diff --git a/src/xen/xen_driver.c b/src/xen/xen_driver.c
index ddbfa7a3e4..56ba41b36c 100644
--- a/src/xen/xen_driver.c
+++ b/src/xen/xen_driver.c
@@ -1588,7 +1588,8 @@ xenUnifiedDomainSetSchedulerParameters (virDomainPtr dom,
     GET_PRIVATE(dom->conn);
     int i, ret;
 
-    for (i = 0; i < XEN_UNIFIED_NR_DRIVERS; ++i) {
+    /* do the hypervisor call last to get better error */
+    for (i = XEN_UNIFIED_NR_DRIVERS - 1; i >= 0; i--) {
         if (priv->opened[i] && drivers[i]->domainSetSchedulerParameters) {
            ret = drivers[i]->domainSetSchedulerParameters(dom, params, nparams);
            if (ret == 0)
diff --git a/src/xen/xen_hypervisor.c b/src/xen/xen_hypervisor.c
index 67d0f4b9b5..6246513dc4 100644
--- a/src/xen/xen_hypervisor.c
+++ b/src/xen/xen_hypervisor.c
@@ -1394,8 +1394,8 @@ xenHypervisorSetSchedulerParameters(virDomainPtr domain,
                 } else if (STREQ (params[i].field, str_cap) &&
                     params[i].type == VIR_DOMAIN_SCHED_FIELD_UINT) {
                     val = params[i].value.ui;
-                    if (val > USHRT_MAX) {
-                        snprintf(buf, sizeof(buf), _("Credit scheduler cap parameter (%d) is out of range (0-65535)"), val);
+                    if (val >= USHRT_MAX) {
+                        snprintf(buf, sizeof(buf), _("Credit scheduler cap parameter (%d) is out of range (0-65534)"), val);
                         virXenErrorFunc(VIR_ERR_INVALID_ARG, __FUNCTION__, buf, val);
                         return(-1);
                     }