2 * VFIO: IOMMU DMA mapping support for Type1 IOMMU
4 * Copyright (C) 2012 Red Hat, Inc. All rights reserved.
5 * Author: Alex Williamson <alex.williamson@redhat.com>
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.
11 * Derived from original vfio:
12 * Copyright 2010 Cisco Systems, Inc. All rights reserved.
13 * Author: Tom Lyon, pugs@cisco.com
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.
27 #include <linux/compat.h>
28 #include <linux/device.h>
30 #include <linux/iommu.h>
31 #include <linux/module.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>
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"
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.");
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.");
62 struct list_head domain_list;
63 struct vfio_domain *external_domain; /* domain for external user */
65 struct rb_root dma_list;
66 struct blocking_notifier_head notifier;
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 */
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 */
86 struct task_struct *task;
87 struct rb_root pfn_list; /* Ex-user pinned pfn list */
91 struct iommu_group *iommu_group;
92 struct list_head next;
96 * Guest RAM pinning working set or DMA target
100 dma_addr_t iova; /* Device address */
101 unsigned long pfn; /* Host pfn */
105 #define IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu) \
106 (!list_empty(&iommu->domain_list))
108 static int put_pfn(unsigned long pfn, int prot);
111 * This code handles mapping and unmapping of user data buffers
112 * into DMA'ble space using the IOMMU
115 static struct vfio_dma *vfio_find_dma(struct vfio_iommu *iommu,
116 dma_addr_t start, size_t size)
118 struct rb_node *node = iommu->dma_list.rb_node;
121 struct vfio_dma *dma = rb_entry(node, struct vfio_dma, node);
123 if (start + size <= dma->iova)
124 node = node->rb_left;
125 else if (start >= dma->iova + dma->size)
126 node = node->rb_right;
134 static void vfio_link_dma(struct vfio_iommu *iommu, struct vfio_dma *new)
136 struct rb_node **link = &iommu->dma_list.rb_node, *parent = NULL;
137 struct vfio_dma *dma;
141 dma = rb_entry(parent, struct vfio_dma, node);
143 if (new->iova + new->size <= dma->iova)
144 link = &(*link)->rb_left;
146 link = &(*link)->rb_right;
149 rb_link_node(&new->node, parent, link);
150 rb_insert_color(&new->node, &iommu->dma_list);
153 static void vfio_unlink_dma(struct vfio_iommu *iommu, struct vfio_dma *old)
155 rb_erase(&old->node, &iommu->dma_list);
159 * Helper Functions for host iova-pfn list
161 static struct vfio_pfn *vfio_find_vpfn(struct vfio_dma *dma, dma_addr_t iova)
163 struct vfio_pfn *vpfn;
164 struct rb_node *node = dma->pfn_list.rb_node;
167 vpfn = rb_entry(node, struct vfio_pfn, node);
169 if (iova < vpfn->iova)
170 node = node->rb_left;
171 else if (iova > vpfn->iova)
172 node = node->rb_right;
179 static void vfio_link_pfn(struct vfio_dma *dma,
180 struct vfio_pfn *new)
182 struct rb_node **link, *parent = NULL;
183 struct vfio_pfn *vpfn;
185 link = &dma->pfn_list.rb_node;
188 vpfn = rb_entry(parent, struct vfio_pfn, node);
190 if (new->iova < vpfn->iova)
191 link = &(*link)->rb_left;
193 link = &(*link)->rb_right;
196 rb_link_node(&new->node, parent, link);
197 rb_insert_color(&new->node, &dma->pfn_list);
200 static void vfio_unlink_pfn(struct vfio_dma *dma, struct vfio_pfn *old)
202 rb_erase(&old->node, &dma->pfn_list);
205 static int vfio_add_to_pfn_list(struct vfio_dma *dma, dma_addr_t iova,
208 struct vfio_pfn *vpfn;
210 vpfn = kzalloc(sizeof(*vpfn), GFP_KERNEL);
216 atomic_set(&vpfn->ref_count, 1);
217 vfio_link_pfn(dma, vpfn);
221 static void vfio_remove_from_pfn_list(struct vfio_dma *dma,
222 struct vfio_pfn *vpfn)
224 vfio_unlink_pfn(dma, vpfn);
228 static struct vfio_pfn *vfio_iova_get_vfio_pfn(struct vfio_dma *dma,
231 struct vfio_pfn *vpfn = vfio_find_vpfn(dma, iova);
234 atomic_inc(&vpfn->ref_count);
238 static int vfio_iova_put_vfio_pfn(struct vfio_dma *dma, struct vfio_pfn *vpfn)
242 if (atomic_dec_and_test(&vpfn->ref_count)) {
243 ret = put_pfn(vpfn->pfn, dma->prot);
244 vfio_remove_from_pfn_list(dma, vpfn);
249 static int vfio_lock_acct(struct task_struct *task, long npage, bool *lock_cap)
251 struct mm_struct *mm;
258 is_current = (task->mm == current->mm);
260 mm = is_current ? task->mm : get_task_mm(task);
262 return -ESRCH; /* process exited */
264 ret = down_write_killable(&mm->mmap_sem);
267 if (lock_cap ? !*lock_cap :
268 !has_capability(task, CAP_IPC_LOCK)) {
271 limit = task_rlimit(task,
272 RLIMIT_MEMLOCK) >> PAGE_SHIFT;
274 if (mm->locked_vm + npage > limit)
280 mm->locked_vm += npage;
282 up_write(&mm->mmap_sem);
292 * Some mappings aren't backed by a struct page, for example an mmap'd
293 * MMIO range for our own or another device. These use a different
294 * pfn conversion and shouldn't be tracked as locked pages.
