[Qemu-devel] [PATCH v5 6/6] 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 |  1 +
 target-s390x/cpu.c         | 45 +++++++++++++++++++++++++++++++++++++++++++++
 target-s390x/cpu.h         |  1 +
 3 files changed, 47 insertions(+)

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 31c1082..3be41ee 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -199,6 +199,7 @@ 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..99394ec 100644
--- a/target-s390x/cpu.c
+++ b/target-s390x/cpu.c
@@ -32,6 +32,12 @@
 #include "trace.h"
 #ifndef CONFIG_USER_ONLY
 #include "sysemu/arch_init.h"
+#include "sysemu/sysemu.h"
+#include "hw/boards.h"
+#include "hw/s390x/sclp.h"
+#include "qom/cpu.h"
+
+#define last_cpu QTAILQ_LAST(&cpus, CPUTailQ)
 #endif
 
 #define CR0_RESET       0xE0UL
@@ -211,6 +217,12 @@ 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)
@@ -254,6 +266,39 @@ static void s390_cpu_finalize(Object *obj)
 }
 
 #if !defined(CONFIG_USER_ONLY)
+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);
+}
+#endif
+
+#if !defined(CONFIG_USER_ONLY)
 static bool disabled_wait(CPUState *cpu)
 {
     return cpu->halted && !(S390_CPU(cpu)->env.psw.mask &
diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
index 06ca60b..cf1e2bd 100644
--- a/target-s390x/cpu.h
+++ b/target-s390x/cpu.h
@@ -541,6 +541,7 @@ static inline uint8_t s390_cpu_get_state(S390CPU *cpu)
 
 void gtod_save(QEMUFile *f, void *opaque);
 int gtod_load(QEMUFile *f, void *opaque, int version_id);
+void s390_hot_add_cpu(const int64_t id, Error **errp);
 
 /* service interrupts are floating therefore we must not pass an cpustate */
 void s390_sclp_extint(uint32_t parm);
-- 
1.9.1