Ubuntu
qemu-kvm package

  1. Bug #615077
  2. Comment #8

Comment 8 for bug 615077

Revision history for this message
Nigel Jones (dev-nigelj) wrote :

I've tagged the bug regression-potential as it looks like a regression between Lucid & Maverick, here is what I know from reproducing:

Reproduction:
Bug can be reproduced by creating (in virt-manager) on a clean Maverick install, by creating a virtual machine, editing the configuration (using virt-manager), remove the VNC device, and replace it with an SDL Local device. Upon starting the machine, it will not start and after a period will display an error to such effect.

If you access /var/log/libvirt/qemu/<vmname>.log and copy & paste the kvm command (along w/ environment variables, you will likely crash X completely.

I have also successfully reproduced this issue w/ upstream git HEAD & qemu-kvm_0.12.4+noroms-0ubuntu6_amd64.deb (earlier version that what Dave suggested the issue started with).

Observations:
When $XAUTHORITY is set correctly (when running the command manually - also likely if you 'virsh edit $vmname' and set the path there as well), an strace looks fairly normal, and similar to that of under Lucid, no framebuttle calls etc.

When $XAUTHORITY is not set correctly and is run from the terminal (gnome-terminal for instance) it looks like the KVM command attempts to open the framebuffer (/dev/fb) and perform a lot of ioctl calls on it (http://www.linuxjournal.com/article/2783 for a good explanation in laymans terms of what the ioctls are calling for), as a result Xorg pretty much dies, the screen goes blank (but backlight is still on), but there is no ability to switch VTs etcs, it is only possible to SSH into the machine. The KVM process also dies.

I found that generating an X configuration disabling AIGLX & booting w/ 'nomodeset' (and removing the quiet & splash in the process) allowed me to recover w/ Ctrl+Alt+F1, Ctrl+Alt+F7, and Ctrl+C the process (it is still running, unlike w/ modesetting/aiglx).

For reference, this machine is running a fairly bog standard fresh installation (now fully up to date) and has a ATI Mobility Radeon HD 4500 Series card, using the open source modules/etc, I've had no problems w/ KVM/etc on this laptop (under both Ubuntu & Fedora) in the past, both using the open source graphics.

I'll upload strace output in a moment...