVAL; 879 if (!unmap->size || unmap->size & mask) 880 return -EINVAL; 881 if (unmap->iova + unmap->size < unmap->iova || 882 unmap->size > SIZE_MAX) 883 return -EINVAL; 884 885 WARN_ON(mask & PAGE_MASK); 886 again: 887 mutex_lock(&iommu->lock); 888 889 /* 890 * vfio-iommu-type1 (v1) - User mappings were coalesced together to 891 * avoid tracking individual mappings. This means that the granularity 892 * of the original mapping was lost and the user was allowed to attempt 893 * to unmap any range. Depending on the contiguousness of physical 894 * memory and page sizes supported by the IOMMU, arbitrary unmaps may 895 * or may not have worked. We only guaranteed unmap granularity 896 * matching the original mapping; even though it was untracked here, 897 * the original mappings are reflected in IOMMU mappings. This 898 * resulted in a couple unusual behaviors. First, if a range is not 899 * able to be unmapped, ex. a set of 4k pages that was mapped as a 900 * 2M hugepage into the IOMMU, the unmap ioctl returns success but with 901 * a zero sized unmap. Also, if an unmap request overlaps the first 902 * address of a hugepage, the IOMMU will unmap the entire hugepage. 903 * This also returns success and the returned unmap size reflects the 904 * actual size unmapped. 905 * 906 * We attempt to maintain compatibility with this "v1" interface, but 907 * we take control out of the hands of the IOMMU. Therefore, an unmap 908 * request offset from the beginning of the original mapping will 909 * return success with zero sized unmap. And an unmap request covering 910 * the first iova of mapping will unmap the entire range. 911 * 912 * The v2 version of this interface intends to be more deterministic. 913 * Unmap requests must fully cover previous mappings. Multiple 914 * mappings may still be unmaped by specifying large ranges, but there 915 * must not be any previous mappings bisected by the range. An error 916 * will be returned if these conditions are not met. The v2 interface 917 * will only return success and a size of zero if there were no 918 * mappings within the range. 919 */ 920 if (iommu->v2) { 921 dma = vfio_find_dma(iommu, unmap->iova, 1); 922 if (dma && dma->iova != unmap->iova) { 923 ret = -EINVAL; 924 goto unlock; 925 } 926 dma = vfio_find_dma(iommu, unmap->iova + unmap->size - 1, 0); 927 if (dma && dma->iova + dma->size != unmap->iova + unmap->size) { 928 ret = -EINVAL; 929 goto unlock; 930 } 931 } 932 933 while ((dma = vfio_find_dma(iommu, unmap->iova, unmap->size))) { 934 if (!iommu->v2 && unmap->iova > dma->iova) 935 break; 936 /* 937 * Task with same address space who mapped this iova range is 938 * allowed to unmap the iova range. 939 */ 940 if (dma->task->mm != current->mm) 941 break; 942 943 if (!RB_EMPTY_ROOT(&dma->pfn_list)) { 944 struct vfio_iommu_type1_dma_unmap nb_unmap; 945 946 if (dma_last == dma) { 947 BUG_ON(++retries > 10); 948 } else { 949 dma_last = dma; 950 retries = 0; 951 } 952 953 nb_unmap.iova = dma->iova; 954 nb_unmap.size = dma->size; 955 956 /* 957 * Notify anyone (mdev vendor drivers) to invalidate and 958 * unmap iovas within the range we're about to unmap. 959 * Vendor drivers MUST unpin pages in response to an 960 * invalidation. 