From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752558Ab1ADQ7n (ORCPT ); Tue, 4 Jan 2011 11:59:43 -0500 Received: from mtaout02-winn.ispmail.ntl.com ([81.103.221.48]:21274 "EHLO mtaout02-winn.ispmail.ntl.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752520Ab1ADQ7l (ORCPT ); Tue, 4 Jan 2011 11:59:41 -0500 From: Ian Campbell To: Konrad Rzeszutek Wilk Cc: "linux-kernel@vger.kernel.org" , Jeremy Fitzhardinge , "hpa@zytor.com" , Jan Beulich , "xen-devel@lists.xensource.com" , Konrad Rzeszutek Wilk , Stefano Stabellini In-Reply-To: <1294160028.3831.563.camel@zakaz.uk.xensource.com> References: <1293738517-7287-1-git-send-email-konrad.wilk@oracle.com> <1293738517-7287-3-git-send-email-konrad.wilk@oracle.com> <1294160028.3831.563.camel@zakaz.uk.xensource.com> Content-Type: text/plain; charset="UTF-8" Date: Tue, 04 Jan 2011 16:59:19 +0000 Message-ID: <1294160359.3831.579.camel@zakaz.uk.xensource.com> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 7bit X-SA-Exim-Connect-IP: 62.200.22.2 X-SA-Exim-Mail-From: ijc@hellion.org.uk Subject: Re: [PATCH 2/8] xen/mmu: Add the notion of identity (1-1) mapping. X-SA-Exim-Version: 4.2.1 (built Wed, 25 Jun 2008 17:14:11 +0000) X-SA-Exim-Scanned: Yes (on hopkins.hellion.org.uk) X-Cloudmark-Analysis: v=1.1 cv=JvdXmxIgLJv2/GthKqHpGJEEHukvLcvELVXUanXFreg= c=1 sm=0 a=ElWBgQNHElIA:10 a=IkcTkHD0fZMA:10 a=9LK883MKfsj71dkQuIQA:9 a=CaDgvDK8YC45D16O3xoA:7 a=RhISWYyJmt0_V-3-_z7vjSDvwRYA:4 a=QEXdDO2ut3YA:10 a=19jjMibb8a9Jz_zD:21 a=L1hc0XvolwldEPdj:21 a=HpAAvcLHHh0Zw7uRqdWCyQ==:117 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2011-01-04 at 16:53 +0000, Ian Campbell wrote: > > If I do "__set_phys_to_machine(X, X)" where X happens to currently > correspond to p2m_mid_missing won't that cause all pfn entries in the > range covered by p2m_top[topidx] (i.e. quite a few, like 512^2 pages > or > something) to switch from missing to identity? Similarly for > p2m_top[topidx][mididx]? > > Perhaps ranges of identity bits are often well aligned with the > boundaries in the p2m 3-level tree but wouldn't that just be > coincidence? I wonder if it would make sense to have a debugfs file which exports the p2m, for the purposes of eye-balling it for this sort of issue? comparing to the e820 etc... Maybe the whole thing in raw form would be overkill but spitting out a list of ranges of identity, invalid, normal pages, plus annotation regarding whether those come from a p2m_mid_identity style page or a leaf node, might be occasionally useful. Ian. -- Ian Campbell Current Noise: Place of Skulls - The Watchers Call toll free number before digging.