From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753369AbdBCNxa (ORCPT ); Fri, 3 Feb 2017 08:53:30 -0500 Received: from mail-wm0-f45.google.com ([74.125.82.45]:37410 "EHLO mail-wm0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753280AbdBCNx3 (ORCPT ); Fri, 3 Feb 2017 08:53:29 -0500 Date: Fri, 3 Feb 2017 14:53:25 +0100 From: Christoffer Dall To: Shanker Donthineni Cc: Marc Zyngier , Christoffer Dall , linux-kernel , linux-arm-kernel , Eric Auger , Paolo Bonzini , Vikram Sethi , kvmarm@lists.cs.columbia.edu Subject: Re: [PATCH] KVM: arm/arm64: vgic: Stop injecting the MSI occurrence twice 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-Disposition: inline In-Reply-To: <1486089003-413-1-git-send-email-shankerd@codeaurora.org> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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