Re: [PATCH 04/13] PCI: Account for Direct Translated P2P in ACS isolation checks

[Logan Gunthorpe]

On 2026-08-02 09:09, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@xxxxxxxxxx>
> 
> PCIe r7.0, sec 6.12.3:
> 
>   peer-to-peer Memory Requests whose Address Type (AT) field indicates a
>   Translated address must be routed to the peer Port/Function without
>   redirection, regardless of ACS P2P Request Redirect and ACS P2P Egress
>   Control settings.
> 
> Request Redirect therefore does not isolate devices below a Port with
> ACS Direct Translated P2P enabled.
> 
> Sec 6.12.1.1 makes such a Request an ACS Violation once Translation
> Blocking is enabled, and that error "must take precedence over ... ACS
> P2P control mechanisms". Report isolation only in that case. Without
> Translation Blocking, devices below such a Port now share an IOMMU
> group.
> 
> Fixes: ad805758c0eb ("PCI: add ACS validation utility")
> Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxx>

LGTM

Reviewed-by: Logan Gunthorpe <logang@xxxxxxxxxxxx>