From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759156AbYJJLBO (ORCPT ); Fri, 10 Oct 2008 07:01:14 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754618AbYJJLA7 (ORCPT ); Fri, 10 Oct 2008 07:00:59 -0400 Received: from mx3.mail.elte.hu ([157.181.1.138]:60273 "EHLO mx3.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754491AbYJJLA6 (ORCPT ); Fri, 10 Oct 2008 07:00:58 -0400 Date: Fri, 10 Oct 2008 13:00:38 +0200 From: Ingo Molnar To: Ian Campbell Cc: linux-kernel@vger.kernel.org, Jeremy Fitzhardinge , Thomas Gleixner , "H. Peter Anvin" , Yinghai Lu Subject: Re: [PATCH] xen: do not reserve 2 pages of padding between hypervisor and fixmap. Message-ID: <20081010110038.GB4699@elte.hu> References: <1223634458-25820-1-git-send-email-Ian.Campbell@citrix.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1223634458-25820-1-git-send-email-Ian.Campbell@citrix.com> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00,DNS_FROM_SECURITYSAGE autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] 0.0 DNS_FROM_SECURITYSAGE RBL: Envelope sender in blackholes.securitysage.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Ian Campbell wrote: > When reserving space for the hypervisor the Xen paravirt backend adds > an extra two pages (this was carried forward from the 2.6.18-xen tree > which had them "for safety"). Depending on various CONFIG options this > can cause the boot time fixmaps to span multiple PMDs which is not > supported and triggers a WARN in early_ioremap_init(). > > This was exposed by 2216d199b1430d1c0affb1498a9ebdbd9c0de439 which > moved the dmi table parsing earlier. > x86: fix CONFIG_X86_RESERVE_LOW_64K=y > > The bad_bios_dmi_table() quirk never triggered because we do DMI setup > too late. Move it a bit earlier. > > There is no real reason to reserve these two extra pages and the > fixmap already incorporates FIX_HOLE which serves the same > purpose. None of the other callers of reserve_top_address do this. > > Signed-off-by: Ian Campbell > Cc: Jeremy Fitzhardinge > Cc: Signed-off-by: Ingo Molnar applied to tip/x86/xen, thanks Ian! Ingo