Re: [PATCH] xen/arm: Move TEE mediators in a kconfig submenu

[Bertrand Marquis <Bertrand.Marquis@xxxxxxx>]

Hi Jan,

> On 21 Jul 2023, at 12:45, Jan Beulich <jbeulich@xxxxxxxx> wrote:
> 
> On 21.07.2023 11:02, Bertrand Marquis wrote:
>>> On 21 Jul 2023, at 10:52, Jan Beulich <jbeulich@xxxxxxxx> wrote:
>>> On 21.07.2023 10:02, Bertrand Marquis wrote:
>>>> --- a/xen/arch/arm/tee/Kconfig
>>>> +++ b/xen/arch/arm/tee/Kconfig
>>>> @@ -1,7 +1,17 @@
>>>> +menu "TEE mediators"
>>>> + visible if UNSUPPORTED
>>> 
>>> With this ...
>>> 
>>>> +config TEE
>>>> + bool
>>>> + default n
>>>> + help
>>>> +  This option enables generic TEE mediators support. It allows guests
>>>> +  to access real TEE via one of TEE mediators implemented in XEN.
>>>> +
>>>> config OPTEE
>>>> - bool "Enable OP-TEE mediator"
>>>> + bool "Enable OP-TEE mediator (UNSUPPORTED)" if UNSUPPORTED
>>> 
>>> ... you shouldn't need the "if" here, and ...
>>> 
>>>> default n
>>>> - depends on TEE
>>>> + select TEE
>>>> help
>>>> Enable the OP-TEE mediator. It allows guests to access
>>>> OP-TEE running on your platform. This requires
>>>> @@ -13,9 +23,13 @@ config FFA
>>>> bool "Enable FF-A mediator support (UNSUPPORTED)" if UNSUPPORTED
>>> 
>>> ... you could drop the one here. I think.
>> 
>> visible if is only for the GUI/ncurse display but the if is required
>> to make sure that a .config file cannot set CONFIG_TEE or
>> CONFIG_FFA if. UNSUPPORTED is not selected.
> 
> Is what you describe "depends on"? "if" controls merely prompt
> visibility aiui.

So you think that having  CONFIG_FFA without CONFIG_UNSUPPORTED
would be a valid configuration and the if is only here for the gui ?

I tested that with the following procedure:
- use menuconfig, select UNSUPPORTED and FFA
- edit .config and disable UNSUPPORTED but keep FFA
- build
- CONFIG_FFA is removed from .config

Now what puzzles me is that i did the same but removing the if UNSUPPORTED
for TEE and FFA and i have exactly the same behaviour.

So it seems that "if UNSUPPORTED" and visibility all behave in the same way
as depends on which i was not expecting.

So what should i keep or remove here ?

Cheers
Bertrand

> 
> Jan