Re: [PATCH] iommu/amd: Add Secure ATS support

[Jason Gunthorpe <jgg@ziepe.ca>]

On Wed, Feb 26, 2025 at 09:09:29AM +0800, Yi Liu wrote:
> > What are the options here?
> >   1) Translated Address (TA) is a full physical address and IOMMU does
> >      do anything (today)

> do you mean "do nothing"?

Yes

> > Not sure how to setup #4? The core code also needs to detect coherent
> > systems (ie CXL/etc) and refuse to do anything other than #1/#4..
> 
> The DPT and the HPT validates physical addresses. So such tables need to be
> programmed when a physical address is mapped in I/O page table. So the
> choice may be associating it with paging domain (e.g. the S2 domain that
> converts GPA to PA). If so, a domain alloc flag is also a good start.

Hmm, so you imagine doing it as a side structure under the map
operation.. Maybe, that will complicate my effort to unify the page
tables somewhat, but maybe not too badly.

Jason