cpu_x86: Make sure CPU model names are unique in cpu_map

Having multiple CPU model definitions with the same name could result in
unexpected behavior.
Signed-off-by: NJiri Denemark <jdenemar@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

src/cpu/cpu_x86.c

@@ -1293,9 +1293,15 @@ x86ModelParse(xmlXPathContextPtr ctxt,
               void *data)
 {
     virCPUx86MapPtr map = data;
-    virCPUx86ModelPtr model;
+    virCPUx86ModelPtr model = NULL;
     int ret = -1;
 
+    if (x86ModelFind(map, name)) {
+        virReportError(VIR_ERR_INTERNAL_ERROR,
+                       _("Multiple definitions of CPU model '%s'"), name);
+        goto cleanup;
+    }
+
     if (!(model = x86ModelNew()))
         goto cleanup;