diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index 76735929b7..e1d04ff20b 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -1994,12 +1994,13 @@ int virQEMUCapsGetMachineTypesCaps(virQEMUCapsPtr qemuCaps,
 {
     size_t i;
 
-    *nmachines = 0;
     *machines = NULL;
-    if (VIR_ALLOC_N(*machines, qemuCaps->nmachineTypes) < 0)
-        goto error;
     *nmachines = qemuCaps->nmachineTypes;
 
+    if (*nmachines &&
+        VIR_ALLOC_N(*machines, qemuCaps->nmachineTypes) < 0)
+        goto error;
+
     for (i = 0; i < qemuCaps->nmachineTypes; i++) {
         virCapsGuestMachinePtr mach;
         if (VIR_ALLOC(mach) < 0)