Re: [PATCH v2] hpet: do not overwrite properties on post_load

[Zhao Liu <zhao1.liu@intel.com>]

> @@ -347,14 +330,13 @@ static const VMStateDescription vmstate_hpet = {
>      .version_id = 2,
>      .minimum_version_id = 1,
>      .pre_save = hpet_pre_save,
> -    .pre_load = hpet_pre_load,
>      .post_load = hpet_post_load,
>      .fields = (const VMStateField[]) {
>          VMSTATE_UINT64(config, HPETState),
>          VMSTATE_UINT64(isr, HPETState),
>          VMSTATE_UINT64(hpet_counter, HPETState),
> -        VMSTATE_UINT8_V(num_timers, HPETState, 2),
> -        VMSTATE_VALIDATE("num_timers in range", hpet_validate_num_timers),
> +        VMSTATE_UINT8_V(num_timers_save, HPETState, 2),

This change is safe since it doesn't change the vmstate layout so that
there's no need for bumping up the version.

But I still have the question as the comment in v1 [*]. User doesn't
have any way to modify the number of timers, why not just replace this
vmstate field with "VMSTATE_UNUSED_V(2, 1)"?

Or do you think we should keep the status quo for the future use, even
if these properties have not been modified yet?

[*]: https://lore.kernel.org/qemu-devel/Z5Oq4LppNuN7N6NL@intel.com/

> +        VMSTATE_VALIDATE("num_timers must match", hpet_validate_num_timers),
>          VMSTATE_STRUCT_VARRAY_UINT8(timer, HPETState, num_timers, 0,
>                                      vmstate_hpet_timer, HPETTimer),
>          VMSTATE_END_OF_LIST()
> -- 
> 2.48.1
> 
>