In a Hot-Swap application, the DLL will not lock. However, if the clock is stopped and restarted, or if the device is reconfigured after the board is plugged-in, the DLL will lock. It will also lock if the board is powered up normally (not Hot-Swapped).
In a Hot-Swap application, the reset pin of the DLL should be used. It should be tied to the global reset or another signal that will reset the DLL on power-up.