Messages in this thread | | | Date | Mon, 06 Jan 2014 09:18:44 -0800 | From | Dirk Brandewie <> | Subject | Re: intel_pstate divide error with v3.13-rc4-256-gb7000ad |
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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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