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Message-Id: <1556134382-58814-14-git-send-email-fenghua.yu@intel.com> Date: Wed, 24 Apr 2019 12:33:00 -0700 From: Fenghua Yu <fenghua.yu@...el.com> To: "Thomas Gleixner" <tglx@...utronix.de>, "Ingo Molnar" <mingo@...hat.com>, "Borislav Petkov" <bp@...en8.de>, "H Peter Anvin" <hpa@...or.com>, "Paolo Bonzini" <pbonzini@...hat.com>, "Dave Hansen" <dave.hansen@...el.com>, "Ashok Raj" <ashok.raj@...el.com>, "Peter Zijlstra" <peterz@...radead.org>, "Ravi V Shankar" <ravi.v.shankar@...el.com>, "Xiaoyao Li " <xiaoyao.li@...el.com>, "Christopherson Sean J" <sean.j.christopherson@...el.com>, "Kalle Valo" <kvalo@...eaurora.org>, "Michael Chan" <michael.chan@...adcom.com> Cc: "linux-kernel" <linux-kernel@...r.kernel.org>, "x86" <x86@...nel.org>, kvm@...r.kernel.org, netdev@...r.kernel.org, linux-wireless@...r.kernel.org, Fenghua Yu <fenghua.yu@...el.com> Subject: [PATCH v8 13/15] x86/split_lock: Enable split lock detection by default A split locked access locks bus and degrades overall memory access performance. When split lock detection feature is enumerated, enable the feature by default by writing 1 to bit 29 in MSR TEST_CTL to find any split lock issue. Signed-off-by: Fenghua Yu <fenghua.yu@...el.com> --- arch/x86/kernel/cpu/intel.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index 2cc69217ca7c..28cc6891ba48 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -657,6 +657,13 @@ static void init_intel_misc_features(struct cpuinfo_x86 *c) wrmsrl(MSR_MISC_FEATURES_ENABLES, msr); } +static void split_lock_update_msr(void) +{ + /* Enable split lock detection */ + msr_set_bit(MSR_TEST_CTL, TEST_CTL_SPLIT_LOCK_DETECT_SHIFT); + this_cpu_or(msr_test_ctl_cache, TEST_CTL_SPLIT_LOCK_DETECT); +} + static void init_split_lock_detect(struct cpuinfo_x86 *c) { if (cpu_has(c, X86_FEATURE_SPLIT_LOCK_DETECT)) { @@ -665,6 +672,8 @@ static void init_split_lock_detect(struct cpuinfo_x86 *c) /* Cache MSR TEST_CTL */ rdmsrl(MSR_TEST_CTL, test_ctl_val); this_cpu_write(msr_test_ctl_cache, test_ctl_val); + + split_lock_update_msr(); } } @@ -1045,9 +1054,13 @@ static const struct cpu_dev intel_cpu_dev = { cpu_dev_register(intel_cpu_dev); +#undef pr_fmt +#define pr_fmt(fmt) "x86/split lock detection: " fmt + static void __init set_split_lock_detect(void) { setup_force_cpu_cap(X86_FEATURE_SPLIT_LOCK_DETECT); + pr_info("enabled\n"); } void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c) -- 2.19.1
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