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/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
);
250 struct mm_struct
*mm
;
252 struct work_struct work
;
255 /* delayed decrement/increment for locked_vm */
256 static void vfio_lock_acct_bg(struct work_struct
*work
)
258 struct vwork
*vwork
= container_of(work
, struct vwork
, work
);
259 struct mm_struct
*mm
;
262 down_write(&mm
->mmap_sem
);
263 mm
->locked_vm
+= vwork
->npage
;
264 up_write(&mm
->mmap_sem
);
269 static void vfio_lock_acct(struct task_struct
*task
, long npage
)
272 struct mm_struct
*mm
;
278 is_current
= (task
->mm
== current
->mm
);
280 mm
= is_current
? task
->mm
: get_task_mm(task
);
282 return; /* process exited */
284 if (down_write_trylock(&mm
->mmap_sem
)) {
285 mm
->locked_vm
+= npage
;
286 up_write(&mm
->mmap_sem
);
293 mm
= get_task_mm(task
);
299 * Couldn't get mmap_sem lock, so must setup to update
300 * mm->locked_vm later. If locked_vm were atomic, we
301 * wouldn't need this silliness
303 vwork
= kmalloc(sizeof(struct vwork
), GFP_KERNEL
);
304 if (WARN_ON(!vwork
)) {
308 INIT_WORK(&vwork
->work
, vfio_lock_acct_bg
);
310 vwork
->npage
= npage
;
311 schedule_work(&vwork
->work
);
315 * Some mappings aren't backed by a struct page, for example an mmap'd
316 * MMIO range for our own or another device. These use a different
317 * pfn conversion and shouldn't be tracked as locked pages.
319 static bool is_invalid_reserved_pfn(unsigned long pfn
)
321 if (pfn_valid(pfn
)) {
323 struct page
*tail
= pfn_to_page(pfn
);
324 struct page
*head
= compound_head(tail
);
325 reserved
= !!(PageReserved(head
));
328 * "head" is not a dangling pointer
329 * (compound_head takes care of that)
330 * but the hugepage may have been split
331 * from under us (and we may not hold a
332 * reference count on the head page so it can
333 * be reused before we run PageReferenced), so
334 * we've to check PageTail before returning
341 return PageReserved(tail
);
347 static int put_pfn(unsigned long pfn
, int prot
)
349 if (!is_invalid_reserved_pfn(pfn
)) {
350 struct page
*page
= pfn_to_page(pfn
);
351 if (prot
& IOMMU_WRITE
)
359 static int vaddr_get_pfn(struct mm_struct
*mm
, unsigned long vaddr
,
360 int prot
, unsigned long *pfn
)
362 struct page
*page
[1];
363 struct vm_area_struct
*vma
;
366 if (mm
== current
->mm
) {
367 ret
= get_user_pages_fast(vaddr
, 1, !!(prot
& IOMMU_WRITE
),
370 unsigned int flags
= 0;
372 if (prot
& IOMMU_WRITE
)
375 down_read(&mm
->mmap_sem
);
376 ret
= get_user_pages_remote(NULL
, mm
, vaddr
, 1, flags
, page
,
378 up_read(&mm
->mmap_sem
);
382 *pfn
= page_to_pfn(page
[0]);
386 down_read(&mm
->mmap_sem
);
388 vma
= find_vma_intersection(mm
, vaddr
, vaddr
+ 1);
390 if (vma
&& vma
->vm_flags
& VM_PFNMAP
) {
391 *pfn
= ((vaddr
- vma
->vm_start
) >> PAGE_SHIFT
) + vma
->vm_pgoff
;
392 if (is_invalid_reserved_pfn(*pfn
))
396 up_read(&mm
->mmap_sem
);
401 * Attempt to pin pages. We really don't want to track all the pfns and
402 * the iommu can only map chunks of consecutive pfns anyway, so get the
403 * first page and all consecutive pages with the same locking.
405 static long vfio_pin_pages_remote(struct vfio_dma
*dma
, unsigned long vaddr
,
406 long npage
, unsigned long *pfn_base
)
408 unsigned long limit
= rlimit(RLIMIT_MEMLOCK
) >> PAGE_SHIFT
;
409 bool lock_cap
= capable(CAP_IPC_LOCK
);
410 long ret
, pinned
= 0, lock_acct
= 0;
412 dma_addr_t iova
= vaddr
- dma
->vaddr
+ dma
->iova
;
414 /* This code path is only user initiated */
418 ret
= vaddr_get_pfn(current
->mm
, vaddr
, dma
->prot
, pfn_base
);
423 rsvd
= is_invalid_reserved_pfn(*pfn_base
);
426 * Reserved pages aren't counted against the user, externally pinned
427 * pages are already counted against the user.
