qemu

FORK: QEMU emulator
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cluster.h (3026B)

      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"
     58 OBJECT_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  */
     73 struct CPUClusterState {
     74     /*< private >*/
     75     DeviceState parent_obj;
     76 
     77     /*< public >*/
     78     uint32_t cluster_id;
     79 };
     80 
     81 #endif