linux-kernel - Re: [PATCH v4 02/14] acpi/ghes: add a firmware file with HEST address

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Message-ID: <20250226154802.58d865a8@imammedo.users.ipa.redhat.com>
Date: Wed, 26 Feb 2025 15:48:02 +0100
From: Igor Mammedov <imammedo@...hat.com>
To: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
Cc: "Michael S . Tsirkin" <mst@...hat.com>, Jonathan Cameron
 <Jonathan.Cameron@...wei.com>, Shiju Jose <shiju.jose@...wei.com>,
 qemu-arm@...gnu.org, qemu-devel@...gnu.org, Ani Sinha
 <anisinha@...hat.com>, Dongjiu Geng <gengdongjiu1@...il.com>,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 02/14] acpi/ghes: add a firmware file with HEST
 address

On Fri, 21 Feb 2025 15:35:11 +0100
Mauro Carvalho Chehab <mchehab+huawei@...nel.org> wrote:

> Store HEST table address at GPA, placing its the start of the table at
> hest_addr_le variable.
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
> Reviewed-by: Igor Mammedov <imammedo@...hat.com>
> ---
>  hw/acpi/ghes.c         | 22 ++++++++++++++++++++--
>  include/hw/acpi/ghes.h |  7 ++++++-
>  2 files changed, 26 insertions(+), 3 deletions(-)
> 
> diff --git a/hw/acpi/ghes.c b/hw/acpi/ghes.c
> index e49a03fdb94e..ba37be9e7022 100644
> --- a/hw/acpi/ghes.c
> +++ b/hw/acpi/ghes.c
> @@ -30,6 +30,7 @@
>  
>  #define ACPI_HW_ERROR_FW_CFG_FILE           "etc/hardware_errors"
>  #define ACPI_HW_ERROR_ADDR_FW_CFG_FILE      "etc/hardware_errors_addr"
> +#define ACPI_HEST_ADDR_FW_CFG_FILE          "etc/acpi_table_hest_addr"
>  
>  /* The max size in bytes for one error block */
>  #define ACPI_GHES_MAX_RAW_DATA_LENGTH   (1 * KiB)
> @@ -341,6 +342,9 @@ void acpi_build_hest(AcpiGhesState *ags, GArray *table_data,
>  {
>      AcpiTable table = { .sig = "HEST", .rev = 1,
>                          .oem_id = oem_id, .oem_table_id = oem_table_id };
> +    uint32_t hest_offset;
> +
> +    hest_offset = table_data->len;
>  
>      build_ghes_error_table(ags, hardware_errors, linker);
>  
> @@ -352,6 +356,17 @@ void acpi_build_hest(AcpiGhesState *ags, GArray *table_data,
>                    ACPI_GHES_NOTIFY_SEA, ACPI_HEST_SRC_ID_SEA);
>  
>      acpi_table_end(linker, &table);
> +
> +    if (ags->use_hest_addr) {
> +        /*
> +         * Tell firmware to write into GPA the address of HEST via fw_cfg,
> +         * once initialized.
> +         */
> +        bios_linker_loader_write_pointer(linker,
> +                                         ACPI_HEST_ADDR_FW_CFG_FILE, 0,
> +                                         sizeof(uint64_t),
> +                                         ACPI_BUILD_TABLE_FILE, hest_offset);
> +    }
>  }
>  
>  void acpi_ghes_add_fw_cfg(AcpiGhesState *ags, FWCfgState *s,
> @@ -361,7 +376,10 @@ void acpi_ghes_add_fw_cfg(AcpiGhesState *ags, FWCfgState *s,
>      fw_cfg_add_file(s, ACPI_HW_ERROR_FW_CFG_FILE, hardware_error->data,
>                      hardware_error->len);
>  
> -    if (!ags->use_hest_addr) {
> +    if (ags->use_hest_addr) {
> +        fw_cfg_add_file_callback(s, ACPI_HEST_ADDR_FW_CFG_FILE, NULL, NULL,
> +            NULL, &(ags->hest_addr_le), sizeof(ags->hest_addr_le), false);
> +    } else {
>          /* Create a read-write fw_cfg file for Address */
>          fw_cfg_add_file_callback(s, ACPI_HW_ERROR_ADDR_FW_CFG_FILE, NULL, NULL,
>              NULL, &(ags->hw_error_le), sizeof(ags->hw_error_le), false);
> @@ -501,7 +519,7 @@ bool acpi_ghes_present(void)
>          return false;
>      }
>      ags = &acpi_ged_state->ghes_state;
> -    if (!ags->hw_error_le)
> +    if (!ags->hw_error_le && !ags->hest_addr_le)
>          return false;
>  
>      return true;
> diff --git a/include/hw/acpi/ghes.h b/include/hw/acpi/ghes.h
> index a3d62b96584f..454e97b5341c 100644
> --- a/include/hw/acpi/ghes.h
> +++ b/include/hw/acpi/ghes.h
> @@ -71,9 +71,14 @@ enum {
>   * meaning an offset from the etc/hardware_errors firmware address. This
>   * is the default on QEMU 9.x.
>   *
> - * An offset value equal to zero means that GHES is not present.

> + * When use_hest_addr is true, the stored offset is placed at hest_addr_le,
> + * meaning an offset from theHEST table address from etc/acpi/tables firmware.
                             ^^^^^^ missing whitespace

'offset' language is confusing here, is asks for explanation offset from what?

what is kept in hest_addr_le is GPA of HEST table, it would be better to address
wording here.
The same applies to similar comment in previous patch

> + * This is the default for QEMU 10.x and above.
> + *
> + * If both offset values are equal to zero, it means that GHES is not present
>   */
>  typedef struct AcpiGhesState {
> +    uint64_t hest_addr_le;
>      uint64_t hw_error_le;
>      bool use_hest_addr;         /* Currently, always false */
>  } AcpiGhesState;