Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759475AbYCEQM7 (ORCPT ); Wed, 5 Mar 2008 11:12:59 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1758526AbYCEQMs (ORCPT ); Wed, 5 Mar 2008 11:12:48 -0500 Received: from terminus.zytor.com ([198.137.202.10]:33024 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758407AbYCEQMo (ORCPT ); Wed, 5 Mar 2008 11:12:44 -0500 Message-ID: <47CEC561.6050008@zytor.com> Date: Wed, 05 Mar 2008 08:08:01 -0800 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.12 (X11/20080226) MIME-Version: 1.0 To: Eduardo Habkost CC: Ian Campbell , Alexander van Heukelum , Ingo Molnar , Alexander van Heukelum , Andi Kleen , Thomas Gleixner , Jeremy Fitzhardinge , Mark McLoughlin , LKML Subject: Re: [RFC] use realmode code to reserve end-of-conventional-memory to 1MB References: <20080224174605.GA21661@mailshack.com> <47C22568.1010405@zytor.com> <1203958478.20033.1239002461@webmail.messagingengine.com> <20080225170134.GA15839@elte.hu> <20080225180750.GA31054@mailshack.com> <20080228131341.GA25213@mailshack.com> <20080228132822.GA25278@mailshack.com> <1204233131.28798.12.camel@cthulhu.hellion.org.uk> <47C72432.3010606@zytor.com> <1204240609.28798.33.camel@cthulhu.hellion.org.uk> <20080305155930.GI20230@blackpad> In-Reply-To: <20080305155930.GI20230@blackpad> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1118 Lines: 30 Eduardo Habkost wrote: >> >> diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c >> index 3bad477..2341492 100644 >> --- a/arch/x86/xen/setup.c >> +++ b/arch/x86/xen/setup.c >> @@ -38,7 +38,8 @@ char * __init xen_memory_setup(void) >> unsigned long max_pfn = xen_start_info->nr_pages; >> >> e820.nr_map = 0; >> - add_memory_region(0, PFN_PHYS(max_pfn), E820_RAM); >> + add_memory_region(0, LOWMEMSIZE(), E820_RAM); >> + add_memory_region(HIGH_MEMORY, PFN_PHYS(max_pfn)-HIGH_MEMORY, E820_RAM); > > Won't this waste 300+ KB of Perfectly Good RAM? Or I understood it > incorrectly? > > I am aware that it would take more work to tell all kernel code that it > shouldn't look for BIOS data on this region when running as a domU guest, > but it seems that it would be a better solution. > No, the right thing is for Xen to not try to map RAM in this area. -hpa -- 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/