iommu/amd: Add HATDis feature support

Current AMD IOMMU assumes Host Address Translation (HAT) is always
supported, and Linux kernel enables this capability by default. However,
in case of emulated and virtualized IOMMU, this might not be the case.
For example,current QEMU-emulated AMD vIOMMU does not support host
translation for VFIO pass-through device, but the interrupt remapping
support is required for x2APIC (i.e. kvm-msi-ext-dest-id is also not
supported by the guest OS). This would require the guest kernel to boot
with guest kernel option iommu=pt to by-pass the initialization of
host (v1) table.

The AMD I/O Virtualization Technology (IOMMU) Specification Rev 3.10 [1]
introduces a new flag 'HATDis' in the IVHD 11h IOMMU attributes to indicate
that HAT is not supported on a particular IOMMU instance.

Therefore, modifies the AMD IOMMU driver to detect the new HATDis
attributes, and disable host translation and switch to use guest
translation if it is available. Otherwise, the driver will disable DMA
translation.

[1] https://www.amd.com/content/dam/amd/en/documents/processor-tech-docs/specifications/48882_IOMMU.pdf

Reviewed-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Ankit Soni <Ankit.Soni@amd.com>
Link: https://lore.kernel.org/r/8109b208f87b80e400c2abd24a2e44fcbc0763a5.1749016436.git.Ankit.Soni@amd.com
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

0 files changed, 0 insertions, 0 deletions