From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: Re: Xen: Hybrid extension patchset for hypervisor Date: Thu, 17 Sep 2009 10:19:47 -0700 Message-ID: <4AB26FB3.4070600@goop.org> References: <0B53E02A2965CE4F9ADB38B34501A3A1940C78A8@orsmsx505.amr.corp.intel.com> <4AB12C1F.9080502@goop.org> <1253135571.3896.4873.camel@localhost.localdomain> <4AB15707.20305@goop.org> <1253178985.16152.26.camel@zakaz.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1253178985.16152.26.camel@zakaz.uk.xensource.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: Ian Campbell Cc: "Yang, Sheng" , "xen-devel@lists.xensource.com" , "Dong, Eddie" , Keir Fraser , "Nakajima, Jun" List-Id: xen-devel@lists.xenproject.org On 09/17/09 02:16, Ian Campbell wrote: > In practise, at least for the 2.6.18-xen tree (which is the only one > where I expect it was ever completely implemented), it is only used to > set the kernel CS and DS and to gate sysenter setup (for which I think > we have a better mechanism today) but you are right that in principle it > could be more far reaching than that. > Yeah. Looks like the only other thing it allows is that the guest can set arbitrary gdt entries. >> Making use of XENFEAT_auto_translated_physmap would avoid the need for >> identity p2m/m2p tables, but I'm not sure whether it still works. I got >> close to completely removing all references to it at one point, but I >> think ia64 uses it? >> > I very much expect that it'll need fixing/(re)implementing on both the > kernel and hypervisor side... > Yeah, I think the Xen side is missing altogether on x86 now. I don't think its worth recovering it unless its the ABI for making HAP available to guests. If IA64 is using it, then I think big parts of the kernel are probably in OK shape (drivers, etc). J