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authorEric Hankland <ehankland@google.com>2020-01-27 13:22:56 -0800
committerPaolo Bonzini <pbonzini@redhat.com>2020-02-05 16:01:15 +0100
commit4400cf546b4bb62d49198f6642add01bf6e9b34d (patch)
tree7dc14820cd501a5bd7f6c0b463545a8f591148e5 /arch
parenta83502314ce303c6341b249c41121759c7477ba1 (diff)
downloadlinux-4400cf546b4bb62d49198f6642add01bf6e9b34d.tar.bz2
KVM: x86: Fix perfctr WRMSR for running counters
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> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/vmx/pmu_intel.c9
1 files changed, 4 insertions, 5 deletions
diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index 34a3a17bb6d7..fd21cdb10b79 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -260,13 +260,12 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
break;
default:
if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0))) {
- if (msr_info->host_initiated)
- pmc->counter = data;
- else
- pmc->counter = (s32)data;
+ if (!msr_info->host_initiated)
+ data = (s64)(s32)data;
+ pmc->counter += data - 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)