From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37538) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gXjgP-0004cI-Aj for qemu-devel@nongnu.org; Fri, 14 Dec 2018 04:22:58 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gXjgK-0000sZ-B3 for qemu-devel@nongnu.org; Fri, 14 Dec 2018 04:22:57 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:45764 helo=mx0a-001b2d01.pphosted.com) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gXjgK-0000rz-0d for qemu-devel@nongnu.org; Fri, 14 Dec 2018 04:22:52 -0500 Received: from pps.filterd (m0098416.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wBE9JFPA077988 for ; Fri, 14 Dec 2018 04:22:50 -0500 Received: from e06smtp01.uk.ibm.com (e06smtp01.uk.ibm.com [195.75.94.97]) by mx0b-001b2d01.pphosted.com with ESMTP id 2pc9c2s7vv-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 14 Dec 2018 04:22:50 -0500 Received: from localhost by e06smtp01.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 14 Dec 2018 09:22:48 -0000 Reply-To: pmorel@linux.ibm.com References: <1544718402-8703-1-git-send-email-akrowiak@linux.ibm.com> From: Pierre Morel Date: Fri, 14 Dec 2018 10:22:43 +0100 MIME-Version: 1.0 In-Reply-To: <1544718402-8703-1-git-send-email-akrowiak@linux.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Message-Id: <938b657e-d10d-9aaa-ef17-7f28562faccf@linux.ibm.com> Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH v2] qdev/core: Can not replug device on bus that allows one device List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Tony Krowiak , qemu-devel@nongnu.org Cc: pasic@linux.ibm.com, imammedo@redhat.com On 13/12/2018 17:26, Tony Krowiak wrote: > If the maximum number of devices allowed on a bus is 1 and a device > which is plugged into the bus is subsequently unplugged, attempting to = replug > the device fails with error "Bus 'xxx' does not support hotplugging". > The "error" is detected in the qbus_is_full(BusState *bus) function > (qdev_monitor.c) because bus->max_index >=3D bus_class->max_dev. The > root of the problem is that the bus->max_index is not decremented when = a device > is unplugged from the bus. This patch fixes that problem. I think that the root of the problem is that the max_index is not the=20 right measure to determine the number of devices currently plugged. With the comment amended in this direction: Reviewed-by: Pierre Morel (resent after address correction) >=20 > Signed-off-by: Tony Krowiak > --- > hw/core/qdev.c | 3 +++ > include/hw/qdev-core.h | 1 + > qdev-monitor.c | 2 +- > 3 files changed, 5 insertions(+), 1 deletion(-) >=20 > diff --git a/hw/core/qdev.c b/hw/core/qdev.c > index 6b3cc55b27c2..956923f33520 100644 > --- a/hw/core/qdev.c > +++ b/hw/core/qdev.c > @@ -59,6 +59,8 @@ static void bus_remove_child(BusState *bus, DeviceSta= te *child) > snprintf(name, sizeof(name), "child[%d]", kid->index); > QTAILQ_REMOVE(&bus->children, kid, sibling); >=20 > + bus->num_children--; > + > /* This gives back ownership of kid->child back to us. *= / > object_property_del(OBJECT(bus), name, NULL); > object_unref(OBJECT(kid->child)); > @@ -73,6 +75,7 @@ static void bus_add_child(BusState *bus, DeviceState = *child) > char name[32]; > BusChild *kid =3D g_malloc0(sizeof(*kid)); >=20 > + bus->num_children++; > kid->index =3D bus->max_index++; > kid->child =3D child; > object_ref(OBJECT(kid->child)); > diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h > index a24d0dd566e3..521f0a947ead 100644 > --- a/include/hw/qdev-core.h > +++ b/include/hw/qdev-core.h > @@ -206,6 +206,7 @@ struct BusState { > HotplugHandler *hotplug_handler; > int max_index; > bool realized; > + int num_children; > QTAILQ_HEAD(ChildrenHead, BusChild) children; > QLIST_ENTRY(BusState) sibling; > }; > diff --git a/qdev-monitor.c b/qdev-monitor.c > index 07147c63bf8b..45a8ba49644c 100644 > --- a/qdev-monitor.c > +++ b/qdev-monitor.c > @@ -414,7 +414,7 @@ static DeviceState *qbus_find_dev(BusState *bus, ch= ar *elem) > static inline bool qbus_is_full(BusState *bus) > { > BusClass *bus_class =3D BUS_GET_CLASS(bus); > - return bus_class->max_dev && bus->max_index >=3D bus_class->max_de= v; > + return bus_class->max_dev && bus->num_children >=3D bus_class->max= _dev; > } >=20 > /* >=20 --=20 Pierre Morel Linux/KVM/QEMU in B=C3=B6blingen - Germany