Re: [PATCH 1/2] efi: Disable runtime services on RT

[Thomas Gleixner <tglx@linutronix.de>]

Ard,

On Tue, Sep 28 2021 at 15:34, Ard Biesheuvel wrote:
> On Tue, 28 Sept 2021 at 15:33, Sebastian Andrzej Siewior
> <bigeasy@linutronix.de> wrote:
>>
>> On 2021-09-28 15:30:32 [+0200], Ard Biesheuvel wrote:
>> > This is generic code and the commit log only talks about arm64. How
>> > about other architectures?
>>
>> They also invoke the EFI services with disables interrupts. If they
>> provide a RTC behind spi/i2c then we end up in the same situation right?
>> Or did I misunderstand your point?
>>
> Are you sure you want to disable EFI runtime services on all x86
> systems with PREEMPT_RT as well?

I'm pretty sure because we've ran into inacceptable latencies with EFI
runtime services often enough.

Since we disabled them these complaints have gone down to 0 and nobody
so far complained about their non-availability.

We might revisit that and make them default disabled on RT and offer a
command line option to enable them for those who really want them.

Thanks,

        tglx