Re: [PATCH v3 2/2] iommu/arm-smmu-v3: Add HAFT support for SVA

Jason Gunthorpe <[email protected]> Tue, 28 Jul 2026 20:14:02 -0300
Newsgroups dev.linux.lists.iommu,org.infradead.lists.linux-arm-kernel
Message-ID <[email protected]>
On Mon, Jul 27, 2026 at 01:03:29PM +0100, Robin Murphy wrote:
> Since table access flags cannot be software-managed, if process
> pagetables are using HAFT then SVA must require the SMMU to support and
> enable it too, otherwise page aging is liable to get out of whack.
> 
> For unbinding, we can't disable HAFT atomically with HA as might be
> desired, but luckily we can get away with just not disabling HA either.
> 
> Cc: <[email protected]>
> Fixes: 62df5870ebf7 ("arm64: Enable ARCH_HAS_NONLEAF_PMD_YOUNG")
> Signed-off-by: Robin Murphy <[email protected]>
> ---
> 
> v3: Make all HTTU settings unconditional WRT mm.

Reviewed-by: Jason Gunthorpe <[email protected]>

Jason