Revert "pc: Enforce adding CPUs contiguously and removing them in opposite order"

This reverts commit 4da7faae.

Since commit:
  pc: init CPUState->cpu_index with index in possible_cpus[]
cpu_index is stable regardless of the order cpus were created
and QEMU instance stays migratable always so limitation added
by 4da7faae could be safely removed.
Signed-off-by: NIgor Mammedov <imammedo@redhat.com>
Reviewed-by: NMichael S. Tsirkin <mst@redhat.com>
Signed-off-by: NEduardo Habkost <ehabkost@redhat.com>

hw/i386/pc.c

@@ -1818,23 +1818,6 @@ static void pc_cpu_unplug_request_cb(HotplugHandler *hotplug_dev,
         goto out;
     }
 
-    if (idx < pcms->possible_cpus->len - 1 &&
-        pcms->possible_cpus->cpus[idx + 1].cpu != NULL) {
-        X86CPU *cpu;
-
-        for (idx = pcms->possible_cpus->len - 1;
-             pcms->possible_cpus->cpus[idx].cpu == NULL; idx--) {
-            ;;
-        }
-
-        cpu = X86_CPU(pcms->possible_cpus->cpus[idx].cpu);
-        error_setg(&local_err, "CPU [socket-id: %u, core-id: %u,"
-                   " thread-id: %u] should be removed first",
-                   cpu->socket_id, cpu->core_id, cpu->thread_id);
-        goto out;
-
-    }
-
     hhc = HOTPLUG_HANDLER_GET_CLASS(pcms->acpi_dev);
     hhc->unplug_request(HOTPLUG_HANDLER(pcms->acpi_dev), dev, &local_err);
 
@@ -1932,23 +1915,6 @@ static void pc_cpu_pre_plug(HotplugHandler *hotplug_dev,
         return;
     }
 
-    if (idx != 0 && pcms->possible_cpus->cpus[idx - 1].cpu == NULL) {
-        PCMachineClass *pcmc = PC_MACHINE_GET_CLASS(pcms);
-
-        for (idx = 1; pcms->possible_cpus->cpus[idx].cpu != NULL; idx++) {
-            ;;
-        }
-
-        x86_topo_ids_from_apicid(pcms->possible_cpus->cpus[idx].arch_id,
-                                 smp_cores, smp_threads, &topo);
-
-        if (!pcmc->legacy_cpu_hotplug) {
-            error_setg(errp, "CPU [socket: %u, core: %u, thread: %u] should be"
-                       " added first", topo.pkg_id, topo.core_id, topo.smt_id);
-            return;
-        }
-    }
-
     /* if 'address' properties socket-id/core-id/thread-id are not set, set them
      * so that query_hotpluggable_cpus would show correct values
      */