[Qemu-devel] [PATCH v2 05/11] pc: add cpu hot unplug request callback support

[Zhu Guihua]

Add cpu hot unplug request callback support, and a pre-check about the
active cpus is added to avoid removing the last cpu.

Signed-off-by: Zhu Guihua <zhugh.f...@cn.fujitsu.com>
Signed-off-by: Gu Zheng <guz.f...@cn.fujitsu.com>
---
 hw/i386/pc.c | 36 ++++++++++++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 9bdec16..dd6e8da 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1694,6 +1694,34 @@ out:
     error_propagate(errp, local_err);
 }
 
+static void pc_cpu_unplug_request(HotplugHandler *hotplug_dev,
+                                  DeviceState *dev, Error **errp)
+{
+    HotplugHandlerClass *hhc;
+    Error *local_err = NULL;
+    PCMachineState *pcms;
+
+    if (smp_cpus == 1) {
+        error_setg(&local_err,
+                   "This is the last cpu, should not be removed!");
+        goto out;
+    }
+
+    pcms = PC_MACHINE(hotplug_dev);
+    if (!pcms->acpi_dev) {
+        if (dev->hotplugged) {
+            error_setg(&local_err,
+                       "cpu hot unplug is not enabled: missing acpi device");
+        }
+        goto out;
+    }
+
+    hhc = HOTPLUG_HANDLER_GET_CLASS(pcms->acpi_dev);
+    hhc->unplug_request(HOTPLUG_HANDLER(pcms->acpi_dev), dev, &local_err);
+out:
+    error_propagate(errp, local_err);
+}
+
 static void pc_machine_device_plug_cb(HotplugHandler *hotplug_dev,
                                       DeviceState *dev, Error **errp)
 {
@@ -1707,8 +1735,12 @@ static void pc_machine_device_plug_cb(HotplugHandler 
*hotplug_dev,
 static void pc_machine_device_unplug_request_cb(HotplugHandler *hotplug_dev,
                                                 DeviceState *dev, Error **errp)
 {
-    error_setg(errp, "acpi: device unplug request for not supported device"
-               " type: %s", object_get_typename(OBJECT(dev)));
+    if (object_dynamic_cast(OBJECT(dev), TYPE_CPU)) {
+        pc_cpu_unplug_request(hotplug_dev, dev, errp);
+    } else {
+        error_setg(errp, "acpi: device unplug request for not supported device"
+                   " type: %s", object_get_typename(OBJECT(dev)));
+    }
 }
 
 static void pc_machine_device_unplug_cb(HotplugHandler *hotplug_dev,
-- 
1.9.3