[PATCH] x86/tsx: Use MSR_TSX_CTRL to clear CPUID bits

From: Pawan Gupta
Date: Wed Feb 09 2022 - 16:04:43 EST


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@xxxxxxxxx>
Tested-by: Neelima Krishnan <neelima.krishnan@xxxxxxxxx>
Signed-off-by: Pawan Gupta <pawan.kumar.gupta@xxxxxxxxxxxxxxx>
---
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