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)
771 WARN_ON(mask & PAGE_MASK);
773 mutex_lock(&iommu->lock);
776 * vfio-iommu-type1 (v1) - User mappings were coalesced together to
777 * avoid tracking individual mappings. This means that the granularity
778 * of the original mapping was lost and the user was allowed to attempt
779 * to unmap any range. Depending on the contiguousness of physical
780 * memory and page sizes supported by the IOMMU, arbitrary unmaps may
781 * or may not have worked. We only guaranteed unmap granularity
782 * matching the original mapping; even though it was untracked here,
783 * the original mappings are reflected in IOMMU mappings. This
784 * resulted in a couple unusual behaviors. First, if a range is not
785 * able to be unmapped, ex. a set of 4k pages that was mapped as a
786 * 2M hugepage into the IOMMU, the unmap ioctl returns success but with
787 * a zero sized unmap. Also, if an unmap request overlaps the first
788 * address of a hugepage, the IOMMU will unmap the entire hugepage.
789 * This also returns success and the returned unmap size reflects the
790 * actual size unmapped.
792 * We attempt to maintain compatibility with this "v1" interface, but
793 * we take control out of the hands of the IOMMU. Therefore, an unmap
794 * request offset from the beginning of the original mapping will
795 * return success with zero sized unmap. And an unmap request covering
796 * the first iova of mapping will unmap the entire range.
798 * The v2 version of this interface intends to be more deterministic.
799 * Unmap requests must fully cover previous mappings. Multiple
800 * mappings may still be unmaped by specifying large ranges, but there
801 * must not be any previous mappings bisected by the range. An error
802 * will be returned if these conditions are not met. The v2 interface
803 * will only return success and a size of zero if there were no
804 * mappings within the range.
807 dma = vfio_find_dma(iommu, unmap->iova, 1);
808 if (dma && dma->iova != unmap->iova) {
812 dma = vfio_find_dma(iommu, unmap->iova + unmap->size - 1, 0);
813 if (dma && dma->iova + dma->size != unmap->iova + unmap->size) {
819 while ((dma = vfio_find_dma(iommu, unmap->iova, unmap->size))) {
820 if (!iommu->v2 && unmap->iova > dma->iova)
823 * Task with same address space who mapped this iova range is
824 * allowed to unmap the iova range.
826 if (dma->task->mm != current->mm)
829 if (!RB_EMPTY_ROOT(&dma->pfn_list)) {
830 struct vfio_iommu_type1_dma_unmap nb_unmap;
832 if (dma_last == dma) {
833 BUG_ON(++retries > 10);
839 nb_unmap.iova = dma->iova;
840 nb_unmap.size = dma->size;
843 * Notify anyone (mdev vendor drivers) to invalidate and
844 * unmap iovas within the range we're about to unmap.
845 * Vendor drivers MUST unpin pages in response to an
848 mutex_unlock(&iommu->lock);
849 blocking_notifier_call_chain(&iommu->notifier,
850 VFIO_IOMMU_NOTIFY_DMA_UNMAP,
854 unmapped += dma->size;
855 vfio_remove_dma(iommu, dma);
859 mutex_unlock(&iommu->lock);
861 /* Report how much was unmapped */
862 unmap->size = unmapped;
868 * Turns out AMD IOMMU has a page table bug where it won't map large pages
869 * to a region that previously mapped smaller pages. This should be fixed
870 * soon, so this is just a temporary workaround to break mappings down into
871 * PAGE_SIZE. Better to map smaller pages than nothing.
