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 lists1p.gnu.org (lists1p.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 70181C43458 for ; Thu, 2 Jul 2026 13:11:52 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wfHC6-0007TM-2Q; Thu, 02 Jul 2026 09:11:06 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wfHC4-0007Sy-15 for qemu-devel@nongnu.org; Thu, 02 Jul 2026 09:11:04 -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 1wfHC0-000626-R0 for qemu-devel@nongnu.org; Thu, 02 Jul 2026 09:11:03 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1782997858; 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=M3vgRq6beZepQVfinCafFcx9OLUjR6eiaENnfMnPJOY=; b=ahOGQ0Y3sv0xMUZMEBkCABhn+uGDP/3MHwHpGesexWH7bpfXjCyg6K8ULeh3/b3uRhNTYB j1rlJutRGTfJ6k/ebUTuI/bQtmfH6jym9e8zPPPWF0azFp8hReI9w15iCgfOk7OJafAtub W2rqsJoCdNuP1tjlPoscyQPxlMdxHmA= Received: from mx-prod-mc-06.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-277-75f2G2CCNVOXI0Z_bN2gsw-1; Thu, 02 Jul 2026 09:10:55 -0400 X-MC-Unique: 75f2G2CCNVOXI0Z_bN2gsw-1 X-Mimecast-MFC-AGG-ID: 75f2G2CCNVOXI0Z_bN2gsw_1782997853 Received: from mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.95]) (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-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 4B93518333A0; Thu, 2 Jul 2026 13:10:53 +0000 (UTC) Received: from redhat.com (unknown [10.44.33.186]) by mx-prod-int-10.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A330336F04; Thu, 2 Jul 2026 13:10:49 +0000 (UTC) Date: Thu, 2 Jul 2026 14:10:46 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Markus Armbruster Cc: qemu-devel@nongnu.org, devel@lists.libvirt.org, =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , Paolo Bonzini , "Dr. David Alan Gilbert" , Alex =?utf-8?Q?Benn=C3=A9e?= , Christian Brauner , Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= , Peter Krempa Subject: Re: [PATCH v5 05/35] monitor: minimal conversion of monitors to QOM Message-ID: References: <20260624173752.2928717-1-berrange@redhat.com> <20260624173752.2928717-6-berrange@redhat.com> <87o6gs1buf.fsf@pond.sub.org> <87tsqi4zk6.fsf@pond.sub.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87tsqi4zk6.fsf@pond.sub.org> User-Agent: Mutt/2.3.2 (2026-04-26) X-Scanned-By: MIMEDefang 3.6 on 10.30.177.95 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=-0.445, 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_H3=0.001, RCVD_IN_MSPIKE_WL=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 Wed, Jul 01, 2026 at 03:19:53PM +0200, Markus Armbruster wrote: > Daniel P. Berrangé writes: > > > On Tue, Jun 30, 2026 at 01:55:52PM +0200, Markus Armbruster wrote: > >> Daniel P. Berrangé writes: > >> > >> > This introduces a Monitor QOM object, with MonitorHMP and > >> > MonitorQMP subclasses. This is the bare minimum conversion > >> > of just the type declarations and replacing g_new/g_free > >> > with object_new/object_unref. > >> > > >> > Reviewed-by: Marc-André Lureau > >> > Tested-by: Peter Krempa > >> > Signed-off-by: Daniel P. Berrangé > >> > --- > >> > include/monitor/monitor.h | 11 ++++++++++- > >> > monitor/hmp.c | 29 +++++++++++++++++++++++++++-- > >> > monitor/monitor-internal.h | 18 ++++++++++++++++-- > >> > monitor/monitor.c | 18 ++++++++++++++++-- > >> > monitor/qmp-cmds.c | 15 ++++++++------- > >> > monitor/qmp.c | 29 +++++++++++++++++++++++++++-- > >> > 6 files changed, 104 insertions(+), 16 deletions(-) > >> > > >> > diff --git a/include/monitor/monitor.h b/include/monitor/monitor.h > >> > index b9642b58ba..2e9f9e12e9 100644 > >> > --- a/include/monitor/monitor.h > >> > +++ b/include/monitor/monitor.h > >> > @@ -5,8 +5,17 @@ > >> > #include "qapi/qapi-types-misc.h" > >> > #include "qemu/readline.h" > >> > #include "exec/hwaddr.h" > >> > +#include "qom/object.h" > >> > + > >> > +#define TYPE_MONITOR "monitor" > >> > +OBJECT_DECLARE_TYPE(Monitor, MonitorClass, MONITOR); > >> > + > >> > +#define TYPE_MONITOR_HMP "monitor-hmp" > >> > +OBJECT_DECLARE_TYPE(MonitorHMP, MonitorHMPClass, MONITOR_HMP); > >> > + > >> > +#define TYPE_MONITOR_QMP "monitor-qmp" > >> > +OBJECT_DECLARE_TYPE(MonitorQMP, MonitorQMPClass, MONITOR_QMP); > >> > > >> > -typedef struct MonitorHMP