429 if (!rsvd
&& !vfio_find_vpfn(dma
, iova
)) {
430 if (!lock_cap
&& current
->mm
->locked_vm
+ 1 > limit
) {
431 put_pfn(*pfn_base
, dma
->prot
);
432 pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n", __func__
,
433 limit
<< PAGE_SHIFT
);
439 if (unlikely(disable_hugepages
))
442 /* Lock all the consecutive pages from pfn_base */
443 for (vaddr
+= PAGE_SIZE
, iova
+= PAGE_SIZE
; pinned
< npage
;
444 pinned
++, vaddr
+= PAGE_SIZE
, iova
+= PAGE_SIZE
) {
445 unsigned long pfn
= 0;
447 ret
= vaddr_get_pfn(current
->mm
, vaddr
, dma
->prot
, &pfn
);
451 if (pfn
!= *pfn_base
+ pinned
||
452 rsvd
!= is_invalid_reserved_pfn(pfn
)) {
453 put_pfn(pfn
, dma
->prot
);
457 if (!rsvd
&& !vfio_find_vpfn(dma
, iova
)) {
459 current
->mm
->locked_vm
+ lock_acct
+ 1 > limit
) {
460 put_pfn(pfn
, dma
->prot
);
461 pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n",
462 __func__
, limit
<< PAGE_SHIFT
);
470 vfio_lock_acct(current
, lock_acct
);
475 static long vfio_unpin_pages_remote(struct vfio_dma
*dma
, dma_addr_t iova
,
476 unsigned long pfn
, long npage
,
479 long unlocked
= 0, locked
= 0;
482 for (i
= 0; i
< npage
; i
++, iova
+= PAGE_SIZE
) {
483 if (put_pfn(pfn
++, dma
->prot
)) {
485 if (vfio_find_vpfn(dma
, iova
))
491 vfio_lock_acct(dma
->task
, locked
- unlocked
);
496 static int vfio_pin_page_external(struct vfio_dma
*dma
, unsigned long vaddr
,
497 unsigned long *pfn_base
, bool do_accounting
)
500 bool lock_cap
= has_capability(dma
->task
, CAP_IPC_LOCK
);
501 struct mm_struct
*mm
;
505 mm
= get_task_mm(dma
->task
);
509 ret
= vaddr_get_pfn(mm
, vaddr
, dma
->prot
, pfn_base
);
513 rsvd
= is_invalid_reserved_pfn(*pfn_base
);
514 limit
= task_rlimit(dma
->task
, RLIMIT_MEMLOCK
) >> PAGE_SHIFT
;
516 if (!rsvd
&& !lock_cap
&& mm
->locked_vm
+ 1 > limit
) {
517 put_pfn(*pfn_base
, dma
->prot
);
518 pr_warn("%s: Task %s (%d) RLIMIT_MEMLOCK (%ld) exceeded\n",
519 __func__
, dma
->task
->comm
, task_pid_nr(dma
->task
),
520 limit
<< PAGE_SHIFT
);
525 if (!rsvd
&& do_accounting
)
526 vfio_lock_acct(dma
->task
, 1);
534 static int vfio_unpin_page_external(struct vfio_dma
*dma
, dma_addr_t iova
,
538 struct vfio_pfn
*vpfn
= vfio_find_vpfn(dma
, iova
);
543 unlocked
= vfio_iova_put_vfio_pfn(dma
, vpfn
);
546 vfio_lock_acct(dma
->task
, -unlocked
);
551 static int vfio_iommu_type1_pin_pages(void *iommu_data
,
552 unsigned long *user_pfn
,
554 unsigned long *phys_pfn
)
556 struct vfio_iommu
*iommu
= iommu_data
;
558 unsigned long remote_vaddr
;
559 struct vfio_dma
*dma
;
562 if (!iommu
|| !user_pfn
|| !phys_pfn
)
565 /* Supported for v2 version only */
569 mutex_lock(&iommu
->lock
);
571 /* Fail if notifier list is empty */
572 if ((!iommu
->external_domain
) || (!iommu
->notifier
.head
)) {
578 * If iommu capable domain exist in the container then all pages are
579 * already pinned and accounted. Accouting should be done if there is no
580 * iommu capable domain in the container.
582 do_accounting
= !IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu
);
584 for (i
= 0; i
< npage
; i
++) {
586 struct vfio_pfn
*vpfn
;
588 iova
= user_pfn
[i
] << PAGE_SHIFT
;
589 dma
= vfio_find_dma(iommu
, iova
, PAGE_SIZE
);
595 if ((dma
->prot
& prot
) != prot
) {
600 vpfn
= vfio_iova_get_vfio_pfn(dma
, iova
);
602 phys_pfn
[i
] = vpfn
->pfn
;
606 remote_vaddr
= dma
->vaddr
+ iova
- dma
->iova
;
607 ret
= vfio_pin_page_external(dma
, remote_vaddr
, &phys_pfn
[i
],
614 ret
= vfio_add_to_pfn_list(dma
, iova
, phys_pfn
[i
]);
616 vfio_unpin_page_external(dma
, iova
, do_accounting
);
626 for (j
= 0; j
< i
; j
++) {
629 iova
= user_pfn
[j
] << PAGE_SHIFT
;
630 dma
= vfio_find_dma(iommu
, iova
, PAGE_SIZE
);
631 vfio_unpin_page_external(dma
, iova
, do_accounting
);
635 mutex_unlock(&iommu
->lock
);
639 static int vfio_iommu_type1_unpin_pages(void *iommu_data
,
640 unsigned long *user_pfn
,
643 struct vfio_iommu
*iommu
= iommu_data
;
647 if (!iommu
|| !user_pfn
)
650 /* Supported for v2 version only */
654 mutex_lock(&iommu
->lock
);
656 if (!iommu
->external_domain
) {
657 mutex_unlock(&iommu
->lock
);
661 do_accounting
= !IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu
);
662 for (i
= 0; i
< npage
; i
++) {
663 struct vfio_dma
*dma
;
666 iova
= user_pfn
[i
] << PAGE_SHIFT
;
667 dma
= vfio_find_dma(iommu
, iova
, PAGE_SIZE
);
670 vfio_unpin_page_external(dma
, iova
, do_accounting
);
674 mutex_unlock(&iommu
->lock
);
675 return i
> npage
? npage
: (i
> 0 ? i
: -EINVAL
);
678 static long vfio_unmap_unpin(struct vfio_iommu
*iommu
, struct vfio_dma
*dma
,
681 dma_addr_t iova
= dma
->iova
, end
= dma
->iova
+ dma
->size
;
682 struct vfio_domain
*domain
, *d
;
688 if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu
))
692 * We use the IOMMU to track the physical addresses, otherwise we'd
693 * need a much more complicated tracking system. Unfortunately that
694 * means we need to use one of the iommu domains to figure out the
695 * pfns to unpin. The rest need to be unmapped in advance so we have
696 * no iommu translations remaining when the pages are unpinned.
