Re: [PATCH v3 1/7] iommu/vt-d: Require DMA domain if hardware not support passthrough

Jason Gunthorpe
2024-08-06T16:54:27Z

On Tue, Aug 06, 2024 at 10:39:35AM +0800, Lu Baolu wrote:
> 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.
>
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> ---
> drivers/iommu/intel/iommu.c | 10 ++++++++++
> 1 file changed, 10 insertions(+)

Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>

Jason