296 static bool is_invalid_reserved_pfn(unsigned long pfn)
298 if (pfn_valid(pfn)) {
300 struct page *tail = pfn_to_page(pfn);
301 struct page *head = compound_head(tail);
302 reserved = !!(PageReserved(head));
305 * "head" is not a dangling pointer
306 * (compound_head takes care of that)
307 * but the hugepage may have been split
308 * from under us (and we may not hold a
309 * reference count on the head page so it can
310 * be reused before we run PageReferenced), so
311 * we've to check PageTail before returning
318 return PageReserved(tail);
324 static int put_pfn(unsigned long pfn, int prot)
326 if (!is_invalid_reserved_pfn(pfn)) {
327 struct page *page = pfn_to_page(pfn);
328 if (prot & IOMMU_WRITE)
336 static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
337 int prot, unsigned long *pfn)
339 struct page *page[1];
340 struct vm_area_struct *vma;
343 if (mm == current->mm) {
344 ret = get_user_pages_fast(vaddr, 1, !!(prot & IOMMU_WRITE),
347 unsigned int flags = 0;
349 if (prot & IOMMU_WRITE)
352 down_read(&mm->mmap_sem);
353 ret = get_user_pages_remote(NULL, mm, vaddr, 1, flags, page,
355 up_read(&mm->mmap_sem);
359 *pfn = page_to_pfn(page[0]);
363 down_read(&mm->mmap_sem);
365 vma = find_vma_intersection(mm, vaddr, vaddr + 1);
367 if (vma && vma->vm_flags & VM_PFNMAP) {
368 *pfn = ((vaddr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
369 if (is_invalid_reserved_pfn(*pfn))
373 up_read(&mm->mmap_sem);
378 * Attempt to pin pages. We really don't want to track all the pfns and
379 * the iommu can only map chunks of consecutive pfns anyway, so get the
380 * first page and all consecutive pages with the same locking.
382 static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
383 long npage, unsigned long *pfn_base,
384 bool lock_cap, unsigned long limit)
386 unsigned long pfn = 0;
387 long ret, pinned = 0, lock_acct = 0;
389 dma_addr_t iova = vaddr - dma->vaddr + dma->iova;
391 /* This code path is only user initiated */
395 ret = vaddr_get_pfn(current->mm, vaddr, dma->prot, pfn_base);
400 rsvd = is_invalid_reserved_pfn(*pfn_base);
403 * Reserved pages aren't counted against the user, externally pinned
404 * pages are already counted against the user.
406 if (!rsvd && !vfio_find_vpfn(dma, iova)) {
407 if (!lock_cap && current->mm->locked_vm + 1 > limit) {
408 put_pfn(*pfn_base, dma->prot);
409 pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n", __func__,
410 limit << PAGE_SHIFT);
416 if (unlikely(disable_hugepages))
419 /* Lock all the consecutive pages from pfn_base */
420 for (vaddr += PAGE_SIZE, iova += PAGE_SIZE; pinned < npage;
421 pinned++, vaddr += PAGE_SIZE, iova += PAGE_SIZE) {
422 ret = vaddr_get_pfn(current->mm, vaddr, dma->prot, &pfn);
426 if (pfn != *pfn_base + pinned ||
427 rsvd != is_invalid_reserved_pfn(pfn)) {
428 put_pfn(pfn, dma->prot);
432 if (!rsvd && !vfio_find_vpfn(dma, iova)) {
434 current->mm->locked_vm + lock_acct + 1 > limit) {
435 put_pfn(pfn, dma->prot);
436 pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n",
437 __func__, limit << PAGE_SHIFT);
446 ret = vfio_lock_acct(current, lock_acct, &lock_cap);
451 for (pfn = *pfn_base ; pinned ; pfn++, pinned--)
452 put_pfn(pfn, dma->prot);
461 static long vfio_unpin_pages_remote(struct vfio_dma *dma, dma_addr_t iova,
462 unsigned long pfn, long npage,
465 long unlocked = 0, locked = 0;
468 for (i = 0; i < npage; i++, iova += PAGE_SIZE) {
469 if (put_pfn(pfn++, dma->prot)) {
471 if (vfio_find_vpfn(dma, iova))
477 vfio_lock_acct(dma->task, locked - unlocked, NULL);
482 static int vfio_pin_page_external(struct vfio_dma *dma, unsigned long vaddr,
483 unsigned long *pfn_base, bool do_accounting)
485 struct mm_struct *mm;
488 mm = get_task_mm(dma->task);
492 ret = vaddr_get_pfn(mm, vaddr, dma->prot, pfn_base);
493 if (!ret && do_accounting && !is_invalid_reserved_pfn(*pfn_base)) {
494 ret = vfio_lock_acct(dma->task, 1, NULL);
496 put_pfn(*pfn_base, dma->prot);
498 pr_warn("%s: Task %s (%d) RLIMIT_MEMLOCK "
499 "(%ld) exceeded\n", __func__,
500 dma->task->comm, task_pid_nr(dma->task),
501 task_rlimit(dma->task, RLIMIT_MEMLOCK));
509 static int vfio_unpin_page_external(struct vfio_dma *dma, dma_addr_t iova,
513 struct vfio_pfn *vpfn = vfio_find_vpfn(dma, iova);
518 unlocked = vfio_iova_put_vfio_pfn(dma, vpfn);
521 vfio_lock_acct(dma->task, -unlocked, NULL);
526 static int vfio_iommu_type1_pin_pages(void *iommu_data,
527 unsigned long *user_pfn,
529 unsigned long *phys_pfn)
531 struct vfio_iommu *iommu = iommu_data;
533 unsigned long remote_vaddr;
534 struct vfio_dma *dma;
537 if (!iommu || !user_pfn || !phys_pfn)
540 /* Supported for v2 version only */
544 mutex_lock(&iommu->lock);
546 /* Fail if notifier list is empty */
547 if ((!iommu->external_domain) || (!iommu->notifier.head)) {
553 * If iommu capable domain exist in the container then all pages are
554 * already pinned and accounted. Accouting should be done if there is no
555 * iommu capable domain in the container.
