[RFC PATCH] iommu/arm-smmu-v3: Allow nested attach for PCI bridges without vDEVICE

[Dmitry Malkin]

Hi Jason,

> If viommu should support multi-device groups, I'm not sure. I want to
> know why you even have multi-device groups in the first place because
> that is not normal at all.

That is because of the 'pci=config_acs' kernel command-line parameter. This causes the kernel to create a single IOMMU group containing multiple PCIe devices, including the bridge (PCIe Root Port).

Dmitry