IOMMU Updates for Linux v4.2
This time with bigger changes than usual:
* A new IOMMU driver for the ARM SMMUv3. This IOMMU is pretty
different from SMMUv1 and v2 in that it is configured through
in-memory structures and not through the MMIO register region.
The ARM SMMUv3 also supports IO demand paging for PCI devices
with PRI/PASID capabilities, but this is not implemented in
the driver yet.
* Lots of cleanups and device-tree support for the Exynos IOMMU
driver. This is part of the effort to bring Exynos DRM support
* Introduction of default domains into the IOMMU core code. The
rationale behind this is to move functionalily out of the
IOMMU drivers to common code to get to a unified behavior
between different drivers.
The patches here introduce a default domain for iommu-groups
(isolation groups). A device will now always be attached to a
domain, either the default domain or another domain handled by
the device driver. The IOMMU drivers have to be modified to
make use of that feature. So long the AMD IOMMU driver is
converted, with others to follow.
* Patches for the Intel VT-d drvier to fix DMAR faults that
happen when a kdump kernel boots. When the kdump kernel boots
it re-initializes the IOMMU hardware, which destroys all
mappings from the crashed kernel. As this happens before
the endpoint devices are re-initialized, any in-flight DMA
causes a DMAR fault. These faults cause PCI master aborts,
which some devices can't handle properly and go into an
undefined state, so that the device driver in the kdump kernel
fails to initialize them and the dump fails.
This is now fixed by copying over the mapping structures (only
context tables and interrupt remapping tables) from the old
kernel and keep the old mappings in place until the device
driver of the new kernel takes over. This emulates the the
behavior without an IOMMU to the best degree possible.
* A couple of other small fixes and cleanups.
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Merge branches 'arm/rockchip', 'arm/exynos', 'arm/smmu', 'x86/vt-d', 'x86/amd', 'default-domains' and 'core' into next