forked from luck/tmp_suning_uos_patched
perf/x86: Correctly use FEATURE_PDCM
The current code simply assumes Intel Arch PerfMon v2+ to have the IA32_PERF_CAPABILITIES MSR; the SDM specifies that we should check CPUID[1].ECX[15] (aka, FEATURE_PDCM) instead. This was found by KVM which implements v2+ but didn't provide the capabilities MSR. Change the code to DTRT; KVM will also implement the MSR and return 0. Cc: pbonzini@redhat.com Reported-by: "Michael S. Tsirkin" <mst@redhat.com> Suggested-by: Eduardo Habkost <ehabkost@redhat.com> Signed-off-by: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20140203132903.GI8874@twins.programming.kicks-ass.net Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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@ -2308,10 +2308,7 @@ __init int intel_pmu_init(void)
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if (version > 1)
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x86_pmu.num_counters_fixed = max((int)edx.split.num_counters_fixed, 3);
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/*
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* v2 and above have a perf capabilities MSR
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*/
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if (version > 1) {
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if (boot_cpu_has(X86_FEATURE_PDCM)) {
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u64 capabilities;
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rdmsrl(MSR_IA32_PERF_CAPABILITIES, capabilities);
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