557 do_accounting = !IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu);
559 for (i = 0; i < npage; i++) {
561 struct vfio_pfn *vpfn;
563 iova = user_pfn[i] << PAGE_SHIFT;
564 dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
570 if ((dma->prot & prot) != prot) {
575 vpfn = vfio_iova_get_vfio_pfn(dma, iova);
577 phys_pfn[i] = vpfn->pfn;
581 remote_vaddr = dma->vaddr + iova - dma->iova;
582 ret = vfio_pin_page_external(dma, remote_vaddr, &phys_pfn[i],
587 ret = vfio_add_to_pfn_list(dma, iova, phys_pfn[i]);
589 vfio_unpin_page_external(dma, iova, do_accounting);
599 for (j = 0; j < i; j++) {
602 iova = user_pfn[j] << PAGE_SHIFT;
603 dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
604 vfio_unpin_page_external(dma, iova, do_accounting);
608 mutex_unlock(&iommu->lock);
612 static int vfio_iommu_type1_unpin_pages(void *iommu_data,
613 unsigned long *user_pfn,
616 struct vfio_iommu *iommu = iommu_data;
620 if (!iommu || !user_pfn)
623 /* Supported for v2 version only */
627 mutex_lock(&iommu->lock);
629 if (!iommu->external_domain) {
630 mutex_unlock(&iommu->lock);
634 do_accounting = !IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu);
635 for (i = 0; i < npage; i++) {
636 struct vfio_dma *dma;
639 iova = user_pfn[i] << PAGE_SHIFT;
640 dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
643 vfio_unpin_page_external(dma, iova, do_accounting);
647 mutex_unlock(&iommu->lock);
648 return i > npage ? npage : (i > 0 ? i : -EINVAL);
651 static long vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma,
654 dma_addr_t iova = dma->iova, end = dma->iova + dma->size;
655 struct vfio_domain *domain, *d;
661 if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu))
665 * We use the IOMMU to track the physical addresses, otherwise we'd
666 * need a much more complicated tracking system. Unfortunately that
667 * means we need to use one of the iommu domains to figure out the
668 * pfns to unpin. The rest need to be unmapped in advance so we have
669 * no iommu translations remaining when the pages are unpinned.
671 domain = d = list_first_entry(&iommu->domain_list,
672 struct vfio_domain, next);
674 list_for_each_entry_continue(d, &iommu->domain_list, next) {
675 iommu_unmap(d->domain, dma->iova, dma->size);
680 size_t unmapped, len;
681 phys_addr_t phys, next;
683 phys = iommu_iova_to_phys(domain->domain, iova);
684 if (WARN_ON(!phys)) {
690 * To optimize for fewer iommu_unmap() calls, each of which
691 * may require hardware cache flushing, try to find the
692 * largest contiguous physical memory chunk to unmap.
694 for (len = PAGE_SIZE;
695 !domain->fgsp && iova + len < end; len += PAGE_SIZE) {
696 next = iommu_iova_to_phys(domain->domain, iova + len);
697 if (next != phys + len)
701 unmapped = iommu_unmap(domain->domain, iova, len);
702 if (WARN_ON(!unmapped))
705 unlocked += vfio_unpin_pages_remote(dma, iova,
707 unmapped >> PAGE_SHIFT,
714 dma->iommu_mapped = false;
716 vfio_lock_acct(dma->task, -unlocked, NULL);
722 static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
724 vfio_unmap_unpin(iommu, dma, true);
725 vfio_unlink_dma(iommu, dma);
726 put_task_struct(dma->task);
730 static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu)
732 struct vfio_domain *domain;
733 unsigned long bitmap = ULONG_MAX;
735 mutex_lock(&iommu->lock);
736 list_for_each_entry(domain, &iommu->domain_list, next)
737 bitmap &= domain->domain->pgsize_bitmap;
738 mutex_unlock(&iommu->lock);
741 * In case the IOMMU supports page sizes smaller than PAGE_SIZE
742 * we pretend PAGE_SIZE is supported and hide sub-PAGE_SIZE sizes.
