Re: [Qemu-devel] [PATCH 1/2] memory: Provide separate handling of unassigned io ports accesses

[Paolo Bonzini]

On Aug 05 2013, Peter Maydell wrote:
> > But even if we would, the IO container now catches all accesses, so
> > the system memory region will never have its default handler run for
> > that window.
> 
> Yes, that is the point -- before the IO container caught all
> accesses, the default handler that would run would be the
> system memory region, but now that the IO container has
> default read/write ops they will take precedence. So this
> would be a behaviour change if there are any boards set up
> like this. (I'm not sure there are any, though.)

Before 1.6 this would have happened anyway.  Before 1.6, all
I/O accesses would go through cpu_in/cpu_out, and would never
hit the system memory region.  So Jan's patch is effectively
restoring old behavior.

Paolo