Re: [PATCH 06/13] PCI: Account for ACS egress control in isolation checks

[sashiko-bot@kernel.org]

> From: Leon Romanovsky <leonro@nvidia.com>
> 
> pci_acs_enabled() treats P2P Request Redirect as effective whenever its
> control bit is set. PCIe r7.0, sec 6.12.3, table 6-11 lets an enabled
> Egress Control Vector override it: a clear vector bit routes the request
> directly.
> 
> IOMMU grouping uses this check to prove peer requests cannot bypass the
> IOMMU, but cannot know every applicable vector bit, so Request Redirect
> gives no such guarantee while Egress Control is enabled.
> 
> Report Request Redirect as ineffective there, merging the devices into
> one IOMMU group, and report no isolation when the register cannot be
> read. Apply the same rule to the Intel SPT PCH quirk.
> 
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260802-fix-p2p-acs-v1-0-a7c5eb64fff6@nvidia.com?part=6