From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48936) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X6zT1-0002ax-4O for qemu-devel@nongnu.org; Tue, 15 Jul 2014 05:56:17 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1X6zSu-0002Ju-VO for qemu-devel@nongnu.org; Tue, 15 Jul 2014 05:56:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:63922) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1X6zSu-0002JR-Np for qemu-devel@nongnu.org; Tue, 15 Jul 2014 05:56:04 -0400 Received: from int-mx13.intmail.prod.int.phx2.redhat.com (int-mx13.intmail.prod.int.phx2.redhat.com [10.5.11.26]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s6F9u2Mf015285 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK) for ; Tue, 15 Jul 2014 05:56:03 -0400 Message-ID: <53C4FAAF.90503@redhat.com> Date: Tue, 15 Jul 2014 11:55:59 +0200 From: Paolo Bonzini MIME-Version: 1.0 References: <339156532cdc68672d36d0aa0b1b85cf596b2135.1405417943.git.amit.shah@redhat.com> In-Reply-To: <339156532cdc68672d36d0aa0b1b85cf596b2135.1405417943.git.amit.shah@redhat.com> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v2 for-2.1 1/1] virtio-serial-bus: keep port 0 reserved for virtconsole even on unplug List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Amit Shah , qemu list Cc: Amos Kong Il 15/07/2014 11:52, Amit Shah ha scritto: > We keep port 0 reserved for compat with older guests, where only > virtio-console was expected. Even if a system is started without a > virtio-console port, port #0 is kept aside. However, after a > virtconsole port is unplugged, port id 0 became available, and the next > hotplug of a virtserialport caused failure due to it not being a console > port. > > Steps to reproduce: > > $ ./x86_64-softmmu/qemu-system-x86_64 -m 512 -cpu host -enable-kvm -device virtio-serial-pci -monitor stdio -vnc :1 > QEMU 2.0.91 monitor - type 'help' for more information > (qemu) device_add virtconsole,id=p1 > (qemu) device_del p1 > (qemu) device_add virtserialport,id=p1 > Port number 0 on virtio-serial devices reserved for virtconsole devices for backward compatibility. > Device 'virtserialport' could not be initialized > (qemu) quit > > Reported-by: dengmin > Signed-off-by: Amit Shah > > --- > v2: > - move calculation of 'i' inside if stmt too (Paolo) > - re-word comment > --- > hw/char/virtio-serial-bus.c | 14 +++++++++++--- > 1 file changed, 11 insertions(+), 3 deletions(-) > > diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c > index 07bebc0..917e93e 100644 > --- a/hw/char/virtio-serial-bus.c > +++ b/hw/char/virtio-serial-bus.c > @@ -797,10 +797,18 @@ static void add_port(VirtIOSerial *vser, uint32_t port_id) > static void remove_port(VirtIOSerial *vser, uint32_t port_id) > { > VirtIOSerialPort *port; > - unsigned int i; > > - i = port_id / 32; > - vser->ports_map[i] &= ~(1U << (port_id % 32)); > + /* > + * Don't mark port 0 removed -- we explicitly reserve it for > + * backward compat with older guests, ensure a virtconsole device > + * unplug virtconsole retains the reservation. > + */ > + if (port_id) { > + unsigned int i; > + > + i = port_id / 32; > + vser->ports_map[i] &= ~(1U << (port_id % 32)); > + } > > port = find_port_by_id(vser, port_id); > /* > Reviewed-by: Paolo Bonzini