memory: Add FlatView foreach function

Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Signed-off-by: Alexander Bulekov <alxndr@bu.edu>
Message-Id: <20201023150746.107063-2-alxndr@bu.edu>
Signed-off-by: Thomas Huth <thuth@redhat.com>

include/exec/memory.h

@@ -719,6 +719,11 @@ static inline FlatView *address_space_to_flatview(AddressSpace *as)
     return qatomic_rcu_read(&as->current_map);
 }
 
+typedef int (*flatview_cb)(Int128 start,
+                           Int128 len,
+                           const MemoryRegion*, void*);
+
+void flatview_for_each_range(FlatView *fv, flatview_cb cb , void *opaque);
 
 /**
  * struct MemoryRegionSection: describes a fragment of a #MemoryRegion