Splitting Intel iGPU between LXC and VM with HDMI output

[blinkercityprof]

Hello, I am hoping for some help tracking down assistance getting a proxmox node setup to accomplish the following:

• Plex Hardware transcoding in an LXC
• Intel iGPU accessible in an Ubuntu VM
• HDMI output from the Ubuntu VM

The setup is an Intel NUC12WSKi7 (i7-1260P) running VE 8.0.9 on kernel 6.2.16-19-pve
I've followed a few guides (https://www.derekseaman.com/2023/06...u-vt-d-passthrough-with-intel-alder-lake.html was the most informative) in an attempt to get this working, but I'm still stuck. I have IOMMU functional, with multiple VGA devices listed with an lspci on the proxmox node.

#  lspci
00:00.0 Host bridge: Intel Corporation Device 4621 (rev 02)
00:02.0 VGA compatible controller: Intel Corporation Alder Lake-P Integrated Graphics Controller (rev 0c)
00:02.1 VGA compatible controller: Intel Corporation Alder Lake-P Integrated Graphics Controller (rev 0c)
00:02.2 VGA compatible controller: Intel Corporation Alder Lake-P Integrated Graphics Controller (rev 0c)
00:02.3 VGA compatible controller: Intel Corporation Alder Lake-P Integrated Graphics Controller (rev 0c)
00:02.4 VGA compatible controller: Intel Corporation Alder Lake-P Integrated Graphics Controller (rev 0c)
00:02.5 VGA compatible controller: Intel Corporation Alder Lake-P Integrated Graphics Controller (rev 0c)
00:02.6 VGA compatible controller: Intel Corporation Alder Lake-P Integrated Graphics Controller (rev 0c)
00:02.7 VGA compatible controller: Intel Corporation Alder Lake-P Integrated Graphics Controller (rev 0c)

Within the Plex LXC I am able to select from a list of 7 "Intel Corporation Alder Lake-P Integrated Graphics Controller"

On the Ubuntu VM I have installed the Intel drivers from here: https://github.com/intel/compute-runtime/releases
But I am unable to get the VM to output to one of the HDMI ports

Does anyone have steps that I could follow to get HDMI output functional?