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=-8.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 22E4CC433EF for ; Fri, 17 Sep 2021 15:53:14 +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 D251D611C8 for ; Fri, 17 Sep 2021 15:53:13 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org D251D611C8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xen.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.189541.339318 (Exim 4.92) (envelope-from ) id 1mRGAh-0003Th-5h; Fri, 17 Sep 2021 15:53:03 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 189541.339318; Fri, 17 Sep 2021 15:53:03 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mRGAh-0003Ta-1f; Fri, 17 Sep 2021 15:53:03 +0000 Received: by outflank-mailman (input) for mailman id 189541; Fri, 17 Sep 2021 15:53:01 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mRGAf-0003TU-KF for xen-devel@lists.xenproject.org; Fri, 17 Sep 2021 15:53:01 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mRGAd-0001Qu-L7; Fri, 17 Sep 2021 15:52:59 +0000 Received: from [202.153.84.92] (helo=a483e7b01a66.ant.amazon.com) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1mRGAd-0003Sx-Ah; Fri, 17 Sep 2021 15:52:59 +0000 X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Content-Transfer-Encoding:Content-Type:In-Reply-To: MIME-Version:Date:Message-ID:From:References:Cc:To:Subject; bh=0xA5ARbzT7zqy34RdeBkN5rAk75b7CzxrS79b8ftDgo=; b=PRNtL20ZUluTHgwrsQQ11JAvGa nGzq1hfgmbYmsGmcFZk4uZbYFOkMx3Wm2T30Wl8cznV19oSiYnALRCyCnNbAxo/KUt/hnzIcbuZkC oL6yTyu538eiVTZIkyjmsAX51Pj45aObMfT0y78g+VaCzsEPf3dSJ34mBJPXs+ybB9io=; Subject: Re: [PATCH V2 2/3] xen/arm: Add handling of extended regions for Dom0 To: Oleksandr , Stefano Stabellini Cc: xen-devel@lists.xenproject.org, Oleksandr Tyshchenko , Volodymyr Babchuk , Henry Wang , Bertrand Marquis , Wei Chen References: <1631297924-8658-1-git-send-email-olekstysh@gmail.com> <1631297924-8658-3-git-send-email-olekstysh@gmail.com> From: Julien Grall Message-ID: Date: Fri, 17 Sep 2021 20:52:52 +0500 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit On 16/09/2021 00:10, Oleksandr wrote: >>> + * The extended regions will be prevalidated by the memory hotplug path >>> + * in Linux which requires for any added address range to be within >>> maximum >>> + * possible addressable physical memory range for which the linear >>> mapping >>> + * could be created. >>> + * For 48-bit VA space size the maximum addressable range are: >>> + * 0x40000000 - 0x80003fffffff >> Please don't make Linux-specific comments in Xen code for interfaces >> that are supposed to be OS-agnostic. > > You are right. I just wanted to describe where these magic numbers come > from. > Someone might question why, for example, "0 ... max_gpaddr" can't be > used. I will move > that Linux-specific comments to the commit message to keep some > justification of these numbers. Please keep some rationale in the code. This is a lot easier to understand the code without having to play the git blame game. Cheers, -- Julien Grall