diff --git a/hw/tpm/tpm_tis.c b/hw/tpm/tpm_tis.c
index d9322692ee..2563d7501f 100644
--- a/hw/tpm/tpm_tis.c
+++ b/hw/tpm/tpm_tis.c
@@ -233,7 +233,7 @@ static void tpm_tis_new_active_locality(TPMState *s, uint8_t new_active_locty)
 }
 
 /* abort -- this function switches the locality */
-static void tpm_tis_abort(TPMState *s, uint8_t locty)
+static void tpm_tis_abort(TPMState *s)
 {
     s->rw_offset = 0;
 
@@ -263,7 +263,9 @@ static void tpm_tis_prep_abort(TPMState *s, uint8_t locty, uint8_t newlocty)
 {
     uint8_t busy_locty;
 
-    s->aborting_locty = locty;
+    assert(TPM_TIS_IS_VALID_LOCTY(newlocty));
+
+    s->aborting_locty = locty; /* may also be TPM_TIS_NO_LOCALITY */
     s->next_locty = newlocty;  /* locality after successful abort */
 
     /*
@@ -281,7 +283,7 @@ static void tpm_tis_prep_abort(TPMState *s, uint8_t locty, uint8_t newlocty)
         }
     }
 
-    tpm_tis_abort(s, locty);
+    tpm_tis_abort(s);
 }
 
 /*
@@ -293,6 +295,8 @@ static void tpm_tis_request_completed(TPMIf *ti, int ret)
     uint8_t locty = s->cmd.locty;
     uint8_t l;
 
+    assert(TPM_TIS_IS_VALID_LOCTY(locty));
+
     if (s->cmd.selftest_done) {
         for (l = 0; l < TPM_TIS_NUM_LOCALITIES; l++) {
             s->loc[l].sts |= TPM_TIS_STS_SELFTEST_DONE;
@@ -311,7 +315,7 @@ static void tpm_tis_request_completed(TPMIf *ti, int ret)
     }
 
     if (TPM_TIS_IS_VALID_LOCTY(s->next_locty)) {
-        tpm_tis_abort(s, locty);
+        tpm_tis_abort(s);
     }
 
     tpm_tis_raise_irq(s, locty,