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SubjectRe: [PATCH 3/4] iommu/vt-d: Support PASID DMA for in-kernel usage
On Fri, Dec 10, 2021 at 09:50:25AM -0800, Jacob Pan wrote:

> > Tying pasid to an iommu_domain is not a good idea. An iommu_domain
> > represents an I/O address translation table. It could be attached to a
> > device or a PASID on the device.
>
> I don;t think we can avoid storing PASID at domain level or the group's
> default domain. IOTLB flush is per domain. Default domain of DMA type
> is already tying to PASID0, right?

No, it is just wrong.

If the HW requires a list of everything that is connected to the
iommu_domain then it's private iommu_domain should have that list.

But it is a *list* not a single PASID.

If one device has 10 PASID's pointing to this domain you must flush
them all if that is what the HW requires.

Jason

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