873 static int map_try_harder(struct vfio_domain *domain, dma_addr_t iova,
874 unsigned long pfn, long npage, int prot)
879 for (i = 0; i < npage; i++, pfn++, iova += PAGE_SIZE) {
880 ret = iommu_map(domain->domain, iova,
881 (phys_addr_t)pfn << PAGE_SHIFT,
882 PAGE_SIZE, prot | domain->prot);
887 for (; i < npage && i > 0; i--, iova -= PAGE_SIZE)
888 iommu_unmap(domain->domain, iova, PAGE_SIZE);
893 static int vfio_iommu_map(struct vfio_iommu *iommu, dma_addr_t iova,
894 unsigned long pfn, long npage, int prot)
896 struct vfio_domain *d;
899 list_for_each_entry(d, &iommu->domain_list, next) {
900 ret = iommu_map(d->domain, iova, (phys_addr_t)pfn << PAGE_SHIFT,
901 npage << PAGE_SHIFT, prot | d->prot);
904 map_try_harder(d, iova, pfn, npage, prot))
914 list_for_each_entry_continue_reverse(d, &iommu->domain_list, next)
915 iommu_unmap(d->domain, iova, npage << PAGE_SHIFT);
920 static int vfio_pin_map_dma(struct vfio_iommu *iommu, struct vfio_dma *dma,
923 dma_addr_t iova = dma->iova;
924 unsigned long vaddr = dma->vaddr;
925 size_t size = map_size;
927 unsigned long pfn, limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
928 bool lock_cap = capable(CAP_IPC_LOCK);
932 /* Pin a contiguous chunk of memory */
933 npage = vfio_pin_pages_remote(dma, vaddr + dma->size,
934 size >> PAGE_SHIFT, &pfn,
943 ret = vfio_iommu_map(iommu, iova + dma->size, pfn, npage,
946 vfio_unpin_pages_remote(dma, iova + dma->size, pfn,
951 size -= npage << PAGE_SHIFT;
952 dma->size += npage << PAGE_SHIFT;
955 dma->iommu_mapped = true;
958 vfio_remove_dma(iommu, dma);
963 static int vfio_dma_do_map(struct vfio_iommu *iommu,
964 struct vfio_iommu_type1_dma_map *map)
966 dma_addr_t iova = map->iova;
967 unsigned long vaddr = map->vaddr;
968 size_t size = map->size;
969 int ret = 0, prot = 0;
971 struct vfio_dma *dma;
973 /* Verify that none of our __u64 fields overflow */
974 if (map->size != size || map->vaddr != vaddr || map->iova != iova)
977 mask = ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1;
979 WARN_ON(mask & PAGE_MASK);
981 /* READ/WRITE from device perspective */
982 if (map->flags & VFIO_DMA_MAP_FLAG_WRITE)
984 if (map->flags & VFIO_DMA_MAP_FLAG_READ)
987 if (!prot || !size || (size | iova | vaddr) & mask)
990 /* Don't allow IOVA or virtual address wrap */
991 if (iova + size - 1 < iova || vaddr + size - 1 < vaddr)
994 mutex_lock(&iommu->lock);
996 if (vfio_find_dma(iommu, iova, size)) {
1001 dma = kzalloc(sizeof(*dma), GFP_KERNEL);
1010 get_task_struct(current);
1011 dma->task = current;
1012 dma->pfn_list = RB_ROOT;
1014 /* Insert zero-sized and grow as we map chunks of it */
1015 vfio_link_dma(iommu, dma);
1017 /* Don't pin and map if container doesn't contain IOMMU capable domain*/
1018 if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu))
1021 ret = vfio_pin_map_dma(iommu, dma, size);
1024 mutex_unlock(&iommu->lock);
1028 static int vfio_bus_type(struct device *dev, void *data)
1030 struct bus_type **bus = data;
1032 if (*bus && *bus != dev->bus)
1040 static int vfio_iommu_replay(struct vfio_iommu *iommu,
1041 struct vfio_domain *domain)
1043 struct vfio_domain *d;
1045 unsigned long limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
1046 bool lock_cap = capable(CAP_IPC_LOCK);
1049 /* Arbitrarily pick the first domain in the list for lookups */
1050 d = list_first_entry(&iommu->domain_list, struct vfio_domain, next);
1051 n = rb_first(&iommu->dma_list);
1053 for (; n; n = rb_next(n)) {
1054 struct vfio_dma *dma;
1057 dma = rb_entry(n, struct vfio_dma, node);
1060 while (iova < dma->iova + dma->size) {
1064 if (dma->iommu_mapped) {
1068 phys = iommu_iova_to_phys(d->domain, iova);
1070 if (WARN_ON(!phys)) {
1078 while (i < dma->iova + dma->size &&
1079 p == iommu_iova_to_phys(d->domain, i)) {
1086 unsigned long vaddr = dma->vaddr +
1088 size_t n = dma->iova + dma->size - iova;
1091 npage = vfio_pin_pages_remote(dma, vaddr,
1101 phys = pfn << PAGE_SHIFT;
1102 size = npage << PAGE_SHIFT;
1105 ret = iommu_map(domain->domain, iova, phys,
1106 size, dma->prot | domain->prot);
1112 dma->iommu_mapped = true;
1118 * We change our unmap behavior slightly depending on whether the IOMMU
1119 * supports fine-grained superpages. IOMMUs like AMD-Vi will use a superpage
1120 * for practically any contiguous power-of-two mapping we give it. This means
1121 * we don't need to look for contiguous chunks ourselves to make unmapping
1122 * more efficient. On IOMMUs with coarse-grained super pages, like Intel VT-d
1123 * with discrete 2M/1G/512G/1T superpages, identifying contiguous chunks
1124 * significantly boosts non-hugetlbfs mappings and doesn't seem to hurt when
1125 * hugetlbfs is in use.
