On 08/12/2022 10.44, Pierre Morel wrote:
We will need a Topology device to transfer the topology
during migration and to implement machine reset.
The device creation is fenced by s390_has_topology().
Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
---
[...]
diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c
new file mode 100644
index 0000000000..b3e59873f6
--- /dev/null
+++ b/hw/s390x/cpu-topology.c
@@ -0,0 +1,149 @@
+/*
+ * CPU Topology
+ *
+ * Copyright IBM Corp. 2022
+ * Author(s): Pierre Morel <pmorel@xxxxxxxxxxxxx>
+
+ * This work is licensed under the terms of the GNU GPL, version 2 or (at
+ * your option) any later version. See the COPYING file in the top-level
+ * directory.
+ */
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qemu/error-report.h"
+#include "hw/qdev-properties.h"
+#include "hw/boards.h"
+#include "qemu/typedefs.h"
+#include "target/s390x/cpu.h"
+#include "hw/s390x/s390-virtio-ccw.h"
+#include "hw/s390x/cpu-topology.h"
+
+/**
+ * s390_has_topology
+ *
+ * Return false until the commit activating the topology is
+ * commited.
+ */
+bool s390_has_topology(void)
+{
+ return false;
+}
+
+/**
+ * s390_get_topology
+ *
+ * Returns a pointer to the topology.
+ *
+ * This function is called when we know the topology exist.
+ * Testing if the topology exist is done with s390_has_topology()
+ */
+S390Topology *s390_get_topology(void)
+{
+ static S390Topology *s390Topology;
+
+ if (!s390Topology) {
+ s390Topology = S390_CPU_TOPOLOGY(
+ object_resolve_path(TYPE_S390_CPU_TOPOLOGY, NULL));
+ }
+
+ assert(s390Topology);
I think you can move the assert() into the body of the if-statement.
+ return s390Topology;
+}
+
+/**
+ * s390_init_topology
+ * @machine: The Machine state, used to retrieve the SMP parameters
+ * @errp: the error pointer in case of problem
+ *
+ * This function creates and initialize the S390Topology with
+ * the QEMU -smp parameters we will use during adding cores to the
+ * topology.
+ */
+void s390_init_topology(MachineState *machine, Error **errp)
+{
+ DeviceState *dev;
+
+ if (machine->smp.threads > 1) {
+ error_setg(errp, "CPU Topology do not support multithreading");
s/CPU Toplogy do/CPU topology does/
+ return;
+ }
+
+ dev = qdev_new(TYPE_S390_CPU_TOPOLOGY);
+
+ object_property_add_child(&machine->parent_obj,
+ TYPE_S390_CPU_TOPOLOGY, OBJECT(dev));
+ object_property_set_int(OBJECT(dev), "num-cores",
+ machine->smp.cores, errp);
+ object_property_set_int(OBJECT(dev), "num-sockets",
+ machine->smp.sockets, errp);
+
+ sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), errp);
+}
Thomas
