KVM: Shove vcpu stats_id init into kvm_vcpu_init()

Initialize stats_id alongside other kvm_vcpu fields to make it more
difficult to unintentionally access stats_id before it's set.

No functional change intended.
Signed-off-by: Oliver Upton <oupton@google.com>
Message-Id: <20220720092259.3491733-3-oliver.upton@linux.dev>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

virt/kvm/kvm_main.c

@@ -484,6 +484,10 @@ static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
 	vcpu->ready = false;
 	preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops);
 	vcpu->last_used_slot = NULL;
+
+	/* Fill the stats id string for the vcpu */
+	snprintf(vcpu->stats_id, sizeof(vcpu->stats_id), "kvm-%d/vcpu-%d",
+		 task_pid_nr(current), id);
 }
 
 static void kvm_vcpu_destroy(struct kvm_vcpu *vcpu)
@@ -3919,10 +3923,6 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
 	if (r)
 		goto unlock_vcpu_destroy;
 
-	/* Fill the stats id string for the vcpu */
-	snprintf(vcpu->stats_id, sizeof(vcpu->stats_id), "kvm-%d/vcpu-%d",
-		 task_pid_nr(current), id);
-
 	/* Now it's all set up, let userspace reach it */
 	kvm_get_kvm(kvm);
 	r = create_vcpu_fd(vcpu);