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=-1.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS 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 65107C43387 for ; Mon, 17 Dec 2018 20:10:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3541B20874 for ; Mon, 17 Dec 2018 20:10:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1545077435; bh=ryMIVu4Zmu6P2F/2xwOzzWnMPWMEZsy0oZCxTdFnGgo=; h=References:In-Reply-To:From:Date:Subject:To:Cc:List-ID:From; b=qd+FOmZ4s8fVQJPHy34CqMRq04Tp1wVNKAn0qQ6jn19om7t0/HF9z64rUtpdf6iWT cKF42o5DqJ27b0bUwXH/OQOMf2+gwhAEa7C1Os5vcMYIty9XagPXAZbmEIMnLf0fF/ 84LVYU2ba8g6cXOpFBvXtA2ag3oOGSz1PyTVB7M8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388934AbeLQUKe (ORCPT ); Mon, 17 Dec 2018 15:10:34 -0500 Received: from mail.kernel.org ([198.145.29.99]:38736 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727038AbeLQUKd (ORCPT ); Mon, 17 Dec 2018 15:10:33 -0500 Received: from mail-wr1-f41.google.com (mail-wr1-f41.google.com [209.85.221.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 75AE1217D9 for ; Mon, 17 Dec 2018 20:10:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1545077432; bh=ryMIVu4Zmu6P2F/2xwOzzWnMPWMEZsy0oZCxTdFnGgo=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=145bLCptIzc+C9sMTwZRBpVURvke8dssVCj8KQ8aEWZbuUvx3Bsx2FW+JyiJFOZlc X9QNHUcsF91d79zlxBZpZq3hQVTycsgnRJ3K0Nn1Cb6c9Z37SKa777kQnlTvbrMbkI p92INpmopdHCsj0BnyGaFkhC3muLh/5PMoCoiEPk= Received: by mail-wr1-f41.google.com with SMTP id 96so13631349wrb.2 for ; Mon, 17 Dec 2018 12:10:32 -0800 (PST) X-Gm-Message-State: AA+aEWbtsJtwHgcQa2XMlOxGDoVMezeXml0MNZQJQ3wiNtX/oBY3XR2G 7U382nOqOBVQ6ivDfoMyWPQ6zd7m6KoPxV9ZzFNndg== X-Google-Smtp-Source: AFSGD/VM3edS6O8zz+RsOBb4JTUkevr2P5McfhitYh1Xo92EGS8IuoMZPSy3Ik31ENeUguBXU5lOAviZXYHYa7n6Az8= X-Received: by 2002:adf:e08c:: with SMTP id c12mr11214927wri.199.1545077428920; Mon, 17 Dec 2018 12:10:28 -0800 (PST) MIME-Version: 1.0 References: <20181116010412.23967-1-jarkko.sakkinen@linux.intel.com> <20181116010412.23967-19-jarkko.sakkinen@linux.intel.com> <7d5cde02-4649-546b-0f03-2d6414bb80b5@intel.com> <20181217180102.GA12560@linux.intel.com> <20181217183613.GD12491@linux.intel.com> <20181217184333.GA26920@linux.intel.com> <20181217194913.GD29785@linux.intel.com> <16fdd37a-b9cc-1045-1497-2cfff6af176a@intel.com> <826f6a5a-fdf6-e7e5-d2d8-bcdc57c016fe@intel.com> In-Reply-To: <826f6a5a-fdf6-e7e5-d2d8-bcdc57c016fe@intel.com> From: Andy Lutomirski Date: Mon, 17 Dec 2018 12:10:17 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v17 18/23] platform/x86: Intel SGX driver To: Dave Hansen Cc: Andy Lutomirski , Jarkko Sakkinen , Sean Christopherson , X86 ML , Platform Driver , linux-sgx@vger.kernel.org, nhorman@redhat.com, npmccallum@redhat.com, "Ayoun, Serge" , shay.katz-zamir@intel.com, Haitao Huang , Andy Shevchenko , Thomas Gleixner , "Svahn, Kai" , mark.shanahan@intel.com, Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Darren Hart , Andy Shevchenko , "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)" Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 17, 2018 at 12:03 PM Dave Hansen wrote: > > On 12/17/18 11:55 AM, Andy Lutomirski wrote: > >> You're effectively rebuilding reverse-mapping infrastructure here. It's > >> a frequent thing for the core VM to need to go from 'struct page' back > >> to the page tables mapping it. For that we go (logically) > >> page->{anon_vma,mapping}->vma->vm_mm->pagetable. > > This is a bit outside my expertise here, but doesn't > > unmap_mapping_range() do exactly what SGX wants? > > There's no 'struct page' for enclave memory as it stands. That means no > page cache, and that means there's no 'struct address_space *mapping' in > the first place. > > Basically, the choice was made a long time ago to have SGX's memory > management live outside the core VM. I've waffled back and forth on it, > but I do still think this is the right way to do it. AFAICS a lack of struct page isn't a problem. The core code seems to understand that address_space objects might cover non-struct-page memory. Morally, enclave memory is a lot like hot-unpluggable PCI space.