linux-kernel - Re: [PATCH v2 10/15] acpi/ghes: move offset calculus to a separate function

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Message-ID: <20241002152027.6b90e8cd@imammedo.users.ipa.redhat.com>
Date: Wed, 2 Oct 2024 15:20:27 +0200
From: Igor Mammedov <imammedo@...hat.com>
To: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
Cc: "Michael S. Tsirkin" <mst@...hat.com>, Ani Sinha <anisinha@...hat.com>,
 Dongjiu Geng <gengdongjiu1@...il.com>, linux-kernel@...r.kernel.org,
 qemu-arm@...gnu.org, qemu-devel@...gnu.org, Jonathan Cameron
 <Jonathan.Cameron@...wei.com>
Subject: Re: [PATCH v2 10/15] acpi/ghes: move offset calculus to a separate
 function

On Tue,  1 Oct 2024 09:03:47 +0200
Mauro Carvalho Chehab <mchehab+huawei@...nel.org> wrote:

> Currently, CPER address location is calculated as an offset of
> the hardware_errors table. It is also badly named, as the
> offset actually used is the address where the CPER data starts,
> and not the beginning of the error source.
> 
> Move the logic which calculates such offset to a separate
> function, in preparation for a patch that will be changing the
> logic to calculate it from the HEST table.
> 
> While here, properly name the variable which stores the cper
> address.

I'd move 14/15 into the beginning of the series,
so this patch would look a bit more sensible.

> 
> Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@...wei.com>
> ---
>  hw/acpi/ghes.c | 50 +++++++++++++++++++++++++++++++-------------------
>  1 file changed, 31 insertions(+), 19 deletions(-)
> 
> diff --git a/hw/acpi/ghes.c b/hw/acpi/ghes.c
> index 628fa9b22f4b..900f1571bc97 100644
> --- a/hw/acpi/ghes.c
> +++ b/hw/acpi/ghes.c
> @@ -378,11 +378,36 @@ void acpi_ghes_add_fw_cfg(AcpiGhesState *ags, FWCfgState *s,
>      ags->present = true;
>  }
>  
> +static void get_ghes_offsets(uint64_t ghes_addr,
> +                             uint64_t *cper_addr,
> +                             uint64_t *read_ack_register_addr)
> +{
> +    if (!ghes_addr) {
> +        return;
> +    }
> +
> +    /*
> +     * non-HEST version supports only one source, so no need to change
> +     * the start offset based on the source ID. Also, we can't validate
> +     * the source ID, as it is stored inside the HEST table.
> +     */
> +
> +    cpu_physical_memory_read(ghes_addr, cper_addr,
> +                             sizeof(*cper_addr));
> +
> +    *cper_addr = le64_to_cpu(*cper_addr);
> +
> +    /*
> +     * As the current version supports only one source, the ack offset is
> +     * just sizeof(uint64_t).
> +     */
> +    *read_ack_register_addr = ghes_addr + sizeof(uint64_t);
> +}
> +
>  void ghes_record_cper_errors(const void *cper, size_t len,
>                               uint16_t source_id, Error **errp)
>  {
> -    uint64_t error_block_addr, read_ack_register_addr, read_ack_register = 0;
> -    uint64_t start_addr;
> +    uint64_t cper_addr = 0, read_ack_register_addr = 0, read_ack_register;
>      AcpiGedState *acpi_ged_state;
>      AcpiGhesState *ags;
>  
> @@ -396,27 +421,14 @@ void ghes_record_cper_errors(const void *cper, size_t len,
>      g_assert(acpi_ged_state);
>      ags = &acpi_ged_state->ghes_state;
>  
> -    /*
> -     * Current version supports only one source, as assured during table build,
> -     * so no need to change the start offset based on the source ID.
> -     */
> -    start_addr = le64_to_cpu(ags->ghes_addr_le);
> +    get_ghes_offsets(le64_to_cpu(ags->ghes_addr_le),
> +                     &cper_addr, &read_ack_register_addr);
>  
> -    cpu_physical_memory_read(start_addr, &error_block_addr,
> -                             sizeof(error_block_addr));
> -
> -    error_block_addr = le64_to_cpu(error_block_addr);
> -    if (!error_block_addr) {
> +    if (!cper_addr) {
>          error_setg(errp, "can not find Generic Error Status Block");
>          return;
>      }
>  
> -    /*
> -     * As the current version supports only one source, the ack offset is
> -     * just sizeof(uint64_t).
> -     */
> -    read_ack_register_addr = start_addr + sizeof(uint64_t);
> -
>      cpu_physical_memory_read(read_ack_register_addr,
>                               &read_ack_register, sizeof(read_ack_register));
>  
> @@ -437,7 +449,7 @@ void ghes_record_cper_errors(const void *cper, size_t len,
>          &read_ack_register, sizeof(uint64_t));
>  
>      /* Write the generic error data entry into guest memory */
> -    cpu_physical_memory_write(error_block_addr, cper, len);
> +    cpu_physical_memory_write(cper_addr, cper, len);
>  
>      return;
>  }