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.h>
35 #include <linux/slab.h>
36 #include <linux/uaccess.h>
37 #include <linux/vfio.h>
38 #include <linux/workqueue.h>
39 #include <linux/pid_namespace.h>
40 #include <linux/mdev.h>
41 #include <linux/notifier.h>
43 #define DRIVER_VERSION "0.2"
44 #define DRIVER_AUTHOR "Alex Williamson <alex.williamson@redhat.com>"
45 #define DRIVER_DESC "Type1 IOMMU driver for VFIO"
47 static bool allow_unsafe_interrupts
;
48 module_param_named(allow_unsafe_interrupts
,
49 allow_unsafe_interrupts
, bool, S_IRUGO
| S_IWUSR
);
50 MODULE_PARM_DESC(allow_unsafe_interrupts
,
51 "Enable VFIO IOMMU support for on platforms without interrupt remapping support.");
53 static bool disable_hugepages
;
54 module_param_named(disable_hugepages
,
55 disable_hugepages
, bool, S_IRUGO
| S_IWUSR
);
56 MODULE_PARM_DESC(disable_hugepages
,
57 "Disable VFIO IOMMU support for IOMMU hugepages.");
60 struct list_head domain_list
;
61 struct vfio_domain
*external_domain
; /* domain for external user */
63 struct rb_root dma_list
;
64 struct blocking_notifier_head notifier
;
70 struct iommu_domain
*domain
;
71 struct list_head next
;
72 struct list_head group_list
;
73 int prot
; /* IOMMU_CACHE */
74 bool fgsp
; /* Fine-grained super pages */
79 dma_addr_t iova
; /* Device address */
80 unsigned long vaddr
; /* Process virtual addr */
81 size_t size
; /* Map size (bytes) */
82 int prot
; /* IOMMU_READ/WRITE */
84 struct task_struct
*task
;
85 struct rb_root pfn_list
; /* Ex-user pinned pfn list */
89 struct iommu_group
*iommu_group
;
90 struct list_head next
;
94 * Guest RAM pinning working set or DMA target
98 dma_addr_t iova
; /* Device address */
99 unsigned long pfn
; /* Host pfn */
103 #define IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu) \
104 (!list_empty(&iommu->domain_list))
106 static int put_pfn(unsigned long pfn
, int prot
);
109 * This code handles mapping and unmapping of user data buffers
110 * into DMA'ble space using the IOMMU
113 static struct vfio_dma
*vfio_find_dma(struct vfio_iommu
*iommu
,
114 dma_addr_t start
, size_t size
)
116 struct rb_node
*node
= iommu
->dma_list
.rb_node
;
119 struct vfio_dma
*dma
= rb_entry(node
, struct vfio_dma
, node
);
121 if (start
+ size
<= dma
->iova
)
122 node
= node
->rb_left
;
123 else if (start
>= dma
->iova
+ dma
->size
)
124 node
= node
->rb_right
;
132 static void vfio_link_dma(struct vfio_iommu
*iommu
, struct vfio_dma
*new)
134 struct rb_node
**link
= &iommu
->dma_list
.rb_node
, *parent
= NULL
;
135 struct vfio_dma
*dma
;
139 dma
= rb_entry(parent
, struct vfio_dma
, node
);
141 if (new->iova
+ new->size
<= dma
->iova
)
142 link
= &(*link
)->rb_left
;
144 link
= &(*link
)->rb_right
;
147 rb_link_node(&new->node
, parent
, link
);
148 rb_insert_color(&new->node
, &iommu
->dma_list
);
151 static void vfio_unlink_dma(struct vfio_iommu
*iommu
, struct vfio_dma
*old
)
153 rb_erase(&old
->node
, &iommu
->dma_list
);
157 * Helper Functions for host iova-pfn list
159 static struct vfio_pfn
*vfio_find_vpfn(struct vfio_dma
*dma
, dma_addr_t iova
)
161 struct vfio_pfn
*vpfn
;
162 struct rb_node
*node
= dma
->pfn_list
.rb_node
;
165 vpfn
= rb_entry(node
, struct vfio_pfn
, node
);
167 if (iova
< vpfn
->iova
)
168 node
= node
->rb_left
;
169 else if (iova
> vpfn
->iova
)
170 node
= node
->rb_right
;
177 static void vfio_link_pfn(struct vfio_dma
*dma
,
178 struct vfio_pfn
*new)
180 struct rb_node
**link
, *parent
= NULL
;
181 struct vfio_pfn
*vpfn
;
183 link
= &dma
->pfn_list
.rb_node
;
186 vpfn
= rb_entry(parent
, struct vfio_pfn
, node
);
188 if (new->iova
< vpfn
->iova
)
189 link
= &(*link
)->rb_left
;
191 link
= &(*link
)->rb_right
;
194 rb_link_node(&new->node
, parent
, link
);
195 rb_insert_color(&new->node
, &dma
->pfn_list
);
198 static void vfio_unlink_pfn(struct vfio_dma
*dma
, struct vfio_pfn
*old
)
200 rb_erase(&old
->node
, &dma
->pfn_list
);
203 static int vfio_add_to_pfn_list(struct vfio_dma
*dma
, dma_addr_t iova
,
206 struct vfio_pfn
*vpfn
;
208 vpfn
= kzalloc(sizeof(*vpfn
), GFP_KERNEL
);
214 atomic_set(&vpfn
->ref_count
, 1);
215 vfio_link_pfn(dma