743 * That way the user will be able to map/unmap buffers whose size/
744 * start address is aligned with PAGE_SIZE. Pinning code uses that
745 * granularity while iommu driver can use the sub-PAGE_SIZE size
748 if (bitmap & ~PAGE_MASK) {
756 static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
757 struct vfio_iommu_type1_dma_unmap *unmap)
760 struct vfio_dma *dma, *dma_last = NULL;
762 int ret = 0, retries = 0;
764 mask = ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1;
766 if (unmap->iova & mask)
768 if (!unmap->size || unmap->size & mask)
770 if (unmap->iova + unmap->size < unmap->iova ||
771 unmap->size > SIZE_MAX)
774 WARN_ON(mask & PAGE_MASK);
776 mutex_lock(&iommu->lock);
779 * vfio-iommu-type1 (v1) - User mappings were coalesced together to
780 * avoid tracking individual mappings. This means that the granularity
781 * of the original mapping was lost and the user was allowed to attempt
782 * to unmap any range. Depending on the contiguousness of physical
783 * memory and page sizes supported by the IOMMU, arbitrary unmaps may
784 * or may not have worked. We only guaranteed unmap granularity
785 * matching the original mapping; even though it was untracked here,
786 * the original mappings are reflected in IOMMU mappings. This
787 * resulted in a couple unusual behaviors. First, if a range is not
788 * able to be unmapped, ex. a set of 4k pages that was mapped as a
789 * 2M hugepage into the IOMMU, the unmap ioctl returns success but with
790 * a zero sized unmap. Also, if an unmap request overlaps the first
791 * address of a hugepage, the IOMMU will unmap the entire hugepage.
792 * This also returns success and the returned unmap size reflects the
793 * actual size unmapped.
795 * We attempt to maintain compatibility with this "v1" interface, but
796 * we take control out of the hands of the IOMMU. Therefore, an unmap
797 * request offset from the beginning of the original mapping will
798 * return success with zero sized unmap. And an unmap request covering
799 * the first iova of mapping will unmap the entire range.
801 * The v2 version of this interface intends to be more deterministic.
802 * Unmap requests must fully cover previous mappings. Multiple
803 * mappings may still be unmaped by specifying large ranges, but there
804 * must not be any previous mappings bisected by the range. An error
805 * will be returned if these conditions are not met. The v2 interface
806 * will only return success and a size of zero if there were no
807 * mappings within the range.
810 dma = vfio_find_dma(iommu, unmap->iova, 1);
811 if (dma && dma->iova != unmap->iova) {
815 dma = vfio_find_dma(iommu, unmap->iova + unmap->size - 1, 0);
816 if (dma && dma->iova + dma->size != unmap->iova + unmap->size) {
822 while ((dma = vfio_find_dma(iommu, unmap->iova, unmap->size))) {
823 if (!iommu->v2 && unmap->iova > dma->iova)
826 * Task with same address space who mapped this iova range is
827 * allowed to unmap the iova range.
829 if (dma->task->mm != current->mm)
832 if (!RB_EMPTY_ROOT(&dma->pfn_list)) {
833 struct vfio_iommu_type1_dma_unmap nb_unmap;
835 if (dma_last == dma) {
836 BUG_ON(++retries > 10);
842 nb_unmap.iova = dma->iova;
843 nb_unmap.size = dma->size;
846 * Notify anyone (mdev vendor drivers) to invalidate and
847 * unmap iovas within the range we're about to unmap.
848 * Vendor drivers MUST unpin pages in response to an
851 mutex_unlock(&iommu->lock);
852 blocking_notifier_call_chain(&iommu->notifier,
853 VFIO_IOMMU_NOTIFY_DMA_UNMAP,
857 unmapped += dma->size;
858 vfio_remove_dma(iommu, dma);
862 mutex_unlock(&iommu->lock);
864 /* Report how much was unmapped */
865 unmap->size = unmapped;
871 * Turns out AMD IOMMU has a page table bug where it won't map large pages
872 * to a region that previously mapped smaller pages. This should be fixed
873 * soon, so this is just a temporary workaround to break mappings down into
874 * PAGE_SIZE. Better to map smaller pages than nothing.
