Re: [PATCH v3 09/35] acpi: build_hmat: use acpi_table_begin()/acpi_table_end() instead of build_header()

[Eric Auger]

Hi Igor,

On 9/7/21 4:47 PM, Igor Mammedov wrote:
> it replaces error-prone pointer arithmetic for build_header() API,
> with 2 calls to start and finish table creation,
> which hides offsets magic from API user.
> 
> Also since acpi_table_begin() reserves space only for standard header
> while previous acpi_data_push() reserved the header + 4 bytes field,
> add 4 bytes 'Reserved' field into hmat_build_table_structs()
> which didn have it.
> 
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>

Eruc
> ---
> v3:
>   * s/acpi_init_table|acpi_table_composed/acpi_table_begin|acpi_table_end/
> ---
>  hw/acpi/hmat.c | 14 ++++++--------
>  1 file changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/hw/acpi/hmat.c b/hw/acpi/hmat.c
> index edb3fd91b2..6913ebf730 100644
> --- a/hw/acpi/hmat.c
> +++ b/hw/acpi/hmat.c
> @@ -200,6 +200,8 @@ static void hmat_build_table_structs(GArray *table_data, 
> NumaState *numa_state)
>      HMAT_LB_Info *hmat_lb;
>      NumaHmatCacheOptions *hmat_cache;
>  
> +    build_append_int_noprefix(table_data, 0, 4); /* Reserved */
> +
>      for (i = 0; i < numa_state->num_nodes; i++) {
>          flags = 0;
>  
> @@ -256,14 +258,10 @@ static void hmat_build_table_structs(GArray 
> *table_data, NumaState *numa_state)
>  void build_hmat(GArray *table_data, BIOSLinker *linker, NumaState 
> *numa_state,
>                  const char *oem_id, const char *oem_table_id)
>  {
> -    int hmat_start = table_data->len;
> -
> -    /* reserve space for HMAT header  */
> -    acpi_data_push(table_data, 40);
> +    AcpiTable table = { .sig = "HMAT", .rev = 2,
> +                        .oem_id = oem_id, .oem_table_id = oem_table_id };
>  
> +    acpi_table_begin(&table, table_data);
>      hmat_build_table_structs(table_data, numa_state);
> -
> -    build_header(linker, table_data,
> -                 (void *)(table_data->data + hmat_start),
> -                 "HMAT", table_data->len - hmat_start, 2, oem_id, 
> oem_table_id);
> +    acpi_table_end(linker, &table);
>  }
>