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Subject: Re: [PATCH 1/2] KVM: vmx/pmu: Fix dummy check if lbr_desc->event is
 created
To:     Like Xu <like.xu@linux.intel.com>,
        Sean Christopherson <seanjc@google.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,
        x86@kernel.org, linux-kernel@vger.kernel.org
References: <20210223013958.1280444-1-like.xu@linux.intel.com>
From:   Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <34fa477b-f630-43ee-1df5-f64bd57d90f1@redhat.com>
Date:   Tue, 23 Feb 2021 18:06:26 +0100
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On 23/02/21 02:39, Like Xu wrote:
> If lbr_desc->event is successfully created, the intel_pmu_create_
> guest_lbr_event() will return 0, otherwise it will return -ENOENT,
> and then jump to LBR msrs dummy handling.
> 
> Fixes: 1b5ac3226a1a ("KVM: vmx/pmu: Pass-through LBR msrs when the guest LBR event is ACTIVE")
> Signed-off-by: Like Xu <like.xu@linux.intel.com>
> ---
>   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 d1df618cb7de..d6a5fe19ff09 100644
> --- a/arch/x86/kvm/vmx/pmu_intel.c
> +++ b/arch/x86/kvm/vmx/pmu_intel.c
> @@ -320,7 +320,7 @@ static bool intel_pmu_handle_lbr_msrs_access(struct kvm_vcpu *vcpu,
>   	if (!intel_pmu_is_valid_lbr_msr(vcpu, index))
>   		return false;
>   
> -	if (!lbr_desc->event && !intel_pmu_create_guest_lbr_event(vcpu))
> +	if (!lbr_desc->event && intel_pmu_create_guest_lbr_event(vcpu))
>   		goto dummy;

Queued, adding a "< 0" to clarify the semantics of the function.

Paolo