From ebaac1736245e78109cd47d453a86a18dcfc94b8 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Wed, 15 Jun 2016 15:09:28 +0200 Subject: context_tracking: move rcu_virt_note_context_switch out of kvm_host.h Make kvm_guest_{enter,exit} and __kvm_guest_{enter,exit} trivial wrappers around the code in context_tracking.h. Name the context_tracking.h functions consistently with what those for kernel<->user switch. Cc: Andy Lutomirski Cc: Peter Zijlstra Cc: H. Peter Anvin Cc: Ingo Molnar Cc: Thomas Gleixner Reviewed-by: Rik van Riel Signed-off-by: Paolo Bonzini --- include/linux/context_tracking.h | 38 ++++++++++++++++++++++++++++++++++---- 1 file changed, 34 insertions(+), 4 deletions(-) (limited to 'include/linux/context_tracking.h') diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h index d259274238db..ff4a32d24d56 100644 --- a/include/linux/context_tracking.h +++ b/include/linux/context_tracking.h @@ -84,7 +84,8 @@ static inline void context_tracking_init(void) { } #ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN -static inline void guest_enter(void) +/* must be called with irqs disabled */ +static inline void guest_enter_irqoff(void) { if (vtime_accounting_cpu_enabled()) vtime_guest_enter(current); @@ -93,9 +94,19 @@ static inline void guest_enter(void) if (context_tracking_is_enabled()) __context_tracking_enter(CONTEXT_GUEST); + + /* KVM does not hold any references to rcu protected data when it + * switches CPU into a guest mode. In fact switching to a guest mode + * is very similar to exiting to userspace from rcu point of view. In + * addition CPU may stay in a guest mode for quite a long time (up to + * one time slice). Lets treat guest mode as quiescent state, just like + * we do with user-mode execution. + */ + if (!context_tracking_cpu_is_enabled()) + rcu_virt_note_context_switch(smp_processor_id()); } -static inline void guest_exit(void) +static inline void guest_exit_irqoff(void) { if (context_tracking_is_enabled()) __context_tracking_exit(CONTEXT_GUEST); @@ -107,7 +118,7 @@ static inline void guest_exit(void) } #else -static inline void guest_enter(void) +static inline void guest_enter_irqoff(void) { /* * This is running in ioctl context so its safe @@ -116,9 +127,10 @@ static inline void guest_enter(void) */ vtime_account_system(current); current->flags |= PF_VCPU; + rcu_virt_note_context_switch(smp_processor_id()); } -static inline void guest_exit(void) +static inline void guest_exit_irqoff(void) { /* Flush the guest cputime we spent on the guest */ vtime_account_system(current); @@ -126,4 +138,22 @@ static inline void guest_exit(void) } #endif /* CONFIG_VIRT_CPU_ACCOUNTING_GEN */ +static inline void guest_enter(void) +{ + unsigned long flags; + + local_irq_save(flags); + guest_enter_irqoff(); + local_irq_restore(flags); +} + +static inline void guest_exit(void) +{ + unsigned long flags; + + local_irq_save(flags); + guest_exit_irqoff(); + local_irq_restore(flags); +} + #endif -- cgit v1.2.3