From 29bd350bf6a99c61176699d60a827595a471f6e1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=A1n=20Tomko?= <jtomko@redhat.com>
Date: Mon, 29 Apr 2013 20:01:19 +0200
Subject: [PATCH] qemu: report an error if memballoon has wrong address type

qemuBuildMemballoonDevStr returns NULL if memballoon doesn't have
the right address type, but it doesn't report an error, leading to:
error: An error occurred, but the cause is unknown

Report a helpful error message instead, e.g.:
error: XML error: memballoon unsupported with address type 'usb'
---
 src/qemu/qemu_command.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index d161b5672c..3184e5b9c3 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -4175,6 +4175,9 @@ qemuBuildMemballoonDevStr(virDomainMemballoonDefPtr dev,
             virBufferAddLit(&buf, "virtio-balloon-ccw");
             break;
         default:
+            virReportError(VIR_ERR_XML_ERROR,
+                           _("memballoon unsupported with address type '%s'"),
+                           virDomainDeviceAddressTypeToString(dev->info.type));
             goto error;
     }