On Mon, 10 Oct 2022 at 16:21, Jason A. Donenfeld <ja...@zx2c4.com> wrote:
>
> On Mon, Oct 10, 2022 at 11:54:50AM +0100, Peter Maydell wrote:
> > The error is essentially the record-and-replay subsystem saying "the
> > replay just asked for a random number at point when the recording
> > did not ask for one, and so there's no 'this is what the number was'
> > info in the record".
> >
> > I have had a quick look, and I think the reason for this is that
> > load_snapshot() ("reset the VM state to the snapshot state stored in the
> > disk image or migration stream") does a system reset. The replay
> > process involves a lot of "load state from a snapshot and play
> > forwards from there" operations. It doesn't expect that load_snapshot()
> > would result in something reading random data, but now that we are
> > calling qemu_guest_getrandom() in a reset hook, that happens.
>
> Hmm... so this seems like a bug in the replay code then? Shouldn't that
> reset handler get hit during both passes, so the entry should be in
> each?No, because record is just "reset the system, record all the way to the end stop", but replay is "set the system to the point we want to start at by using load_snapshot, play from there", and depending on the actions you do in the debugger like reverse-continue we might repeatedly do "reload that snapshot (implying a system reset) and play from there" multiple times. thanks -- PMM
