On Fri, 3 Jul 2020 at 21:19, Philippe Mathieu-Daudé <f4...@amsat.org> wrote:
>
> Introduce a special state to indicate when an object doesn't
> have anything in its state to migrate.
>
> Suggested-by: Peter Maydell <peter.mayd...@linaro.org>
> Signed-off-by: Philippe Mathieu-Daudé <f4...@amsat.org>
> ---
> include/migration/vmstate.h | 1 +
> migration/vmstate.c | 7 +++++++
> 2 files changed, 8 insertions(+)
>
> diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h
> index af7d80cd4e..0922bc8efa 100644
> --- a/include/migration/vmstate.h
> +++ b/include/migration/vmstate.h
> @@ -195,6 +195,7 @@ struct VMStateDescription {
> };
>
> extern const VMStateDescription vmstate_dummy; /* Exclusively for linux-user
> */
> +extern const VMStateDescription vmstate_no_state_to_migrate;
>
> extern const VMStateInfo vmstate_info_bool;
>
> diff --git a/migration/vmstate.c b/migration/vmstate.c
> index bafa890384..d640cafad3 100644
> --- a/migration/vmstate.c
> +++ b/migration/vmstate.c
> @@ -20,6 +20,13 @@
> #include "trace.h"
> #include "qjson.h"
>
> +const VMStateDescription vmstate_no_state_to_migrate = {
> + .name = "empty-state",
> + .fields = (VMStateField[]) {
> + VMSTATE_END_OF_LIST()
> + }
> +};
Does this definitely not put any data into the migration stream?
We don't want to change what's on the wire for machines that
use devices that start using this. (If it does by default, it
would be easy to make the migration code special case the
magic symbol to act like "no vmsd specified").
thanks
-- PMM
