Feature-Request: Add virgl support

[fabiohsouza]

I tryed change to

<video>
    <model type='virtio' heads='1'>
        <acceleration accel3d='yes'/>
    </model
</video>

but an error message saying the video model 'virtio' is not supported.

I am using for tests:
Ubuntu 15.10 - Kernel 4.4-rc7 (host/guest)
QEMU 2.5
Mesa 11.2
libvirt 1.2.21

https://www.redhat.com/archives/libvir-list/2015-November/msg01245.html

[savichev]

Latest in git - libvirtd version 1.3.1.
I compile for deb for test

Worked!
Debian 8 (host/guest)
Kernel: 4.4.0-040400rc7-generic (host/guest)
QEMU 2.5 (host)
mesa-dev_11.2.0 (host/guest)
libdrm-dev_2.4.66 (host/guest)
libvirt-namespaces._1.3.1 (host)

[savichev]

https://cgit.freedesktop.org/spice/spice/commit/?id=782c7508e28fdeee786cdcebffd22f772d7f09ec

GL acceleration (virgl)

OpenGL acceleration is currently local only (it has to go through a Unix socket)
and it needs guest support. It's currently limited to recent linux
distributions (for example up to date Fedora 23 + updated mesa packages from
https://copr.fedorainfracloud.org/coprs/kraxel/virgl/[copr:kraxel]).

Configuration

Using libvirt

You need to add a virtio-gpu video device to your virtual machine instead of QXL.
[source,xml]

<video>
   <model type='virtio' heads='1'>
     <acceleration accel3d='yes'/>
   </model>
 </video>

Then you need to enable OpenGL on your SPICE graphics node:
[source,xml]

<graphics type='spice' autoport='no'>
  <gl enable='yes'/>
</graphics>

You don't need any port/address as they won't be usable with GL.

Using QEMU

You need to add a virtio-gpu device on QEMU command line,
as well as enable GL with SPICE. port/tls-port/addr arguments
won't be used in this setup. You need to configure a Unix socket to
connect to the VM display.

[source,sh]
-device virtio-vga,virgl=on -spice gl=on,unix,addr=/run/user/1000/spice.sock

Connecting to the guest

Connecting to the guest when virgl is in use is slightly different
than usual

If libvirt is being used

[source,sh]
client$ virt-viewer -a $vmname

If a Unix socket has been set on QEMU command line

[source,sh]
client$ remote-viewer spice+unix:///run/user/1000/spice.sock

[zingmars]

While enabling virgl works, it breaks the NoVNC viewer as it fails to properly connect to the socket for some reason (blank screen followed by "Unexpected close while ready").