From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754903AbZDTLXo (ORCPT ); Mon, 20 Apr 2009 07:23:44 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754467AbZDTLXd (ORCPT ); Mon, 20 Apr 2009 07:23:33 -0400 Received: from mx2.redhat.com ([66.187.237.31]:40675 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754312AbZDTLXd (ORCPT ); Mon, 20 Apr 2009 07:23:33 -0400 Message-ID: <49EC5B2A.9080403@redhat.com> Date: Mon, 20 Apr 2009 13:23:22 +0200 From: Gerd Hoffmann User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1b3pre) Gecko/20090324 Fedora/3.0-2.1.beta2.fc11 Thunderbird/3.0b2 MIME-Version: 1.0 To: Avi Kivity CC: Anthony Liguori , Huang Ying , "kvm@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Andi Kleen Subject: Re: [PATCH] Add MCE support to KVM References: <1239155601.6384.3.camel@yhuang-dev.sh.intel.com> <49DE195D.1020303@redhat.com> <1239332455.6384.108.camel@yhuang-dev.sh.intel.com> <49E08762.1010206@redhat.com> <1239590499.6384.4016.camel@yhuang-dev.sh.intel.com> <49E337D7.5050502@redhat.com> <49EA515C.9000507@codemonkey.ws> <49EAE1F6.9050205@redhat.com> <49EC29D1.8040407@redhat.com> <49EC3198.9070902@redhat.com> <49EC3987.2040001@redhat.com> <49EC3AD6.3090905@redhat.com> In-Reply-To: <49EC3AD6.3090905@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/20/09 11:05, Avi Kivity wrote: > Gerd Hoffmann wrote: >> On 04/20/09 10:26, Avi Kivity wrote: >>> Gerd Hoffmann wrote: >>>> The xen pv-on-hvm drivers use an msr to indicate "please place the >>>> hypercall page here". Handling that in kernel isn't an option IMHO. >>> >>> The contents of the hypercall page are vendor specific. This can be >>> handled from userspace (though ideally we'd abstract the cpu vendor >>> away). >> >> Well, xenner doesn't do vmcalls, so the page isn't vendor specific. > > Well, for true pv (not pv-on-hvm) it wouldn't use the MSR, would it? Yes, the MSR is used for pv-on-hvm only. >> It looks different for 32bit / 64bit guests though. And it actually >> can be multiple pages (with one msr write per page). So the interface >> for in-kernel handling would be more complex than "here is a hypercall >> page for you". > > To different MSRs, or multiple writes to the same MSR? Same MSR, multiple writes (page number in the low bits). cheers, Gerd