Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759772AbZKLBAK (ORCPT ); Wed, 11 Nov 2009 20:00:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1759745AbZKLBAJ (ORCPT ); Wed, 11 Nov 2009 20:00:09 -0500 Received: from ppp59-167-189-244.static.internode.on.net ([59.167.189.244]:38636 "EHLO isinu.rimspace.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759690AbZKLBAI convert rfc822-to-8bit (ORCPT ); Wed, 11 Nov 2009 20:00:08 -0500 X-Greylist: delayed 492 seconds by postgrey-1.27 at vger.kernel.org; Wed, 11 Nov 2009 20:00:06 EST From: Daniel Pittman To: "H. Peter Anvin" Cc: Alan Cox , Avi Kivity , Willy Tarreau , Pavel Machek , Matteo Croce , Sven-Haegar Koch , Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: i686 quirk for AMD Geode References: <4AF4526B.4060101@zytor.com> <40101cc30911061418w357b74d8i3bf9a9537de052d4@mail.gmail.com> <20091108173708.GF1372@ucw.cz> <40101cc30911080940s18eb26bbg641beeaddbc25c3d@mail.gmail.com> <20091108181016.GB32364@elf.ucw.cz> <20091108193618.GB4186@elf.ucw.cz> <40101cc30911081147j77f7b81o86f2cc5a869aca1f@mail.gmail.com> <20091108195158.GD4186@elf.ucw.cz> <20091108200852.7f2cf092@lxorguk.ukuu.org.uk> <20091110052711.GA15338@1wt.eu> <4AF9020C.90108@zytor.com> <4AF9435F.2070103@redhat.com> <20091110105642.215804e0@lxorguk.ukuu.org.uk> <4AF99E04.8080704@zytor.com> <20091110172454.3c4481f2@lxorguk.ukuu.org.uk> <4AF9B5AB.5010800@zytor.com> Date: Thu, 12 Nov 2009 11:51:55 +1100 In-Reply-To: <4AF9B5AB.5010800@zytor.com> (H. Peter Anvin's message of "Tue, 10 Nov 2009 10:49:15 -0800") Message-ID: <87zl6sva38.fsf@rimspace.net> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1949 Lines: 43 "H. Peter Anvin" writes: > On 11/10/2009 09:24 AM, Alan Cox wrote: >>> >>> In the short term, yes, of course. However, if we're going to do >>> emulation, we might as well do it right. >> >> Why is using KVM doing it right ? It sounds like its doing it slowly, >> and hideously memory inefficiently. You are solving an uninteresting >> general case problem when you just need two tiny fixups (or perhaps 3 if >> you want to fix up early x86-64 prefetch) > > Why do we only need "two tiny fixups"? Where do we draw the line in > terms of ISA compatibility? One could easily argue that the Right > Thing[TM] is to be able to process any optional instruction -- otherwise > one has a very difficult place to draw a line. > > Consider SSE3, for example. Why should the same concept not apply to > SSE3 instructions as to CMOV? FWIW, the issue of the binary-only flashplayer.so came up later in the thread, but to add my few cents: When flash 10 was released the binary only 64-bit version generated instructions from the LAHF set unconditionally, in part because Windows chose to emulate those on the very few x86-64 platforms that didn't do them in hardware. At that time it would have been very nice from a "user support" point of view to be able to add LAHF emulation to support the software. Yes, it is ugly, binary-only code, but it is reasonably popular... Daniel ...in the end, in fact, popular enough to have at least a couple of people I know purchase a new CPU that did implement it, just for flash on Linux. -- ✣ Daniel Pittman ✉ daniel@rimspace.net ☎ +61 401 155 707 ♽ made with 100 percent post-consumer electrons -- 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/