LXR qemu/include/hw/cpu/cluster.h

   1/*
   2 * QEMU CPU cluster
   3 *
   4 * Copyright (c) 2018 GreenSocs SAS
   5 *
   6 * This program is free software; you can redistribute it and/or
   7 * modify it under the terms of the GNU General Public License
   8 * as published by the Free Software Foundation; either version 2
   9 * of the License, or (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 *
  16 * You should have received a copy of the GNU General Public License
  17 * along with this program; if not, see
  18 * <http://www.gnu.org/licenses/gpl-2.0.html>
  19 */
  20#ifndef HW_CPU_CLUSTER_H
  21#define HW_CPU_CLUSTER_H
  22
  23#include "hw/qdev-core.h"
  24#include "qom/object.h"
  25
  26/*
  27 * CPU Cluster type
  28 *
  29 * A cluster is a group of CPUs which are all identical and have the same view
  30 * of the rest of the system. It is mainly an internal QEMU representation and
  31 * does not necessarily match with the notion of clusters on the real hardware.
  32 *
  33 * If CPUs are not identical (for example, Cortex-A53 and Cortex-A57 CPUs in an
  34 * Arm big.LITTLE system) they should be in different clusters. If the CPUs do
  35 * not have the same view of memory (for example the main CPU and a management
  36 * controller processor) they should be in different clusters.
  37 *
  38 * A cluster is created by creating an object of TYPE_CPU_CLUSTER, and then
  39 * adding the CPUs to it as QOM child objects (e.g. using the
  40 * object_initialize_child() or object_property_add_child() functions).
  41 * The CPUs may be either direct children of the cluster object, or indirect
  42 * children (e.g. children of children of the cluster object).
  43 *
  44 * All CPUs must be added as children before the cluster is realized.
  45 * (Regrettably QOM provides no way to prevent adding children to a realized
  46 * object and no way for the parent to be notified when a new child is added
  47 * to it, so this restriction is not checked for, but the system will not
  48 * behave correctly if it is not adhered to. The cluster will assert that
  49 * it contains at least one CPU, which should catch most inadvertent
  50 * violations of this constraint.)
  51 *
  52 * A CPU which is not put into any cluster will be considered implicitly
  53 * to be in a cluster with all the other "loose" CPUs, so all CPUs that are
  54 * not assigned to clusters must be identical.
  55 */
  56
  57#define TYPE_CPU_CLUSTER "cpu-cluster"
  58OBJECT_DECLARE_SIMPLE_TYPE(CPUClusterState, CPU_CLUSTER)
  59
  60/*
  61 * This limit is imposed by TCG, which puts the cluster ID into an
  62 * 8 bit field (and uses all-1s for the default "not in any cluster").
  63 */
  64#define MAX_CLUSTERS 255
  65
  66/**
  67 * CPUClusterState:
  68 * @cluster_id: The cluster ID. This value is for internal use only and should
  69 *   not be exposed directly to the user or to the guest.
  70 *
  71 * State of a CPU cluster.
  72 */
  73struct CPUClusterState {
  74    /*< private >*/
  75    DeviceState parent_obj;
  76
  77    /*< public >*/
  78    uint32_t cluster_id;
  79};
  80
  81#endif
  82