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 <md...@redhat.com> Signed-off-by: Amit Shah <amit.s...@redhat.com> --- 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 <pbonz...@redhat.com>
