[RFC PATCH v4 03/16] iommu/arm-smmu-v3: Add initial pSMMU realm viommu plumbing

[Nicolin Chen]

On Tue, Sep 01, 2026 at 12:12:22PM -0700, Nicolin Chen wrote:
> On Tue, Sep 01, 2026 at 02:42:30PM -0300, Jason Gunthorpe wrote:
> > On Tue, Sep 01, 2026 at 10:13:04AM -0700, Nicolin Chen wrote:
> > Is there anything more than RMI_VSMMU_CREATE needed from a RMM
> > perspective? What about that dpt/ats stuff?
> 
> DPT is a bit hacky currently..
> 
> Prior to RMM v2.0 ABI, DPT was allocated statically in RMM; there
> was no RMI command for DPT allocations.
> 
> Now, with RMM v2.0 ABI, DPT can be managed via RMIs. I am making
> it follow GPT at this point, similar to the static idea. But, in
> the long run, I will think of decoupling, but I haven't looked at
> that closely.

Did a quick check. It's clear.

DPT is a system-wise global thing, not per SMMU or per realm. Each
table or entry is indexed by part of 48-bit in PA corresponding to
to a protected IPA. One thing that is related to a realm is a VMID
in the leaf entry. So, it should unlikely be coupling with VSMMU.

The other stuff is to map VSMMU's MMIO region in its IPA space but
it should be a part of the VSMMU-CREATE package.

Nicolin