Re: [BUG] VM stuck in interrupt-loop after suspend to/resumed from file, or no interrupts at all

["Daniel P. Berrange" <berrange@redhat.com>]

On Wed, Jan 12, 2011 at 03:51:13PM +0100, Philipp Hahn wrote:
> Hello,
> 
> libvirt implements a manages save, which suspens a VM to a file, from which it 
> can be resumed later. This uses Qemus/Kvms "migrate exec:<file>" feature.
> This doesn't work reliable for me: In may cases the resumed VM seems to be 
> stuck: its VNC console is restored, but no key presses or network packages 
> are accepted. This both happens with Windows XP, 7, 2008 and Linux 2.6.32 
> systems.
> 
> Using the debugging cycle described below in more detail I was able to track 
> the problem down to interrupt handling: Either the Linux-guest-kernel 
> constantly receives an interrupt for the 8139cp network adapter, or no 
> interrupts at all (neither network nor keyboard nor timer); only sending a 
> NMI works and shows that at least the Linux-Kernel is still alive.
> 
> If I add the -no-kvm-irqchip Option, it seems to work; I was not able to 
> reproduce a hang.

I remember reporting a bug with that scenario 4/5 months back
and it being fixed in the host kernel IIRC.

Daniel