kvm guest hangs [was Re: Xen Dom0 [was Re: Announcing Fedora 11 Alpha (blink)]]

[Mark McLoughlin]

On Fri, 2009-02-06 at 18:55 +0900, John Summerfield wrote:
> Mark McLoughlin wrote:
> 
> > 
> > Try booting the guest with clocksource=acpi_pm on the kernel command
> > line. If that helps, it's this bug:
> > 
> >   https://bugzilla.redhat.com/475598
> > 
> > It's an issue with KVM's paravirt clock. We have a workaround in the
> > rawhide host kernel which disables kvmclock support on affected hosts. A
> > real fix is in progress upstream.
> > 
> > The F-10 branch has the workaround, but only for the 2.6.29 builds. I
> > don't think we have it in the 2.6.27 updates (i.e. the
> > private-fedora-10-2_6_27 branch).
> > 
> > Chuck, could we get linux-2.6-kvmclock-unsync-tsc-workaround.patch
> > pulled into F-10?
> 
> I'm fully virtualised. I think. What's this about a paravirt clock in KVM?

KVM uses hardware virtualization support to run guests, yes, but it also
allows guests to use paravirtualization for some performance critical
operations - so e.g. pv block/network drivers, pv clock and pv MMU.

Cheers,
Mark.