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

[Will Deacon]

On Wed, Jul 01, 2026 at 06:45:17PM +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.
> 
> Cc: <stable at vger.kernel.org>
> Fixes: 62df5870ebf7 ("arm64: Enable ARCH_HAS_NONLEAF_PMD_YOUNG")
> Signed-off-by: Robin Murphy <robin.murphy at arm.com>
> ---
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 5 +++++
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c     | 6 ++++++
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h     | 3 +++
>  3 files changed, 14 insertions(+)

This looks ok to *me*, but Sashiko raises two interesting points:

https://sashiko.dev/#/patchset/878cd6bcbbe2d5677d2f63da13294c148268552c.1782927917.git.robin.murphy@arm.com

1. This may break hitless updates when transitioning to a faulting entry.
2. IORT has HTTU overrides for HA/HD. Does it (will it?) have anything
   for HAFT? At the moment, it looks like you'll trigger a warning
   message.

Given Jason's comments, it's probably worth sending the idreg override
patch as well...

Will