I want to convert my current system (ubuntu 20.10) that already has an AMD GPU for the host and a KVM Windows with passed-thru NVIDIA.
System is based on Gigabyte Aorus Master X570.
I would like to add a third GPU and set the system up with Proxmox (using AMD GPU). A second (Ubuntu 20.10) VM should then have the added GPU passed-thru and be able to use it.
Since I would need to by a new, beefier powersupply for that, I’d like to get a feeling first if this was possible at all. (I am aware that the GPUs in slot one and two would be required to share the x16 lanes as 2 x8). But, would there be any further pitfalls?
Will the second slot (sharing the x16 lanes as 2x8) have it’s own IOMMU group?
Or will it be the same as the first GPU?
And if so, is it possible to isolate it for the ubuntu VM?
Oh, and the two guests should be able to run simultaneously.