When memory page is converted from private to shared, the original private memory is back'ed by guest_memfd. Introduce ram_block_discard_guest_memfd_range() for discarding memory in guest_memfd. Originally-from: Isaku Yamahata <isaku.yamahata@intel.com> Codeveloped-by: Xiaoyao Li <xiaoyao.li@intel.com> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> Reviewed-by: David Hildenbrand <david@redhat.com> --- Changes in v5: - Collect Reviewed-by from David; Changes in in v4: - Drop ram_block_convert_range() and open code its implementation in the next Patch.