From: Jason Gunthorpe <jgg@nvidia.com>
To: Robin Murphy <robin.murphy@arm.com>
Cc: will@kernel.org, catalin.marinas@arm.com, joro@8bytes.org,
jpb@kernel.org, iommu@lists.linux.dev,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 2/2] iommu/arm-smmu-v3: Add HAFT support for SVA
Date: Sat, 25 Jul 2026 11:27:59 -0300 [thread overview]
Message-ID: <amTH7xHBY2ol4LHw@nvidia.com> (raw)
In-Reply-To: <57ae366ec501a142bd20f2cc7d18b3eca8eeac25.1784814923.git.robin.murphy@arm.com>
On Thu, Jul 23, 2026 at 03:19:44PM +0100, Robin Murphy wrote:
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
> @@ -102,6 +102,8 @@ void arm_smmu_make_sva_cd(struct arm_smmu_cd *target,
> target->data[0] |= cpu_to_le64(CTXDESC_CD_0_TCR_HA);
> if (master->smmu->features & ARM_SMMU_FEAT_HD)
> target->data[0] |= cpu_to_le64(CTXDESC_CD_0_TCR_HD);
> + if (master->smmu->features & ARM_SMMU_FEAT_HAFT && system_supports_haft())
> + target->data[1] |= cpu_to_le64(CTXDESC_CD_1_HAFT);
> } else {
> target->data[0] |= cpu_to_le64(CTXDESC_CD_0_TCR_EPD0);
Based on the Sashiko remark and your note you should lift all the
HA/HD/HAFT bits outside this if (mm) block.
AFAICT it is fine for HA/HD/HAFT to be set with EPD0, the HW won't
process any PTEs so they won't have any effect.
Since this avoids the BAD_CD inconsistency you pointed at and also avoids
changing word 1 it should avoid the problematic V=0 transition.
Jason
next prev parent reply other threads:[~2026-07-25 14:28 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-23 14:19 [PATCH v2 0/2] iommu/arm-smmu-v3: Fix SVA vs. HAFT issues Robin Murphy
2026-07-23 14:19 ` [PATCH v2 1/2] arm64: Add override for MMFR1.HAFDBS Robin Murphy
2026-07-23 14:19 ` [PATCH v2 2/2] iommu/arm-smmu-v3: Add HAFT support for SVA Robin Murphy
2026-07-25 14:27 ` Jason Gunthorpe [this message]
2026-07-26 12:00 ` Will Deacon
2026-07-26 16:08 ` Jason Gunthorpe
2026-07-26 16:10 ` Jason Gunthorpe
2026-07-27 8:12 ` Will Deacon
2026-07-27 10:27 ` Robin Murphy
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