[PATCH v9 09/10] s390x/cpu_topology: activating CPU topology

[Pierre Morel <pmorel@linux.ibm.com>]

Starting with a new machine, s390-virtio-ccw-7.2, the machine
property topology-disable is set to false while it is kept to
true for older machine.
This allows migrating older machine without disabling the ctop
CPU feature for older machine, thus keeping existing start scripts.

The KVM capability, KVM_CAP_S390_CPU_TOPOLOGY is used to
activate the S390_FEAT_CONFIGURATION_TOPOLOGY feature and
the topology facility for the guest in the case the topology
is not disabled.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
---
 hw/core/machine.c                  |  5 +++
 hw/s390x/s390-virtio-ccw.c         | 55 ++++++++++++++++++++++++++----
 include/hw/boards.h                |  3 ++
 include/hw/s390x/s390-virtio-ccw.h |  1 +
 target/s390x/kvm/kvm.c             | 14 ++++++++
 5 files changed, 72 insertions(+), 6 deletions(-)

diff --git a/hw/core/machine.c b/hw/core/machine.c
index 4c5c8d1655..cbcdd40763 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -40,6 +40,11 @@
 #include "hw/virtio/virtio-pci.h"
 #include "qom/object_interfaces.h"
 
+GlobalProperty hw_compat_7_1[] = {
+    { "s390x-cpu", "ctop", "off"},
+};
+const size_t hw_compat_7_1_len = G_N_ELEMENTS(hw_compat_7_1);
+
 GlobalProperty hw_compat_7_0[] = {
     { "arm-gicv3-common", "force-8-bit-prio", "on" },
     { "nvme-ns", "eui64-default", "on"},
diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 1fa98740de..3078e68df7 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -249,11 +249,16 @@ 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*/
-    dev = qdev_new(TYPE_S390_CPU_TOPOLOGY);
-    object_property_add_child(qdev_get_machine(), TYPE_S390_CPU_TOPOLOGY,
-                              OBJECT(dev));
-    sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
+    /*
+     * Adding the topology must be done before CPU intialization but
+     * only in the case it is not disabled for migration purpose.
+     */
+    if (!S390_CCW_MACHINE(machine)->topology_disable) {
+        dev = qdev_new(TYPE_S390_CPU_TOPOLOGY);
+        object_property_add_child(qdev_get_machine(), TYPE_S390_CPU_TOPOLOGY,
+                                  OBJECT(dev));
+        sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
+    }
 
     /* init CPUs (incl. CPU model) early so s390_has_feature() works */
     s390_init_cpus(machine);
@@ -676,6 +681,21 @@ static inline void machine_set_zpcii_disable(Object *obj, bool value,
     ms->zpcii_disable = value;
 }
 
+static inline bool machine_get_topology_disable(Object *obj, Error **errp)
+{
+    S390CcwMachineState *ms = S390_CCW_MACHINE(obj);
+
+    return ms->topology_disable;
+}
+
+static inline void machine_set_topology_disable(Object *obj, bool value,
+                                                Error **errp)
+{
+    S390CcwMachineState *ms = S390_CCW_MACHINE(obj);
+
+    ms->topology_disable = value;
+}
+
 static S390CcwMachineClass *current_mc;
 
 /*
@@ -778,6 +798,13 @@ static inline void s390_machine_initfn(Object *obj)
     object_property_set_description(obj, "zpcii-disable",
             "disable zPCI interpretation facilties");
     object_property_set_bool(obj, "zpcii-disable", false, NULL);
+
+    object_property_add_bool(obj, "topology-disable",
+                             machine_get_topology_disable,
+                             machine_set_topology_disable);
+    object_property_set_description(obj, "topology-disable",
+            "disable zPCI interpretation facilties");
+    object_property_set_bool(obj, "topology-disable", false, NULL);
 }
 
 static const TypeInfo ccw_machine_info = {
@@ -830,14 +857,29 @@ bool css_migration_enabled(void)
     }                                                                         \
     type_init(ccw_machine_register_##suffix)
 
