linux-kernel - Re: [PATCH] kernel/cpu/bugs: log ltf1 mitigation status

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Message-ID: <20250602090942.GAaD1qVv5182lZSPtK@fat_crate.local>
Date: Mon, 2 Jun 2025 11:09:42 +0200
From: Borislav Petkov <bp@...en8.de>
To: pawan.kumar.gupta@...ux.intel.com
Cc: Khalid Ali <khaliidcaliy@...il.com>, tglx@...utronix.de,
	peterz@...radead.org, jpoimboe@...nel.org, mingo@...hat.com,
	dave.hansen@...ux.intel.com, linux-kernel@...r.kernel.org,
	x86@...nel.org, hpa@...or.com
Subject: Re: [PATCH] kernel/cpu/bugs: log ltf1 mitigation status

On Mon, Jun 02, 2025 at 07:37:06AM +0000, Khalid Ali wrote:
> Log the L1TF mitigation like other mitigatioons. This one is is the
> only one that doesn't get logged.
> 
> Signed-off-by: Khalid Ali <khaliidcaliy@...il.com>
> ---
>  arch/x86/kernel/cpu/bugs.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
> index 7f94e6a5497d..38cb2a1b2849 100644
> --- a/arch/x86/kernel/cpu/bugs.c
> +++ b/arch/x86/kernel/cpu/bugs.c
> @@ -2803,6 +2803,7 @@ static void __init l1tf_apply_mitigation(void)
>  		return;
>  	}
>  
> +	pr_info("Mitigation: PTE inversion\n");
>  	setup_force_cpu_cap(X86_FEATURE_L1TF_PTEINV);
>  }

Pawan, what's the story here?

There's this stuff further down in that file:

| #define L1TF_DEFAULT_MSG "Mitigation: PTE Inversion"
|         
| #if IS_ENABLED(CONFIG_KVM_INTEL)
| static const char * const l1tf_vmx_states[] = {

which comes from 2018:

72c6d2db64fa ("x86/litf: Introduce vmx status variable")

I guess it is about time we made this mitigation also follow the common
pattern with the mitigation strings and issuing them at the right time?

:-)

Thx.

-- 
Regards/Gruss,
    Boris.

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