How to fix "BAR0 is 0M" error and NVIDIA driver probe failure after GPU Passthrough?

[mildred]

Hi everyone, I'm having trouble passing through an NVIDIA GPU to a VM. The VM boots up fine, but I keep seeing driver errors in the Guest OS journal as follows:

kernel: nvidia 0000:01:00.0: enabling device (0000 -> 0002)
kernel: NVRM: This PCI I/O region assigned to your NVIDIA device is invalid:
NVRM: BAR0 is 0M @ 0x0 (PCI:0000:01:00.0)
kernel: nvidia: probe of 0000:01:00.0 failed with error -1
kernel: NVRM: The NVIDIA probe routine failed for 1 device(s).

I've double-checked my passthrough settings and they seem correct, but the driver just won't recognize the hardware address. Does anyone know what might be causing this?

 

[pulipulichen]

Seeing this error code usually points to PCI resource allocation issues. Could you clarify whether your VM is using OVMF (UEFI) or SeaBIOS?

Also, what's the VRAM capacity of this GPU?
If you are using a newer model with high VRAM, that is likely the culprit.