MonitorHMP; > >> > typedef struct MonitorOptions MonitorOptions; > >> > > >> > #define QMP_REQ_QUEUE_LEN_MAX 8 > >> > diff --git a/monitor/hmp.c b/monitor/hmp.c > >> > index 4e4468424a..81047d2513 100644 > >> > --- a/monitor/hmp.c > >> > +++ b/monitor/hmp.c > >> > @@ -43,6 +43,20 @@ > >> > #include "system/block-backend.h" > >> > #include "trace.h" > >> > > >> > +OBJECT_DEFINE_TYPE(MonitorHMP, monitor_hmp, MONITOR_HMP, MONITOR); > >> > + > >> > +static void monitor_hmp_finalize(Object *obj) > >> > +{ > >> > +} > >> > + > >> > +static void monitor_hmp_class_init(ObjectClass *cls, const void *data) > >> > +{ > >> > +} > >> > + > >> > +static void monitor_hmp_init(Object *obj) > >> > +{ > >> > +} > >> > + > >> > static void monitor_command_cb(void *opaque, const char *cmdline, > >> > void *readline_opaque) > >> > { > >> > @@ -1526,10 +1540,21 @@ static void monitor_readline_flush(void *opaque) > >> > > >> > void monitor_new_hmp(Chardev *chr, bool use_readline, Error **errp) > >> > { > >> > - MonitorHMP *mon = g_new0(MonitorHMP, 1); > >> > + MonitorHMP *mon; > >> > + static int counter; > >> > + g_autofree char *id = g_strdup_printf("hmpcompat%d", counter++); > >> > >> Hmm. The system picking IDs is problematic when they can clash with the > >> user's IDs. If we had an ounce of common sense, we'd restrict both > >> across the board so they cannot clash. But we don't. > >> > >> We need an ID here, because we need to make the new object the child of > >> something (actually: child of /objects/), which requires a child name. > >> > >> Non-problem with -object / object-add, because @id is mandatory there. > >> > >> Non-problem with -device / device_add, because we use separate parents > >> for devices with and without @id (/machine/peripheral/ and > >> /machine/peripheral-anon/, plus the /machine/unattached/ orphanage). > >> > >> Example for an existing problem: > >> > >> $ qemu-system-x86_64 -nodefaults -monitor stdio -chardev null,id=chr0 -mon id=compat_monitor0,chardev=chr0 > >> qemu-system-x86_64: -mon id=compat_monitor0,chardev=chr0: Duplicate ID 'compat_monitor0' for mon > >> > >> Example for a problem created by this series: > >> > >> $ qemu-system-x86_64 -nodefaults -display none -S -monitor stdio -chardev null,id=chr0 -object monitor-hmp,id=hmpcompat0,chardev=chr0 > >> qemu-system-x86_64: -monitor stdio: attempt to add duplicate property 'hmpcompat0' to object (type 'container') > >> > >> I readily admit that these clashes are *unlikely*. Still, do we really > >> want to define an interface that claims to let you pick any ID, then > >> rejects some of them sometimes? Feels rather 1990s to me. At the very > >> least, cover the wart in the commit message. > > > > The way I looked at it was aything using -object with the new > > monitor-qmp/monitor-hmp types is new code. They can: > > > > 1. Trivially abide the warning about "hmpcompatNN" / "qmpcompatNN" > > being internal usage for compat syntax > > A wart you can easily cope with is still a wart. Oh well, we'll live. > However, the wart should be documented. > > > 2. Not use both -monitor and -object on the same QEMU instance > > so not have a clash between the two to begin with > > Management applications aware of the monitor QOM types should use > -object / object-add exclusively. > > Human users will use -monitor to save typing. If they then need to plug > an additional one at run time, they have no choice but use object-add. > Again, we'll live. > > > The remaining danger where is some existing code using -object with > > a *non-monitor* type, and calling it "hmpcompatNN" / "qmpcompatNN", > > which would be insanity. Never say never, but I think that's an > > acceptable risk. > > The risk is acceptable. The documentation complexity that comes with > the wart bothers me. > > Could we use id_generate()? Since we want to re-use the QemuOpts ID present in -monitor/-qmp, I'm going to stick with "compat_monitorNNN" and get rid of use of 'hmpcompatNN' and 'qmpcompatNN'. id_generate() does not help here because it forces a "#" prefix onto the ID which then (intentionally) violates id_wellformed() which object_new_xxx() validates. 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 :|