VirGL 3D Acceleration on KVM with LibVirt and Nvidia Drivers

Nvidia drivers seem to be causing issues with the normal 3D acceleration libvirt configuration in virt-manager and Gnome Boxes. What happens is that the viewer returns a black/blank screen when the normal configuration to enable VirGL is applied -

<graphics type="spice">

  <listen type="none"/>

  <gl rendernode="/dev/dri/renderD128"/>

</graphics>

<video>

  <model type="virtio" heads="1" primary="yes">

    <acceleration accel3d="yes"/>

  </model>

  <address type="pci" domain="0x0000" bus="0x00" slot="0x01" function="0x0"/>

</video>

The error that it returns is -

qemu_spice_gl_scanout_texture: failed to get fd for texture

Looking around, this seems to be a problem due to EGL support being required for with the proprietary Nvidia drivers. The configuration that worked for me was this -

<graphics type="spice">

  <listen type="none"/>

</graphics>

<graphics type="egl-headless">

  <gl rendernode="/dev/dri/renderD128"/>

</graphics>

<video>

  <model type="virtio" heads="1" primary="yes">

    <acceleration accel3d="yes"/>

  </model>

  <address type="pci" domain="0x0000" bus="0x00" slot="0x01" function="0x0"/>

</video>

To check it is working inside the VM, use the following commands on the terminal in the VM -

$ dmesg |grep -i drm

[    5.326446] systemd[1]: Starting Load Kernel Module drm...

[    5.869884] [drm] pci: virtio-vga detected at 0000:00:01.0

[    5.871953] [drm] features: +virgl +edid

[    5.873360] [drm] number of scanouts: 1

[    5.873365] [drm] number of cap sets: 2

[    5.882054] [drm] cap set 0: id 1, max-version 1, max-size 308

[    5.882247] [drm] cap set 1: id 2, max-version 2, max-size 688

[    5.885640] [drm] Initialized virtio_gpu 0.1.0 0 for virtio0 on minor 0

[    5.891133] virtio_gpu virtio0: fb0: virtio_gpudrmfb frame buffer device

$ glxinfo |grep -i vir

    Device: virgl (0x1010)

OpenGL renderer string: virgl