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=-7.3 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=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 6C473C433ED for ; Sun, 25 Apr 2021 15:12:17 +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 1B102610C8 for ; Sun, 25 Apr 2021 15:12:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1B102610C8 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=xen.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.117236.223047 (Exim 4.92) (envelope-from ) id 1lagQD-0007Lm-Bs; Sun, 25 Apr 2021 15:11:45 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 117236.223047; Sun, 25 Apr 2021 15:11:45 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lagQD-0007Lf-8q; Sun, 25 Apr 2021 15:11:45 +0000 Received: by outflank-mailman (input) for mailman id 117236; Sun, 25 Apr 2021 15:11:44 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lagQC-0007La-19 for xen-devel@lists.xenproject.org; Sun, 25 Apr 2021 15:11:44 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1lagQA-0003kz-9C; Sun, 25 Apr 2021 15:11:42 +0000 Received: from 54-240-197-239.amazon.com ([54.240.197.239] 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 1lagQA-0007Hi-2d; Sun, 25 Apr 2021 15:11:42 +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=7C6eqqB4u8svDNxQWrKNWGDuzYXTR3XnATeXIg04FiY=; b=xhyri9Shxt5jirzCtdBPoop/fC 1r7njQsj2OcZiWCiME8zT3ILppbsBugYNLiHad3nYUn7/dGHbqZaFqSpWtmtZ5G0VunExgbQfOvZd vTcgAdtumc+sutip7i1iUf9fKxdXvZPd4sBxjGMCONeJGBXxLljitVowjXXAExq0d0ac=; Subject: Re: [PATCH RFC 4/6] xen/arm: mm: Allow other mapping size in xen_pt_update_entry() To: Stefano Stabellini Cc: xen-devel@lists.xenproject.org, bertrand.marquis@arm.com, Julien Grall , Volodymyr Babchuk References: <20201119190751.22345-1-julien@xen.org> <20201119190751.22345-5-julien@xen.org> <1ba4afef-7efa-6d1a-5929-ec2652dbbb21@xen.org> From: Julien Grall Message-ID: <7aa25179-2926-d829-3fac-41aeda61dd4f@xen.org> Date: Sun, 25 Apr 2021 16:11:40 +0100 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:78.0) Gecko/20100101 Thunderbird/78.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Hi Stefano, On 30/11/2020 22:05, Stefano Stabellini wrote: > On Sat, 28 Nov 2020, Julien Grall wrote: >> If you take the ``if`` alone, yes they are alignment check. But if you take >> the overall code, then it will just compute which mapping size can be used. >> >> However, what I am disputing here is "rely" because there are no assumption >> made on the alignment in the loop (we are able to cater any size). In fact, >> the fact mfn and vfn should be aligned to the mapping size is a requirement >> from the hardware and not the implementation. > > OK, maybe the "rely" gives a bad impression. What about: > > This loop relies on mfn, vfn, and nr_mfn, to be all superpage aligned > (mfn and vfn have to be architecturally), and it uses `mask' to check > for that. > > Feel free to reword it differently if you have a better idea. I have used your new wording proposal. Cheers, -- Julien Grall