Re: [PATCH v6 04/25] iommu/arm-smmu-v3: Move TLB range invalidation into common code

Jason Gunthorpe
2026-05-06T09:53:12Z

On Tue, May 05, 2026 at 04:43:13PM +0000, Mostafa Saleh wrote:
> On Tue, May 05, 2026 at 01:17:09PM -0300, Jason Gunthorpe wrote:
> > On Mon, May 04, 2026 at 12:15:17PM +0000, Mostafa Saleh wrote:
> >
> > > I am not sure if it’s worth it, the hypervisor is much simpler, there
> > > is a single page table, it’s locked (also identity mapped), it’s
> > > updated on VM boot/teardown only, we don’t even use iotlb_gather at
> > > the moment, although possible but I wanted to keep this series as
> > > simple as I can then we can add more features later.
> > > So this patch is the least intrusive change, as whatever the main SMMUv3
> > > driver does, the range tlb invalidation logic is the same.
> > > But I am happy to experiment with that when posted.
> >
> > Okay, then maybe just always push a full invalidation?
>
> Like full address space invalidation? that will not be optimal and
> will affect every device on the system, why would we do that if we
> know the address?

Not every device, just wipe the VMID. If you say it is rare then keep
it simple. If you need to be narrow then use the proper infastructure
with a gather. No reason to make something boutique for pkvm here.

Jason