876 static int map_try_harder(struct vfio_domain *domain, dma_addr_t iova,
877 unsigned long pfn, long npage, int prot)
882 for (i = 0; i < npage; i++, pfn++, iova += PAGE_SIZE) {
883 ret = iommu_map(domain->domain, iova,
884 (phys_addr_t)pfn << PAGE_SHIFT,
885 PAGE_SIZE, prot | domain->prot);
890 for (; i < npage && i > 0; i--, iova -= PAGE_SIZE)
891 iommu_unmap(domain->domain, iova, PAGE_SIZE);
896 static int vfio_iommu_map(struct vfio_iommu *iommu, dma_addr_t iova,
897 unsigned long pfn, long npage, int prot)
899 struct vfio_domain *d;
902 list_for_each_entry(d, &iommu->domain_list, next) {
903 ret = iommu_map(d->domain, iova, (phys_addr_t)pfn << PAGE_SHIFT,
904 npage << PAGE_SHIFT, prot | d->prot);
907 map_try_harder(d, iova, pfn, npage, prot))
917 list_for_each_entry_continue_reverse(d, &iommu->domain_list, next)
918 iommu_unmap(d->domain, iova, npage << PAGE_SHIFT);
923 static int vfio_pin_map_dma(struct vfio_iommu *iommu, struct vfio_dma *dma,
926 dma_addr_t iova = dma->iova;
927 unsigned long vaddr = dma->vaddr;
928 size_t size = map_size;
930 unsigned long pfn, limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
931 bool lock_cap = capable(CAP_IPC_LOCK);
935 /* Pin a contiguous chunk of memory */
936 npage = vfio_pin_pages_remote(dma, vaddr + dma->size,
937 size >> PAGE_SHIFT, &pfn,
946 ret = vfio_iommu_map(iommu, iova + dma->size, pfn, npage,
949 vfio_unpin_pages_remote(dma, iova + dma->size, pfn,
954 size -= npage << PAGE_SHIFT;
955 dma->size += npage << PAGE_SHIFT;
958 dma->iommu_mapped = true;
961 vfio_remove_dma(iommu, dma);
966 static int vfio_dma_do_map(struct vfio_iommu *iommu,
967 struct vfio_iommu_type1_dma_map *map)
969 dma_addr_t iova = map->iova;
970 unsigned long vaddr = map->vaddr;
971 size_t size = map->size;
972 int ret = 0, prot = 0;
974 struct vfio_dma *dma;
976 /* Verify that none of our __u64 fields overflow */
977 if (map->size != size || map->vaddr != vaddr || map->iova != iova)
980 mask = ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1;
982 WARN_ON(mask & PAGE_MASK);
984 /* READ/WRITE from device perspective */
985 if (map->flags & VFIO_DMA_MAP_FLAG_WRITE)
987 if (map->flags & VFIO_DMA_MAP_FLAG_READ)
990 if (!prot || !size || (size | iova | vaddr) & mask)
993 /* Don't allow IOVA or virtual address wrap */
994 if (iova + size - 1 < iova || vaddr + size - 1 < vaddr)
997 mutex_lock(&iommu->lock);
999 if (vfio_find_dma(iommu, iova, size)) {
1004 dma = kzalloc(sizeof(*dma), GFP_KERNEL);
1013 get_task_struct(current);
1014 dma->task = current;
1015 dma->pfn_list = RB_ROOT;
1017 /* Insert zero-sized and grow as we map chunks of it */
1018 vfio_link_dma(iommu, dma);
1020 /* Don't pin and map if container doesn't contain IOMMU capable domain*/
1021 if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu))
1024 ret = vfio_pin_map_dma(iommu, dma, size);
1027 mutex_unlock(&iommu->lock);
1031 static int vfio_bus_type(struct device *dev, void *data)
1033 struct bus_type **bus = data;
1035 if (*bus && *bus != dev->bus)
1043 static int vfio_iommu_replay(struct vfio_iommu *iommu,
1044 struct vfio_domain *domain)
1046 struct vfio_domain *d;
1048 unsigned long limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
1049 bool lock_cap = capable(CAP_IPC_LOCK);
1052 /* Arbitrarily pick the first domain in the list for lookups */
1053 d = list_first_entry(&iommu->domain_list, struct vfio_domain, next);
1054 n = rb_first(&iommu->dma_list);
1056 for (; n; n = rb_next(n)) {
1057 struct vfio_dma *dma;
1060 dma = rb_entry(n, struct vfio_dma, node);
1063 while (iova < dma->iova + dma->size) {
1067 if (dma->iommu_mapped) {
1071 phys = iommu_iova_to_phys(d->domain, iova);
1073 if (WARN_ON(!phys)) {
1081 while (i < dma->iova + dma->size &&
1082 p == iommu_iova_to_phys(d->domain, i)) {
1089 unsigned long vaddr = dma->vaddr +
1091 size_t n = dma->iova + dma->size - iova;
1094 npage = vfio_pin_pages_remote(dma, vaddr,
1104 phys = pfn << PAGE_SHIFT;
1105 size = npage << PAGE_SHIFT;
1108 ret = iommu_map(domain->domain, iova, phys,
1109 size, dma->prot | domain->prot);
1115 dma->iommu_mapped = true;
1121 * We change our unmap behavior slightly depending on whether the IOMMU
1122 * supports fine-grained superpages. IOMMUs like AMD-Vi will use a superpage
1123 * for practically any contiguous power-of-two mapping we give it. This means
1124 * we don't need to look for contiguous chunks ourselves to make unmapping
1125 * more efficient. On IOMMUs with coarse-grained super pages, like Intel VT-d
1126 * with discrete 2M/1G/512G/1T superpages, identifying contiguous chunks
1127 * significantly boosts non-hugetlbfs mappings and doesn't seem to hurt when
1128 * hugetlbfs is in use.
