From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933230AbXCHTym (ORCPT ); Thu, 8 Mar 2007 14:54:42 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S933232AbXCHTym (ORCPT ); Thu, 8 Mar 2007 14:54:42 -0500 Received: from mtaout4.012.net.il ([84.95.2.10]:60993 "EHLO mtaout4.012.net.il" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933230AbXCHTyl (ORCPT ); Thu, 8 Mar 2007 14:54:41 -0500 Date: Thu, 08 Mar 2007 21:44:38 +0200 From: Avi Kivity Subject: Re: [patch] disable NMI watchdog by default In-reply-to: <45EC3F25.5060308@tmr.com> To: Bill Davidsen Cc: Ingo Molnar , Andi Kleen , linux-kernel@vger.kernel.org Message-id: <45F067A6.8090707@argo.co.il> MIME-version: 1.0 Content-type: text/plain; charset=ISO-8859-1; format=flowed Content-transfer-encoding: 7BIT X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-2.1.12 (firebolt.argo.co.il [0.0.0.0]); Thu, 08 Mar 2007 21:44:38 +0200 (IST) References: <20070114092926.GA14465@elte.hu> <45EC3F25.5060308@tmr.com> User-Agent: Thunderbird 1.5.0.9 (X11/20070212) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Bill Davidsen wrote: >> >> there's a new NMI watchdog related problem: KVM crashes on certain >> bzImages because ... we enable the NMI watchdog by default (even if >> the user does not ask for it) , and no other OS on this planet does >> that so KVM doesnt have emulation for that yet. So KVM injects a #GP, >> which crashes the Linux guest: >> > I'm missing something, what limits this to systems running under kvm? > Most likely kvm doesn't implement the msrs which drive the nmi watchdog. That makes it a kvm bug, not a problem with the nmi watchdog. Emulating it correctly is fairly difficult, though, especially if we want to migrate virtual machines between different processor models, so I hope this goes in. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.