[Qemu-devel] [PATCH v6 7/7] s390x/cpu: Allow hotplug of CPUs

[Matthew Rosato <mjrosato@linux.vnet.ibm.com>]

Implement cpu hotplug routine and add the machine hook.

Signed-off-by: Matthew Rosato <mjrosato@linux.vnet.ibm.com>
---
 hw/s390x/s390-virtio-ccw.c | 33 +++++++++++++++++++++++++++++++++
 target-s390x/cpu.c         |  7 +++++++
 2 files changed, 40 insertions(+)

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 3090e76..ea007e8 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -22,6 +22,7 @@
 #include "s390-pci-bus.h"
 #include "hw/s390x/storage-keys.h"
 #include "hw/compat.h"
+#include "qom/cpu.h"
 
 #define TYPE_S390_CCW_MACHINE               "s390-ccw-machine"
 
@@ -185,6 +186,37 @@ static HotplugHandler *s390_get_hotplug_handler(MachineState *machine,
     return NULL;
 }
 
+static void s390_hot_add_cpu(const int64_t id, Error **errp)
+{
+    MachineState *machine = MACHINE(qdev_get_machine());
+
+    if (id < 0) {
+        error_setg(errp, "Invalid CPU id: %" PRIi64, id);
+        return;
+    }
+
+    if (cpu_exists(id)) {
+        error_setg(errp, "Unable to add CPU: %" PRIi64
+                   ", it already exists", id);
+        return;
+    }
+
+    if (id >= max_cpus) {
+        error_setg(errp, "Unable to add CPU: %" PRIi64
+                   ", max allowed: %d", id, max_cpus - 1);
+        return;
+    }
+
+    if (id != (last_cpu->cpu_index + 1)) {
+        error_setg(errp, "Unable to add CPU: %" PRIi64
+                   ", The next available id is %d", id,
+                   (last_cpu->cpu_index + 1));
+        return;
+    }
+
+    cpu_s390x_init(machine->cpu_model);
+}
+
 static void ccw_machine_class_init(ObjectClass *oc, void *data)
 {
     MachineClass *mc = MACHINE_CLASS(oc);
@@ -193,6 +225,7 @@ static void ccw_machine_class_init(ObjectClass *oc, void *data)
 
     mc->init = ccw_init;
     mc->reset = s390_machine_reset;
+    mc->hot_add_cpu = s390_hot_add_cpu;
     mc->block_default_type = IF_VIRTIO;
     mc->no_cdrom = 1;
     mc->no_floppy = 1;
diff --git a/target-s390x/cpu.c b/target-s390x/cpu.c
index 8dfd063..1a4977e 100644
--- a/target-s390x/cpu.c
+++ b/target-s390x/cpu.c
@@ -32,6 +32,7 @@
 #include "trace.h"
 #ifndef CONFIG_USER_ONLY
 #include "sysemu/arch_init.h"
+#include "hw/s390x/sclp.h"
 #endif
 
 #define CR0_RESET       0xE0UL
@@ -211,6 +212,12 @@ static void s390_cpu_realizefn(DeviceState *dev, Error **errp)
 #endif
 
     scc->parent_realize(dev, errp);
+
+#if !defined(CONFIG_USER_ONLY)
+    if (dev->hotplugged) {
+        raise_irq_cpu_hotplug();
+    }
+#endif
 }
 
 static void s390_cpu_initfn(Object *obj)
-- 
1.9.1