Re: [Qemu-devel] [PATCH 12/18] Insert event_tap_mmio() to cpu_physical_memory_rw() in exec.c.

[Takuya Yoshikawa]

> >> What kind of mmio should be traced here, device or CPU originated? Or both?
> >>
> >> Jan
> >>
> >>
> > 
> > To let Kemari replay outputs upon failover, tracing CPU originated
> > mmio (specifically write requests) should be enough.
> > IIUC, we can reproduce device originated mmio as a result of cpu
> > originated mmio.
> > 

Sorry, but I don't understand why it is safe yet.

The problem is not if the mmio's are to be replayed but if replaying
them will produce the same result, is it?

In other words, is it really idempotent?

Takuya

> 
> OK, I see.
> 
> But this tap will only work for KVM. I think you either have to catch
> the other paths that TCG could take as well or maybe better move the
> hook into kvm-all - then it's absolutely clear that this is no generic
> feature.
> 
> Jan
>