961 */ 962 mutex_unlock(&iommu->lock); 963 blocking_notifier_call_chain(&iommu->notifier, 964 VFIO_IOMMU_NOTIFY_DMA_UNMAP, 965 &nb_unmap); 966 goto again; 967 } 968 unmapped += dma->size; 969 vfio_remove_dma(iommu, dma); 970 } 971 972 unlock: 973 mutex_unlock(&iommu->lock); 974 975 /* Report how much was unmapped */ 976 unmap->size = unmapped; 977 978 return ret; 979 } 980 981 /* 982 * Turns out AMD IOMMU has a page table bug where it won't map large pages 983 * to a region that previously mapped smaller pages. This should be fixed 984 * soon, so this is just a temporary workaround to break mappings down into 985 * PAGE_SIZE. Better to map smaller pages than nothing. 986 */ 987 static int map_try_harder(struct vfio_domain *domain, dma_addr_t iova, 988 unsigned long pfn, long npage, int prot) 989 { 990 long i; 991 int ret = 0; 992 993 for (i = 0; i < npage; i++, pfn++, iova += PAGE_SIZE) { 994 ret = iommu_map(domain->domain, iova, 995 (phys_addr_t)pfn << PAGE_SHIFT, 996 PAGE_SIZE, prot | domain->prot); 997 if (ret) 998 break; 999 } 1000 1001 for (; i < npage && i > 0; i--, iova -= PAGE_SIZE) 1002 iommu_unmap(domain->domain, iova, PAGE_SIZE); 1003 1004 return ret; 1005 } 1006 1007 static int vfio_iommu_map(struct vfio_iommu *iommu, dma_addr_t iova, 1008 unsigned long pfn, long npage, int prot) 1009 { 1010 struct vfio_domain *d; 1011 int ret; 1012 1013 list_for_each_entry(d, &iommu->domain_list, next) { 1014 ret = iommu_map(d->domain, iova, (phys_addr_t)pfn << PAGE_SHIFT, 1015 npage << PAGE_SHIFT, prot | d->prot); 1016 if (ret) { 1017 if (ret != -EBUSY || 1018 map_try_harder(d, iova, pfn, npage, prot)) 1019 goto unwind; 1020 } 1021 1022 cond_resched(); 1023 } 1024 1025 return 0; 1026 1027 unwind: 1028 list_for_each_entry_continue_reverse(d, &iommu->domain_list, next) 1029 iommu_unmap(d->domain, iova, npage << PAGE_SHIFT); 1030 1031 return ret; 1032 } 1033 1034 static int vfio_pin_map_dma(struct vfio_iommu *iommu, struct vfio_dma *dma, 1035 size_t map_size) 1036 { 1037 dma_addr_t iova = dma->iova; 1038 unsigned long vaddr = dma->vaddr; 1039 size_t size = map_size; 1040 long npage; 1041 unsigned long pfn, limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 1042 int ret = 0; 1043 1044 while (size) { 1045 /* Pin a contiguous chunk of memory */ 1046 npage = vfio_pin_pages_remote(dma, vaddr + dma->size, 1047 size >> PAGE_SHIFT, &pfn, limit); 1048 if (npage <= 0) { 1049 WARN_ON(!npage); 1050 ret = (int)npage; 1051 break; 1052 } 1053 1054 /* Map it! */ 1055 ret = vfio_iommu_map(iommu, iova + dma->size, pfn, npage, 1056 dma->prot); 1057 if (ret) { 1058 vfio_unpin_pages_remote(dma, iova + dma->size, pfn, 1059 npage, true); 1060 break; 1061 } 1062 1063 size -= npage << PAGE_SHIFT; 1064 dma->size += npage << PAGE_SHIFT; 1065 } 1066 1067 dma->iommu_mapped = true; 1068 1069 if (ret) 1070 vfio_remove_dma(iommu, dma); 1071 1072 return ret; 1073 } 1074 1075 static int vfio_dma_do_map(struct vfio_iommu *iommu, 1076 struct vfio_iommu_type1_dma_map *map) 1077 { 1078 dma_addr_t iova = map->iova; 1079 unsigned long vaddr = map->vaddr; 1080 size_t size = map->size; 1081 int ret = 0, prot = 0; 1082 uint64_t mask; 1083 struct vfio_dma *dma; 1084 1085 /* Verify that none of our __u64 fields overflow */ 1086 if (map->size != size || map->vaddr != vaddr || map->iova != iova) 1087 return -EINVAL; 1088 1089 mask = ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1; 1090 1091 WARN_ON(mask & PAGE_MASK); 1092 1093 /* READ/WRITE from device perspective */ 1094 if (map->flags & VFIO_DMA_MAP_FLAG_WRITE) 