Re: [PATCH v5 07/21] acpi/ghes: Use HEST table offsets when preparing GHES records

[Igor Mammedov <imammedo@redhat.com>]

On Thu, 27 Feb 2025 12:03:37 +0100
Mauro Carvalho Chehab <mchehab+huawei@kernel.org> wrote:

> There are two pointers that are needed during error injection:
> 
> 1. The start address of the CPER block to be stored;
> 2. The address of the read ack.
> 
> It is preferable to calculate them from the HEST table.  This allows
> checking the source ID, the size of the table and the type of the
> HEST error block structures.
> 
> Yet, keep the old code, as this is needed for migration purposes
> from older QEMU versions.
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

Reviewed-by: Igor Mammedov <imammedo@redhat.com>

> ---
>  hw/acpi/ghes.c         | 100 +++++++++++++++++++++++++++++++++++++++++
>  include/hw/acpi/ghes.h |   2 +-
>  2 files changed, 101 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/acpi/ghes.c b/hw/acpi/ghes.c
> index 8ec423726b3f..5158418f93cb 100644
> --- a/hw/acpi/ghes.c
> +++ b/hw/acpi/ghes.c
> @@ -41,6 +41,12 @@
>  /* Address offset in Generic Address Structure(GAS) */
>  #define GAS_ADDR_OFFSET 4
>  
> +/*
> + * ACPI spec 1.0b
> + * 5.2.3 System Description Table Header
> + */
> +#define ACPI_DESC_HEADER_OFFSET     36
> +
>  /*
>   * The total size of Generic Error Data Entry
>   * ACPI 6.1/6.2: 18.3.2.7.1 Generic Error Data,
> @@ -61,6 +67,30 @@
>   */
>  #define ACPI_GHES_GESB_SIZE                 20
>  
> +/*
> + * See the memory layout map at docs/specs/acpi_hest_ghes.rst.
> + */
> +
> +/*
> + * ACPI 6.1: 18.3.2.8 Generic Hardware Error Source version 2
> + * Table 18-344 Generic Hardware Error Source version 2 (GHESv2) Structure
> + */
> +#define HEST_GHES_V2_ENTRY_SIZE  92
> +
> +/*
> + * ACPI 6.1: 18.3.2.8 Generic Hardware Error Source version 2
> + * Table 18-344 Generic Hardware Error Source version 2 (GHESv2) Structure
> + * Read Ack Register
> + */
> +#define GHES_READ_ACK_ADDR_OFF          64
> +
> +/*
> + * ACPI 6.1: 18.3.2.7: Generic Hardware Error Source
> + * Table 18-341 Generic Hardware Error Source Structure
> + * Error Status Address
> + */
> +#define GHES_ERR_STATUS_ADDR_OFF  20
> +
>  /*
>   * Values for error_severity field
>   */
> @@ -408,6 +438,73 @@ static void get_hw_error_offsets(uint64_t ghes_addr,
>      *read_ack_register_addr = ghes_addr + sizeof(uint64_t);
>  }
>  
> +static void get_ghes_source_offsets(uint16_t source_id,
> +                                    uint64_t hest_addr,
> +                                    uint64_t *cper_addr,
> +                                    uint64_t *read_ack_start_addr,
> +                                    Error **errp)
> +{
> +    uint64_t hest_err_block_addr, hest_read_ack_addr;
> +    uint64_t err_source_entry, error_block_addr;
> +    uint32_t num_sources, i;
> +
> +    hest_addr += ACPI_DESC_HEADER_OFFSET;
> +
> +    cpu_physical_memory_read(hest_addr, &num_sources,
> +                             sizeof(num_sources));
> +    num_sources = le32_to_cpu(num_sources);
> +
> +    err_source_entry = hest_addr + sizeof(num_sources);
> +
> +    /*
> +     * Currently, HEST Error source navigates only for GHESv2 tables
> +     */
> +    for (i = 0; i < num_sources; i++) {
> +        uint64_t addr = err_source_entry;
> +        uint16_t type, src_id;
> +
> +        cpu_physical_memory_read(addr, &type, sizeof(type));
> +        type = le16_to_cpu(type);
> +
> +        /* For now, we only know the size of GHESv2 table */
> +        if (type != ACPI_GHES_SOURCE_GENERIC_ERROR_V2) {
> +            error_setg(errp, "HEST: type %d not supported.", type);
> +            return;
> +        }
> +
> +        /* Compare CPER source ID at the GHESv2 structure */
> +        addr += sizeof(type);
> +        cpu_physical_memory_read(addr, &src_id, sizeof(src_id));
> +        if (le16_to_cpu(src_id) == source_id) {
> +            break;
> +        }
> +
> +        err_source_entry += HEST_GHES_V2_ENTRY_SIZE;
> +    }
> +    if (i == num_sources) {
> +        error_setg(errp, "HEST: Source %d not found.", source_id);
> +        return;
> +    }
> +
> +    /* Navigate through table address pointers */
> +    hest_err_block_addr = err_source_entry + GHES_ERR_STATUS_ADDR_OFF +
> +                          GAS_ADDR_OFFSET;
> +
> +    cpu_physical_memory_read(hest_err_block_addr, &error_block_addr,
> +                             sizeof(error_block_addr));
> +    error_block_addr = le64_to_cpu(error_block_addr);
> +
> +    cpu_physical_memory_read(error_block_addr, cper_addr,
> +                             sizeof(*cper_addr));
> +    *cper_addr = le64_to_cpu(*cper_addr);
> +
> +    hest_read_ack_addr = err_source_entry + GHES_READ_ACK_ADDR_OFF +
> +                         GAS_ADDR_OFFSET;
> +    cpu_physical_memory_read(hest_read_ack_addr, read_ack_start_addr,
> +                             sizeof(*read_ack_start_addr));
> +    *read_ack_start_addr = le64_to_cpu(*read_ack_start_addr);
> +}
> +
>  void ghes_record_cper_errors(AcpiGhesState *ags, const void *cper, size_t len,
>                               uint16_t source_id, Error **errp)
>  {
> @@ -423,6 +520,9 @@ void ghes_record_cper_errors(AcpiGhesState *ags, const void *cper, size_t len,
>      if (!ags->use_hest_addr) {
>          get_hw_error_offsets(le64_to_cpu(ags->hw_error_le),
>                               &cper_addr, &read_ack_register_addr);
> +    } else {
> +        get_ghes_source_offsets(source_id, le64_to_cpu(ags->hest_addr_le),
> +                                &cper_addr, &read_ack_register_addr, errp);
>      }
>  
>      cpu_physical_memory_read(read_ack_register_addr,
> diff --git a/include/hw/acpi/ghes.h b/include/hw/acpi/ghes.h
> index 38abe6e3db52..dcc7288ffba5 100644
> --- a/include/hw/acpi/ghes.h
> +++ b/include/hw/acpi/ghes.h
> @@ -79,7 +79,7 @@ enum {
>  typedef struct AcpiGhesState {
>      uint64_t hest_addr_le;
>      uint64_t hw_error_le;
> -    bool use_hest_addr;         /* Currently, always false */
> +    bool use_hest_addr; /* True if HEST address is present */
>  } AcpiGhesState;
>  
>  void acpi_build_hest(AcpiGhesState *ags, GArray *table_data,