[sm_ts]

> 2. The passed-through card must have a monitor connected.

Regarding this, I don't know about LG, but with a standard QEMU VFIO setup, one use a single monitor connected to the two cards, and switch the input when required.

[gnif]

Yup, this is a good option too, makes it easy to debug/diagnose when things go wrong with the guest VM too.

Just note that not all multi-input monitors are equal though, a small minority appear to the GPU as unplugged when the input selection is changed.