From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: [konrad.wilk@oracle.com: [PATCH 1 of 1] Intel VT-D: Don't turn x2APIC if there is a missing DRHD entry for the IOAPIC] Date: Wed, 10 Mar 2010 10:38:23 -0500 Message-ID: <20100310153823.GA5243@phenom.dumpdata.com> References: <4B9756CE020000780005A7A1@vpn.id2.novell.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: "Zhang, Xiantao" Cc: "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org On Wed, Mar 10, 2010 at 04:42:19PM +0800, Zhang, Xiantao wrote: > Jan Beulich wrote: > >>>> Konrad Rzeszutek Wilk 03/09/10 6:34 PM >>> > >> > >> What are you guys feeling about this patch? > > > > My main question is whether just disabling x2apic in this case is > > sufficient (i.e. whether instead we shouldn't disable iommu, or at > > least interrupt remapping, altogether). > > iommu_enable is called after this point, and it also has sanity-check to determine whether enable or disable iommu and its related features. This early check is only used to determine whether to enable x2apic because it must be enabled at very early time if supported. Exactly. So the x2APIC is turned off here and then later on the Interrupt Remaping is turned off as well.