Re: finding all the places in an AddressSpace that alias a specific address

[Paolo Bonzini <pbonzini@redhat.com>]

On 12/03/21 17:05, Peter Maydell wrote:
> For that I would need to find all the addresses in an AddressSpace
> that alias vecbase, so that we can call rom_ptr() on all of them.
> I think something like this would work:
> 
>      hwaddr xlat, len;
>      RCU_READ_LOCK_GUARD();
>      FlatView *fv = address_space_to_flatview(s->as);
>      MemoryRegion *main_mr = flatview_translate(fv, vecbase, &xlat, &len,
>                                                 false, MEMTXATTRS_UNSPECIFIED);
>      flatview_for_each_range(fv, callback_fn, ...);
> 
> where callback_fn() does:
>      if (mr != main_mr) {
>          return;
>      }
>      do arithmetic with flatview range start and len, etc to figure
>      out the overall address in the AS corresponding to vecbase
>      rom = rom_ptr(that_addr);
>      ...
> 
> Does this seem like it would work ? Is there a nicer way ?

Yes, it should work.  I can't think of a nicer way, except of course 
wrapping it in a nicer that hides the walk.

For what it's worth, it wouldn't be a problem to make FlatRange public 
and export FOR_EACH_FLAT_RANGE as well.

Paolo