Re: [PATCH V2 04/11] migration: stop vm earlier for cpr

[Fabiano Rosas <farosas@suse.de>]

Steve Sistare <steven.sistare@oracle.com> writes:

> Stop the vm earlier for cpr, to guarantee consistent device state when
> CPR state is saved.
>
> Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
> ---
>  migration/migration.c | 22 +++++++++++++---------
>  1 file changed, 13 insertions(+), 9 deletions(-)
>
> diff --git a/migration/migration.c b/migration/migration.c
> index 0f47765..8a8e927 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -2077,6 +2077,7 @@ void qmp_migrate(const char *uri, bool has_channels,
>      MigrationState *s = migrate_get_current();
>      g_autoptr(MigrationChannel) channel = NULL;
>      MigrationAddress *addr = NULL;
> +    bool stopped = false;
>  
>      /*
>       * Having preliminary checks for uri and channel
> @@ -2120,6 +2121,15 @@ void qmp_migrate(const char *uri, bool has_channels,
>          }
>      }
>  
> +    if (migrate_mode_is_cpr(s)) {
> +        int ret = migration_stop_vm(s, RUN_STATE_FINISH_MIGRATE);
> +        if (ret < 0) {
> +            error_setg(&local_err, "migration_stop_vm failed, error %d", -ret);
> +            goto out;
> +        }
> +        stopped = true;
> +    }
> +
>      if (cpr_state_save(&local_err)) {
>          goto out;
>      }
> @@ -2155,6 +2165,9 @@ out:
>          }
>          migrate_fd_error(s, local_err);
>          error_propagate(errp, local_err);
> +        if (stopped && runstate_is_live(s->vm_old_state)) {
> +            vm_start();
> +        }

What about non-live states? Shouldn't this be:

if (stopped) {
   vm_resume();
}

>          return;
>      }
>  }
> @@ -3738,7 +3751,6 @@ void migrate_fd_connect(MigrationState *s, Error *error_in)
>      Error *local_err = NULL;
>      uint64_t rate_limit;
>      bool resume = (s->state == MIGRATION_STATUS_POSTCOPY_RECOVER_SETUP);
> -    int ret;
>  
>      /*
>       * If there's a previous error, free it and prepare for another one.
> @@ -3810,14 +3822,6 @@ void migrate_fd_connect(MigrationState *s, Error *error_in)
>          return;
>      }
>  
> -    if (migrate_mode_is_cpr(s)) {
> -        ret = migration_stop_vm(s, RUN_STATE_FINISH_MIGRATE);
> -        if (ret < 0) {
> -            error_setg(&local_err, "migration_stop_vm failed, error %d", -ret);
> -            goto fail;
> -        }
> -    }
> -
>      if (migrate_background_snapshot()) {
>          qemu_thread_create(&s->thread, "mig/snapshot",
>                  bg_migration_thread, s, QEMU_THREAD_JOINABLE);