From: Jason Gunthorpe <jgg@ziepe•ca>
To: Mostafa Saleh <smostafa@google•com>
Cc: Ashish Mhetre <amhetre@nvidia•com>,
will@kernel•org, robin.murphy@arm•com, joro@8bytes•org,
nicolinc@nvidia•com, linux-arm-kernel@lists•infradead.org,
iommu@lists•linux.dev, linux-kernel@vger•kernel.org,
linux-tegra@vger•kernel.org
Subject: Re: [PATCH v3 0/3] iommu/arm-smmu-v3: Tegra264 invalidation workaround
Date: Tue, 2 Jun 2026 15:23:15 -0300 [thread overview]
Message-ID: <20260602182315.GH2487554@ziepe.ca> (raw)
In-Reply-To: <ah8FYa0hdkkAFQVp@google.com>
On Tue, Jun 02, 2026 at 04:31:29PM +0000, Mostafa Saleh wrote:
> On Mon, Jun 01, 2026 at 10:48:42AM +0000, Ashish Mhetre wrote:
> > Nvidia Tegra264 SMMUs are affected by an erratum where a TLB entry can
> > survive an invalidation that races with concurrent traffic targeting
> > the same entry. The hardware-recommended software workaround is to
> > issue every CFGI/TLBI command (each followed by CMD_SYNC) twice. The
> > second issue must execute only after the first issue's CMD_SYNC has
> > completed, giving the sequence:
>
> This seems quite intrusive, will the TLB entry survive if you push a
> full invalidation instead?
It's 36 lines and completely contained to the insides of the command
sumbissions code??
Stuff like this is why I was guiding you to use the more code exactly
as is for pkvm. Historically there have been many invalidation related
errata, and invalidate twice seems to be a theme in fixing many of
them.
Jason
prev parent reply other threads:[~2026-06-02 18:23 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-01 10:48 [PATCH v3 0/3] iommu/arm-smmu-v3: Tegra264 invalidation workaround Ashish Mhetre
2026-06-01 10:48 ` [PATCH v3 1/3] iommu/arm-smmu-v3: Factor out CMDQ batch force-sync conditions Ashish Mhetre
2026-06-02 19:55 ` Will Deacon
2026-06-02 20:08 ` Nicolin Chen
2026-06-02 20:23 ` Will Deacon
2026-06-01 10:48 ` [PATCH v3 2/3] iommu/arm-smmu-v3: Detect Tegra264 erratum Ashish Mhetre
2026-06-02 20:13 ` Will Deacon
2026-06-02 20:31 ` Nicolin Chen
2026-06-02 20:59 ` Will Deacon
2026-06-02 21:06 ` Nicolin Chen
2026-06-01 10:48 ` [PATCH v3 3/3] iommu/arm-smmu-v3: Issue CFGI/TLBI twice on Tegra264 Ashish Mhetre
2026-06-01 18:37 ` Nicolin Chen
2026-06-02 20:22 ` Will Deacon
2026-06-02 20:35 ` Nicolin Chen
2026-06-03 0:59 ` Jason Gunthorpe
2026-06-03 1:01 ` Jason Gunthorpe
2026-06-03 11:33 ` Will Deacon
2026-06-02 16:31 ` [PATCH v3 0/3] iommu/arm-smmu-v3: Tegra264 invalidation workaround Mostafa Saleh
2026-06-02 18:23 ` Jason Gunthorpe [this message]
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