Merge remote-tracking branch 'remotes/dgilbert/tags/pull-migration-20210208a' into...

Merge remote-tracking branch 'remotes/dgilbert/tags/pull-migration-20210208a' into staging

Migration pull 2021-02-08

v2
  Dropped vmstate: Fix memory leak in vmstate_handle_alloc
    Broke on Power
  Added migration: only check page size match if RAM postcopy is enabled

# gpg: Signature made Mon 08 Feb 2021 11:28:14 GMT
# gpg:                using RSA key 45F5C71B4A0CB7FB977A9FA90516331EBC5BFDE7
# gpg: Good signature from "Dr. David Alan Gilbert (RH2) <dgilbert@redhat.com>" [full]
# Primary key fingerprint: 45F5 C71B 4A0C B7FB 977A  9FA9 0516 331E BC5B FDE7

* remotes/dgilbert/tags/pull-migration-20210208a: (27 commits)
  migration: only check page size match if RAM postcopy is enabled
  migration: introduce snapshot-{save, load, delete} QMP commands
  iotests: fix loading of common.config from tests/ subdir
  iotests: add support for capturing and matching QMP events
  migration: introduce a delete_snapshot wrapper
  migration: wire up support for snapshot device selection
  migration: control whether snapshots are ovewritten
  block: rename and alter bdrv_all_find_snapshot semantics
  block: allow specifying name of block device for vmstate storage
  block: add ability to specify list of blockdevs during snapshot
  migration: stop returning errno from load_snapshot()
  migration: Make save_snapshot() return bool, not 0/-1
  block: push error reporting into bdrv_all_*_snapshot functions
  migration: Display the migration blockers
  migration: Add blocker information
  migration: Fix a few absurdly defective error messages
  migration: Fix cache_init()'s "Failed to allocate" error messages
  migration: Clean up signed vs. unsigned XBZRLE cache-size
  migration: Fix migrate-set-parameters argument validation
  migration: introduce 'userfaultfd-wrlat.py' script
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>