7950x3D iGPU IOMMU/passthrough. Working in Windows 10 guest - can it work in Linux client?

Describe the problem

To enable using the integrated GPU on the Ryzen 7950x3D in a guest VM

Describe the new feature behavior

As long as the GPU video/audio PCIe devices are in their own IOMMU group, it should be possible to pass them through to a guest Linux VM.

This currently already works with a Windows 10 guest. It does not currently work with a Linux guest.

Describe the target user/application

Enabling the use of graphics acceleration in a guest VM.

How do you plan to validate this feature

By trying this in Proxmox on a guest Linux VM

Business case

Like any virtualisation, improves utilisation of hardware

Draft of the userspace API

Not sure what to put here?