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 D0E48C27C55 for ; Mon, 10 Jun 2024 18:27:18 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sGjjS-0005hq-Uv; Mon, 10 Jun 2024 14:27:03 -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 1sGjjI-0005gO-1L for qemu-devel@nongnu.org; Mon, 10 Jun 2024 14:26:52 -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 1sGjjG-0006pw-8f for qemu-devel@nongnu.org; Mon, 10 Jun 2024 14:26:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1718044008; 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=wDKPwfTMvPEdBysezOfWfcB12MRhGMTru7l7+W2DslE=; b=eqSujr7FN7QKFSnrHEACOYlk7nVIO/8xaGH9NcizKKoV6URFoM6s+bth1ci4rcu9KPR24Y ODkHgeI6vMSst028j1kHZEm1//0fQwiQSTqmU0l77LgNGFtAnHB6Do3UDuwUXyfW4TDDLp ZPMA85AAoYxG4Gam7Vk9cwic9w1yRwg= Received: from mx-prod-mc-04.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-136-XQutqeZXOk-Dq7aiGw_Y0A-1; Mon, 10 Jun 2024 14:26:45 -0400 X-MC-Unique: XQutqeZXOk-Dq7aiGw_Y0A-1 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (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-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id A17AE19560A2; Mon, 10 Jun 2024 18:26:42 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.32]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 9DDE619560AA; Mon, 10 Jun 2024 18:26:36 +0000 (UTC) Date: Mon, 10 Jun 2024 19:26:33 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Cc: Markus Armbruster , "Dr. David Alan Gilbert" , qemu-devel@nongnu.org, Yanan Wang , Richard Henderson , Eric Farman , Thomas Huth , Eric Blake , Christian Borntraeger , qemu-s390x@nongnu.org, Eduardo Habkost , Ilya Leoshkevich , Halil Pasic , Marcel Apfelbaum , David Hildenbrand , Paolo Bonzini Subject: Re: [RFC PATCH 2/3] monitor: Allow passing HMP arguments to QMP HumanReadableText API Message-ID: References: <20240610175852.21215-1-philmd@linaro.org> <20240610175852.21215-3-philmd@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20240610175852.21215-3-philmd@linaro.org> User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 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: 11 X-Spam_score: 1.1 X-Spam_bar: + X-Spam_report: (1.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.143, 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_SBL_CSS=3.335, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=no 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 Mon, Jun 10, 2024 at 07:58:51PM +0200, Philippe Mathieu-Daudé wrote: > Allow HMP commands implemented using the HumanReadableText API > (via the HMPCommand::cmd_info_hrt handler) to pass arguments > to the QMP equivalent command. The arguments are serialized as > a JSON dictionary. > > Signed-off-by: Philippe Mathieu-Daudé > --- > docs/devel/writing-monitor-commands.rst | 15 ++++++++++++++- > qapi/machine.json | 24 ++++++++++++++++++++++++ > include/monitor/monitor.h | 3 ++- > monitor/monitor-internal.h | 2 +- > accel/tcg/monitor.c | 4 ++-- > hw/core/loader.c | 2 +- > hw/core/machine-qmp-cmds.c | 9 +++++---- > hw/usb/bus.c | 2 +- > monitor/hmp-target.c | 3 ++- > monitor/hmp.c | 11 +++++++---- > 10 files changed, 59 insertions(+), 16 deletions(-) > > diff --git a/docs/devel/writing-monitor-commands.rst b/docs/devel/writing-monitor-commands.rst > index 930da5cd06..843458e52c 100644 > --- a/docs/devel/writing-monitor-commands.rst > +++ b/docs/devel/writing-monitor-commands.rst > @@ -561,6 +561,7 @@ returns a ``HumanReadableText``:: > # Since: 6.2 > ## > { 'command': 'x-query-roms', > + 'data': { 'json-args': 'str'}, > 'returns': 'HumanReadableText', > 'features': [ 'unstable' ] } > > @@ -578,7 +579,7 @@ Implementing the QMP command > The QMP implementation will typically involve creating a ``GString`` > object and printing formatted data into it, like this:: > > - HumanReadableText *qmp_x_query_roms(Error **errp) > + HumanReadableText *qmp_x_query_roms(const char *json_args, Error **errp) > { > g_autoptr(GString) buf = g_string_new(""); > Rom *rom; > @@ -596,6 +597,18 @@ object and printing formatted data into it, like this:: > The actual implementation emits more information. You can find it in > hw/core/loader.c. > > +For QMP command taking (optional) parameters, these parameters are > +serialized as a JSON dictionary, and can be retrieved using the QDict > +API. If the previous ``x-query-roms`` command were taking a "index" > +argument, it could be retrieved as:: > + > + HumanReadableText *qmp_x_query_roms(const char *json_args, Error **errp) > + { > + g_autoptr(GString) buf = g_string_new(""); > + QDict *qdict = qobject_to(QDict, qobject_from_json(json_args, &error_abort)); > + uint64_t index = qdict_get_int(qdict, "index"); > + ... > + } Passing json inside json is pretty gross, and throwing away a key benefit of QAPI - that it de-serializes the JSON into the actual data types that you need, avoiding manual & error prone code for unpacking args from a QDict. IMHO if a commend requires arguments, they should be modelled explicitly, and not use the cmd_info_hrt convenience handler which was only ever intended simple for no-arg 'info' commands. 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 :|