[PATCH v9 00/19] migration: Add COLO multifd support and COLO migration unit test

[Lukas Straub <lukasstraub2@web.de>]

Hello everyone,
This has some cleanups for and adds multifd support and migration unit tests
for COLO migration.

Regards,
Lukas

Signed-off-by: Lukas Straub <lukasstraub2@web.de>
---
Changes in v9:
- Rebase onto master
- Fix two rare bugs discovered during sresstesting the colo unit test
- Link to v8: https://lore.kernel.org/qemu-devel/20260210-colo_unit_test_multifd-v8-0-7f9e5f7d082b@web.de

Changes in v8:
- Fix peter's review comments
- Link to v7: https://lore.kernel.org/qemu-devel/20260210-colo_unit_test_multifd-v7-0-23bd32f36828@web.de

Changes in v7:
- Fix peter's review comments
- Link to v6: https://lore.kernel.org/qemu-devel/20260206-colo_unit_test_multifd-v6-0-27779dda139d@web.de

Changes in v6:
- Fix the crash when running COLO with TCG accel.
- Link to v5: https://lore.kernel.org/qemu-devel/20260203-colo_unit_test_multifd-v5-0-57508b7389f6@web.de

Changes in v5:
- Remove unused inmports from multifd-colo.c
- Mention the checkpoint overhead of reset to the Q35 fix
- Link to v4: https://lore.kernel.org/qemu-devel/20260130-colo_unit_test_multifd-v4-0-7115ab6f0e77@web.de

Changes in v4:
- Add cleanup patches to remove migration_incoming_colo_enabled() and MIG_CMD_ENABLE_COLO
- Add more comments to the colo unit test
- Call colo_release_ram_cache() after multifd threads terminate
- Link to v3: https://lore.kernel.org/qemu-devel/20260125-colo_unit_test_multifd-v3-0-ae926ccd8eae@web.de

Changes in v3:
- Fix peter's review comments.
- Fix COLO with Q35 machine
- Link to v2: https://lore.kernel.org/qemu-devel/20260117-colo_unit_test_multifd-v2-0-ab521777fa51@web.de

Changes in v2:
- Fix review comments
- Hide stderr in colo migration test since the logged errors are expected
- Add benchmarking data for multifd
- Add myself as maintainer for COLO migration framework
- Link to v1: https://lore.kernel.org/qemu-devel/20251230-colo_unit_test_multifd-v1-0-f9734bc74c71@web.de

---
Lukas Straub (19):
      MAINTAINERS: Add myself as maintainer for COLO migration framework
      MAINTAINERS: Remove Hailiang Zhang from COLO migration framework
      colo: Setup ram cache in normal migration path
      colo: Replace migration_incoming_colo_enabled() with migrate_colo()
      colo: Remove ENABLE_COLO savevm command and mark it as deprecated
      ram: Remove colo special-casing
      multifd: Move ram state receive into multifd_ram_state_recv()
      multifd: Add COLO support
      Call colo_release_ram_cache() after multifd threads terminate
      colo: Fix crash during device vmstate load
      colo: Hold the BQL while sending ram state
      colo: Do not hold the BQL while receiving ram state.
      migration-test: Add COLO migration unit test
      Convert colo main documentation to restructuredText
      qemu-colo.rst: Miscellaneous changes
      qemu-colo.rst: Add my copyright
      qemu-colo.rst: Simplify the block replication setup
      multifd: Fix hang if send thread errors during sync
      colo: Fix a rare crash during shutdown

 MAINTAINERS                        |   6 +-
 docs/COLO-FT.txt                   | 334 ----------------------------------
 docs/system/index.rst              |   1 +
 docs/system/qemu-colo.rst          | 362 +++++++++++++++++++++++++++++++++++++
 include/migration/colo.h           |   3 -
 migration/colo.c                   |  44 +++--
 migration/meson.build              |   2 +-
 migration/migration.c              |  61 ++-----
 migration/multifd-colo.c           |  44 +++++
 migration/multifd-colo.h           |  26 +++
 migration/multifd-nocomp.c         |  10 +-
 migration/multifd.c                |  20 +-
 migration/multifd.h                |   5 +-
 migration/ram.c                    |  12 +-
 migration/savevm.c                 |  37 +---
 migration/savevm.h                 |   1 -
 migration/trace-events             |   1 -
 tests/qtest/meson.build            |   7 +-
 tests/qtest/migration-test.c       |   1 +
 tests/qtest/migration/colo-tests.c | 198 ++++++++++++++++++++
 tests/qtest/migration/framework.h  |   5 +
 21 files changed, 736 insertions(+), 444 deletions(-)
---
base-commit: 314f2d7fe601b8dba2a88ac4870469e9f6bb8464
change-id: 20251230-colo_unit_test_multifd-8bf58dcebd46

Best regards,
-- 
Lukas Straub <lukasstraub2@web.de>