From c64b8caaf8eea7bd81e2ffb778c1b12e51c7832d Mon Sep 17 00:00:00 2001 From: Wanpeng Li Date: Tue, 19 Oct 2021 01:12:39 -0700 Subject: [PATCH] KVM: vPMU: Fill get_msr MSR_CORE_PERF_GLOBAL_OVF_CTRL w/ 0 SDM section 18.2.3 mentioned that: "IA32_PERF_GLOBAL_OVF_CTL MSR allows software to clear overflow indicator(s) of any general-purpose or fixed-function counters via a single WRMSR." It is R/W mentioned by SDM, we read this msr on bare-metal during perf testing, the value is always 0 for ICX/SKX boxes on hands. Let's fill get_msr MSR_CORE_PERF_GLOBAL_OVF_CTRL w/ 0 as hardware behavior and drop global_ovf_ctrl variable. Tested-by: Like Xu Signed-off-by: Wanpeng Li Message-Id: <1634631160-67276-2-git-send-email-wanpengli@tencent.com> Signed-off-by: Paolo Bonzini --- arch/x86/include/asm/kvm_host.h | 1 - arch/x86/kvm/vmx/pmu_intel.c | 6 ++---- 2 files changed, 2 insertions(+), 5 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index b4fece3bb0612..1c523b5c99d13 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -499,7 +499,6 @@ struct kvm_pmu { u64 fixed_ctr_ctrl; u64 global_ctrl; u64 global_status; - u64 global_ovf_ctrl; u64 counter_bitmask[2]; u64 global_ctrl_mask; u64 global_ovf_ctrl_mask; diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c index 10cc4f65c4efd..b8e0d21b7c8a0 100644 --- a/arch/x86/kvm/vmx/pmu_intel.c +++ b/arch/x86/kvm/vmx/pmu_intel.c @@ -365,7 +365,7 @@ static int intel_pmu_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) msr_info->data = pmu->global_ctrl; return 0; case MSR_CORE_PERF_GLOBAL_OVF_CTRL: - msr_info->data = pmu->global_ovf_ctrl; + msr_info->data = 0; return 0; default: if ((pmc = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0)) || @@ -423,7 +423,6 @@ static int intel_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) if (!(data & pmu->global_ovf_ctrl_mask)) { if (!msr_info->host_initiated) pmu->global_status &= ~data; - pmu->global_ovf_ctrl = data; return 0; } break; @@ -588,8 +587,7 @@ static void intel_pmu_reset(struct kvm_vcpu *vcpu) pmc->counter = 0; } - pmu->fixed_ctr_ctrl = pmu->global_ctrl = pmu->global_status = - pmu->global_ovf_ctrl = 0; + pmu->fixed_ctr_ctrl = pmu->global_ctrl = pmu->global_status = 0; intel_pmu_release_guest_lbr_event(vcpu); } -- 2.39.5