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.gnu.org (lists.gnu.org [209.51.188.17]) (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 7B26DC433F5 for ; Tue, 14 Dec 2021 12:54:44 +0000 (UTC) Received: from localhost ([::1]:34938 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mx7KN-0007Cm-I6 for qemu-devel@archiver.kernel.org; Tue, 14 Dec 2021 07:54:43 -0500 Received: from eggs.gnu.org ([209.51.188.92]:45114) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mx7Ie-0005Kh-Sy for qemu-devel@nongnu.org; Tue, 14 Dec 2021 07:52:56 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:43050) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mx7Ib-0006Be-OJ for qemu-devel@nongnu.org; Tue, 14 Dec 2021 07:52:55 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1639486373; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=G043V05UymokKjm4XwQnrS6WB3UOvGAD2xrmh5+aK/k=; b=AXQ2WHqBMRLJ3DJESUtVT5lw3zqRIA/a4h9j0JzmNKLC46hlb9pPk6URFpJyOC8Cn+LWxg nSGEkxndhawj3tmYWwbDxcNYNgXEBJa2l0TbqSRGY8IKAaZPO1LCMTDvNUM/R1u6b8wi5z G3mvRxrt3ueZrNImfKw4fnAmFgk+F80= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-140-HfopJW6zN42dk5DgJZPicg-1; Tue, 14 Dec 2021 07:52:52 -0500 X-MC-Unique: HfopJW6zN42dk5DgJZPicg-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C0A3810168C8; Tue, 14 Dec 2021 12:52:50 +0000 (UTC) Received: from redhat.com (unknown [10.39.194.122]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B2EFA19EF9; Tue, 14 Dec 2021 12:52:47 +0000 (UTC) Date: Tue, 14 Dec 2021 12:52:43 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Juan Quintela Subject: Re: [PATCH v2 3/4] hw/display/vga-mmio: QOM'ify vga_mmio_init() as TYPE_VGA_MMIO Message-ID: References: <20211206224528.563588-1-f4bug@amsat.org> <20211206224528.563588-4-f4bug@amsat.org> <99ebc4fb-f061-1e57-da07-e66035bacf9b@redhat.com> <87o85jz912.fsf@secure.mitica> MIME-Version: 1.0 In-Reply-To: <87o85jz912.fsf@secure.mitica> User-Agent: Mutt/2.1.3 (2021-09-10) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.716, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Thomas Huth , qemu-devel@nongnu.org, "Dr. David Alan Gilbert" , =?utf-8?B?SGVydsOp?= Poussineau , Gerd Hoffmann , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Tue, Dec 14, 2021 at 01:05:29PM +0100, Juan Quintela wrote: > Thomas Huth wrote: > > On 06/12/2021 23.45, Philippe Mathieu-Daudé wrote: > >> Introduce TYPE_VGA_MMIO, a sysbus device. > >> While there is no change in the vga_mmio_init() > >> interface, this is a migration compatibility break > >> of the MIPS Acer Pica 61 Jazz machine (pica61). > > > > It's unfortunate, but as far as I know, it would be pretty difficult > > or even impossible to get this done without versioned machine types? > > So IMHO it's ok to break this in this case here. > > Hi > > My understanding is that outside of x86*, and now ppc, arm and s390, > no one else really cares about migration compatibility. I am not even > sure if they really care about migration at all O:-) > > So, if the code is better for other reasons, I will not wonder about > migration compatibility. Essentially if it has versioned machine types, then migration ABI compat is mandatory. If it doesn't have versioned machine types then migration API compat explicitly doesn't exist. There are no versioned machine types for MIPS, so migration compat is a non-issue. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|