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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=unavailable 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 C1EF3ECDE47 for ; Thu, 8 Nov 2018 14:46:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 93C1F2081D for ; Thu, 8 Nov 2018 14:46:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 93C1F2081D Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-sgx-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727071AbeKIAWT (ORCPT ); Thu, 8 Nov 2018 19:22:19 -0500 Received: from mga09.intel.com ([134.134.136.24]:26519 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726847AbeKIAWT (ORCPT ); Thu, 8 Nov 2018 19:22:19 -0500 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 08 Nov 2018 06:46:13 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,480,1534834800"; d="scan'208";a="272425237" Received: from ibanaga-mobl1.ger.corp.intel.com (HELO localhost) ([10.249.254.75]) by orsmga005.jf.intel.com with ESMTP; 08 Nov 2018 06:46:04 -0800 Date: Thu, 8 Nov 2018 16:46:03 +0200 From: Jarkko Sakkinen To: Sean Christopherson Cc: x86@kernel.org, platform-driver-x86@vger.kernel.org, linux-sgx@vger.kernel.org, dave.hansen@intel.com, nhorman@redhat.com, npmccallum@redhat.com, serge.ayoun@intel.com, shay.katz-zamir@intel.com, haitao.huang@intel.com, andriy.shevchenko@linux.intel.com, tglx@linutronix.de, kai.svahn@intel.com, Suresh Siddha , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Darren Hart , Andy Shevchenko , "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" Subject: Re: [PATCH v16 18/22] platform/x86: Intel SGX driver Message-ID: <20181108144603.GA14072@linux.intel.com> References: <20181106134758.10572-1-jarkko.sakkinen@linux.intel.com> <20181106134758.10572-19-jarkko.sakkinen@linux.intel.com> <1541522400.7839.48.camel@intel.com> <20181107163757.GB11509@linux.intel.com> <20181107180057.GB24807@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181107180057.GB24807@linux.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org On Wed, Nov 07, 2018 at 10:00:57AM -0800, Sean Christopherson wrote: > What do we gain by a single buffer vs. separate buffers? The ioctl() > would be slightly smaller but it seems like the actual code would be > more complex. I'm fine with either. It was just a suggestion. > The enclave build process also utilizes the backing as temp storage > to avoid having to alloc kernel memory when queueing pages to be added > by the worker thread (which reminds me that I wanted to document why a > worker thread is used). Keeping this behavior would effectively make > providing backing mandatory. Would it be a problem just allocate those pages with alloc_page() and free them in the worker thread? > Are there any potential complications with ENCLS consuming userspace > pointers? We'd have to wrap them with user_access_{begin,end}() and > probably tweak the fixup, but I assume having the fixup handler means > we're generally ok? Last time I did it I used get_user_pages() for pinning. I'm not sure why I should do anything but just re-use that. /Jarkko