Merge branch 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull NOHZ changes from Ingo Molnar:
 "This tree adds full dynticks support to KVM guests (support the
  disabling of the timer tick on the guest).  The main missing piece was
  the recognition of guest execution as RCU extended quiescent state and
  related changes"

* 'timers-nohz-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  kvm,rcu,nohz: use RCU extended quiescent state when running KVM guest
  context_tracking: Export context_tracking_user_enter/exit
  context_tracking: Run vtime_user_enter/exit only when state == CONTEXT_USER
  context_tracking: Add stub context_tracking_is_enabled
  context_tracking: Generalize context tracking APIs to support user and guest
  context_tracking: Rename context symbols to prepare for transition state
  ppc: Remove unused cpp symbols in kvm headers

3 files changed, 20 insertions, 7 deletions

diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
index 37b81bd51ec0..2821838256b4 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 97a81225d037..6b7b96a32b75 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 82af5d0b996e..ad45054309a0 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)