1127 static void vfio_test_domain_fgsp(struct vfio_domain *domain)
1130 int ret, order = get_order(PAGE_SIZE * 2);
1132 pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
1136 ret = iommu_map(domain->domain, 0, page_to_phys(pages), PAGE_SIZE * 2,
1137 IOMMU_READ | IOMMU_WRITE | domain->prot);
1139 size_t unmapped = iommu_unmap(domain->domain, 0, PAGE_SIZE);
1141 if (unmapped == PAGE_SIZE)
1142 iommu_unmap(domain->domain, PAGE_SIZE, PAGE_SIZE);
1144 domain->fgsp = true;
1147 __free_pages(pages, order);
1150 static struct vfio_group *find_iommu_group(struct vfio_domain *domain,
1151 struct iommu_group *iommu_group)
1153 struct vfio_group *g;
1155 list_for_each_entry(g, &domain->group_list, next) {
1156 if (g->iommu_group == iommu_group)
1163 static bool vfio_iommu_has_sw_msi(struct iommu_group *group, phys_addr_t *base)
1165 struct list_head group_resv_regions;
1166 struct iommu_resv_region *region, *next;
1169 INIT_LIST_HEAD(&group_resv_regions);
1170 iommu_get_group_resv_regions(group, &group_resv_regions);
1171 list_for_each_entry(region, &group_resv_regions, list) {
1172 if (region->type == IOMMU_RESV_SW_MSI) {
1173 *base = region->start;
1179 list_for_each_entry_safe(region, next, &group_resv_regions, list)
1184 static int vfio_iommu_type1_attach_group(void *iommu_data,
1185 struct iommu_group *iommu_group)
1187 struct vfio_iommu *iommu = iommu_data;
1188 struct vfio_group *group;
1189 struct vfio_domain *domain, *d;
1190 struct bus_type *bus = NULL, *mdev_bus;
1192 bool resv_msi, msi_remap;
1193 phys_addr_t resv_msi_base;
1195 mutex_lock(&iommu->lock);
1197 list_for_each_entry(d, &iommu->domain_list, next) {
1198 if (find_iommu_group(d, iommu_group)) {
1199 mutex_unlock(&iommu->lock);
1204 if (iommu->external_domain) {
1205 if (find_iommu_group(iommu->external_domain, iommu_group)) {
1206 mutex_unlock(&iommu->lock);
1211 group = kzalloc(sizeof(*group), GFP_KERNEL);
1212 domain = kzalloc(sizeof(*domain), GFP_KERNEL);
1213 if (!group || !domain) {
1218 group->iommu_group = iommu_group;
1220 /* Determine bus_type in order to allocate a domain */
1221 ret = iommu_group_for_each_dev(iommu_group, &bus, vfio_bus_type);
1225 mdev_bus = symbol_get(mdev_bus_type);
1228 if ((bus == mdev_bus) && !iommu_present(bus)) {
1229 symbol_put(mdev_bus_type);
1230 if (!iommu->external_domain) {
1231 INIT_LIST_HEAD(&domain->group_list);
1232 iommu->external_domain = domain;
1236 list_add(&group->next,
1237 &iommu->external_domain->group_list);
1238 mutex_unlock(&iommu->lock);
1241 symbol_put(mdev_bus_type);
1244 domain->domain = iommu_domain_alloc(bus);
1245 if (!domain->domain) {
1250 if (iommu->nesting) {
1253 ret = iommu_domain_set_attr(domain->domain, DOMAIN_ATTR_NESTING,
1259 ret = iommu_attach_group(domain->domain, iommu_group);
1263 resv_msi = vfio_iommu_has_sw_msi(iommu_group, &resv_msi_base);
1265 INIT_LIST_HEAD(&domain->group_list);
1266 list_add(&group->next, &domain->group_list);
1268 msi_remap = resv_msi ? irq_domain_check_msi_remap() :
1269 iommu_capable(bus, IOMMU_CAP_INTR_REMAP);
1271 if (!allow_unsafe_interrupts && !msi_remap) {
1272 pr_warn("%s: No interrupt remapping support. Use the module param \"allow_unsafe_interrupts\" to enable VFIO IOMMU support on this platform\n",
