Messages in this thread Patch in this message |  | | Date | Mon, 27 Jan 2020 13:22:56 -0800 | Subject | [PATCH] KVM: x86: Fix perfctr WRMSR for running counters | From | Eric Hankland <> |
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Correct the logic in intel_pmu_set_msr() for fixed and general purpose counters. This was recently changed to set pmc->counter without taking in to account the value of pmc_read_counter() which will be incorrect if the counter is currently running and non-zero; this changes back to the old logic which accounted for the value of currently running counters.
Signed-off-by: Eric Hankland <ehankland@google.com> --- arch/x86/kvm/vmx/pmu_intel.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index 34a3a17bb6d7..9bdbe05b599c 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -264,9 +264,10 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) pmc->counter = data; else pmc->counter = (s32)data; + pmc->counter += pmc->counter - pmc_read_counter(pmc); return 0; } else if ((pmc = get_fixed_pmc(pmu, msr))) { - pmc->counter = data; + pmc->counter += data - pmc_read_counter(pmc); return 0; } else if ((pmc = get_gp_pmc(pmu, msr, MSR_P6_EVNTSEL0))) { if (data == pmc->eventsel)
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