Re: [Qemu-devel] [PATCH v7 07/19] migration: introduce icount field for snapshots

[Kevin Wolf <kwolf@redhat.com>]

Am 10.10.2018 um 15:34 hat Pavel Dovgalyuk geschrieben:
> Saving icount as a parameters of the snapshot allows navigation between
> them in the execution replay scenario.
> This information can be used for finding a specific snapshot for rewinding
> the recorded execution to the specific moment of the time.
> E.g., 'reverse step' action needs to load the nearest snapshot which is
> prior to the current moment of time .
> 
> Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>

> diff --git a/block/qapi.c b/block/qapi.c
> index c66f949..9f2ccfa 100644
> --- a/block/qapi.c
> +++ b/block/qapi.c
> @@ -210,6 +210,7 @@ int bdrv_query_snapshot_info_list(BlockDriverState *bs,
>          info->date_nsec     = sn_tab[i].date_nsec;
>          info->vm_clock_sec  = sn_tab[i].vm_clock_nsec / 1000000000;
>          info->vm_clock_nsec = sn_tab[i].vm_clock_nsec % 1000000000;
> +        info->icount        = sn_tab[i].icount;

Now that it's optional, info->has_icount needs to be set, too.

>          info_list = g_new0(SnapshotInfoList, 1);
>          info_list->value = info;

> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index cfb37f8..34dc9f1 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -26,13 +26,18 @@
>  #
>  # @vm-clock-nsec: fractional part in nano seconds to be used with vm-clock-sec
>  #
> +# @icount: Current instruction count. Appears when execution record/replay
> +#          is enabled. Used for "time-traveling" to match the moment
> +#          in the recorded execution with the snapshots (since 3.1)

"(since 4.0)" now.

Kevin