From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35825) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gXoYW-0004nh-GH for qemu-devel@nongnu.org; Fri, 14 Dec 2018 09:35:10 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gXoYT-0006AR-9O for qemu-devel@nongnu.org; Fri, 14 Dec 2018 09:35:08 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:44076 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 1gXoYT-0006A6-37 for qemu-devel@nongnu.org; Fri, 14 Dec 2018 09:35:05 -0500 Received: from pps.filterd (m0098417.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.22/8.16.0.22) with SMTP id wBEETDCQ105266 for ; Fri, 14 Dec 2018 09:35:04 -0500 Received: from e13.ny.us.ibm.com (e13.ny.us.ibm.com [129.33.205.203]) by mx0a-001b2d01.pphosted.com with ESMTP id 2pccs6w6wq-1 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=NOT) for ; Fri, 14 Dec 2018 09:35:04 -0500 Received: from localhost by e13.ny.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Fri, 14 Dec 2018 14:35:03 -0000 References: <1544718402-8703-1-git-send-email-akrowiak@linux.ibm.com> <92cc8705-33cf-49ff-b63f-6297b81df02d@linux.ibm.com> From: Tony Krowiak Date: Fri, 14 Dec 2018 09:35:00 -0500 MIME-Version: 1.0 In-Reply-To: <92cc8705-33cf-49ff-b63f-6297b81df02d@linux.ibm.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Message-Id: 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: pmorel@linux.ibm.com, qemu-devel@nongnu.org Cc: pasic@linux.ibm.com, mammedo@redhat.com On 12/14/18 4:16 AM, Pierre Morel wrote: > 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= =20 >> 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= =20 >> a device >> is unplugged from the bus. This patch fixes that problem. >=20 > 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. >=20 > With the comment amended in this direction: Good point, I should have changed that when I refactored this fix. >=20 > Reviewed-by: Pierre Morel >=20 >=20 >> >> Signed-off-by: Tony Krowiak >> --- >> =C2=A0 hw/core/qdev.c=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 = | 3 +++ >> =C2=A0 include/hw/qdev-core.h | 1 + >> =C2=A0 qdev-monitor.c=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 = | 2 +- >> =C2=A0 3 files changed, 5 insertions(+), 1 deletion(-) >> >> 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,=20 >> DeviceState *child) >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0 snprintf(name, sizeof(name), "child[%d]", kid->index); >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0 QTAILQ_REMOVE(&bus->children, kid, sibling); >> >> +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 bu= s->num_children--; >> + >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0 /* This gives back ownership of kid->child back to us.=C2=A0 */ >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0 object_property_del(OBJECT(bus), name, NULL); >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0 object_unref(OBJECT(kid->child)); >> @@ -73,6 +75,7 @@ static void bus_add_child(BusState *bus, DeviceState= =20 >> *child) >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 char name[32]; >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 BusChild *kid =3D g_malloc0(sizeof(*kid= )); >> >> +=C2=A0=C2=A0=C2=A0 bus->num_children++; >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 kid->index =3D bus->max_index++; >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 kid->child =3D child; >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 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 { >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 HotplugHandler *hotplug_handler; >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 int max_index; >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 bool realized; >> +=C2=A0=C2=A0=C2=A0 int num_children; >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 QTAILQ_HEAD(ChildrenHead, BusChild) chi= ldren; >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 QLIST_ENTRY(BusState) sibling; >> =C2=A0 }; >> 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,=20 >> char *elem) >> =C2=A0 static inline bool qbus_is_full(BusState *bus) >> =C2=A0 { >> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 BusClass *bus_class =3D BUS_GET_CLASS(b= us); >> -=C2=A0=C2=A0=C2=A0 return bus_class->max_dev && bus->max_index >=3D b= us_class->max_dev; >> +=C2=A0=C2=A0=C2=A0 return bus_class->max_dev && bus->num_children >=3D= =20 >> bus_class->max_dev; >> =C2=A0 } >> >> =C2=A0 /* >> >=20 >=20