RE: [PATCH v4 1/7] iommu/vt-d: Require DMA domain if hardware not support passthrough

[Tian, Kevin]

> From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> Sent: Friday, August 9, 2024 1:54 PM
> 
> The iommu core defines the def_domain_type callback to query the iommu
> driver about hardware capability and quirks. The iommu driver should
> declare IOMMU_DOMAIN_DMA requirement for hardware lacking pass-
> through
> capability.
> 
> Earlier VT-d hardware implementations did not support pass-through
> translation mode. The iommu driver relied on a paging domain with all
> physical system memory addresses identically mapped to the same IOVA
> to simulate pass-through translation before the def_domain_type was
> introduced and it has been kept until now. It's time to adjust it now
> to make the Intel iommu driver follow the def_domain_type semantics.
> 
> Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>

Reviewed-by: Kevin Tian <kevin.tian@xxxxxxxxx>