Received-SPF: pass (google.com: domain of linux-kernel+bounces-35939-linux.lists.archive=gmail.com@vger.kernel.org designates 2604:1380:4601:e00::3 as permitted sender) client-ip=2604:1380:4601:e00::3;
Date: Tue, 23 Jan 2024 18:54:50 +0000
From: Oliver Upton <oliver.upton@linux.dev>
To: Yi Wang <up2wing@gmail.com>
Cc: seanjc@google.com, pbonzini@redhat.com, tglx@linutronix.de,
	mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com,
	x86@kernel.org, hpa@zytor.com, kvm@vger.kernel.org,
	linux-kernel@vger.kernel.org, wanpengli@tencent.com,
	foxywang@tencent.com, maz@kernel.org, anup@brainfault.org,
	atishp@atishpatra.org, borntraeger@linux.ibm.com,
	frankja@linux.ibm.com, imbrenda@linux.ibm.com
Subject: Re: [v2 4/4] KVM: s390: don't setup dummy routing when
 KVM_CREATE_IRQCHIP
Message-ID: <ZbALemDF9sAYS2AM@linux.dev>
References: <20240121111730.262429-1-foxywang@tencent.com>
 <20240121111730.262429-5-foxywang@tencent.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20240121111730.262429-5-foxywang@tencent.com>

On Sun, Jan 21, 2024 at 07:17:30PM +0800, Yi Wang wrote:
> As we have setup empty irq routing in kvm_create_vm(), there's
> no need to setup dummy routing when KVM_CREATE_IRQCHIP.
> 
> Signed-off-by: Yi Wang <foxywang@tencent.com>
> ---
>  arch/s390/kvm/kvm-s390.c | 13 +++++--------
>  1 file changed, 5 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index acc81ca6492e..7c836c973b75 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -2999,14 +2999,11 @@ int kvm_arch_vm_ioctl(struct file *filp, unsigned int ioctl, unsigned long arg)
>  		break;
>  	}
>  	case KVM_CREATE_IRQCHIP: {
> -		struct kvm_irq_routing_entry routing;
> -
> -		r = -EINVAL;
> -		if (kvm->arch.use_irqchip) {
> -			/* Set up dummy routing. */
> -			memset(&routing, 0, sizeof(routing));
> -			r = kvm_set_irq_routing(kvm, &routing, 0, 0);
> -		}
> +		/*
> +		 * As we have set up empty routing, there is no need to
> +		 * setup dummy routing here.
> +		 */

Where exactly?

In the context of this patch series it is rather obvious, but this
comment does not stand on its own. You can either throw the reader a
bone by mentioning where the dummy routing is created or just drop the
comment altogether.

> +		r = 0;
>  		break;
>  	}
>  	case KVM_SET_DEVICE_ATTR: {
> -- 
> 2.39.3
> 

-- 
Thanks,
Oliver