Re: [PATCH v1 15/16] iommu/arm-smmu-v3: Add viommu cache invalidation support

From: Jason Gunthorpe
Date: Mon Aug 19 2024 - 14:28:35 EST


On Mon, Aug 19, 2024 at 11:19:39AM -0700, Nicolin Chen wrote:

> > But nesting enablment with out viommu is alot less useful than I had
> > thought :(
>
> Actually, without viommu, the hwpt cache invalidate alone could
> still support non-SVA case?

That is what I thought, but doesn't the guest still have to invalidate
the CD table entry # 0?

> Though we still have the blocker at the msi mapping... It still
> requires a solution, even for viommu series.

Yes, small steps. The point of this step was to get the nested paging
only (without msi, pri, etc, etc)

Jason