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Diffstat (limited to 'include/hw/cpu/cluster.h')
| -rw-r--r-- | include/hw/cpu/cluster.h | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/include/hw/cpu/cluster.h b/include/hw/cpu/cluster.h index 7381823243..549c2d31d4 100644 --- a/include/hw/cpu/cluster.h +++ b/include/hw/cpu/cluster.h @@ -34,12 +34,36 @@ * 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" #define CPU_CLUSTER(obj) \ OBJECT_CHECK(CPUClusterState, (obj), TYPE_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 |