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diff --git a/include/hw/cpu/cluster.h b/include/hw/cpu/cluster.h
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+/*
+ * QEMU CPU cluster
+ *
+ * Copyright (c) 2018 GreenSocs SAS
+ *
+ * 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/gpl-2.0.html>
+ */
+#ifndef HW_CPU_CLUSTER_H
+#define HW_CPU_CLUSTER_H
+
+#include "hw/qdev-core.h"
+#include "qom/object.h"
+
+/*
+ * CPU Cluster type
+ *
+ * A cluster is a group of CPUs which are all identical and have the same view
+ * of the rest of the system. It is mainly an internal QEMU representation and
+ * does not necessarily match with the notion of clusters on the real hardware.
+ *
+ * If CPUs are not identical (for example, Cortex-A53 and Cortex-A57 CPUs in an
+ * Arm big.LITTLE system) they should be in different clusters. If the CPUs do
+ * not have the same view of memory (for example the main CPU and a management
+ * controller processor) they should be in different clusters.
+ *
+ * A cluster is created by creating an object of TYPE_CPU_CLUSTER, and then
+ * adding the CPUs to it as QOM child objects (e.g. using the
+ * object_initialize_child() or object_property_add_child() functions).
+ * The CPUs may be either direct children of the cluster object, or indirect
+ * children (e.g. children of children of the cluster object).
+ *
+ * All CPUs must be added as children before the cluster is realized.
+ * (Regrettably QOM provides no way to prevent adding children to a realized
+ * object and no way for the parent to be notified when a new child is added
+ * to it, so this restriction is not checked for, but the system will not
+ * behave correctly if it is not adhered to. The cluster will assert that
+ * it contains at least one CPU, which should catch most inadvertent
+ * violations of this constraint.)
+ *
+ * A CPU which is not put into any cluster will be considered implicitly
+ * to be in a cluster with all the other "loose" CPUs, so all CPUs that are
+ * not assigned to clusters must be identical.
+ */
+
+#define TYPE_CPU_CLUSTER "cpu-cluster"
+OBJECT_DECLARE_SIMPLE_TYPE(CPUClusterState, CPU_CLUSTER)
+
+/*
+ * This limit is imposed by TCG, which puts the cluster ID into an
+ * 8 bit field (and uses all-1s for the default "not in any cluster").
+ */
+#define MAX_CLUSTERS 255
+
+/**
+ * CPUClusterState:
+ * @cluster_id: The cluster ID. This value is for internal use only and should
+ *   not be exposed directly to the user or to the guest.
+ *
+ * State of a CPU cluster.
+ */
+struct CPUClusterState {
+    /*< private >*/
+    DeviceState parent_obj;
+
+    /*< public >*/
+    uint32_t cluster_id;
+};
+
+#endif