gs:address on all the cores to cause a debug breakpoint (#DB), and also a VM-exit is configured to happen when a debug breakpoint arrived (using the exception bitmap for the #DB). As a result, a VM-exit occurs in the case of any changes to the
gs:. Whenever Windows tries to write on this address, it means that a thread is changed as it stores the information about the threads on this address. This way, we will be notified that a thread is changed.