diff --git a/src/conf/domain_addr.c b/src/conf/domain_addr.c
index ef7ee80e6a..607ba56efd 100644
--- a/src/conf/domain_addr.c
+++ b/src/conf/domain_addr.c
@@ -1007,6 +1007,13 @@ virZPCIAddrKeyCopy(const void *name)
 }
 
 
+static char *
+virZPCIAddrKeyPrintHuman(const void *name)
+{
+    return g_strdup_printf("%u", *((unsigned int *)name));
+}
+
+
 static void
 virZPCIAddrKeyFree(void *name)
 {
@@ -1041,6 +1048,7 @@ virDomainPCIAddressSetExtensionAlloc(virDomainPCIAddressSetPtr addrs,
                                                        virZPCIAddrKeyCode,
                                                        virZPCIAddrKeyEqual,
                                                        virZPCIAddrKeyCopy,
+                                                       virZPCIAddrKeyPrintHuman,
                                                        virZPCIAddrKeyFree)))
             goto error;
 
@@ -1048,6 +1056,7 @@ virDomainPCIAddressSetExtensionAlloc(virDomainPCIAddressSetPtr addrs,
                                                        virZPCIAddrKeyCode,
                                                        virZPCIAddrKeyEqual,
                                                        virZPCIAddrKeyCopy,
+                                                       virZPCIAddrKeyPrintHuman,
                                                        virZPCIAddrKeyFree)))
             goto error;
     }
diff --git a/src/util/vircgroup.c b/src/util/vircgroup.c
index 87ed9f4565..dff2f6fd3a 100644
--- a/src/util/vircgroup.c
+++ b/src/util/vircgroup.c
@@ -2502,6 +2502,13 @@ virCgroupPidCopy(const void *name)
 }
 
 
+static char *
+virCgroupPidPrintHuman(const void *name)
+{
+    return g_strdup_printf("%ld", (const long)name);
+}
+
+
 int
 virCgroupKillRecursiveInternal(virCgroupPtr group,
                                int signum,
@@ -2587,6 +2594,7 @@ virCgroupKillRecursive(virCgroupPtr group, int signum)
                                              virCgroupPidCode,
                                              virCgroupPidEqual,
                                              virCgroupPidCopy,
+                                             virCgroupPidPrintHuman,
                                              NULL);
 
     VIR_DEBUG("group=%p path=%s signum=%d", group, group->path, signum);
diff --git a/src/util/virhash.c b/src/util/virhash.c
index 313ca57a54..edf11e8b7a 100644
--- a/src/util/virhash.c
+++ b/src/util/virhash.c
@@ -59,6 +59,7 @@ struct _virHashTable {
     virHashKeyCode keyCode;
     virHashKeyEqual keyEqual;
     virHashKeyCopy keyCopy;
+    virHashKeyPrintHuman keyPrint;
     virHashKeyFree keyFree;
 };
 
@@ -98,6 +99,14 @@ static void *virHashStrCopy(const void *name)
     return ret;
 }
 
+
+static char *
+virHashStrPrintHuman(const void *name)
+{
+    return g_strdup(name);
+}
+
+
 static void virHashStrFree(void *name)
 {
     VIR_FREE(name);
@@ -136,6 +145,7 @@ virHashTablePtr virHashCreateFull(ssize_t size,
                                   virHashKeyCode keyCode,
                                   virHashKeyEqual keyEqual,
                                   virHashKeyCopy keyCopy,
+                                  virHashKeyPrintHuman keyPrint,
                                   virHashKeyFree keyFree)
 {
     virHashTablePtr table = NULL;
@@ -153,6 +163,7 @@ virHashTablePtr virHashCreateFull(ssize_t size,
     table->keyCode = keyCode;
     table->keyEqual = keyEqual;
     table->keyCopy = keyCopy;
+    table->keyPrint = keyPrint;
     table->keyFree = keyFree;
 
     if (VIR_ALLOC_N(table->table, size) < 0) {
@@ -180,6 +191,7 @@ virHashNew(virHashDataFree dataFree)
                              virHashStrCode,
                              virHashStrEqual,
                              virHashStrCopy,
+                             virHashStrPrintHuman,
                              virHashStrFree);
 }
 
@@ -200,6 +212,7 @@ virHashTablePtr virHashCreate(ssize_t size, virHashDataFree dataFree)
                              virHashStrCode,
                              virHashStrEqual,
                              virHashStrCopy,
+                             virHashStrPrintHuman,
                              virHashStrFree);
 }
 
@@ -353,8 +366,13 @@ virHashAddOrUpdateEntry(virHashTablePtr table, const void *name,
                 entry->payload = userdata;
                 return 0;
             } else {
-                virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
-                               _("Duplicate key"));
+                g_autofree char *keystr = NULL;
+
+                if (table->keyPrint)
+                    keystr = table->keyPrint(name);
+
+                virReportError(VIR_ERR_INTERNAL_ERROR,
+                               _("Duplicate hash table key '%s'"), NULLSTR(keystr));
                 return -1;
             }
         }
diff --git a/src/util/virhash.h b/src/util/virhash.h
index 6318c0b3cd..08f99d8a3d 100644
--- a/src/util/virhash.h
+++ b/src/util/virhash.h
@@ -86,6 +86,18 @@ typedef bool (*virHashKeyEqual)(const void *namea, const void *nameb);
  * Returns a newly allocated copy of @name
  */
 typedef void *(*virHashKeyCopy)(const void *name);
+/**
+ * virHashKeyPrintHuman:
+ * @name: the hash key
+ *
+ * Get a human readable version of the key for error messages. Caller
+ * will free the returned string.
+ *
+ * Returns a string representation of the key for use in error messages. Caller
+ * promises to always free the returned string.
+ */
+typedef char *(*virHashKeyPrintHuman) (const void *name);
+
 /**
  * virHashKeyFree:
  * @name: the hash key
@@ -108,6 +120,7 @@ virHashTablePtr virHashCreateFull(ssize_t size,
                                   virHashKeyCode keyCode,
                                   virHashKeyEqual keyEqual,
                                   virHashKeyCopy keyCopy,
+                                  virHashKeyPrintHuman keyPrint,
                                   virHashKeyFree keyFree);
 void virHashFree(virHashTablePtr table);
 ssize_t virHashSize(const virHashTable *table);