From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752028AbbBXGpO (ORCPT ); Tue, 24 Feb 2015 01:45:14 -0500 Received: from cantor2.suse.de ([195.135.220.15]:40175 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750752AbbBXGpN (ORCPT ); Tue, 24 Feb 2015 01:45:13 -0500 Message-ID: <54EC1DF6.8090904@suse.com> Date: Tue, 24 Feb 2015 07:45:10 +0100 From: Juergen Gross User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.4.0 MIME-Version: 1.0 To: David Vrabel , linux-kernel@vger.kernel.org, xen-devel@lists.xensource.com, konrad.wilk@oracle.com, david.vrabel@citrix.com, boris.ostrovsky@oracle.com Subject: Re: [Xen-devel] [PATCH 09/13] xen: check for kernel memory conflicting with memory layout References: <1424242326-26611-1-git-send-email-jgross@suse.com> <1424242326-26611-10-git-send-email-jgross@suse.com> <54E61F10.9010808@cantab.net> In-Reply-To: <54E61F10.9010808@cantab.net> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/19/2015 06:36 PM, David Vrabel wrote: > On 18/02/2015 06:52, Juergen Gross wrote: >> Checks whether the pre-allocated memory of the loaded kernel is in >> conflict with the target memory map. If this is the case, just panic >> instead of run into problems later. > > What ensures this doesn't actually happen? Nothing. We have basically three options here: - Die early (my patch). - Issue a warning that the critical situation has been detected and hope for the best by not doing the remap, but probably run into strange situations when the discrepancy between E820 map and memory usage is becoming problematic. - Do the remap like today and die eventually when the relocated page is used for p2m/m2p translations (no real option). Juergen