1278 if (iommu_capable(bus, IOMMU_CAP_CACHE_COHERENCY))
1279 domain->prot |= IOMMU_CACHE;
1282 * Try to match an existing compatible domain. We don't want to
1283 * preclude an IOMMU driver supporting multiple bus_types and being
1284 * able to include different bus_types in the same IOMMU domain, so
1285 * we test whether the domains use the same iommu_ops rather than
1286 * testing if they're on the same bus_type.
1288 list_for_each_entry(d, &iommu->domain_list, next) {
1289 if (d->domain->ops == domain->domain->ops &&
1290 d->prot == domain->prot) {
1291 iommu_detach_group(domain->domain, iommu_group);
1292 if (!iommu_attach_group(d->domain, iommu_group)) {
1293 list_add(&group->next, &d->group_list);
1294 iommu_domain_free(domain->domain);
1296 mutex_unlock(&iommu->lock);
1300 ret = iommu_attach_group(domain->domain, iommu_group);
1306 vfio_test_domain_fgsp(domain);
1308 /* replay mappings on new domains */
1309 ret = vfio_iommu_replay(iommu, domain);
1314 ret = iommu_get_msi_cookie(domain->domain, resv_msi_base);
1319 list_add(&domain->next, &iommu->domain_list);
1321 mutex_unlock(&iommu->lock);
1326 iommu_detach_group(domain->domain, iommu_group);
1328 iommu_domain_free(domain->domain);
1332 mutex_unlock(&iommu->lock);
1336 static void vfio_iommu_unmap_unpin_all(struct vfio_iommu *iommu)
1338 struct rb_node *node;
1340 while ((node = rb_first(&iommu->dma_list)))
1341 vfio_remove_dma(iommu, rb_entry(node, struct vfio_dma, node));
1344 static void vfio_iommu_unmap_unpin_reaccount(struct vfio_iommu *iommu)
1346 struct rb_node *n, *p;
1348 n = rb_first(&iommu->dma_list);
1349 for (; n; n = rb_next(n)) {
1350 struct vfio_dma *dma;
1351 long locked = 0, unlocked = 0;
1353 dma = rb_entry(n, struct vfio_dma, node);
1354 unlocked += vfio_unmap_unpin(iommu, dma, false);
1355 p = rb_first(&dma->pfn_list);
1356 for (; p; p = rb_next(p)) {
1357 struct vfio_pfn *vpfn = rb_entry(p, struct vfio_pfn,
1360 if (!is_invalid_reserved_pfn(vpfn->pfn))
1363 vfio_lock_acct(dma->task, locked - unlocked, NULL);
1367 static void vfio_sanity_check_pfn_list(struct vfio_iommu *iommu)
1371 n = rb_first(&iommu->dma_list);
1372 for (; n; n = rb_next(n)) {
1373 struct vfio_dma *dma;
1375 dma = rb_entry(n, struct vfio_dma, node);
1377 if (WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list)))
1380 /* mdev vendor driver must unregister notifier */
1381 WARN_ON(iommu->notifier.head);
1384 static void vfio_iommu_type1_detach_group(void *iommu_data,
1385 struct iommu_group *iommu_group)
1387 struct vfio_iommu *iommu = iommu_data;
1388 struct vfio_domain *domain;
1389 struct vfio_group *group;
1391 mutex_lock(&iommu->lock);
1393 if (iommu->external_domain) {
1394 group = find_iommu_group(iommu->external_domain, iommu_group);
1396 list_del(&group->next);
1399 if (list_empty(&iommu->external_domain->group_list)) {
1400 vfio_sanity_check_pfn_list(iommu);
1402 if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu))
1403 vfio_iommu_unmap_unpin_all(iommu);
1405 kfree(iommu->external_domain);
1406 iommu->external_domain = NULL;
1408 goto detach_group_done;
1412 list_for_each_entry(domain, &iommu->domain_list, next) {
