From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758087Ab3K0Wkm (ORCPT ); Wed, 27 Nov 2013 17:40:42 -0500 Received: from terminus.zytor.com ([198.137.202.10]:53436 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753959Ab3K0Wkl (ORCPT ); Wed, 27 Nov 2013 17:40:41 -0500 Message-ID: <529674C4.2030906@zytor.com> Date: Wed, 27 Nov 2013 14:40:04 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.1.0 MIME-Version: 1.0 To: Borislav Petkov CC: Linus Torvalds , Andy Lutomirski , Andi Kleen , Linux Kernel Mailing List , Ingo Molnar , Andi Kleen , Thomas Gleixner Subject: Re: [PATCH] Add a text_poke syscall v2 References: <1385426236-14960-1-git-send-email-andi@firstfloor.org> <5294F10C.8060901@amacapital.net> <52964EC7.9000504@zytor.com> <52966C0A.7070201@zytor.com> <20131127222104.GA748@pd.tnic> <20131127222944.GB748@pd.tnic> In-Reply-To: <20131127222944.GB748@pd.tnic> X-Enigmail-Version: 1.6 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 On 11/27/2013 02:29 PM, Borislav Petkov wrote: > On Wed, Nov 27, 2013 at 02:25:29PM -0800, H. Peter Anvin wrote: >> Actually the CPUID is superfluous on anything than the executing CPU >> since IRET is serializing. > > Why not on the executing core too? We're IRET-ting there too. > > Which would mean that a dummy empty syscall would be enough too since we > need the serialization only. > Also don't forget we need the IPIs, too... -hpa