From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60151) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dsaig-0002LK-Q3 for qemu-devel@nongnu.org; Thu, 14 Sep 2017 16:26:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dsaid-0007f5-DB for qemu-devel@nongnu.org; Thu, 14 Sep 2017 16:26:42 -0400 Received: from mx1.redhat.com ([209.132.183.28]:43200) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1dsaid-0007eJ-7L for qemu-devel@nongnu.org; Thu, 14 Sep 2017 16:26:39 -0400 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5114E4A6F4 for ; Thu, 14 Sep 2017 20:26:38 +0000 (UTC) References: <1505420247-23685-1-git-send-email-mgamal@redhat.com> From: Thomas Huth Message-ID: <4e386f8e-a4f5-7646-a37c-353d6f8068c8@redhat.com> Date: Thu, 14 Sep 2017 22:26:31 +0200 MIME-Version: 1.0 In-Reply-To: <1505420247-23685-1-git-send-email-mgamal@redhat.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] intel_iommu: Return error on machines with no PCI List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Mohammed Gamal , qemu-devel@nongnu.org Cc: pbonzini@redhat.com, ehabkost@redhat.com, mst@redhat.com On 14.09.2017 22:17, Mohammed Gamal wrote: > Starting the following command line causes a segfault > qemu-system-x86_64 -S -machine isapc,accel=kvm -device intel-iommu > > This is due to the fact that the machine type 'isapc' doesn't have > a PCI bus, while intel_iommu doesn't check if the machine has PCI support > and subsequently does a null-pointer access. Intel IOMMU shouldn't even work > if the target machine doesn't have PCI. > > Add a check for PCI on the given machine type and return an error if PCI > is not supported. > > Signed-off-by: Mohammed Gamal > --- > hw/i386/intel_iommu.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/hw/i386/intel_iommu.c b/hw/i386/intel_iommu.c > index 3a5bb0b..fab0b4b 100644 > --- a/hw/i386/intel_iommu.c > +++ b/hw/i386/intel_iommu.c > @@ -3041,6 +3041,13 @@ static void vtd_realize(DeviceState *dev, Error **errp) > } > > bus = pcms->bus; > + > + if (!bus) { > + error_setg(errp, "Machine-type '%s' does not support PCI", > + mc->name); > + return; > + } > + > x86_iommu->type = TYPE_INTEL; > > if (!vtd_decide_config(s, errp)) { > Patch looks basically fine to me, too, but I think I'd also rather change the "if (!pcms)" at the beginning of the function into "if (!pcms || !pcms->bus)" here to use the same error message for both cases. Thomas