[clug] QEMU with GPU passthrough, for a laptop?

[Tony Lewis]

Hi all,

I have a new laptop with a decent discrete Nvidia GPU, along with the 
integrated Intel one.  I'm keen to get the GPU to passthrough to a 
Windows VM for possibly some Windows gaming without leaving Linux.  The 
laptop has a HDMI port.

I'm stuck at the point where the guides tend to say, "now plug the 
external GPU into the monitor", because I don't know if the HDMI is 
fixed for one or other of the GPUs, or if it can be switched between.

Ideally I'd like the VM to be windowed (and then possibly maximised on a 
monitor), with GPU passthrough goodness, but I'm not sure if that can be 
done.  Is it possible?

Failing that, is it possible to dynamically tell / force which GPU is 
using the HDMI port?

I am a long way away from understanding this.  I'm trying not to just 
copy/paste from StackOverflow, but pennies are slow to drop. Kudos to 
the Arch wiki.  The information there is top notch and obviously 
well-curated.

Thanks,

Tony