Re: [RFC PATCH 5/9] rust: vmstate: implement VMState for scalar types

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

>  #[macro_export]
>  macro_rules! vmstate_of {
> -    ($struct_name:ty, $field_name:ident $([0 .. $num:ident $(* $factor:expr)?])? $(,)?) => {
> +    ($struct_name:ty, $field_name:ident $([0 .. $num:tt $(* $factor:expr)?])? $(,)?) => {

Why change ident to tt? 

>          $crate::bindings::VMStateField {
>              name: ::core::concat!(::core::stringify!($field_name), "\0")
>                  .as_bytes()
> @@ -109,6 +197,11 @@ macro_rules! vmstate_of {
>              $(.num_offset: $crate::offset_of!($struct_name, $num),)?
>              // The calls to `call_func_with_field!` are the magic that
>              // computes most of the VMStateField from the type of the field.
> +            info: $crate::info_enum_to_ref!($crate::call_func_with_field!(
> +                $crate::vmstate::vmstate_scalar_type,
> +                $struct_name,
> +                $field_name
> +            )),
>              ..$crate::call_func_with_field!(
>                  $crate::vmstate::vmstate_base,
>                  $struct_name,

...

> +impl_vmstate_scalar!(vmstate_info_bool, bool);
> +impl_vmstate_scalar!(vmstate_info_int8, i8);
> +impl_vmstate_scalar!(vmstate_info_int16, i16);
> +impl_vmstate_scalar!(vmstate_info_int32, i32);

missed VMS_VARRAY_INT32 :-)

> +impl_vmstate_scalar!(vmstate_info_int64, i64);
> +impl_vmstate_scalar!(vmstate_info_uint8, u8, VMS_VARRAY_UINT8);
> +impl_vmstate_scalar!(vmstate_info_uint16, u16, VMS_VARRAY_UINT16);
> +impl_vmstate_scalar!(vmstate_info_uint32, u32, VMS_VARRAY_UINT32);

If we want to expand in the future (e.g., support vmstate_info_int32_equal
and vmstate_info_int32_le), then introducing new macro variants will be
straightforward. So, fair enough.

> +impl_vmstate_scalar!(vmstate_info_uint64, u64);

What about applying this to "usize" with vmstate_info_uint64?

For array length, I think usize is also used wildly. Maybe we can add
VMS_VARRAY_UINT64 and just treat usize as u64.

> +impl_vmstate_scalar!(vmstate_info_timer, bindings::QEMUTimer);
> +
>  // Pointer types using the underlying type's VMState plus VMS_POINTER
>  
>  macro_rules! impl_vmstate_pointer {
> -- 
> 2.47.1

Overall, I think it's good; the design idea is coherent.

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>