On Mon, Mar 07, 2022 at 11:06:46AM +0100, Juergen Gross wrote: > > diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c > > index 4420499f7bb4..a1f179ed39bf 100644 > > --- a/arch/x86/kernel/paravirt.c > > +++ b/arch/x86/kernel/paravirt.c > > @@ -145,6 +145,15 @@ DEFINE_STATIC_CALL(pv_sched_clock, native_sched_clock); > > void paravirt_set_sched_clock(u64 (*func)(void)) > > { > > + /* > > + * Anything with ART on promises to have sane TSC, otherwise the whole > > + * ART thing is useless. In order to make ART useful for guests, we > > + * should continue to use the TSC. As such, ignore any paravirt > > + * muckery. > > + */ > > + if (cpu_feature_enabled(X86_FEATURE_ART)) > > + return; > > + > > static_call_update(pv_sched_clock, func); > > } > > > > NAK, this will break live migration of a guest coming from a host > without this feature. I thought the whole live-migration nonsense made sure to equalize crud like that. That is, then don't expose ART to the guest.
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