diff options
Diffstat (limited to 'hw/char/virtio-serial-bus.c')
| -rw-r--r-- | hw/char/virtio-serial-bus.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c index c86814f059..d14e872d34 100644 --- a/hw/char/virtio-serial-bus.c +++ b/hw/char/virtio-serial-bus.c @@ -465,6 +465,37 @@ static void handle_output(VirtIODevice *vdev, VirtQueue *vq) static void handle_input(VirtIODevice *vdev, VirtQueue *vq) { + /* + * Users of virtio-serial would like to know when guest becomes + * writable again -- i.e. if a vq had stuff queued up and the + * guest wasn't reading at all, the host would not be able to + * write to the vq anymore. Once the guest reads off something, + * we can start queueing things up again. However, this call is + * made for each buffer addition by the guest -- even though free + * buffers existed prior to the current buffer addition. This is + * done so as not to maintain previous state, which will need + * additional live-migration-related changes. + */ + VirtIOSerial *vser; + VirtIOSerialPort *port; + VirtIOSerialPortClass *vsc; + + vser = VIRTIO_SERIAL(vdev); + port = find_port_by_vq(vser, vq); + + if (!port) { + return; + } + vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port); + + /* + * If guest_connected is false, this call is being made by the + * early-boot queueing up of descriptors, which is just noise for + * the host apps -- don't disturb them in that case. + */ + if (port->guest_connected && port->host_connected && vsc->guest_writable) { + vsc->guest_writable(port); + } } static uint32_t get_features(VirtIODevice *vdev, uint32_t features) |