1130 static void vfio_test_domain_fgsp(struct vfio_domain *domain)
1133 int ret, order = get_order(PAGE_SIZE * 2);
1135 pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
1139 ret = iommu_map(domain->domain, 0, page_to_phys(pages), PAGE_SIZE * 2,
1140 IOMMU_READ | IOMMU_WRITE | domain->prot);
1142 size_t unmapped = iommu_unmap(domain->domain, 0, PAGE_SIZE);
1144 if (unmapped == PAGE_SIZE)
1145 iommu_unmap(domain->domain, PAGE_SIZE, PAGE_SIZE);
1147 domain->fgsp = true;
1150 __free_pages(pages, order);
1153 static struct vfio_group *find_iommu_group(struct vfio_domain *domain,
1154 struct iommu_group *iommu_group)
1156 struct vfio_group *g;
1158 list_for_each_entry(g, &domain->group_list, next) {
1159 if (g->iommu_group == iommu_group)
1166 static bool vfio_iommu_has_sw_msi(struct iommu_group *group, phys_addr_t *base)
1168 struct list_head group_resv_regions;
1169 struct iommu_resv_region *region, *next;
1172 INIT_LIST_HEAD(&group_resv_regions);
1173 iommu_get_group_resv_regions(group, &group_resv_regions);
1174 list_for_each_entry(region, &group_resv_regions, list) {
1176 * The presence of any 'real' MSI regions should take
1177 * precedence over the software-managed one if the
1178 * IOMMU driver happens to advertise both types.
1180 if (region->type == IOMMU_RESV_MSI) {
1185 if (region->type == IOMMU_RESV_SW_MSI) {
1186 *base = region->start;
1190 list_for_each_entry_safe(region, next, &group_resv_regions, list)
1195 static int vfio_iommu_type1_attach_group(void *iommu_data,
1196 struct iommu_group *iommu_group)
1198 struct vfio_iommu *iommu = iommu_data;
1199 struct vfio_group *group;
1200 struct vfio_domain *domain, *d;
1201 struct bus_type *bus = NULL, *mdev_bus;
1203 bool resv_msi, msi_remap;
1204 phys_addr_t resv_msi_base;
1206 mutex_lock(&iommu->lock);
1208 list_for_each_entry(d, &iommu->domain_list, next) {
1209 if (find_iommu_group(d, iommu_group)) {
1210 mutex_unlock(&iommu->lock);
1215 if (iommu->external_domain) {
1216 if (find_iommu_group(iommu->external_domain, iommu_group)) {
1217 mutex_unlock(&iommu->lock);
1222 group = kzalloc(sizeof(*group), GFP_KERNEL);
1223 domain = kzalloc(sizeof(*domain), GFP_KERNEL);
1224 if (!group || !domain) {
1229 group->iommu_group = iommu_group;
1231 /* Determine bus_type in order to allocate a domain */
1232 ret = iommu_group_for_each_dev(iommu_group, &bus, vfio_bus_type);
1236 mdev_bus = symbol_get(mdev_bus_type);
1239 if ((bus == mdev_bus) && !iommu_present(bus)) {
1240 symbol_put(mdev_bus_type);
1241 if (!iommu->external_domain) {
1242 INIT_LIST_HEAD(&domain->group_list);
1243 iommu->external_domain = domain;
1247 list_add(&group->next,
1248 &iommu->external_domain->group_list);
1249 mutex_unlock(&iommu->lock);
1252 symbol_put(mdev_bus_type);
1255 domain->domain = iommu_domain_alloc(bus);
1256 if (!domain->domain) {
1261 if (iommu->nesting) {
1264 ret = iommu_domain_set_attr(domain->domain, DOMAIN_ATTR_NESTING,
1270 ret = iommu_attach_group(domain->domain, iommu_group);
1274 resv_msi = vfio_iommu_has_sw_msi(iommu_group, &resv_msi_base);
1276 INIT_LIST_HEAD(&domain->group_list);
1277 list_add(&group->next, &domain->group_list);
1279 msi_remap = irq_domain_check_msi_remap() ||
1280 iommu_capable(bus, IOMMU_CAP_INTR_REMAP);
1282 if (!allow_unsafe_interrupts && !msi_remap) {
1283 pr_warn("%s: No interrupt remapping support. Use the module param \"allow_unsafe_interrupts\" to enable VFIO IOMMU support on this platform\n",
1289 if (iommu_capable(bus, IOMMU_CAP_CACHE_COHERENCY))
1290 domain->prot |= IOMMU_CACHE;
1293 * Try to match an existing compatible domain. We don't want to
1294 * preclude an IOMMU driver supporting multiple bus_types and being
1295 * able to include different bus_types in the same IOMMU domain, so
1296 * we test whether the domains use the same iommu_ops rather than
1297 * testing if they're on the same bus_type.
