The pages that are mapped to zero_page_pfn are not dumped but information
where are they located is required for lazy restore.
Note that get_pagemap users presumed that zero pages are not a part of the
pagemap and these pages were just silently skipped during memory restore.
At the moment I preserve this semantics and force get_pagemap to skip zero
pages.
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Pavel Emelyanov <xemul@virtuozzo.com>