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 A322BC2BD09 for ; Tue, 9 Jul 2024 16:49:09 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sRE0q-00087t-H4; Tue, 09 Jul 2024 12:48:20 -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 1sRE0p-000872-1H for qemu-devel@nongnu.org; Tue, 09 Jul 2024 12:48:19 -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 1sRE0n-000525-7Z for qemu-devel@nongnu.org; Tue, 09 Jul 2024 12:48:18 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1720543695; 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=fOEIMAMP/0J5WABOUJtCCyKZtgwP+NSk+WseQw6WNjc=; b=MhJyZCWgvyehhkKPo8QMwIXB1RB4rj3Rz+yv8W/V/RiEEUrI5Y/1NPUgKM5e3eOzX1nyRi 6nFLZsgsJswk06+Vp4A870cmK/QaKNcl+hdyKq/Cy77SwwQNvBgptGCtiby6gOLyAHks9x DtgaQpW2C6U+vKZEzUmRAbzl0OVmn84= 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-664-HQ-A14CWPlC4WDuH3ZsV6A-1; Tue, 09 Jul 2024 12:48:12 -0400 X-MC-Unique: HQ-A14CWPlC4WDuH3ZsV6A-1 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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1178A1956046; Tue, 9 Jul 2024 16:48:11 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.106]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 3175A3000183; Tue, 9 Jul 2024 16:48:08 +0000 (UTC) Date: Tue, 9 Jul 2024 17:48:05 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Stefan Hajnoczi Cc: qemu-devel@nongnu.org, Eduardo Habkost , Paolo Bonzini , Markus Armbruster Subject: Re: [PATCH] qdev-monitor: QAPIfy QMP device_add Message-ID: References: <20240708143027.480821-1-stefanha@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20240708143027.480821-1-stefanha@redhat.com> User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 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: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.144, 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, 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?= 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, Jul 08, 2024 at 04:30:27PM +0200, Stefan Hajnoczi wrote: > The QMP device_add monitor command converts the QDict arguments to > QemuOpts and then back again to QDict. This process only supports scalar > types. Device properties like virtio-blk-pci's iothread-vq-mapping (an > array of objects) are silently dropped by qemu_opts_from_qdict() during > the QemuOpts conversion even though QAPI is capable of validating them. > As a result, hotplugging virtio-blk-pci devices with the > iothread-vq-mapping property does not work as expected (the property is > ignored). It's time to QAPIfy QMP device_add! > > Get rid of the QemuOpts conversion in qmp_device_add() and call > qdev_device_add_from_qdict() with from_json=true. Using the QMP > command's QDict arguments directly allows non-scalar properties. > > The HMP is also adjusted since qmp_device_add()'s now expects properly > typed JSON arguments and cannot be used from HMP anymore. Move the code > that was previously in qmp_device_add() (with QemuOpts conversion and > from_json=false) into hmp_device_add() so that its behavior is > unchanged. > > This patch changes the behavior of QMP device_add but not HMP > device_add. QMP clients that sent incorrectly typed device_add QMP > commands no longer work. This is a breaking change but clients should be > using the correct types already. See the netdev_add QAPIfication in > commit db2a380c8457 for similar reasoning. > > Markus helped me figure this out and even provided a draft patch. The > code ended up very close to what he suggested. > > Suggested-by: Markus Armbruster > Cc: Daniel P. Berrangé > Signed-off-by: Stefan Hajnoczi > --- > system/qdev-monitor.c | 41 ++++++++++++++++++++++++++++------------- > 1 file changed, 28 insertions(+), 13 deletions(-) I think we're justified in saying that applications should have been using the correct types already. On the libvirt side we already switched to using JSON for -device, which has forced us to ensure we're using the correct types. So the risk of converting device_add is minimal from libvirt's POV. Other non-libvirt mgmt apps might get tripped up. Fixing those should not be too difficult and fixed code would remain compatible with older QEMU versions too. Reviewed-by: Daniel P. Berrangé > > diff --git a/system/qdev-monitor.c b/system/qdev-monitor.c > index 6af6ef7d66..1427aa173c 100644 > --- a/system/qdev-monitor.c > +++ b/system/qdev-monitor.c > @@ -849,18 +849,9 @@ void hmp_info_qdm(Monitor *mon, const QDict *qdict) > > void qmp_device_add(QDict *qdict, QObject **ret_data, Error **errp) > { > - QemuOpts *opts; > DeviceState *dev; > > - opts = qemu_opts_from_qdict(qemu_find_opts("device"), qdict, errp); > - if (!opts) { > - return; > - } > - if (!monitor_cur_is_qmp() && qdev_device_help(opts)) { > - qemu_opts_del(opts); > - return; > - } > - dev = qdev_device_add(opts, errp); > + dev = qdev_device_add_from_qdict(qdict, true, errp); > if (!dev) { > /* > * Drain all pending RCU callbacks. This is done because > @@ -872,8 +863,6 @@ void qmp_device_add(QDict *qdict, QObject **ret_data, Error **errp) > * to the user > */ > drain_call_rcu(); > - > - qemu_opts_del(opts); > return; > } > object_unref(OBJECT(dev)); > @@ -967,8 +956,34 @@ void qmp_device_del(const char *id, Error **errp) > void hmp_device_add(Monitor *mon, const QDict *qdict) > { > Error *err = NULL; > + QemuOpts *opts; > + DeviceState *dev; > > - qmp_device_add((QDict *)qdict, NULL, &err); > + opts = qemu_opts_from_qdict(qemu_find_opts("device"), qdict, &err); > + if (!opts) { > + goto out; > + } > + if (qdev_device_help(opts)) { > + qemu_opts_del(opts); > + return; > + } > + dev = qdev_device_add(opts, &err); > + if (!dev) { > + /* > + * Drain all pending RCU callbacks. This is done because > + * some bus related operations can delay a device removal > + * (in this case this can happen if device is added and then > + * removed due to a configuration error) > + * to a RCU callback, but user might expect that this interface > + * will finish its job completely once qmp command returns result > + * to the user > + */ > + drain_call_rcu(); > + > + qemu_opts_del(opts); > + } > + object_unref(OBJECT(dev)); > +out: > hmp_handle_error(mon, err); > } > > -- > 2.45.2 > 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 :|