Re: [PATCH v8 8/9] x86/mtrr: Avoid repeated save of MTRRs on boot-time CPU bringup

From: Thomas Gleixner
Date: Thu Feb 09 2023 - 13:31:22 EST


On Thu, Feb 09 2023 at 15:41, Usama Arif wrote:
> void mtrr_save_state(void)
> {
> + static bool mtrr_saved;
> int first_cpu;
>
> if (!mtrr_enabled())
> return;
>
> + if (system_state < SYSTEM_RUNNING) {
> + if (!mtrr_saved) {
> + mtrr_save_fixed_ranges(NULL);
> + mtrr_saved = true;
> + }
> + return;
> + }
> +
> first_cpu = cpumask_first(cpu_online_mask);
> smp_call_function_single(first_cpu, mtrr_save_fixed_ranges, NULL, 1);

So why is this relevant after the initial bringup? The BP MTRRs have
been saved already above, no?

Thanks,

tglx