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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 0D245C54FCF for ; Wed, 25 Mar 2020 15:01:25 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id D3D1920714 for ; Wed, 25 Mar 2020 15:01:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D3D1920714 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1jH7Wa-0002v3-L4; Wed, 25 Mar 2020 15:00:56 +0000 Received: from all-amaz-eas1.inumbo.com ([34.197.232.57] helo=us1-amaz-eas2.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1jH7WZ-0002uy-HK for xen-devel@lists.xenproject.org; Wed, 25 Mar 2020 15:00:55 +0000 X-Inumbo-ID: 6cbb932c-6ea9-11ea-8635-12813bfff9fa Received: from mx2.suse.de (unknown [195.135.220.15]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id 6cbb932c-6ea9-11ea-8635-12813bfff9fa; Wed, 25 Mar 2020 15:00:54 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx2.suse.de (Postfix) with ESMTP id A958FAD06; Wed, 25 Mar 2020 15:00:53 +0000 (UTC) To: julien@xen.org References: <20200322161418.31606-1-julien@xen.org> <20200322161418.31606-4-julien@xen.org> From: Jan Beulich Message-ID: <80c98b3e-efa7-66e6-bd47-61bc0560f535@suse.com> Date: Wed, 25 Mar 2020 16:00:48 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200322161418.31606-4-julien@xen.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [Xen-devel] [PATCH 03/17] xen/mm: Move the MM types in a separate header X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Stefano Stabellini , Wei Liu , Andrew Cooper , Julien Grall , Ian Jackson , George Dunlap , xen-devel@lists.xenproject.org Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" On 22.03.2020 17:14, julien@xen.org wrote: > From: Julien Grall > > It is getting incredibly difficult to use typesafe GFN/MFN/PFN in the > headers because of circular dependency. For instance, asm-x86/page.h > cannot include xen/mm.h. > > In order to convert more code to use typesafe, the types are now moved > in a separate header that requires only a few dependencies. We definitely need to do this, so thanks for investing the time. I think though that we want to settle up front (and perhaps record in a comment in the new header) what is or is not suitable to go into the new header. After all you're moving not just type definitions, but also simple helper functions. > --- a/xen/include/xen/mm.h > +++ b/xen/include/xen/mm.h > @@ -1,50 +1,7 @@ > /****************************************************************************** > * include/xen/mm.h > * > - * Definitions for memory pages, frame numbers, addresses, allocations, etc. > - * > * Copyright (c) 2002-2006, K A Fraser > - * > - * +---------------------+ > - * Xen Memory Management > - * +---------------------+ > - * > - * Xen has to handle many different address spaces. It is important not to > - * get these spaces mixed up. The following is a consistent terminology which > - * should be adhered to. > - * > - * mfn: Machine Frame Number > - * The values Xen puts into its own pagetables. This is the host physical > - * memory address space with RAM, MMIO etc. > - * > - * gfn: Guest Frame Number > - * The values a guest puts in its own pagetables. For an auto-translated > - * guest (hardware assisted with 2nd stage translation, or shadowed), gfn != > - * mfn. For a non-translated guest which is aware of Xen, gfn == mfn. > - * > - * pfn: Pseudophysical Frame Number > - * A linear idea of a guest physical address space. For an auto-translated > - * guest, pfn == gfn while for a non-translated guest, pfn != gfn. > - * > - * dfn: Device DMA Frame Number (definitions in include/xen/iommu.h) > - * The linear frame numbers of device DMA address space. All initiators for > - * (i.e. all devices assigned to) a guest share a single DMA address space > - * and, by default, Xen will ensure dfn == pfn. > - * > - * WARNING: Some of these terms have changed over time while others have been > - * used inconsistently, meaning that a lot of existing code does not match the > - * definitions above. New code should use these terms as described here, and > - * over time older code should be corrected to be consistent. > - * > - * An incomplete list of larger work area: > - * - Phase out the use of 'pfn' from the x86 pagetable code. Callers should > - * know explicitly whether they are talking about mfns or gfns. > - * - Phase out the use of 'pfn' from the ARM mm code. A cursory glance > - * suggests that 'mfn' and 'pfn' are currently used interchangeably, where > - * 'mfn' is the appropriate term to use. > - * - Phase out the use of gpfn/gmfn where pfn/mfn are meant. This excludes > - * the x86 shadow code, which uses gmfn/smfn pairs with different, > - * documented, meanings. > */ > > #ifndef __XEN_MM_H__ > @@ -54,100 +11,11 @@ > #include > #include > #include > -#include > #include > +#include Is there anything left in the header here which requires the explicit inclusion of xen/kernel.h? Jan