Merge tag 'migration-next-pull-request' of https://gitlab.com/peterx/qemu into staging

Migration pull request

- Fabiano's fixed-ram patches (1-5 only)
- Peter's cleanups on multifd tls IOC referencing
- Steve's cpr patches for vfio (migration patches only)
- Fabiano's fix on mbps stats racing with COMPLETE state
- Fabiano's fix on return path thread hang

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# gpg:                using EDDSA key B9184DC20CC457DACF7DD1A93B5FCCCDF3ABD706
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# gpg: Good signature from "Peter Xu <xzpeter@gmail.com>" [marginal]
# gpg:                 aka "Peter Xu <peterx@redhat.com>" [marginal]
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* tag 'migration-next-pull-request' of https://gitlab.com/peterx/qemu: (25 commits)
  migration: Use migrate_has_error() in close_return_path_on_source()
  migration: Join the return path thread before releasing to_dst_file
  migration: Fix qmp_query_migrate mbps value
  migration: options incompatible with cpr
  migration: update cpr-reboot description
  migration: stop vm for cpr
  migration: notifier error checking
  migration: refactor migrate_fd_connect failures
  migration: per-mode notifiers
  migration: MigrationNotifyFunc
  migration: remove postcopy_after_devices
  migration: MigrationEvent for notifiers
  migration: convert to NotifierWithReturn
  migration: remove error from notifier data
  notify: pass error to notifier with return
  migration/multifd: Drop unnecessary helper to destroy IOC
  migration/multifd: Cleanup outgoing_args in state destroy
  migration/multifd: Make multifd_channel_connect() return void
  migration/multifd: Drop registered_yank
  migration/multifd: Cleanup TLS iochannel referencing
  ...

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

1 files changed, 24 insertions, 13 deletions

diff --git a/qapi/migration.json b/qapi/migration.json
index 7303e57..0b33a71 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -636,19 +636,30 @@
 #
 # @normal: the original form of migration. (since 8.2)
 #
-# @cpr-reboot: The migrate command saves state to a file, allowing one to
-#              quit qemu, reboot to an updated kernel, and restart an updated
-#              version of qemu.  The caller must specify a migration URI
-#              that writes to and reads from a file.  Unlike normal mode,
-#              the use of certain local storage options does not block the
-#              migration, but the caller must not modify guest block devices
-#              between the quit and restart.  To avoid saving guest RAM to the
-#              file, the memory backend must be shared, and the @x-ignore-shared
-#              migration capability must be set.  Guest RAM must be non-volatile
-#              across reboot, such as by backing it with a dax device, but this
-#              is not enforced.  The restarted qemu arguments must match those
-#              used to initially start qemu, plus the -incoming option.
-#              (since 8.2)
+# @cpr-reboot: The migrate command stops the VM and saves state to the URI.
+#     After quitting qemu, the user resumes by running qemu -incoming.
+#
+#     This mode allows the user to quit qemu, and restart an updated version
+#     of qemu.  The user may even update and reboot the OS before restarting,
+#     as long as the URI persists across a reboot.
+#
+#     Unlike normal mode, the use of certain local storage options does not
+#     block the migration, but the user must not modify guest block devices
+#     between the quit and restart.
+#
+#     This mode supports vfio devices provided the user first puts the guest
+#     in the suspended runstate, such as by issuing guest-suspend-ram to the
+#     qemu guest agent.
+#
+#     Best performance is achieved when the memory backend is shared and the
+#     @x-ignore-shared migration capability is set, but this is not required.
+#     Further, if the user reboots before restarting such a configuration, the
+#     shared backend must be be non-volatile across reboot, such as by backing
+#     it with a dax device.
+#
+#     cpr-reboot may not be used with postcopy, colo, or background-snapshot.
+#
+#     (since 8.2)
 ##
 { 'enum': 'MigMode',
   'data': [ 'normal', 'cpr-reboot' ] }