Re: [Qemu-devel] qemu-kvm guest which won't 'cont' (emulation failure?)

[Kevin Wolf]

Am 24.10.2011 12:00, schrieb Chris Webb:
> I have a qemu-kvm guest (apparently a Ubuntu 11.04 x86-64 install) which has
> stopped and refuses to continue:
> 
>   (qemu) info status
>   VM status: paused
>   (qemu) cont
>   (qemu) info status
>   VM status: paused
> 
> The host is running linux 2.6.39.2 with qemu-kvm 0.14.1 on 24-core Opteron
> 6176 box, and has nine other 2GB production guests on it running absolutely
> fine.
> 
> It's been a while since I've seen one of these. When I last saw a cluster of
> them, they were emulation failures (big real mode instructions, maybe?). I
> also remember a message about abnormal exit in the dmesg previously, but I
> don't have that here. This time, there is no host kernel output at all, just
> the paused guest.
> 
> I have qemu monitor access and can even strace the relevant qemu process if
> necessary: is it possible to use this to diagnose what's caused this guest
> to stop, e.g. the unsupported instruction if it's an emulation failure?

Another common cause for stopped VMs are I/O errors, for example writes
to a sparse image when the disk is full.

Kevin