Hello Pierre,
On 10/12/22 18:20, 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.
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.
The commit log is doubled.
Signed-off-by: Pierre Morel <pmorel@xxxxxxxxxxxxx>
---
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;
This structure does not seem very useful.
+
+#define S390_TOPOLOGY_CPU_IFL 0x03
+#define S390_TOPOLOGY_MAX_ORIGIN ((63 + S390_MAX_CPUS) / 64)
+typedef struct S390TopoTLE {
The 'Topo' is redundant as TLE stands for 'topology-list entry'. This is minor.
+ uint64_t mask[S390_TOPOLOGY_MAX_ORIGIN];
+} S390TopoTLE;
+
+struct S390Topology {
+ SysBusDevice parent_obj;
+ int cpus;
+ S390TopoContainer *socket;
+ S390TopoTLE *tle;
+ MachineState *ms;
hmm, it would be cleaner to introduce the fields and properties needed
by the S390Topology model and avoid dragging the machine object pointer.
AFAICT, these properties would be :
"nr-cpus"
"max-cpus"
"nr-sockets"
+};
+
+#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
The Copyright tag is different in the .h file.
+ * 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"
+
+S390Topology *s390_get_topology(void)
+{
+ static S390Topology *s390Topology;
+
+ if (!s390Topology) {
+ s390Topology = S390_CPU_TOPOLOGY(
+ object_resolve_path(TYPE_S390_CPU_TOPOLOGY, NULL));
+ }
+
+ return s390Topology;
I am not convinced this routine is useful. The s390Topology pointer
could be stored under the machine state I think. It wouldn't be a
problem when CPUs are hot plugged since we have access to the machine
in the hot plug handler.
For the stsi call, 'struct ArchCPU' probably lacks a back pointer to
the machine objects with which CPU interact. These are typically
interrupt controllers or this new s390Topology model. You could add
the pointer there or, better, under a generic 'void *opaque' attribute.
That said, what you did works fine. The modeling could be cleaner.
+}
+
+/*
+ * 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;
+ }
I would move this test in the caller.
+
+ 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]);
here, the tle array is indexed with a socket id and ...
+}
+
+/**
+ * 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);
... here, the tle array is allocated with max_cpus and this looks
weird. I will dig the specs to try to understand.
+
+ topo->ms = ms;
See comment above regarding the properties.
+}
+
+/**
+ * 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 */
initialization
+ 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',
