kvm guest hangs [was Re: Xen Dom0 [was Re: Announcing Fedora 11 Alpha (blink)]]
markmc at redhat.com
Fri Feb 6 10:22:59 UTC 2009
(Please respect my Reply-to:)
On Fri, 2009-02-06 at 19:10 +0900, John Summerfield wrote:
> Mark McLoughlin wrote:
> > 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.
> My debian guest uses tsc for its clock source (I just looked under sys,
> having read that bug report and got a clue). It has none of the pv stuff.
Ah, I missed that.
> I've also had problems installing CentOS 5.x guests, I don't think I've
> managed it yet.
> I didn't report it because I don't like "it doesn't work" reports, and
> really I had no more than that.
Well, we'd definitely prefer to have the report and work with you to get
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