From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757405AbYAJBGL (ORCPT ); Wed, 9 Jan 2008 20:06:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754209AbYAJBF6 (ORCPT ); Wed, 9 Jan 2008 20:05:58 -0500 Received: from mx1.redhat.com ([66.187.233.31]:55641 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754012AbYAJBF5 (ORCPT ); Wed, 9 Jan 2008 20:05:57 -0500 Date: Wed, 9 Jan 2008 20:05:31 -0500 From: Vivek Goyal To: "Huang, Ying" Cc: "Eric W. Biederman" , Andrew Morton , linux-kernel@vger.kernel.org, Horms , magnus.damn@gmail.com Subject: Re: [PATCH -mm 2/2] kexec/i386: kexec page table code clean up - page table setup in C Message-ID: <20080110010531.GA23143@redhat.com> References: <1199847470.8126.16.camel@caritas-dev.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1199847470.8126.16.camel@caritas-dev.intel.com> User-Agent: Mutt/1.5.17 (2007-11-01) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jan 09, 2008 at 10:57:50AM +0800, Huang, Ying wrote: > This patch transforms the kexec page tables setup code from asseumbler > code to iC code in machine_kexec_prepare. This improves readability and > reduces code line number. > I think this will create issues for Xen. Initially page table setup was in C but Xen Guests could not modify the page tables. I think Xen folks implemented a hypercall where they passed all the page table pages and the control pages and then hypervisor executed the control page(which in turn setup the page tables). I think that's why page table setup code is on the control page in assembly. You might want to go through Xen kexec implementation and dig through kexec mailing list archive. CCing Magnus and Horms. They had done the page tables related changes for Xen. Thanks Vivek