, vpfn
);
219 static void vfio_remove_from_pfn_list(struct vfio_dma
*dma
,
220 struct vfio_pfn
*vpfn
)
222 vfio_unlink_pfn(dma
, vpfn
);
226 static struct vfio_pfn
*vfio_iova_get_vfio_pfn(struct vfio_dma
*dma
,
229 struct vfio_pfn
*vpfn
= vfio_find_vpfn(dma
, iova
);
232 atomic_inc(&vpfn
->ref_count
);
236 static int vfio_iova_put_vfio_pfn(struct vfio_dma
*dma
, struct vfio_pfn
*vpfn
)
240 if (atomic_dec_and_test(&vpfn
->ref_count
)) {
241 ret
= put_pfn(vpfn
->pfn
, dma
->prot
);
242 vfio_remove_from_pfn_list(dma
, vpfn
);
248 struct mm_struct
*mm
;
250 struct work_struct work
;
253 /* delayed decrement/increment for locked_vm */
254 static void vfio_lock_acct_bg(struct work_struct
*work
)
256 struct vwork
*vwork
= container_of(work
, struct vwork
, work
);
257 struct mm_struct
*mm
;
260 down_write(&mm
->mmap_sem
);
261 mm
->locked_vm
+= vwork
->npage
;
262 up_write(&mm
->mmap_sem
);
267 static void vfio_lock_acct(struct task_struct
*task
, long npage
)
270 struct mm_struct
*mm
;
275 mm
= get_task_mm(task
);
277 return; /* process exited or nothing to do */
279 if (down_write_trylock(&mm
->mmap_sem
)) {
280 mm
->locked_vm
+= npage
;
281 up_write(&mm
->mmap_sem
);
287 * Couldn't get mmap_sem lock, so must setup to update
288 * mm->locked_vm later. If locked_vm were atomic, we
289 * wouldn't need this silliness
291 vwork
= kmalloc(sizeof(struct vwork
), GFP_KERNEL
);
296 INIT_WORK(&vwork
->work
, vfio_lock_acct_bg
);
298 vwork
->npage
= npage
;
299 schedule_work(&vwork
->work
);
303 * Some mappings aren't backed by a struct page, for example an mmap'd
304 * MMIO range for our own or another device. These use a different
305 * pfn conversion and shouldn't be tracked as locked pages.
307 static bool is_invalid_reserved_pfn(unsigned long pfn
)
309 if (pfn_valid(pfn
)) {
311 struct page
*tail
= pfn_to_page(pfn
);
312 struct page
*head
= compound_head(tail
);
313 reserved
= !!(PageReserved(head
));
316 * "head" is not a dangling pointer
317 * (compound_head takes care of that)
318 * but the hugepage may have been split
319 * from under us (and we may not hold a
320 * reference count on the head page so it can
321 * be reused before we run PageReferenced), so
322 * we've to check PageTail before returning
329 return PageReserved(tail
);
335 static int put_pfn(unsigned long pfn
, int prot
)
337 if (!is_invalid_reserved_pfn(pfn
)) {
338 struct page
*page
= pfn_to_page(pfn
);
339 if (prot
& IOMMU_WRITE
)
347 static int vaddr_get_pfn(struct mm_struct
*mm
, unsigned long vaddr
,
348 int prot
, unsigned long *pfn
)
350 struct page
*page
[1];
351 struct vm_area_struct
*vma
;
354 if (mm
== current
->mm
) {
355 ret
= get_user_pages_fast(vaddr
, 1, !!(prot
& IOMMU_WRITE
),
358 unsigned int flags
= 0;
360 if (prot
& IOMMU_WRITE
)
363 down_read(&mm
->mmap_sem
);
364 ret
= get_user_pages_remote(NULL
, mm
, vaddr
, 1, flags
, page
,
366 up_read(&mm
->mmap_sem
);
370 *pfn
= page_to_pfn(page
[0]);
374 down_read(&mm
->mmap_sem
);
376 vma
= find_vma_intersection(mm
, vaddr
, vaddr
+ 1);
378 if (vma
&& vma
->vm_flags
& VM_PFNMAP
) {
379 *pfn
= ((vaddr
- vma
->vm_start
) >> PAGE_SHIFT
) + vma
->vm_pgoff
;
380 if (is_invalid_reserved_pfn(*pfn
))
384 up_read(&mm
->mmap_sem
);
389 * Attempt to pin pages. We really don't want to track all the pfns and
390 * the iommu can only map chunks of consecutive pfns anyway, so get the
391 * first page and all consecutive pages with the same locking.
393 static long vfio_pin_pages_remote(struct vfio_dma
*dma
, unsigned long vaddr
,
394 long npage
, unsigned long *pfn_base
)
397 bool lock_cap
= ns_capable(task_active_pid_ns(dma
->task
)->user_ns
,
399 struct mm_struct
*mm
;
400 long ret
, i
= 0, lock_acct
= 0;
402 dma_addr_t iova
= vaddr
- dma
->vaddr
+ dma
->iova
;
404 mm
= get_task_mm(dma
->task
);
408 ret
= vaddr_get_pfn(mm
, vaddr
, dma
->prot
, pfn_base
);
410 goto pin_pg_remote_exit
;
412 rsvd
= is_invalid_reserved_pfn(*pfn_base
);
413 limit
= task_rlimit(dma
->task
, RLIMIT_MEMLOCK
) >> PAGE_SHIFT
;
416 * Reserved pages aren't counted against the user, externally pinned
417 * pages are already counted against the user.
