KVM: arm64: Unregister perf callbacks if hypervisor finalization fails

Undo everything done by init_subsystems() if a later initialization step
fails, i.e. unregister perf callbacks in addition to unregistering the
power management notifier.

Fixes: bfa79a80 ("KVM: arm64: Elevate hypervisor mappings creation at EL2")
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20221130230934.1014142-19-seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/arm64/kvm/arm.c

@@ -1846,12 +1846,21 @@ static int init_subsystems(void)
 	kvm_register_perf_callbacks(NULL);
 
 out:
+	if (err)
+		hyp_cpu_pm_exit();
+
 	if (err || !is_protected_kvm_enabled())
 		on_each_cpu(_kvm_arch_hardware_disable, NULL, 1);
 
 	return err;
 }
 
+static void teardown_subsystems(void)
+{
+	kvm_unregister_perf_callbacks();
+	hyp_cpu_pm_exit();
+}
+
 static void teardown_hyp_mode(void)
 {
 	int cpu;
@@ -2254,7 +2263,7 @@ int kvm_arch_init(void *opaque)
 
 	err = init_subsystems();
 	if (err)
-		goto out_subs;
+		goto out_hyp;
 
 	if (!in_hyp_mode) {
 		err = finalize_hyp_mode();
@@ -2275,7 +2284,7 @@ int kvm_arch_init(void *opaque)
 	return 0;
 
 out_subs:
-	hyp_cpu_pm_exit();
+	teardown_subsystems();
 out_hyp:
 	if (!in_hyp_mode)
 		teardown_hyp_mode();