Add ref/unref calls at the following places:
- places where memory regions are stashed by a listener and
used outside the BQL (including in Xen or KVM).
- memory_region_find callsites
- creation of aliases and containers (only the aliased/contained
region gets a reference to avoid loops)
- around calls to del_subregion/add_subregion, where the region
could disappear after the first call
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
So far, the size of all regions passed to listeners could fit in 64 bits,
because artificial regions (containers and aliases) are eliminated by
the memory core, leaving only device regions which have reasonable sizes
An IOMMU however cannot be eliminated by the memory core, and may have
an artificial size, hence we may need 65 bits to represent its size.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