1299 list_for_each_entry(d, &iommu->domain_list, next) {
1300 if (d->domain->ops == domain->domain->ops &&
1301 d->prot == domain->prot) {
1302 iommu_detach_group(domain->domain, iommu_group);
1303 if (!iommu_attach_group(d->domain, iommu_group)) {
1304 list_add(&group->next, &d->group_list);
1305 iommu_domain_free(domain->domain);
1307 mutex_unlock(&iommu->lock);
1311 ret = iommu_attach_group(domain->domain, iommu_group);
1317 vfio_test_domain_fgsp(domain);
1319 /* replay mappings on new domains */
1320 ret = vfio_iommu_replay(iommu, domain);
1325 ret = iommu_get_msi_cookie(domain->domain, resv_msi_base);
1330 list_add(&domain->next, &iommu->domain_list);
1332 mutex_unlock(&iommu->lock);
1337 iommu_detach_group(domain->domain, iommu_group);
1339 iommu_domain_free(domain->domain);
1343 mutex_unlock(&iommu->lock);
1347 static void vfio_iommu_unmap_unpin_all(struct vfio_iommu *iommu)
1349 struct rb_node *node;
1351 while ((node = rb_first(&iommu->dma_list)))
1352 vfio_remove_dma(iommu, rb_entry(node, struct vfio_dma, node));
1355 static void vfio_iommu_unmap_unpin_reaccount(struct vfio_iommu *iommu)
1357 struct rb_node *n, *p;
1359 n = rb_first(&iommu->dma_list);
1360 for (; n; n = rb_next(n)) {
1361 struct vfio_dma *dma;
1362 long locked = 0, unlocked = 0;
1364 dma = rb_entry(n, struct vfio_dma, node);
1365 unlocked += vfio_unmap_unpin(iommu, dma, false);
1366 p = rb_first(&dma->pfn_list);
1367 for (; p; p = rb_next(p)) {
1368 struct vfio_pfn *vpfn = rb_entry(p, struct vfio_pfn,
1371 if (!is_invalid_reserved_pfn(vpfn->pfn))
1374 vfio_lock_acct(dma->task, locked - unlocked, NULL);
1378 static void vfio_sanity_check_pfn_list(struct vfio_iommu *iommu)
1382 n = rb_first(&iommu->dma_list);
1383 for (; n; n = rb_next(n)) {
1384 struct vfio_dma *dma;
1386 dma = rb_entry(n, struct vfio_dma, node);
1388 if (WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list)))
1391 /* mdev vendor driver must unregister notifier */
1392 WARN_ON(iommu->notifier.head);
1395 static void vfio_iommu_type1_detach_group(void *iommu_data,
1396 struct iommu_group *iommu_group)
1398 struct vfio_iommu *iommu = iommu_data;
1399 struct vfio_domain *domain;
1400 struct vfio_group *group;
1402 mutex_lock(&iommu->lock);
1404 if (iommu->external_domain) {
1405 group = find_iommu_group(iommu->external_domain, iommu_group);
1407 list_del(&group->next);
1410 if (list_empty(&iommu->external_domain->group_list)) {
1411 vfio_sanity_check_pfn_list(iommu);
1413 if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu))
1414 vfio_iommu_unmap_unpin_all(iommu);
1416 kfree(iommu->external_domain);
1417 iommu->external_domain = NULL;
1419 goto detach_group_done;
1423 list_for_each_entry(domain, &iommu->domain_list, next) {
1424 group = find_iommu_group(domain, iommu_group);
1428 iommu_detach_group(domain->domain, iommu_group);
1429 list_del(&group->next);
1432 * Group ownership provides privilege, if the group list is
1433 * empty, the domain goes away. If it's the last domain with
1434 * iommu and external domain doesn't exist, then all the
1435 * mappings go away too. If it's the last domain with iommu and
1436 * external domain exist, update accounting
1438 if (list_empty(&domain->group_list)) {
1439 if (list_is_singular(&iommu->domain_list)) {
1440 if (!iommu->external_domain)
1441 vfio_iommu_unmap_unpin_all(iommu);
1443 vfio_iommu_unmap_unpin_reaccount(iommu);
1445 iommu_domain_free(domain->domain);
1446 list_del(&domain->next);
1453 mutex_unlock(&iommu->lock);
1456 static void *vfio_iommu_type1_open(unsigned long arg)
1458 struct vfio_iommu *iommu;
1460 iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
1462 return ERR_PTR(-ENOMEM);
1465 case VFIO_TYPE1_IOMMU:
1467 case VFIO_TYPE1_NESTING_IOMMU:
1468 iommu->nesting = true;
1469 case VFIO_TYPE1v2_IOMMU:
1474 return ERR_PTR(-EINVAL);
1477 INIT_LIST_HEAD(&iommu->domain_list);
1478 iommu->dma_list = RB_ROOT;
1479 mutex_init(&iommu->lock);
1480 BLOCKING_INIT_NOTIFIER_HEAD(&iommu->notifier);
1485 static void vfio_release_domain(struct vfio_domain *domain, bool external)
1487 struct vfio_group *group, *group_tmp;
1489 list_for_each_entry_safe(group, group_tmp,
