Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755276AbZCQPzp (ORCPT ); Tue, 17 Mar 2009 11:55:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753717AbZCQPzg (ORCPT ); Tue, 17 Mar 2009 11:55:36 -0400 Received: from one.firstfloor.org ([213.235.205.2]:55231 "EHLO one.firstfloor.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753296AbZCQPzf (ORCPT ); Tue, 17 Mar 2009 11:55:35 -0400 Date: Tue, 17 Mar 2009 16:55:55 +0100 From: Andi Kleen To: Arjan van de Ven Cc: Andi Kleen , "H. Peter Anvin" , Jan Beulich , Jeremy Fitzhardinge , Jeremy Fitzhardinge , the arch/x86 maintainers , Xen-devel , Linux Kernel Mailing List Subject: Re: [Xen-devel] [PATCH 10/24] xen: mask XSAVE from cpuid Message-ID: <20090317155555.GT11935@one.firstfloor.org> References: <49BD4CE1.6040100@zytor.com> <49BD6D0E.1010107@goop.org> <20090315154718.00353625@infradead.org> <49BD97C6.2070401@goop.org> <20090315170945.08344b86@infradead.org> <49BE6D50.76E4.0078.0@novell.com> <87fxhd2f53.fsf@basil.nowhere.org> <49BEFDFB.8070900@zytor.com> <20090317115621.GQ11935@one.firstfloor.org> <20090317084928.0f17dfb0@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20090317084928.0f17dfb0@infradead.org> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1020 Lines: 27 > well the choice fundamentally is > 1) Have correct applications work, even though you might not always get > all new features that the hardware could have done.. at the expense > that someone who wants to do horrible things can > 2) Have all latest features always there, but break correctly written > apps/oses every 2 years. I'm not sure there will be that much breakage. It seems more like a theoretical danger. > > I'd go for option 1 any day of the week, hands down. > Esp if the "cpu cloaking" kind of things really disable the > instructions... but even without. With cpu cloaking and disabling unknown instructions it would be fine to go conservative. But that's not what is being proposed. -Andi -- ak@linux.intel.com -- Speaking for myself only. -- 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/