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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 247C7C43144 for ; Mon, 25 Jun 2018 09:01:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C4D1325651 for ; Mon, 25 Jun 2018 09:01:21 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C4D1325651 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-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754647AbeFYJBU (ORCPT ); Mon, 25 Jun 2018 05:01:20 -0400 Received: from mga18.intel.com ([134.134.136.126]:47075 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754359AbeFYJBS (ORCPT ); Mon, 25 Jun 2018 05:01:18 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga106.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Jun 2018 02:01:17 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.51,269,1526367600"; d="scan'208";a="52013082" Received: from jsakkine-mobl1.tm.intel.com (HELO sfriis-mobl.ger.corp.intel.com) ([10.237.50.42]) by orsmga008.jf.intel.com with ESMTP; 25 Jun 2018 02:01:13 -0700 Message-ID: <2329657de3b24cd45db2ad4abaddf3d473da4fdf.camel@linux.intel.com> Subject: Re: [PATCH v11 09/13] x86, sgx: basic routines for enclave page cache From: Jarkko Sakkinen To: Dave Hansen Cc: x86@kernel.org, platform-driver-x86@vger.kernel.org, sean.j.christopherson@intel.com, nhorman@redhat.com, npmccallum@redhat.com, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , "open list:INTEL SGX" Date: Mon, 25 Jun 2018 12:01:12 +0300 In-Reply-To: <5226fbdc-dcad-4856-68bb-3219ab31b30d@intel.com> References: <20180608171216.26521-1-jarkko.sakkinen@linux.intel.com> <20180608171216.26521-10-jarkko.sakkinen@linux.intel.com> <3c1b04d6-6e93-efaa-1890-101b7fd9784c@intel.com> <20180619145753.GB8034@linux.intel.com> <5226fbdc-dcad-4856-68bb-3219ab31b30d@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.1-2 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2018-06-19 at 08:32 -0700, Dave Hansen wrote: > > For 32-bit (albeit not supported at this point) it makes sense to always > > use kmap_atomic_pfn() as the virtua address area is very limited. > > That makes no sense. 32-bit kernels have plenty of virtual address > space if not using highmem. AFAIK the vmalloc area is located in the last 128MB that and ioremap() of EPC would consume a big portion of that. > > KVM works only with writable MSRs. Driver works both with writable > > and read-only MSRs. > > Could you help with my confusion by documenting this a bit? Sure. /Jarkko