Re: KVM: x86: workaround SuSE's 2.6.16 pvclock vs masterclock issue

Radim Krčmář
2015-01-21T14:09:31Z

2015-01-20 15:54-0200, Marcelo Tosatti:
> SuSE's 2.6.16 kernel fails to boot if the delta between tsc_timestamp
> and rdtsc is larger than a given threshold:
[...]
> Disable masterclock support (which increases said delta) in case the
> boot vcpu does not use MSR_KVM_SYSTEM_TIME_NEW.

Why do we care about 2.6.16 bugs in upstream KVM?

The code to benefit tradeoff of this patch seems bad to me ...
MSR_KVM_SYSTEM_TIME is deprecated -- we could remove it now, with
MSR_KVM_WALL_CLOCK (after hiding KVM_FEATURE_CLOCKSOURCE) if we want
to support old guests.