kvm: Prepare to add generic guest entry/exit callbacks

Do some ground preparatory work before adding guest_enter()
and guest_exit() context tracking callbacks. Those will
be later used to read the guest cputime safely when we
run in full dynticks mode.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Gleb Natapov <gleb@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>

5 files changed, 32 insertions, 21 deletions

diff --git a/arch/ia64/kernel/time.c b/arch/ia64/kernel/time.c
index a3a3f5a1cb3a..fbaac1afb844 100644
--- a/arch/ia64/kernel/time.c
+++ b/arch/ia64/kernel/time.c
@@ -136,6 +136,7 @@ void vtime_account_system(struct task_struct *tsk)
 
         account_system_time(tsk, 0, delta, delta);
 }
+EXPORT_SYMBOL_GPL(vtime_account_system);
 
 void vtime_account_idle(struct task_struct *tsk)
 {
diff --git a/arch/powerpc/kernel/time.c b/arch/powerpc/kernel/time.c
index 22c9b67f9983..2e04b37f67f9 100644
--- a/arch/powerpc/kernel/time.c
+++ b/arch/powerpc/kernel/time.c
@@ -347,6 +347,7 @@ void vtime_account_system(struct task_struct *tsk)
         if (stolen)
                 account_steal_time(stolen);
 }
+EXPORT_SYMBOL_GPL(vtime_account_system);
 
 void vtime_account_idle(struct task_struct *tsk)
 {
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 2c497ab0d03d..4fe2396401da 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -22,6 +22,7 @@
 #include <linux/rcupdate.h>
 #include <linux/ratelimit.h>
 #include <linux/err.h>
+#include <linux/irqflags.h>
 #include <asm/signal.h>
 
 #include <linux/kvm.h>
@@ -740,15 +741,36 @@ static inline int kvm_deassign_device(struct kvm *kvm,
 }
 #endif /* CONFIG_IOMMU_API */
 
-static inline void kvm_guest_enter(void)
+static inline void guest_enter(void)
 {
-        BUG_ON(preemptible());
         /*
          * This is running in ioctl context so we can avoid
          * the call to vtime_account() with its unnecessary idle check.
          */
-        vtime_account_system_irqsafe(current);
+        vtime_account_system(current);
         current->flags |= PF_VCPU;
+}
+
+static inline void guest_exit(void)
+{
+        /*
+         * This is running in ioctl context so we can avoid
+         * the call to vtime_account() with its unnecessary idle check.
+         */
+        vtime_account_system(current);
+        current->flags &= ~PF_VCPU;
+}
+
+static inline void kvm_guest_enter(void)
+{
+        unsigned long flags;
+
+        BUG_ON(preemptible());
+
+        local_irq_save(flags);
+        guest_enter();
+        local_irq_restore(flags);
+
         /* 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 userspase from rcu point of view. In
@@ -761,12 +783,11 @@ static inline void kvm_guest_enter(void)
 
 static inline void kvm_guest_exit(void)
 {
-        /*
-         * This is running in ioctl context so we can avoid
-         * the call to vtime_account() with its unnecessary idle check.
-         */
-        vtime_account_system_irqsafe(current);
-        current->flags &= ~PF_VCPU;
+        unsigned long flags;
+
+        local_irq_save(flags);
+        guest_exit();
+        local_irq_restore(flags);
 }
 
 /*
diff --git a/include/linux/vtime.h b/include/linux/vtime.h
index 5368af9bdf06..bb50c3ca0d79 100644
--- a/include/linux/vtime.h
+++ b/include/linux/vtime.h
@@ -6,7 +6,6 @@ struct task_struct;
 #ifdef CONFIG_VIRT_CPU_ACCOUNTING
 extern void vtime_task_switch(struct task_struct *prev);
 extern void vtime_account_system(struct task_struct *tsk);
-extern void vtime_account_system_irqsafe(struct task_struct *tsk);
 extern void vtime_account_idle(struct task_struct *tsk);
 extern void vtime_account_user(struct task_struct *tsk);
 extern void vtime_account(struct task_struct *tsk);
@@ -20,7 +19,6 @@ static inline bool vtime_accounting_enabled(void) { return true; }
 #else /* !CONFIG_VIRT_CPU_ACCOUNTING */
 static inline void vtime_task_switch(struct task_struct *prev) { }
 static inline void vtime_account_system(struct task_struct *tsk) { }
-static inline void vtime_account_system_irqsafe(struct task_struct *tsk) { }
 static inline void vtime_account_user(struct task_struct *tsk) { }
 static inline void vtime_account(struct task_struct *tsk) { }
 static inline bool vtime_accounting_enabled(void) { return false; }
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index c533deaf06d5..a44ecdf809a1 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -465,16 +465,6 @@ void thread_group_cputime_adjusted(struct task_struct *p, cputime_t *ut, cputime
         *st = cputime.stime;
 }
 
-void vtime_account_system_irqsafe(struct task_struct *tsk)
-{
-        unsigned long flags;
-
-        local_irq_save(flags);
-        vtime_account_system(tsk);
-        local_irq_restore(flags);
-}
-EXPORT_SYMBOL_GPL(vtime_account_system_irqsafe);
-
 #ifndef __ARCH_HAS_VTIME_TASK_SWITCH
 void vtime_task_switch(struct task_struct *prev)
 {