Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753283AbZKLFkR (ORCPT ); Thu, 12 Nov 2009 00:40:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752675AbZKLFkQ (ORCPT ); Thu, 12 Nov 2009 00:40:16 -0500 Received: from 1wt.eu ([62.212.114.60]:51045 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752297AbZKLFkP (ORCPT ); Thu, 12 Nov 2009 00:40:15 -0500 Date: Thu, 12 Nov 2009 06:40:04 +0100 From: Willy Tarreau To: "H. Peter Anvin" Cc: Matt Thrailkill , Ingo Molnar , Pavel Machek , Avi Kivity , Alan Cox , Matteo Croce , Sven-Haegar Koch , linux-kernel@vger.kernel.org Subject: Re: i686 quirk for AMD Geode Message-ID: <20091112054004.GA15925@1wt.eu> References: <20091110224222.GA28648@1wt.eu> <4AF9ED78.3000106@zytor.com> <20091111055220.GA560@1wt.eu> <4AFA569E.9040206@zytor.com> <20091111063617.GD560@1wt.eu> <4AFA6E50.7030808@zytor.com> <20091111093258.GE560@1wt.eu> <20091112052754.GB15679@1wt.eu> <4AFB9DAE.4080601@zytor.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4AFB9DAE.4080601@zytor.com> User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1399 Lines: 31 On Wed, Nov 11, 2009 at 09:31:26PM -0800, H. Peter Anvin wrote: > On 11/11/2009 09:27 PM, Willy Tarreau wrote: > > > > Right. However we just noticed that with the KVM emulator, you > > can make it loop for a long time if you feed it with prefixes > > only. For instance, write a function which does zillions of 0x66 > > (data size prefix) then return (0xC3) : 66 66 66 ... 66 C3. > > > > This is typically the sort of things we must be very careful about > > in emulators, because we don't want users to steal large amounts > > of system CPU time doing nothing. > > > > That is a (serious) bug in the KVM interpreter, and indeed the exact > kind of issues interpreters tend to have... which is why I'd like one > piece of code with one set of bugs, and more eyeballs on that one piece > of code so they can be fixed. Well, I could try to work on a fix (basically the same principle as in mine, with prefix flags), but I simply don't know how to test the code. I've never experimented with KVM yet and learned it embeds an emulator for the first time a few days ago in this thread :-/ If it's easy to make use of it, I'm not opposed to try. Willy -- 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/