qemu: Improve error if setmem fails for lacking of balloon support

"cannot set memory of an active domain" is misleading, it sounds
like setting memory of active domain is not supported.

diff --git a/src/qemu/qemu_driver.c b/src/qemu/qemu_driver.c
index 2177c3096d3598da90814c4ad0e1a7bd3200b0d7..2f934040ea7d996574ac447498a195d440ec0783 100644 (file)
--- a/src/qemu/qemu_driver.c
+++ b/src/qemu/qemu_driver.c
@@ -2037,7 +2037,8 @@ static int qemudDomainSetMemoryFlags(virDomainPtr dom, unsigned long newmem,
             /* Lack of balloon support is a fatal error */
             if (r == 0) {
                 qemuReportError(VIR_ERR_OPERATION_INVALID, "%s",
-                                _("cannot set memory of an active domain"));
+                                _("Unable to change memory of active domain without "
+                                  "the balloon device and guest OS balloon driver"));
                 goto endjob;
             }
         }