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Subject: Re: [PATCH 2/2] KVM: not link irqfd with a fake IRQ bypass producer
To:     Zhenzhong Duan <zhenzhong.duan@gmail.com>,
        linux-kernel@vger.kernel.org,
        virtualization@lists.linux-foundation.org, kvm@vger.kernel.org
Cc:     netdev@vger.kernel.org, pbonzini@redhat.com,
        sean.j.christopherson@intel.com, vkuznets@redhat.com,
        wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org,
        tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, mst@redhat.com
References: <20201019090657.131-1-zhenzhong.duan@gmail.com>
 <20201019090657.131-2-zhenzhong.duan@gmail.com>
From:   Jason Wang <jasowang@redhat.com>
Message-ID: <7eec99d5-e36b-ee5b-5b6c-1486e453a083@redhat.com>
Date:   Tue, 20 Oct 2020 14:32:12 +0800
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On 2020/10/19 下午5:06, Zhenzhong Duan wrote:
> In case failure to setup Post interrupt for an IRQ, it make no sense
> to assign irqfd->producer to the producer.
>
> This change makes code more robust.


It's better to describe what issue we will get without this patch.

Thanks


>
> Signed-off-by: Zhenzhong Duan <zhenzhong.duan@gmail.com>
> ---
>   arch/x86/kvm/x86.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index ce856e0..277e961 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -10683,13 +10683,14 @@ int kvm_arch_irq_bypass_add_producer(struct irq_bypass_consumer *cons,
>   		container_of(cons, struct kvm_kernel_irqfd, consumer);
>   	int ret;
>   
> -	irqfd->producer = prod;
>   	kvm_arch_start_assignment(irqfd->kvm);
>   	ret = kvm_x86_ops.update_pi_irte(irqfd->kvm,
>   					 prod->irq, irqfd->gsi, 1);
>   
>   	if (ret)
>   		kvm_arch_end_assignment(irqfd->kvm);
> +	else
> +		irqfd->producer = prod;
>   
>   	return ret;
>   }