Received: by 2002:a25:868d:0:0:0:0:0 with SMTP id z13csp2817409ybk; Mon, 18 May 2020 08:37:00 -0700 (PDT) X-Google-Smtp-Source: ABdhPJwg1YbhVYoleczMt1qBTmT69ujY81A9F01iYHgKgCy79imy/1GZ5v60rnrBNzh0gzkTCV4y X-Received: by 2002:a17:906:dbc9:: with SMTP id yc9mr15548460ejb.157.1589816220082; Mon, 18 May 2020 08:37:00 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1589816220; cv=none; d=google.com; s=arc-20160816; b=e0LHaE8+XMAK2gn1zg1ppZ2oDglgKRmzY0+DBqZCD5taGuQsVMm7n6QNizRJF/sP/O RdEwRBlgDmNMzHxF5Tsf4tEaNQOA4XNp/ah7+KHUylvqgH5ARBe6GwDTFFdtPZAoUGUR H7aUiqCh4V9DzBON0RIl93EVHyY2chBqAB+yQ2I74Ne45T2BKlxxgTGTBm1Oh7uJBP6o JNnCJ6YLgIuYbhNnOG7cyuVl7ahUj/yyB4CVYxgrZmovx7y/JhM70aZLJLQDySdWukqN e/zriKsvW+xmGvu+ZyS+qCM3yU2LoNmRkIiCaC2aEFKDtd/xKjpoFi9kskEcofHfqhYY BN+A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:in-reply-to:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :ironport-sdr:ironport-sdr; bh=Kz1DiB0A8n7qvUoTQCw2qjFfIJIvDuwfD6zKJEy/hJU=; b=mQwc/f5gieLdjs/iyMJsXl/JmqfE0I6wAk6Y04iFz4fSuTzlPqrteXGqjqTllxaZXB kNB8titL0h70Cy3nvkzuGN+c9aYqWdZyV3laeQEx+7flFSZV62YhY0gcQu8Chfy4QIhR 5+vT8AfHCX90LSd9xwyMdIzQi8wVZXnP5UqlcLF3Bo6ARMNj3jbcOxjOQXOdI/NJhAms 4pOeAq9io1yOxoyeTXzkm/9eeAbDrkCCMM61RgfKQvP+n9vBupVUJhc3LZOWEIRjzBFn e/KYdMd2sKPWRbvgxz1NFfRIUCDscVpGo57/QiTtx9KEbWfmDPMqoixfSwTvftoilXMO B1CA== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id b18si6586926edr.76.2020.05.18.08.36.36; Mon, 18 May 2020 08:37:00 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=intel.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728361AbgERPeM (ORCPT + 99 others); Mon, 18 May 2020 11:34:12 -0400 Received: from mga14.intel.com ([192.55.52.115]:42695 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728298AbgERPeJ (ORCPT ); Mon, 18 May 2020 11:34:09 -0400 IronPort-SDR: OXeartJWH0bxtj2gH0kMkmvq0tVe6Qz+RjzMQIAdHymNJmSpreNWwbSw5jA8rsWnC2DsbxWmH7 V5vAYg1xbRJg== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 May 2020 08:34:08 -0700 IronPort-SDR: eV5C3H+cnoC0A8uX4kOxBmXf/PSL+93BTzOl8w2BmzU4Y5t+/ija7Mo2k1ocUFqS2o5A3HnkRd YpxgeX4S3jxg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,407,1583222400"; d="scan'208";a="465617760" Received: from tassilo.jf.intel.com (HELO tassilo.localdomain) ([10.7.201.21]) by fmsmga005.fm.intel.com with ESMTP; 18 May 2020 08:34:08 -0700 Received: by tassilo.localdomain (Postfix, from userid 1000) id D3CA8301B7F; Mon, 18 May 2020 08:34:07 -0700 (PDT) Date: Mon, 18 May 2020 08:34:07 -0700 From: Andi Kleen To: Jarkko Sakkinen Cc: Sasha Levin , linux-kernel@vger.kernel.org, tglx@linutronix.de, bp@alien8.de, luto@kernel.org, hpa@zytor.com, dave.hansen@intel.com, tony.luck@intel.com, ravi.v.shankar@intel.com, chang.seok.bae@intel.com Subject: Re: [PATCH v12 00/18] Enable FSGSBASE instructions Message-ID: <20200518153407.GA499505@tassilo.jf.intel.com> References: <20200511045311.4785-1-sashal@kernel.org> <0186c22a8a6be1516df0703c421faaa581041774.camel@linux.intel.com> <20200515164013.GF29995@sasha-vm> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Yes, for SGX this is functional feature because enclave entry points, > thread control structures (aka TCS's), reset FSBASE and GSBASE registers > to fixed (albeit user defined) values. And syscall's can be done only > outside of enclave. > > This is a required feature for fancier runtimes (such as Graphene). Can you please explain a bit more? What do they need GS for? -Andi