Re: [Qemu-devel] [PATCH] hw/virtio-serial-bus: replay guest open on destination

[Amit Shah]

On (Sun) 25 Nov 2012 [15:39:14], Alon Levy wrote:
> When migrating a host with with a spice agent running the mouse becomes
> non operational after the migration due to the agent state being
> inconsistent between the guest and the client if the client is using
> semi-seamless or switch host migration.
> 
> After migration the target client has never received the guest_open
> initiated spice message. Virtio-serial holds this state information and
> migrates it, so replay that over the chardev post migration. Fix is not
> spice specific but spice is the only client that cares about it.

Thanks for continuing to pursue this :)

> rhbz #725965.
> ---
>  hw/virtio-serial-bus.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c
> index efa8a81..ccce1fa 100644
> --- a/hw/virtio-serial-bus.c
> +++ b/hw/virtio-serial-bus.c
> @@ -641,6 +641,7 @@ static void virtio_serial_post_load_timer_cb(void *opaque)
>      VirtIOSerial *s = opaque;
>      VirtIOSerialPort *port;
>      uint8_t host_connected;
> +    VirtIOSerialPortClass *vsc;
>  
>      for (i = 0 ; i < s->post_load.nr_active_ports; ++i) {
>          port = s->post_load.connected[i].port;
> @@ -653,6 +654,11 @@ static void virtio_serial_post_load_timer_cb(void 
> *opaque)
>              send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN,
>                                 port->host_connected);
>          }
> +        vsc = VIRTIO_SERIAL_PORT_GET_CLASS(port);
> +        if (port->guest_connected && vsc->guest_open) {
> +            /* replay guest open */
> +            vsc->guest_open(port);
> +        }

I think the last time we discussed this, my objection was the guest
isn't really doing an open again, and since spice depends on the
guest's connectedness, spice should have a post-load hook or a similar
bh that would query virtio-serial for guest connectedness status, and,
if connected, do whatever setup is necessary.

Adding Gerd and Markus as I think they were involved in the discussion
last time as well.

                Amit