From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755033AbZDLFXp (ORCPT ); Sun, 12 Apr 2009 01:23:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752586AbZDLFXg (ORCPT ); Sun, 12 Apr 2009 01:23:36 -0400 Received: from terminus.zytor.com ([198.137.202.10]:37675 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752142AbZDLFXg (ORCPT ); Sun, 12 Apr 2009 01:23:36 -0400 Message-ID: <49E17A6E.5000104@zytor.com> Date: Sat, 11 Apr 2009 22:21:50 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.21 (X11/20090320) MIME-Version: 1.0 To: Avi Kivity CC: Pavel Machek , Ingo Molnar , mingo@redhat.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, hpa@linux.intel.com, rjw@sisk.pl, linux-tip-commits@vger.kernel.org, Linus Torvalds Subject: Re: [tip:x86/setup] x86, setup: "glove box" BIOS calls -- infrastructure References: <49DE7F79.4030106@zytor.com> <20090410080444.GC16512@elf.ucw.cz> <20090410103934.GA21506@elte.hu> <20090410104648.GA31516@elf.ucw.cz> <20090410112546.GD21506@elte.hu> <20090410113824.GA18823@elf.ucw.cz> <49E0C1AB.2050608@redhat.com> In-Reply-To: <49E0C1AB.2050608@redhat.com> 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 Avi Kivity wrote: > > kvm might help detecting these issues, but not in fixing them. If you > isolate the BIOS, then you've prevented corruption, but you've also > prevented it from doing whatever it is it was supposed to do. If you > give it access to memory and the rest of the system, then whatever evil > it has wrought affects the system. > > You could try to allow the BIOS access to selected pieces of memory and > hardware, virtualizing the rest, but it seems to me it would be more > like a recipe for a giant headache that a solution. > The main thing you could do is drop or virtualize memory accesses to RAM it should never access in the first place, like some BIOSes which scribble over random locations in low memory. -hpa