From: "Xu, Like" <like.xu@intel.com>
To: Sean Christopherson <sean.j.christopherson@intel.com>,
Paolo Bonzini <pbonzini@redhat.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Like Xu <like.xu@linux.intel.com>
Subject: Re: [PATCH] KVM: VMX: Always treat MSR_IA32_PERF_CAPABILITIES as a valid PMU MSR
Date: Thu, 4 Jun 2020 09:37:59 +0800 [thread overview]
Message-ID: <46f57aa8-e278-b4fd-7ac8-523836308051@intel.com> (raw)
In-Reply-To: <20200603203303.28545-1-sean.j.christopherson@intel.com>
On 2020/6/4 4:33, Sean Christopherson wrote:
> Unconditionally return true when querying the validity of
> MSR_IA32_PERF_CAPABILITIES so as to defer the validity check to
> intel_pmu_{get,set}_msr(), which can properly give the MSR a pass when
> the access is initiated from host userspace.
Regardless of the MSR is emulated or not, is it a really good assumption that
the guest cpuids are not properly ready when we do initialization from host
userspace
?
> The MSR is emulated so
> there is no underlying hardware dependency to worry about.
>
> Fixes: 27461da31089a ("KVM: x86/pmu: Support full width counting")
> Cc: Like Xu <like.xu@linux.intel.com>
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> ---
>
> KVM selftests are completely hosed for me, everything fails on KVM_GET_MSRS.
At least I tried "make --silent -C tools/testing/selftests/kvm run_tests"
and how do I reproduce the "everything fails" for this issue ?
Thanks,
Like Xu
>
> arch/x86/kvm/vmx/pmu_intel.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
> index d33d890b605f..bdcce65c7a1d 100644
> --- a/arch/x86/kvm/vmx/pmu_intel.c
> +++ b/arch/x86/kvm/vmx/pmu_intel.c
> @@ -181,7 +181,7 @@ static bool intel_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
> ret = pmu->version > 1;
> break;
> case MSR_IA32_PERF_CAPABILITIES:
> - ret = guest_cpuid_has(vcpu, X86_FEATURE_PDCM);
> + ret = 1;
> break;
> default:
> ret = get_gp_pmc(pmu, msr, MSR_IA32_PERFCTR0) ||
next prev parent reply other threads:[~2020-06-04 1:38 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-03 20:33 [PATCH] KVM: VMX: Always treat MSR_IA32_PERF_CAPABILITIES as a valid PMU MSR Sean Christopherson
2020-06-04 1:37 ` Xu, Like [this message]
2020-06-04 15:16 ` Sean Christopherson
2020-06-04 16:20 ` Paolo Bonzini
2020-06-04 16:44 ` Jim Mattson
2020-06-04 16:49 ` Paolo Bonzini
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