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
  25 /*
  26  * CPU Cluster type
  27  *
  28  * A cluster is a group of CPUs which are all identical and have the same view
  29  * of the rest of the system. It is mainly an internal QEMU representation and
  30  * does not necessarily match with the notion of clusters on the real hardware.
  31  *
  32  * If CPUs are not identical (for example, Cortex-A53 and Cortex-A57 CPUs in an
  33  * Arm big.LITTLE system) they should be in different clusters. If the CPUs do
  34  * not have the same view of memory (for example the main CPU and a management
  35  * controller processor) they should be in different clusters.
  36  *
  37  * A cluster is created by creating an object of TYPE_CPU_CLUSTER, and then
  38  * adding the CPUs to it as QOM child objects (e.g. using the
  39  * object_initialize_child() or object_property_add_child() functions).
  40  * The CPUs may be either direct children of the cluster object, or indirect
  41  * children (e.g. children of children of the cluster object).
  42  *
  43  * All CPUs must be added as children before the cluster is realized.
  44  * (Regrettably QOM provides no way to prevent adding children to a realized
  45  * object and no way for the parent to be notified when a new child is added
  46  * to it, so this restriction is not checked for, but the system will not
  47  * behave correctly if it is not adhered to. The cluster will assert that
  48  * it contains at least one CPU, which should catch most inadvertent
  49  * violations of this constraint.)
  50  *
  51  * A CPU which is not put into any cluster will be considered implicitly
  52  * to be in a cluster with all the other "loose" CPUs, so all CPUs that are
  53  * not assigned to clusters must be identical.
  54  */
  55
  56 #define TYPE_CPU_CLUSTER "cpu-cluster"
  57 #define CPU_CLUSTER(obj) \
  58     OBJECT_CHECK(CPUClusterState, (obj), TYPE_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  */
  73 typedef struct CPUClusterState {
  74     /*< private >*/
  75     DeviceState parent_obj;
  76
  77     /*< public >*/
  78     uint32_t cluster_id;
  79 } CPUClusterState;
  80
  81 #endif