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    SubjectRe: intel_pstate divide error with v3.13-rc4-256-gb7000ad
    On 01/03/2014 02:06 PM, Paolo Bonzini wrote:
    > Il 03/01/2014 21:00, Dirk Brandewie ha scritto:
    >> + case MSR_IA32_MPERF:
    >> + case MSR_IA32_APERF:
    >
    OK I will spin the patch to only add MSR_PLATFORM_INFO.

    > These should never be accessed. A KVM VM will always have
    > CPUID[06H].ECX = 0, and the Intel manual says that the MSRs are only
    > present if CPUID returns that value with bit 0 set.
    >
    > I think the actual bug is that intel_pstate_init does not check the
    > feature bits in CPUID (either manually or via x86_match_cpu).

    I will add the feature check.

    What are the differences between the first and the nested KVM's?
    At load time intel_pstate checks that APERF and MPERF are incrementing
    and that PLATFORM_INFO has some value. Somehow these checks pass
    in the nested environment and we fall over when the CPU is being added
    by cpufreq.

    --Dirk



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