[PATCH v6 08/20] x86/split_lock: Enumerate split lock detection on Icelake mobile processor

From: Fenghua Yu <fenghua.yu@intel.com>
To: "Thomas Gleixner" <tglx@linutronix.de>,
	"Ingo Molnar" <mingo@redhat.com>,
	"Borislav Petkov" <bp@alien8.de>, "H Peter Anvin" <hpa@zytor.com>,
	"Dave Hansen" <dave.hansen@intel.com>,
	"Paolo Bonzini" <pbonzini@redhat.com>,
	"Ashok Raj" <ashok.raj@intel.com>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Kalle Valo" <kvalo@codeaurora.org>,
	"Xiaoyao Li " <xiaoyao.li@intel.com>,
	"Michael Chan" <michael.chan@broadcom.com>,
	"Ravi V Shankar" <ravi.v.shankar@intel.com>
Cc: "linux-kernel" <linux-kernel@vger.kernel.org>,
	"x86" <x86@kernel.org>,
	linux-wireless@vger.kernel.org, netdev@vger.kernel.org,
	kvm@vger.kernel.org, Fenghua Yu <fenghua.yu@intel.com>
Subject: [PATCH v6 08/20] x86/split_lock: Enumerate split lock detection on Icelake mobile processor
Date: Wed,  3 Apr 2019 14:21:54 -0700	[thread overview]
Message-ID: <1554326526-172295-9-git-send-email-fenghua.yu@intel.com> (raw)
In-Reply-To: <1554326526-172295-1-git-send-email-fenghua.yu@intel.com>

Icelake mobile processor can detect split lock operations although
the processor doesn't have MSR_IA32_CORE_CAPABILITY and split lock
detection bit in the MSR. Set split lock detection feature bit
X86_FEATURE_SPLIT_LOCK_DETECT on the processor based on its
family/model/stepping.

A few other processors may also have the feature but don't have
MSR_IA32_CORE_CAPABILITY. The feature will be enumerated on those
processors once their family/model/stepping information is released.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
---
 arch/x86/kernel/cpu/intel.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
index ad3f72d106fc..7f6943af35dc 100644
--- a/arch/x86/kernel/cpu/intel.c
+++ b/arch/x86/kernel/cpu/intel.c
@@ -1038,8 +1038,18 @@ void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c)
 {
 	u64 ia32_core_cap = 0;
 
-	if (!cpu_has(c, X86_FEATURE_CORE_CAPABILITY))
+	if (!cpu_has(c, X86_FEATURE_CORE_CAPABILITY)) {
+		/*
+		 * The following processors have split lock detection feature.
+		 * But since they don't have MSR_IA32_CORE_CAPABILITY, the
+		 * feature cannot be enumerated by the MSR. So enumerate the
+		 * feature by family/model/stepping.
+		 */
+		if (c->x86 == 6 && c->x86_model == INTEL_FAM6_ICELAKE_MOBILE)
+			set_split_lock_detect();
+
 		return;
+	}
 
 	/*
 	 * If MSR_IA32_CORE_CAPABILITY exists, enumerate features that are
-- 
2.19.1

