From: Xiaoyao Li <xiaoyao.li@intel.com>
To: Li RongQing <lirongqing@baidu.com>,
linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
x86@kernel.org, hpa@zytor.com, bp@alien8.de, mingo@redhat.com,
tglx@linutronix.de, joro@8bytes.org, jmattson@google.com,
wanpengli@tencent.com, vkuznets@redhat.com,
sean.j.christopherson@intel.com, pbonzini@redhat.com
Subject: Re: [PATCH][v2] kvm: x86: emulate APERF/MPERF registers
Date: Thu, 30 Apr 2020 14:49:24 +0800 [thread overview]
Message-ID: <5aa01c91-b874-fd4f-a1fb-1d008753ca84@intel.com> (raw)
In-Reply-To: <1588139196-23802-1-git-send-email-lirongqing@baidu.com>
On 4/29/2020 1:46 PM, Li RongQing wrote:
> Guest kernel reports a fixed cpu frequency in /proc/cpuinfo,
> this is confused to user when turbo is enable, and aperf/mperf
> can be used to show current cpu frequency after 7d5905dc14a
> "(x86 / CPU: Always show current CPU frequency in /proc/cpuinfo)"
> so we should emulate aperf mperf to achieve it
>
> the period of aperf/mperf in guest mode are accumulated as
> emulated value, and add per-VM knod to enable emulate mperfaperf
>
> diff v1:
> 1. support AMD
> 2. support per-vm capability to enable
>
[...]
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index 851e9cc79930..1d157a8dba46 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -4310,6 +4310,12 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> case MSR_F10H_DECFG:
> msr_info->data = svm->msr_decfg;
> break;
> + case MSR_IA32_MPERF:
> + msr_info->data = vcpu->arch.v_mperf;
> + break;
> + case MSR_IA32_APERF:
> + msr_info->data = vcpu->arch.v_aperf;
> + break;
> default:
> return kvm_get_msr_common(vcpu, msr_info);
> }
> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
> index 91749f1254e8..b05e276e262b 100644
> --- a/arch/x86/kvm/vmx/vmx.c
> +++ b/arch/x86/kvm/vmx/vmx.c
> @@ -1914,6 +1914,12 @@ static int vmx_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
> !guest_cpuid_has(vcpu, X86_FEATURE_RDTSCP))
> return 1;
> goto find_shared_msr;
> + case MSR_IA32_MPERF:
> + msr_info->data = vcpu->arch.v_mperf;
> + break;
> + case MSR_IA32_APERF:
> + msr_info->data = vcpu->arch.v_aperf;
> + break;
They are same for both vmx and svm, you can put them in kvm_get_msr_common()
BTW, are those two MSR always readable regardless of guest's CPUID?
> default:
> find_shared_msr:
> msr = find_msr_entry(vmx, msr_info->index);
next prev parent reply other threads:[~2020-04-30 6:49 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-29 5:46 [PATCH][v2] kvm: x86: emulate APERF/MPERF registers Li RongQing
2020-04-29 8:54 ` Peter Zijlstra
2020-04-29 9:43 ` 答复: " Li,Rongqing
2020-04-29 10:21 ` Paolo Bonzini
2020-04-30 1:45 ` 答复: " Li,Rongqing
2020-04-30 6:49 ` Xiaoyao Li [this message]
2020-04-30 9:50 ` Li,Rongqing
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