From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752729AbdBCIZy (ORCPT ); Fri, 3 Feb 2017 03:25:54 -0500 Received: from mx1.redhat.com ([209.132.183.28]:52710 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752625AbdBCIZw (ORCPT ); Fri, 3 Feb 2017 03:25:52 -0500 Subject: Re: [PATCH] KVM: arm/arm64: vgic: Stop injecting the MSI occurrence twice To: Shanker Donthineni , Marc Zyngier , Christoffer Dall References: <1486089003-413-1-git-send-email-shankerd@codeaurora.org> Cc: Vikram Sethi , linux-kernel , linux-arm-kernel , Paolo Bonzini From: Auger Eric Message-ID: <9e5ed0dc-d32a-1ad5-f1ea-e46d51ec808a@redhat.com> Date: Fri, 3 Feb 2017 09:25:48 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: <1486089003-413-1-git-send-email-shankerd@codeaurora.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Fri, 03 Feb 2017 08:25:53 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Shanker, On 03/02/2017 03:30, 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 Reviewed-by: Eric Auger Thanks for catching that bug! Eric > --- > 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); > } > >