diff options
| -rw-r--r-- | arch/powerpc/include/asm/kvm_book3s.h | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/traps.c | 2 | ||||
| -rw-r--r-- | include/linux/context_tracking.h | 15 | ||||
| -rw-r--r-- | include/linux/context_tracking_state.h | 9 | ||||
| -rw-r--r-- | include/linux/kvm_host.h | 3 | ||||
| -rw-r--r-- | kernel/context_tracking.c | 59 | ||||
| -rw-r--r-- | kernel/sched/core.c | 2 |
7 files changed, 61 insertions, 33 deletions
diff --git a/arch/powerpc/include/asm/kvm_book3s.h b/arch/powerpc/include/asm/kvm_book3s.h index 942c7b1..9930904 100644 --- a/arch/powerpc/include/asm/kvm_book3s.h +++ b/arch/powerpc/include/asm/kvm_book3s.h @@ -106,10 +106,6 @@ struct kvmppc_vcpu_book3s { spinlock_t mmu_lock; }; -#define CONTEXT_HOST 0 -#define CONTEXT_GUEST 1 -#define CONTEXT_GUEST_END 2 - #define VSID_REAL 0x07ffffffffc00000ULL #define VSID_BAT 0x07ffffffffb00000ULL #define VSID_64K 0x0800000000000000ULL diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index f4fa991..324ab52 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -123,7 +123,7 @@ enum ctx_state ist_enter(struct pt_regs *regs) * but we need to notify RCU. */ rcu_nmi_enter(); - prev_state = IN_KERNEL; /* the value is irrelevant. */ + prev_state = CONTEXT_KERNEL; /* the value is irrelevant. */ } /* diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h index 37b81bd..2821838 100644 --- a/include/linux/context_tracking.h +++ b/include/linux/context_tracking.h @@ -10,6 +10,8 @@ #ifdef CONFIG_CONTEXT_TRACKING extern void context_tracking_cpu_set(int cpu); +extern void context_tracking_enter(enum ctx_state state); +extern void context_tracking_exit(enum ctx_state state); extern void context_tracking_user_enter(void); extern void context_tracking_user_exit(void); extern void __context_tracking_task_switch(struct task_struct *prev, @@ -35,7 +37,8 @@ static inline enum ctx_state exception_enter(void) return 0; prev_ctx = this_cpu_read(context_tracking.state); - context_tracking_user_exit(); + if (prev_ctx != CONTEXT_KERNEL) + context_tracking_exit(prev_ctx); return prev_ctx; } @@ -43,8 +46,8 @@ static inline enum ctx_state exception_enter(void) static inline void exception_exit(enum ctx_state prev_ctx) { if (context_tracking_is_enabled()) { - if (prev_ctx == IN_USER) - context_tracking_user_enter(); + if (prev_ctx != CONTEXT_KERNEL) + context_tracking_enter(prev_ctx); } } @@ -78,10 +81,16 @@ static inline void guest_enter(void) vtime_guest_enter(current); else current->flags |= PF_VCPU; + + if (context_tracking_is_enabled()) + context_tracking_enter(CONTEXT_GUEST); } static inline void guest_exit(void) { + if (context_tracking_is_enabled()) + context_tracking_exit(CONTEXT_GUEST); + if (vtime_accounting_enabled()) vtime_guest_exit(current); else diff --git a/include/linux/context_tracking_state.h b/include/linux/context_tracking_state.h index 97a8122..6b7b96a 100644 --- a/include/linux/context_tracking_state.h +++ b/include/linux/context_tracking_state.h @@ -13,8 +13,9 @@ struct context_tracking { */ bool active; enum ctx_state { - IN_KERNEL = 0, - IN_USER, + CONTEXT_KERNEL = 0, + CONTEXT_USER, + CONTEXT_GUEST, } state; }; @@ -34,11 +35,13 @@ static inline bool context_tracking_cpu_is_enabled(void) static inline bool context_tracking_in_user(void) { - return __this_cpu_read(context_tracking.state) == IN_USER; + return __this_cpu_read(context_tracking.state) == CONTEXT_USER; } #else static inline bool context_tracking_in_user(void) { return false; } static inline bool context_tracking_active(void) { return false; } +static inline bool context_tracking_is_enabled(void) { return false; } +static inline bool context_tracking_cpu_is_enabled(void) { return false; } #endif /* CONFIG_CONTEXT_TRACKING */ #endif diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index 82af5d0..ad45054 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -779,7 +779,8 @@ static inline void kvm_guest_enter(void) * one time slice). Lets treat guest mode as quiescent state, just like * we do with user-mode execution. */ - rcu_virt_note_context_switch(smp_processor_id()); + if (!context_tracking_cpu_is_enabled()) + rcu_virt_note_context_switch(smp_processor_id()); } static inline void kvm_guest_exit(void) diff --git a/kernel/context_tracking.c b/kernel/context_tracking.c index 937ecdf..72d59a1 100644 --- a/kernel/context_tracking.c +++ b/kernel/context_tracking.c @@ -39,15 +39,15 @@ void context_tracking_cpu_set(int cpu) } /** - * context_tracking_user_enter - Inform the context tracking that the CPU is going to - * enter userspace mode. + * context_tracking_enter - Inform the context tracking that the CPU is going + * enter user or guest space mode. * * This function must be called right before we switch from the kernel - * to userspace, when it's guaranteed the remaining kernel instructions - * to execute won't use any RCU read side critical section because this - * function sets RCU in extended quiescent state. + * to user or guest space, when it's guaranteed the remaining kernel + * instructions to execute won't use any RCU read side critical section + * because this function sets RCU in extended quiescent state. */ -void context_tracking_user_enter(void) +void context_tracking_enter(enum ctx_state state) { unsigned long flags; @@ -75,9 +75,8 @@ void context_tracking_user_enter(void) WARN_ON_ONCE(!current->mm); local_irq_save(flags); - if ( __this_cpu_read(context_tracking.state) != IN_USER) { + if ( __this_cpu_read(context_tracking.state) != state) { if (__this_cpu_read(context_tracking.active)) { - trace_user_enter(0); /* * At this stage, only low level arch entry code remains and * then we'll run in userspace. We can assume there won't be @@ -85,7 +84,10 @@ void context_tracking_user_enter(void) * user_exit() or rcu_irq_enter(). Let's remove RCU's dependency * on the tick. */ - vtime_user_enter(current); + if (state == CONTEXT_USER) { + trace_user_enter(0); + vtime_user_enter(current); + } rcu_user_enter(); } /* @@ -101,24 +103,32 @@ void context_tracking_user_enter(void) * OTOH we can spare the calls to vtime and RCU when context_tracking.active * is false because we know that CPU is not tickless. */ - __this_cpu_write(context_tracking.state, IN_USER); + __this_cpu_write(context_tracking.state, state); } local_irq_restore(flags); } +NOKPROBE_SYMBOL(context_tracking_enter); +EXPORT_SYMBOL_GPL(context_tracking_enter); + +void context_tracking_user_enter(void) +{ + context_tracking_enter(CONTEXT_USER); +} NOKPROBE_SYMBOL(context_tracking_user_enter); /** - * context_tracking_user_exit - Inform the context tracking that the CPU is - * exiting userspace mode and entering the kernel. + * context_tracking_exit - Inform the context tracking that the CPU is + * exiting user or guest mode and entering the kernel. * - * This function must be called after we entered the kernel from userspace - * before any use of RCU read side critical section. This potentially include - * any high level kernel code like syscalls, exceptions, signal handling, etc... + * This function must be called after we entered the kernel from user or + * guest space before any use of RCU read side critical section. This + * potentially include any high level kernel code like syscalls, exceptions, + * signal handling, etc... * * This call supports re-entrancy. This way it can be called from any exception * handler without needing to know if we came from userspace or not. */ -void context_tracking_user_exit(void) +void context_tracking_exit(enum ctx_state state) { unsigned long flags; @@ -129,20 +139,29 @@ void context_tracking_user_exit(void) return; local_irq_save(flags); - if (__this_cpu_read(context_tracking.state) == IN_USER) { + if (__this_cpu_read(context_tracking.state) == state) { if (__this_cpu_read(context_tracking.active)) { /* * We are going to run code that may use RCU. Inform * RCU core about that (ie: we may need the tick again). */ rcu_user_exit(); - vtime_user_exit(current); - trace_user_exit(0); + if (state == CONTEXT_USER) { + vtime_user_exit(current); + trace_user_exit(0); + } } - __this_cpu_write(context_tracking.state, IN_KERNEL); + __this_cpu_write(context_tracking.state, CONTEXT_KERNEL); } local_irq_restore(flags); } +NOKPROBE_SYMBOL(context_tracking_exit); +EXPORT_SYMBOL_GPL(context_tracking_exit); + +void context_tracking_user_exit(void) +{ + context_tracking_exit(CONTEXT_USER); +} NOKPROBE_SYMBOL(context_tracking_user_exit); /** diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 2f7937e..f9123a8 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -2853,7 +2853,7 @@ asmlinkage __visible void __sched schedule_user(void) * we find a better solution. * * NB: There are buggy callers of this function. Ideally we - * should warn if prev_state != IN_USER, but that will trigger + * should warn if prev_state != CONTEXT_USER, but that will trigger * too frequently to make sense yet. */ enum ctx_state prev_state = exception_enter(); |