419 if (!rsvd
&& !vfio_find_vpfn(dma
, iova
)) {
420 if (!lock_cap
&& mm
->locked_vm
+ 1 > limit
) {
421 put_pfn(*pfn_base
, dma
->prot
);
422 pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n", __func__
,
423 limit
<< PAGE_SHIFT
);
425 goto pin_pg_remote_exit
;
431 if (likely(!disable_hugepages
)) {
432 /* Lock all the consecutive pages from pfn_base */
433 for (vaddr
+= PAGE_SIZE
, iova
+= PAGE_SIZE
; i
< npage
;
434 i
++, vaddr
+= PAGE_SIZE
, iova
+= PAGE_SIZE
) {
435 unsigned long pfn
= 0;
437 ret
= vaddr_get_pfn(mm
, vaddr
, dma
->prot
, &pfn
);
441 if (pfn
!= *pfn_base
+ i
||
442 rsvd
!= is_invalid_reserved_pfn(pfn
)) {
443 put_pfn(pfn
, dma
->prot
);
447 if (!rsvd
&& !vfio_find_vpfn(dma
, iova
)) {
449 mm
->locked_vm
+ lock_acct
+ 1 > limit
) {
450 put_pfn(pfn
, dma
->prot
);
451 pr_warn("%s: RLIMIT_MEMLOCK (%ld) "
452 "exceeded\n", __func__
,
453 limit
<< PAGE_SHIFT
);
461 vfio_lock_acct(dma
->task
, lock_acct
);
469 static long vfio_unpin_pages_remote(struct vfio_dma
*dma
, dma_addr_t iova
,
470 unsigned long pfn
, long npage
,
473 long unlocked
= 0, locked
= 0;
476 for (i
= 0; i
< npage
; i
++) {
477 if (put_pfn(pfn
++, dma
->prot
)) {
479 if (vfio_find_vpfn(dma
, iova
+ (i
<< PAGE_SHIFT
)))
485 vfio_lock_acct(dma
->task
, locked
- unlocked
);
490 static int vfio_pin_page_external(struct vfio_dma
*dma
, unsigned long vaddr
,
491 unsigned long *pfn_base
, bool do_accounting
)
494 bool lock_cap
= ns_capable(task_active_pid_ns(dma
->task
)->user_ns
,
496 struct mm_struct
*mm
;
500 mm
= get_task_mm(dma
->task
);
504 ret
= vaddr_get_pfn(mm
, vaddr
, dma
->prot
, pfn_base
);
508 rsvd
= is_invalid_reserved_pfn(*pfn_base
);
509 limit
= task_rlimit(dma
->task
, RLIMIT_MEMLOCK
) >> PAGE_SHIFT
;
511 if (!rsvd
&& !lock_cap
&& mm
->locked_vm
+ 1 > limit
) {
512 put_pfn(*pfn_base
, dma
->prot
);
513 pr_warn("%s: Task %s (%d) RLIMIT_MEMLOCK (%ld) exceeded\n",
514 __func__
, dma
->task
->comm
, task_pid_nr(dma
->task
),
515 limit
<< PAGE_SHIFT
);
520 if (!rsvd
&& do_accounting
)
521 vfio_lock_acct(dma
->task
, 1);
529 static int vfio_unpin_page_external(struct vfio_dma
*dma
, dma_addr_t iova
,
533 struct vfio_pfn
*vpfn
= vfio_find_vpfn(dma
, iova
);
538 unlocked
= vfio_iova_put_vfio_pfn(dma
, vpfn
);
541 vfio_lock_acct(dma
->task
, -unlocked
);
546 static int vfio_iommu_type1_pin_pages(void *iommu_data
,
547 unsigned long *user_pfn
,
549 unsigned long *phys_pfn
)
551 struct vfio_iommu
*iommu
= iommu_data
;
553 unsigned long remote_vaddr
;
554 struct vfio_dma
*dma
;
557 if (!iommu
|| !user_pfn
|| !phys_pfn
)
560 /* Supported for v2 version only */
564 mutex_lock(&iommu
->lock
);
566 /* Fail if notifier list is empty */
567 if ((!iommu
->external_domain
) || (!iommu
->notifier
.head
)) {
573 * If iommu capable domain exist in the container then all pages are
574 * already pinned and accounted. Accouting should be done if there is no
575 * iommu capable domain in the container.
577 do_accounting
= !IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu
);
579 for (i
= 0; i
< npage
; i
++) {
581 struct vfio_pfn
*vpfn
;
583 iova
= user_pfn
[i
] << PAGE_SHIFT
;
584 dma
= vfio_find_dma(iommu
, iova
, 0);
590 if ((dma
->prot
& prot
) != prot
) {
595 vpfn
= vfio_iova_get_vfio_pfn(dma
, iova
);
597 phys_pfn
[i
] = vpfn
->pfn
;
601 remote_vaddr
= dma
->vaddr
+ iova
- dma
->iova
;
602 ret
= vfio_pin_page_external(dma
, remote_vaddr
, &phys_pfn
[i
],
609 ret
= vfio_add_to_pfn_list(dma
, iova
, phys_pfn
[i
]);
611 vfio_unpin_page_external(dma
, iova
, do_accounting
);
621 for (j
= 0; j
< i
; j
++) {
624 iova
= user_pfn
[j
] << PAGE_SHIFT
;
625 dma
= vfio_find_dma(iommu
, iova
, 0);
626 vfio_unpin_page_external(dma
, iova
, do_accounting
);
630 mutex_unlock(&iommu
->lock
);
634 static int vfio_iommu_type1_unpin_pages(void *iommu_data
,
635 unsigned long *user_pfn
,
638 struct vfio_iommu
*iommu
= iommu_data
;
642 if (!iommu
|| !user_pfn
)
645 /* Supported for v2 version only */
649 mutex_lock(&iommu
->lock
);
651 if (!iommu
->external_domain
) {
652 mutex_unlock(&iommu
->lock
);
656 do_accounting
= !IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu
);
657 for (i
= 0; i
< npage
; i
++) {
658 struct vfio_dma
*dma
;
661 iova
= user_pfn
[i
] << PAGE_SHIFT
;
662 dma
= vfio_find_dma(iommu
, iova
, 0);
665 vfio_unpin_page_external(dma
, iova
, do_accounting
);
669 mutex_unlock(&iommu
->lock
);
670 return i
> npage
? npage
: (i
> 0 ? i
: -EINVAL
);
673 static long vfio_unmap_unpin(struct vfio_iommu
*iommu
, struct vfio_dma
*dma
,
676 dma_addr_t iova
= dma
->iova
, end
= dma
->iova
+ dma
->size
;
677 struct vfio_domain
*domain
, *d
;
683 if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu
))
687 * We use the IOMMU to track the physical addresses, otherwise we'd
688 * need a much more complicated tracking system. Unfortunately that
689 * means we need to use one of the iommu domains to figure out the
690 * pfns to unpin. The rest need to be unmapped in advance so we have
691 * no iommu translations remaining when the pages are unpinned.
