From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [PATCH] VT-d: improve RMRR validity checking Date: Tue, 9 Mar 2010 16:30:26 -0500 Message-ID: <20100309213026.GA12602@phenom.dumpdata.com> References: <4B59098B.6000108@intel.com> <4B590FA4.4000008@jp.fujitsu.com> <4B59132B.40607@intel.com> <4B59188C.50901@jp.fujitsu.com> <4B59660F.4000909@intel.com> <7162ab21003091339i4adb8669safd5e074607386a2@mail.gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Return-path: Content-Disposition: inline In-Reply-To: <7162ab21003091339i4adb8669safd5e074607386a2@mail.gmail.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Alex Williamson Cc: "xen-devel@lists.xensource.com" , Noboru Iwamatsu , "Kay, Allen M" , "Cihula, Joseph" , Weidong Han , "linux@eikelenboom.it" , "keir.fraser@eu.citrix.com" List-Id: xen-devel@lists.xenproject.org On Tue, Mar 09, 2010 at 02:39:10PM -0700, Alex Williamson wrote: > On Fri, Jan 22, 2010 at 1:47 AM, Weidong Han wr= ote: > > I implemented a patch and attached. > > > > patch description: > > =A0 In order to make Xen more defensive to VT-d related BIOS issue, t= his patch > > ignores a DRHD if all devices under its scope are not pci discoverabl= e, and > > regards a DRHD as invalid and then disable whole VT-d if some devices= under > > its scope are not pci discoverable. But if iommu=3Dforce is set, it w= ill > > enable all DRHDs reported by BIOS, to avoid any security vulnerabilit= y with > > malicious s/s re-enabling "supposed disabled" devices. =A0Pls note th= at we > > don't know the devices under the "Include_all" DRHD are existent or n= ot, > > because the scope of "Include_all" DRHD =A0won't enumerate common pci= device, > > it only enumerates I/OxAPIC and HPET devices. >=20 > Hi All, >=20 > I have a system with what I consider to be a valid DRHD that's getting > tripped up on this patch. The problem is that the DRHD includes an > IOAPIC scope, where the IOAPIC is not materialized on the PCI bus. I > think Xen is being overzealous in it's validity checking and that this > is a valid configuration. What do others think? Are IOAPICs a How does upstream Linux handle this? > special case that we can allow to be non-existent on the PCI bus? > Thanks, >=20 > Alex >=20 > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xensource.com > http://lists.xensource.com/xen-devel