Re: [PATCH v2 2/2] x86/ucode: Add Kconfig option to remove microcode loading

[Alejandro Vallejo <alejandro.garciavallejo@amd.com>]

Hi,

On Mon Jan 12, 2026 at 7:47 PM CET, Alejandro Vallejo wrote:
> On Mon Jan 12, 2026 at 6:15 PM CET, Andrew Cooper wrote:
>> On 12/01/2026 3:02 pm, Alejandro Vallejo wrote:
>>>  automation/gitlab-ci/build.yaml    |  2 +-
>>>  docs/misc/efi.pandoc               |  2 ++
>>>  docs/misc/xen-command-line.pandoc  |  4 ++--
>>>  xen/arch/x86/Kconfig               | 14 +++++++++++++-
>>>  xen/arch/x86/cpu/microcode/amd.c   | 22 +++++++++++++---------
>>>  xen/arch/x86/cpu/microcode/core.c  | 25 ++++++++++++++++++-------
>>>  xen/arch/x86/cpu/microcode/intel.c | 16 +++++++++-------
>>>  xen/arch/x86/efi/efi-boot.h        |  3 ++-
>>>  xen/arch/x86/platform_hypercall.c  |  2 ++
>>>  xen/common/Makefile                |  3 ++-
>>>  10 files changed, 64 insertions(+), 29 deletions(-)
>>
>> Much nicer in terms of (non) invasiveness.

An interesting fact came to my attention. If you set a function pointer as
IS_ENABLED(x) ? foo : NULL, rather than ifdeffing out the compiler doesn't even
need __maybe_unused to eliminate the statics.

I'm adjusting as needed and creating something so that...

  custom_param_if("ucode", parse_ucode, IS_ENABLED(CONFIG_MICROCODE_LOADING));

... does the right thing. I'm sure it'll have uses outside this (minor) patch to
remove a number of cmdline handlers when the feature they control isn't active.

Cheers,
Alejandro