698 domain
= d
= list_first_entry(&iommu
->domain_list
,
699 struct vfio_domain
, next
);
701 list_for_each_entry_continue(d
, &iommu
->domain_list
, next
) {
702 iommu_unmap(d
->domain
, dma
->iova
, dma
->size
);
707 size_t unmapped
, len
;
708 phys_addr_t phys
, next
;
710 phys
= iommu_iova_to_phys(domain
->domain
, iova
);
711 if (WARN_ON(!phys
)) {
717 * To optimize for fewer iommu_unmap() calls, each of which
718 * may require hardware cache flushing, try to find the
719 * largest contiguous physical memory chunk to unmap.
721 for (len
= PAGE_SIZE
;
722 !domain
->fgsp
&& iova
+ len
< end
; len
+= PAGE_SIZE
) {
723 next
= iommu_iova_to_phys(domain
->domain
, iova
+ len
);
724 if (next
!= phys
+ len
)
728 unmapped
= iommu_unmap(domain
->domain
, iova
, len
);
729 if (WARN_ON(!unmapped
))
732 unlocked
+= vfio_unpin_pages_remote(dma
, iova
,
734 unmapped
>> PAGE_SHIFT
,
741 dma
->iommu_mapped
= false;
743 vfio_lock_acct(dma
->task
, -unlocked
);
749 static void vfio_remove_dma(struct vfio_iommu
*iommu
, struct vfio_dma
*dma
)
751 vfio_unmap_unpin(iommu
, dma
, true);
752 vfio_unlink_dma(iommu
, dma
);
753 put_task_struct(dma
->task
);
757 static unsigned long vfio_pgsize_bitmap(struct vfio_iommu
*iommu
)
759 struct vfio_domain
*domain
;
760 unsigned long bitmap
= ULONG_MAX
;
762 mutex_lock(&iommu
->lock
);
763 list_for_each_entry(domain
, &iommu
->domain_list
, next
)
764 bitmap
&= domain
->domain
->pgsize_bitmap
;
765 mutex_unlock(&iommu
->lock
);
768 * In case the IOMMU supports page sizes smaller than PAGE_SIZE
769 * we pretend PAGE_SIZE is supported and hide sub-PAGE_SIZE sizes.
770 * That way the user will be able to map/unmap buffers whose size/
771 * start address is aligned with PAGE_SIZE. Pinning code uses that
772 * granularity while iommu driver can use the sub-PAGE_SIZE size
775 if (bitmap
& ~PAGE_MASK
) {
783 static int vfio_dma_do_unmap(struct vfio_iommu
*iommu
,
784 struct vfio_iommu_type1_dma_unmap
*unmap
)
787 struct vfio_dma
*dma
, *dma_last
= NULL
;
789 int ret
= 0, retries
= 0;
791 mask
= ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu
))) - 1;
793 if (unmap
->iova
& mask
)
795 if (!unmap
->size
|| unmap
->size
& mask
)
798 WARN_ON(mask
& PAGE_MASK
);
800 mutex_lock(&iommu
->lock
);
803 * vfio-iommu-type1 (v1) - User mappings were coalesced together to
804 * avoid tracking individual mappings. This means that the granularity
805 * of the original mapping was lost and the user was allowed to attempt
806 * to unmap any range. Depending on the contiguousness of physical
807 * memory and page sizes supported by the IOMMU, arbitrary unmaps may
808 * or may not have worked. We only guaranteed unmap granularity
809 * matching the original mapping; even though it was untracked here,
810 * the original mappings are reflected in IOMMU mappings. This
811 * resulted in a couple unusual behaviors. First, if a range is not
812 * able to be unmapped, ex. a set of 4k pages that was mapped as a
813 * 2M hugepage into the IOMMU, the unmap ioctl returns success but with
814 * a zero sized unmap. Also, if an unmap request overlaps the first
815 * address of a hugepage, the IOMMU will unmap the entire hugepage.
816 * This also returns success and the returned unmap size reflects the
817 * actual size unmapped.
