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 CE50CC433F5 for ; Wed, 5 Jan 2022 15:05:48 +0000 (UTC) Received: from localhost ([::1]:52934 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1n57rH-0005Yv-Cx for qemu-devel@archiver.kernel.org; Wed, 05 Jan 2022 10:05:47 -0500 Received: from eggs.gnu.org ([209.51.188.92]:38152) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n57hy-0004Fr-UT for qemu-devel@nongnu.org; Wed, 05 Jan 2022 09:56:11 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:41944) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1n57hw-0006TR-Bw for qemu-devel@nongnu.org; Wed, 05 Jan 2022 09:56:09 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1641394567; 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=MwjPy4MIdFIVG5v9epn/tIirI7eyoHJO32Af3UI9wDM=; b=NJ8hYXQNEum2PqDKgzOXqIyWAHQaBebFf6fOdFwYAmJUbho/tls8ORhDfVRy9VRW0C1P2W yhQ+z4QcW9Lkbw5tijl5w1wWOOns/VuKMOyeEvzZi/VvIJIQJzlMxlgpVSoPdl8tq6BWos iWaq9+eCUYb3lAPrmj8/bSZ5YG2Eftc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-481-GZ58Mn0XNvWjXp8agmCexQ-1; Wed, 05 Jan 2022 09:56:01 -0500 X-MC-Unique: GZ58Mn0XNvWjXp8agmCexQ-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 15E608031E6; Wed, 5 Jan 2022 14:55:40 +0000 (UTC) Received: from redhat.com (unknown [10.33.36.150]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 454987DE22; Wed, 5 Jan 2022 14:55:38 +0000 (UTC) Date: Wed, 5 Jan 2022 14:55:35 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Laurent Vivier Subject: Re: [PATCH 1/1] softmmu: fix device deletion events with -device JSON syntax Message-ID: References: <20220105123847.4047954-1-berrange@redhat.com> <20220105123847.4047954-2-berrange@redhat.com> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/2.1.3 (2021-09-10) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit 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: -31 X-Spam_score: -3.2 X-Spam_bar: --- X-Spam_report: (-3.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.372, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=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?= Cc: Kevin Wolf , Eduardo Habkost , Thomas Huth , Peter Krempa , qemu-devel@nongnu.org, Markus Armbruster , Paolo Bonzini , Eric Blake Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Jan 05, 2022 at 03:49:12PM +0100, Laurent Vivier wrote: > On 05/01/2022 13:38, Daniel P. Berrangé wrote: > > The -device JSON syntax impl leaks a reference on the created > > DeviceState instance. As a result when you hot-unplug the > > device, the device_finalize method won't be called and thus > > it will fail to emit the required DEVICE_DELETED event. > > > > A 'json-cli' feature was previously added against the > > 'device_add' QMP command QAPI schema to indicated to mgmt > > apps that -device supported JSON syntax. Given the hotplug > > bug that feature flag is no unusable for its purpose, so > > Not sure to understand: do you mean "now unusable"? An application wants to known whether QEMU can support JSON syntax with -device. If they look for the 'json-cli' feature as a witness, they'll end up using JSON with QEMU 6.2 which is giving them broken hotplug. This is unusable for any non-trivial use cases. So we need a new witness to indicate whether JSON is viable with -device, that only the newly fixed QEMU will report. > > > we add a new 'json-cli-hotplug' feature to indicate the > > -device supports JSON without breaking hotplug. > > > > Fixes: https://gitlab.com/qemu-project/qemu/-/issues/802 > > Signed-off-by: Daniel P. Berrangé > > --- > > qapi/qdev.json | 5 ++++- > > softmmu/vl.c | 4 +++- > > tests/qtest/device-plug-test.c | 19 +++++++++++++++++++ > > 3 files changed, 26 insertions(+), 2 deletions(-) > > > > diff --git a/qapi/qdev.json b/qapi/qdev.json > > index 69656b14df..26cd10106b 100644 > > --- a/qapi/qdev.json > > +++ b/qapi/qdev.json > > @@ -44,6 +44,9 @@ > > # @json-cli: If present, the "-device" command line option supports JSON > > # syntax with a structure identical to the arguments of this > > # command. > > +# @json-cli-hotplug: If present, the "-device" command line option supports JSON > > +# syntax without the reference counting leak that broke > > +# hot-unplug > > # > > # Notes: > > # > > @@ -74,7 +77,7 @@ > > { 'command': 'device_add', > > 'data': {'driver': 'str', '*bus': 'str', '*id': 'str'}, > > 'gen': false, # so we can get the additional arguments > > - 'features': ['json-cli'] } > > + 'features': ['json-cli', 'json-cli-hotplug'] } > > ## > > # @device_del: > > diff --git a/softmmu/vl.c b/softmmu/vl.c > > index d9e4c619d3..b1fc7da104 100644 > > --- a/softmmu/vl.c > > +++ b/softmmu/vl.c > > @@ -2684,6 +2684,7 @@ static void qemu_create_cli_devices(void) > > qemu_opts_foreach(qemu_find_opts("device"), > > device_init_func, NULL, &error_fatal); > > QTAILQ_FOREACH(opt, &device_opts, next) { > > + DeviceState *dev; > > loc_push_restore(&opt->loc); > > /* > > * TODO Eventually we should call qmp_device_add() here to make sure it > > @@ -2692,7 +2693,8 @@ static void qemu_create_cli_devices(void) > > * from the start, so call qdev_device_add_from_qdict() directly for > > * now. > > */ > > - qdev_device_add_from_qdict(opt->opts, true, &error_fatal); > > + dev = qdev_device_add_from_qdict(opt->opts, true, &error_fatal); > > + object_unref(OBJECT(dev)); > > loc_pop(&opt->loc); > > } > > rom_reset_order_override(); > > diff --git a/tests/qtest/device-plug-test.c b/tests/qtest/device-plug-test.c > > index 559d47727a..ad79bd4c14 100644 > > --- a/tests/qtest/device-plug-test.c > > +++ b/tests/qtest/device-plug-test.c > > @@ -77,6 +77,23 @@ static void test_pci_unplug_request(void) > > qtest_quit(qtest); > > } > > +static void test_pci_unplug_json_request(void) > > +{ > > + QTestState *qtest = qtest_initf( > > + "-device '{\"driver\": \"virtio-mouse-pci\", \"id\": \"dev0\"}'"); > > + > > + /* > > + * Request device removal. As the guest is not running, the request won't > > + * be processed. However during system reset, the removal will be > > + * handled, removing the device. > > + */ > > + device_del(qtest, "dev0"); > > + system_reset(qtest); > > You can use qpci_unplug_acpi_device_test() to process the request... but I > see this is done like that too in test_pci_unplug_request() > > > + wait_device_deleted_event(qtest, "dev0"); > > + > > + qtest_quit(qtest); > > +} > > + > > static void test_ccw_unplug(void) > > { > > QTestState *qtest = qtest_initf("-device virtio-balloon-ccw,id=dev0"); > > @@ -145,6 +162,8 @@ int main(int argc, char **argv) > > */ > > qtest_add_func("/device-plug/pci-unplug-request", > > test_pci_unplug_request); > > + qtest_add_func("/device-plug/pci-unplug-json-request", > > + test_pci_unplug_json_request); > > if (!strcmp(arch, "s390x")) { > > qtest_add_func("/device-plug/ccw-unplug", > > Reviewed-by: Laurent Vivier > 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 :|