| Message ID | 20200315050517.127446-5-xiaoyao.li@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | x86/split_lock: Add feature split lock detection | expand |
On Sun, Mar 15, 2020 at 01:05:12PM +0800, Xiaoyao Li wrote: > In the future, KVM will use handle_user_split_lock() to handle #AC > caused by split lock in guest. Due to the fact that KVM doesn't have > a @regs context and will pre-check EFLASG.AC, move the EFLAGS.AC check > to do_alignment_check(). > > Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com> > Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> > --- > arch/x86/include/asm/cpu.h | 4 ++-- > arch/x86/kernel/cpu/intel.c | 7 ++++--- > arch/x86/kernel/traps.c | 2 +- > 3 files changed, 7 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h > index ff6f3ca649b3..ff567afa6ee1 100644 > --- a/arch/x86/include/asm/cpu.h > +++ b/arch/x86/include/asm/cpu.h > @@ -43,11 +43,11 @@ unsigned int x86_stepping(unsigned int sig); > #ifdef CONFIG_CPU_SUP_INTEL > extern void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c); > extern void switch_to_sld(unsigned long tifn); > -extern bool handle_user_split_lock(struct pt_regs *regs, long error_code); > +extern bool handle_user_split_lock(unsigned long ip); > #else > static inline void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c) {} > static inline void switch_to_sld(unsigned long tifn) {} > -static inline bool handle_user_split_lock(struct pt_regs *regs, long error_code) > +static inline bool handle_user_split_lock(unsigned long ip) > { > return false; > } > diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c > index 3eeab717a0d0..c401d174c8db 100644 > --- a/arch/x86/kernel/cpu/intel.c > +++ b/arch/x86/kernel/cpu/intel.c > @@ -1102,13 +1102,13 @@ static void split_lock_init(struct cpuinfo_x86 *c) > sld_state = sld_disable; > } > > -bool handle_user_split_lock(struct pt_regs *regs, long error_code) > +bool handle_user_split_lock(unsigned long ip) > { > - if ((regs->flags & X86_EFLAGS_AC) || sld_state == sld_fatal) > + if (sld_state == sld_fatal) > return false; > > pr_warn_ratelimited("#AC: %s/%d took a split_lock trap at address: 0x%lx\n", > - current->comm, current->pid, regs->ip); > + current->comm, current->pid, ip); > > /* > * Disable the split lock detection for this task so it can make > @@ -1119,6 +1119,7 @@ bool handle_user_split_lock(struct pt_regs *regs, long error_code) > set_tsk_thread_flag(current, TIF_SLD); > return true; > } > +EXPORT_SYMBOL_GPL(handle_user_split_lock); > > /* > * This function is called only when switching between tasks with > diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c > index 0ef5befaed7d..407ff9be610f 100644 > --- a/arch/x86/kernel/traps.c > +++ b/arch/x86/kernel/traps.c > @@ -304,7 +304,7 @@ dotraplinkage void do_alignment_check(struct pt_regs *regs, long error_code) > > local_irq_enable(); > > - if (handle_user_split_lock(regs, error_code)) > + if (!(regs->flags & X86_EFLAGS_AC) && handle_user_split_lock(regs->ip)) > return; > > do_trap(X86_TRAP_AC, SIGBUS, "alignment check", regs, > -- > 2.20.1 > Looks good to me. Reviewed-by: Tony Luck <tony.luck@intel.com>
diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h index ff6f3ca649b3..ff567afa6ee1 100644 --- a/arch/x86/include/asm/cpu.h +++ b/arch/x86/include/asm/cpu.h @@ -43,11 +43,11 @@ unsigned int x86_stepping(unsigned int sig); #ifdef CONFIG_CPU_SUP_INTEL extern void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c); extern void switch_to_sld(unsigned long tifn); -extern bool handle_user_split_lock(struct pt_regs *regs, long error_code); +extern bool handle_user_split_lock(unsigned long ip); #else static inline void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c) {} static inline void switch_to_sld(unsigned long tifn) {} -static inline bool handle_user_split_lock(struct pt_regs *regs, long error_code) +static inline bool handle_user_split_lock(unsigned long ip) { return false; } diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index 3eeab717a0d0..c401d174c8db 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -1102,13 +1102,13 @@ static void split_lock_init(struct cpuinfo_x86 *c) sld_state = sld_disable; } -bool handle_user_split_lock(struct pt_regs *regs, long error_code) +bool handle_user_split_lock(unsigned long ip) { - if ((regs->flags & X86_EFLAGS_AC) || sld_state == sld_fatal) + if (sld_state == sld_fatal) return false; pr_warn_ratelimited("#AC: %s/%d took a split_lock trap at address: 0x%lx\n", - current->comm, current->pid, regs->ip); + current->comm, current->pid, ip); /* * Disable the split lock detection for this task so it can make @@ -1119,6 +1119,7 @@ bool handle_user_split_lock(struct pt_regs *regs, long error_code) set_tsk_thread_flag(current, TIF_SLD); return true; } +EXPORT_SYMBOL_GPL(handle_user_split_lock); /* * This function is called only when switching between tasks with diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 0ef5befaed7d..407ff9be610f 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -304,7 +304,7 @@ dotraplinkage void do_alignment_check(struct pt_regs *regs, long error_code) local_irq_enable(); - if (handle_user_split_lock(regs, error_code)) + if (!(regs->flags & X86_EFLAGS_AC) && handle_user_split_lock(regs->ip)) return; do_trap(X86_TRAP_AC, SIGBUS, "alignment check", regs,
In the future, KVM will use handle_user_split_lock() to handle #AC caused by split lock in guest. Due to the fact that KVM doesn't have a @regs context and will pre-check EFLASG.AC, move the EFLAGS.AC check to do_alignment_check(). Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com> --- arch/x86/include/asm/cpu.h | 4 ++-- arch/x86/kernel/cpu/intel.c | 7 ++++--- arch/x86/kernel/traps.c | 2 +- 3 files changed, 7 insertions(+), 6 deletions(-)