linux-kernel - [tip: x86/cpu] x86/cpu: Clear TME feature flag if TME is not enabled by BIOS

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Date: Tue, 26 Mar 2024 08:56:04 -0000
From: "tip-bot2 for Bingsong Si" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Bingsong Si <sibs@...natelecom.cn>, Ingo Molnar <mingo@...nel.org>,
 "Huang, Kai" <kai.huang@...el.com>, x86@...nel.org,
 linux-kernel@...r.kernel.org
Subject:
 [tip: x86/cpu] x86/cpu: Clear TME feature flag if TME is not enabled by BIOS

The following commit has been merged into the x86/cpu branch of tip:

Commit-ID:     cd2236c2f49eb46443fd7573d0ddad5373577b11
Gitweb:        https://git.kernel.org/tip/cd2236c2f49eb46443fd7573d0ddad5373577b11
Author:        Bingsong Si <sibs@...natelecom.cn>
AuthorDate:    Mon, 11 Mar 2024 15:19:37 +08:00
Committer:     Ingo Molnar <mingo@...nel.org>
CommitterDate: Tue, 26 Mar 2024 09:49:32 +01:00

x86/cpu: Clear TME feature flag if TME is not enabled by BIOS

When TME is disabled by BIOS, the dmesg output is:

  x86/tme: not enabled by BIOS

.. and TME functionality is not enabled by the kernel, but the TME feature
is still shown in /proc/cpuinfo.

Clear it.

[ mingo: Clarified changelog ]

Signed-off-by: Bingsong Si <sibs@...natelecom.cn>
Signed-off-by: Ingo Molnar <mingo@...nel.org>
Cc: "Huang, Kai" <kai.huang@...el.com>
Link: https://lore.kernel.org/r/20240311071938.13247-1-sibs@chinatelecom.cn
---
 arch/x86/kernel/cpu/intel.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index be30d7f..3c3e7e5 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -228,6 +228,7 @@ static void detect_tme_early(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");
 		mktme_status = MKTME_DISABLED;
+		clear_cpu_cap(c, X86_FEATURE_TME);
 		return;
 	}