Windows Virtio Video driver mirror function

[huntercr42]

Is your feature request related to a problem? Please describe.

I have a single GPU passthrough working in Windows 10 in Gvt-D mode (Q35 UEFI) , but it will only work if the video card is the secondary display. The primary display is the virtio video device , but it will not mirror the display of my real GPU's monitor.
I have to use the vga/cirrus/bochs etc driver to get mirroring. This forces the screen to be limited to 1280x800 using Microsoft's default display driver.
Virtio gpu driver works great at any resolution but crucially does not allow for display mirroring.

Describe the solution you'd like

Implement whatever feature is missing form virtio gpu that is present in the "real" video drivers that makes windows see this interface as able to be paired up and mirrored.

Describe alternatives you've considered

Attempted to use other virtual drivers such as IDDSampledriver, Parsec Virtual Driver, etc but none of them implement this.

Additional context

• HOST: Intel NUC 6i7KyK Skull Canyon ( Skylake, Iris Pro 580 )
• QEMU emulator version 8.0.4 (Debian 1:8.0.4+dfsg-1ubuntu3.23.10.2)
• libvirtd (libvirt) 9.6.0
• Guest Windows 10 10.0.19045
• virtio drivers 0.1.240

I apologize that I am ignorant the underlying complexities here... I am hoping there is a way to get virtio to feed the right data to windows to satisfy it into allowing mirroring.