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 9E299CAC5A7 for ; Mon, 22 Sep 2025 11:34:35 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1v0eoH-0001CI-Lj; Mon, 22 Sep 2025 07:34:22 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1v0eoA-00013X-IW for qemu-devel@nongnu.org; Mon, 22 Sep 2025 07:34:14 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1v0eo5-00023Q-DG for qemu-devel@nongnu.org; Mon, 22 Sep 2025 07:34:14 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1758540842; 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:in-reply-to:in-reply-to: references:references; bh=fWYCZB5j6pPSCDPlgb0T5FFaVHM2yye2okBw2y8rlYE=; b=ZSZpgmQQUcPZ2EuZgiglbdZ6wlncgr/1B3M1V+bq4UcA2r5ntFqKgtWqA7Vw1YNP+53KO3 +fbmGUT4tm8ZaND/GImtAs6iHXCTGCaTFeA1jSxqBBTrgIGfubprUICaaUVdhVaLZqaTkk DpVuHG2C5/Q8CTG82oYUgzSS0HF+f6A= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-613-KgaOEq40O0GPXOqMaIdTAw-1; Mon, 22 Sep 2025 07:33:59 -0400 X-MC-Unique: KgaOEq40O0GPXOqMaIdTAw-1 X-Mimecast-MFC-AGG-ID: KgaOEq40O0GPXOqMaIdTAw_1758540838 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4739C1801FAD; Mon, 22 Sep 2025 11:33:32 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.69]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id D795E30002CC; Mon, 22 Sep 2025 11:33:29 +0000 (UTC) Date: Mon, 22 Sep 2025 12:33:26 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: "Michael S. Tsirkin" Cc: Christian Speich , qemu-devel@nongnu.org, Stefano Garzarella , Alex =?utf-8?Q?Benn=C3=A9e?= Subject: Re: [PATCH] virtio: vhost-user-device: Make user creatable again Message-ID: References: <20250919-vhost-user-device-creatable-v1-1-87eefeea7f68@avm.de> <20250919160526-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20250919160526-mutt-send-email-mst@kernel.org> User-Agent: Mutt/2.2.14 (2025-02-20) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.442, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, SPF_HELO_PASS=-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?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Fri, Sep 19, 2025 at 04:07:19PM -0400, Michael S. Tsirkin wrote: > On Fri, Sep 19, 2025 at 04:30:53PM +0200, Christian Speich wrote: > > This removes the change introduced in [1] that prevents the use of > > vhost-user-device and vhost-user-device-pci on unpatched QEMU builds. > > > > [1]: 6275989647efb708f126eb4f880e593792301ed4 > > > > Signed-off-by: Christian Speich > > --- > > vhost-user-device and vhost-user-device-pci started out as user > > creatable devices. This was changed in [1] when the vhost-user-base was > > introduced. > > > > The reason given is to prevent user confusion. Searching qemu-discuss or > > google for "vhost-user-device" I've seen no confused users. > > > > Our use case is to provide wifi emulation using "vhost-user-device-pci", > > which currently is working fine with the QEMU 9.0.2 present in Ubuntu > > 24.04. With newer QEMU versions we now need to patch, distribute and > > maintain our own QEMU packages, which is non-trivial. > > > > So I want to propose lifting this restriction to make this feature > > usable without a custom QEMU. > > > > [1]: 6275989647efb708f126eb4f880e593792301ed4 > > The confusion is after someone reuses the ID you are claiming without > telling anyone and then linux guests will start binding that driver to > your device. > > > We want people doing this kind of thing to *at a minimum* > go ahead and register a device id with the virtio TC, > but really to write and publish a spec. Wanting people to register a device ID is a social problem and we're trying to apply a technical hammer to it, which is rarely an productive approach. If we want to demonstrate that vhost-user-device is "risky", then how about we rename it to have an 'x-' prefix and thus disclaim any support for it, but none the less allow its use. Document it as an experimental device, and if it breaks, users get to keep both pieces. It seems like it would be useful before any virtio spec submission as a mechanism by which users can experiment to finese their ideas prior to getting to the point of needing to make a spec proposal. With 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 :|