Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761489AbYBFJmS (ORCPT ); Wed, 6 Feb 2008 04:42:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760920AbYBFJl7 (ORCPT ); Wed, 6 Feb 2008 04:41:59 -0500 Received: from sca-es-mail-2.Sun.COM ([192.18.43.133]:50289 "EHLO sca-es-mail-2.sun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760847AbYBFJl5 convert rfc822-to-8bit (ORCPT ); Wed, 6 Feb 2008 04:41:57 -0500 Date: Wed, 06 Feb 2008 01:49:25 -0800 From: Yinghai Lu Subject: [PATCH] x86_32: fix regression caused by trim ram according to mtrr on system with 4G more RAM In-reply-to: <47A97E28.1010400@openvz.org> To: Ingo Molnar Cc: Pavel Emelyanov , "Kok, Auke" , jesse.brandeburg@intel.com, jeffrey.t.kirsher@intel.com, john.ronciak@intel.com, David Miller , Linux Netdev List , e1000-devel@lists.sourceforge.net, Denis Lunev , Justin Piszcz , Thomas Gleixner , Linux Kernel Mailing List Message-id: <200802060149.26083.yinghai.lu@sun.com> Organization: Sun MIME-version: 1.0 Content-type: text/plain; charset=utf-8 Content-transfer-encoding: 8BIT Content-disposition: inline References: <47A89A77.1050608@openvz.org> <200802060119.25278.yinghai.lu@sun.com> <47A97E28.1010400@openvz.org> User-Agent: KMail/1.9.6 (enterprise 20070904.708012) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2583 Lines: 80 [PATCH] x86_32: fix regression caused by trim ram according to mtrr on system with 4G more RAM Pravel report: " The commit         093af8d7f0ba3c6be1485973508584ef081e9f93         x86_32: trim memory by updating e820 broke my e1000 card: on loading driver says that         e1000: probe of 0000:04:03.0 failed with error -5 and the interface doesn't appear. " on 32 bit kernel, base will overflow when try to do PAGE_SHIFT. and highest_addr will always less 4G. so use pfn instead of address to avoid overflow when more than 4g ram installed on 32bit kernel Many thanks for Pavel Emelyanov to report and test it. Signed-off-by: Yinghai Lu Tested-by: Pavel Emelyanov diff --git a/arch/x86/kernel/cpu/mtrr/main.c b/arch/x86/kernel/cpu/mtrr/main.c index 1e27b69..4e7490f 100644 --- a/arch/x86/kernel/cpu/mtrr/main.c +++ b/arch/x86/kernel/cpu/mtrr/main.c @@ -659,7 +659,7 @@ static __init int amd_special_default_mtrr(void) */ int __init mtrr_trim_uncached_memory(unsigned long end_pfn) { - unsigned long i, base, size, highest_addr = 0, def, dummy; + unsigned long i, base, size, highest_pfn = 0, def, dummy; mtrr_type type; u64 trim_start, trim_size; @@ -682,28 +682,27 @@ int __init mtrr_trim_uncached_memory(unsigned long end_pfn) mtrr_if->get(i, &base, &size, &type); if (type != MTRR_TYPE_WRBACK) continue; - base <<= PAGE_SHIFT; - size <<= PAGE_SHIFT; - if (highest_addr < base + size) - highest_addr = base + size; + if (highest_pfn < base + size) + highest_pfn = base + size; } /* kvm/qemu doesn't have mtrr set right, don't trim them all */ - if (!highest_addr) { + if (!highest_pfn) { printk(KERN_WARNING "WARNING: strange, CPU MTRRs all blank?\n"); WARN_ON(1); return 0; } - if ((highest_addr >> PAGE_SHIFT) < end_pfn) { + if (highest_pfn < end_pfn) { printk(KERN_WARNING "WARNING: BIOS bug: CPU MTRRs don't cover" " all of memory, losing %LdMB of RAM.\n", - (((u64)end_pfn << PAGE_SHIFT) - highest_addr) >> 20); + (end_pfn - highest_pfn) >> (20 - PAGE_SHIFT)); WARN_ON(1); printk(KERN_INFO "update e820 for mtrr\n"); - trim_start = highest_addr; + trim_start = highest_pfn; + trim_start <<= PAGE_SHIFT; trim_size = end_pfn; trim_size <<= PAGE_SHIFT; trim_size -= trim_start; -- 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/