Re: [PATCH 1/1] x86/CPU/AMD: Avoid racy updates to MSR_K7_HWCR in set_cpuid_faulting()

[Borislav Petkov]

On Tue, Jun 09, 2026 at 02:15:47PM -0700, Jim Mattson wrote:
> +		unsigned long flags;
> +
> +		local_irq_save(flags);
>  		if (on)
>  			msr_set_bit(MSR_K7_HWCR, MSR_K7_HWCR_CPUID_USER_DIS_BIT);
>  		else
>  			msr_clear_bit(MSR_K7_HWCR, MSR_K7_HWCR_CPUID_USER_DIS_BIT);
> +		local_irq_restore(flags);
>  	}

Can we carve out this logic that modifies bits in HWCR into a separate
function and call it from everywhere it needs so that it is very obvious that
synchronization needs to happen?

Thx.

-- 
Regards/Gruss,
    Boris.

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