Messages in this thread | | | From | Andy Lutomirski <> | Date | Fri, 27 Jul 2018 15:58:13 -0700 | Subject | Re: [PATCH v14 8/9] KVM: x86: virtualize cpuid faulting |
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On Fri, Jul 27, 2018 at 2:30 PM, Jim Mattson <jmattson@google.com> wrote: > On Fri, Jul 27, 2018 at 2:05 PM, Andy Lutomirski <luto@kernel.org> wrote: >> Does KVM *have* a concept of "maximum non-turbo frequency" of the >> guest that it would make sense to expose here? If so, presumably the >> right solution is to expose it. > > KVM has the concept of a guest's invariant TSC frequency. The Maximum > Non-Turbo Ratio is just some fraction of that. Sadly, the fraction is > 100 MHz, 133.33MHz, or the "scalable bus frequency" from some other > MSR, depending on microarchitecture.
Which is problematic, unless KVM wants to start deciding what the base clock is. There's MSR_FSB_FREQ, which is supported on Atom only, IIRC.
I really wish Intel would get its act together.
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