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=-5.3 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_NONE,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 BDD47C433E0 for ; Thu, 21 Jan 2021 03:52:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 759892071C for ; Thu, 21 Jan 2021 03:52:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727258AbhAUDw3 (ORCPT ); Wed, 20 Jan 2021 22:52:29 -0500 Received: from mga02.intel.com ([134.134.136.20]:1575 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391032AbhATXv0 (ORCPT ); Wed, 20 Jan 2021 18:51:26 -0500 IronPort-SDR: Lk7qhQkgsH8kZuMPTLJ+dP7h0Z/ZT4tAAcwaUl6frA0p4DQsNDZV4UvRXhYdHGpOysIsPNLd3y MvFxf9hZGbfg== X-IronPort-AV: E=McAfee;i="6000,8403,9870"; a="166290433" X-IronPort-AV: E=Sophos;i="5.79,362,1602572400"; d="scan'208";a="166290433" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Jan 2021 15:50:34 -0800 IronPort-SDR: g4M/RD/FH8KyPXZxkbV0zW6eFF14063QepWWPH1Q2jCP2kOUhrTkcusenyJ4q3nYiPq8sc7pkN GbvacdqUznig== X-IronPort-AV: E=Sophos;i="5.79,362,1602572400"; d="scan'208";a="351266741" Received: from raavalos-mobl2.amr.corp.intel.com (HELO [10.212.38.24]) ([10.212.38.24]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Jan 2021 15:50:33 -0800 Subject: Re: [RFC PATCH v2 12/26] x86/sgx: Add helper to update SGX_LEPUBKEYHASHn MSRs To: Kai Huang Cc: Jarkko Sakkinen , linux-sgx@vger.kernel.org, kvm@vger.kernel.org, x86@kernel.org, seanjc@google.com, luto@kernel.org, haitao.huang@intel.com, pbonzini@redhat.com, bp@alien8.de, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com References: <5116fdc732e8e14b3378c44e3b461a43f330ed0c.1610935432.git.kai.huang@intel.com> <8613b3f1-c4f6-3e5d-4406-9476727666a7@intel.com> <20210121123625.c45deeccc690138f2417bd41@intel.com> From: Dave Hansen Autocrypt: addr=dave.hansen@intel.com; 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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210121123625.c45deeccc690138f2417bd41@intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On 1/20/21 3:36 PM, Kai Huang wrote: > I actually feel the function name already explains what the function does > clearly, therefore I don't think even comment is needed. To be honest I > don't know how to rephrase here. Perhaps: > > /* Update SGX LEPUBKEYHASH MSRs of the platform. */ Whee! I'm gonna write me a function comment! /* * A Launch Enclave (LE) must be signed with a public key * that matches this SHA256 hash. Usually overwrites Intel's * default signing key. */ So, this isn't a one-liner. *But*, it tells us what "le" means, what "pubkey" means and implies that there need to be 4x64-bits worth of MSR writes to get to a SHA256 hash. It also tells what it's usually doing here: overwriting Intel's blasted hash. It sure beats the entirely uncommented for loop that we've got today.