Bug#599161: xen-linux-system-2.6.32-5-xen-amd64: Clock moved forward 50 minutes, caused Xen HVM domU restart
On Wed, Oct 06, 2010 at 12:05:18PM +0100, Mark Adams wrote:
> > > As this is when the clock went from 18:00 to 18:50 and started the chain
> > > of events (restarted the 2008 domU). Any ideas why this log occurred?
> >
> > The TSC appeared to go backwards by a fairly significant amount, which
> > has upset the kernel.
> >
> > The behaviour of the virtual TSC as seen by an HVM guest is controlled
> > by a combination of the tsc_mode setting in your domain configuration
> > and, I think, by the features of your specific hardware (some have
> > constant rate TSC, others advertise varying levels of synchronisation
> > between cores etc). It's then up to the guest kernel whether it even
> > uses TSC as a timesource at all and how it handles instability etc and
> > how it derives other time sources (such as the wallclock time) from it.
> >
> > Sorry this isn't more helpful, but as I say you will probably get better
> > answers on one of the Xen mailing lists.
>
> Hi Ian,
>
> Thanks for your notes. I've already tried the xen-users list so I will
> try xen-devel to see if I can glean any more information about my issue.
> I will update the report here when I get any more information.
Did you contact them? From what I read from the bug report so far, running
an NTP client in the HVM host should suffice.
Cheers,
Moritz
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