Re: [PATCH] iommu/arm-smmu-v3: Add HAFT support for SVA
Will Deacon <[email protected]>
| Newsgroups | dev.linux.lists.iommu,org.infradead.lists.linux-arm-kernel,org.kernel.vger.stable |
|---|---|
| Message-ID | <amDEmlcyC3Tfmkel@willie-the-truck> |
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: <[email protected]> > Fixes: 62df5870ebf7 ("arm64: Enable ARCH_HAS_NONLEAF_PMD_YOUNG") > Signed-off-by: Robin Murphy <[email protected]> > --- > 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