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