Re: [PATCH] x86/efi: skip memattr table on kexec boot

Ard Biesheuvel
2025-01-23T09:18:04Z

On Thu, 23 Jan 2025 at 07:36, Dave Young <dyoung@redhat.com> wrote:
>
> efi_memattr_init() added a sanity check to avoid firmware caused corruption.
> The check is based on efi memmap entry numbers, but kexec only takes the
> runtime related memmap entries thus this caused many false warnings, see
> below thread for details:
>
> https://lore.kernel.org/all/20250108215957.3437660-2-usamaarif642@gmail.com/
>
> Ard suggests to skip the efi memattr table in kexec, this makes sense because
> those memattr fixups are not critical.
>
> Reported-by: Breno Leitao <leitao@debian.org>
> Reported-and-tested-by: Usama Arif <usamaarif642@gmail.com>
> Suggested-by: Ard Biesheuvel <ardb@kernel.org>
> Signed-off-by: Dave Young <dyoung@redhat.com>
>
> diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
> index 846bf49f2508..553f330198f2 100644
> --- a/arch/x86/platform/efi/quirks.c
> +++ b/arch/x86/platform/efi/quirks.c
> @@ -561,6 +561,11 @@ int __init efi_reuse_config(u64 tables, int nr_tables)
>
> if (!efi_guidcmp(guid, SMBIOS_TABLE_GUID))
> ((efi_config_table_64_t *)p)->table = data->smbios;
> +
> + /* Do not bother to play with mem attr table across kexec */
> + if (!efi_guidcmp(guid, EFI_MEMORY_ATTRIBUTES_TABLE_GUID))
> + ((efi_config_table_64_t *)p)->table = EFI_INVALID_TABLE_ADDR;
> +
> p += sz;
> }
> early_memunmap(tablep, nr_tables * sz);
>

Thanks. I've queued this up now.