Re: [PATCH 0/4] paravirt clock patches

Marcelo Tosatti
2008-05-08T23:10:45Z

On Wed, May 07, 2008 at 08:45:12PM +0200, Gerd Hoffmann wrote:
> Ok folks, here is the band aid fix for testing from the odd bugs
> department. Goes on top of the four patches of this series. A real,
> clean solution is TBD. Tomorrow I hope (some urgent private problems
> are in the queue too ...).
>
> Problem is the per-cpu area for cpu 0 has two locations in memory, one
> before and one after pda initialization. kvmclock registers the first
> due to being initialized quite early, and the paravirt clock for cpu 0
> stops seeing updates once the pda setup is done. Which makes the TSC
> effectively the base for timekeeping (instead of using the TSC for
> millisecond delta adjustments only). Secondary CPUs work as intended.
>
> This obviously screws up timekeeping on SMP guests, especially on hosts
> with unstable TSC.
>
> happy testing,

Gerd,

SMP guests can boot and seem stable. Thanks!