Re: [Qemu-devel] [PATCH 3/6] nvdimm acpi: introduce patched dsm memory

[Igor Mammedov <imammedo@redhat.com>]

On Tue,  5 Jan 2016 02:52:05 +0800
Xiao Guangrong <guangrong.xiao@linux.intel.com> wrote:

> The dsm memory is used to save the input parameters and store
> the dsm result which is filled by QEMU.
> 
> The address of dsm memory is decided by bios and patched into
> int64 object returned by "MEMA" method
> 
> Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
> ---
>  hw/acpi/aml-build.c         | 12 ++++++++++++
>  hw/acpi/nvdimm.c            | 24 ++++++++++++++++++++++--
>  include/hw/acpi/aml-build.h |  1 +
>  3 files changed, 35 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/acpi/aml-build.c b/hw/acpi/aml-build.c
> index 78e1290..83eadb3 100644
> --- a/hw/acpi/aml-build.c
> +++ b/hw/acpi/aml-build.c
> @@ -394,6 +394,18 @@ Aml *aml_int(const uint64_t val)
>  }
>  
>  /*
> + * ACPI 1.0b: 16.2.3 Data Objects Encoding:
> + * encode: QWordConst
> + */
> +Aml *aml_int64(const uint64_t val)
> +{
> +    Aml *var = aml_alloc();
> +    build_append_byte(var->buf, 0x0E); /* QWordPrefix */
> +    build_append_int_noprefix(var->buf, val, 8);
> +    return var;
> +}
> +
> +/*
>   * helper to construct NameString, which returns Aml object
>   * for using with aml_append or other aml_* terms
>   */
> diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
> index bc7cd8f..a72104c 100644
> --- a/hw/acpi/nvdimm.c
> +++ b/hw/acpi/nvdimm.c
> @@ -28,6 +28,7 @@
>  
>  #include "hw/acpi/acpi.h"
>  #include "hw/acpi/aml-build.h"
> +#include "hw/acpi/bios-linker-loader.h"
>  #include "hw/nvram/fw_cfg.h"
>  #include "hw/mem/nvdimm.h"
>  
> @@ -402,7 +403,8 @@ void nvdimm_init_acpi_state(AcpiNVDIMMState *state, MemoryRegion *io,
>                      state->dsm_mem->len);
>  }
>  
> -#define NVDIMM_COMMON_DSM      "NCAL"
> +#define NVDIMM_GET_DSM_MEM      "MEMA"
> +#define NVDIMM_COMMON_DSM       "NCAL"
>  
>  static void nvdimm_build_common_dsm(Aml *dev)
>  {
> @@ -468,7 +470,8 @@ static void nvdimm_build_ssdt(GSList *device_list, GArray *table_offsets,
>                                GArray *table_data, GArray *linker,
>                                uint8_t revision)
>  {
> -    Aml *ssdt, *sb_scope, *dev;
> +    Aml *ssdt, *sb_scope, *dev, *method;
> +    int offset;
>  
>      acpi_add_table(table_offsets, table_data);
>  
> @@ -499,9 +502,26 @@ static void nvdimm_build_ssdt(GSList *device_list, GArray *table_offsets,
>  
>      aml_append(sb_scope, dev);
>  
> +    /*
> +     * leave it at the end of ssdt so that we can conveniently get the
> +     * offset of int64 object returned by the function which will be
> +     * patched with the real address of the dsm memory by BIOS.
> +     */
> +    method = aml_method(NVDIMM_GET_DSM_MEM, 0, AML_NOTSERIALIZED);
> +    aml_append(method, aml_return(aml_int64(0x0)));
there is no need in dedicated aml_int64(), you can use aml_int(0x6400000000) trick

> +    aml_append(sb_scope, method);
>      aml_append(ssdt, sb_scope);
>      /* copy AML table into ACPI tables blob and patch header there */
>      g_array_append_vals(table_data, ssdt->buf->data, ssdt->buf->len);
> +
> +    offset = table_data->len - 8;
> +
> +    bios_linker_loader_alloc(linker, NVDIMM_DSM_MEM_FILE, TARGET_PAGE_SIZE,
> +                             false /* high memory */);
> +    bios_linker_loader_add_pointer(linker, ACPI_BUILD_TABLE_FILE,
> +                                   NVDIMM_DSM_MEM_FILE, table_data,
> +                                   table_data->data + offset,
> +                                   sizeof(uint64_t));
this offset magic will break badly as soon as someone add something
to the end of SSDT.


>      build_header(linker, table_data,
>          (void *)(table_data->data + table_data->len - ssdt->buf->len),
>          "SSDT", ssdt->buf->len, revision, "NVDIMM");
> diff --git a/include/hw/acpi/aml-build.h b/include/hw/acpi/aml-build.h
> index ef44d02..b4726a4 100644
> --- a/include/hw/acpi/aml-build.h
> +++ b/include/hw/acpi/aml-build.h
> @@ -246,6 +246,7 @@ Aml *aml_name(const char *name_format, ...) GCC_FMT_ATTR(1, 2);
>  Aml *aml_name_decl(const char *name, Aml *val);
>  Aml *aml_return(Aml *val);
>  Aml *aml_int(const uint64_t val);
> +Aml *aml_int64(const uint64_t val);
>  Aml *aml_arg(int pos);
>  Aml *aml_to_integer(Aml *arg);
>  Aml *aml_to_hexstring(Aml *src, Aml *dst);