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