linux-kernel - Re: [PATCH v2 03/13] acpi/ghes: add a firmware file with HEST address

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Message-ID: <20250129162328.17680ee7@imammedo.users.ipa.redhat.com>
Date: Wed, 29 Jan 2025 16:23:28 +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 v2 03/13] acpi/ghes: add a firmware file with HEST
 address

On Wed, 29 Jan 2025 09:04:09 +0100
Mauro Carvalho Chehab <mchehab+huawei@...nel.org> wrote:

> Store HEST table address at GPA, placing its content at
> hest_addr_le variable.
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
> 
> While here, capitalize first letter on a comment about hardware_error
> address.
> 
> ---
> 
> Change from v8:
> - hest_addr_lr is now pointing to the error source size and data.
> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
> ---
>  hw/acpi/ghes.c         | 18 +++++++++++++++++-
>  include/hw/acpi/ghes.h |  1 +
>  2 files changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/hw/acpi/ghes.c b/hw/acpi/ghes.c
> index 4cabb177ad47..db6bed010eb0 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)
> @@ -261,7 +262,7 @@ static void build_ghes_error_table(GArray *hardware_errors, BIOSLinker *linker,
>      }
>  
>      /*
> -     * tell firmware to write hardware_errors GPA into
> +     * Tell firmware to write hardware_errors GPA into
>       * hardware_errors_addr fw_cfg, once the former has been initialized.
>       */

please, drop non relevant hunk, or move it out into a separate path

>      bios_linker_loader_write_pointer(linker, ACPI_HW_ERROR_ADDR_FW_CFG_FILE, 0,
> @@ -349,12 +350,15 @@ void acpi_build_hest(GArray *table_data, GArray *hardware_errors,
>  {
>      AcpiTable table = { .sig = "HEST", .rev = 1,
>                          .oem_id = oem_id, .oem_table_id = oem_table_id };
> +    uint32_t hest_offset;
>      int i;
>  
>      build_ghes_error_table(hardware_errors, linker, num_sources);
>  
>      acpi_table_begin(&table, table_data);
>  
> +    hest_offset = table_data->len;
move it before acpi_table_begin() so that name would match with what actually happens
and adjust 4/13 to account for that

> +
>      /* Error Source Count */
>      build_append_int_noprefix(table_data, num_sources, 4);
>      for (i = 0; i < num_sources; i++) {
> @@ -362,6 +366,15 @@ void acpi_build_hest(GArray *table_data, GArray *hardware_errors,
>      }
>  
>      acpi_table_end(linker, &table);
> +
> +    /*
> +     * 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);

it's not safe to add this without compat logic, as it changes size of linker
table and possibly layout.

I'd suggest to  partially combine this with use_hest_addr patch.
One way to do it cleanly would be to move part introducing
use_hest_addr here and set it to false to start with,
and flip default to true one all hest_addr_le code in place.
see related comment 6/13 

>  }
>  
>  void acpi_ghes_add_fw_cfg(AcpiGhesState *ags, FWCfgState *s,
> @@ -375,6 +388,9 @@ void acpi_ghes_add_fw_cfg(AcpiGhesState *ags, FWCfgState *s,
>      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);
>  
> +    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);
see 6/13 comments

> +
>      ags->present = true;
>  }
>  
> diff --git a/include/hw/acpi/ghes.h b/include/hw/acpi/ghes.h
> index 9f0120d0d596..237721fec0a2 100644
> --- a/include/hw/acpi/ghes.h
> +++ b/include/hw/acpi/ghes.h
> @@ -58,6 +58,7 @@ enum AcpiGhesNotifyType {
>  };
>  
>  typedef struct AcpiGhesState {
> +    uint64_t hest_addr_le;
>      uint64_t hw_error_le;
>      bool present; /* True if GHES is present at all on this board */
>  } AcpiGhesState;