1490 &domain->group_list, next) {
1492 iommu_detach_group(domain->domain, group->iommu_group);
1493 list_del(&group->next);
1498 iommu_domain_free(domain->domain);
1501 static void vfio_iommu_type1_release(void *iommu_data)
1503 struct vfio_iommu *iommu = iommu_data;
1504 struct vfio_domain *domain, *domain_tmp;
1506 if (iommu->external_domain) {
1507 vfio_release_domain(iommu->external_domain, true);
1508 vfio_sanity_check_pfn_list(iommu);
1509 kfree(iommu->external_domain);
1512 vfio_iommu_unmap_unpin_all(iommu);
1514 list_for_each_entry_safe(domain, domain_tmp,
1515 &iommu->domain_list, next) {
1516 vfio_release_domain(domain, false);
1517 list_del(&domain->next);
1523 static int vfio_domains_have_iommu_cache(struct vfio_iommu *iommu)
1525 struct vfio_domain *domain;
1528 mutex_lock(&iommu->lock);
1529 list_for_each_entry(domain, &iommu->domain_list, next) {
1530 if (!(domain->prot & IOMMU_CACHE)) {
1535 mutex_unlock(&iommu->lock);
1540 static long vfio_iommu_type1_ioctl(void *iommu_data,
1541 unsigned int cmd, unsigned long arg)
1543 struct vfio_iommu *iommu = iommu_data;
1544 unsigned long minsz;
1546 if (cmd == VFIO_CHECK_EXTENSION) {
1548 case VFIO_TYPE1_IOMMU:
1549 case VFIO_TYPE1v2_IOMMU:
1550 case VFIO_TYPE1_NESTING_IOMMU:
1552 case VFIO_DMA_CC_IOMMU:
1555 return vfio_domains_have_iommu_cache(iommu);
1559 } else if (cmd == VFIO_IOMMU_GET_INFO) {
1560 struct vfio_iommu_type1_info info;
1562 minsz = offsetofend(struct vfio_iommu_type1_info, iova_pgsizes);
1564 if (copy_from_user(&info, (void __user *)arg, minsz))
1567 if (info.argsz < minsz)
1570 info.flags = VFIO_IOMMU_INFO_PGSIZES;
1572 info.iova_pgsizes = vfio_pgsize_bitmap(iommu);
1574 return copy_to_user((void __user *)arg, &info, minsz) ?
1577 } else if (cmd == VFIO_IOMMU_MAP_DMA) {
1578 struct vfio_iommu_type1_dma_map map;
1579 uint32_t mask = VFIO_DMA_MAP_FLAG_READ |
1580 VFIO_DMA_MAP_FLAG_WRITE;
1582 minsz = offsetofend(struct vfio_iommu_type1_dma_map, size);
1584 if (copy_from_user(&map, (void __user *)arg, minsz))
1587 if (map.argsz < minsz || map.flags & ~mask)
1590 return vfio_dma_do_map(iommu, &map);
1592 } else if (cmd == VFIO_IOMMU_UNMAP_DMA) {
1593 struct vfio_iommu_type1_dma_unmap unmap;
1596 minsz = offsetofend(struct vfio_iommu_type1_dma_unmap, size);
1598 if (copy_from_user(&unmap, (void __user *)arg, minsz))
1601 if (unmap.argsz < minsz || unmap.flags)
1604 ret = vfio_dma_do_unmap(iommu, &unmap);
1608 return copy_to_user((void __user *)arg, &unmap, minsz) ?
1615 static int vfio_iommu_type1_register_notifier(void *iommu_data,
1616 unsigned long *events,
1617 struct notifier_block *nb)
1619 struct vfio_iommu *iommu = iommu_data;
1621 /* clear known events */
1622 *events &= ~VFIO_IOMMU_NOTIFY_DMA_UNMAP;
1624 /* refuse to register if still events remaining */
1628 return blocking_notifier_chain_register(&iommu->notifier, nb);
1631 static int vfio_iommu_type1_unregister_notifier(void *iommu_data,
1632 struct notifier_block *nb)
1634 struct vfio_iommu *iommu = iommu_data;
1636 return blocking_notifier_chain_unregister(&iommu->notifier, nb);
1639 static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1 = {
1640 .name = "vfio-iommu-type1",
1641 .owner = THIS_MODULE,
1642 .open = vfio_iommu_type1_open,
1643 .release = vfio_iommu_type1_release,
1644 .ioctl = vfio_iommu_type1_ioctl,
1645 .attach_group = vfio_iommu_type1_attach_group,
1646 .detach_group = vfio_iommu_type1_detach_group,
1647 .pin_pages = vfio_iommu_type1_pin_pages,
1648 .unpin_pages = vfio_iommu_type1_unpin_pages,
1649 .register_notifier = vfio_iommu_type1_register_notifier,
1650 .unregister_notifier = vfio_iommu_type1_unregister_notifier,
1653 static int __init vfio_iommu_type1_init(void)
1655 return vfio_register_iommu_driver(&vfio_iommu_driver_ops_type1);
1658 static void __exit vfio_iommu_type1_cleanup(void)
1660 vfio_unregister_iommu_driver(&vfio_iommu_driver_ops_type1);
1663 module_init(vfio_iommu_type1_init);
1664 module_exit(vfio_iommu_type1_cleanup);
1666 MODULE_VERSION(DRIVER_VERSION);
1667 MODULE_LICENSE("GPL v2");
1668 MODULE_AUTHOR(DRIVER_AUTHOR);
1669 MODULE_DESCRIPTION(DRIVER_DESC);