1413 group = find_iommu_group(domain, iommu_group);
1417 iommu_detach_group(domain->domain, iommu_group);
1418 list_del(&group->next);
1421 * Group ownership provides privilege, if the group list is
1422 * empty, the domain goes away. If it's the last domain with
1423 * iommu and external domain doesn't exist, then all the
1424 * mappings go away too. If it's the last domain with iommu and
1425 * external domain exist, update accounting
1427 if (list_empty(&domain->group_list)) {
1428 if (list_is_singular(&iommu->domain_list)) {
1429 if (!iommu->external_domain)
1430 vfio_iommu_unmap_unpin_all(iommu);
1432 vfio_iommu_unmap_unpin_reaccount(iommu);
1434 iommu_domain_free(domain->domain);
1435 list_del(&domain->next);
1442 mutex_unlock(&iommu->lock);
1445 static void *vfio_iommu_type1_open(unsigned long arg)
1447 struct vfio_iommu *iommu;
1449 iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
1451 return ERR_PTR(-ENOMEM);
1454 case VFIO_TYPE1_IOMMU:
1456 case VFIO_TYPE1_NESTING_IOMMU:
1457 iommu->nesting = true;
1458 case VFIO_TYPE1v2_IOMMU:
1463 return ERR_PTR(-EINVAL);
1466 INIT_LIST_HEAD(&iommu->domain_list);
1467 iommu->dma_list = RB_ROOT;
1468 mutex_init(&iommu->lock);
1469 BLOCKING_INIT_NOTIFIER_HEAD(&iommu->notifier);
1474 static void vfio_release_domain(struct vfio_domain *domain, bool external)
1476 struct vfio_group *group, *group_tmp;
1478 list_for_each_entry_safe(group, group_tmp,
1479 &domain->group_list, next) {
1481 iommu_detach_group(domain->domain, group->iommu_group);
1482 list_del(&group->next);
1487 iommu_domain_free(domain->domain);
1490 static void vfio_iommu_type1_release(void *iommu_data)
1492 struct vfio_iommu *iommu = iommu_data;
1493 struct vfio_domain *domain, *domain_tmp;
1495 if (iommu->external_domain) {
1496 vfio_release_domain(iommu->external_domain, true);
1497 vfio_sanity_check_pfn_list(iommu);
1498 kfree(iommu->external_domain);
1501 vfio_iommu_unmap_unpin_all(iommu);
1503 list_for_each_entry_safe(domain, domain_tmp,
1504 &iommu->domain_list, next) {
1505 vfio_release_domain(domain, false);
1506 list_del(&domain->next);
1512 static int vfio_domains_have_iommu_cache(struct vfio_iommu *iommu)
1514 struct vfio_domain *domain;
1517 mutex_lock(&iommu->lock);
1518 list_for_each_entry(domain, &iommu->domain_list, next) {
1519 if (!(domain->prot & IOMMU_CACHE)) {
1524 mutex_unlock(&iommu->lock);
1529 static long vfio_iommu_type1_ioctl(void *iommu_data,
1530 unsigned int cmd, unsigned long arg)
1532 struct vfio_iommu *iommu = iommu_data;
1533 unsigned long minsz;
1535 if (cmd == VFIO_CHECK_EXTENSION) {
1537 case VFIO_TYPE1_IOMMU:
1538 case VFIO_TYPE1v2_IOMMU:
1539 case VFIO_TYPE1_NESTING_IOMMU:
1541 case VFIO_DMA_CC_IOMMU:
1544 return vfio_domains_have_iommu_cache(iommu);
1548 } else if (cmd == VFIO_IOMMU_GET_INFO) {
1549 struct vfio_iommu_type1_info info;
1551 minsz = offsetofend(struct vfio_iommu_type1_info, iova_pgsizes);
1553 if (copy_from_user(&info, (void __user *)arg, minsz))
1556 if (info.argsz < minsz)
1559 info.flags = VFIO_IOMMU_INFO_PGSIZES;
1561 info.iova_pgsizes = vfio_pgsize_bitmap(iommu);
1563 return copy_to_user((void __user *)arg, &info, minsz) ?
