spapr: fix check of cpu alias name in spapr_get_cpu_core_type()

If the user passes an alias name and a property to -cpu, QEMU fails to
find the CPU definition and exits.

$ qemu-system-ppc64 -cpu POWER8E,compat=power7
qemu-system-ppc64: Unable to find sPAPR CPU Core definition

This happens because spapr_get_cpu_core_type() passes the full string from
the command line (i.e. "POWER8E,compat=power7") to ppc_cpu_lookup_alias(),
instead of the alias name piece only (i.e. "POWER8E").

The fix is to pass model_pieces[0] to ppc_cpu_lookup_alias().
Signed-off-by: NGreg Kurz <groug@kaod.org>
Reviewed-by: NBharata B Rao <bharata@linux.vnet.ibm.com>
Signed-off-by: NDavid Gibson <david@gibson.dropbear.id.au>

hw/ppc/spapr_cpu_core.c

@@ -92,20 +92,20 @@ char *spapr_get_cpu_core_type(const char *model)
     gchar **model_pieces = g_strsplit(model, ",", 2);
 
     core_type = g_strdup_printf("%s-%s", model_pieces[0], TYPE_SPAPR_CPU_CORE);
-    g_strfreev(model_pieces);
 
     /* Check whether it exists or whether we have to look up an alias name */
     if (!object_class_by_name(core_type)) {
         const char *realmodel;
 
         g_free(core_type);
-        realmodel = ppc_cpu_lookup_alias(model);
+        core_type = NULL;
+        realmodel = ppc_cpu_lookup_alias(model_pieces[0]);
         if (realmodel) {
-            return spapr_get_cpu_core_type(realmodel);
+            core_type = spapr_get_cpu_core_type(realmodel);
         }
-        return NULL;
     }
 
+    g_strfreev(model_pieces);
     return core_type;
 }