From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755641Ab2GaQZo (ORCPT ); Tue, 31 Jul 2012 12:25:44 -0400 Received: from mga03.intel.com ([143.182.124.21]:42199 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755558Ab2GaQZn (ORCPT ); Tue, 31 Jul 2012 12:25:43 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="175339310" Subject: Re: [patch] x86, avx: don't use avx instructions with "noxsave" boot param From: Suresh Siddha Reply-To: Suresh Siddha To: "H. Peter Anvin" Cc: NeilBrown , james.t.kukunas@linux.intel.com, LKML Date: Tue, 31 Jul 2012 09:27:01 -0700 In-Reply-To: <7b101443-b8d7-4474-ab54-03692d232469@email.android.com> References: <1343688375.3696.597.camel@sbsiddha-desk.sc.intel.com> <20120731142049.7d0ab5f9@notabene.brown> <7b101443-b8d7-4474-ab54-03692d232469@email.android.com> Organization: Intel Corp Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.0.3 (3.0.3-1.fc15) Content-Transfer-Encoding: 7bit Message-ID: <1343752022.3696.602.camel@sbsiddha-desk.sc.intel.com> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2012-07-30 at 21:33 -0700, H. Peter Anvin wrote: > I'm wondering if we shouldn't just kill the affected CPUID bits if osxsave is off... Yes, I considered clearing AVX bit (and any future xsave feature bits) as part of the parsing "noxsave" parameter in x86_xsave_setup(). But thought checking for osxsave was more explicit and there are not many places using avx code. Also, this follows the SDM guidelines and sets a nice precedent for someone (app's) to follow in future. I am ok either way! thanks, suresh