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=-5.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,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 0BEABC4727C for ; Wed, 30 Sep 2020 14:33:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BE04B2076B for ; Wed, 30 Sep 2020 14:33:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729903AbgI3Odl (ORCPT ); Wed, 30 Sep 2020 10:33:41 -0400 Received: from mga14.intel.com ([192.55.52.115]:12111 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728149AbgI3Odl (ORCPT ); Wed, 30 Sep 2020 10:33:41 -0400 IronPort-SDR: uucD7iNZfUD437qQdWVZ0ByF0k1KoBuhLPhuqU9eeEz0cAPJxOIvKUnQUFaReSZTsnfKFEJQuk QOF3Nj979pEQ== X-IronPort-AV: E=McAfee;i="6000,8403,9759"; a="161681683" X-IronPort-AV: E=Sophos;i="5.77,322,1596524400"; d="scan'208";a="161681683" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Sep 2020 07:33:40 -0700 IronPort-SDR: zJnv60FukiLQHUkGiqT+JPjQT3mWbyD31s6FGUDb3+RCiLbPH20IkEOmxO9DTbWnAuUgbJea1Y vFgd4jgxD9Ag== X-IronPort-AV: E=Sophos;i="5.77,322,1596524400"; d="scan'208";a="308177497" Received: from mdioury-mobl.amr.corp.intel.com (HELO [10.213.184.164]) ([10.213.184.164]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Sep 2020 07:33:39 -0700 Subject: Re: [PATCH] x86/vdso: Remove retpoline from SGX vDSO call To: Jarkko Sakkinen Cc: linux-sgx@vger.kernel.org, x86@kernel.org, Haitao Huang , Sean Christopherson , Andrew Cooper , Borislav Petkov , Dave Hansen , Andy Lutomirski , Cedric Xing References: <20200930140108.48075-1-jarkko.sakkinen@linux.intel.com> <92578646-83a4-606c-b251-4d80cb62399c@intel.com> <20200930142017.GA49393@linux.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: <20200930142017.GA49393@linux.intel.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On 9/30/20 7:20 AM, Jarkko Sakkinen wrote: > I'm not expert on Spectre, or any sort of security researcher, but I've > read a few papers about and understand the general concept. With the > constraints how the callback is used in practice, I'd *guess* it is > fine to drop retpoline but I really need some feedback on this from > people who understand these attacks better. Do you recall why you added it in the first place? What was the motivation for it? Were you responding to a review comment?