Re: [Qemu-devel] [RFC PATCH v2 09/11] hw/arm/virt-acpi-build: Generate XSDT table

[Igor Mammedov]

On Thu, 29 Jan 2015 16:37:11 +0800
Shannon Zhao <address@hidden> wrote:

> XDST points to other tables except FACS & DSDT.
Is there any reason to use XSDT instead of RSDT?
If ACPI tables are below 4Gb which probably would
be the case then RSDT could be used just fine and
we could share more code between x86 and ARM.

Laszlo,
Do you know if OVMF allocates memory below 4G address range?

> 
> Signed-off-by: Shannon Zhao <address@hidden>
> ---
>  hw/arm/virt-acpi-build.c    |   32 +++++++++++++++++++++++++++++++-
>  include/hw/acpi/acpi-defs.h |    9 +++++++++
>  2 files changed, 40 insertions(+), 1 deletions(-)
> 
> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c
> index ac0a864..2a2b2ab 100644
> --- a/hw/arm/virt-acpi-build.c
> +++ b/hw/arm/virt-acpi-build.c
> @@ -176,6 +176,32 @@ static void acpi_dsdt_add_virtio(AcpiAml *scope, const 
> hwaddr *mmio_addrs,
>      }
>  }
>  
> +
> +/* XSDT */
> +static void
> +build_xsdt(GArray *table_data, GArray *linker, GArray *table_offsets)
> +{
> +    AcpiXsdtDescriptor *xsdt;
> +    size_t xsdt_len;
> +    int i;
> +
> +    xsdt_len = sizeof(*xsdt) + sizeof(uint64_t) * table_offsets->len;
> +    xsdt = acpi_data_push(table_data, xsdt_len);
> +    memcpy(xsdt->table_offset_entry, table_offsets->data,
> +           sizeof(uint64_t) * table_offsets->len);
> +    for (i = 0; i < table_offsets->len; ++i) {
> +        /* xsdt->table_offset_entry to be filled by Guest linker */
> +        bios_linker_loader_add_pointer(linker,
> +                                       ACPI_BUILD_TABLE_FILE,
> +                                       ACPI_BUILD_TABLE_FILE,
> +                                       table_data, 
> &xsdt->table_offset_entry[i],
> +                                       sizeof(uint64_t));
> +    }
> +    build_header(linker, table_data, (void *)xsdt, "XSDT",
> +                 ACPI_BUILD_APPNAME6, ACPI_BUILD_APPNAME4,
> +                 xsdt_len, 1);
> +}
> +
>  /* GTDT */
>  static void
>  build_gtdt(GArray *table_data, GArray *linker, VirtGuestInfo *guest_info)
> @@ -311,7 +337,7 @@ static
>  void virt_acpi_build(VirtGuestInfo *guest_info, AcpiBuildTables *tables)
>  {
>      GArray *table_offsets;
> -    unsigned dsdt;
> +    unsigned dsdt, xsdt;
>      VirtAcpiCpuInfo cpuinfo;
>  
>      virt_acpi_get_cpu_info(&cpuinfo);
> @@ -346,6 +372,10 @@ void virt_acpi_build(VirtGuestInfo *guest_info, 
> AcpiBuildTables *tables)
>      acpi_add_table(table_offsets, tables->table_data.buf);
>      build_gtdt(tables->table_data.buf, tables->linker, guest_info);
>  
> +    /* XSDT is pointed to by RSDP */
> +    xsdt = tables->table_data.buf->len;
> +    build_xsdt(tables->table_data.buf, tables->linker, table_offsets);
> +
>      /* Cleanup memory that's no longer used. */
>      g_array_free(table_offsets, true);
>  }
> diff --git a/include/hw/acpi/acpi-defs.h b/include/hw/acpi/acpi-defs.h
> index ee40a5e..47c8c41 100644
> --- a/include/hw/acpi/acpi-defs.h
> +++ b/include/hw/acpi/acpi-defs.h
> @@ -88,6 +88,15 @@ struct AcpiTableHeader         /* ACPI common table header 
> */
>  typedef struct AcpiTableHeader AcpiTableHeader;
>  
>  /*
> + * Extended System Description Table (XSDT)
> + */
> +struct AcpiXsdtDescriptor {
> +    ACPI_TABLE_HEADER_DEF
> +    uint64_t table_offset_entry[1]; /* Array of pointers to ACPI tables */
> +} QEMU_PACKED;
> +typedef struct AcpiXsdtDescriptor AcpiXsdtDescriptor;
> +
> +/*
>   * ACPI Fixed ACPI Description Table (FADT)
>   */
>  #define ACPI_FADT_COMMON_DEF         /* FADT common definition */ \