From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoffer Dall Subject: Re: [PATCH] KVM: arm/arm64: vgic: Stop injecting the MSI occurrence twice Date: Fri, 3 Feb 2017 14:53:25 +0100 Message-ID: <20170203135325.GL27852@cbox> References: <1486089003-413-1-git-send-email-shankerd@codeaurora.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from localhost (localhost [127.0.0.1]) by mm01.cs.columbia.edu (Postfix) with ESMTP id F013140838 for ; Fri, 3 Feb 2017 08:53:04 -0500 (EST) Received: from mm01.cs.columbia.edu ([127.0.0.1]) by localhost (mm01.cs.columbia.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 46n53-qT9QSb for ; Fri, 3 Feb 2017 08:53:03 -0500 (EST) Received: from mail-wm0-f47.google.com (mail-wm0-f47.google.com [74.125.82.47]) by mm01.cs.columbia.edu (Postfix) with ESMTPS id D692740284 for ; Fri, 3 Feb 2017 08:53:03 -0500 (EST) Received: by mail-wm0-f47.google.com with SMTP id c85so30020244wmi.1 for ; Fri, 03 Feb 2017 05:53:28 -0800 (PST) Content-Disposition: inline In-Reply-To: <1486089003-413-1-git-send-email-shankerd@codeaurora.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kvmarm-bounces@lists.cs.columbia.edu Sender: kvmarm-bounces@lists.cs.columbia.edu To: Shanker Donthineni Cc: Marc Zyngier , linux-kernel , linux-arm-kernel , Paolo Bonzini , kvmarm@lists.cs.columbia.edu List-Id: kvmarm@lists.cs.columbia.edu Hi Shanker, [please cc the kvmarm list for kvm/arm patches, thanks] On Thu, Feb 02, 2017 at 08:30:03PM -0600, Shanker Donthineni wrote: > The IRQFD framework calls the architecture dependent function > twice if the corresponding GSI type is edge triggered. For ARM, > the function kvm_set_msi() is getting called twice whenever the > IRQFD receives the event signal. The rest of the code path is > trying to inject the MSI without any validation checks. No need > to call the function vgic_its_inject_msi() second time to avoid > an unnecessary overhead in IRQ queue logic. It also avoids the > possibility of VM seeing the MSI twice. > > Simple fix, return -1 if the argument 'level' value is zero. > > Signed-off-by: Shanker Donthineni > --- > virt/kvm/arm/vgic/vgic-irqfd.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/virt/kvm/arm/vgic/vgic-irqfd.c b/virt/kvm/arm/vgic/vgic-irqfd.c > index d918dcf..f138ed2 100644 > --- a/virt/kvm/arm/vgic/vgic-irqfd.c > +++ b/virt/kvm/arm/vgic/vgic-irqfd.c > @@ -99,6 +99,9 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e, > if (!vgic_has_its(kvm)) > return -ENODEV; > > + if (!level) > + return -1; > + > return vgic_its_inject_msi(kvm, &msi); > } > > -- Reviewed-by: Christoffer Dall