tpm-backend: store TPMIf interface, improve backend_init()

Store the TPM interface, the actual object may be different from
TPMState. Keep a reference on the interface, and check the backend
wasn't already initialized.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>

1 files changed, 9 insertions, 2 deletions

diff --git a/backends/tpm.c b/backends/tpm.c
index 1e416d7..86f0e7e 100644
--- a/backends/tpm.c
+++ b/backends/tpm.c
@@ -43,9 +43,15 @@ enum TpmType tpm_backend_get_type(TPMBackend *s)
     return k->type;
 }
 
-int tpm_backend_init(TPMBackend *s, TPMState *state)
+int tpm_backend_init(TPMBackend *s, TPMIf *tpmif)
 {
-    s->tpm_state = state;
+    if (s->tpmif) {
+        return -1;
+    }
+
+    s->tpmif = tpmif;
+    object_ref(OBJECT(tpmif));
+
     s->had_startup_error = false;
 
     return 0;
@@ -193,6 +199,7 @@ static void tpm_backend_instance_finalize(Object *obj)
 {
     TPMBackend *s = TPM_BACKEND(obj);
 
+    object_unref(OBJECT(s->tpmif));
     g_free(s->id);
     tpm_backend_thread_end(s);
 }