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=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 AB61AC43603 for ; Thu, 19 Dec 2019 00:42:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8894D222C2 for ; Thu, 19 Dec 2019 00:42:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726634AbfLSAm2 (ORCPT ); Wed, 18 Dec 2019 19:42:28 -0500 Received: from mga04.intel.com ([192.55.52.120]:27288 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726518AbfLSAm2 (ORCPT ); Wed, 18 Dec 2019 19:42:28 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 18 Dec 2019 16:42:27 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,330,1571727600"; d="scan'208";a="228071463" Received: from jtreacy-mobl1.ger.corp.intel.com ([10.251.82.127]) by orsmga002.jf.intel.com with ESMTP; 18 Dec 2019 16:42:20 -0800 Message-ID: Subject: Re: [PATCH v24 07/24] x86/cpu/intel: Detect SGX supprt From: Jarkko Sakkinen To: Borislav Petkov Cc: linux-kernel@vger.kernel.org, x86@kernel.org, linux-sgx@vger.kernel.org, akpm@linux-foundation.org, dave.hansen@intel.com, sean.j.christopherson@intel.com, nhorman@redhat.com, npmccallum@redhat.com, serge.ayoun@intel.com, shay.katz-zamir@intel.com, haitao.huang@intel.com, andriy.shevchenko@linux.intel.com, tglx@linutronix.de, kai.svahn@intel.com, josh@joshtriplett.org, luto@kernel.org, kai.huang@intel.com, rientjes@google.com, cedric.xing@intel.com, puiterwijk@redhat.com Date: Thu, 19 Dec 2019 02:42:20 +0200 In-Reply-To: <20191217151744.GG28788@zn.tnic> References: <20191129231326.18076-1-jarkko.sakkinen@linux.intel.com> <20191129231326.18076-8-jarkko.sakkinen@linux.intel.com> <20191217151744.GG28788@zn.tnic> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.34.1-2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On Tue, 2019-12-17 at 16:17 +0100, Borislav Petkov wrote: > On Sat, Nov 30, 2019 at 01:13:09AM +0200, Jarkko Sakkinen wrote: > > Typo in the subject: > > Subject: Re: [PATCH v24 07/24] x86/cpu/intel: Detect SGX supprt > ^^^^^^ > > From: Sean Christopherson > > > > When the CPU supports SGX, check that the BIOS has enabled SGX and SGX1 > > opcodes are available. Otherwise, all the SGX related capabilities. > > > > In addition, clear X86_FEATURE_SGX_LC also in the case when the launch > > enclave are read-only. This way the feature bit reflects the level that > > Linux supports the launch control. > > > > The check is done for every CPU, not just BSP, in order to verify that > > MSR_IA32_FEATURE_CONTROL is correctly configured on all CPUs. The other > > parts of the kernel, like the enclave driver, expect the same > > configuration from all CPUs. > > > > Signed-off-by: Sean Christopherson > > Co-developed-by: Jarkko Sakkinen > > Signed-off-by: Jarkko Sakkinen > > --- > > arch/x86/kernel/cpu/intel.c | 41 +++++++++++++++++++++++++++++++++++++ > > 1 file changed, 41 insertions(+) > > ... > > > @@ -761,6 +797,11 @@ static void init_intel(struct cpuinfo_x86 *c) > > if (cpu_has(c, X86_FEATURE_TME)) > > detect_tme(c); > > > > +#ifdef CONFIG_INTEL_SGX > > + if (cpu_has(c, X86_FEATURE_SGX)) > > + detect_sgx(c); > > +#endif > > You can remove the ifdeffery here and put the ifdef around the function > body and drop the __maybe_unused tag: OK, so I remember getting feedback on some unrelated to SGX stuff that I should use __maybe_unused in the past. That is why I used it here instead of ifdeffery. It is used in bunch of places in the kernel. I'm a bit confused when using it is a right thing and when it should be avoided. /Jarkko