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=-3.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 409F6C4742C for ; Tue, 10 Nov 2020 23:25:46 +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 BE1BD20781 for ; Tue, 10 Nov 2020 23:25:45 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BE1BD20781 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=m5p.com 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.24066.51121 (Exim 4.92) (envelope-from ) id 1kcd0w-0005CW-Pm; Tue, 10 Nov 2020 23:25:26 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 24066.51121; Tue, 10 Nov 2020 23:25:26 +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" Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1kcd0w-0005CP-Mb; Tue, 10 Nov 2020 23:25:26 +0000 Received: by outflank-mailman (input) for mailman id 24066; Tue, 10 Nov 2020 23:25:26 +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 1kcd0v-0005CI-Tj for xen-devel@lists.xenproject.org; Tue, 10 Nov 2020 23:25:25 +0000 Received: from mailhost.m5p.com (unknown [74.104.188.4]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id a377acb8-f98e-4998-8919-e2203896ffd4; Tue, 10 Nov 2020 23:25:24 +0000 (UTC) Received: from m5p.com (mailhost.m5p.com [IPv6:2001:470:1f07:15ff:0:0:0:f7]) by mailhost.m5p.com (8.15.2/8.15.2) with ESMTPS id 0AANPBFC043559 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Tue, 10 Nov 2020 18:25:17 -0500 (EST) (envelope-from ehem@m5p.com) Received: (from ehem@localhost) by m5p.com (8.15.2/8.15.2/Submit) id 0AANPAQB043558; Tue, 10 Nov 2020 15:25:10 -0800 (PST) (envelope-from ehem) 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 1kcd0v-0005CI-Tj for xen-devel@lists.xenproject.org; Tue, 10 Nov 2020 23:25:25 +0000 X-Inumbo-ID: a377acb8-f98e-4998-8919-e2203896ffd4 Received: from mailhost.m5p.com (unknown [74.104.188.4]) by us1-amaz-eas2.inumbo.com (Halon) with ESMTPS id a377acb8-f98e-4998-8919-e2203896ffd4; Tue, 10 Nov 2020 23:25:24 +0000 (UTC) Received: from m5p.com (mailhost.m5p.com [IPv6:2001:470:1f07:15ff:0:0:0:f7]) by mailhost.m5p.com (8.15.2/8.15.2) with ESMTPS id 0AANPBFC043559 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NO); Tue, 10 Nov 2020 18:25:17 -0500 (EST) (envelope-from ehem@m5p.com) Received: (from ehem@localhost) by m5p.com (8.15.2/8.15.2/Submit) id 0AANPAQB043558; Tue, 10 Nov 2020 15:25:10 -0800 (PST) (envelope-from ehem) Date: Tue, 10 Nov 2020 15:25:10 -0800 From: Elliott Mitchell To: Stefano Stabellini Cc: J??rgen Gro?? , Julien Grall , roman@zededa.com, xen-devel@lists.xenproject.org Subject: Re: Xen on RP4 Message-ID: <20201110232510.GA43420@mattapan.m5p.com> References: <20201023211941.GA90171@mattapan.m5p.com> <20201024053540.GA97417@mattapan.m5p.com> <4fcf4832-9266-443f-54d0-fa1fff4b6e14@xen.org> <20201026160316.GA20589@mattapan.m5p.com> <7a904044-8206-b45d-8ec2-d4e48b07ea83@xen.org> <20201028015423.GA33407@mattapan.m5p.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Thu, Oct 29, 2020 at 12:57:58PM -0700, Stefano Stabellini wrote: > On Thu, 29 Oct 2020, J??rgen Gro?? wrote: > > What about having a small domain parsing the ACPI booting first and use > > that information for booting dom0? > > > > That dom would be part of the Xen build and the hypervisor wouldn't need > > to gain all the ACPI AML logic. > > That could work, but in practice we don't have such a domain today -- > the infrastructure is missing. I wonder whether the bootloader (uboot or > grub) would know about the platform and might be able to pass that > information to Xen somehow. How long would such likely take to implement? This reads like a complicated project, and likely to take a while... Then would be the issue of efifb. I've been pondering allocate_memory_11() and coming up with a rather complicated potential problem. ACPI appears to potentially allow for non-power of 2 DMA ranges; I'm unaware of any such device, but the code should allow for such. I can imagine a device which has multiple DMA ranges. The ranges could be fully contained within each other, the ranges could partially overlap, or the ranges could be disjoint. Someone might wish to allocate all DMA-capable memory to domain 0, someone might wish to allocate less. Additionally if all DMA-capable memory is allocated to domain 0, some non-DMA-capable memory could be desired. Ideally Xen would move to non-DMA memory. This would protect Xen against a malicious domain 0 and allow allocating more DMA-capable memory to domain 0. This interacts with ballooning. If memory is removed from domain 0, non-DMA memory should be removed first. If domain 0 is allocated more memory, DMA memory should be added first (if any isn't allocated to domain 0). Then again I may be severely overthinking things. -- (\___(\___(\______ --=> 8-) EHM <=-- ______/)___/)___/) \BS ( | ehem+sigmsg@m5p.com PGP 87145445 | ) / \_CS\ | _____ -O #include O- _____ | / _/ 8A19\___\_|_/58D2 7E3D DDF4 7BA6 <-PGP-> 41D1 B375 37D0 8714\_|_/___/5445