Black Screen with Spice and OpenGL acceleration in virt-manager with QEMU/KVM

[Cole Robinson]

On 5/1/20 7:28 AM, Filip Banák wrote:
> Hello.
> 
> I just want to use an Arch Linux guest with OpenGL 3D acceleration on
> with Spice.
> It works with Spice when the OpenGL acceleration is disabled.
> But when I enable it (with vitio graphics with accel3d yes of course), I
> only see a black screen, but when the VM boots I can interact with it
> through the keyboard blindly.
> Please see my forum thread here for more:
> https://forum.manjaro.org/t/qemu-kvm-vm-in-virt-manager-is-running-with-a-black-screen-when-opengl-acceleration-is-turned-on/138632
> 
> I also tested all this:
> 
> Working with no acceleration with Spice without gl=on in -display:
> qemu-system-x86_64 -drive file=/home/filip/VM/archlinux.qcow2 -m 8192
> -enable-kvm -M q35 -cpu host -smp 12,sockets=1,cores=12,threads=1
> -display spice-app -usb -device usb-tablet -bios
> /usr/share/ovmf/x64/OVMF_CODE.fd -boot order=c -device virtio-vga,virgl=on
> 
> 
> Not working with Spice with gl=on in -display, remote-viewer closes
> instantly:
> qemu-system-x86_64 -drive file=/home/filip/VM/archlinux.qcow2 -m 8192
> -enable-kvm -M q35 -cpu host -smp 12,sockets=1,cores=12,threads=1
> -display spice-app,gl=on -usb -device usb-tablet -bios
> /usr/share/ovmf/x64/OVMF_CODE.fd -boot order=c -device virtio-vga,virgl=on
> 
>     Error: qemu-system-x86_64: warning: Spice:
> dcc.c:664:dcc_push_monitors_config: monitors_config is NULL
>    
>    
> Probably Working with acceleration(just no graphical output) without
> Spice with -display gtk,gl=on
> qemu-system-x86_64 -drive file=/home/filip/VM/archlinux.qcow2 -m 8192
> -enable-kvm -M q35 -cpu host -smp 12,sockets=1,cores=12,threads=1
> -display gtk,gl=on -usb -device usb-tablet -bios
> /usr/share/ovmf/x64/OVMF_CODE.fd -boot order=c -device virtio-vga,virgl=on
> 
>     No error just black screen.
> 
>    
> Working with acceleration without Spice, just QEMU SDL:
> qemu-system-x86_64 -drive file=/home/filip/VM/archlinux.qcow2 -m 8192
> -enable-kvm -M q35 -cpu host -smp 12,sockets=1,cores=12,threads=1
> -display sdl,gl=on -usb -device usb-tablet -bios
> /usr/share/ovmf/x64/OVMF_CODE.fd -boot order=c -device virtio-vga,virgl=on
>  
>  
> Working with with Spice with acceleration with EGL-HEADLESS, gl=on in
> -display does not matter here, it is automatic/implied:
> qemu-system-x86_64 -name Arch -drive file=/home/filip/VM/archlinux.qcow2
> -m 8192 -enable-kvm -M q35 -cpu host -smp
> 12,sockets=1,cores=12,threads=1 -display egl-headless,gl=on -usb -device
> usb-tablet -bios /usr/share/ovmf/x64/OVMF_CODE.fd -boot order=c -device
> virtio-vga,virgl=on -spice
> disable-ticketing,image-compression=off,seamless-migration=on,unix,addr=/run/user/1000/spice.sock
> 
> remote-viewer --verbose --debug --spice-debug
> spice+unix:///run/user/1000/spice.sock
> 
> 
> Working SDL with acceleration, also can connect with Spice but see black
> screen but can use keyboard and mouse and see output on qemu sdl window:
> qemu-system-x86_64 -name Arch -drive file=/home/filip/VM/archlinux.qcow2
> -m 8192 -enable-kvm -M q35 -cpu host -smp
> 12,sockets=1,cores=12,threads=1 -usb -device usb-tablet -bios
> /usr/share/ovmf/x64/OVMF_CODE.fd -boot order=c -device
> virtio-vga,virgl=on -spice
> unix,addr=/run/user/1000/spice.sock,disable-ticketing,image-compression=off,seamless-migration=on
> -display sdl,gl=on
> 
> 
> Not working Remote Viewer opens but no output just "Connected to graphic
> server" in the middle of the window.
> qemu-system-x86_64 -name Arch -drive file=/home/filip/VM/archlinux.qcow2
> -m 8192 -enable-kvm -M q35 -cpu host -smp
> 12,sockets=1,cores=12,threads=1 -usb -device usb-tablet -bios
> /usr/share/ovmf/x64/OVMF_CODE.fd -boot order=c -device
> virtio-vga,virgl=on -spice
> gl=on,unix,addr=/run/user/1000/spice.sock,disable-ticketing,image-compression=off,seamless-migration=on
> 
> remote-viewer --verbose --debug --spice-debug
> spice+unix:///run/user/1000/spice.sock
> 
> I guess the problem when trying with virt-manager is the same as when
> trying with -display spice-app,gl=on.
> 
> Running on Manjaro linux with Nvidia GT630 graphics and Qemu version 4.2.
> Any help is appreciated.
> Thank you.

I may not have followed all the details, but have you gotten it working
with any setup via libvirt, or only with qemu on the command line? It
could be libvirt is not granting access to all the needed host resources
correctly, like the drm node path. Check
/var/log/libvirt/qemu/$vmname.log and see if qemu prints and errors

- Cole