[Qemu-devel] [PATCH 4/4] s390-hotplug: Implement hot_add_cpu hook

[Jason J. Herne]

From: "Jason J. Herne" <jjhe...@us.ibm.com>

Implement hot_add_cpu for S390 to allow hot plugging of cpus.

Signed-off-by: Jason J. Herne <jjhe...@us.ibm.com>
---
 hw/s390x/s390-virtio-ccw.c |  1 +
 target-s390x/cpu.c         | 29 +++++++++++++++++++++++++++++
 target-s390x/cpu.h         |  2 ++
 3 files changed, 32 insertions(+)

diff --git a/hw/s390x/s390-virtio-ccw.c b/hw/s390x/s390-virtio-ccw.c
index 62319b9..8b89886 100644
--- a/hw/s390x/s390-virtio-ccw.c
+++ b/hw/s390x/s390-virtio-ccw.c
@@ -132,6 +132,7 @@ static QEMUMachine ccw_machine = {
     .alias = "s390-ccw",
     .desc = "VirtIO-ccw based S390 machine",
     .init = ccw_init,
+    .hot_add_cpu = ccw_hot_add_cpu,
     .block_default_type = IF_VIRTIO,
     .no_cdrom = 1,
     .no_floppy = 1,
diff --git a/target-s390x/cpu.c b/target-s390x/cpu.c
index a6fa82c..fd667d9 100644
--- a/target-s390x/cpu.c
+++ b/target-s390x/cpu.c
@@ -27,6 +27,8 @@
 #include "qemu-common.h"
 #include "qemu/timer.h"
 #include "hw/hw.h"
+#include "hw/s390x/sclp.h"
+#include "sysemu/sysemu.h"
 #ifndef CONFIG_USER_ONLY
 #include "sysemu/arch_init.h"
 #endif
@@ -206,6 +208,33 @@ static void s390_cpu_finalize(Object *obj)
 #endif
 }
 
+#if !defined(CONFIG_USER_ONLY)
+void ccw_hot_add_cpu(const int64_t id, Error **errp)
+{
+    S390CPU *new_cpu;
+    CPUState *cpu;
+    int cpu_count = 0;
+
+    CPU_FOREACH(cpu) {
+        cpu_count++;
+    }
+
+    if (cpu_count == max_cpus) {
+        error_setg(errp, "Maximum number of cpus already defined");
+        return;
+    }
+
+    if (id != next_cpu_num) {
+        error_setg(errp, "Unable to add CPU: %" PRIi64
+                   ", The next available id is %d", id, next_cpu_num);
+        return;
+    }
+
+    new_cpu = S390_CPU(object_new(TYPE_S390_CPU));
+    object_property_set_bool(OBJECT(new_cpu), true, "realized", NULL);
+}
+#endif
+
 static const VMStateDescription vmstate_s390_cpu = {
     .name = "cpu",
     .unmigratable = 1,
diff --git a/target-s390x/cpu.h b/target-s390x/cpu.h
index 79f47b4..af199e5 100644
--- a/target-s390x/cpu.h
+++ b/target-s390x/cpu.h
@@ -377,6 +377,8 @@ S390CPU *s390_cpu_addr2state(uint16_t cpu_addr);
 void s390_add_running_cpu(S390CPU *cpu);
 unsigned s390_del_running_cpu(S390CPU *cpu);
 
+void ccw_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);
 
-- 
1.8.3.2