693 domain
= d
= list_first_entry(&iommu
->domain_list
,
694 struct vfio_domain
, next
);
696 list_for_each_entry_continue(d
, &iommu
->domain_list
, next
) {
697 iommu_unmap(d
->domain
, dma
->iova
, dma
->size
);
702 size_t unmapped
, len
;
703 phys_addr_t phys
, next
;
705 phys
= iommu_iova_to_phys(domain
->domain
, iova
);
706 if (WARN_ON(!phys
)) {
712 * To optimize for fewer iommu_unmap() calls, each of which
713 * may require hardware cache flushing, try to find the
714 * largest contiguous physical memory chunk to unmap.
716 for (len
= PAGE_SIZE
;
717 !domain
->fgsp
&& iova
+ len
< end
; len
+= PAGE_SIZE
) {
718 next
= iommu_iova_to_phys(domain
->domain
, iova
+ len
);
719 if (next
!= phys
+ len
)
723 unmapped
= iommu_unmap(domain
->domain
, iova
, len
);
724 if (WARN_ON(!unmapped
))
727 unlocked
+= vfio_unpin_pages_remote(dma
, iova
,
729 unmapped
>> PAGE_SHIFT
,
736 dma
->iommu_mapped
= false;
738 vfio_lock_acct(dma
->task
, -unlocked
);
744 static void vfio_remove_dma(struct vfio_iommu
*iommu
, struct vfio_dma
*dma
)
746 vfio_unmap_unpin(iommu
, dma
, true);
747 vfio_unlink_dma(iommu
, dma
);
748 put_task_struct(dma
->task
);
752 static unsigned long vfio_pgsize_bitmap(struct vfio_iommu
*iommu
)
754 struct vfio_domain
*domain
;
755 unsigned long bitmap
= ULONG_MAX
;
757 mutex_lock(&iommu
->lock
);
758 list_for_each_entry(domain
, &iommu
->domain_list
, next
)
759 bitmap
&= domain
->domain
->pgsize_bitmap
;
760 mutex_unlock(&iommu
->lock
);
763 * In case the IOMMU supports page sizes smaller than PAGE_SIZE
764 * we pretend PAGE_SIZE is supported and hide sub-PAGE_SIZE sizes.
765 * That way the user will be able to map/unmap buffers whose size/
766 * start address is aligned with PAGE_SIZE. Pinning code uses that
767 * granularity while iommu driver can use the sub-PAGE_SIZE size
770 if (bitmap
& ~PAGE_MASK
) {
778 static int vfio_dma_do_unmap(struct vfio_iommu
*iommu
,
779 struct vfio_iommu_type1_dma_unmap
*unmap
)
782 struct vfio_dma
*dma
, *dma_last
= NULL
;
784 int ret
= 0, retries
= 0;
786 mask
= ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu
))) - 1;
788 if (unmap
->iova
& mask
)
790 if (!unmap
->size
|| unmap
->size
& mask
)
793 WARN_ON(mask
& PAGE_MASK
);
795 mutex_lock(&iommu
->lock
);
798 * vfio-iommu-type1 (v1) - User mappings were coalesced together to
799 * avoid tracking individual mappings. This means that the granularity
800 * of the original mapping was lost and the user was allowed to attempt
801 * to unmap any range. Depending on the contiguousness of physical
802 * memory and page sizes supported by the IOMMU, arbitrary unmaps may
803 * or may not have worked. We only guaranteed unmap granularity
804 * matching the original mapping; even though it was untracked here,
805 * the original mappings are reflected in IOMMU mappings. This
806 * resulted in a couple unusual behaviors. First, if a range is not
807 * able to be unmapped, ex. a set of 4k pages that was mapped as a
808 * 2M hugepage into the IOMMU, the unmap ioctl returns success but with
809 * a zero sized unmap. Also, if an unmap request overlaps the first
810 * address of a hugepage, the IOMMU will unmap the entire hugepage.
811 * This also returns success and the returned unmap size reflects the
812 * actual size unmapped.
814 * We attempt to maintain compatibility with this "v1" interface, but
815 * we take control out of the hands of the IOMMU. Therefore, an unmap
816 * request offset from the beginning of the original mapping will
817 * return success with zero sized unmap. And an unmap request covering
818 * the first iova of mapping will unmap the entire range.
820 * The v2 version of this interface intends to be more deterministic.
821 * Unmap requests must fully cover previous mappings. Multiple
822 * mappings may still be unmaped by specifying large ranges, but there
823 * must not be any previous mappings bisected by the range. An error
824 * will be returned if these conditions are not met. The v2 interface
825 * will only return success and a size of zero if there were no
826 * mappings within the range.
829 dma
= vfio_find_dma(iommu
, unmap
->iova
, 0);
830 if (dma
&& dma
->iova
!= unmap
->iova
) {
834 dma
= vfio_find_dma(iommu
, unmap
->iova
+ unmap
->size
- 1, 0);
835 if (dma
&& dma
->iova
+ dma
->size
!= unmap
->iova
+ unmap
->size
) {
841 while ((dma
= vfio_find_dma(iommu
, unmap
->iova
, unmap
->size
))) {
842 if (!iommu
->v2
&& unmap
->iova
> dma
->iova
)
845 * Task with same address space who mapped this iova range is
846 * allowed to unmap the iova range.
