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Message-ID: <0a33c287-3394-c3df-9bee-ef13fe3417e4@nvidia.com>
Date:   Tue, 26 Apr 2022 08:30:25 +0100
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Subject: Re: [Patch v2] iommu: arm-smmu: disable large page mappings for
 Nvidia arm-smmu
Content-Language: en-US
To:     Will Deacon <will@kernel.org>,
        linux-arm-kernel@lists.infradead.org, linux-tegra@vger.kernel.org,
        iommu@lists.linux-foundation.org, thierry.reding@gmail.com,
        vdumpa@nvidia.com, Ashish Mhetre <amhetre@nvidia.com>,
        joro@8bytes.org, robin.murphy@arm.com, linux-kernel@vger.kernel.org
Cc:     catalin.marinas@arm.com, kernel-team@android.com,
        nicolinc@nvidia.com, Snikam@nvidia.com,
        Pritesh Raithatha <praithatha@nvidia.com>
References: <20220421081504.24678-1-amhetre@nvidia.com>
 <165053012237.502660.4418683392126519698.b4-ty@kernel.org>
From:   Jon Hunter <jonathanh@nvidia.com>
In-Reply-To: <165053012237.502660.4418683392126519698.b4-ty@kernel.org>
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Hi Will,

On 22/04/2022 11:55, Will Deacon wrote:
> On Thu, 21 Apr 2022 13:45:04 +0530, Ashish Mhetre wrote:
>> Tegra194 and Tegra234 SoCs have the erratum that causes walk cache
>> entries to not be invalidated correctly. The problem is that the walk
>> cache index generated for IOVA is not same across translation and
>> invalidation requests. This is leading to page faults when PMD entry is
>> released during unmap and populated with new PTE table during subsequent
>> map request. Disabling large page mappings avoids the release of PMD
>> entry and avoid translations seeing stale PMD entry in walk cache.
>> Fix this by limiting the page mappings to PAGE_SIZE for Tegra194 and
>> Tegra234 devices. This is recommended fix from Tegra hardware design
>> team.
>>
>> [...]
> 
> Applied to will (for-joerg/arm-smmu/fixes), thanks!
> 
> [1/1] iommu: arm-smmu: disable large page mappings for Nvidia arm-smmu
>        https://git.kernel.org/will/c/4a25f2ea0e03
> 

Thanks for applying. Sorry to be late to the party, but feel free
to add my ...

Reviewed-by: Jon Hunter <jonathanh@nvidia.com>

Also any chance we could tag for stable? Probably the most
appropriate fixes-tag would be ...

Fixes: aab5a1c88276 ("iommu/arm-smmu: add NVIDIA implementation for ARM MMU-500 usage")

Thanks!
Jon

-- 
nvpublic