i386: Add die-level cpu topology to x86CPU on PCMachine

The die-level as the first PC-specific cpu topology is added to the leagcy
cpu topology model, which has one die per package implicitly and only the
numbers of sockets/cores/threads are configurable.

In the new model with die-level support, the total number of logical
processors (including offline) on board will be calculated as:

     #cpus = #sockets * #dies * #cores * #threads

and considering compatibility, the default value for #dies would be
initialized to one in x86_cpu_initfn() and pc_machine_initfn().

Signed-off-by: Like Xu <like.xu@linux.intel.com>
Message-Id: <20190612084104.34984-2-like.xu@linux.intel.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

target/i386/cpu.c

@@ -5639,6 +5639,7 @@ static void x86_cpu_initfn(Object *obj)
     CPUX86State *env = &cpu->env;
     FeatureWord w;
 
+    env->nr_dies = 1;
     cpu_set_cpustate_pointers(cpu);
 
     object_property_add(obj, "family", "int",

target/i386/cpu.h

@@ -1385,6 +1385,8 @@ typedef struct CPUX86State {
     uint64_t xss;
 
     TPRAccess tpr_access_type;
+
+    unsigned nr_dies;
 } CPUX86State;
 
 struct kvm_msrs;