PCIe PASID (Process Address Space ID) and iommu code

[Bjorn Helgaas]

[+cc Joerg, Suravee, Jay, iommu list, linux-pci]

Resending, as message got bounced for html content.
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Hi,
PCIe has introduced PASID TLP Prefix. There are two ECNs on this.
It seems that AMD iommu code makes use of PASID. Is there a device that
utilizes this TLP prefix?
PASID allocation and management within a device is not clear to me. How
does device know which PASID to issue for which virtual address? Who makes
the association? Must be software/OS, but how? There is no table for this
like MSI-X table.
Any pointer/documentation will be appreciated.
Regards,
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[Joerg Roedel]

Post by Bjorn Helgaas
[+cc Joerg, Suravee, Jay, iommu list, linux-pci]

Resending, as message got bounced for html content.
--------------------------------------------
Hi,
PCIe has introduced PASID TLP Prefix. There are two ECNs on this.
It seems that AMD iommu code makes use of PASID. Is there a device that
utilizes this TLP prefix?

Yes, recent radeon GPUs can make use of the TLP prefix.

Post by Bjorn Helgaas

PASID allocation and management within a device is not clear to me. How
does device know which PASID to issue for which virtual address? Who makes
the association? Must be software/OS, but how? There is no table for this
like MSI-X table.

The setup of the PASIDs is device specific, so there is no standard for
setting up PASID address spaces on devices.


HTH,

Joerg