Messages in this thread | | | Subject | Re: [PATCH v6 5/5] x86/kvm: Avoid dynamic allocation of pvclock data when SEV is active | From | Paolo Bonzini <> | Date | Tue, 11 Sep 2018 12:19:13 +0200 |
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On 11/09/2018 12:01, Borislav Petkov wrote: > On Tue, Sep 11, 2018 at 11:26:21AM +0200, Paolo Bonzini wrote: >> Usually the kvmclock structs are all the same, but there is support for >> old machines with inconsistent TSCs (across different sockets typically). > > Would that be a problem, though? Sounds like an "improvement" to me. :-) > > I mean, if we keep using the same TSC across all vCPUs, the guest will > actually see a single TSC and thus have stable and synchronized TSCs. > Unlike the host.
That's exactly what kvmclock is for, it provides a stable and synchronized clock on top of unsynchronized TSCs. But that's also why you need one struct per vCPU, at least in the synchronized case.
Paolo
> I.e., the guest will be better than the host! :-) >
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