From 83462301034ed148e03dbe98d80f2f2d209d4ba3 Mon Sep 17 00:00:00 2001
From: Eric Hankland <ehankland@google.com>
Date: Tue, 27 Sep 2022 14:56:48 +0800
Subject: [PATCH] KVM: x86: Fix perfctr WRMSR for running counters
mainline inclusion
from mainline-v5.5
commit 4400cf546b4bb62d49198f6642add01bf6e9b34d
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I5SDUS
CVE: NA
-------------
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>
Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
Reviewed-by: Zenghui Yu <yuzenghui@huawei.com>
Signed-off-by: Laibin Qiu <qiulaibin@huawei.com>
---
arch/x86/kvm/pmu_intel.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/arch/x86/kvm/pmu_intel.c b/arch/x86/kvm/pmu_intel.c
index c3f103e2b08e..2bdc8a5775ee 100644
--- a/arch/x86/kvm/pmu_intel.c
+++ b/arch/x86/kvm/pmu_intel.c
@@ -241,13 +241,12 @@ 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)
--
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