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SubjectRe: [PATCH] x86/cpuinfo: Clear X86_FEATURE_TME if TME/MKTME is disabled by BIOS
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On Tue, 2022-06-14 at 18:02 -0300, Martin Fernandez 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);

The above code seems only clear TME on BSP, if I read correctly. Why not
unconditionally clear this flag? If TME is detected as not enabled by BIOS on
*this* cpu, then the flag for *this* cpu should be cleared.

Also could you CC Kirill A. Shutemov <kirill.shutemov@linux.intel.com>, who is
the original author of this code?


> mktme_status = MKTME_DISABLED;
> return;
> }
> --
> 2.30.2
>

--
Thanks,
-Kai


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