819 * We attempt to maintain compatibility with this "v1" interface, but
820 * we take control out of the hands of the IOMMU. Therefore, an unmap
821 * request offset from the beginning of the original mapping will
822 * return success with zero sized unmap. And an unmap request covering
823 * the first iova of mapping will unmap the entire range.
825 * The v2 version of this interface intends to be more deterministic.
826 * Unmap requests must fully cover previous mappings. Multiple
827 * mappings may still be unmaped by specifying large ranges, but there
828 * must not be any previous mappings bisected by the range. An error
829 * will be returned if these conditions are not met. The v2 interface
830 * will only return success and a size of zero if there were no
831 * mappings within the range.
834 dma
= vfio_find_dma(iommu
, unmap
->iova
, 1);
835 if (dma
&& dma
->iova
!= unmap
->iova
) {
839 dma
= vfio_find_dma(iommu
, unmap
->iova
+ unmap
->size
- 1, 0);
840 if (dma
&& dma
->iova
+ dma
->size
!= unmap
->iova
+ unmap
->size
) {
846 while ((dma
= vfio_find_dma(iommu
, unmap
->iova
, unmap
->size
))) {
847 if (!iommu
->v2
&& unmap
->iova
> dma
->iova
)
850 * Task with same address space who mapped this iova range is
851 * allowed to unmap the iova range.
853 if (dma
->task
->mm
!= current
->mm
)
856 if (!RB_EMPTY_ROOT(&dma
->pfn_list
)) {
857 struct vfio_iommu_type1_dma_unmap nb_unmap
;
859 if (dma_last
== dma
) {
860 BUG_ON(++retries
> 10);
866 nb_unmap
.iova
= dma
->iova
;
867 nb_unmap
.size
= dma
->size
;
870 * Notify anyone (mdev vendor drivers) to invalidate and
871 * unmap iovas within the range we're about to unmap.
872 * Vendor drivers MUST unpin pages in response to an
875 mutex_unlock(&iommu
->lock
);
876 blocking_notifier_call_chain(&iommu
->notifier
,
877 VFIO_IOMMU_NOTIFY_DMA_UNMAP
,
881 unmapped
+= dma
->size
;
882 vfio_remove_dma(iommu
, dma
);
886 mutex_unlock(&iommu
->lock
);
888 /* Report how much was unmapped */
889 unmap
->size
= unmapped
;
895 * Turns out AMD IOMMU has a page table bug where it won't map large pages
896 * to a region that previously mapped smaller pages. This should be fixed
897 * soon, so this is just a temporary workaround to break mappings down into
898 * PAGE_SIZE. Better to map smaller pages than nothing.
900 static int map_try_harder(struct vfio_domain
*domain
, dma_addr_t iova
,
901 unsigned long pfn
, long npage
, int prot
)
906 for (i
= 0; i
< npage
; i
++, pfn
++, iova
+= PAGE_SIZE
) {
907 ret
= iommu_map(domain
->domain
, iova
,
908 (phys_addr_t
)pfn
<< PAGE_SHIFT
,
909 PAGE_SIZE
, prot
| domain
->prot
);
914 for (; i
< npage
&& i
> 0; i
--, iova
-= PAGE_SIZE
)
915 iommu_unmap(domain
->domain
, iova
, PAGE_SIZE
);
920 static int vfio_iommu_map(struct vfio_iommu
*iommu
, dma_addr_t iova
,
921 unsigned long pfn
, long npage
, int prot
)
923 struct vfio_domain
*d
;
926 list_for_each_entry(d
, &iommu
->domain_list
, next
) {
927 ret
= iommu_map(d
->domain
, iova
, (phys_addr_t
)pfn
<< PAGE_SHIFT
,
928 npage
<< PAGE_SHIFT
, prot
| d
->prot
);
931 map_try_harder(d
, iova
, pfn
, npage
, prot
))
941 list_for_each_entry_continue_reverse(d
, &iommu
->domain_list
, next
)
942 iommu_unmap(d
->domain
, iova
, npage
<< PAGE_SHIFT
);
947 static int vfio_pin_map_dma(struct vfio_iommu
*iommu
, struct vfio_dma
*dma
,
950 dma_addr_t iova
= dma
->iova
;
951 unsigned long vaddr
= dma
->vaddr
;
952 size_t size
= map_size
;
958 /* Pin a contiguous chunk of memory */
959 npage
