[PATCH v10 1/9] s390x/cpu topology: core_id sets s390x CPU topology

[Pierre Morel]

In the S390x CPU topology the core_id specifies the CPU address
and the position of the core withing the topology.

Let's build the topology based on the core_id.
s390x/cpu topology: core_id sets s390x CPU topology

In the S390x CPU topology the core_id specifies the CPU address
and the position of the cpu withing the topology.

Let's build the topology based on the core_id.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
---
 include/hw/s390x/cpu-topology.h |  45 +++++++++++
 hw/s390x/cpu-topology.c         | 132 ++++++++++++++++++++++++++++++++
 hw/s390x/s390-virtio-ccw.c      |  21 +++++
 hw/s390x/meson.build            |   1 +
 4 files changed, 199 insertions(+)
 create mode 100644 include/hw/s390x/cpu-topology.h
 create mode 100644 hw/s390x/cpu-topology.c

diff --git a/include/hw/s390x/cpu-topology.h b/include/hw/s390x/cpu-topology.h
new file mode 100644
index 0000000000..66c171d0bc
--- /dev/null
+++ b/include/hw/s390x/cpu-topology.h
@@ -0,0 +1,45 @@
+/*
+ * CPU Topology
+ *
+ * Copyright 2022 IBM Corp.
+ *
+ * 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.
+ */
+#ifndef HW_S390X_CPU_TOPOLOGY_H
+#define HW_S390X_CPU_TOPOLOGY_H
+
+#include "hw/qdev-core.h"
+#include "qom/object.h"
+
+typedef struct S390TopoContainer {
+    int active_count;
+} S390TopoContainer;
+
+#define S390_TOPOLOGY_CPU_IFL 0x03
+#define S390_TOPOLOGY_MAX_ORIGIN ((63 + S390_MAX_CPUS) / 64)
+typedef struct S390TopoTLE {
+    uint64_t mask[S390_TOPOLOGY_MAX_ORIGIN];
+} S390TopoTLE;
+
+struct S390Topology {
+    SysBusDevice parent_obj;
+    int cpus;
+    S390TopoContainer *socket;
+    S390TopoTLE *tle;
+    MachineState *ms;
+};
+
+#define TYPE_S390_CPU_TOPOLOGY "s390-topology"
+OBJECT_DECLARE_SIMPLE_TYPE(S390Topology, S390_CPU_TOPOLOGY)
+
+S390Topology *s390_get_topology(void);
+void s390_topology_new_cpu(int core_id);
+
+static inline bool s390_has_topology(void)
+{
+    return false;
+}
+
+#endif
diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c
new file mode 100644
index 0000000000..42b22a1831
--- /dev/null
+++ b/hw/s390x/cpu-topology.c
@@ -0,0 +1,132 @@
+/*
+ * CPU Topology
+ *
+ * Copyright IBM Corp. 2022
+ * Author(s): Pierre Morel <pmorel@linux.ibm.com>
+
+ * 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/sysbus.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"
+
+S390Topology *s390_get_topology(void)
+{
+    static S390Topology *s390Topology;
+
+    if (!s390Topology) {
+        s390Topology = S390_CPU_TOPOLOGY(
+            object_resolve_path(TYPE_S390_CPU_TOPOLOGY, NULL));
+    }
+
+    return s390Topology;
+}
+
+/*
+ * s390_topology_new_cpu:
+ * @core_id: the core ID is machine wide
+ *
+ * The topology returned by s390_get_topology(), gives us the CPU
+ * topology established by the -smp QEMU aruments.
+ * The core-id gives:
+ *  - the Container TLE (Topology List Entry) containing the CPU TLE.
+ *  - in the CPU TLE the origin, or offset of the first bit in the core mask
+ *  - the bit in the CPU TLE core mask
+ */
+void s390_topology_new_cpu(int core_id)
+{
+    S390Topology *topo = s390_get_topology();
+    int socket_id;
+    int bit, origin;
+
+    /* In the case no Topology is used nothing is to be done here */
+    if (!topo) {
+        return;
+    }
+
+    socket_id = core_id / topo->cpus;
+
+    /*
+     * At the core level, each CPU is represented by a bit in a 64bit
+     * unsigned long which represent the presence of a CPU.
+     * The firmware assume that all CPU in a CPU TLE have the same
+     * type, polarization and are all dedicated or shared.
+     * In that case the origin variable represents the offset of the first
+     * CPU in the CPU container.
+     * More than 64 CPUs per socket are represented in several CPU containers
+     * inside the socket container.
+     * The only reason to have several S390TopologyCores inside a socket is
+     * to have more than 64 CPUs.
+     * In that case the origin variable represents the offset of the first CPU
+     * in the CPU container. More than 64 CPUs per socket are represented in
+     * several CPU containers inside the socket container.
+     */
+    bit = core_id;
+    origin = bit / 64;
+    bit %= 64;
+    bit = 63 - bit;
+
+    topo->socket[socket_id].active_count++;
+    set_bit(bit, &topo->tle[socket_id].mask[origin]);
+}
+
+/**
+ * s390_topology_realize:
+ * @dev: the device state
+ * @errp: the error pointer (not used)
+ *
+ * During realize the machine CPU topology is initialized with the
+ * QEMU -smp parameters.
+ * The maximum count of CPU TLE in the all Topology can not be greater
+ * than the maximum CPUs.
+ */
+static void s390_topology_realize(DeviceState *dev, Error **errp)
+{
+    MachineState *ms = MACHINE(qdev_get_machine());
+    S390Topology *topo = S390_CPU_TOPOLOGY(dev);
+
+    topo->cpus = ms->smp.cores * ms->smp.threads;
+
+    topo->socket = g_new0(S390TopoContainer, ms->smp.sockets);
+    topo->tle = g_new0(S390TopoTLE, ms->smp.max_cpus);
+
+    topo->ms = ms;
+}
+
+/**
+ * topology_class_init:
+ * @oc: Object class
+ * @data: (not used)
+ *
+ * A very simple object we will need for reset and migration.
+ */
+static void topology_class_init(ObjectClass *oc, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(oc);
+
+    dc->realize = s390_topology_realize;
+    set_bit(DEVICE_CATEGORY_MISC, dc->categories);
+}
+
+static const TypeInfo cpu_topology_info = {
+    .name          = TYPE_S390_CPU_TOPOLOGY,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(S390Topology),
+    .class_init    = topology_class_init,
+};
+
+static void topology_register(void)
+{
+    type_register_static(&cpu_topology_info);
+}
+type_init(topology_register);
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 03855c7231..aa99a62e42 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -43,6 +43,7 @@
 #include "sysemu/sysemu.h"
 #include "hw/s390x/pv.h"
 #include "migration/blocker.h"
+#include "hw/s390x/cpu-topology.h"
 
