Re: [Qemu-devel] [PATCH v2 02/18] i386/acpi-build: allow SSDT to operate on 64 bit

[Igor Mammedov <imammedo@redhat.com>]

On Fri, 14 Aug 2015 22:51:55 +0800
Xiao Guangrong <guangrong.xiao@linux.intel.com> wrote:

> Only 512M is left for MMIO below 4G and that are used by PCI, BIOS etc.
> Other components also reserve regions from their internal usage, e.g,
> [0xFED00000, 0xFED00000 + 0x400) is reserved for HPET
> 
> Switch SSDT to 64 bit to use the huge free room above 4G. In the later
> patches, we will dynamical allocate free space within this region which
> is used by NVDIMM _DSM method
> 
> Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
> ---
>  hw/i386/acpi-build.c  | 4 ++--
>  hw/i386/acpi-dsdt.dsl | 2 +-
>  2 files changed, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 46eddb8..8ead1c1 100644
> --- a/hw/i386/acpi-build.c
> +++ b/hw/i386/acpi-build.c
> @@ -1348,7 +1348,7 @@ build_ssdt(GArray *table_data, GArray *linker,
>      g_array_append_vals(table_data, ssdt->buf->data, ssdt->buf->len);
>      build_header(linker, table_data,
>          (void *)(table_data->data + table_data->len - ssdt->buf->len),
> -        "SSDT", ssdt->buf->len, 1);
> +        "SSDT", ssdt->buf->len, 2);
That might break Windows XP, since it supports only 1.0b ACPI with some
2.0 extensions.
there is 2 way to work around it:
 - add an additional Rev2 ssdt table if NVDIMMs are present
   and describe them there
 - make sure that you use only 32bit arithmetic in AML
   (and emulate 64bit like it has been done for memory hotplug)

>      free_aml_allocator();
>  }
>  
> @@ -1586,7 +1586,7 @@ build_dsdt(GArray *table_data, GArray *linker, AcpiMiscInfo *misc)
>  
>      memset(dsdt, 0, sizeof *dsdt);
>      build_header(linker, table_data, dsdt, "DSDT",
> -                 misc->dsdt_size, 1);
> +                 misc->dsdt_size, 2);
>  }
>  
>  static GArray *
> diff --git a/hw/i386/acpi-dsdt.dsl b/hw/i386/acpi-dsdt.dsl
> index a2d84ec..5cd3f0e 100644
> --- a/hw/i386/acpi-dsdt.dsl
> +++ b/hw/i386/acpi-dsdt.dsl
> @@ -22,7 +22,7 @@ ACPI_EXTRACT_ALL_CODE AcpiDsdtAmlCode
>  DefinitionBlock (
>      "acpi-dsdt.aml",    // Output Filename
>      "DSDT",             // Signature
> -    0x01,               // DSDT Compliance Revision
> +    0x02,               // DSDT Compliance Revision
>      "BXPC",             // OEMID
>      "BXDSDT",           // TABLE ID
>      0x1                 // OEM Revision