Re: [PATCH v15 11/12] hmat acpi: Build Memory Side Cache Information Structure(s)

[Igor Mammedov <imammedo@redhat.com>]

[...]
> +/* ACPI 6.3: 5.2.27.5 Memory Side Cache Information Structure: Table 5-147 */
> +static void build_hmat_cache(GArray *table_data, HMAT_Cache_Info *hmat_cache)
> +{
> +    /*
> +     * Cache Attributes: Bits [3:0] – Total Cache Levels
> +     * for this Memory Proximity Domain
> +     */
> +    uint32_t cache_attr = hmat_cache->total_levels & 0xF;
applies to this and below maskings:
instead of masking add asserts with masks so API would explode instead
of silently ignoring invalid values.
If values are provided by user and graceful error handling is desired
make checks at CLI parsing time.

> +
> +    /* Bits [7:4] : Cache Level described in this structure */
> +    cache_attr |= (hmat_cache->level & 0xF) << 4;
> +
> +    /* Bits [11:8] - Cache Associativity */
> +    cache_attr |= (hmat_cache->associativity & 0x7) << 8;
> +
> +    /* Bits [15:12] - Write Policy */
> +    cache_attr |= (hmat_cache->write_policy & 0x7) << 12;
> +
> +    /* Bits [31:16] - Cache Line size in bytes */
> +    cache_attr |= (hmat_cache->line_size & 0xFFFF) << 16;

Would (unit16_t) field be promoted to uint32_t before it's shifted (according to C standard)
or we are just discarding value here?

> +    cache_attr = cpu_to_le32(cache_attr);
drop it,
build_append_int_noprefix() takes value in host byte order

> +
> +    /* Type */
> +    build_append_int_noprefix(table_data, 2, 2);
> +    /* Reserved */
> +    build_append_int_noprefix(table_data, 0, 2);
> +    /* Length */
> +    build_append_int_noprefix(table_data, 32, 4);
> +    /* Proximity Domain for the Memory */
> +    build_append_int_noprefix(table_data, hmat_cache->proximity, 4);
> +    /* Reserved */
> +    build_append_int_noprefix(table_data, 0, 4);
> +    /* Memory Side Cache Size */
> +    build_append_int_noprefix(table_data, hmat_cache->size, 8);
> +    /* Cache Attributes */
> +    build_append_int_noprefix(table_data, cache_attr, 4);
> +    /* Reserved */
> +    build_append_int_noprefix(table_data, 0, 2);
> +    /*
> +     * Number of SMBIOS handles (n)
> +     * Linux kernel uses Memory Side Cache Information Structure
> +     * without SMBIOS entries for now, so set Number of SMBIOS handles
> +     * as 0.
> +     */
> +    build_append_int_noprefix(table_data, 0, 2);
> +}
> +
>  /* Build HMAT sub table structures */
>  static void hmat_build_table_structs(GArray *table_data, NumaState *numa_state)
>  {
>      uint16_t flags;
>      uint32_t num_initiator = 0;
>      uint32_t initiator_list[MAX_NODES];
> -    int i, hierarchy, type;
> +    int i, hierarchy, type, cache_level, total_levels;
>      HMAT_LB_Info *hmat_lb;
> +    HMAT_Cache_Info *hmat_cache;
>  
>      for (i = 0; i < numa_state->num_nodes; i++) {
>          flags = 0;
> @@ -176,6 +225,27 @@ static void hmat_build_table_structs(GArray *table_data, NumaState *numa_state)
>              }
>          }
>      }
> +
> +    /*
> +     * ACPI 6.3: 5.2.27.5 Memory Side Cache Information Structure:
> +     * Table 5-147
> +     */
> +    for (i = 0; i < numa_state->num_nodes; i++) {
> +        total_levels = 0;
> +        for (cache_level = 1; cache_level <= MAX_HMAT_CACHE_LEVEL;
> +             cache_level++) {
> +            if (numa_state->hmat_cache[i][cache_level]) {
> +                total_levels++;
> +            }
> +        }
> +        for (cache_level = 0; cache_level <= total_levels; cache_level++) {
> +            hmat_cache = numa_state->hmat_cache[i][cache_level];
> +            if (hmat_cache) {
> +                hmat_cache->total_levels = total_levels;
pass total_levels as additional argument so you wouldn't need custom structure
(see my comment on 8/12)

> +                build_hmat_cache(table_data, hmat_cache);
> +            }
> +        }
> +    }
>  }
>  
>  void build_hmat(GArray *table_data, BIOSLinker *linker, NumaState *numa_state)