Hi!
I recently debugged record/replay for some platform which uses PIO access for IDE. Handlers for these operations are called through BHs. Scheduling new BH does not create a signal for the vCPU to suspend the execution and process the main loop events (in record/replay we synchronize these two threads). Therefore vCPU may execute 10000000 instruction until BH processing and the guest software may get a timeout. I thought about replacing BH to the timers with period=0. This solution has the following properties: 1. Avoid code duplication (BH and timers do virtually the same operations) 2. Timers affect the vCPU - adding new virtual timer suspends the execution to process the callback 3. Timers are deterministic in record/replay mode (virtual ones of course). We have similar deterministic concept for BHs, but selecting between virtual and realtime should be more familiar for other developers. 4. Timers require a little bit more code, but this could be solved with better interfaces What do you think about this? Did I miss anything? Pavel Dovgalyuk
