KVM: Use cond_resched() directly and remove useless kvm_resched()

Since the commit 15ad7146 ("KVM: Use the scheduler preemption notifiers
to make kvm preemptible"), the remaining stuff in this function is a
simple cond_resched() call with an extra need_resched() check which was
there to avoid dropping VCPUs unnecessarily.  Now it is meaningless.
Signed-off-by: NTakuya Yoshikawa <yoshikawa_takuya_b1@lab.ntt.co.jp>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>

arch/ia64/kvm/kvm-ia64.c

@@ -702,7 +702,7 @@ static int __vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
 out:
 	srcu_read_unlock(&vcpu->kvm->srcu, idx);
 	if (r > 0) {
-		kvm_resched(vcpu);
+		cond_resched();
 		idx = srcu_read_lock(&vcpu->kvm->srcu);
 		goto again;
 	}

arch/powerpc/kvm/book3s_hv.c

@@ -1348,7 +1348,7 @@ static void kvmppc_run_core(struct kvmppc_vcore *vc)
 	kvm_guest_exit();
 
 	preempt_enable();
-	kvm_resched(vcpu);
+	cond_resched();
 
 	spin_lock(&vc->lock);
 	now = get_tb();

arch/x86/kvm/x86.c

@@ -6125,7 +6125,7 @@ static int __vcpu_run(struct kvm_vcpu *vcpu)
 		}
 		if (need_resched()) {
 			srcu_read_unlock(&kvm->srcu, vcpu->srcu_idx);
-			kvm_resched(vcpu);
+			cond_resched();
 			vcpu->srcu_idx = srcu_read_lock(&kvm->srcu);
 		}
 	}

include/linux/kvm_host.h

@@ -583,7 +583,6 @@ void kvm_vcpu_block(struct kvm_vcpu *vcpu);
 void kvm_vcpu_kick(struct kvm_vcpu *vcpu);
 bool kvm_vcpu_yield_to(struct kvm_vcpu *target);
 void kvm_vcpu_on_spin(struct kvm_vcpu *vcpu);
-void kvm_resched(struct kvm_vcpu *vcpu);
 void kvm_load_guest_fpu(struct kvm_vcpu *vcpu);
 void kvm_put_guest_fpu(struct kvm_vcpu *vcpu);
 

virt/kvm/kvm_main.c

@@ -1710,14 +1710,6 @@ void kvm_vcpu_kick(struct kvm_vcpu *vcpu)
 EXPORT_SYMBOL_GPL(kvm_vcpu_kick);
 #endif /* !CONFIG_S390 */
 
-void kvm_resched(struct kvm_vcpu *vcpu)
-{
-	if (!need_resched())
-		return;
-	cond_resched();
-}
-EXPORT_SYMBOL_GPL(kvm_resched);
-
 bool kvm_vcpu_yield_to(struct kvm_vcpu *target)
 {
 	struct pid *pid;