Re: [Qemu-devel] [RFC] save/restore with icount enabled.

[Paolo Bonzini <pbonzini@redhat.com>]

Il 15/05/2013 11:31, KONRAD Frédéric ha scritto:
> Hi,
> 
> We are trying to do a simple save/restore on the VM with icount enabled.
> 
> We saw that qemu_icount_bias and qemu_icount in cpus.c are not
> saved/restored,
> and icount_extra, icount_decr in CPUState neither, so the vm_clock is just
> growing normally after restoring the VM is that normal?
> 
> We think that this is making the "replay" undeterminastic, which is bad for
> reverse execution.
> 
> Is there a good reason for them not being saved?

No.  You can probably move icount to timers_state.  Something like
zeroing qemu_icount in cpu_disable_ticks() is required in order to save
qemu_icount_bias like the other members of timers_state.  There is even
a dummy field that you can reuse to avoid the pain of adding a
subsection to vmstate_timers. :)

Paolo

> 
> Thanks,
> Fred
> 
>