sched: guest CPU accounting: maintain guest state in KVM

Modify KVM to update guest time accounting.

[ mingo@elte.hu: ported to 2.6.24 KVM. ]
Signed-off-by: Laurent Vivier <Laurent.Vivier@bull.net>
Acked-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

drivers/kvm/kvm.h

@@ -624,6 +624,16 @@ void kvm_mmu_unload(struct kvm_vcpu *vcpu);
 
 int kvm_hypercall(struct kvm_vcpu *vcpu, struct kvm_run *run);
 
+static inline void kvm_guest_enter(void)
+{
+	current->flags |= PF_VCPU;
+}
+
+static inline void kvm_guest_exit(void)
+{
+	current->flags &= ~PF_VCPU;
+}
+
 static inline int kvm_mmu_page_fault(struct kvm_vcpu *vcpu, gva_t gva,
 				     u32 error_code)
 {

drivers/kvm/kvm_main.c

@@ -2046,6 +2046,7 @@ again:
 		kvm_x86_ops->inject_pending_vectors(vcpu, kvm_run);
 
 	vcpu->guest_mode = 1;
+	kvm_guest_enter();
 
 	if (vcpu->requests)
 		if (test_and_clear_bit(KVM_TLB_FLUSH, &vcpu->requests))
@@ -2053,6 +2054,7 @@ again:
 
 	kvm_x86_ops->run(vcpu, kvm_run);
 
+	kvm_guest_exit();
 	vcpu->guest_mode = 0;
 	local_irq_enable();