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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,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 0DC97C3A5A1 for ; Thu, 22 Aug 2019 14:42:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id DA191233A1 for ; Thu, 22 Aug 2019 14:42:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730980AbfHVOmT (ORCPT ); Thu, 22 Aug 2019 10:42:19 -0400 Received: from mga09.intel.com ([134.134.136.24]:61592 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726332AbfHVOmT (ORCPT ); Thu, 22 Aug 2019 10:42:19 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 22 Aug 2019 07:42:18 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,417,1559545200"; d="scan'208";a="208190731" Received: from greathea-mobl2.ger.corp.intel.com ([10.252.39.37]) by fmsmga002.fm.intel.com with ESMTP; 22 Aug 2019 07:42:17 -0700 Message-ID: Subject: Re: [PATCH] x86/sgx: Return 0 when !CONFIG_INTEL_SGX_DRIVER From: Jarkko Sakkinen To: Sean Christopherson Cc: linux-sgx@vger.kernel.org Date: Thu, 22 Aug 2019 17:42:16 +0300 In-Reply-To: <20190822003122.GN29345@linux.intel.com> References: <20190714143212.971-1-jarkko.sakkinen@linux.intel.com> <20190715135902.GA442@linux.intel.com> <20190801162219.fqmkxlp4mgm4gi3f@linux.intel.com> <20190801162931.GB6783@linux.intel.com> <20190802193321.llx4dcqhslh46toy@linux.intel.com> <20190813012227.GJ4996@linux.intel.com> <20190815215600.u3cz27y27nrldq3i@linux.intel.com> <20190821172400.GH29345@linux.intel.com> <20190822002940.hb7xjbrdkxxx4zoe@linux.intel.com> <20190822003122.GN29345@linux.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.32.2-1 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 Wed, 2019-08-21 at 17:31 -0700, Sean Christopherson wrote: > On Thu, Aug 22, 2019 at 03:29:40AM +0300, Jarkko Sakkinen wrote: > > On Wed, Aug 21, 2019 at 10:24:00AM -0700, Sean Christopherson wrote: > > > How does the current code not align with this approach? The core subsystem > > > should tear itself down if loading the driver fails, which includes failing > > > because it doesn't exist. > > > > I get now the real issue that you are trying to point out (did not > > earlier). Still, I think your approach to fix it needs some > > reconsideration. > > > > Something that *does not exist* can never fail. That should be dead > > obvious. > > > > If the SGX driver does not exit and KVM does not have SGX support > > compiled in, then the only logical conclusion that you can end up with > > is that neither the SGX core should exist in vmlinux in the first place. > > > > This all summarizes to that I have to remove the INTEL_SGX_DRIVER > > kconfig flag. Its existence can only be considered when there >= 2 > > in-kernel users for SGX. > > That works too. It is only thing that fixes the issue. Leaving unused code to vmlinux can be classified as a regression. /Jarkko