Restrict MachineClass::valid_cpu_types[] to the single
valid CPU types.

Instead of ignoring invalid CPU type requested by the user:

  $ qemu-system-arm -M midway -cpu cortex-a7 -S -monitor stdio
  QEMU 8.2.50 monitor - type 'help' for more information
  (qemu) info qom-tree
  /machine (midway-machine)
    /cpu[0] (cortex-a15-arm-cpu)
    ...

we now display an error:

  $ qemu-system-arm -M midway -cpu cortex-a7
  qemu-system-arm: Invalid CPU model: cortex-a7
  The only valid type is: cortex-a15

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Gavin Shan <gshan@redhat.com>
---
 hw/arm/highbank.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/hw/arm/highbank.c b/hw/arm/highbank.c
index b8d702c82c..0367050697 100644
--- a/hw/arm/highbank.c
+++ b/hw/arm/highbank.c
@@ -345,10 +345,15 @@ static void midway_init(MachineState *machine)
 
 static void highbank_class_init(ObjectClass *oc, void *data)
 {
+    static const char * const valid_cpu_types[] = {
+        ARM_CPU_TYPE_NAME("cortex-a9"),
+        NULL
+    };
     MachineClass *mc = MACHINE_CLASS(oc);
 
     mc->desc = "Calxeda Highbank (ECX-1000)";
     mc->init = highbank_init;
+    mc->valid_cpu_types = valid_cpu_types;
     mc->block_default_type = IF_IDE;
     mc->units_per_default_bus = 1;
     mc->max_cpus = 4;
@@ -364,10 +369,15 @@ static const TypeInfo highbank_type = {
 
 static void midway_class_init(ObjectClass *oc, void *data)
 {
+    static const char * const valid_cpu_types[] = {
+        ARM_CPU_TYPE_NAME("cortex-a15"),
+        NULL
+    };
     MachineClass *mc = MACHINE_CLASS(oc);
 
     mc->desc = "Calxeda Midway (ECX-2000)";
     mc->init = midway_init;
+    mc->valid_cpu_types = valid_cpu_types;
     mc->block_default_type = IF_IDE;
     mc->units_per_default_bus = 1;
     mc->max_cpus = 4;
-- 
2.41.0