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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id B1E17C433EF for ; Fri, 24 Jun 2022 19:25:54 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.355853.583783 (Exim 4.92) (envelope-from ) id 1o4ovx-000601-OV; Fri, 24 Jun 2022 19:25:37 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 355853.583783; Fri, 24 Jun 2022 19:25:37 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1o4ovx-0005zu-Lr; Fri, 24 Jun 2022 19:25:37 +0000 Received: by outflank-mailman (input) for mailman id 355853; Fri, 24 Jun 2022 19:25:36 +0000 Received: from mail.xenproject.org ([104.130.215.37]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1o4ovw-0005zo-92 for xen-devel@lists.xenproject.org; Fri, 24 Jun 2022 19:25:36 +0000 Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1o4ovv-00065i-Tt; Fri, 24 Jun 2022 19:25:35 +0000 Received: from 54-240-197-238.amazon.com ([54.240.197.238] helo=[192.168.4.76]) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1o4ovv-0000Xr-La; Fri, 24 Jun 2022 19:25:35 +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:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID; bh=rPiSki+h44CFmX+VOegY1CamI283Ny0AJ7r0k2dZW5c=; b=6KNGtnpZtljpOp5AvZiWZfH9w9 GS9WW2IPfpXTUNEi3Raz8kqtyqkFyzofLjJQb3vww2xapTT744dvNcOpOWOvWnfroQdbn1SGjG6Xc ZAeiPEcGxc5PIja9i9Ost2tj1Z3LIQUvfT3VgNemzDFQ6ZXNqEgu5tGUeIIJRMpsIewc=; Message-ID: Date: Fri, 24 Jun 2022 20:25:33 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Subject: Re: [PATCH v5 1/8] xen/arm: introduce static shared memory To: Penny Zheng , xen-devel@lists.xenproject.org Cc: wei.chen@arm.com, Stefano Stabellini , Bertrand Marquis , Volodymyr Babchuk References: <20220620051114.210118-1-Penny.Zheng@arm.com> <20220620051114.210118-2-Penny.Zheng@arm.com> From: Julien Grall In-Reply-To: <20220620051114.210118-2-Penny.Zheng@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Hi Penny, I have looked at the code and I have further questions about the binding. On 20/06/2022 06:11, Penny Zheng wrote: > --- > docs/misc/arm/device-tree/booting.txt | 120 ++++++++++++++++++++++++++ > xen/arch/arm/Kconfig | 6 ++ > xen/arch/arm/bootfdt.c | 68 +++++++++++++++ > xen/arch/arm/include/asm/setup.h | 3 + > 4 files changed, 197 insertions(+) > > diff --git a/docs/misc/arm/device-tree/booting.txt b/docs/misc/arm/device-tree/booting.txt > index 98253414b8..6467bc5a28 100644 > --- a/docs/misc/arm/device-tree/booting.txt > +++ b/docs/misc/arm/device-tree/booting.txt > @@ -378,3 +378,123 @@ device-tree: > > This will reserve a 512MB region starting at the host physical address > 0x30000000 to be exclusively used by DomU1. > + > +Static Shared Memory > +==================== > + > +The static shared memory device tree nodes allow users to statically set up > +shared memory on dom0less system, enabling domains to do shm-based > +communication. > + > +- compatible > + > + "xen,domain-shared-memory-v1" > + > +- xen,shm-id > + > + An 8-bit integer that represents the unique identifier of the shared memory > + region. The maximum identifier shall be "xen,shm-id = <0xff>". There is nothing in Xen that will ensure that xen,shm-id will match for all the nodes using the same region. I see you write it to the guest device-tree. However there is a mismatch of the type: here you use an integer whereas the guest binding is using a string. Cheers, -- Julien Grall