[PATCH] efi_loader: optional persistence of variables

[Heinrich Schuchardt]

On 3/22/22 23:16, Tom Saeger wrote:
> On Tue, Mar 22, 2022 at 10:41:40PM +0100, Heinrich Schuchardt wrote:
>> On 3/22/22 22:21, Tom Saeger wrote:
>>> Since be66b89da306 ("efi_loader: configuration of variables store")
>>> the choice of EFI_VARIABLE_FILE_STORE or EFI_MM_COMM_TEE
>>> is mutually-exclusive, however efi_var_to_file also allows
>>> for "neither".  Set Kconfig choice optional.
>>>
>>> Signed-off-by: Tom Saeger <tom.saeger at oracle.com>
>>> ---
>>>    lib/efi_loader/Kconfig | 1 +
>>>    1 file changed, 1 insertion(+)
>>>
>>> diff --git a/lib/efi_loader/Kconfig b/lib/efi_loader/Kconfig
>>> index e5e35fe51f65..9add2a286ff4 100644
>>> --- a/lib/efi_loader/Kconfig
>>> +++ b/lib/efi_loader/Kconfig
>>> @@ -44,6 +44,7 @@ config EFI_SETUP_EARLY
>>>
>>>    choice
>>>    	prompt "Store for non-volatile UEFI variables"
>>> +	optional
>>
>> Storing non-volatile variables is required by the UEFI specification.
>>
>> How should a user understand that a boot option he just created vanishes
>> upon reboot?
>>
>> Please, explain your use case.
>
> bootefi ${kernel_addr}
>
> in this case linux kernel for an Armv8 platform.
> This platform does not want or need any variables to persist.
>
> bootefi eventually calls efi_var_from_file(), where *NOT* defining
> CONFIG_EFI_VARIABLE_FILE_STORE would allow this use case to work,
> otherwise it fails.  This was possible before
> be66b89da306 ("efi_loader: configuration of variables store").

Please, describe exactly what does not work. Is it building or is it
running the bootefi command?

Does your system have an ESP?

Where does bootefi fail?

Best regards

Heinrich

>
> Thoughts?
>
> --Tom
>
>>
>> Best regards
>>
>> Heinrich
>>
>>>    	default EFI_VARIABLE_FILE_STORE
>>>    	help
>>>    	  Select where non-volatile UEFI variables shall be stored.
>>>
>>> base-commit: 5f68470d69f853b1652ebe93525b60064717fe2e
>>