From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58539) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gWjsP-0006AV-60 for qemu-devel@nongnu.org; Tue, 11 Dec 2018 10:23:13 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gWjsK-00038U-54 for qemu-devel@nongnu.org; Tue, 11 Dec 2018 10:23:13 -0500 Received: from mx1.redhat.com ([209.132.183.28]:55388) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gWjsJ-000385-UC for qemu-devel@nongnu.org; Tue, 11 Dec 2018 10:23:08 -0500 Date: Tue, 11 Dec 2018 16:23:03 +0100 From: Igor Mammedov Message-ID: <20181211162303.2e581899@redhat.com> In-Reply-To: <1544469254-11629-1-git-send-email-akrowiak@linux.ibm.com> References: <1544469254-11629-1-git-send-email-akrowiak@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] 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 Cc: qemu-devel@nongnu.org, thuth@redhat.com, armbru@redhat.com, f4bug@amsat.org, pasic@linux.ibm.com, borntraeger@de.ibm.com, pbonzini@redhat.com On Mon, 10 Dec 2018 14:14:14 -0500 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 >= 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. > > Signed-off-by: Tony Krowiak > --- > hw/core/qdev.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/hw/core/qdev.c b/hw/core/qdev.c > index 6b3cc55b27c2..b35b0bf27925 100644 > --- a/hw/core/qdev.c > +++ b/hw/core/qdev.c > @@ -59,6 +59,8 @@ static void bus_remove_child(BusState *bus, DeviceState *child) > snprintf(name, sizeof(name), "child[%d]", kid->index); > QTAILQ_REMOVE(&bus->children, kid, sibling); > > + bus->max_index--; that might cause problem when bus is allowed to has more than 1 device and unplugged device is not the last one. In that case bus_add_child() might create a child with duplicate name. > + > /* This gives back ownership of kid->child back to us. */ > object_property_del(OBJECT(bus), name, NULL); > object_unref(OBJECT(kid->child));