1095 prot |= IOMMU_WRITE; 1096 if (map->flags & VFIO_DMA_MAP_FLAG_READ) 1097 prot |= IOMMU_READ; 1098 1099 if (!prot || !size || (size | iova | vaddr) & mask) 1100 return -EINVAL; 1101 1102 /* Don't allow IOVA or virtual address wrap */ 1103 if (iova + size - 1 < iova || vaddr + size - 1 < vaddr) 1104 return -EINVAL; 1105 1106 mutex_lock(&iommu->lock); 1107 1108 if (vfio_find_dma(iommu, iova, size)) { 1109 ret = -EEXIST; 1110 goto out_unlock; 1111 } 1112 1113 dma = kzalloc(sizeof(*dma), GFP_KERNEL); 1114 if (!dma) { 1115 ret = -ENOMEM; 1116 goto out_unlock; 1117 } 1118 1119 dma->iova = iova; 1120 dma->vaddr = vaddr; 1121 dma->prot = prot; 1122 1123 /* 1124 * We need to be able to both add to a task's locked memory and test 1125 * against the locked memory limit and we need to be able to do both 1126 * outside of this call path as pinning can be asynchronous via the 1127 * external interfaces for mdev devices. RLIMIT_MEMLOCK requires a 1128 * task_struct and VM locked pages requires an mm_struct, however 1129 * holding an indefinite mm reference is not recommended, therefore we 1130 * only hold a reference to a task. We could hold a reference to 1131 * current, however QEMU uses this call path through vCPU threads, 1132 * which can be killed resulting in a NULL mm and failure in the unmap 1133 * path when called via a different thread. Avoid this problem by 1134 * using the group_leader as threads within the same group require 1135 * both CLONE_THREAD and CLONE_VM and will therefore use the same 1136 * mm_struct. 1137 * 1138 * Previously we also used the task for testing CAP_IPC_LOCK at the 1139 * time of pinning and accounting, however has_capability() makes use 1140 * of real_cred, a copy-on-write field, so we can't guarantee that it 1141 * matches group_leader, or in fact that it might not change by the 1142 * time it's evaluated. If a process were to call MAP_DMA with 1143 * CAP_IPC_LOCK but later drop it, it doesn't make sense that they 1144 * possibly see different results for an iommu_mapped vfio_dma vs 1145 * externally mapped. Therefore track CAP_IPC_LOCK in vfio_dma at the 1146 * time of calling MAP_DMA. 1147 */ 1148 get_task_struct(current->group_leader); 1149 dma->task = current->group_leader; 1150 dma->lock_cap = capable(CAP_IPC_LOCK); 1151 1152 dma->pfn_list = RB_ROOT; 1153 1154 /* Insert zero-sized and grow as we map chunks of it */ 1155 vfio_link_dma(iommu, dma); 1156 1157 /* Don't pin and map if container doesn't contain IOMMU capable domain*/ 1158 if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu)) 1159 dma->size = size; 1160 else 1161 ret = vfio_pin_map_dma(iommu, dma, size); 1162 1163 out_unlock: 1164 mutex_unlock(&iommu->lock); 1165 return ret; 1166 } 1167 1168 static int vfio_bus_type(struct device *dev, void *data) 1169 { 1170 struct bus_type **bus = data; 1171 1172 if (*bus && *bus != dev->bus) 1173 return -EINVAL; 1174 1175 *bus = dev->bus; 1176 1177 return 0; 1178 } 1179 1180 static int vfio_iommu_replay(struct vfio_iommu *iommu, 1181 struct vfio_domain *domain) 1182 { 1183 struct vfio_domain *d; 1184 struct rb_node *n; 1185 unsigned long limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 1186 int ret; 1187 1188 /* Arbitrarily pick the first domain in the list for lookups */ 1189 d = list_first_entry(&iommu->domain_list, struct vfio_domain, next); 1190 n = rb_first(&iommu->dma_list); 