Re: [Qemu-devel] [PATCH v4 4/7] hw/acpi: export default ACPI headers using the type just introduced

[Anthony Liguori <anthony@codemonkey.ws>]

Laszlo Ersek <lersek@redhat.com> writes:

> This enables reuse when preparing per-table fw_cfg blobs later.
>
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
> Acked-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>  include/hw/acpi/acpi.h |    2 ++
>  hw/acpi/core.c         |   39 ++++++++++++++++++++++++---------------
>  2 files changed, 26 insertions(+), 15 deletions(-)
>
> diff --git a/include/hw/acpi/acpi.h b/include/hw/acpi/acpi.h
> index 0e26f63..bc7e107 100644
> --- a/include/hw/acpi/acpi.h
> +++ b/include/hw/acpi/acpi.h
> @@ -178,4 +178,6 @@ typedef struct acpi_table_std_header {
>      char asl_compiler_id[4];  /* ASL compiler vendor ID */
>      uint32_t asl_compiler_revision; /* ASL compiler revision number */
>  } QEMU_PACKED AcpiTableStdHdr;
> +
> +extern const AcpiTableStdHdr acpi_dfl_hdr;

Can we do this without using a global variable?  I assume this gets
memcpy()'d or referenced as a pointer later on or something like that?
Can we make a function that does that?

Regards,

Anthony Liguori

>  #endif /* !QEMU_HW_ACPI_H */
> diff --git a/hw/acpi/core.c b/hw/acpi/core.c
> index d348f81..36a4d03 100644
> --- a/hw/acpi/core.c
> +++ b/hw/acpi/core.c
> @@ -37,11 +37,20 @@ struct acpi_table_header {
>  /* size of the extra prefix */
>  #define ACPI_TABLE_PFX_SIZE offsetof(struct acpi_table_header, std)
>  
> -static const char unsigned dfl_hdr[sizeof(AcpiTableStdHdr)] =
> -    "QEMU\0\0\0\0\1\0"       /* sig (4), len(4), revno (1), csum (1) */
> -    "QEMUQEQEMUQEMU\1\0\0\0" /* OEM id (6), table (8), revno (4) */
> -    "QEMU\1\0\0\0"           /* ASL compiler ID (4), version (4) */
> -    ;
> +const AcpiTableStdHdr acpi_dfl_hdr = {
> +    .sig = "QEMU",
> +    .revision = 1,
> +    .oem_id = "QEMUQE",
> +    .oem_table_id = "QEMUQEMU",
> +    .asl_compiler_id = "QEMU",
> +#ifdef HOST_WORDS_BIGENDIAN
> +    .oem_revision = 0x01000000,
> +    .asl_compiler_revision = 0x01000000
> +#else
> +    .oem_revision = 1,
> +    .asl_compiler_revision = 1
> +#endif
> +};
>  
>  char unsigned *acpi_tables;
>  size_t acpi_tables_len;
> @@ -74,8 +83,8 @@ static int acpi_checksum(const uint8_t *data, int len)
>  /* Install a copy of the ACPI table specified in @blob.
>   *
>   * If @has_header is set, @blob starts with the System Description Table Header
> - * structure. Otherwise, "dfl_hdr" is prepended. In any case, each header field
> - * is optionally overwritten from @hdrs.
> + * structure. Otherwise, "acpi_dfl_hdr" is prepended. In any case, each header
> + * field is optionally overwritten from @hdrs.
>   *
>   * It is valid to call this function with
>   * (@blob == NULL && @bloblen == 0 && !@has_header).
> @@ -105,13 +114,13 @@ static void acpi_table_install(const char unsigned *blob, size_t bloblen,
>      if (has_header) {
>          /*   _length             | ACPI header in blob | blob body
>           *   ^^^^^^^^^^^^^^^^^^^   ^^^^^^^^^^^^^^^^^^^   ^^^^^^^^^
> -         *   ACPI_TABLE_PFX_SIZE     sizeof dfl_hdr      body_size
> +         *   ACPI_TABLE_PFX_SIZE   sizeof acpi_dfl_hdr   body_size
>           *                           == body_start
>           *
>           *                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>           *                           acpi_payload_size == bloblen
>           */
> -        body_start = sizeof dfl_hdr;
> +        body_start = sizeof acpi_dfl_hdr;
>  
>          if (bloblen < body_start) {
>              error_setg(errp, "ACPI table claiming to have header is too "
> @@ -123,17 +132,17 @@ static void acpi_table_install(const char unsigned *blob, size_t bloblen,
>      } else {
>          /*   _length             | ACPI header in template | blob body
>           *   ^^^^^^^^^^^^^^^^^^^   ^^^^^^^^^^^^^^^^^^^^^^^   ^^^^^^^^^^
> -         *   ACPI_TABLE_PFX_SIZE       sizeof dfl_hdr        body_size
> +         *   ACPI_TABLE_PFX_SIZE     sizeof acpi_dfl_hdr     body_size
>           *                                                   == bloblen
>           *
>           *                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>           *                                  acpi_payload_size
>           */
>          body_start = 0;
> -        hdr_src = dfl_hdr;
> +        hdr_src = (const char unsigned *)&acpi_dfl_hdr;
>      }
>      body_size = bloblen - body_start;
> -    acpi_payload_size = sizeof dfl_hdr + body_size;
> +    acpi_payload_size = sizeof acpi_dfl_hdr + body_size;
>  
>      if (acpi_payload_size > UINT16_MAX) {
>          error_setg(errp, "ACPI table too big, requested: %zu, max: %u",
> @@ -149,13 +158,13 @@ static void acpi_table_install(const char unsigned *blob, size_t bloblen,
>  
>      acpi_tables = g_realloc(acpi_tables, acpi_tables_len +
>                                           ACPI_TABLE_PFX_SIZE +
> -                                         sizeof dfl_hdr + body_size);
> +                                         sizeof acpi_dfl_hdr + body_size);
>  
>      ext_hdr = (struct acpi_table_header *)(acpi_tables + acpi_tables_len);
>      acpi_tables_len += ACPI_TABLE_PFX_SIZE;
>  
> -    memcpy(acpi_tables + acpi_tables_len, hdr_src, sizeof dfl_hdr);
> -    acpi_tables_len += sizeof dfl_hdr;
> +    memcpy(acpi_tables + acpi_tables_len, hdr_src, sizeof acpi_dfl_hdr);
> +    acpi_tables_len += sizeof acpi_dfl_hdr;
>  
>      if (blob != NULL) {
>          memcpy(acpi_tables + acpi_tables_len, blob + body_start, body_size);
> -- 
> 1.7.1