Re: [PATCH v3 10/35] acpi: nvdimm_build_nfit: use acpi_table_begin()/acpi_table_end() instead of build_header()

[Eric Auger]

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 nvdimm_build_nfit() which didn't
> have it.
> 
> 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: xiaoguangrong.eric@gmail.com
> ---
>  hw/acpi/nvdimm.c | 42 +++++++++++++++++-------------------------
>  1 file changed, 17 insertions(+), 25 deletions(-)
> 
> diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
> index e3d5fe1939..15f6ca82ca 100644
> --- a/hw/acpi/nvdimm.c
> +++ b/hw/acpi/nvdimm.c
> @@ -44,22 +44,6 @@ static const uint8_t nvdimm_nfit_spa_uuid[] =
>        UUID_LE(0x66f0d379, 0xb4f3, 0x4074, 0xac, 0x43, 0x0d, 0x33,
>                0x18, 0xb7, 0x8c, 0xdb);
>  
> -/*
> - * NVDIMM Firmware Interface Table
> - * @signature: "NFIT"
> - *
> - * It provides information that allows OSPM to enumerate NVDIMM present in
> - * the platform and associate system physical address ranges created by the
> - * NVDIMMs.
> - *
> - * It is defined in ACPI 6.0: 5.2.25 NVDIMM Firmware Interface Table (NFIT)
> - */
> -struct NvdimmNfitHeader {
> -    ACPI_TABLE_HEADER_DEF
> -    uint32_t reserved;
> -} QEMU_PACKED;
> -typedef struct NvdimmNfitHeader NvdimmNfitHeader;
> -
>  /*
>   * define NFIT structures according to ACPI 6.0: 5.2.25 NVDIMM Firmware
>   * Interface Table (NFIT).
> @@ -401,25 +385,33 @@ void nvdimm_plug(NVDIMMState *state)
>      nvdimm_build_fit_buffer(state);
>  }
>  
> +/*
> + * NVDIMM Firmware Interface Table
> + * @signature: "NFIT"
> + *
> + * It provides information that allows OSPM to enumerate NVDIMM present in
> + * the platform and associate system physical address ranges created by the
> + * NVDIMMs.
> + *
> + * It is defined in ACPI 6.0: 5.2.25 NVDIMM Firmware Interface Table (NFIT)
> + */
> +
>  static void nvdimm_build_nfit(NVDIMMState *state, GArray *table_offsets,
>                                GArray *table_data, BIOSLinker *linker,
>                                const char *oem_id, const char *oem_table_id)
>  {
>      NvdimmFitBuffer *fit_buf = &state->fit_buf;
> -    unsigned int header;
> +    AcpiTable table = { .sig = "NFIT", .rev = 1,
> +                        .oem_id = oem_id, .oem_table_id = oem_table_id };
>  
>      acpi_add_table(table_offsets, table_data);
>  
> -    /* NFIT header. */
> -    header = table_data->len;
> -    acpi_data_push(table_data, sizeof(NvdimmNfitHeader));
> +    acpi_table_begin(&table, table_data);
> +    /* Reserved */
> +    build_append_int_noprefix(table_data, 0, 4);
>      /* NVDIMM device structures. */
>      g_array_append_vals(table_data, fit_buf->fit->data, fit_buf->fit->len);
> -
> -    build_header(linker, table_data,
> -                 (void *)(table_data->data + header), "NFIT",
> -                 sizeof(NvdimmNfitHeader) + fit_buf->fit->len, 1, oem_id,
> -                 oem_table_id);
> +    acpi_table_end(linker, &table);
>  }
>  
>  #define NVDIMM_DSM_MEMORY_SIZE      4096
>