From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932401AbcFNUrm (ORCPT ); Tue, 14 Jun 2016 16:47:42 -0400 Received: from mail.skyhub.de ([78.46.96.112]:41852 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932082AbcFNUrk (ORCPT ); Tue, 14 Jun 2016 16:47:40 -0400 Date: Tue, 14 Jun 2016 22:47:36 +0200 From: Borislav Petkov To: "H. Peter Anvin" Cc: Dave Hansen , One Thousand Gnomes , Lukasz Anaczkowski , linux-kernel@vger.kernel.org, linux-mm@kvack.org, tglx@linutronix.de, mingo@redhat.com, ak@linux.intel.com, kirill.shutemov@linux.intel.com, mhocko@suse.com, akpm@linux-foundation.org, harish.srinivasappa@intel.com, lukasz.odzioba@intel.com, grzegorz.andrejczuk@intel.com, lukasz.daniluk@intel.com Subject: Re: [PATCH v2] Linux VM workaround for Knights Landing A/D leak Message-ID: <20160614204736.GL30015@pd.tnic> References: <7FB15233-B347-4A87-9506-A9E10D331292@gmail.com> <1465923672-14232-1-git-send-email-lukasz.anaczkowski@intel.com> <57603DC0.9070607@linux.intel.com> <20160614193407.1470d998@lxorguk.ukuu.org.uk> <576052E0.3050408@linux.intel.com> <20160614191916.GI30015@pd.tnic> <4b2c481e-35ae-1cd6-ca58-1535bfef346c@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <4b2c481e-35ae-1cd6-ca58-1535bfef346c@zytor.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 14, 2016 at 01:20:06PM -0700, H. Peter Anvin wrote: > static_cpu_has_bug() should turn into 5-byte NOP in the common (bugless) > case. Yeah, it does. I looked at the asm. I wasn't 100% sure because I vaguely remember gcc reordering things in some pathological case but I'm most likely remembering wrong because if it were doing that, then the whole nopping out won't work. F'get about it. :) -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply.