diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index e5c355eb19..50d1d94935 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -13717,8 +13717,8 @@ virDomainControllerFind(const virDomainDef *def,
 }
 
 
-static int
-virDomainControllerFindUnusedIndex(virDomainDefPtr def, int type)
+int
+virDomainControllerFindUnusedIndex(virDomainDef const *def, int type)
 {
     int idx = 0;
 
diff --git a/src/conf/domain_conf.h b/src/conf/domain_conf.h
index 0cc82d8116..0d97003a91 100644
--- a/src/conf/domain_conf.h
+++ b/src/conf/domain_conf.h
@@ -2755,6 +2755,7 @@ int virDomainControllerFind(const virDomainDef *def, int type, int idx);
 int virDomainControllerFindByType(virDomainDefPtr def, int type);
 int virDomainControllerFindByPCIAddress(virDomainDefPtr def,
                                         virPCIDeviceAddressPtr addr);
+int virDomainControllerFindUnusedIndex(virDomainDef const *def, int type);
 virDomainControllerDefPtr virDomainControllerRemove(virDomainDefPtr def, size_t i);
 const char *virDomainControllerAliasFind(const virDomainDef *def,
                                          int type, int idx)
diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index fb5b419d1f..e325168e53 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -189,6 +189,7 @@ virDomainControllerDefFree;
 virDomainControllerDefNew;
 virDomainControllerFind;
 virDomainControllerFindByType;
+virDomainControllerFindUnusedIndex;
 virDomainControllerInsert;
 virDomainControllerInsertPreAlloced;
 virDomainControllerModelPCITypeToString;