Milestones in Program Execution

A good thing to do, if we're mixing hardware and software TMs would be to have the hardware TM, after it fails (due to a context switch or an abort), handle the work it has done so far to the software TM.

The problem is, how should the software know where the hardware is at?

My half-baked idea, which I plan on pursuing later, is to have milestones. Like a statement which saves a milestone (number or something like that) every N statements. This when the work is handed to the software, we know where we should proceed from.

This half-baked idea also involves a log somehow which rolls back the last few statements to the milestone.