If reading/writing from the device have occured before migration data
has arrived, the migration data might no longer be relvant, and we
disconnect the client.
When restoring migration data, we also restore data that is addressed to
the device, and that might have been originated from more than 1
message. When the write buffer that is assoicated with this data is
released, we need to free all the relevant tokens.
The list of attached char_devices will be used in the next patch
for notifying each instance of SpiceCharDeviceState when the vm
is started or stopped.
SpiceCharDeviceState manages the (1) write-to-device queue
(2) wakeup and reading from the device (3) client tokens (4)
sending messages from the device to the client/s, considering the
available tokens.
SpiceCharDeviceState can be also stopped and started. When the device
is stopped, no reading or writing is done from/to the device. Messages
addressed from the client to the device are being queued.
Later, an api for stop/start will be added to spice.h and it should
be called from qemu.
This patch does not yet remove the wakeup callback from
SpiceCharDeviceState, but once all the char devices (agent/spicevmc/smartcard)
code will switch to the new implementation, SpiceCharDeviceState
will be moved to the c file and its reference to the wakeup callback will be removed.
