From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162635Ab1FAIrJ (ORCPT ); Wed, 1 Jun 2011 04:47:09 -0400 Received: from cantor2.suse.de ([195.135.220.15]:44033 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1162587Ab1FAIWB (ORCPT ); Wed, 1 Jun 2011 04:22:01 -0400 X-Mailbox-Line: From linux@blue.kroah.org Wed Jun 1 17:11:36 2011 Message-Id: <20110601081136.267713565@blue.kroah.org> User-Agent: quilt/0.48-16.4 Date: Wed, 01 Jun 2011 17:10:48 +0900 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Joerg Roedel , "Rafael J. Wysocki" , Maciej Rutecki , Avi Kivity , Ingo Molnar , Greg Kroah-Hartman Subject: [078/165] x86, amd: Use _safe() msr access for GartTlbWlk disable code In-Reply-To: <20110601081349.GA10017@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.39-stable review patch. If anyone has any objections, please let us know. ------------------ Content-Length: 1570 Lines: 55 From: "Roedel, Joerg" commit d47cc0db8fd6011de2248df505fc34990b7451bf upstream. The workaround for Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=33012 introduced a read and a write to the MC4 mask msr. Unfortunatly this MSR is not emulated by the KVM hypervisor so that the kernel will get a #GP and crashes when applying this workaround when running inside KVM. This issue was reported as: https://bugzilla.kernel.org/show_bug.cgi?id=35132 and is fixed with this patch. The change just let the kernel ignore any #GP it gets while accessing this MSR by using the _safe msr access methods. Reported-by: Török Edwin Signed-off-by: Joerg Roedel Cc: Rafael J. Wysocki Cc: Maciej Rutecki Cc: Avi Kivity Cc: Andrew Morton Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/cpu/amd.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -632,10 +632,13 @@ static void __cpuinit init_amd(struct cp * Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=33012 */ u64 mask; + int err; - rdmsrl(MSR_AMD64_MCx_MASK(4), mask); - mask |= (1 << 10); - wrmsrl(MSR_AMD64_MCx_MASK(4), mask); + err = rdmsrl_safe(MSR_AMD64_MCx_MASK(4), &mask); + if (err == 0) { + mask |= (1 << 10); + checking_wrmsrl(MSR_AMD64_MCx_MASK(4), mask); + } } }