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Subject: Re: [PATCH] KVM: x86: Check the right feature bit for
 MSR_KVM_ASYNC_PF_ACK access
To:     Vitaly Kuznetsov <vkuznets@redhat.com>, kvm@vger.kernel.org
Cc:     Sean Christopherson <seanjc@google.com>,
        Wanpeng Li <wanpengli@tencent.com>,
        Jim Mattson <jmattson@google.com>,
        Oliver Upton <oupton@google.com>, linux-kernel@vger.kernel.org
References: <20210722123018.260035-1-vkuznets@redhat.com>
From:   Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <a8500354-b204-3e21-f6c9-1e6a80f88851@redhat.com>
Date:   Mon, 26 Jul 2021 14:27:01 +0200
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On 22/07/21 14:30, Vitaly Kuznetsov wrote:
> MSR_KVM_ASYNC_PF_ACK MSR is part of interrupt based asynchronous page fault
> interface and not the original (deprecated) KVM_FEATURE_ASYNC_PF. This is
> stated in Documentation/virt/kvm/msr.rst.
> 
> Fixes: 66570e966dd9 ("kvm: x86: only provide PV features if enabled in guest's CPUID")
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
>   arch/x86/kvm/x86.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index d715ae9f9108..88ff7a1af198 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -3406,7 +3406,7 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>   			return 1;
>   		break;
>   	case MSR_KVM_ASYNC_PF_ACK:
> -		if (!guest_pv_has(vcpu, KVM_FEATURE_ASYNC_PF))
> +		if (!guest_pv_has(vcpu, KVM_FEATURE_ASYNC_PF_INT))
>   			return 1;
>   		if (data & 0x1) {
>   			vcpu->arch.apf.pageready_pending = false;
> @@ -3745,7 +3745,7 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
>   		msr_info->data = vcpu->arch.apf.msr_int_val;
>   		break;
>   	case MSR_KVM_ASYNC_PF_ACK:
> -		if (!guest_pv_has(vcpu, KVM_FEATURE_ASYNC_PF))
> +		if (!guest_pv_has(vcpu, KVM_FEATURE_ASYNC_PF_INT))
>   			return 1;
>   
>   		msr_info->data = 0;
> 

Queued, thanks.

Paolo