From: Zhao Liu <zhao1.liu@intel.com>

Abstract the root of topology tree as a special topology device
"cpu-slot".

Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
---
 MAINTAINERS                |  2 ++
 hw/core/cpu-slot.c         | 48 ++++++++++++++++++++++++++++++++++++++
 hw/core/meson.build        |  1 +
 include/hw/core/cpu-slot.h | 38 ++++++++++++++++++++++++++++++
 4 files changed, 89 insertions(+)
 create mode 100644 hw/core/cpu-slot.c
 create mode 100644 include/hw/core/cpu-slot.h

diff --git a/MAINTAINERS b/MAINTAINERS
index 4b373ff46ce3..ac08b5a8c4e0 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1856,6 +1856,7 @@ R: Philippe Mathieu-Daudé <philmd@linaro.org>
 R: Yanan Wang <wangyanan55@huawei.com>
 S: Supported
 F: hw/core/cpu.c
+F: hw/core/cpu-slot.c
 F: hw/core/cpu-topo.c
 F: hw/core/machine-qmp-cmds.c
 F: hw/core/machine.c
@@ -1872,6 +1873,7 @@ F: qapi/machine-common.json
 F: qapi/machine-target.json
 F: include/hw/boards.h
 F: include/hw/core/cpu.h
+F: include/hw/core/cpu-slot.h
 F: include/hw/core/cpu-topo.h
 F: include/hw/cpu/book.h
 F: include/hw/cpu/cluster.h
diff --git a/hw/core/cpu-slot.c b/hw/core/cpu-slot.c
new file mode 100644
index 000000000000..5aef5b0189c2
--- /dev/null
+++ b/hw/core/cpu-slot.c
@@ -0,0 +1,48 @@
+/*
+ * CPU slot device abstraction
+ *
+ * Copyright (c) 2023 Intel Corporation
+ * Author: Zhao Liu <zhao1.liu@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License,
+ * or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+
+#include "hw/core/cpu-slot.h"
+
+static void cpu_slot_class_init(ObjectClass *oc, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(oc);
+    CPUTopoClass *tc = CPU_TOPO_CLASS(oc);
+
+    set_bit(DEVICE_CATEGORY_CPU_DEF, dc->categories);
+    dc->user_creatable = false;
+
+    tc->level = CPU_TOPO_ROOT;
+}
+
+static const TypeInfo cpu_slot_type_info = {
+    .name = TYPE_CPU_SLOT,
+    .parent = TYPE_CPU_TOPO,
+    .class_init = cpu_slot_class_init,
+    .instance_size = sizeof(CPUSlot),
+};
+
+static void cpu_slot_register_types(void)
+{
+    type_register_static(&cpu_slot_type_info);
+}
+
+type_init(cpu_slot_register_types)
diff --git a/hw/core/meson.build b/hw/core/meson.build
index 501d2529697e..3347c054e162 100644
--- a/hw/core/meson.build
+++ b/hw/core/meson.build
@@ -23,6 +23,7 @@ else
 endif
 
 common_ss.add(files('cpu-common.c'))
+common_ss.add(files('cpu-slot.c'))
 common_ss.add(files('cpu-topo.c'))
 common_ss.add(files('machine-smp.c'))
 system_ss.add(when: 'CONFIG_FITLOADER', if_true: files('loader-fit.c'))
diff --git a/include/hw/core/cpu-slot.h b/include/hw/core/cpu-slot.h
new file mode 100644
index 000000000000..718c8ecaa751
--- /dev/null
+++ b/include/hw/core/cpu-slot.h
@@ -0,0 +1,38 @@
+/*
+ * CPU slot device abstraction
+ *
+ * Copyright (c) 2023 Intel Corporation
+ * Author: Zhao Liu <zhao1.liu@intel.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License,
+ * or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef CPU_SLOT_H
+#define CPU_SLOT_H
+
+#include "hw/core/cpu-topo.h"
+#include "hw/qdev-core.h"
+
+#define TYPE_CPU_SLOT "cpu-slot"
+
+OBJECT_DECLARE_SIMPLE_TYPE(CPUSlot, CPU_SLOT)
+
+struct CPUSlot {
+    /*< private >*/
+    CPUTopoState parent_obj;
+
+    /*< public >*/
+};
+
+#endif /* CPU_SLOT_H */
-- 
2.34.1