From patchwork Tue Sep 7 06:52:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Luca Fancellu X-Patchwork-Id: 12477621 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 CE2DBC433F5 for ; Tue, 7 Sep 2021 06:52:57 +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 91EAA610FF for ; Tue, 7 Sep 2021 06:52:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 91EAA610FF Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.xenproject.org Received: from list by lists.xenproject.org with outflank-mailman.180441.327105 (Exim 4.92) (envelope-from ) id 1mNUyI-0002YK-H5; Tue, 07 Sep 2021 06:52:42 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 180441.327105; Tue, 07 Sep 2021 06:52:42 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1mNUyI-0002YD-Do; Tue, 07 Sep 2021 06:52:42 +0000 Received: by outflank-mailman (input) for mailman id 180441; Tue, 07 Sep 2021 06:52:41 +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 4.92) (envelope-from ) id 1mNUyH-0002Y7-F7 for xen-devel@lists.xenproject.org; Tue, 07 Sep 2021 06:52:41 +0000 Received: from foss.arm.com (unknown [217.140.110.172]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTP id 31791194-0fa8-11ec-b0d7-12813bfff9fa; Tue, 07 Sep 2021 06:52:40 +0000 (UTC) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B06AF31B; Mon, 6 Sep 2021 23:52:39 -0700 (PDT) Received: from e125770.cambridge.arm.com (e125770.cambridge.arm.com [10.1.197.16]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 5DA4C3F5A1; Mon, 6 Sep 2021 23:52:38 -0700 (PDT) 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" X-Inumbo-ID: 31791194-0fa8-11ec-b0d7-12813bfff9fa From: Luca Fancellu To: xen-devel@lists.xenproject.org Cc: bertrand.marquis@arm.com, wei.chen@arm.com, Andrew Cooper , George Dunlap , Ian Jackson , Jan Beulich , Julien Grall , Stefano Stabellini , Wei Liu Subject: [RFC PATCH] xen/design: Add design for EFI dom0less system start Date: Tue, 7 Sep 2021 07:52:28 +0100 Message-Id: <20210907065228.21794-1-luca.fancellu@arm.com> X-Mailer: git-send-email 2.17.1 Add a design describing a proposal to improve the EFI configuration file, adding keywords to describe domU guests and allowing to start a dom0less system. Signed-off-by: Luca Fancellu --- docs/designs/efi-arm-dom0less.md | 105 +++++++++++++++++++++++++++++++ 1 file changed, 105 insertions(+) create mode 100644 docs/designs/efi-arm-dom0less.md diff --git a/docs/designs/efi-arm-dom0less.md b/docs/designs/efi-arm-dom0less.md new file mode 100644 index 0000000000..8d8fa2243f --- /dev/null +++ b/docs/designs/efi-arm-dom0less.md @@ -0,0 +1,105 @@ +# Xen EFI configuration file + +The current configuration file used by Xen when it is started as an EFI +application is considering only the dom0 guest and doesn't have any +property to describe and load in memory domU guests. +Hence currently it's impossible to start a dom0less system using EFI. + +# Objective + +This document describes the proposed improvement to the Xen EFI +configuration file to list properly both the dom0 guest and the domU +guests as well. +The final goal is to be able to start a dom0less system using EFI. + +# Current Xen EFI configuration file + +The current configuration file is described by the documentation page +https://xenbits.xenproject.org/docs/unstable/misc/efi.html. + +Here an example: + +``` +[global] +default=section1 + +[section1] +options=console=vga,com1 com1=57600 loglvl=all noreboot +kernel=vmlinuz-3.0.31-0.4-xen [domain 0 command line options] +ramdisk=initrd-3.0.31-0.4-xen +xsm= +dtb=devtree.dtb +``` + +# Proposed improvement + +The proposed improvement to the current configuration file is the +introduction of new keywords to describe additional domUs. + +Here follows the proposed new keywords: + - domu#_kernel= [domU command line options] + - Mandatory kernel file for the domU# + - domu#_ramdisk= + - Optional ramdisk file for the domU# + - domu#_dtb= + - Optional dtb fragment file for the domU#, it is used for device + assignment (passthrough). + - domu#_property=cpus=2 + - Properties that should be added to the dtb in the domU node to + properly describe the domU guest. Refer to the documentation: + https://xenbits.xenproject.org/docs/unstable/misc/arm/device-tree/booting.txt, + section "Creating Multiple Domains directly from Xen". + +For all the keywords above, the # is a number that uniquely identifies +the guest. +The keywords domu#_kernel, domu#_ramdisk, domu#_dtb are unique, therefore there +must not be specified the same keyword twice in a section. +The # number is not enforcing any domid, it is just used to link each property +to the right guest, so there can be domu1_* guests that are started with domid 2 +and so on. + +The domu#_property can appear multiple times and it specifies an additional +property to be listed in the domU node inside the device tree, Xen will +not check if the same content is specified multiple times. + +There are some property whose name starts with an hash symbol (#address-cells, +#size-cells), in this case the line will be considered as a comment, so to +specify them, they have to be listed without the hash symbol, the documentation +will be updated as well to see the implemented handling of these special +properties. + +# Example of a configuration file describing a dom0less system + +The following configuration file is describing a dom0less system starting two +guests. + +``` +[global] +default=xen + +[xen] +# Xen boot arguments +options=noreboot console=dtuart dtuart=serial0 bootscrub=0 +# Xen device tree +dtb=devtree.dtb + +# Guest 1 +domu1_property=address-cells=2 +domu1_property=size-cells=2 +domu1_kernel=Image-domu1.bin console=ttyAMA0 root=/dev/ram0 rw +domu1_property=cpus=1 +domu1_property=memory=0xC0000 +domu1_dtb=domu.dtb + +# Guest 2 +domu2_kernel=Image-domu2.bin console=ttyAMA0 root=/dev/ram0 rw +domu2_property=cpus=2 +domu2_property=memory=0x100000 +domu2_property=vpl011 +``` + +In this example the Guest 1 is loading Image-domu1.bin as kernel and it is using +the passed boot arguments, it is also loading a device tree snippet for device +passthrough. +The second guest, Guest 2, is using another kernel and it will use the vpl011 +device.