Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763154AbYBZRIT (ORCPT ); Tue, 26 Feb 2008 12:08:19 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752885AbYBZRIJ (ORCPT ); Tue, 26 Feb 2008 12:08:09 -0500 Received: from mx1.redhat.com ([66.187.233.31]:49797 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752833AbYBZRII (ORCPT ); Tue, 26 Feb 2008 12:08:08 -0500 Subject: Re: 2.6.25-rc1 xen pvops regression From: Mark McLoughlin Reply-To: Mark McLoughlin To: Ian Campbell Cc: "H. Peter Anvin" , Jeremy Fitzhardinge , Joel Becker , Jody Belka , linux-kernel@vger.kernel.org, Ingo Molnar , Thomas Gleixner , "Eric W. Biederman" , Andi Kleen , Mika Penttila In-Reply-To: <1203665106.28436.19.camel@cthulhu.hellion.org.uk> References: <20080212235404.GY7980@pimb.org> <47B2DBA5.6030001@goop.org> <20080214022744.GA4160@mail.oracle.com> <47B3F2DC.8080707@goop.org> <20080215202336.GE26034@mail.oracle.com> <1203274161.27987.6.camel@localhost.localdomain> <20080218104025.GA15899@ca-server1.us.oracle.com> <1203458366.26910.15.camel@cthulhu.hellion.org.uk> <47BBDA20.8030105@zytor.com> <1203497511.26910.39.camel@cthulhu.hellion.org.uk> <47BCA275.7000504@goop.org> <1203546597.26910.74.camel@cthulhu.hellion.org.uk> <47BDEA11.6010302@goop.org> <47BDEB57.5040203@zytor.com> <47BDEF36.8000903@goop.org> <1203631956.28436.4.camel@cthulhu.hellion.org.uk> <47BDF9C7.6040400@zytor.com> <47BE0017.1020205@goop.org> <47BE0228.7020204@zytor.com> <1203665106.28436.19.camel@cthulhu.hellion.org.uk> Content-Type: text/plain Date: Tue, 26 Feb 2008 17:06:32 +0000 Message-Id: <1204045592.12238.6.camel@muff> Mime-Version: 1.0 X-Mailer: Evolution 2.12.3 (2.12.3-1.fc8) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1719 Lines: 48 On Fri, 2008-02-22 at 07:25 +0000, Ian Campbell wrote: > On Thu, 2008-02-21 at 14:58 -0800, H. Peter Anvin wrote: > > > > Which it is on real hardware, because although it's not *reserved* > > (type 2), it is certainly not made available as *normal memory* (type > > 1). If Xen maps this as type 1 then I definitely see the problem. > > > > We can exclude type 1 memory from DMI scan, certainly. > > I'd been meaning to ask this. So the machines you have which don't > describe 0xf0000 as reserved also don't describe it as RAM? (I guess > it's either a hole in the table or one of the other e820 types). > Ian. ... > >From 13bdb4ee9d80b83a81c3dbefa52464e511d1b4df Mon Sep 17 00:00:00 2001 > From: Ian Campbell > Date: Fri, 22 Feb 2008 07:17:14 +0000 > Subject: [PATCH] x86: Do not scan for DMI if the DMI region is marked as RAM by e820. > > Under Xen the memory at 0xf0000 is regular RAM and so can potentially contain a > page table and hence cannot be mapped. The e820 map given to guest reflects > this. > > Signed-off-by: Ian Campbell ... > @@ -371,6 +372,9 @@ void __init dmi_scan_machine(void) > } > } > else { > + if (e820_all_mapped(0xF0000, 0xF0000+0x10000, E820_RAM)) > + goto out; One issue with using the e820 map for this is that a Xen Dom0 will also have this region marked as RAM in the e820 map, but will set up a fixmap for it, allowing dmi_scan_machine() to map the region. Cheers, Mark. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/