Re: [PATCH v2 1/3] x86/mce/inject: Remove call to mce_notify_irq()

[Borislav Petkov]

On Mon, Feb 10, 2025 at 05:47:04PM +0200, Nikolay Borisov wrote:
> The call is actually a noop because when the MCE is raised the early
> notifier is the only call site that correctly calls mce_notify_irq()
> because it also sets mce_need_notify. Remove this call and as a result
> make mce_notify_irq() static
> 
> Signed-off-by: Nikolay Borisov <nik.borisov@xxxxxxxx>
> ---
>  arch/x86/include/asm/mce.h       |  2 --
>  arch/x86/kernel/cpu/mce/core.c   | 44 ++++++++++++++++----------------
>  arch/x86/kernel/cpu/mce/inject.c |  1 -
>  3 files changed, 22 insertions(+), 25 deletions(-)

So what you're looking at are the remnants of the old soft-inject of MCE
errors. And it seems that we lost some of that functionality along the way and
no one has noticed because, well, it seems no one uses it anymore.

In order to understand how this thing was supposed to work, checkout

ea149b36c7f5 ("x86, mce: add basic error injection infrastructure")

and follow what raise_mce() does and pay attention to notify_user which is
what mce_need_notify was called back then.

Remember to have fun :-P

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette