linux-kernel - [PATCH] x86/tsx: Use MSR_TSX

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Message-ID: <5bd785a1d6ea0b572250add0c6617b4504bc24d1.1644440311.git.pawan.kumar.gupta@linux.intel.com>
Date:   Wed, 9 Feb 2022 13:04:36 -0800
From:   Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>
To:     Thomas Gleixner <tglx@...utronix.de>,
        Borislav Petkov <bp@...en8.de>
Cc:     Ingo Molnar <mingo@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
        "H. Peter Anvin" <hpa@...or.com>, Andi Kleen <ak@...ux.intel.com>,
        Tony Luck <tony.luck@...el.com>, linux-kernel@...r.kernel.org,
        antonio.gomez.iglesias@...ux.intel.com, neelima.krishnan@...el.com
Subject: [PATCH] x86/tsx: Use MSR_TSX_CTRL to clear CPUID bits

tsx_clear_cpuid() uses MSR_TSX_FORCE_ABORT to clear CPUID.RTM and
CPUID.HLE. Not all CPUs support MSR_TSX_FORCE_ABORT, alternatively use
MSR_IA32_TSX_CTRL when supported.

Fixes: 293649307ef9 ("x86/tsx: Clear CPUID bits when TSX always force aborts")
Reported-by: kernel test robot <lkp@...el.com>
Tested-by: Neelima Krishnan <neelima.krishnan@...el.com>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@...ux.intel.com>
---
 arch/x86/kernel/cpu/tsx.c | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kernel/cpu/tsx.c b/arch/x86/kernel/cpu/tsx.c
index 9c7a5f049292..c2343ea911e8 100644
--- a/arch/x86/kernel/cpu/tsx.c
+++ b/arch/x86/kernel/cpu/tsx.c
@@ -58,7 +58,7 @@ void tsx_enable(void)
 	wrmsrl(MSR_IA32_TSX_CTRL, tsx);
 }
 
-static bool __init tsx_ctrl_is_supported(void)
+static bool tsx_ctrl_is_supported(void)
 {
 	u64 ia32_cap = x86_read_arch_cap_msr();
 
@@ -97,6 +97,10 @@ void tsx_clear_cpuid(void)
 		rdmsrl(MSR_TSX_FORCE_ABORT, msr);
 		msr |= MSR_TFA_TSX_CPUID_CLEAR;
 		wrmsrl(MSR_TSX_FORCE_ABORT, msr);
+	} else if (tsx_ctrl_is_supported()) {
+		rdmsrl(MSR_IA32_TSX_CTRL, msr);
+		msr |= TSX_CTRL_CPUID_CLEAR;
+		wrmsrl(MSR_IA32_TSX_CTRL, msr);
 	}
 }
 
@@ -106,13 +110,11 @@ void __init tsx_init(void)
 	int ret;
 
 	/*
-	 * Hardware will always abort a TSX transaction if both CPUID bits
-	 * RTM_ALWAYS_ABORT and TSX_FORCE_ABORT are set. In this case, it is
-	 * better not to enumerate CPUID.RTM and CPUID.HLE bits. Clear them
-	 * here.
+	 * Hardware will always abort a TSX transaction when CPUID
+	 * RTM_ALWAYS_ABORT is set. In this case, it is better not to enumerate
+	 * CPUID.RTM and CPUID.HLE bits. Clear them here.
 	 */
-	if (boot_cpu_has(X86_FEATURE_RTM_ALWAYS_ABORT) &&
-	    boot_cpu_has(X86_FEATURE_TSX_FORCE_ABORT)) {
+	if (boot_cpu_has(X86_FEATURE_RTM_ALWAYS_ABORT)) {
 		tsx_ctrl_state = TSX_CTRL_RTM_ALWAYS_ABORT;
 		tsx_clear_cpuid();
 		setup_clear_cpu_cap(X86_FEATURE_RTM);
-- 
2.31.1