context_tracing: Fix guest accounting with native vtime
1) If context tracking is enabled with native vtime accounting (which combo is useless except for dev testing), we call vtime_guest_enter() and vtime_guest_exit() on host <-> guest switches. But those are stubs in this configurations. As a result, cputime is not correctly flushed on kvm context switches. 2) If context tracking runs but is disabled on some CPUs, those CPUs end up calling __guest_enter/__guest_exit which in turn call vtime_account_system(). We don't want to call this because we run in tick based accounting for these CPUs. Refactor the guest_enter/guest_exit code such that all combinations finally work. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Li Zhong <zhong@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Kevin Hilman <khilman@linaro.org>
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@ -20,25 +20,6 @@ struct context_tracking {
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} state;
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};
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static inline void __guest_enter(void)
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{
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/*
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* This is running in ioctl context so we can avoid
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* the call to vtime_account() with its unnecessary idle check.
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*/
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vtime_account_system(current);
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current->flags |= PF_VCPU;
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}
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static inline void __guest_exit(void)
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{
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/*
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* This is running in ioctl context so we can avoid
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* the call to vtime_account() with its unnecessary idle check.
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*/
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vtime_account_system(current);
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current->flags &= ~PF_VCPU;
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}
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#ifdef CONFIG_CONTEXT_TRACKING
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DECLARE_PER_CPU(struct context_tracking, context_tracking);
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@ -56,9 +37,6 @@ static inline bool context_tracking_active(void)
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extern void user_enter(void);
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extern void user_exit(void);
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extern void guest_enter(void);
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extern void guest_exit(void);
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static inline enum ctx_state exception_enter(void)
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{
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enum ctx_state prev_ctx;
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@ -81,21 +59,35 @@ extern void context_tracking_task_switch(struct task_struct *prev,
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static inline bool context_tracking_in_user(void) { return false; }
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static inline void user_enter(void) { }
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static inline void user_exit(void) { }
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static inline void guest_enter(void)
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{
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__guest_enter();
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}
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static inline void guest_exit(void)
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{
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__guest_exit();
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}
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static inline enum ctx_state exception_enter(void) { return 0; }
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static inline void exception_exit(enum ctx_state prev_ctx) { }
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static inline void context_tracking_task_switch(struct task_struct *prev,
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struct task_struct *next) { }
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#endif /* !CONFIG_CONTEXT_TRACKING */
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#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
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extern void guest_enter(void);
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extern void guest_exit(void);
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#else
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static inline void guest_enter(void)
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{
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/*
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* This is running in ioctl context so we can avoid
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* the call to vtime_account() with its unnecessary idle check.
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*/
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vtime_account_system(current);
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current->flags |= PF_VCPU;
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}
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static inline void guest_exit(void)
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{
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/*
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* This is running in ioctl context so we can avoid
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* the call to vtime_account() with its unnecessary idle check.
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*/
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vtime_account_system(current);
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current->flags &= ~PF_VCPU;
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}
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#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
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#endif
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@ -141,12 +141,13 @@ void user_exit(void)
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local_irq_restore(flags);
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}
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#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN
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void guest_enter(void)
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{
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if (vtime_accounting_enabled())
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vtime_guest_enter(current);
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else
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__guest_enter();
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current->flags |= PF_VCPU;
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}
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EXPORT_SYMBOL_GPL(guest_enter);
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@ -155,9 +156,10 @@ void guest_exit(void)
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if (vtime_accounting_enabled())
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vtime_guest_exit(current);
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else
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__guest_exit();
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current->flags &= ~PF_VCPU;
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}
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EXPORT_SYMBOL_GPL(guest_exit);
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#endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */
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/**
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