@suse_rasputin you need to have an adapter available for pass through, not the Primary one…
Graphics:
Device-1: NVIDIA GP104GL [Tesla P4] driver: nvidia v: 550.54.14 <= OFFLOAD
Device-2: NVIDIA TU117GLM [Quadro T400 Mobile] driver: nvidia v: 550.54.14 <= PRIMARY DISPLAY
Device-3: NVIDIA GK208B [GeForce GT 710] driver: vfio-pci v: N/A <= PASSTHROUGH
I use libvirt here, so not sure for Virtualbox, guess it’s the same?