From: Jason Gunthorpe <jgg@nvidia.com>
To: Nicolin Chen <nicolinc@nvidia.com>
Cc: will@kernel.org, robin.murphy@arm.com, joro@8bytes.org,
linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev,
linux-kernel@vger.kernel.org, skolothumtho@nvidia.com,
praan@google.com
Subject: Re: [PATCH rc v1 3/4] iommu/arm-smmu-v3: Ignore STE EATS when computing the update sequence
Date: Sat, 6 Dec 2025 15:46:37 -0400 [thread overview]
Message-ID: <20251206194637.GH1219718@nvidia.com> (raw)
In-Reply-To: <db1450e7a5989e51756a7ec3285d70ee90bae24f.1764982046.git.nicolinc@nvidia.com>
On Fri, Dec 05, 2025 at 04:52:02PM -0800, Nicolin Chen wrote:
> From: Jason Gunthorpe <jgg@nvidia.com>
>
> If a VM want to toggle EATS off the hypervisor will see EATS change to 0
> and insert a V=0 breaking update into the STE even though the VM did not
> ask for that.
"EATS off at the same time as changing CFG"
In bare metal EATS is ignored by CFG=ABORT/BYPASS which is why this
doesn't cause a problem until we have nested where CFG is always a
variation of S2 trans that does use EATS.
Jason
next prev parent reply other threads:[~2025-12-06 19:46 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-06 0:51 [PATCH rc v1 0/4] iommu/arm-smmu-v3: Fix hitless STE update in nesting cases Nicolin Chen
2025-12-06 0:52 ` [PATCH rc v1 1/4] iommu/arm-smmu-v3: Add ignored bits to fix STE update sequence Nicolin Chen
2025-12-06 14:19 ` Shuai Xue
2025-12-06 19:38 ` Jason Gunthorpe
2025-12-06 19:34 ` Jason Gunthorpe
2025-12-06 19:45 ` Nicolin Chen
2025-12-06 19:57 ` Jason Gunthorpe
2025-12-07 4:37 ` Nicolin Chen
2025-12-07 16:09 ` Jason Gunthorpe
2025-12-07 19:35 ` Nicolin Chen
2025-12-07 20:11 ` Nicolin Chen
2025-12-06 0:52 ` [PATCH rc v1 2/4] iommu/arm-smmu-v3: Ignore STE MEV when computing the " Nicolin Chen
2025-12-06 0:52 ` [PATCH rc v1 3/4] iommu/arm-smmu-v3: Ignore STE EATS " Nicolin Chen
2025-12-06 19:46 ` Jason Gunthorpe [this message]
2025-12-06 19:54 ` Nicolin Chen
2025-12-06 0:52 ` [PATCH rc v1 4/4] iommu/arm-smmu-v3-test: Add nested s1bypass coverage Nicolin Chen
2025-12-06 12:34 ` Shuai Xue
2025-12-06 19:42 ` Jason Gunthorpe
2025-12-06 19:50 ` Nicolin Chen
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