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=-2.3 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 929DCC3A59E for ; Thu, 22 Aug 2019 00:31:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 6602D21848 for ; Thu, 22 Aug 2019 00:31:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728042AbfHVAbX (ORCPT ); Wed, 21 Aug 2019 20:31:23 -0400 Received: from mga03.intel.com ([134.134.136.65]:41433 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727291AbfHVAbX (ORCPT ); Wed, 21 Aug 2019 20:31:23 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Aug 2019 17:31:22 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,414,1559545200"; d="scan'208";a="169597197" Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.41]) by orsmga007.jf.intel.com with ESMTP; 21 Aug 2019 17:31:22 -0700 Date: Wed, 21 Aug 2019 17:31:22 -0700 From: Sean Christopherson To: Jarkko Sakkinen Cc: linux-sgx@vger.kernel.org Subject: Re: [PATCH] x86/sgx: Return 0 when !CONFIG_INTEL_SGX_DRIVER Message-ID: <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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190822002940.hb7xjbrdkxxx4zoe@linux.intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org 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.