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Re: [Xen-devel] [BUG 2.6.32.y] Broken PV migration between hosts with different uptime, non-monotonic time?

On 04/05/12 14:10, Philipp Hahn wrote:
> Hello David,
> On Friday 04 May 2012 12:39:03 David Vrabel wrote:
>> On 04/05/12 09:54, Philipp Hahn wrote:
>>> I encountered the following bug when migrating a Linux- PV
>>> domain on Xen-3.4.3 between different hosts, whose uptime differs by
>>> several minutes
> ... 
>> Xen 3.4 doesn't ensure that the TSC is stable across migrates (Xen 4.0
>> does).  If the host CPU has the CONSTANT_TSC bit in the Advanced Power
>> Management CPUID leaf it will pass this through to the guest which makes
>> the guest think the TSC is stable.
>> Can you try this libxc patch?
>> 8<------------------------
>> libxc: clear CONSTANT_TSC bit in Advanced Power Management CPUID leaf
> Excellent, that fixes the problem for me and makes perfect sense for me, 
> since 
> AFAIK 2.6.37 also received a big TSC patch which is not part of 2.6.32.y 
> backport.

Thanks for testing! I could never repro the migration failures.


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