Re: [PATCH v4 08/18] PCI: Account for Direct Translated P2P in ACS isolation checks

[Jason Gunthorpe]

> 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.

No, this whole patch misunderstand what "isolate" means in the context
of iommu groups.

Translated requests are *always* isolated becuase the translated
address always comes from the isolating iommu. We trust them just
fine.

-- 
Jason