1191 1192 for (; n; n = rb_next(n)) { 1193 struct vfio_dma *dma; 1194 dma_addr_t iova; 1195 1196 dma = rb_entry(n, struct vfio_dma, node); 1197 iova = dma->iova; 1198 1199 while (iova < dma->iova + dma->size) { 1200 phys_addr_t phys; 1201 size_t size; 1202 1203 if (dma->iommu_mapped) { 1204 phys_addr_t p; 1205 dma_addr_t i; 1206 1207 phys = iommu_iova_to_phys(d->domain, iova); 1208 1209 if (WARN_ON(!phys)) { 1210 iova += PAGE_SIZE; 1211 continue; 1212 } 1213 1214 size = PAGE_SIZE; 1215 p = phys + size; 1216 i = iova + size; 1217 while (i < dma->iova + dma->size && 1218 p == iommu_iova_to_phys(d->domain, i)) { 1219 size += PAGE_SIZE; 1220 p += PAGE_SIZE; 1221 i += PAGE_SIZE; 1222 } 1223 } else { 1224 unsigned long pfn; 1225 unsigned long vaddr = dma->vaddr + 1226 (iova - dma->iova); 1227 size_t n = dma->iova + dma->size - iova; 1228 long npage; 1229 1230 npage = vfio_pin_pages_remote(dma, vaddr, 1231 n >> PAGE_SHIFT, 1232 &pfn, limit); 1233 if (npage <= 0) { 1234 WARN_ON(!npage); 1235 ret = (int)npage; 1236 return ret; 1237 } 1238 1239 phys = pfn << PAGE_SHIFT; 1240 size = npage << PAGE_SHIFT; 1241 } 1242 1243 ret = iommu_map(domain->domain, iova, phys, 1244 size, dma->prot | domain->prot); 1245 if (ret) 1246 return ret; 1247 1248 iova += size; 1249 } 1250 dma->iommu_mapped = true; 1251 } 1252 return 0; 1253 } 1254 1255 /* 1256 * We change our unmap behavior slightly depending on whether the IOMMU 1257 * supports fine-grained superpages. IOMMUs like AMD-Vi will use a superpage 1258 * for practically any contiguous power-of-two mapping we give it. This means 1259 * we don't need to look for contiguous chunks ourselves to make unmapping 1260 * more efficient. On IOMMUs with coarse-grained super pages, like Intel VT-d 1261 * with discrete 2M/1G/512G/1T superpages, identifying contiguous chunks 1262 * significantly boosts non-hugetlbfs mappings and doesn't seem to hurt when 1263 * hugetlbfs is in use. 1264 */ 1265 static void vfio_test_domain_fgsp(struct vfio_domain *domain) 1266 { 1267 struct page *pages; 1268 int ret, order = get_order(PAGE_SIZE * 2); 1269 1270 pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, order); 1271 if (!pages) 1272 return; 1273 1274 ret = iommu_map(domain->domain, 0, page_to_phys(pages), PAGE_SIZE * 2, 1275 IOMMU_READ | IOMMU_WRITE | domain->prot); 1276 if (!ret) { 1277 size_t unmapped = iommu_unmap(domain->domain, 0, PAGE_SIZE); 1278 1279 if (unmapped == PAGE_SIZE) 1280 iommu_unmap(domain->domain, PAGE_SIZE, PAGE_SIZE); 1281 else 1282 domain->fgsp = true; 1283 } 1284 1285 __free_pages(pages, order); 1286 } 1287 1288 static struct vfio_group *find_iommu_group(struct vfio_domain *domain, 1289 struct iommu_group *iommu_group) 1290 { 1291 struct vfio_group *g; 1292 1293 list_for_each_entry(g, &domain->group_list, next) { 1294 if (g->iommu_group == iommu_group) 1295 return g; 1296 } 1297 1298 return NULL; 1299 } 1300 1301 static bool vfio_iommu_has_sw_msi(struct iommu_group *group, phys_addr_t *base) 1302 { 1303 struct list_head group_resv_regions; 1304 struct iommu_resv_region *region, *next; 1305 bool ret = false; 1306 1307 INIT_LIST_HEAD(&group_resv_regions); 1308 iommu_get_group_resv_regions(group, &group_resv_regions); 1309 list_for_each_entry(region, &group_resv_regions, list) { 1310 /* 1311 * The presence of any 'real' MSI regions should take 1312 * precedence over the software-managed one if the 1313 * IOMMU driver happens to advertise both types. 