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

Jason Gunthorpe <[email protected]>
Newsgroups org.kernel.vger.linux-doc,dev.linux.lists.iommu,org.kernel.vger.linux-kernel,org.kernel.vger.linux-pci
Message-ID <178761377055.3197084.15973808736458853831.b4-review@b4>
> 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
lmpx.com only provides a reader for public news (NNTP) servers. It is not affiliated with the servers or forums shown here and is not responsible for the content of articles, which is written by their respective authors.