tree 71f336edfc63d0dfeae330d03bccd45f40f5b0bd
parent fe82dcec644244676d55a1384c958d5f67979adb
author Will Deacon <will.deacon@arm.com> 1412006706 -0600
committer Alex Williamson <alex.williamson@redhat.com> 1412006706 -0600

iommu: introduce domain attribute for nesting IOMMUs

Some IOMMUs, such as the ARM SMMU, support two stages of translation.
The idea behind such a scheme is to allow a guest operating system to
use the IOMMU for DMA mappings in the first stage of translation, with
the hypervisor then installing mappings in the second stage to provide
isolation of the DMA to the physical range assigned to that virtual
machine.

In order to allow IOMMU domains to be used for second-stage translation,
this patch adds a new iommu_attr (IOMMU_ATTR_NESTING) for setting
second-stage domains prior to device attach. The attribute can also be
queried to see if a domain is actually making use of nesting.

Acked-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>