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Commit c11f11fc authored by Frederic Weisbecker's avatar Frederic Weisbecker
Browse files

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: default avatarFrederic 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>
parent 6fac4829

arch/ia64/kernel/time.c

+1 −0
Original line number Diff line number Diff line
@@ -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)

{

arch/powerpc/kernel/time.c

+1 −0
Original line number Diff line number Diff line
@@ -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)

{

include/linux/kvm_host.h

+30 −9
Original line number Diff line number Diff line
@@ -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);

}



/*

include/linux/vtime.h

+0 −2
Original line number Diff line number Diff line
@@ -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; }

kernel/sched/cputime.c

+0 −10
Original line number Diff line number Diff line
@@ -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)

{