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 3D6C4FF5137 for ; Tue, 7 Apr 2026 19:23:41 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wABW6-0007nC-Gj; Tue, 07 Apr 2026 14:51:14 -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 1wABTk-0003JL-43 for qemu-devel@nongnu.org; Tue, 07 Apr 2026 14:48:48 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wA4Ar-0008GA-MY for qemu-devel@nongnu.org; Tue, 07 Apr 2026 07:00:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1775559648; 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=WvRynJhQip/PgDiQeybk+Pla8b86NTdSmr7OTQiLRtE=; b=O2b40csAD46ofm1zJfQzXbl6bL4EUNnLBugiyksyryCPQbZeukgKn/mN/8uiI8+nkjWioS dqUghRw3zIBBv9tHmh/DLRVNMweDfQs0o72ooMbf6C/lrIIeMdHrAHYHLqEL9rtKHWVZYZ A6j/qFEkLAgTzl7IVSRE0Une2Rg+jbw= Received: from mx-prod-mc-05.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-498-BaOfJlOOM-eP7Tv7CoDusw-1; Tue, 07 Apr 2026 07:00:45 -0400 X-MC-Unique: BaOfJlOOM-eP7Tv7CoDusw-1 X-Mimecast-MFC-AGG-ID: BaOfJlOOM-eP7Tv7CoDusw_1775559644 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1EC8F19560AE; Tue, 7 Apr 2026 11:00:44 +0000 (UTC) Received: from redhat.com (headnet01.pony-001.prod.iad2.dc.redhat.com [10.2.32.101]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id C519C1955D84; Tue, 7 Apr 2026 11:00:41 +0000 (UTC) Date: Tue, 7 Apr 2026 12:00:38 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Christian Brauner Cc: qemu-devel@nongnu.org, Markus Armbruster , Eric Blake , Fabiano Rosas , Laurent Vivier , Paolo Bonzini , Thomas Huth , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Subject: Re: [PATCH v3 0/5] monitor: add dynamic QMP monitor hotplug support Message-ID: References: <20260407-work-qmp-monitor-hotplug-v3-0-cb259800fffb@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260407-work-qmp-monitor-hotplug-v3-0-cb259800fffb@kernel.org> User-Agent: Mutt/2.2.14 (2025-02-20) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 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: -25 X-Spam_score: -2.6 X-Spam_bar: -- X-Spam_report: (-2.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.54, 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_H2=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_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: qemu development 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 Tue, Apr 07, 2026 at 09:32:44AM +0200, Christian Brauner wrote: > QEMU supports runtime hotplug for chardevs, devices, block backends, > and netdevs. Monitors are the only major subsystem that lacks this -- > all QMP monitors must be configured at launch via -mon or -qmp CLI > options. > > This series adds monitor-add, monitor-remove, and query-monitors QMP > commands so that management tools can create independent QMP sessions > on demand at runtime. > > I've implemented a QMP-to-Varlink bridge in systemd. This allows > systemd-vmspawn to control virtual machines and containers through a > unified Varlink interface. Varlink allows protocol upgrades. For > example, it is possible to switch from Varlink to say http. I'm > allowing Varlink clients to upgrade from the Varlink interface to the > native QMP interface. Such clients get a new monitor assigned that > allows them to manage the virtual machine directly via QMP. The main > monitor remains unaffected and tied to the generic Varlink interface. We > can't pre-allocate monitors as we have no control over how many protocol > upgrades we actually get but it won't just be one. And having unused > monitors around really isn't ideal either. > > Having the ability to hotplug monitors would really be helpful. I'm not > yet super well-versed in qemu internals so this might be done wrong but > testing works so far. Can you say if AI agents/LLMs were used in creating these patches ? > > My systemd patch that triggered this is at > https://github.com/systemd/systemd/pull/41449. > > The usage pattern mirrors chardev hotplug: > > -> chardev-add id=qmp-extra backend=socket,... > -> monitor-add id=extra-qmp chardev=qmp-extra > [client connects to socket, gets QMP greeting, negotiates, sends commands] > -> monitor-remove id=extra-qmp > -> chardev-remove id=qmp-extra With regards, Daniel -- |: https://berrange.com ~~ https://hachyderm.io/@berrange :| |: https://libvirt.org ~~ https://entangle-photo.org :| |: https://pixelfed.art/berrange ~~ https://fstop138.berrange.com :|