848 if (dma
->task
->mm
!= current
->mm
)
851 if (!RB_EMPTY_ROOT(&dma
->pfn_list
)) {
852 struct vfio_iommu_type1_dma_unmap nb_unmap
;
854 if (dma_last
== dma
) {
855 BUG_ON(++retries
> 10);
861 nb_unmap
.iova
= dma
->iova
;
862 nb_unmap
.size
= dma
->size
;
865 * Notify anyone (mdev vendor drivers) to invalidate and
866 * unmap iovas within the range we're about to unmap.
867 * Vendor drivers MUST unpin pages in response to an
870 mutex_unlock(&iommu
->lock
);
871 blocking_notifier_call_chain(&iommu
->notifier
,
872 VFIO_IOMMU_NOTIFY_DMA_UNMAP
,
876 unmapped
+= dma
->size
;
877 vfio_remove_dma(iommu
, dma
);
881 mutex_unlock(&iommu
->lock
);
883 /* Report how much was unmapped */
884 unmap
->size
= unmapped
;
890 * Turns out AMD IOMMU has a page table bug where it won't map large pages
891 * to a region that previously mapped smaller pages. This should be fixed
892 * soon, so this is just a temporary workaround to break mappings down into
893 * PAGE_SIZE. Better to map smaller pages than nothing.
895 static int map_try_harder(struct vfio_domain
*domain
, dma_addr_t iova
,
896 unsigned long pfn
, long npage
, int prot
)
901 for (i
= 0; i
< npage
; i
++, pfn
++, iova
+= PAGE_SIZE
) {
902 ret
= iommu_map(domain
->domain
, iova
,
903 (phys_addr_t
)pfn
<< PAGE_SHIFT
,
904 PAGE_SIZE
, prot
| domain
->prot
);
909 for (; i
< npage
&& i
> 0; i
--, iova
-= PAGE_SIZE
)
910 iommu_unmap(domain
->domain
, iova
, PAGE_SIZE
);
915 static int vfio_iommu_map(struct vfio_iommu
*iommu
, dma_addr_t iova
,
916 unsigned long pfn
, long npage
, int prot
)
918 struct vfio_domain
*d
;
921 list_for_each_entry(d
, &iommu
->domain_list
, next
) {
922 ret
= iommu_map(d
->domain
, iova
, (phys_addr_t
)pfn
<< PAGE_SHIFT
,
923 npage
<< PAGE_SHIFT
, prot
| d
->prot
);
926 map_try_harder(d
, iova
, pfn
, npage
, prot
))
936 list_for_each_entry_continue_reverse(d
, &iommu
->domain_list
, next
)
937 iommu_unmap(d
->domain
, iova
, npage
<< PAGE_SHIFT
);
942 static int vfio_pin_map_dma(struct vfio_iommu
*iommu
, struct vfio_dma
*dma
,
945 dma_addr_t iova
= dma
->iova
;
946 unsigned long vaddr
= dma
->vaddr
;
947 size_t size
= map_size
;
953 /* Pin a contiguous chunk of memory */
954 npage
= vfio_pin_pages_remote(dma
, vaddr
+ dma
->size
,
955 size
>> PAGE_SHIFT
, &pfn
);
963 ret
= vfio_iommu_map(iommu
, iova
+ dma
->size
, pfn
, npage
,
966 vfio_unpin_pages_remote(dma
, iova
+ dma
->size
, pfn
,
971 size
-= npage
<< PAGE_SHIFT
;
972 dma
->size
+= npage
<< PAGE_SHIFT
;
975 dma
->iommu_mapped
= true;
978 vfio_remove_dma(iommu
, dma
);
983 static int vfio_dma_do_map(struct vfio_iommu
*iommu
,
984 struct vfio_iommu_type1_dma_map
*map
)
986 dma_addr_t iova
= map
->iova
;
987 unsigned long vaddr
= map
->vaddr
;
988 size_t size
= map
->size
;
989 int ret
= 0, prot
= 0;
991 struct vfio_dma
*dma
;
993 /* Verify that none of our __u64 fields overflow */
994 if (map
->size
!= size
|| map
->vaddr
!= vaddr
|| map
->iova
!= iova
)
997 mask
= ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu
))) - 1;
999 WARN_ON(mask
& PAGE_MASK
);
1001 /* READ/WRITE from device perspective */
1002 if (map
->flags
& VFIO_DMA_MAP_FLAG_WRITE
)
1003 prot
|= IOMMU_WRITE
;
1004 if (map
->flags
& VFIO_DMA_MAP_FLAG_READ
)
1007 if (!prot
|| !size
|| (size
| iova
| vaddr
) & mask
)
1010 /* Don't allow IOVA or virtual address wrap */
1011 if (iova
+ size
- 1 < iova
|| vaddr
+ size
- 1 < vaddr
)
1014 mutex_lock(&iommu
->lock
);
1016 if (vfio_find_dma(iommu
, iova
, size
)) {
1021 dma
= kzalloc(sizeof(*dma
), GFP_KERNEL
);
1030 get_task_struct(current
);
1031 dma
->task
= current
;
1032 dma
->pfn_list
= RB_ROOT
;
1034 /* Insert zero-sized and grow as we map chunks of it */
1035 vfio_link_dma(iommu
, dma
);
1037 /* Don't pin and map if container doesn't contain IOMMU capable domain*/
1038 if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu
))
1041 ret
= vfio_pin_map_dma(iommu
, dma
, size
);
1044 mutex_unlock(&iommu
->lock
);
1048 static int vfio_bus_type(struct device
*dev
, void *data
)
1050 struct bus_type
**bus
= data
;
1052 if (*bus
&& *bus
!= dev
->bus
)
1060 static int vfio_iommu_replay(struct vfio_iommu
*iommu
,
1061 struct vfio_domain
*domain
)
1063 struct vfio_domain
*d
;
1067 /* Arbitrarily pick the first domain in the list for lookups */
1068 d
= list_first_entry(&iommu
->domain_list
, struct vfio_domain
, next
);
1069 n
= rb_first(&iommu
->dma_list
);
1071 for (; n
; n
= rb_next(n
)) {
1072 struct vfio_dma
*dma
;
1075 dma
= rb_entry(n
, struct vfio_dma
, node
);
1078 while (iova
< dma
->iova
+ dma
->size
) {
1082 if (dma
->iommu_mapped
) {
1086 phys
= iommu_iova_to_phys(d
->domain
, iova
);
1088 if (WARN_ON(!phys
)) {
1096 while (i
< dma
->iova
+ dma
->size
&&
1097 p
== iommu_iova_to_phys(d
->domain
, i
)) {
1104 unsigned long vaddr
= dma
->vaddr
+
1106 size_t n
= dma
->iova
+ dma
->size
- iova
;
1109 npage
= vfio_pin_pages_remote(dma
, vaddr
,
1118 phys
= pfn
<< PAGE_SHIFT
;
1119 size
= npage
<< PAGE_SHIFT
;
1122 ret
= iommu_map(domain
->domain
, iova
, phys
,
1123 size
, dma
->prot
| domain
->prot
);
1129 dma
->iommu_mapped
= true;
1135 * We change our unmap behavior slightly depending on whether the IOMMU
1136 * supports fine-grained superpages. IOMMUs like AMD-Vi will use a superpage
1137 * for practically any contiguous power-of-two mapping we give it. This means
1138 * we don't need to look for contiguous chunks ourselves to make unmapping
1139 * more efficient. On IOMMUs with coarse-grained super pages, like Intel VT-d
1140 * with discrete 2M/1G/512G/1T superpages, identifying contiguous chunks
1141 * significantly boosts non-hugetlbfs mappings and doesn't seem to hurt when
1142 * hugetlbfs is in use.
