Re: [PATCH v5 2/3] x86/acpi: Integrate BGRT preservation with status reporting

[Jan Beulich <jbeulich@xxxxxxxx>]

On 24.03.2026 13:33, Soumyajyotii Ssarkar wrote:
> @@ -327,6 +328,11 @@ static int __init cf_check acpi_parse_hpet(struct 
> acpi_table_header *table)
>       return 0;
>  }
> 
> +/*
> + * Invalidate BGRT if image is in conventional RAM (preservation failed).
> + * If preservation succeeded, image is in EfiACPIReclaimMemory, which
> + * won't match RAM_TYPE_CONVENTIONAL check, so table remains valid.
> + */
>  static int __init cf_check acpi_invalidate_bgrt(struct acpi_table_header 
> *table)
>  {
>       struct acpi_table_bgrt *bgrt_tbl =
> @@ -754,5 +760,7 @@ int __init acpi_boot_init(void)
> 
>       acpi_table_parse(ACPI_SIG_BGRT, acpi_invalidate_bgrt);
> 
> +     efi_bgrt_status_info();
> +
>       return 0;
>  }

Does this really need doing from here? If you called it ...

> --- a/xen/common/efi/boot.c
> +++ b/xen/common/efi/boot.c
> @@ -1911,6 +1911,22 @@ static bool __init cf_check rt_range_valid(unsigned 
> long smfn, unsigned long emf
>      return true;
>  }
> 
> +void __init efi_bgrt_status_info(void)
> +{
> +    if ( !efi_enabled(EFI_BOOT) )
> +        return;
> +
> +    if ( bgrt_info.preserved )
> +    {
> +        printk(XENLOG_INFO "EFI: BGRT image preserved: %lu KB\n",
> +               bgrt_info.size / 1024);
> +        printk(XENLOG_INFO "EFI: BGRT relocated from %p to %p\n",
> +               bgrt_info.old_addr, bgrt_info.new_addr);
> +    }
> +    else if ( bgrt_info.failure_reason[0] )
> +        printk(XENLOG_WARNING "EFI: BGRT preservation failed: %s\n",
> +               bgrt_info.failure_reason);
> +}
> 
>  void __init efi_init_memory(void)
>  {

... out of this function, it could be static and no stub (misplaced in
the earlier patch) would be needed either.

Furthermore, is the EFI_BOOT check really needed? Without taking either
of the EFI boot paths, neither bgrt_info.preserved nor
bgrt_info.failure_reason[0] would have been altered from their initial
values.

Jan