From nobody Fri Nov 7 15:29:19 2025 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; dmarc=fail(p=none dis=none) header.from=redhat.com Return-Path: Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) by mx.zohomail.com with SMTPS id 1548274611759612.1514286591345; Wed, 23 Jan 2019 12:16:51 -0800 (PST) Received: from localhost ([127.0.0.1]:41189 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gmOx8-00021a-Nm for importer@patchew.org; Wed, 23 Jan 2019 15:16:50 -0500 Received: from eggs.gnu.org ([209.51.188.92]:50068) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gmOjq-0007DE-HB for qemu-devel@nongnu.org; Wed, 23 Jan 2019 15:03:07 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gmOck-0002KB-KU for qemu-devel@nongnu.org; Wed, 23 Jan 2019 14:55:47 -0500 Received: from mx1.redhat.com ([209.132.183.28]:51426) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gmOck-0002JN-CS; Wed, 23 Jan 2019 14:55:46 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 881CF4025D; Wed, 23 Jan 2019 19:55:44 +0000 (UTC) Received: from t460s.redhat.com (ovpn-116-22.ams2.redhat.com [10.36.116.22]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0C1375D6A9; Wed, 23 Jan 2019 19:55:40 +0000 (UTC) From: David Hildenbrand To: qemu-devel@nongnu.org Date: Wed, 23 Jan 2019 20:55:20 +0100 Message-Id: <20190123195527.29575-3-david@redhat.com> In-Reply-To: <20190123195527.29575-1-david@redhat.com> References: <20190123195527.29575-1-david@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Wed, 23 Jan 2019 19:55:44 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH RFCv2 2/9] qdev: Let machine hotplug handler to override bus hotplug handler X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Murilo Opsfelder Araujo , Collin Walling , Eduardo Habkost , "Michael S . Tsirkin" , Cornelia Huck , David Hildenbrand , "Dr . David Alan Gilbert" , Markus Armbruster , Halil Pasic , Christian Borntraeger , qemu-s390x@nongnu.org, qemu-ppc@nongnu.org, Paolo Bonzini , Igor Mammedov , David Gibson , Richard Henderson Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: Igor Mammedov it will allow to return another hotplug handler than the default one for a specific bus based device type. Which is needed to handle non trivial plug/unplug sequences that need the access to resources configured outside of bus where device is attached. That will allow for returned hotplug handler to orchestrate wiring in arbitrary order, by chaining other hotplug handlers when it's needed. PS: It could be used for hybrid virtio-mem and virtio-pmem devices where it will return machine as hotplug handler which will do necessary wiring at machine level and then pass control down the chain to bus specific hotplug handler. Example of top level hotplug handler override and custom plug sequence: some_machine_get_hotplug_handler(machine){ if (object_dynamic_cast(OBJECT(dev), TYPE_SOME_BUS_DEVICE)) { return HOTPLUG_HANDLER(machine); } return NULL; } some_machine_device_plug(hotplug_dev, dev) { if (object_dynamic_cast(OBJECT(dev), TYPE_SOME_BUS_DEVICE)) { /* do machine specific initialization */ some_machine_init_special_device(dev) /* pass control to bus specific handler */ hotplug_handler_plug(dev->parent_bus->hotplug_handler, dev) } } Reviewed-by: David Gibson Signed-off-by: Igor Mammedov Signed-off-by: David Hildenbrand --- hw/core/qdev.c | 6 ++---- include/hw/qdev-core.h | 11 +++++++++++ 2 files changed, 13 insertions(+), 4 deletions(-) diff --git a/hw/core/qdev.c b/hw/core/qdev.c index 278cc094ec..7ad45c0bd6 100644 --- a/hw/core/qdev.c +++ b/hw/core/qdev.c @@ -235,12 +235,10 @@ HotplugHandler *qdev_get_machine_hotplug_handler(Devi= ceState *dev) =20 HotplugHandler *qdev_get_hotplug_handler(DeviceState *dev) { - HotplugHandler *hotplug_ctrl; + HotplugHandler *hotplug_ctrl =3D qdev_get_machine_hotplug_handler(dev); =20 - if (dev->parent_bus && dev->parent_bus->hotplug_handler) { + if (hotplug_ctrl =3D=3D NULL && dev->parent_bus) { hotplug_ctrl =3D dev->parent_bus->hotplug_handler; - } else { - hotplug_ctrl =3D qdev_get_machine_hotplug_handler(dev); } return hotplug_ctrl; } diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h index 0a84c42756..9081fb0030 100644 --- a/include/hw/qdev-core.h +++ b/include/hw/qdev-core.h @@ -281,6 +281,17 @@ void qdev_init_nofail(DeviceState *dev); void qdev_set_legacy_instance_id(DeviceState *dev, int alias_id, int required_for_version); HotplugHandler *qdev_get_machine_hotplug_handler(DeviceState *dev); +/** + * qdev_get_hotplug_handler: Get handler responsible for device wiring + * + * Find HOTPLUG_HANDLER for @dev that provides [pre|un]plug callbacks for = it. + * + * Note: in case @dev has a parent bus, it will be returned as handler unl= ess + * machine handler overrides it. + * + * Returns: pointer to object that implements TYPE_HOTPLUG_HANDLER interfa= ce + * or NULL if there aren't any. + */ HotplugHandler *qdev_get_hotplug_handler(DeviceState *dev); void qdev_unplug(DeviceState *dev, Error **errp); void qdev_simple_device_unplug_cb(HotplugHandler *hotplug_dev, --=20 2.17.2