1144 static void vfio_test_domain_fgsp(struct vfio_domain
*domain
)
1147 int ret
, order
= get_order(PAGE_SIZE
* 2);
1149 pages
= alloc_pages(GFP_KERNEL
| __GFP_ZERO
, order
);
1153 ret
= iommu_map(domain
->domain
, 0, page_to_phys(pages
), PAGE_SIZE
* 2,
1154 IOMMU_READ
| IOMMU_WRITE
| domain
->prot
);
1156 size_t unmapped
= iommu_unmap(domain
->domain
, 0, PAGE_SIZE
);
1158 if (unmapped
== PAGE_SIZE
)
1159 iommu_unmap(domain
->domain
, PAGE_SIZE
, PAGE_SIZE
);
1161 domain
->fgsp
= true;
1164 __free_pages(pages
, order
);
1167 static struct vfio_group
*find_iommu_group(struct vfio_domain
*domain
,
1168 struct iommu_group
*iommu_group
)
1170 struct vfio_group
*g
;
1172 list_for_each_entry(g
, &domain
->group_list
, next
) {
1173 if (g
->iommu_group
== iommu_group
)
1180 static int vfio_iommu_type1_attach_group(void *iommu_data
,
1181 struct iommu_group
*iommu_group
)
1183 struct vfio_iommu
*iommu
= iommu_data
;
1184 struct vfio_group
*group
;
1185 struct vfio_domain
*domain
, *d
;
1186 struct bus_type
*bus
= NULL
, *mdev_bus
;
1189 mutex_lock(&iommu
->lock
);
1191 list_for_each_entry(d
, &iommu
->domain_list
, next
) {
1192 if (find_iommu_group(d
, iommu_group
)) {
1193 mutex_unlock(&iommu
->lock
);
1198 if (iommu
->external_domain
) {
1199 if (find_iommu_group(iommu
->external_domain
, iommu_group
)) {
1200 mutex_unlock(&iommu
->lock
);
1205 group
= kzalloc(sizeof(*group
), GFP_KERNEL
);
1206 domain
= kzalloc(sizeof(*domain
), GFP_KERNEL
);
1207 if (!group
|| !domain
) {
1212 group
->iommu_group
= iommu_group
;
1214 /* Determine bus_type in order to allocate a domain */
1215 ret
= iommu_group_for_each_dev(iommu_group
, &bus
, vfio_bus_type
);
1219 mdev_bus
= symbol_get(mdev_bus_type
);
1222 if ((bus
== mdev_bus
) && !iommu_present(bus
)) {
1223 symbol_put(mdev_bus_type
);
1224 if (!iommu
->external_domain
) {
1225 INIT_LIST_HEAD(&domain
->group_list
);
1226 iommu
->external_domain
= domain
;
1230 list_add(&group
->next
,
1231 &iommu
->external_domain
->group_list
);
1232 mutex_unlock(&iommu
->lock
);
1235 symbol_put(mdev_bus_type
);
1238 domain
->domain
= iommu_domain_alloc(bus
);
1239 if (!domain
->domain
) {
1244 if (iommu
->nesting
) {
1247 ret
= iommu_domain_set_attr(domain
->domain
, DOMAIN_ATTR_NESTING
,
1253 ret
= iommu_attach_group(domain
->domain
, iommu_group
);
1257 INIT_LIST_HEAD(&domain
->group_list
);
1258 list_add(&group
->next
, &domain
->group_list
);
1260 if (!allow_unsafe_interrupts
&&
1261 !iommu_capable(bus
, IOMMU_CAP_INTR_REMAP
)) {
1262 pr_warn("%s: No interrupt remapping support. Use the module param \"allow_unsafe_interrupts\" to enable VFIO IOMMU support on this platform\n",
1268 if (iommu_capable(bus
, IOMMU_CAP_CACHE_COHERENCY
))
1269 domain
->prot
|= IOMMU_CACHE
;
1272 * Try to match an existing compatible domain. We don't want to
1273 * preclude an IOMMU driver supporting multiple bus_types and being
1274 * able to include different bus_types in the same IOMMU domain, so
1275 * we test whether the domains use the same iommu_ops rather than
1276 * testing if they're on the same bus_type.
