From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751683AbcBYVF3 (ORCPT ); Thu, 25 Feb 2016 16:05:29 -0500 Received: from mga14.intel.com ([192.55.52.115]:44733 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750731AbcBYVF2 (ORCPT ); Thu, 25 Feb 2016 16:05:28 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.22,498,1449561600"; d="scan'208";a="924005828" Date: Thu, 25 Feb 2016 13:03:03 -0800 From: Yu-cheng Yu To: Dave Hansen Cc: x86@kernel.org, "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, Andy Lutomirski , Borislav Petkov , Sai Praneeth Prakhya , "Ravi V. Shankar" , Fenghua Yu Subject: Re: [PATCH v2 9/9] x86/xsaves: Re-enable XSAVES Message-ID: <20160225210303.GA8924@test-lenovo> References: <8687eb3f43f4a2a4cc2c21f38c5f420631662fd3.1456420312.git.yu-cheng.yu@intel.com> <56CF6573.1040604@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <56CF6573.1040604@linux.intel.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 25, 2016 at 12:34:59PM -0800, Dave Hansen wrote: > On 02/25/2016 12:26 PM, Yu-cheng Yu wrote: > > - * ( This is easy to backport while we are fixing > > - * XSAVES* support. ) > > + * Most recent CPUs supporting XSAVES can run 64-bit mode. > > + * Enable XSAVES for 64-bit. > > */ > > - setup_clear_cpu_cap(X86_FEATURE_XSAVES); > > + if (!config_enabled(CONFIG_X86_64)) > > + setup_clear_cpu_cap(X86_FEATURE_XSAVES); > > } > > Is this intended to be permanent? If so, we would not be able to > support any future supervisor features on 32-bit. I was thinking of the 64-bit-only change, but then decided to put it out for discussion. Yu-cheng