From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C6F31C0650E for ; Mon, 1 Jul 2019 16:39:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 99A90216F4 for ; Mon, 1 Jul 2019 16:39:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729420AbfGAQj0 (ORCPT ); Mon, 1 Jul 2019 12:39:26 -0400 Received: from mga05.intel.com ([192.55.52.43]:25953 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729348AbfGAQjZ (ORCPT ); Mon, 1 Jul 2019 12:39:25 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 01 Jul 2019 09:39:25 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.63,440,1557212400"; d="scan'208";a="361893750" Received: from tassilo.jf.intel.com (HELO tassilo.localdomain) ([10.7.201.137]) by fmsmga005.fm.intel.com with ESMTP; 01 Jul 2019 09:39:25 -0700 Received: by tassilo.localdomain (Postfix, from userid 1000) id 0B15F30120F; Mon, 1 Jul 2019 09:39:25 -0700 (PDT) Date: Mon, 1 Jul 2019 09:39:24 -0700 From: Andi Kleen To: Vegard Nossum Cc: Andi Kleen , x86@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v8 4/5] x86/xsave: Make XSAVE check the base CPUID features before enabling Message-ID: <20190701163924.GB31027@tassilo.jf.intel.com> References: <20171005215256.25659-1-andi@firstfloor.org> <20171005215256.25659-5-andi@firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.11.3 (2019-02-01) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > The commit for this patch in mainline > (ccb18db2ab9d923df07e7495123fe5fb02329713) causes the kernel to hang on > boot when passing the "nofxsr" option: Thanks. Hmm, I'm not sure nofxsr ever worked on 64bit. Certainly SSE cannot be saved/restored in any other way during the context switch. So even if you pass it successfully I doubt user space will really work for very long. 64bit binaries require SSE. AFAIK it is only useful on systems without SSE, presumably running 32bit kernels. Should check that case. My recommended solution would be to just get rid of the option. Presumably it's just some old chicken bit. -Anfi