1278 list_for_each_entry(d
, &iommu
->domain_list
, next
) {
1279 if (d
->domain
->ops
== domain
->domain
->ops
&&
1280 d
->prot
== domain
->prot
) {
1281 iommu_detach_group(domain
->domain
, iommu_group
);
1282 if (!iommu_attach_group(d
->domain
, iommu_group
)) {
1283 list_add(&group
->next
, &d
->group_list
);
1284 iommu_domain_free(domain
->domain
);
1286 mutex_unlock(&iommu
->lock
);
1290 ret
= iommu_attach_group(domain
->domain
, iommu_group
);
1296 vfio_test_domain_fgsp(domain
);
1298 /* replay mappings on new domains */
1299 ret
= vfio_iommu_replay(iommu
, domain
);
1303 list_add(&domain
->next
, &iommu
->domain_list
);
1305 mutex_unlock(&iommu
->lock
);
1310 iommu_detach_group(domain
->domain
, iommu_group
);
1312 iommu_domain_free(domain
->domain
);
1316 mutex_unlock(&iommu
->lock
);
1320 static void vfio_iommu_unmap_unpin_all(struct vfio_iommu
*iommu
)
1322 struct rb_node
*node
;
1324 while ((node
= rb_first(&iommu
->dma_list
)))
1325 vfio_remove_dma(iommu
, rb_entry(node
, struct vfio_dma
, node
));
1328 static void vfio_iommu_unmap_unpin_reaccount(struct vfio_iommu
*iommu
)
1330 struct rb_node
*n
, *p
;
1332 n
= rb_first(&iommu
->dma_list
);
1333 for (; n
; n
= rb_next(n
)) {
1334 struct vfio_dma
*dma
;
1335 long locked
= 0, unlocked
= 0;
1337 dma
= rb_entry(n
, struct vfio_dma
, node
);
1338 unlocked
+= vfio_unmap_unpin(iommu
, dma
, false);
1339 p
= rb_first(&dma
->pfn_list
);
1340 for (; p
; p
= rb_next(p
)) {
1341 struct vfio_pfn
*vpfn
= rb_entry(p
, struct vfio_pfn
,
1344 if (!is_invalid_reserved_pfn(vpfn
->pfn
))
1347 vfio_lock_acct(dma
->task
, locked
- unlocked
);
1351 static void vfio_sanity_check_pfn_list(struct vfio_iommu
*iommu
)
1355 n
= rb_first(&iommu
->dma_list
);
1356 for (; n
; n
= rb_next(n
)) {
1357 struct vfio_dma
*dma
;
1359 dma
= rb_entry(n
, struct vfio_dma
, node
);
1361 if (WARN_ON(!RB_EMPTY_ROOT(&dma
->pfn_list
)))
1364 /* mdev vendor driver must unregister notifier */
1365 WARN_ON(iommu
->notifier
.head
);
1368 static void vfio_iommu_type1_detach_group(void *iommu_data
,
1369 struct iommu_group
*iommu_group
)
1371 struct vfio_iommu
*iommu
= iommu_data
;
1372 struct vfio_domain
*domain
;
1373 struct vfio_group
*group
;
1375 mutex_lock(&iommu
->lock
);
1377 if (iommu
->external_domain
) {
1378 group
= find_iommu_group(iommu
->external_domain
, iommu_group
);
1380 list_del(&group
->next
);
1383 if (list_empty(&iommu
->external_domain
->group_list
)) {
1384 vfio_sanity_check_pfn_list(iommu
);
1386 if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu
))
1387 vfio_iommu_unmap_unpin_all(iommu
);
1389 kfree(iommu
->external_domain
);
1390 iommu
->external_domain
= NULL
;
1392 goto detach_group_done
;
1396 list_for_each_entry(domain
, &iommu
->domain_list
, next
) {
1397 group
= find_iommu_group(domain
, iommu_group
);
1401 iommu_detach_group(domain
->domain
, iommu_group
);
1402 list_del(&group
->next
);
1405 * Group ownership provides privilege, if the group list is
1406 * empty, the domain goes away. If it's the last domain with
1407 * iommu and external domain doesn't exist, then all the
1408 * mappings go away too. If it's the last domain with iommu and
1409 * external domain exist, update accounting
1411 if (list_empty(&domain
->group_list
)) {
1412 if (list_is_singular(&iommu
->domain_list
)) {
1413 if (!iommu
->external_domain
)
1414 vfio_iommu_unmap_unpin_all(iommu
);
1416 vfio_iommu_unmap_unpin_reaccount(iommu
);
1418 iommu_domain_free(domain
->domain
);
1419 list_del(&domain
->next
);
1426 mutex_unlock(&iommu
->lock
);
1429 static void *vfio_iommu_type1_open(unsigned long arg
)
1431 struct vfio_iommu
*iommu
;
1433 iommu
= kzalloc(sizeof(*iommu
), GFP_KERNEL
);
1435 return ERR_PTR(-ENOMEM
);
1438 case VFIO_TYPE1_IOMMU
:
1440 case VFIO_TYPE1_NESTING_IOMMU
:
1441 iommu
->nesting
= true;
1442 case VFIO_TYPE1v2_IOMMU
:
1447 return ERR_PTR(-EINVAL
);
1450 INIT_LIST_HEAD(&iommu
->domain_list
);
1451 iommu
->dma_list
= RB_ROOT
;
1452 mutex_init(&iommu
->lock
);
1453 BLOCKING_INIT_NOTIFIER_HEAD(&iommu
->notifier
);
1458 static void vfio_release_domain(struct vfio_domain
*domain
, bool external
)
1460 struct vfio_group
*group
, *group_tmp
;
1462 list_for_each_entry_safe(group
, group_tmp
,
1463 &domain