1314 */ 1315 if (region->type == IOMMU_RESV_MSI) { 1316 ret = false; 1317 break; 1318 } 1319 1320 if (region->type == IOMMU_RESV_SW_MSI) { 1321 *base = region->start; 1322 ret = true; 1323 } 1324 } 1325 list_for_each_entry_safe(region, next, &group_resv_regions, list) 1326 kfree(region); 1327 return ret; 1328 } 1329 1330 static int vfio_iommu_type1_attach_group(void *iommu_data, 1331 struct iommu_group *iommu_group) 1332 { 1333 struct vfio_iommu *iommu = iommu_data; 1334 struct vfio_group *group; 1335 struct vfio_domain *domain, *d; 1336 struct bus_type *bus = NULL, *mdev_bus; 1337 int ret; 1338 bool resv_msi, msi_remap; 1339 phys_addr_t resv_msi_base; 1340 1341 mutex_lock(&iommu->lock); 1342 1343 list_for_each_entry(d, &iommu->domain_list, next) { 1344 if (find_iommu_group(d, iommu_group)) { 1345 mutex_unlock(&iommu->lock); 1346 return -EINVAL; 1347 } 1348 } 1349 1350 if (iommu->external_domain) { 1351 if (find_iommu_group(iommu->external_domain, iommu_group)) { 1352 mutex_unlock(&iommu->lock); 1353 return -EINVAL; 1354 } 1355 } 1356 1357 group = kzalloc(sizeof(*group), GFP_KERNEL); 1358 domain = kzalloc(sizeof(*domain), GFP_KERNEL); 1359 if (!group || !domain) { 1360 ret = -ENOMEM; 1361 goto out_free; 1362 } 1363 1364 group->iommu_group = iommu_group; 1365 1366 /* Determine bus_type in order to allocate a domain */ 1367 ret = iommu_group_for_each_dev(iommu_group, &bus, vfio_bus_type); 1368 if (ret) 1369 goto out_free; 1370 1371 mdev_bus = symbol_get(mdev_bus_type); 1372 1373 if (mdev_bus) { 1374 if ((bus == mdev_bus) && !iommu_present(bus)) { 1375 symbol_put(mdev_bus_type); 1376 if (!iommu->external_domain) { 1377 INIT_LIST_HEAD(&domain->group_list); 1378 iommu->external_domain = domain; 1379 } else 1380 kfree(domain); 1381 1382 list_add(&group->next, 1383 &iommu->external_domain->group_list); 1384 mutex_unlock(&iommu->lock); 1385 return 0; 1386 } 1387 symbol_put(mdev_bus_type); 1388 } 1389 1390 domain->domain = iommu_domain_alloc(bus); 1391 if (!domain->domain) { 1392 ret = -EIO; 1393 goto out_free; 1394 } 1395 1396 if (iommu->nesting) { 1397 int attr = 1; 1398 1399 ret = iommu_domain_set_attr(domain->domain, DOMAIN_ATTR_NESTING, 1400 &attr); 1401 if (ret) 1402 goto out_domain; 1403 } 1404 1405 ret = iommu_attach_group(domain->domain, iommu_group); 1406 if (ret) 1407 goto out_domain; 1408 1409 resv_msi = vfio_iommu_has_sw_msi(iommu_group, &resv_msi_base); 1410 1411 INIT_LIST_HEAD(&domain->group_list); 1412 list_add(&group->next, &domain->group_list); 1413 1414 msi_remap = irq_domain_check_msi_remap() || 1415 iommu_capable(bus, IOMMU_CAP_INTR_REMAP); 1416 1417 if (!allow_unsafe_interrupts && !msi_remap) { 1418 pr_warn("%s: No interrupt remapping support. Use the module param \"allow_unsafe_interrupts\" to enable VFIO IOMMU support on this platform\n", 1419 __func__); 1420 ret = -EPERM; 1421 goto out_detach; 1422 } 1423 1424 if (iommu_capable(bus, IOMMU_CAP_CACHE_COHERENCY)) 1425 domain->prot |= IOMMU_CACHE; 1426 1427 /* 1428 * Try to match an existing compatible domain. We don't want to 1429 * preclude an IOMMU driver supporting multiple bus_types and being 1430 * able to include different bus_types in the same IOMMU domain, so 1431 * we test whether the domains use the same iommu_ops rather than 1432 * testing if they're on the same bus_type. 1433 */ 1434 