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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT autolearn=ham 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 46B77C43334 for ; Tue, 4 Sep 2018 18:18:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 00B7B2075E for ; Tue, 4 Sep 2018 18:18:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 00B7B2075E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727752AbeIDWor (ORCPT ); Tue, 4 Sep 2018 18:44:47 -0400 Received: from mga05.intel.com ([192.55.52.43]:60916 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726507AbeIDWor (ORCPT ); Tue, 4 Sep 2018 18:44:47 -0400 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 04 Sep 2018 11:18:31 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.53,330,1531810800"; d="scan'208";a="260655353" Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.20]) by fmsmga006.fm.intel.com with ESMTP; 04 Sep 2018 11:17:35 -0700 Date: Tue, 4 Sep 2018 11:17:35 -0700 From: Sean Christopherson To: Andy Shevchenko Cc: Jarkko Sakkinen , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , Platform Driver , Dave Hansen , nhorman@redhat.com, npmccallum@redhat.com, linux-sgx@vger.kernel.org, serge.ayoun@intel.com, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , suresh.b.siddha@intel.com, Linux Kernel Mailing List Subject: Re: [PATCH v13 07/13] x86/sgx: Add data structures for tracking the EPC pages Message-ID: <20180904181735.GA5820@linux.intel.com> References: <20180827185507.17087-1-jarkko.sakkinen@linux.intel.com> <20180827185507.17087-8-jarkko.sakkinen@linux.intel.com> <20180904174914.GA5690@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Sep 04, 2018 at 09:01:15PM +0300, Andy Shevchenko wrote: > On Tue, Sep 4, 2018 a> +/** > > > > > + va = ioremap_cache(addr, size); > > > > + if (!va) > > > > + return -ENOMEM; > > > > > > I'm not sure this is a right API. Do we operate with memory? Does it > > > have I/O side effects? > > > If no, memremap() would be better to use. > > > > Preserving __iomem is desirable. There aren't side effects per se, > > but direct non-enclave accesses to the EPC get abort page semantics so > > the kernel shouldn't be directly dereferencing a pointer to the EPC. > > Though by that argument, sgx_epc_bank.va, sgx_epc_addr's return and > > all ENCLS helpers should be tagged __iomem. > > Why? > Does it related to *any* I/O? No, hence my other comment that __private or a new tag altogether may be more appropriate. The noderef attribute is what we truly care about.