These 2 patches are used to handle broken page wrt migration. Generally there
are 2 cases: the broken page occur before migration, and the broken page occur
during migration.
Patch 01 handles the case that broken page occurred before migration: At the
sender, the broken page would not be copied to target while its pfn_type and pfn
number would be transferred to target, so that at target, it would set p2m as
p2m_ram_broken for broken page.
Patch 02 handles the case that broken page occurred during migration: At the
sender, marks the broken page to dirty bitmap, so that at copypages stage of
migration, its pfn_type and pfn number would transfer to target. At the target,
it would set p2m as p2m_ram_broken for broken page.
Thanks,
Jinsong
