Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753138AbZKLFid (ORCPT ); Thu, 12 Nov 2009 00:38:33 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752297AbZKLFid (ORCPT ); Thu, 12 Nov 2009 00:38:33 -0500 Received: from terminus.zytor.com ([198.137.202.10]:46383 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752182AbZKLFic (ORCPT ); Thu, 12 Nov 2009 00:38:32 -0500 Message-ID: <4AFB9DAE.4080601@zytor.com> Date: Wed, 11 Nov 2009 21:31:26 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.1) Gecko/20090814 Fedora/3.0-2.6.b3.fc11 Thunderbird/3.0b3 MIME-Version: 1.0 To: Willy Tarreau 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 References: <4AF9E61B.5090407@zytor.com> <20091110222031.GA22911@elte.hu> <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> In-Reply-To: <20091112052754.GB15679@1wt.eu> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1086 Lines: 28 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. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf. -- 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/