[Qemu-devel] [STABLE v2] virtio-serial-bus: replay guest_open on migration

[Alon Levy <alevy@redhat.com>]

When migrating a host with with a spice agent running the mouse becomes
non operational after the migration. This is rhbz #725965.

The problem is that after migration spice doesn't know the guest agent is open.
Spice is just a char dev here. And a chardev cannot query it's device, the
device has to let the chardev know when it is open. Right now after migration
the chardev which is recreated is in it's default state, which assumes the
guest is disconnected.

Char devices carry no information across migration, but the virtio-serial does
already carry the guest_connected state. This patch passes that bit to the
chardev.

Signed-off-by: Alon Levy <alevy@redhat.com>
---
 hw/virtio-serial-bus.c |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c
index c5eb931..4a6d932 100644
--- a/hw/virtio-serial-bus.c
+++ b/hw/virtio-serial-bus.c
@@ -618,6 +618,7 @@ static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
     for (i = 0; i < nr_active_ports; i++) {
         uint32_t id;
         bool host_connected;
+        VirtIOSerialPortInfo *info;
 
         id = qemu_get_be32(f);
         port = find_port_by_id(s, id);
@@ -626,6 +627,11 @@ static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)
         }
 
         port->guest_connected = qemu_get_byte(f);
+        info = DO_UPCAST(VirtIOSerialPortInfo, qdev, port->dev.info);
+        if (port->guest_connected && info->guest_open) {
+            /* replay guest open */
+            info->guest_open(port);
+        }
         host_connected = qemu_get_byte(f);
         if (host_connected != port->host_connected) {
             /*
-- 
1.7.6