On Mon, Apr 29, 2024 at 08:55:14AM -0700, Steve Sistare wrote:
> Provide the VMStateDescription precreate field to mark objects that must
> be loaded on the incoming side before devices have been created, because
> they provide properties that will be needed at creation time. They will
> be saved to and loaded from their own QEMUFile, via
> qemu_savevm_precreate_save and qemu_savevm_precreate_load, but these
> functions are not yet called in this patch. Allow them to be called
> before or after normal migration is active, when current_migration and
> current_incoming are not valid.
>
> Signed-off-by: Steve Sistare <steven.sist...@oracle.com>
> ---
> include/migration/vmstate.h | 6 ++++
> migration/savevm.c | 69
> +++++++++++++++++++++++++++++++++++++++++----
> migration/savevm.h | 3 ++
> 3 files changed, 73 insertions(+), 5 deletions(-)
>
> diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
> index 294d2d8..4691334 100644
> --- a/include/migration/vmstate.h
> +++ b/include/migration/vmstate.h
> @@ -198,6 +198,12 @@ struct VMStateDescription {
> * a QEMU_VM_SECTION_START section.
> */
> bool early_setup;
> +
> + /*
> + * Send/receive this object in the precreate migration stream.
> + */
> + bool precreate;
> +
> int version_id;
> int minimum_version_id;
> MigrationPriority priority;
> diff --git a/migration/savevm.c b/migration/savevm.c
> index 9789823..a30bcd9 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -239,6 +239,7 @@ static SaveState savevm_state = {
>
> #define SAVEVM_FOREACH(se, entry) \
> QTAILQ_FOREACH(se, &savevm_state.handlers, entry) \
> + if (!se->vmsd || !se->vmsd->precreate)
>
> #define SAVEVM_FOREACH_ALL(se, entry) \
> QTAILQ_FOREACH(se, &savevm_state.handlers, entry)
> @@ -1006,13 +1007,19 @@ static void save_section_header(QEMUFile *f,
> SaveStateEntry *se,
> }
> }
>
> +static bool send_section_footer(SaveStateEntry *se)
> +{
> + return (se->vmsd && se->vmsd->precreate) ||
> + migrate_get_current()->send_section_footer;
> +}
Does the precreate vmsd "require" the footer? Or it should also work?
IMHO it's less optimal to bind features without good reasons.
Thanks,
--
Peter Xu
