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SubjectRe: PCIe PASID (Process Address Space ID) and iommu code
On Wed, Oct 15, 2014 at 09:50:58PM -0600, Bjorn Helgaas wrote:
> [+cc Joerg, Suravee, Jay, iommu list, linux-pci]
>
> On Wed, Oct 15, 2014 at 5:44 PM, Kallol Biswas <nucleodyne@gmail.com> wrote:
> > 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.

> > 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



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