1What: /sys/kernel/iommu_groups/ 2Date: May 2012 3KernelVersion: v3.5 4Contact: Alex Williamson <alex.williamson@redhat.com> 5Description: /sys/kernel/iommu_groups/ contains a number of sub- 6 directories, each representing an IOMMU group. The 7 name of the sub-directory matches the iommu_group_id() 8 for the group, which is an integer value. Within each 9 subdirectory is another directory named "devices" with 10 links to the sysfs devices contained in this group. 11 The group directory also optionally contains a "name" 12 file if the IOMMU driver has chosen to register a more 13 common name for the group. 14Users: 15 16What: /sys/kernel/iommu_groups/reserved_regions 17Date: January 2017 18KernelVersion: v4.11 19Contact: Eric Auger <eric.auger@redhat.com> 20Description: /sys/kernel/iommu_groups/reserved_regions list IOVA 21 regions that are reserved. Not necessarily all 22 reserved regions are listed. This is typically used to 23 output direct-mapped, MSI, non mappable regions. Each 24 region is described on a single line: the 1st field is 25 the base IOVA, the second is the end IOVA and the third 26 field describes the type of the region. 27 28What: /sys/kernel/iommu_groups/reserved_regions 29Date: June 2019 30KernelVersion: v5.3 31Contact: Eric Auger <eric.auger@redhat.com> 32Description: In case an RMRR is used only by graphics or USB devices 33 it is now exposed as "direct-relaxable" instead of "direct". 34 In device assignment use case, for instance, those RMRR 35 are considered to be relaxable and safe. 36