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=-7.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 8981FC433E3 for ; Thu, 23 Jul 2020 17:05:45 +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 4B03C20674 for ; Thu, 23 Jul 2020 17:05:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=xen.org header.i=@xen.org header.b="or8ZfDVK" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4B03C20674 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 localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jyeeQ-0006Lb-J4; Thu, 23 Jul 2020 17:04:58 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jyeeO-0006LW-MG for xen-devel@lists.xenproject.org; Thu, 23 Jul 2020 17:04:56 +0000 X-Inumbo-ID: a0e1fb95-cd06-11ea-8757-bc764e2007e4 Received: from mail.xenproject.org (unknown [104.130.215.37]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id a0e1fb95-cd06-11ea-8757-bc764e2007e4; Thu, 23 Jul 2020 17:04:55 +0000 (UTC) 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:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=Syxb0daW+OdrF+nQx4GmiQbu7VPA+Q5+5LZXAAjPSpg=; b=or8ZfDVK06yjVX+JhvGS0z+743 h1FcKRAltDcyD1bUK0KoDK2/7G5JWZiWVQ1wX6JPU4yrQSY35Z/ZNpsLV6MdFvU3Mb2RpL5fyGXih dbETLVapFegPSZzMdZDqHO+OX3YSJXL23FIAsyVoK3Wt8Ex+CZNlayNvW2F1H4JqBJsw=; Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1jyeeN-00055n-Cr; Thu, 23 Jul 2020 17:04:55 +0000 Received: from 54-240-197-238.amazon.com ([54.240.197.238] 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 1jyeeN-00014A-59; Thu, 23 Jul 2020 17:04:55 +0000 Subject: Re: Porting Xen to Jetson Nano To: Christopher Clark , Srinivas Bangalore References: <002801d66051$90fe2300$b2fa6900$@yujala.com> From: Julien Grall Message-ID: Date: Thu, 23 Jul 2020 18:04:53 +0100 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 8bit X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: xen-devel Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" Hi, On 23/07/2020 05:26, Christopher Clark wrote: > On Wed, Jul 22, 2020 at 10:59 AM Srinivas Bangalore wrote: >> Dear Xen experts, >> >> Would greatly appreciate some hints on how to move forward with this one… > > Hi Srini, > > I don't have any strong recommendations for you, but I do want to say > that I'm very happy to see you taking this project on and I am hoping > for your success. I have a newly-arrived Jetson Nano sitting on my > desk here, purchased with the intention of getting Xen up and running > on it, that I just haven't got to work on yet. I'm also familiar with > Chris Patterson, Kyle Temkin and Ian Campbell's previous Tegra Jetson > patches and it would be great to see some further progress made from > those. I agree that it would be good to have the support in upstream! > > In my recent experience with the Raspberry Pi 4, one basic observation > with ARM kernel bringup is that if your device tree isn't good, your > dom0 kernel can be missing the configuration it needs to use the > serial port correctly and you don't get any diagnostics from it after > Xen attempts to launch it, so I would just patch the right serial port > config directly into your Linux kernel (eg. hardcode specific things > onto the kernel command line) so you're not messing about with that > any more. > > The other thing I would recommend is patching in some printks into the > earliest part of the Xen parts of the Dom0 Linux kernel start code. > Others who are more familar with Xen on ARM may have some better > recommendations, but linux/arch/arm/xen/enlighten.c has a function > xen_guest_init that looks like a good place to stuff some extra > printks for some early proof-of-entry from your kernel, and that way > you'll have some indication whether execution has actually commenced > in there. Linux provides earlyprintk facilities that can be used in Xen. To enable it, you need to have your kernel built with CONFIG_EARLY_PRINTK=y and CONFIG_XEN=y. This can then be enabled by passing earlyprintk=xenboot on your command line. Note that Linux needs to detect you are using Xen before using earlyprintk. If you need earlier, then what I usually do is hacking xen_raw_console_write() (in drivers/tty/hvc/hvc_xen.c) and replace 'if (xen_domain())' with 'if (1)'. > > I don't think you're going to get a great deal of enthusiasm on this > list for Xen 4.8.5, unfortunately; most people around here work off > Xen's staging branch, and I'd be surprised to hear of anyone having > tried a 5.7 Linux kernel with Xen 4.8.5. I can understand why you > might start there from the existing patch series though. Right, 4.8.5 is now out of support and we improved Xen quite a lot since then. As a general recommendation, I would suggest to move the series to the latest staging once you get it working on 4.8.5. However, I don't see any reason why 5.7 wouldn't boot on 4.8.5. I will have a look at your stack trace and answer there. Best regards, -- Julien Grall