= vfio_pin_pages_remote(dma
, vaddr
+ dma
->size
,
960 size
>> PAGE_SHIFT
, &pfn
);
968 ret
= vfio_iommu_map(iommu
, iova
+ dma
->size
, pfn
, npage
,
971 vfio_unpin_pages_remote(dma
, iova
+ dma
->size
, pfn
,
976 size
-= npage
<< PAGE_SHIFT
;
977 dma
->size
+= npage
<< PAGE_SHIFT
;
980 dma
->iommu_mapped
= true;
983 vfio_remove_dma(iommu
, dma
);
988 static int vfio_dma_do_map(struct vfio_iommu
*iommu
,
989 struct vfio_iommu_type1_dma_map
*map
)
991 dma_addr_t iova
= map
->iova
;
992 unsigned long vaddr
= map
->vaddr
;
993 size_t size
= map
->size
;
994 int ret
= 0, prot
= 0;
996 struct vfio_dma
*dma
;
998 /* Verify that none of our __u64 fields overflow */
999 if (map
->size
!= size
|| map
->vaddr
!= vaddr
|| map
->iova
!= iova
)
1002 mask
= ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu
))) - 1;
1004 WARN_ON(mask
& PAGE_MASK
);
1006 /* READ/WRITE from device perspective */
1007 if (map
->flags
& VFIO_DMA_MAP_FLAG_WRITE
)
1008 prot
|= IOMMU_WRITE
;
1009 if (map
->flags
& VFIO_DMA_MAP_FLAG_READ
)
1012 if (!prot
|| !size
|| (size
| iova
| vaddr
) & mask
)
1015 /* Don't allow IOVA or virtual address wrap */
1016 if (iova
+ size
- 1 < iova
|| vaddr
+ size
- 1 < vaddr
)
1019 mutex_lock(&iommu
->lock
);
1021 if (vfio_find_dma(iommu
, iova
, size
)) {
1026 dma
= kzalloc(sizeof(*dma
), GFP_KERNEL
);
1035 get_task_struct(current
);
1036 dma
->task
= current
;
1037 dma
->pfn_list
= RB_ROOT
;
1039 /* Insert zero-sized and grow as we map chunks of it */
1040 vfio_link_dma(iommu
, dma
);
1042 /* Don't pin and map if container doesn't contain IOMMU capable domain*/
1043 if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu
))
1046 ret
= vfio_pin_map_dma(iommu
, dma
, size
);
1049 mutex_unlock(&iommu
->lock
);
1053 static int vfio_bus_type(struct device
*dev
, void *data
)
1055 struct bus_type
**bus
= data
;
1057 if (*bus
&& *bus
!= dev
->bus
)
1065 static int vfio_iommu_replay(struct vfio_iommu
*iommu
,
1066 struct vfio_domain
*domain
)
1068 struct vfio_domain
*d
;
1072 /* Arbitrarily pick the first domain in the list for lookups */
1073 d
= list_first_entry(&iommu
->domain_list
, struct vfio_domain
, next
);
1074 n
= rb_first(&iommu
->dma_list
);
1076 for (; n
; n
= rb_next(n
)) {
1077 struct vfio_dma
*dma
;
1080 dma
= rb_entry(n
, struct vfio_dma
, node
);
1083 while (iova
< dma
->iova
+ dma
->size
) {
1087 if (dma
->iommu_mapped
) {
1091 phys
= iommu_iova_to_phys(d
->domain
, iova
);
1093 if (WARN_ON(!phys
)) {
1101 while (i
< dma
->iova
+ dma
->size
&&
1102 p
== iommu_iova_to_phys(d
->domain
, i
)) {
1109 unsigned long vaddr
= dma
->vaddr
+
1111 size_t n
= dma
->iova
+ dma
->size
- iova
;
1114 npage
= vfio_pin_pages_remote(dma
, vaddr
,
1123 phys
= pfn
<< PAGE_SHIFT
;
1124 size
= npage
<< PAGE_SHIFT
;
1127 ret
= iommu_map(domain
->domain
, iova
, phys
,
1128 size
, dma
->prot
| domain
->prot
);
1134 dma
->iommu_mapped
= true;
1140 * We change our unmap behavior slightly depending on whether the IOMMU
1141 * supports fine-grained superpages. IOMMUs like AMD-Vi will use a superpage
1142 * for practically any contiguous power-of-two mapping we give it. This means
1143 * we don't need to look for contiguous chunks ourselves to make unmapping
1144 * more efficient. On IOMMUs with coarse-grained super pages, like Intel VT-d
1145 * with discrete 2M/1G/512G/1T superpages, identifying contiguous chunks
1146 * significantly boosts non-hugetlbfs mappings and doesn't seem to hurt when
1147 * hugetlbfs is in use.
