Messages in this thread | | | Subject | Re: perf with precise attribute kills all KVM based VMs | From | Peter Zijlstra <> | Date | Wed, 11 Jul 2012 11:49:47 +0200 |
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On Wed, 2012-07-11 at 10:10 +0300, Gleb Natapov wrote:
> Looks like Avi is right about the overshoot. Can you test something like this? > > diff --git a/arch/x86/kernel/cpu/perf_event_intel.c b/arch/x86/kernel/cpu/perf_event_intel.c > index 166546e..5fb371a 100644 > --- a/arch/x86/kernel/cpu/perf_event_intel.c > +++ b/arch/x86/kernel/cpu/perf_event_intel.c > @@ -1374,8 +1374,11 @@ static struct perf_guest_switch_msr *intel_guest_get_msrs(int *nr) > arr[0].msr = MSR_CORE_PERF_GLOBAL_CTRL; > arr[0].host = x86_pmu.intel_ctrl & ~cpuc->intel_ctrl_guest_mask; > arr[0].guest = x86_pmu.intel_ctrl & ~cpuc->intel_ctrl_host_mask; > + arr[1].msr = MSR_IA32_PEBS_ENABLE; > + arr[1].host = cpuc->pebs_enabled; > + arr[1].guest = 0; > + *nr = 2; > > - *nr = 1; > return arr; > }
You also need to clear TR, BTS, BTINT from MSR_IA32_DEBUGCTLMSR and ideally you'd also clear MSR_IA32_DS_AREA so that any write will be a proper NULL deref or such.
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