Hello Pierre,
On 11/3/22 18:01, Pierre Morel wrote:
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.
Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
---
include/hw/s390x/cpu-topology.h | 41 ++++++++++
include/hw/s390x/s390-virtio-ccw.h | 1 +
target/s390x/cpu.h | 2 +
hw/s390x/cpu-topology.c | 125 +++++++++++++++++++++++++++++
hw/s390x/s390-virtio-ccw.c | 23 ++++++
hw/s390x/meson.build | 1 +
6 files changed, 193 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..4e16a2153d
--- /dev/null
+++ b/include/hw/s390x/cpu-topology.h
@@ -0,0 +1,41 @@
+/*
+ * CPU Topology
+ *
+ * Copyright IBM Corp. 2022
+ *
+ * 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"
+
+#define S390_TOPOLOGY_CPU_IFL 0x03
+#define S390_TOPOLOGY_MAX_ORIGIN ((63 + S390_MAX_CPUS) / 64)
+
+typedef struct S390TopoSocket {
+ int active_count;
+ uint64_t mask[S390_TOPOLOGY_MAX_ORIGIN];
+} S390TopoSocket;
+
+struct S390Topology {
+ SysBusDevice parent_obj;
+ uint32_t nr_cpus;
+ uint32_t nr_sockets;
+ S390TopoSocket *socket;
+};
+
+#define TYPE_S390_CPU_TOPOLOGY "s390-topology"
+OBJECT_DECLARE_SIMPLE_TYPE(S390Topology, S390_CPU_TOPOLOGY)
+
+void s390_topology_new_cpu(S390CPU *cpu);
+
+static inline bool s390_has_topology(void)
+{
+ return false;
+}
+
+#endif
diff --git a/include/hw/s390x/s390-virtio-ccw.h b/include/hw/s390x/s390-virtio-ccw.h
index 4f8a39abda..23b472708d 100644
--- a/include/hw/s390x/s390-virtio-ccw.h
+++ b/include/hw/s390x/s390-virtio-ccw.h
@@ -29,6 +29,7 @@ struct S390CcwMachineState {
bool pv;
bool zpcii_disable;
uint8_t loadparm[8];
+ void *topology;
I think it is safe to use 'DeviceState *' or 'Object *' for the pointer
under machine. What is most practical.
};
struct S390CcwMachineClass {
diff --git a/target/s390x/cpu.h b/target/s390x/cpu.h
index 7d6d01325b..c9066b2496 100644
--- a/target/s390x/cpu.h
+++ b/target/s390x/cpu.h
@@ -175,6 +175,8 @@ struct ArchCPU {
/* needed for live migration */
void *irqstate;
uint32_t irqstate_saved_size;
+ /* Topology this CPU belongs too */
+ void *topology;
However, under the CPU, we don't know what the future changes reserve
for us and I would call the attribute 'opaque' or 'machine_data'.
For now, it only holds a reference to the S390Topology device model
but it could become a struct with time.
};
diff --git a/hw/s390x/cpu-topology.c b/hw/s390x/cpu-topology.c
new file mode 100644
index 0000000000..6af41d3d7b
--- /dev/null
+++ b/hw/s390x/cpu-topology.c
@@ -0,0 +1,125 @@
+/*
+ * 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/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"
+
+/*
+ * s390_topology_new_cpu:
+ * @cpu: a pointer to the new CPU
+ *
+ * The topology pointed by S390CPU, gives us the CPU topology
+ * established by the -smp QEMU aruments.
+ * The core-id is used to calculate the position of the CPU inside
+ * the topology:
+ * - the socket, container TLE, containing the CPU, we have one socket
+ * for every nr_cpus (nr_cpus = smp.cores * smp.threads)
+ * - the CPU TLE inside the socket, we have potentionly up to 4 CPU TLE
+ * in a container TLE with the assumption that all CPU are identical
+ * with the same polarity and entitlement because we have maximum 256
+ * CPUs and each TLE can hold up to 64 identical CPUs.
+ * - the bit in the 64 bit CPU TLE core mask
+ */
+void s390_topology_new_cpu(S390CPU *cpu)
+{
+ S390Topology *topo = (S390Topology *)cpu->topology;
where is cpu->topology set ?
+ int core_id = cpu->env.core_id;
+ int bit, origin;
+ int socket_id;
+
+ socket_id = core_id / topo->nr_cpus;
+
+ /*
+ * At the core level, each CPU is represented by a bit in a 64bit
+ * uint64_t 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->socket[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());
hmm,
+ S390Topology *topo = S390_CPU_TOPOLOGY(dev);
+
+ topo->nr_cpus = ms->smp.cores * ms->smp.threads;
+ topo->nr_sockets = ms->smp.sockets;
These properties should be set in s390_init_topology() with :
object_property_set_int(OBJECT(dev), "num-cpus",
ms->smp.cores * ms->smp.threads, errp);
object_property_set_int(OBJECT(dev), "num-sockets",
ms->smp.sockets, errp);
before calling sysbus_realize_and_unref()
+ topo->socket = g_new0(S390TopoSocket, topo->nr_sockets);
For consistency, you could add an unrealize handler to free the array.
+}
+
+static Property s390_topology_properties[] = {
+ DEFINE_PROP_UINT32("nr_cpus", S390Topology, nr_cpus, 1),
+ DEFINE_PROP_UINT32("nr_sockets", S390Topology, nr_sockets, 1),
A quick audit of the property names in QEMU code shows that a "num-" prefix
is usually preferred.
+ DEFINE_PROP_END_OF_LIST(),
+};
+
+/**
+ * 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;
+ device_class_set_props(dc, s390_topology_properties);
+ 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 9ab91df5b1..5776d3e58f 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -44,6 +44,7 @@
#include "hw/s390x/pv.h"
#include "migration/blocker.h"
#include "qapi/visitor.h"
+#include "hw/s390x/cpu-topology.h"
static Error *pv_mig_blocker;
@@ -102,6 +103,19 @@ static void s390_init_cpus(MachineState *machine)
}
}
+static void s390_init_topology(MachineState *machine)
+{
+ DeviceState *dev;
+
+ if (s390_has_topology()) {
I would move the s390_has_topology() check in the caller.
+ 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);
+ S390_CCW_MACHINE(machine)->topology = dev;
and I would move the assignment in the caller also.
+ }
+}
+
static const char *const reset_dev_types[] = {
TYPE_VIRTUAL_CSS_BRIDGE,
"s390-sclp-event-facility",
@@ -252,6 +266,9 @@ 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 initialization */
+ s390_init_topology(machine);
+
/* init CPUs (incl. CPU model) early so s390_has_feature() works */
s390_init_cpus(machine);
@@ -314,6 +331,12 @@ 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_CCW_MACHINE(ms)->topology) {
+ cpu->topology = S390_CCW_MACHINE(ms)->topology;
Two QOM cast. One should be enough. Please introduce a local variable.
+ s390_topology_new_cpu(cpu);
I would pass the 'topology' object as a parameter of s390_topology_new_cpu()
and do the cpu->topology assignment in the same routine.
May be rename it also to :
void s390_topology_add_cpu(S390Topology *topo, S390CPU *cpu)
Thanks,
C.
+ }
+
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',
