Commit 540c7abe authored by Wanpeng Li's avatar Wanpeng Li Committed by Paolo Bonzini
Browse files

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: default avatarLike Xu <likexu@tencent.com>
Signed-off-by: default avatarWanpeng Li <wanpengli@tencent.com>
Message-Id: <1634631160-67276-2-git-send-email-wanpengli@tencent.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 610265ea

arch/x86/include/asm/kvm_host.h

+0 −1
Original line number Diff line number Diff line
@@ -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;

arch/x86/kvm/vmx/pmu_intel.c

+2 −4
Original line number Diff line number Diff line
@@ -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);

}