Re: [PATCH v2 1/4] x86: provide an inverted Kconfig control for shim-exclusive mode

[Jan Beulich <jbeulich@xxxxxxxx>]

On 17.01.2025 13:24, Alejandro Vallejo wrote:
> On Fri Jan 17, 2025 at 10:31 AM GMT, Roger Pau Monné wrote:
>> On Thu, Jan 16, 2025 at 04:31:46PM -0800, Stefano Stabellini wrote:
>>> On Wed, 1 Mar 2023, Jan Beulich wrote:
>>>> While we want certain things turned off in shim-exclusive mode, doing
>>>> so via "depends on !PV_SHIM_EXCLUSIVE" badly affects allyesconfig: Since
>>>> that will turn on PV_SHIM_EXCLUSIVE, other options will be turned off as
>>>> a result. Yet allyesconfig wants to enable as much of the functionality
>>>> as possible.
>>>>
>>>> Retain PV_SHIM_EXCLUSIVE as a prompt-less option such that first of all
>>>> C code using it can remain as is. This isn't just for less code churn,
>>>> but also because I think that symbol is more logical to use in many
>>>> (all?) places.
>>>>
>>>> Requested-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
>>>> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
>>>>
>>>> ---
>>>> The new Kconfig control's name is up for improvement suggestions, but I
>>>> think it's already better than the originally thought of
>>>> FULL_HYPERVISOR.
>>>
>>> I think the approach in general is OK, maybe we can improve the naming
>>> further. What about one of the following?
>>>
>>> NO_PV_SHIM_EXCLUSIVE
>>> PV_SHIM_NOT_EXCLUSIVE
>>
>> IMO negated options are confusing, and if possible I think we should
>> avoid using them unless strictly necessary.
> 
> The problem is that the option is negative in nature. It's asking for
> hypervisor without _something_. I do agree with Stefano that shim would be
> better in the name. Otherwise readers are forced to play divination tricks.
> 
> How about something like:
> 
>     SHIMLESS_HYPERVISOR
> 
> That's arguably not negated, preserves "shim" in the name and has the correct
> polarity for allyesconfig to yield the right thing.

Except that a hypervisor with this option enabled isn't shim-less, but permits
working in shim as well as in non-shim mode.

Jan