KVM: Add and use pr_unimpl for standard formatting of unimplemented features

All guest-invokable printks should be ratelimited to prevent malicious
guests from flooding logs.  This is a start.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/drivers/kvm/svm.c b/drivers/kvm/svm.c
index 7beaff1..3ec30d7 100644
--- a/drivers/kvm/svm.c
+++ b/drivers/kvm/svm.c
@@ -1167,7 +1167,7 @@
 static int task_switch_interception(struct vcpu_svm *svm,
 				    struct kvm_run *kvm_run)
 {
-	printk(KERN_DEBUG "%s: task swiche is unsupported\n", __FUNCTION__);
+	pr_unimpl(&svm->vcpu, "%s: task switch is unsupported\n", __FUNCTION__);
 	kvm_run->exit_reason = KVM_EXIT_UNKNOWN;
 	return 0;
 }
@@ -1183,7 +1183,7 @@
 				   struct kvm_run *kvm_run)
 {
 	if (emulate_instruction(&svm->vcpu, NULL, 0, 0) != EMULATE_DONE)
-		printk(KERN_ERR "%s: failed\n", __FUNCTION__);
+		pr_unimpl(&svm->vcpu, "%s: failed\n", __FUNCTION__);
 	return 1;
 }