From: Will Deacon <will@kernel.org>
To: catalin.marinas@arm.com, Robin Murphy <robin.murphy@arm.com>
Cc: kernel-team@android.com, Will Deacon <will@kernel.org>,
joro@8bytes.org, jean-philippe@linaro.org, iommu@lists.linux.dev,
linux-arm-kernel@lists.infradead.org, mark.rutland@arm.com,
joey.gouly@arm.com, ryan.roberts@arm.com, broonie@kernel.org
Subject: Re: [PATCH 1/2] iommu/arm-smmu-v3: Document SVA interaction with new pagetable features
Date: Tue, 10 Dec 2024 00:17:30 +0000 [thread overview]
Message-ID: <173378456062.4186718.3662609391353650164.b4-ty@kernel.org> (raw)
In-Reply-To: <68a37b00a720f0827cac0e4f40e4d3a688924054.1733406275.git.robin.murphy@arm.com>
On Thu, 05 Dec 2024 13:48:09 +0000, Robin Murphy wrote:
> Process pagetables may now be using new permission-indirection-based
> features which an SMMU may not understand when given such a table for
> SVA. Although SMMUv3.4 does add its own S1PIE feature, realistically
> we're still going to have to cope with feature mismatches between CPUs
> and SMMUs, so let's start simple and essentially just document the
> expectations for what falls out as-is. Although it seems unlikely for
> SVA applications to also depend on memory-hardening features, or
> vice-versa, the relative lifecycles make it tricky to enforce mutual
> exclusivity. Thankfully our PIE index allocation makes it relatively
> benign for an SMMU to keep interpreting them as direct permissions, the
> only real implication is that an SVA application cannot harden itself
> against its own devices with these features. Thus, inform the user about
> that just in case they have other expectations.
>
> [...]
Applied SMMU change to will (for-joerg/arm-smmu/updates), thanks!
[1/2] iommu/arm-smmu-v3: Document SVA interaction with new pagetable features
https://git.kernel.org/will/c/6e192214c6c8
Cheers,
--
Will
https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev
prev parent reply other threads:[~2024-12-10 0:22 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-05 13:48 [PATCH 1/2] iommu/arm-smmu-v3: Document SVA interaction with new pagetable features Robin Murphy
2024-12-05 13:48 ` [PATCH 2/2] arm64: cpufeature: Add GCS to cpucap_is_possible() Robin Murphy
2024-12-05 14:23 ` Mark Rutland
2024-12-05 15:04 ` Mark Brown
2024-12-05 15:25 ` Catalin Marinas
2024-12-05 15:55 ` Robin Murphy
2024-12-05 15:40 ` Mark Rutland
2024-12-05 15:52 ` Mark Brown
2024-12-05 18:14 ` [PATCH 1/2] iommu/arm-smmu-v3: Document SVA interaction with new pagetable features Jean-Philippe Brucker
2024-12-06 12:03 ` Robin Murphy
2024-12-05 18:23 ` (subset) " Catalin Marinas
2024-12-10 0:17 ` Will Deacon [this message]
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