diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
index 8804d3d493..1a61701c49 100644
--- a/src/qemu/qemu_hotplug.c
+++ b/src/qemu/qemu_hotplug.c
@@ -607,16 +607,10 @@ qemuDomainAttachSCSIDisk(virConnectPtr conn,
         goto error;
     }
 
-    if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE)) {
-        if (qemuAssignDeviceDiskAlias(vm->def, disk, priv->qemuCaps) < 0)
-            goto error;
-        if (!(devstr = qemuBuildDriveDevStr(vm->def, disk, 0, priv->qemuCaps)))
-            goto error;
-    }
-
-    if (!(drivestr = qemuBuildDriveStr(conn, disk, false, priv->qemuCaps)))
-        goto error;
-
+    /* Let's make sure our disk has a controller defined and loaded
+     * before trying add the disk. The controller the disk is going
+     * to use must exist before a qemu command line string is generated.
+     */
     for (i = 0; i <= disk->info.addr.drive.controller; i++) {
         cont = qemuDomainFindOrCreateSCSIDiskController(driver, vm, i);
         if (!cont)
@@ -628,6 +622,16 @@ qemuDomainAttachSCSIDisk(virConnectPtr conn,
        and hence the above loop must iterate at least once.  */
     sa_assert(cont);
 
+    if (virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE)) {
+        if (qemuAssignDeviceDiskAlias(vm->def, disk, priv->qemuCaps) < 0)
+            goto error;
+        if (!(devstr = qemuBuildDriveDevStr(vm->def, disk, 0, priv->qemuCaps)))
+            goto error;
+    }
+
+    if (!(drivestr = qemuBuildDriveStr(conn, disk, false, priv->qemuCaps)))
+        goto error;
+
     if (VIR_REALLOC_N(vm->def->disks, vm->def->ndisks+1) < 0)
         goto error;