On Fri, Aug 07, 2020 at 10:54:51AM -0700, Dey, Megha wrote:

So from the hierarchical domain standpoint, we will have:
- For DSA device: vector->intel-IR->IDXD
- For Jason's device: root domain-> domain A-> Jason's device's IRQ domain
- For any other intel IMS device in the future which
    does not require interrupt remapping: vector->new device IRQ domain
    requires interrupt remapping: vector->intel-IR->new device IRQ domain

I think you need a better classification than Jason's device or
Intel's device :)

Shouldn't the two cases be either you take the parent domain from the
IOMMU or you take the parent domain from the pci device?

What other choices could a PCI driver make?

Jason