1 What: /sys/kernel/iommu_groups/ 1 What: /sys/kernel/iommu_groups/
2 Date: May 2012 2 Date: May 2012
3 KernelVersion: v3.5 3 KernelVersion: v3.5
4 Contact: Alex Williamson <alex.williamso 4 Contact: Alex Williamson <alex.williamson@redhat.com>
5 Description: /sys/kernel/iommu_groups/ cont 5 Description: /sys/kernel/iommu_groups/ contains a number of sub-
6 directories, each representing 6 directories, each representing an IOMMU group. The
7 name of the sub-directory matc 7 name of the sub-directory matches the iommu_group_id()
8 for the group, which is an int 8 for the group, which is an integer value. Within each
9 subdirectory is another direct 9 subdirectory is another directory named "devices" with
10 links to the sysfs devices con 10 links to the sysfs devices contained in this group.
11 The group directory also optio 11 The group directory also optionally contains a "name"
12 file if the IOMMU driver has c 12 file if the IOMMU driver has chosen to register a more
13 common name for the group. 13 common name for the group.
14 Users: 14 Users:
15 15
16 What: /sys/kernel/iommu_groups/reser 16 What: /sys/kernel/iommu_groups/reserved_regions
17 Date: January 2017 17 Date: January 2017
18 KernelVersion: v4.11 18 KernelVersion: v4.11
19 Contact: Eric Auger <eric.auger@redhat.c 19 Contact: Eric Auger <eric.auger@redhat.com>
20 Description: /sys/kernel/iommu_groups/reser 20 Description: /sys/kernel/iommu_groups/reserved_regions list IOVA
21 regions that are reserved. Not 21 regions that are reserved. Not necessarily all
22 reserved regions are listed. T 22 reserved regions are listed. This is typically used to
23 output direct-mapped, MSI, non 23 output direct-mapped, MSI, non mappable regions. Each
24 region is described on a singl 24 region is described on a single line: the 1st field is
25 the base IOVA, the second is t 25 the base IOVA, the second is the end IOVA and the third
26 field describes the type of th 26 field describes the type of the region.
27 <<
28 Since kernel 5.3, in case an R <<
29 USB devices it is now exposed <<
30 of "direct". In device assignm <<
31 those RMRR are considered to b <<
32 <<
33 What: /sys/kernel/iommu_groups/<grp_ <<
34 Date: November 2020 <<
35 KernelVersion: v5.11 <<
36 Contact: Sai Praneeth Prakhya <sai.prane <<
37 Description: /sys/kernel/iommu_groups/<grp_ <<
38 domain in use by iommu for thi <<
39 for possible read values. A pr <<
40 change the group type by writi <<
41 <<
42 ======== ==================== <<
43 DMA All the DMA transact <<
44 are translated by th <<
45 DMA-FQ As above, but using <<
46 remove translations <<
47 overhead at the cost <<
48 identity All the DMA transact <<
49 are not translated b <<
50 but zero protection. <<
51 auto Change to the type t <<
52 ======== ==================== <<
53 <<
54 The default domain type of a g <<
55 <<
56 - The device in the group is n <<
57 So, the users must unbind th <<
58 changing the default domain <<
59 <<
60 Unbinding a device driver will <<
61 over the device and if done on <<
62 system could lead to catastrop <<
63 need to reboot the machine to <<
64 expected that the users unders <<
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