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References: <20220614210217.1940563-1-martin.fernandez@eclypsium.com>
In-Reply-To: <20220614210217.1940563-1-martin.fernandez@eclypsium.com>
From:   Richard Hughes <hughsient@gmail.com>
Date:   Tue, 14 Jun 2022 22:05:49 +0100
Message-ID: <CAD2FfiHpe0Dp+_t1D1giktX7R5ZDagoUf34yUGTkQAJBhwtxMA@mail.gmail.com>
Subject: Re: [PATCH] x86/cpuinfo: Clear X86_FEATURE_TME if TME/MKTME is
 disabled by BIOS
To:     Martin Fernandez <martin.fernandez@eclypsium.com>
Cc:     linux-kernel@vger.kernel.org, bp@alien8.de,
        dave.hansen@linux.intel.com, x86@kernel.org, mingo@redhat.com,
        tglx@linutronix.de, daniel.gutson@eclypsium.com,
        alex.bazhaniuk@eclypsium.com
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Tested-by: Richard Hughes <richard@hughsie.com>

On Tue, 14 Jun 2022 at 22:02, Martin Fernandez
<martin.fernandez@eclypsium.com> wrote:
>
> Right now the only way to check this is by greping the kernel logs,
> which is inconvinient. This is currently checked for fwupd for
> example.
>
> I understand that cpuinfo is supposed to report every feature in the
> cpu but since AMD is doing the same for sme/sev I think is good to
> have this for Intel too.
>
> Signed-off-by: Martin Fernandez <martin.fernandez@eclypsium.com>
> ---
>  arch/x86/kernel/cpu/intel.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
> index fd5dead8371c..7311172aceaf 100644
> --- a/arch/x86/kernel/cpu/intel.c
> +++ b/arch/x86/kernel/cpu/intel.c
> @@ -570,6 +570,8 @@ static void detect_tme(struct cpuinfo_x86 *c)
>
>         if (!TME_ACTIVATE_LOCKED(tme_activate) || !TME_ACTIVATE_ENABLED(tme_activate)) {
>                 pr_info_once("x86/tme: not enabled by BIOS\n");
> +               if (mktme_status == MKTME_UNINITIALIZED)
> +                       clear_cpu_cap(c, X86_FEATURE_TME);
>                 mktme_status = MKTME_DISABLED;
>                 return;
>         }
> --
> 2.30.2
>