Re: [PATCH v3 26/35] acpi: build_dsdt_microvm: use acpi_table_begin()/acpi_table_end() instead of build_header()

[Eric Auger]

On 9/7/21 4:48 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.
> 
> Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>

Eric
> ---
> v3:
>   * s/acpi_init_table|acpi_table_composed/acpi_table_begin|acpi_table_end/
> 
> CC: marcel.apfelbaum@gmail.com
> CC: kraxel@redhat.com
> ---
>  hw/i386/acpi-microvm.c | 13 ++++++-------
>  1 file changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/hw/i386/acpi-microvm.c b/hw/i386/acpi-microvm.c
> index 1a0f77b911..196d318499 100644
> --- a/hw/i386/acpi-microvm.c
> +++ b/hw/i386/acpi-microvm.c
> @@ -113,16 +113,16 @@ build_dsdt_microvm(GArray *table_data, BIOSLinker 
> *linker,
>      Aml *dsdt, *sb_scope, *scope, *pkg;
>      bool ambiguous;
>      Object *isabus;
> +    AcpiTable table = { .sig = "DSDT", .rev = 2, .oem_id = x86ms->oem_id,
> +                        .oem_table_id = x86ms->oem_table_id };
>  
>      isabus = object_resolve_path_type("", TYPE_ISA_BUS, &ambiguous);
>      assert(isabus);
>      assert(!ambiguous);
>  
> +    acpi_table_begin(&table, table_data);
>      dsdt = init_aml_allocator();
>  
> -    /* Reserve space for header */
> -    acpi_data_push(dsdt->buf, sizeof(AcpiTableHeader));
> -
>      sb_scope = aml_scope("_SB");
>      fw_cfg_add_acpi_dsdt(sb_scope, x86ms->fw_cfg);
>      isa_build_aml(ISA_BUS(isabus), sb_scope);
> @@ -144,11 +144,10 @@ build_dsdt_microvm(GArray *table_data, BIOSLinker 
> *linker,
>      aml_append(scope, aml_name_decl("_S5", pkg));
>      aml_append(dsdt, scope);
>  
> -    /* copy AML table into ACPI tables blob and patch header there */
> +    /* copy AML bytecode into ACPI tables blob */
>      g_array_append_vals(table_data, dsdt->buf->data, dsdt->buf->len);
> -    build_header(linker, table_data,
> -        (void *)(table_data->data + table_data->len - dsdt->buf->len),
> -                 "DSDT", dsdt->buf->len, 2, x86ms->oem_id, 
> x86ms->oem_table_id);
> +
> +    acpi_table_end(linker, &table);
>      free_aml_allocator();
>  }
>  
>