1566 } else if (cmd == VFIO_IOMMU_MAP_DMA) {
1567 struct vfio_iommu_type1_dma_map map;
1568 uint32_t mask = VFIO_DMA_MAP_FLAG_READ |
1569 VFIO_DMA_MAP_FLAG_WRITE;
1571 minsz = offsetofend(struct vfio_iommu_type1_dma_map, size);
1573 if (copy_from_user(&map, (void __user *)arg, minsz))
1576 if (map.argsz < minsz || map.flags & ~mask)
1579 return vfio_dma_do_map(iommu, &map);
1581 } else if (cmd == VFIO_IOMMU_UNMAP_DMA) {
1582 struct vfio_iommu_type1_dma_unmap unmap;
1585 minsz = offsetofend(struct vfio_iommu_type1_dma_unmap, size);
1587 if (copy_from_user(&unmap, (void __user *)arg, minsz))
1590 if (unmap.argsz < minsz || unmap.flags)
1593 ret = vfio_dma_do_unmap(iommu, &unmap);
1597 return copy_to_user((void __user *)arg, &unmap, minsz) ?
1604 static int vfio_iommu_type1_register_notifier(void *iommu_data,
1605 unsigned long *events,
1606 struct notifier_block *nb)
1608 struct vfio_iommu *iommu = iommu_data;
1610 /* clear known events */
1611 *events &= ~VFIO_IOMMU_NOTIFY_DMA_UNMAP;
1613 /* refuse to register if still events remaining */
1617 return blocking_notifier_chain_register(&iommu->notifier, nb);
1620 static int vfio_iommu_type1_unregister_notifier(void *iommu_data,
1621 struct notifier_block *nb)
1623 struct vfio_iommu *iommu = iommu_data;
1625 return blocking_notifier_chain_unregister(&iommu->notifier, nb);
1628 static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1 = {
1629 .name = "vfio-iommu-type1",
1630 .owner = THIS_MODULE,
1631 .open = vfio_iommu_type1_open,
1632 .release = vfio_iommu_type1_release,
1633 .ioctl = vfio_iommu_type1_ioctl,
1634 .attach_group = vfio_iommu_type1_attach_group,
1635 .detach_group = vfio_iommu_type1_detach_group,
1636 .pin_pages = vfio_iommu_type1_pin_pages,
1637 .unpin_pages = vfio_iommu_type1_unpin_pages,
1638 .register_notifier = vfio_iommu_type1_register_notifier,
1639 .unregister_notifier = vfio_iommu_type1_unregister_notifier,
1642 static int __init vfio_iommu_type1_init(void)
1644 return vfio_register_iommu_driver(&vfio_iommu_driver_ops_type1);
1647 static void __exit vfio_iommu_type1_cleanup(void)
1649 vfio_unregister_iommu_driver(&vfio_iommu_driver_ops_type1);
1652 module_init(vfio_iommu_type1_init);
1653 module_exit(vfio_iommu_type1_cleanup);
1655 MODULE_VERSION(DRIVER_VERSION);
1656 MODULE_LICENSE("GPL v2");
1657 MODULE_AUTHOR(DRIVER_AUTHOR);
1658 MODULE_DESCRIPTION(DRIVER_DESC);