+static void ccw_machine_7_2_instance_options(MachineState *machine)
+{
+}
+
+static void ccw_machine_7_2_class_options(MachineClass *mc)
+{
+}
+DEFINE_CCW_MACHINE(7_2, "7.2", true);
+
 static void ccw_machine_7_1_instance_options(MachineState *machine)
 {
+    S390CcwMachineState *ms = S390_CCW_MACHINE(machine);
+
+    ccw_machine_7_2_instance_options(machine);
+    ms->topology_disable = true;
 }
 
 static void ccw_machine_7_1_class_options(MachineClass *mc)
 {
+    ccw_machine_7_2_class_options(mc);
+    compat_props_add(mc->compat_props, hw_compat_7_1, hw_compat_7_1_len);
 }
-DEFINE_CCW_MACHINE(7_1, "7.1", true);
+DEFINE_CCW_MACHINE(7_1, "7.1", false);
 
 static void ccw_machine_7_0_instance_options(MachineState *machine)
 {
@@ -847,6 +889,7 @@ static void ccw_machine_7_0_instance_options(MachineState *machine)
     ccw_machine_7_1_instance_options(machine);
     s390_set_qemu_cpu_model(0x8561, 15, 1, qemu_cpu_feat);
     ms->zpcii_disable = true;
+
 }
 
 static void ccw_machine_7_0_class_options(MachineClass *mc)
diff --git a/include/hw/boards.h b/include/hw/boards.h
index 69e20c1252..6e9803aa2d 100644
--- a/include/hw/boards.h
+++ b/include/hw/boards.h
@@ -387,6 +387,9 @@ struct MachineState {
     } \
     type_init(machine_initfn##_register_types)
 
+extern GlobalProperty hw_compat_7_1[];
+extern const size_t hw_compat_7_1_len;
+
 extern GlobalProperty hw_compat_7_0[];
 extern const size_t hw_compat_7_0_len;
 
diff --git a/include/hw/s390x/s390-virtio-ccw.h b/include/hw/s390x/s390-virtio-ccw.h
index 9e7a0d75bc..b14660eecb 100644
--- a/include/hw/s390x/s390-virtio-ccw.h
+++ b/include/hw/s390x/s390-virtio-ccw.h
@@ -28,6 +28,7 @@ struct S390CcwMachineState {
     bool dea_key_wrap;
     bool pv;
     bool zpcii_disable;
+    bool topology_disable;
     uint8_t loadparm[8];
 };
 
diff --git a/target/s390x/kvm/kvm.c b/target/s390x/kvm/kvm.c
index cb14bcc012..6b7efee511 100644
--- a/target/s390x/kvm/kvm.c
+++ b/target/s390x/kvm/kvm.c
@@ -2385,6 +2385,7 @@ bool kvm_s390_cpu_models_supported(void)
 
 void kvm_s390_get_host_cpu_model(S390CPUModel *model, Error **errp)
 {
+    S390CcwMachineState *ms = S390_CCW_MACHINE(qdev_get_machine());
     struct kvm_s390_vm_cpu_machine prop = {};
     struct kvm_device_attr attr = {
         .group = KVM_S390_VM_CPU_MODEL,
@@ -2466,6 +2467,19 @@ void kvm_s390_get_host_cpu_model(S390CPUModel *model, Error **errp)
         set_bit(S390_FEAT_UNPACK, model->features);
     }
 
+    /*
+     * If we have the CPU Topology implemented in KVM activate
+     * the CPU TOPOLOGY feature.
+     */
+    if ((!ms->topology_disable) &&
+        kvm_check_extension(kvm_state, KVM_CAP_S390_CPU_TOPOLOGY)) {
+        if (kvm_vm_enable_cap(kvm_state, KVM_CAP_S390_CPU_TOPOLOGY, 0) < 0) {
+            error_setg(errp, "KVM: Error enabling KVM_CAP_S390_CPU_TOPOLOGY");
+            return;
+        }
+        set_bit(S390_FEAT_CONFIGURATION_TOPOLOGY, model->features);
+    }
+
     /* We emulate a zPCI bus and AEN, therefore we don't need HW support */
     set_bit(S390_FEAT_ZPCI, model->features);
     set_bit(S390_FEAT_ADAPTER_EVENT_NOTIFICATION, model->features);
-- 
2.31.1