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

Migartion pull request for 20240304

- Bryan's fix on multifd compression level API
- Fabiano's mapped-ram series (base + multifd only)
- Steve's amend on cpr document in qapi/

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* tag 'migration-next-pull-request' of https://gitlab.com/peterx/qemu: (27 commits)
  migration/multifd: Document two places for mapped-ram
  tests/qtest/migration: Add a multifd + mapped-ram migration test
  migration/multifd: Add mapped-ram support to fd: URI
  migration/multifd: Support incoming mapped-ram stream format
  migration/multifd: Support outgoing mapped-ram stream format
  migration/multifd: Prepare multifd sync for mapped-ram migration
  migration/multifd: Add incoming QIOChannelFile support
  migration/multifd: Add outgoing QIOChannelFile support
  migration/multifd: Add a wrapper for channels_created
  migration/multifd: Allow receiving pages without packets
  migration/multifd: Allow multifd without packets
  migration/multifd: Decouple recv method from pages
  migration/multifd: Rename MultiFDSend|RecvParams::data to compress_data
  tests/qtest/migration: Add tests for mapped-ram file-based migration
  migration/ram: Add incoming 'mapped-ram' migration
  migration/ram: Add outgoing 'mapped-ram' migration
  migration: Add mapped-ram URI compatibility check
  migration/ram: Introduce 'mapped-ram' migration capability
  migration/qemu-file: add utility methods for working with seekable channels
  io: fsync before closing a file channel
  ...

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

# Conflicts:
#	migration/ram.c

1 files changed, 24 insertions, 18 deletions

diff --git a/qapi/migration.json b/qapi/migration.json
index 0b33a71ab4..62acc834af 100644
--- a/qapi/migration.json
+++ b/qapi/migration.json
@@ -531,6 +531,10 @@
 #     and can result in more stable read performance.  Requires KVM
 #     with accelerator property "dirty-ring-size" set.  (Since 8.1)
 #
+# @mapped-ram: Migrate using fixed offsets in the migration file for
+#     each RAM page.  Requires a migration URI that supports seeking,
+#     such as a file.  (since 9.0)
+#
 # Features:
 #
 # @deprecated: Member @block is deprecated.  Use blockdev-mirror with
@@ -555,7 +559,7 @@
            { 'name': 'x-ignore-shared', 'features': [ 'unstable' ] },
            'validate-uuid', 'background-snapshot',
            'zero-copy-send', 'postcopy-preempt', 'switchover-ack',
-           'dirty-limit'] }
+           'dirty-limit', 'mapped-ram'] }
 
 ##
 # @MigrationCapabilityStatus:
@@ -636,28 +640,30 @@
 #
 # @normal: the original form of migration. (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.
+# @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.
+#     This mode allows the user to quit QEMU, optionally update and
+#     reboot the OS, and restart QEMU.  If the user reboots, the URI
+#     must persist across the reboot, such as by using a file.
 #
-#     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.
+#     Unlike normal mode, the use of certain local storage options
+#     does not block the migration, but the user must not modify the
+#     contents of 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.
+#     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.
+#     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 memory must persist across the
+#     reboot, such as by backing it with a dax device.
 #
-#     cpr-reboot may not be used with postcopy, colo, or background-snapshot.
+#     @cpr-reboot may not be used with postcopy, background-snapshot,
+#     or COLO.
 #
 #     (since 8.2)
 ##