Re: [PATCH 05/18] efi: split efi_enabled to efi_platform and efi_loader

[Jan Beulich]

>>> On 27.03.15 at 14:53, <address@hidden> wrote:
> On 27/03/15 13:43, Jan Beulich wrote:
>>>>> On 27.03.15 at 14:32, <address@hidden> wrote:
>>> On Fri, Feb 20, 2015 at 04:17:35PM +0000, Jan Beulich wrote:
>>>>>>> On 30.01.15 at 18:54, <address@hidden> wrote:
>>>>> We need more fine grained knowledge about EFI environment and check
>>>>> for EFI platform and EFI loader separately to properly support
>>>>> multiboot2 protocol.
>>>> ... because of ... (i.e. I can't see from the description what the
>>>> separation is good for). Looking at the comments you placed
>>>> aside the variables doesn't help me either.
>>>>
>>>>> In general Xen loaded by this protocol uses
>>>>> memory mappings and loaded modules in simliar way to Xen loaded
>>>>> by multiboot (v1) protocol. Hence, split efi_enabled to efi_platform
>>>>> and efi_loader.
>>>> And if I'm guessing things right, then introducing efi_loader but
>>>> leaving efi_enabled alone (only converting where needed) would
>>> efi_enabled is not fortunate name for new usage. Currently it means
>>> that Xen binary have or does not have EFI support build in. However,
>>> if we build in multiboot2 protocol into xen.gz then it means that
>>> it can ran on legacy BIOS or EFI platform. So, I think that we
>>> should rename efi_enabled to efi_platform because it will mean
>>> that Xen runs on EFI platform or not.
>> I disagree here.
>>
>>> efi_loader is used to differentiate between EFI native loader
>>> and multiboot2 protocol.
>> And I agree here.
> 
> I suppose "built with efi support" is known because of CONFIG_EFI or 
> not, and doesn't need a variable.
> 
> However, "booted legacy" vs "booted EFI" does need distinguishing at 
> runtime, as either is possible.

Right, but that's what efi_enabled is supposed to express after
the change; there's no need to express "built with EFI support".
It just so happens that right now, without all these changes,
built-with-EFI-support == runs-on-EFI.

Jan