target-i386: Require APIC ID to be explicitly set before CPU realize

Instead of setting APIC ID automatically when creating a X86CPU, require
the property to be set before realizing the object (which all callers of
cpu_x86_create() already do).
Reviewed-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>

target-i386/cpu-qom.h

@@ -93,7 +93,7 @@ typedef struct X86CPU {
     bool expose_kvm;
     bool migratable;
     bool host_features;
-    uint32_t apic_id;
+    int64_t apic_id;
 
     /* if true the CPUID code directly forward host cache leaves to the guest */
     bool cache_info_passthrough;

target-i386/cpu.c

@@ -2767,6 +2767,11 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp)
     Error *local_err = NULL;
     static bool ht_warned;
 
+    if (cpu->apic_id < 0) {
+        error_setg(errp, "apic-id property was not initialized properly");
+        return;
+    }
+
     if (env->features[FEAT_7_0_EBX] && env->cpuid_level < 7) {
         env->cpuid_level = 7;
     }
@@ -2910,7 +2915,7 @@ static void x86_cpu_initfn(Object *obj)
                         NULL, NULL, (void *)cpu->filtered_features, NULL);
 
     cpu->hyperv_spinlock_attempts = HYPERV_SPINLOCK_NEVER_RETRY;
-    cpu->apic_id = x86_cpu_apic_id_from_index(cs->cpu_index);
+    cpu->apic_id = -1;
 
     x86_cpu_load_def(cpu, xcc->cpu_def, &error_abort);