| 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. |