Re: [PATCH v2 4/4] iommu/arm: Add BBM Level 2 smmu feature

[Jason Gunthorpe]

On Mon, Mar 03, 2025 at 07:03:42PM +0000, Mikołaj Lenczewski wrote:

> For example, if we use BBML2 for kernel mappings, does that require us
> to repaint all kernel mappings when disabling BBML2 on smmu attach? I
> am not sure, but definitely something to be worked out.

No, it would be a per-mm_struct basis only if we did something like
that

When the SMMU driver puts a SVA on top of the mm_struct it would
disable BBML2 usage only for that mm_struct and it's contained VMAs.

Kernel mappings are never made into a SVA so are not effected.
Userspace only.

Jason