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Date: Sat, 9 May 2020 19:05:37 +0800 From: Xiaoyao Li <xiaoyao.li@...el.com> To: Paolo Bonzini <pbonzini@...hat.com>, Thomas Gleixner <tglx@...utronix.de>, Sean Christopherson <sean.j.christopherson@...el.com>, kvm@...r.kernel.org Cc: linux-kernel@...r.kernel.org, x86@...nel.org, Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>, "H. Peter Anvin" <hpa@...or.com>, Andy Lutomirski <luto@...nel.org>, peterz@...radead.org, Arvind Sankar <nivedita@...m.mit.edu>, Tony Luck <tony.luck@...el.com>, Fenghua Yu <fenghua.yu@...el.com>, Xiaoyao Li <xiaoyao.li@...el.com> Subject: [PATCH v9 3/8] x86/split_lock: Introduce flag X86_FEATURE_SLD_FATAL and drop sld_state Introduce a synthetic feature flag X86_FEATURE_SLD_FATAL, which means kernel is in sld_fatal mode if set. Now sld_state is not needed any more that the state of SLD can be inferred from X86_FEATURE_SPLIT_LOCK_DETECT and X86_FEATURE_SLD_FATAL. Suggested-by: Sean Christopherson <sean.j.christopherson@...el.com> Signed-off-by: Xiaoyao Li <xiaoyao.li@...el.com> --- arch/x86/include/asm/cpufeatures.h | 1 + arch/x86/kernel/cpu/intel.c | 16 ++++++---------- 2 files changed, 7 insertions(+), 10 deletions(-) diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index db189945e9b0..260adfc6c61a 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -286,6 +286,7 @@ #define X86_FEATURE_FENCE_SWAPGS_USER (11*32+ 4) /* "" LFENCE in user entry SWAPGS path */ #define X86_FEATURE_FENCE_SWAPGS_KERNEL (11*32+ 5) /* "" LFENCE in kernel entry SWAPGS path */ #define X86_FEATURE_SPLIT_LOCK_DETECT (11*32+ 6) /* #AC for split lock */ +#define X86_FEATURE_SLD_FATAL (11*32+ 7) /* split lock detection in fatal mode */ /* Intel-defined CPU features, CPUID level 0x00000007:1 (EAX), word 12 */ #define X86_FEATURE_AVX512_BF16 (12*32+ 5) /* AVX512 BFLOAT16 instructions */ diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index 4602dac14dcb..93b8ccf2fa11 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -40,12 +40,6 @@ enum split_lock_detect_state { sld_fatal, }; -/* - * Default to sld_off because most systems do not support split lock detection - * split_lock_setup() will switch this to sld_warn on systems that support - * split lock detect, unless there is a command line override. - */ -static enum split_lock_detect_state sld_state __ro_after_init = sld_off; static u64 msr_test_ctrl_cache __ro_after_init; /* @@ -1043,8 +1037,9 @@ static void __init split_lock_setup(void) return; } - sld_state = state; setup_force_cpu_cap(X86_FEATURE_SPLIT_LOCK_DETECT); + if (state == sld_fatal) + setup_force_cpu_cap(X86_FEATURE_SLD_FATAL); } /* @@ -1064,7 +1059,7 @@ static void sld_update_msr(bool on) static void split_lock_init(void) { - split_lock_verify_msr(sld_state != sld_off); + split_lock_verify_msr(boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT)); } static void split_lock_warn(unsigned long ip) @@ -1083,7 +1078,7 @@ static void split_lock_warn(unsigned long ip) bool handle_guest_split_lock(unsigned long ip) { - if (sld_state == sld_warn) { + if (!boot_cpu_has(X86_FEATURE_SLD_FATAL)) { split_lock_warn(ip); return true; } @@ -1100,7 +1095,8 @@ EXPORT_SYMBOL_GPL(handle_guest_split_lock); bool handle_user_split_lock(struct pt_regs *regs, long error_code) { - if ((regs->flags & X86_EFLAGS_AC) || sld_state == sld_fatal) + if ((regs->flags & X86_EFLAGS_AC) || + boot_cpu_has(X86_FEATURE_SLD_FATAL)) return false; split_lock_warn(regs->ip); return true; -- 2.18.2
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