From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753700AbYARGey (ORCPT ); Fri, 18 Jan 2008 01:34:54 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751192AbYARGer (ORCPT ); Fri, 18 Jan 2008 01:34:47 -0500 Received: from terminus.zytor.com ([198.137.202.10]:41048 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751057AbYARGeq (ORCPT ); Fri, 18 Jan 2008 01:34:46 -0500 Message-ID: <479046BA.7090903@zytor.com> Date: Fri, 18 Jan 2008 01:27:06 -0500 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.9 (X11/20071115) MIME-Version: 1.0 To: Kyle McMartin CC: Andi Kleen , tglx@linutronix.de, mingo@redhat.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86: make clflush a required feature on x86_64 References: <20080118045921.GB974@phobos.i.cabal.ca> <20080118060124.GC1726@phobos.i.cabal.ca> In-Reply-To: <20080118060124.GC1726@phobos.i.cabal.ca> 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 Kyle McMartin wrote: > On Fri, Jan 18, 2008 at 06:53:53AM +0100, Andi Kleen wrote: >> One problem that we had in the past is that some simulators >> only implement the absolutely minimum feature set and you >> might have well broken one of these with this. > > Yeah, true. Please ignore the patch folks. > > cheers, Kyle Simulators can be fixed, even if it takes time; for something like clflush this is easier since clflush can be implemented as a simple noop for most of them. I just verified that Bochs 2.3.0 lacks this CPUID bit whereas the current version, 2.3.6, enables CLFLUSH iff SSE2 is enabled. Qemu 0.9.0 has CLFLUSH. Andi, do you happen to know of any specific simulators which are problematic? I would assume any recent version of SimNow is up to date. -hpa