->group_list
, next
) {
1465 iommu_detach_group(domain
->domain
, group
->iommu_group
);
1466 list_del(&group
->next
);
1471 iommu_domain_free(domain
->domain
);
1474 static void vfio_iommu_type1_release(void *iommu_data
)
1476 struct vfio_iommu
*iommu
= iommu_data
;
1477 struct vfio_domain
*domain
, *domain_tmp
;
1479 if (iommu
->external_domain
) {
1480 vfio_release_domain(iommu
->external_domain
, true);
1481 vfio_sanity_check_pfn_list(iommu
);
1482 kfree(iommu
->external_domain
);
1485 vfio_iommu_unmap_unpin_all(iommu
);
1487 list_for_each_entry_safe(domain
, domain_tmp
,
1488 &iommu
->domain_list
, next
) {
1489 vfio_release_domain(domain
, false);
1490 list_del(&domain
->next
);
1496 static int vfio_domains_have_iommu_cache(struct vfio_iommu
*iommu
)
1498 struct vfio_domain
*domain
;
1501 mutex_lock(&iommu
->lock
);
1502 list_for_each_entry(domain
, &iommu
->domain_list
, next
) {
1503 if (!(domain
->prot
& IOMMU_CACHE
)) {
1508 mutex_unlock(&iommu
->lock
);
1513 static long vfio_iommu_type1_ioctl(void *iommu_data
,
1514 unsigned int cmd
, unsigned long arg
)
1516 struct vfio_iommu
*iommu
= iommu_data
;
1517 unsigned long minsz
;
1519 if (cmd
== VFIO_CHECK_EXTENSION
) {
1521 case VFIO_TYPE1_IOMMU
:
1522 case VFIO_TYPE1v2_IOMMU
:
1523 case VFIO_TYPE1_NESTING_IOMMU
:
1525 case VFIO_DMA_CC_IOMMU
:
1528 return vfio_domains_have_iommu_cache(iommu
);
1532 } else if (cmd
== VFIO_IOMMU_GET_INFO
) {
1533 struct vfio_iommu_type1_info info
;
1535 minsz
= offsetofend(struct vfio_iommu_type1_info
, iova_pgsizes
);
1537 if (copy_from_user(&info
, (void __user
*)arg
, minsz
))
1540 if (info
.argsz
< minsz
)
1543 info
.flags
= VFIO_IOMMU_INFO_PGSIZES
;
1545 info
.iova_pgsizes
= vfio_pgsize_bitmap(iommu
);
1547 return copy_to_user((void __user
*)arg
, &info
, minsz
) ?
1550 } else if (cmd
== VFIO_IOMMU_MAP_DMA
) {
1551 struct vfio_iommu_type1_dma_map map
;
1552 uint32_t mask
= VFIO_DMA_MAP_FLAG_READ
|
1553 VFIO_DMA_MAP_FLAG_WRITE
;
1555 minsz
= offsetofend(struct vfio_iommu_type1_dma_map
, size
);
1557 if (copy_from_user(&map
, (void __user
*)arg
, minsz
))
1560 if (map
.argsz
< minsz
|| map
.flags
& ~mask
)
1563 return vfio_dma_do_map(iommu
, &map
);
1565 } else if (cmd
== VFIO_IOMMU_UNMAP_DMA
) {
1566 struct vfio_iommu_type1_dma_unmap unmap
;
1569 minsz
= offsetofend(struct vfio_iommu_type1_dma_unmap
, size
);
1571 if (copy_from_user(&unmap
, (void __user
*)arg
, minsz
))
1574 if (unmap
.argsz
< minsz
|| unmap
.flags
)
1577 ret
= vfio_dma_do_unmap(iommu
, &unmap
);
1581 return copy_to_user((void __user
*)arg
, &unmap
, minsz
) ?
1588 static int vfio_iommu_type1_register_notifier(void *iommu_data
,
1589 unsigned long *events
,
1590 struct notifier_block
*nb
)
1592 struct vfio_iommu
*iommu
= iommu_data
;
1594 /* clear known events */
1595 *events
&= ~VFIO_IOMMU_NOTIFY_DMA_UNMAP
;
1597 /* refuse to register if still events remaining */
1601 return blocking_notifier_chain_register(&iommu
->notifier
, nb
);
1604 static int vfio_iommu_type1_unregister_notifier(void *iommu_data
,
1605 struct notifier_block
*nb
)
1607 struct vfio_iommu
*iommu
= iommu_data
;
1609 return blocking_notifier_chain_unregister(&iommu
->notifier
, nb
);
1612 static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1
= {
1613 .name
= "vfio-iommu-type1",
1614 .owner
= THIS_MODULE
,
1615 .open
= vfio_iommu_type1_open
,
1616 .release
= vfio_iommu_type1_release
,
1617 .ioctl
= vfio_iommu_type1_ioctl
,
1618 .attach_group
= vfio_iommu_type1_attach_group
,
1619 .detach_group
= vfio_iommu_type1_detach_group
,
1620 .pin_pages
= vfio_iommu_type1_pin_pages
,
1621 .unpin_pages
= vfio_iommu_type1_unpin_pages
,
1622 .register_notifier
= vfio_iommu_type1_register_notifier
,
1623 .unregister_notifier
= vfio_iommu_type1_unregister_notifier
,
1626 static int __init
vfio_iommu_type1_init(void)
1628 return vfio_register_iommu_driver(&vfio_iommu_driver_ops_type1
);
1631 static void __exit
vfio_iommu_type1_cleanup(void)
1633 vfio_unregister_iommu_driver(&vfio_iommu_driver_ops_type1
);
1636 module_init(vfio_iommu_type1_init
);
1637 module_exit(vfio_iommu_type1_cleanup
);
1639 MODULE_VERSION(DRIVER_VERSION
);
1640 MODULE_LICENSE("GPL v2");
1641 MODULE_AUTHOR(DRIVER_AUTHOR
);
1642 MODULE_DESCRIPTION(DRIVER_DESC
);