Re: [PATCH v5 03/16] migration: Run final save_query_pending at switchover

["Jason J. Herne" <jjherne@linux.ibm.com>]

On 7/6/26 4:51 AM, Avihai Horon wrote:
> Before switchover, the source needs one last exact pending query so
> modules can flush dirty state. This is currently done ad hoc in modules
> handlers. For example, RAM syncs its dirty bitmap in its save_complete
> handler.
> 
> This should be a general concept relevant for any module, so extract it
> to migration core instead by running a final save_query_pending before
> switchover.
> 
> The final query requires special handling by modules (e.g., it's called
> with BQL locked, during VM stop), so extend save_query_pending
> SaveVMHandlers callback and qemu_savevm_query_pending() with a "final"
> flag so migration modules can tell the last pending query during
> switchover from periodic iteration queries.
> 
> Call final pending query also in COLO checkpoint, which needs to flush
> dirty state before the checkpoint's live state is saved. Unlike a
> regular switchover, COLO reaches completion repeatedly for every
> checkpoint, so this must be done on each one.
> 
> Signed-off-by: Avihai Horon <avihaih@nvidia.com>
> ---
>   include/migration/register.h   | 41 ++++++++++++++++++----------------
>   migration/savevm.h             |  3 ++-
>   hw/s390x/s390-stattrib.c       |  2 +-
>   hw/vfio/migration.c            | 11 ++++++---
>   migration/block-dirty-bitmap.c | 11 ++++++---
>   migration/colo.c               | 10 +++++++++
>   migration/migration.c          | 14 ++++++++++--
>   migration/ram.c                | 40 +++++++++++++++++++--------------
>   migration/savevm.c             | 20 +++++++++++++----
>   hw/vfio/trace-events           |  2 +-
>   migration/trace-events         |  2 +-
>   11 files changed, 104 insertions(+), 52 deletions(-)

For the s390 piece...

Reviewed-by: Jason J. Herne <jjherne@linux.ibm.com>