memory: abstract address space operations

memory: abstract address space operations

Prepare for multiple address space support by abstracting away the details
of registering a memory range with qemu's flat representation into an
AddressSpace object.

Note operations which are memory specific are not abstracted, since they will
never be called on I/O address spaces anyway.

Reviewed-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>