Re: [RFC PATCH v2 01/10] x86/virt/tdx: Add a helper to read a table of metadata fields

[Binbin Wu]

On 9/18/2026 9:29 PM, Chao Gao wrote:
>  
> +/*
> + * Map a TDX global metadata field to a structure member.
> + * @field_id: The TDX global metadata field ID.
> + * @size: The size of the structure member.
> + * @offset: The member's offset within its containing structure.
> + */
> +struct field_mapping {
> +	u64 field_id;
> +	size_t size;
> +	int offset;

Nit:
Is it better to align the type of "size" and "offset" with size_t?
Since it's already 24 bytes per entry on x86_64, there is no extra memory cost.

> +};
> +
> +/* Read each metadata field listed in @mappings[] into @data. */
> +static int __maybe_unused __read_sys_metadata_table(const struct field_mapping *mappings,
> +						    int num_mappings, void *data)
> +{
> +	int i, ret;
> +	u64 val;
> +
> +	for (i = 0; i < num_mappings; i++) {
> +		ret = read_sys_metadata_field(mappings[i].field_id, &val);
> +		if (ret)
> +			return ret;
> +		memcpy((char *)data + mappings[i].offset, &val, mappings[i].size);
> +	}
> +
> +	return 0;
> +}
> +
> +#define TDX_SYSINFO_MAP(_field, _type, _member)			\
> +{								\
> +	.field_id	= TDX_MD_FIELD_ID_##_field,		\
> +	.offset		= offsetof(_type, _member),		\
> +	.size		= sizeof_field(_type, _member),		\
> +}
> +
>  #include "tdx_global_metadata.c"
>  
>  static __init int check_features(struct tdx_sys_info *sysinfo)