From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751486AbdKZSqc (ORCPT ); Sun, 26 Nov 2017 13:46:32 -0500 Received: from mga05.intel.com ([192.55.52.43]:25914 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751297AbdKZSqb (ORCPT ); Sun, 26 Nov 2017 13:46:31 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.44,460,1505804400"; d="scan'208";a="6328358" Date: Sun, 26 Nov 2017 20:46:27 +0200 From: Jarkko Sakkinen To: platform-driver-x86@vger.kernel.org, x86@kernel.org Cc: linux-kernel@vger.kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Darren Hart , Andy Shevchenko Subject: Re: [PATCH v6 06/11] intel_sgx: driver for Intel Software Guard Extensions Message-ID: <20171126184627.hegr3qzgous5ivpe@linux.intel.com> References: <20171125193132.24321-1-jarkko.sakkinen@linux.intel.com> <20171125193132.24321-7-jarkko.sakkinen@linux.intel.com> <20171126173356.ik7dhvvcojgermof@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20171126173356.ik7dhvvcojgermof@linux.intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Nov 26, 2017 at 07:33:56PM +0200, Jarkko Sakkinen wrote: > > +struct sgx_encl_page { > > + unsigned long addr; > > + unsigned int flags; > > + void *epc_page; > > + struct sgx_va_page *va_page; > > + unsigned int va_offset; > > + struct list_head list; > > +}; > > This can be without major streches hoops packed way more. There are 12 > bits free for use in the addr field. I can use low three bits for flags > and upper nine bits for va_offset. > > I think I can also quite easily union epc_page and va_page fields. > > With these changes the struct would shrink to: > > struct sgx_encl_page { > unsigned long addr; > union { > void *epc_page; > struct sgx_va_page *va_page; > }; > struct list_head list; > }; Once I started to thinking more about this I realized that this can be shrunk even further. I can drop the list field and use a tag for loaded pages in the radix tree where these are stored. The end result would be struct sgx_encl_page { unsigned long addr; union { void *epc_page; struct sgx_va_page *va_page; }; }; /Jarkko