linux-kernel - Re: [PATCH] KVM: x86: Take advantage of kvm_arch_dy_has_pending

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Date:   Thu, 22 Apr 2021 12:35:58 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     lihaiwei.kernel@...il.com, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org
Cc:     seanjc@...gle.com, vkuznets@...hat.com, wanpengli@...cent.com,
        jmattson@...gle.com, joro@...tes.org,
        Haiwei Li <lihaiwei@...cent.com>
Subject: Re: [PATCH] KVM: x86: Take advantage of
 kvm_arch_dy_has_pending_interrupt()

On 21/04/21 05:25, lihaiwei.kernel@...il.com wrote:
> From: Haiwei Li <lihaiwei@...cent.com>
> 
> `kvm_arch_dy_runnable` checks the pending_interrupt as the code in
> `kvm_arch_dy_has_pending_interrupt`. So take advantage of it.
> 
> Signed-off-by: Haiwei Li <lihaiwei@...cent.com>
> ---
>   arch/x86/kvm/x86.c | 21 +++++++++------------
>   1 file changed, 9 insertions(+), 12 deletions(-)
> 
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index d696a9f..08bd616 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -11125,28 +11125,25 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
>   	return kvm_vcpu_running(vcpu) || kvm_vcpu_has_events(vcpu);
>   }
>   
> -bool kvm_arch_dy_runnable(struct kvm_vcpu *vcpu)
> +bool kvm_arch_dy_has_pending_interrupt(struct kvm_vcpu *vcpu)
>   {
> -	if (READ_ONCE(vcpu->arch.pv.pv_unhalted))
> -		return true;
> -
> -	if (kvm_test_request(KVM_REQ_NMI, vcpu) ||
> -		kvm_test_request(KVM_REQ_SMI, vcpu) ||
> -		 kvm_test_request(KVM_REQ_EVENT, vcpu))
> -		return true;
> -
>   	if (vcpu->arch.apicv_active && static_call(kvm_x86_dy_apicv_has_pending_interrupt)(vcpu))
>   		return true;
>   
>   	return false;
>   }
>   
> -bool kvm_arch_dy_has_pending_interrupt(struct kvm_vcpu *vcpu)
> +bool kvm_arch_dy_runnable(struct kvm_vcpu *vcpu)
>   {
> -	if (vcpu->arch.apicv_active && static_call(kvm_x86_dy_apicv_has_pending_interrupt)(vcpu))
> +	if (READ_ONCE(vcpu->arch.pv.pv_unhalted))
>   		return true;
>   
> -	return false;
> +	if (kvm_test_request(KVM_REQ_NMI, vcpu) ||
> +		kvm_test_request(KVM_REQ_SMI, vcpu) ||
> +		 kvm_test_request(KVM_REQ_EVENT, vcpu))
> +		return true;
> +
> +	return kvm_arch_dy_has_pending_interrupt(vcpu);
>   }
>   
>   bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
> 

Looks good, but I'd like to take a look at the other patches for 
directed yield first.  Thanks!

Paolo