Users in this community have had a difficult time with GPU passthrough over the years.
I want to share a quick recipe for how I got mine working.
Motherboard chipset: Intel z790 CPU: Intel Raptor Lake series GPU: NVIDIA RTX 4090 (24GB VRAM) QubesOS version: 4.1.2 (R4.1)
I followed the guide by @neowutran .
However, like others, I couldn’t run the GPU VM with more than a few GB of memory.
The trick was to set the max-ram-below-4g variable to 2G instead of 3.5G.
I now have a VM with a 4090 GPU and 32GB of RAM. nvidia-smi works and free -m shows all my memory.
Guest info:
I used an Arch install ISO image for debugging. The startup menu has an option for PCI device detection. (I tried the Debian installer ISO PCI device detection, but it didn’t work).
Arch is useful because it is easy to install the OS in BIOS mode, which QubesOS needs (guests can’t use UEFI). I want to try making an HVM TemplateVM next, that integrates with QubesOS better