 static Error *pv_mig_blocker;
 
@@ -94,6 +95,18 @@ static void s390_init_cpus(MachineState *machine)
     }
 }
 
+static void s390_init_topology(MachineState *machine)
+{
+    DeviceState *dev;
+
+    if (s390_has_topology()) {
+        dev = qdev_new(TYPE_S390_CPU_TOPOLOGY);
+        object_property_add_child(&machine->parent_obj,
+                                  TYPE_S390_CPU_TOPOLOGY, OBJECT(dev));
+        sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
+    }
+}
+
 static const char *const reset_dev_types[] = {
     TYPE_VIRTUAL_CSS_BRIDGE,
     "s390-sclp-event-facility",
@@ -244,6 +257,9 @@ static void ccw_init(MachineState *machine)
     /* init memory + setup max page size. Required for the CPU model */
     s390_memory_init(machine->ram);
 
+    /* Adding the topology must be done before CPU intialization */
+    s390_init_topology(machine);
+
     /* init CPUs (incl. CPU model) early so s390_has_feature() works */
     s390_init_cpus(machine);
 
@@ -306,6 +322,11 @@ static void s390_cpu_plug(HotplugHandler *hotplug_dev,
     g_assert(!ms->possible_cpus->cpus[cpu->env.core_id].cpu);
     ms->possible_cpus->cpus[cpu->env.core_id].cpu = OBJECT(dev);
 
+    /* Inserting the CPU in the Topology can not fail */
+    if (s390_has_topology()) {
+        s390_topology_new_cpu(cpu->env.core_id);
+    }
+
     if (dev->hotplugged) {
         raise_irq_cpu_hotplug();
     }
diff --git a/hw/s390x/meson.build b/hw/s390x/meson.build
index f291016fee..653f6ab488 100644
--- a/hw/s390x/meson.build
+++ b/hw/s390x/meson.build
@@ -2,6 +2,7 @@ s390x_ss = ss.source_set()
 s390x_ss.add(files(
   'ap-bridge.c',
   'ap-device.c',
+  'cpu-topology.c',
   'ccw-device.c',
   'css-bridge.c',
   'css.c',
-- 
2.31.1