From: Rik van Riel <[email protected]> The host kernel is not doing anything while the CPU is executing a KVM guest VCPU, so it can be marked as being in an extended quiescent state, identical to that used when running user space code.
The only exception to that rule is when the host handles an interrupt, which is already handled by the irq code, which calls rcu_irq_enter and rcu_irq_exit. The guest_enter and guest_exit functions already switch vtime accounting independent of context tracking. Leave those calls where they are, instead of moving them into the context tracking code. Reviewed-by: Paul E. McKenney <[email protected]> Signed-off-by: Rik van Riel <[email protected]> Cc: Paul E. McKenney <[email protected]> Cc: Andy Lutomirski <[email protected]> Cc: Will deacon <[email protected]> Cc: Marcelo Tosatti <[email protected]> Cc: Christian Borntraeger <[email protected]> Cc: Luiz Capitulino <[email protected]> Cc: Paolo Bonzini <[email protected]> Signed-off-by: Frederic Weisbecker <[email protected]> --- include/linux/context_tracking.h | 6 ++++++ include/linux/context_tracking_state.h | 1 + include/linux/kvm_host.h | 3 ++- 3 files changed, 9 insertions(+), 1 deletion(-) diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h index 7f1810a..2821838 100644 --- a/include/linux/context_tracking.h +++ b/include/linux/context_tracking.h @@ -81,10 +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 ad44585..6b7b96a 100644 --- a/include/linux/context_tracking_state.h +++ b/include/linux/context_tracking_state.h @@ -15,6 +15,7 @@ struct context_tracking { enum ctx_state { CONTEXT_KERNEL = 0, CONTEXT_USER, + CONTEXT_GUEST, } state; }; diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index d12b210..cc8c61c 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h @@ -766,7 +766,8 @@ 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) -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