1149 static void vfio_test_domain_fgsp(struct vfio_domain
*domain
)
1152 int ret
, order
= get_order(PAGE_SIZE
* 2);
1154 pages
= alloc_pages(GFP_KERNEL
| __GFP_ZERO
, order
);
1158 ret
= iommu_map(domain
->domain
, 0, page_to_phys(pages
), PAGE_SIZE
* 2,
1159 IOMMU_READ
| IOMMU_WRITE
| domain
->prot
);
1161 size_t unmapped
= iommu_unmap(domain
->domain
, 0, PAGE_SIZE
);
1163 if (unmapped
== PAGE_SIZE
)
1164 iommu_unmap(domain
->domain
, PAGE_SIZE
, PAGE_SIZE
);
1166 domain
->fgsp
= true;
1169 __free_pages(pages
, order
);
1172 static struct vfio_group
*find_iommu_group(struct vfio_domain
*domain
,
1173 struct iommu_group
*iommu_group
)
1175 struct vfio_group
*g
;
1177 list_for_each_entry(g
, &domain
->group_list
, next
) {
1178 if (g
->iommu_group
== iommu_group
)
1185 static bool vfio_iommu_has_resv_msi(struct iommu_group
*group
,
1188 struct list_head group_resv_regions
;
1189 struct iommu_resv_region
*region
, *next
;
1192 INIT_LIST_HEAD(&group_resv_regions
);
1193 iommu_get_group_resv_regions(group
, &group_resv_regions
);
1194 list_for_each_entry(region
, &group_resv_regions
, list
) {
1195 if (region
->type
& IOMMU_RESV_MSI
) {
1196 *base
= region
->start
;
1202 list_for_each_entry_safe(region
, next
, &group_resv_regions
, list
)
1207 static int vfio_iommu_type1_attach_group(void *iommu_data
,
1208 struct iommu_group
*iommu_group
)
1210 struct vfio_iommu
*iommu
= iommu_data
;
1211 struct vfio_group
*group
;
1212 struct vfio_domain
*domain
, *d
;
1213 struct bus_type
*bus
= NULL
, *mdev_bus
;
1215 bool resv_msi
, msi_remap
;
1216 phys_addr_t resv_msi_base
;
1218 mutex_lock(&iommu
->lock
);
1220 list_for_each_entry(d
, &iommu
->domain_list
, next
) {
1221 if (find_iommu_group(d
, iommu_group
)) {
1222 mutex_unlock(&iommu
->lock
);
1227 if (iommu
->external_domain
) {
1228 if (find_iommu_group(iommu
->external_domain
, iommu_group
)) {
1229 mutex_unlock(&iommu
->lock
);
1234 group
= kzalloc(sizeof(*group
), GFP_KERNEL
);
1235 domain
= kzalloc(sizeof(*domain
), GFP_KERNEL
);
1236 if (!group
|| !domain
) {
1241 group
->iommu_group
= iommu_group
;
1243 /* Determine bus_type in order to allocate a domain */
1244 ret
= iommu_group_for_each_dev(iommu_group
, &bus
, vfio_bus_type
);
1248 mdev_bus
= symbol_get(mdev_bus_type
);
1251 if ((bus
== mdev_bus
) && !iommu_present(bus
)) {
1252 symbol_put(mdev_bus_type
);
1253 if (!iommu
->external_domain
) {
1254 INIT_LIST_HEAD(&domain
->group_list
);
1255 iommu
->external_domain
= domain
;
1259 list_add(&group
->next
,
1260 &iommu
->external_domain
->group_list
);
1261 mutex_unlock(&iommu
->lock
);
1264 symbol_put(mdev_bus_type
);
1267 domain
->domain
= iommu_domain_alloc(bus
);
1268 if (!domain
->domain
) {
1273 if (iommu
->nesting
) {
1276 ret
= iommu_domain_set_attr(domain
->domain
, DOMAIN_ATTR_NESTING
,
1282 ret
= iommu_attach_group(domain
->domain
, iommu_group
);
1286 resv_msi
= vfio_iommu_has_resv_msi(iommu_group
, &resv_msi_base
);
1288 INIT_LIST_HEAD(&domain
->group_list
);
1289 list_add(&group
->next
, &domain
->group_list
);
1291 msi_remap
= resv_msi
? irq_domain_check_msi_remap() :
1292 iommu_capable(bus
, IOMMU_CAP_INTR_REMAP
);
1294 if (!allow_unsafe_interrupts
&& !msi_remap
) {
1295 pr_warn("%s: No interrupt remapping support. Use the module param \"allow_unsafe_interrupts\" to enable VFIO IOMMU support on this platform\n",
1301 if (iommu_capable(bus
, IOMMU_CAP_CACHE_COHERENCY
))
1302 domain
->prot
|= IOMMU_CACHE
;
1305 * Try to match an existing compatible domain. We don't want to
1306 * preclude an IOMMU driver supporting multiple bus_types and being
1307 * able to include different bus_types in the same IOMMU domain, so
1308 * we test whether the domains use the same iommu_ops rather than
1309 * testing if they're on the same bus_type.
