Hello.

Sorry for possibly irrelevant bug report, but I just tested virgl and found it
broken - glxinfo works, but glxgears or any gl program segfaults.

On both host and guest (self-assembled live DVD) I have mesa Mesa 17.4.0-devel
(git-96fc5fbf23), X server 1.19.5. Host kernel - Linux slax 4.14.3-x64 #18 SMP
Sun Dec 3 09:13:07 MSK 2017 x86_64 AMD FX(tm)-4300 Quad-Core Processor
AuthenticAMD GNU/Linux, guest kernel - 4.12.0-x64.

Qemu - 2.11. Launch command and output:

qemu-system-x86_64 -M q35 -enable-kvm -cdrom /dev/shm/slax_16_12_2017_test.iso
-m 512 -display sdl,gl=on -soundhw es1370 -smp 4 -vga virtio -usbdevice mouse
qemu-system-x86_64: -usbdevice mouse: '-usbdevice' is deprecated, please use
'-device usb-...' instead
gl_version 33 - core profile enabled

startx inside guest works, glxinfo shows virgl as renderer, but glxgears or any
gl program (chromium BSU [old arcade game], glblur from xscreensavers)
segfaults.

At some point it was working better, but it was long ago .... (16.02.2016, to
be prescie).

I also run into assertion on qemu side, described here: 
https://lists.gnu.org/archive/html/qemu-devel/2017-04/msg05461.html

Because I had only dvd image connected as dvd rom - nothing bad happened, but
be aware about this abort if you connect real hard disk ....