list_for_each_entry(d, &iommu->domain_list, next) { 1435 if (d->domain->ops == domain->domain->ops && 1436 d->prot == domain->prot) { 1437 iommu_detach_group(domain->domain, iommu_group); 1438 if (!iommu_attach_group(d->domain, iommu_group)) { 1439 list_add(&group->next, &d->group_list); 1440 iommu_domain_free(domain->domain); 1441 kfree(domain); 1442 mutex_unlock(&iommu->lock); 1443 return 0; 1444 } 1445 1446 ret = iommu_attach_group(domain->domain, iommu_group); 1447 if (ret) 1448 goto out_domain; 1449 } 1450 } 1451 1452 vfio_test_domain_fgsp(domain); 1453 1454 /* replay mappings on new domains */ 1455 ret = vfio_iommu_replay(iommu, domain); 1456 if (ret) 1457 goto out_detach; 1458 1459 if (resv_msi) { 1460 ret = iommu_get_msi_cookie(domain->domain, resv_msi_base); 1461 if (ret) 1462 goto out_detach; 1463 } 1464 1465 list_add(&domain->next, &iommu->domain_list); 1466 1467 mutex_unlock(&iommu->lock); 1468 1469 return 0; 1470 1471 out_detach: 1472 iommu_detach_group(domain->domain, iommu_group); 1473 out_domain: 1474 iommu_domain_free(domain->domain); 1475 out_free: 1476 kfree(domain); 1477 kfree(group); 1478 mutex_unlock(&iommu->lock); 1479 return ret; 1480 } 1481 1482 static void vfio_iommu_unmap_unpin_all(struct vfio_iommu *iommu) 1483 { 1484 struct rb_node *node; 1485 1486 while ((node = rb_first(&iommu->dma_list))) 1487 vfio_remove_dma(iommu, rb_entry(node, struct vfio_dma, node)); 1488 } 1489 1490 static void vfio_iommu_unmap_unpin_reaccount(struct vfio_iommu *iommu) 1491 { 1492 struct rb_node *n, *p; 1493 1494 n = rb_first(&iommu->dma_list); 1495 for (; n; n = rb_next(n)) { 1496 struct vfio_dma *dma; 1497 long locked = 0, unlocked = 0; 1498 1499 dma = rb_entry(n, struct vfio_dma, node); 1500 unlocked += vfio_unmap_unpin(iommu, dma, false); 1501 p = rb_first(&dma->pfn_list); 1502 for (; p; p = rb_next(p)) { 1503 struct vfio_pfn *vpfn = rb_entry(p, struct vfio_pfn, 1504 node); 1505 1506 if (!is_invalid_reserved_pfn(vpfn->pfn)) 1507 locked++; 1508 } 1509 vfio_lock_acct(dma, locked - unlocked, true); 1510 } 1511 } 1512 1513 static void vfio_sanity_check_pfn_list(struct vfio_iommu *iommu) 1514 { 1515 struct rb_node *n; 1516 1517 n = rb_first(&iommu->dma_list); 1518 for (; n; n = rb_next(n)) { 1519 struct vfio_dma *dma; 1520 1521 dma = rb_entry(n, struct vfio_dma, node); 1522 1523 if (WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list))) 1524 break; 1525 } 1526 /* mdev vendor driver must unregister notifier */ 1527 WARN_ON(iommu->notifier.head); 1528 } 1529 1530 static void vfio_iommu_type1_detach_group(void *iommu_data, 1531 struct iommu_group *iommu_group) 1532 { 1533 struct vfio_iommu *iommu = iommu_data; 1534 struct vfio_domain *domain; 1535 struct vfio_group *group; 1536 1537 mutex_lock(&iommu->lock); 1538 1539 if (iommu->external_domain) { 1540 group = find_iommu_group(iommu->external_domain, iommu_group); 1541 if (group) { 1542 list_del(&group->next); 1543 kfree(group); 1544 1545 if (list_empty(&iommu->external_domain->group_list)) { 1546 vfio_sanity_check_pfn_list(iommu); 1547 1548 if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu)) 1549 vfio_iommu_unmap_unpin_all(iommu); 1550 1551 kfree(iommu->external_domain); 1552 iommu->external_domain = NULL; 1553 } 1554 goto detach_group_done; 1555 } 1556 } 1557 1558 list_for_each_entry(domain, &iommu->domain_list, next) { 1559 group = find_iommu_group(domain, iommu_group); 