1311 list_for_each_entry(d
, &iommu
->domain_list
, next
) {
1312 if (d
->domain
->ops
== domain
->domain
->ops
&&
1313 d
->prot
== domain
->prot
) {
1314 iommu_detach_group(domain
->domain
, iommu_group
);
1315 if (!iommu_attach_group(d
->domain
, iommu_group
)) {
1316 list_add(&group
->next
, &d
->group_list
);
1317 iommu_domain_free(domain
->domain
);
1319 mutex_unlock(&iommu
->lock
);
1323 ret
= iommu_attach_group(domain
->domain
, iommu_group
);
1329 vfio_test_domain_fgsp(domain
);
1331 /* replay mappings on new domains */
1332 ret
= vfio_iommu_replay(iommu
, domain
);
1337 ret
= iommu_get_msi_cookie(domain
->domain
, resv_msi_base
);
1342 list_add(&domain
->next
, &iommu
->domain_list
);
1344 mutex_unlock(&iommu
->lock
);
1349 iommu_detach_group(domain
->domain
, iommu_group
);
1351 iommu_domain_free(domain
->domain
);
1355 mutex_unlock(&iommu
->lock
);
1359 static void vfio_iommu_unmap_unpin_all(struct vfio_iommu
*iommu
)
1361 struct rb_node
*node
;
1363 while ((node
= rb_first(&iommu
->dma_list
)))
1364 vfio_remove_dma(iommu
, rb_entry(node
, struct vfio_dma
, node
));
1367 static void vfio_iommu_unmap_unpin_reaccount(struct vfio_iommu
*iommu
)
1369 struct rb_node
*n
, *p
;
1371 n
= rb_first(&iommu
->dma_list
);
1372 for (; n
; n
= rb_next(n
)) {
1373 struct vfio_dma
*dma
;
1374 long locked
= 0, unlocked
= 0;
1376 dma
= rb_entry(n
, struct vfio_dma
, node
);
1377 unlocked
+= vfio_unmap_unpin(iommu
, dma
, false);
1378 p
= rb_first(&dma
->pfn_list
);
1379 for (; p
; p
= rb_next(p
)) {
1380 struct vfio_pfn
*vpfn
= rb_entry(p
, struct vfio_pfn
,
1383 if (!is_invalid_reserved_pfn(vpfn
->pfn
))
1386 vfio_lock_acct(dma
->task
, locked
- unlocked
);
1390 static void vfio_sanity_check_pfn_list(struct vfio_iommu
*iommu
)
1394 n
= rb_first(&iommu
->dma_list
);
1395 for (; n
; n
= rb_next(n
)) {
1396 struct vfio_dma
*dma
;
1398 dma
= rb_entry(n
, struct vfio_dma
, node
);
1400 if (WARN_ON(!RB_EMPTY_ROOT(&dma
->pfn_list
)))
1403 /* mdev vendor driver must unregister notifier */
1404 WARN_ON(iommu
->notifier
.head
);
1407 static void vfio_iommu_type1_detach_group(void *iommu_data
,
1408 struct iommu_group
*iommu_group
)
1410 struct vfio_iommu
*iommu
= iommu_data
;
1411 struct vfio_domain
*domain
;
1412 struct vfio_group
*group
;
1414 mutex_lock(&iommu
->lock
);
1416 if (iommu
->external_domain
) {
1417 group
= find_iommu_group(iommu
->external_domain
, iommu_group
);
1419 list_del(&group
->next
);
1422 if (list_empty(&iommu
->external_domain
->group_list
)) {
1423 vfio_sanity_check_pfn_list(iommu
);
1425 if (!IS_IOMMU_CAP_DOMAIN_IN_CONTAINER(iommu
))
1426 vfio_iommu_unmap_unpin_all(iommu
);
1428 kfree(iommu
->external_domain
);
1429 iommu
->external_domain
= NULL
;
1431 goto detach_group_done
;
1435 list_for_each_entry(domain
, &iommu
->domain_list
, next
) {
1436 group
= find_iommu_group(domain
, iommu_group
);
1440 iommu_detach_group(domain
->domain
, iommu_group
);
1441 list_del(&group
->next
);
1444 * Group ownership provides privilege, if the group list is
1445 * empty, the domain goes away. If it's the last domain with
1446 * iommu and external domain doesn't exist, then all the
1447 * mappings go away too. If it's the last domain with iommu and
1448 * external domain exist, update accounting
1450 if (list_empty(&domain
->group_list
)) {
1451 if (list_is_singular(&iommu
->domain_list
)) {
1452 if (!iommu
->external_domain
)
1453 vfio_iommu_unmap_unpin_all(iommu
);
1455 vfio_iommu_unmap_unpin_reaccount(iommu
);
1457 iommu_domain_free(domain
->domain
);
1458 list_del(&domain
->next
);
1465 mutex_unlock(&iommu
->lock
);
1468 static void *vfio_iommu_type1_open(unsigned long arg
)
1470 struct vfio_iommu
*iommu
;
1472 iommu
= kzalloc(sizeof(*iommu
), GFP_KERNEL
);
1474 return ERR_PTR(-ENOMEM
);
1477 case VFIO_TYPE1_IOMMU
:
1479 case VFIO_TYPE1_NESTING_IOMMU
:
1480 iommu
->nesting
= true;
1481 case VFIO_TYPE1v2_IOMMU
:
1486 return ERR_PTR(-EINVAL
);
1489 INIT_LIST_HEAD(&iommu
->domain_list
);
1490 iommu
->dma_list
= RB_ROOT
;
1491 mutex_init(&iommu
->lock
);
1492 BLOCKING_INIT_NOTIFIER_HEAD(&iommu
->notifier
);
1497 static void vfio_release_domain(struct vfio_domain
*domain
, bool external
)
1499 struct vfio_group
*group
, *group_tmp
;
1501 list_for_each_entry_safe(group
