From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Han, Weidong" Subject: RE: [RFC][PATCH] 0/9 Populate-on-demand memory Date: Fri, 26 Dec 2008 08:42:49 +0800 Message-ID: <715D42877B251141A38726ABF5CABF2C018E8961FD@pdsmsx503.ccr.corp.intel.com> References: <0A882F4D99BBF6449D58E61AAFD7EDD603BB49E5@pdsmsx502.ccr.corp.intel.com> <0A882F4D99BBF6449D58E61AAFD7EDD603BB49F5@pdsmsx502.ccr.corp.intel.com> <715D42877B251141A38726ABF5CABF2C018E8307F7@pdsmsx503.ccr.corp.intel.com> <0A882F4D99BBF6449D58E61AAFD7EDD603BB4A08@pdsmsx502.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <0A882F4D99BBF6449D58E61AAFD7EDD603BB4A08@pdsmsx502.ccr.corp.intel.com> Content-Language: en-US List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: "Tian, Kevin" , 'George Dunlap' Cc: "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org Tian, Kevin wrote: >> From: Han, Weidong >> Sent: Thursday, December 25, 2008 1:43 PM >>>>=20 >>>> At any rate, until we have that worked out, we should probably add >>>> some "seatbelt" code to make sure that people don't use PoD for a >>>> VT-d enabled domain. I know absolutely nothing about the VT-d >>>> code; could you either write a patch to do this check, or give me >>>> an idea of the simplest thing to check? >>>=20 >>> Weidong works on VT-d and could give comments on exact point to >>> check.=20 >>>=20 >>=20 >> You can simply check "iommu_enabled" to know whether IOMMU >> including VT-d and AMD IOMMU is used or not. >>=20 >=20 > Weidong, does iommu_enabled indicate IOMMU h/w availability? > Then you'll have this nice feature disabled on most new platform > with IOMMU shipped. :-) Here a domain-based check is required, > i.e. PoD is only appliable when target domain is not passthroughed > with any device. >=20 > Thanks, > Kevin iommu_enabled will be set when IOMMU h/w is available and user sets "iommu= =3D1" in grub to use it. Because device hotplug with VT-d is already suppor= ted, I think domain-based check is not enough, it's better to disable PoD w= hen iommu_enabled is set.=20 Regards, Weidong=