1560 if (!group) 1561 continue; 1562 1563 iommu_detach_group(domain->domain, iommu_group); 1564 list_del(&group->next); 1565 kfree(group); 1566 /* 1567 * Group ownership provides privilege, if the group list is 1568 * empty, the domain goes away. If it's the last domain with 1569 * iommu and external domain doesn't exist, then all the 1570 * mappings go away too. If it's the last domain with iommu and 1571 * external domain exist, update accounting 1572 */ 1573 if (list_empty(&domain->group_list)) { 1574 if (list_is_singular(&iommu->domain_list)) { 1575 if (!iommu->external_domain) 1576 vfio_iommu_unmap_unpin_all(iommu); 1577 else 1578 vfio_iommu_unmap_unpin_reaccount(iommu); 1579 } 1580 iommu_domain_free(domain->domain); 1581 list_del(&domain->next); 1582 kfree(domain); 1583 } 1584 break; 1585 } 1586 1587 detach_group_done: 1588 mutex_unlock(&iommu->lock); 1589 } 1590 1591 static void *vfio_iommu_type1_open(unsigned long arg) 1592 { 1593 struct vfio_iommu *iommu; 1594 1595 iommu = kzalloc(sizeof(*iommu), GFP_KERNEL); 1596 if (!iommu) 1597 return ERR_PTR(-ENOMEM); 1598 1599 switch (arg) { 1600 case VFIO_TYPE1_IOMMU: 1601 break; 1602 case VFIO_TYPE1_NESTING_IOMMU: 1603 iommu->nesting = true; 1604 /* fall through */ 1605 case VFIO_TYPE1v2_IOMMU: 1606 iommu->v2 = true; 1607 break; 1608 default: 1609 kfree(iommu); 1610 return ERR_PTR(-EINVAL); 1611 } 1612 1613 INIT_LIST_HEAD(&iommu->domain_list); 1614 iommu->dma_list = RB_ROOT; 1615 mutex_init(&iommu->lock); 1616 BLOCKING_INIT_NOTIFIER_HEAD(&iommu->notifier); 1617 1618 return iommu; 1619 } 1620 1621 static void vfio_release_domain(struct vfio_domain *domain, bool external) 1622 { 1623 struct vfio_group *group, *group_tmp; 1624 1625 list_for_each_entry_safe(group, group_tmp, 1626 &domain->group_list, next) { 1627 if (!external) 1628 iommu_detach_group(domain->domain, group->iommu_group); 1629 list_del(&group->next); 1630 kfree(group); 1631 } 1632 1633 if (!external) 1634 iommu_domain_free(domain->domain); 1635 } 1636 1637 static void vfio_iommu_type1_release(void *iommu_data) 1638 { 1639 struct vfio_iommu *iommu = iommu_data; 1640 struct vfio_domain *domain, *domain_tmp; 1641 1642 if (iommu->external_domain) { 1643 vfio_release_domain(iommu->external_domain, true); 1644 vfio_sanity_check_pfn_list(iommu); 1645 kfree(iommu->external_domain); 1646 } 1647 1648 vfio_iommu_unmap_unpin_all(iommu); 1649 1650 list_for_each_entry_safe(domain, domain_tmp, 1651 &iommu->domain_list, next) { 1652 vfio_release_domain(domain, false); 1653 list_del(&domain->next); 1654 kfree(domain); 1655 } 1656 kfree(iommu); 1657 } 1658 1659 static int vfio_domains_have_iommu_cache(struct vfio_iommu *iommu) 1660 { 1661 struct vfio_domain *domain; 1662 int ret = 1; 1663 1664 mutex_lock(&iommu->lock); 1665 list_for_each_entry(domain, &iommu->domain_list, next) { 1666 if (!(domain->prot & IOMMU_CACHE)) { 1667 ret = 0; 1668 break; 1669 } 1670 } 1671 mutex_unlock(&iommu->lock); 1672 1673 return ret; 1674 } 1675 1676 static long vfio_iommu_type1_ioctl(void *iommu_data, 1677 unsigned int cmd, unsigned long arg) 1678 { 1679 struct vfio_iommu *iommu = iommu_data; 1680 unsigned long minsz; 1681 1682 if (cmd == VFIO_CHECK_EXTENSION) { 1683 switch (arg) { 1684 case VFIO_TYPE1_IOMMU: 1685 case VFIO_TYPE1v2_IOMMU: 1686 case VFIO_TYPE1_NESTING_IOMMU: 1687 return 1; 1688 case VFIO_DMA_CC_IOMMU: 1689 if (!iommu) 1690 return 0; 1691 return vfio_domains_have_iommu_cache(iommu); 1692 default: 1693 return 0; 1694 } 1695 } else if (cmd == VFIO_IOMMU_GET_INFO) { 1696 struct vfio_iommu_type1_info info; 1697 1698 minsz = offsetofend(struct vfio_iommu_type1_info, iova_pgsizes); 1699 1700 if (copy_from_user(&info, (void __user *)arg, minsz)) 1701 return -EFAULT; 1702 1703 if (info.argsz < minsz) 1704 return -EINVAL; 1705 1706 info.flags = VFIO_IOMMU_INFO_PGSIZES; 1707 1708 info.iova_pgsizes = vfio_pgsize_bitmap(iommu); 1709 1710 return copy_to_user((void __user *)arg, &info, minsz) ? 1711 -EFAULT : 0; 1712 1713 } else if (cmd == VFIO_IOMMU_MAP_DMA) { 1714 struct vfio_iommu_type1_dma_map map; 1715 uint32_t mask = VFIO_DMA_MAP_FLAG_READ | 1716 VFIO_DMA_MAP_FLAG_WRITE; 1717 1718 minsz = offsetofend(struct vfio_iommu_type1_dma_map, size); 1719 1720 if (copy_from_user(&map, (void __user *)arg, minsz)) 1721 return -EFAULT; 1722 1723 if (map.argsz < minsz || map.flags & ~mask) 1724 return -EINVAL; 1725 1726 return vfio_dma_do_map(iommu, &map); 1727 1728 } else if (cmd == VFIO_IOMMU_UNMAP_DMA) { 1729 struct vfio_iommu_type1_dma_unmap unmap; 1730 long ret; 1731 1732 minsz = offsetofend(struct vfio_iommu_type1_dma_unmap, size); 1733 1734 if (copy_from_user(&unmap, (void __user *)arg, minsz)) 1735 return -EFAULT; 1736 1737 if (unmap.argsz < minsz || unmap.flags) 1738 return -EINVAL; 1739 1740 ret = vfio_dma_do_unmap(iommu, &unmap); 1741 if (ret) 1742 return ret; 1743 1744 return copy_to_user((void __user *)arg, &unmap, minsz) ? 1745 -EFAULT : 0; 1746 } 1747 1748 return -ENOTTY; 1749 } 1750 1751 static int vfio_iommu_type1_register_notifier(void *iommu_data, 1752 unsigned long *events, 1753 struct notifier_block *nb) 1754 { 1755 struct vfio_iommu *iommu = iommu_data; 1756 1757 /* clear known events */ 1758 *events &= ~VFIO_IOMMU_NOTIFY_DMA_UNMAP; 1759 1760 /* refuse to register if still events remaining */ 1761 if (*events) 1762 return -EINVAL; 1763 1764 return blocking_notifier_chain_register(&iommu->notifier, nb); 1765 } 1766 1767 static int vfio_iommu_type1_unregister_notifier(void *iommu_data, 1768 struct notifier_block *nb) 1769 { 1770 struct vfio_iommu *iommu = iommu_data; 1771 1772 return blocking_notifier_chain_unregister(&iommu->notifier, nb); 1773 } 1774 1775 static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1 = { 1776 .name = "vfio-iommu-type1", 1777 .owner = THIS_MODULE, 1778 .open = vfio_iommu_type1_open, 1779 .release = vfio_iommu_type1_release, 1780 .ioctl = vfio_iommu_type1_ioctl, 1781 .attach_group = vfio_iommu_type1_attach_group, 1782 .detach_group = vfio_iommu_type1_detach_group, 1783 .pin_pages = vfio_iommu_type1_pin_pages, 1784 .unpin_pages = vfio_iommu_type1_unpin_pages, 1785 .register_notifier = vfio_iommu_type1_register_notifier, 1786 .unregister_notifier = vfio_iommu_type1_unregister_notifier, 1787 }; 1788 1789 static int __init vfio_iommu_type1_init(void) 1790 { 1791 return vfio_register_iommu_driver(&vfio_iommu_driver_ops_type1); 1792 } 1793 1794 static void __exit vfio_iommu_type1_cleanup(void) 1795 { 1796 vfio_unregister_iommu_driver(&vfio_iommu_driver_ops_type1); 1797 } 1798 1799 module_init(vfio_iommu_type1_init); 1800 module_exit(vfio_iommu_type1_cleanup); 1801 1802 MODULE_VERSION(DRIVER_VERSION); 1803 MODULE_LICENSE("GPL v2"); 1804 MODULE_AUTHOR(DRIVER_AUTHOR); 1805 MODULE_DESCRIPTION(DRIVER_DESC); 1806