From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Campbell <ian.campbell@citrix.com>
Subject: Re: Usage of efi_enabled - Was: Re: [PATCH RFC 33/35]
 arm : acpi enable efi for acpi
Date: Wed, 11 Feb 2015 10:49:26 +0000
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To: Jan Beulich <JBeulich@suse.com>
Cc: Julien Grall <julien.grall@linaro.org>, tim@xen.org, "xen-devel@lists.xen.org" <xen-devel@lists.xen.org>, Roy Franz <roy.franz@linaro.org>, stefano.stabellini@citrix.com, Parth Dixit <parth.dixit@linaro.org>, christoffer.dall@linaro.org
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On Wed, 2015-02-11 at 10:28 +0000, Jan Beulich wrote:
> >>> On 11.02.15 at 10:51, <julien.grall@linaro.org> wrote:
> >> --- a/xen/common/efi/runtime.c
> >> +++ b/xen/common/efi/runtime.c
> >> @@ -11,7 +11,13 @@ DEFINE_XEN_GUEST_HANDLE(CHAR16);
> >>   #ifndef COMPAT
> >>
> >>   #ifdef CONFIG_ARM  /* Disabled until runtime services implemented */
> >> +
> >> +#if defined(CONFIG_ARM_64) && defined(CONFIG_ACPI)
> >> +const bool_t efi_enabled = 1;
> >> +#else
> >>   const bool_t efi_enabled = 0;
> >> +#endif
> >> +
> > 
> > Thinking a bit more about this variable. The usage of the variable is 
> > unclear. Does it mean that Xen is supporting EFI runtime or Xen has been 
> > boot with EFI?
> 
> The latter (it just so happens that it also means the former on x86
> for the time being).
> 
> > The binary produced on ARM64 always is able to boot with and without 
> > EFI. So it would seems logical to me that the value of this variable may 
> > change at runtime.
> 
> Correct - other than (currently) on x86.

IOW it should become non-const on !x86? 

Does that also imply that some code which is using it to signal
availability of Runtime Services should be switch to some other (new?)
variable?

Ian