, group_tmp
,
1502 &domain
->group_list
, next
) {
1504 iommu_detach_group(domain
->domain
, group
->iommu_group
);
1505 list_del(&group
->next
);
1510 iommu_domain_free(domain
->domain
);
1513 static void vfio_iommu_type1_release(void *iommu_data
)
1515 struct vfio_iommu
*iommu
= iommu_data
;
1516 struct vfio_domain
*domain
, *domain_tmp
;
1518 if (iommu
->external_domain
) {
1519 vfio_release_domain(iommu
->external_domain
, true);
1520 vfio_sanity_check_pfn_list(iommu
);
1521 kfree(iommu
->external_domain
);
1524 vfio_iommu_unmap_unpin_all(iommu
);
1526 list_for_each_entry_safe(domain
, domain_tmp
,
1527 &iommu
->domain_list
, next
) {
1528 vfio_release_domain(domain
, false);
1529 list_del(&domain
->next
);
1535 static int vfio_domains_have_iommu_cache(struct vfio_iommu
*iommu
)
1537 struct vfio_domain
*domain
;
1540 mutex_lock(&iommu
->lock
);
1541 list_for_each_entry(domain
, &iommu
->domain_list
, next
) {
1542 if (!(domain
->prot
& IOMMU_CACHE
)) {
1547 mutex_unlock(&iommu
->lock
);
1552 static long vfio_iommu_type1_ioctl(void *iommu_data
,
1553 unsigned int cmd
, unsigned long arg
)
1555 struct vfio_iommu
*iommu
= iommu_data
;
1556 unsigned long minsz
;
1558 if (cmd
== VFIO_CHECK_EXTENSION
) {
1560 case VFIO_TYPE1_IOMMU
:
1561 case VFIO_TYPE1v2_IOMMU
:
1562 case VFIO_TYPE1_NESTING_IOMMU
:
1564 case VFIO_DMA_CC_IOMMU
:
1567 return vfio_domains_have_iommu_cache(iommu
);
1571 } else if (cmd
== VFIO_IOMMU_GET_INFO
) {
1572 struct vfio_iommu_type1_info info
;
1574 minsz
= offsetofend(struct vfio_iommu_type1_info
, iova_pgsizes
);
1576 if (copy_from_user(&info
, (void __user
*)arg
, minsz
))
1579 if (info
.argsz
< minsz
)
1582 info
.flags
= VFIO_IOMMU_INFO_PGSIZES
;
1584 info
.iova_pgsizes
= vfio_pgsize_bitmap(iommu
);
1586 return copy_to_user((void __user
*)arg
, &info
, minsz
) ?
1589 } else if (cmd
== VFIO_IOMMU_MAP_DMA
) {
1590 struct vfio_iommu_type1_dma_map map
;
1591 uint32_t mask
= VFIO_DMA_MAP_FLAG_READ
|
1592 VFIO_DMA_MAP_FLAG_WRITE
;
1594 minsz
= offsetofend(struct vfio_iommu_type1_dma_map
, size
);
1596 if (copy_from_user(&map
, (void __user
*)arg
, minsz
))
1599 if (map
.argsz
< minsz
|| map
.flags
& ~mask
)
1602 return vfio_dma_do_map(iommu
, &map
);
1604 } else if (cmd
== VFIO_IOMMU_UNMAP_DMA
) {
1605 struct vfio_iommu_type1_dma_unmap unmap
;
1608 minsz
= offsetofend(struct vfio_iommu_type1_dma_unmap
, size
);
1610 if (copy_from_user(&unmap
, (void __user
*)arg
, minsz
))
1613 if (unmap
.argsz
< minsz
|| unmap
.flags
)
1616 ret
= vfio_dma_do_unmap(iommu
, &unmap
);
1620 return copy_to_user((void __user
*)arg
, &unmap
, minsz
) ?
1627 static int vfio_iommu_type1_register_notifier(void *iommu_data
,
1628 unsigned long *events
,
1629 struct notifier_block
*nb
)
1631 struct vfio_iommu
*iommu
= iommu_data
;
1633 /* clear known events */
1634 *events
&= ~VFIO_IOMMU_NOTIFY_DMA_UNMAP
;
1636 /* refuse to register if still events remaining */
1640 return blocking_notifier_chain_register(&iommu
->notifier
, nb
);
1643 static int vfio_iommu_type1_unregister_notifier(void *iommu_data
,
1644 struct notifier_block
*nb
)
1646 struct vfio_iommu
*iommu
= iommu_data
;
1648 return blocking_notifier_chain_unregister(&iommu
->notifier
, nb
);
1651 static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1
= {
1652 .name
= "vfio-iommu-type1",
1653 .owner
= THIS_MODULE
,
1654 .open
= vfio_iommu_type1_open
,
1655 .release
= vfio_iommu_type1_release
,
1656 .ioctl
= vfio_iommu_type1_ioctl
,
1657 .attach_group
= vfio_iommu_type1_attach_group
,
1658 .detach_group
= vfio_iommu_type1_detach_group
,
1659 .pin_pages
= vfio_iommu_type1_pin_pages
,
1660 .unpin_pages
= vfio_iommu_type1_unpin_pages
,
1661 .register_notifier
= vfio_iommu_type1_register_notifier
,
1662 .unregister_notifier
= vfio_iommu_type1_unregister_notifier
,
1665 static int __init
vfio_iommu_type1_init(void)
1667 return vfio_register_iommu_driver(&vfio_iommu_driver_ops_type1
);
1670 static void __exit
vfio_iommu_type1_cleanup(void)
1672 vfio_unregister_iommu_driver(&vfio_iommu_driver_ops_type1
);
1675 module_init(vfio_iommu_type1_init
);
1676 module_exit(vfio_iommu_type1_cleanup
);
1678 MODULE_VERSION(DRIVER_VERSION
);
1679 MODULE_LICENSE("GPL v2");
1680 MODULE_AUTHOR(DRIVER_AUTHOR
);
1681 MODULE_DESCRIPTION(DRIVER_DESC
);