Messages in this thread | | | Date | Wed, 19 Jun 2013 15:29:31 +0200 | From | Paolo Bonzini <> | Subject | Re: [PATCHv1] kvm guest: fix uninitialized kvmclock read by KVM guest |
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Il 19/06/2013 15:20, Batalov Eugene ha scritto: > > I've missed this detail. It looks like Igor's patch doesn't bring > secondary cpus kvm_clocksource behavior back to one before the regression, > Before the regression per_cpu variables are used to allocate > kvm_pv_clock areas. > To to usage of percpu variables bootstrap cpu kvm_clock area contents > were copied to smp secondary cpus kvm_clock areas when they were started. > Bootstrap cpu kvm_clock area was not zeroed at this time. > So kvm_pv_clock for secondary cpus never returned "zero" clock before > the regression. > > During the analysis of the bug I introduced idea to return zero before > kvm clocksource is initialized for secondary cpus > just like bootstrap cpu does on kernel boot. You can read that in BZ.
Yes, this is why I prefer to invert the two function calls. But Igor's patch fixes the hang (trivially because version is even) and is more appropriate for -rc6.
Paolo
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