Re: [PATCH v3 17/35] x86/bugs: Restructure l1tf mitigation

[Josh Poimboeuf]

On Wed, Jan 08, 2025 at 02:24:57PM -0600, David Kaplan wrote:
>  static void __init l1tf_select_mitigation(void)
> +{
> +	if (!boot_cpu_has_bug(X86_BUG_L1TF) || cpu_mitigations_off()) {
> +		l1tf_mitigation = L1TF_MITIGATION_OFF;
> +		return;
> +	}
> +
> +	if (l1tf_mitigation == L1TF_MITIGATION_AUTO) {
> +		if (cpu_mitigations_auto_nosmt())
> +			l1tf_mitigation = L1TF_MITIGATION_FLUSH_NOSMT;
> +		else
> +			l1tf_mitigation = L1TF_MITIGATION_FLUSH;
> +	}
> +
> +}

Extra whitespace.

> +
> +static void __init l1tf_apply_mitigation(void)
>  {
>  	u64 half_pa;
>  
>  	if (!boot_cpu_has_bug(X86_BUG_L1TF))
>  		return;
>  
> -	if (cpu_mitigations_off())
> -		l1tf_mitigation = L1TF_MITIGATION_OFF;
> -	else if (cpu_mitigations_auto_nosmt())
> -		l1tf_mitigation = L1TF_MITIGATION_FLUSH_NOSMT;
> -
>  	override_cache_bits(&boot_cpu_data);
>  
>  	switch (l1tf_mitigation) {
>  	case L1TF_MITIGATION_OFF:
> +		return;

Note the PTE inverstion mitigation is already done unconditionally, the
X86_FEATURE_L1TF_PTEINV bit is just for reporting that.  So this
shouldn't return.

-- 
Josh