Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752817AbcD2UFB (ORCPT ); Fri, 29 Apr 2016 16:05:01 -0400 Received: from mga01.intel.com ([192.55.52.88]:50576 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751710AbcD2UE7 (ORCPT ); Fri, 29 Apr 2016 16:04:59 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,553,1455004800"; d="scan'208";a="795280055" Date: Fri, 29 Apr 2016 23:04:49 +0300 From: Jarkko Sakkinen To: Jethro Beekman Cc: gregkh@linuxfoundation.org, "open list:STAGING SUBSYSTEM" , "maintainer:X86 ARCHITECTURE 32-BIT AND 64-BIT" , "open list:X86 ARCHITECTURE 32-BIT AND 64-BIT" , Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner Subject: Re: [PATCH 3/6] intel_sgx: driver for Intel Secure Guard eXtensions Message-ID: <20160429200449.GB27821@intel.com> References: <1461605698-12385-1-git-send-email-jarkko.sakkinen@linux.intel.com> <1461605698-12385-4-git-send-email-jarkko.sakkinen@linux.intel.com> <57206102.3050507@jbeekman.nl> <20160427124056.GA22003@intel.com> <57214C07.8090806@jbeekman.nl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <57214C07.8090806@jbeekman.nl> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1053 Lines: 26 On Wed, Apr 27, 2016 at 04:32:23PM -0700, Jethro Beekman wrote: > On 27-04-16 05:40, Jarkko Sakkinen wrote: > >> The hardware supports calling EEXTEND on only a part of a page, I think the > >> driver should also support that. > > > > Why would you want to do that? > > You might have segments in a binary that don't start at the beginning of a page > or that end before the end of a page. For example: > > Type Offset VirtAddr PhysAddr > FileSiz MemSiz Flags Align > LOAD 0x0000000000000000 0x0000000000000000 0x0000000000000000 > 0x000000000001bcac 0x000000000001bcac R E 1000 > LOAD 0x000000000001c8e8 0x000000000001c8e8 0x000000000001c8e8 > 0x0000000000000790 0x0000000000000c68 RW 1000 > > There's no need to measure the extra padding (0x1bd00--0x1c7ff and > 0x1cb00--0x1cfff) in this case. Do you see this as a performance issue or why do you think that this would hurt that much? > Jethro /Jarkko