[v6,3/8] acpi, mem-hotplug: add unplug request cb for memory device

diff --git a/hw/acpi/ich9.c b/hw/acpi/ich9.c
index 5352e19..b85eed4 100644
--- a/hw/acpi/ich9.c
+++ b/hw/acpi/ich9.c
@@ -400,8 +400,14 @@  void ich9_pm_device_plug_cb(ICH9LPCPMRegs *pm, DeviceState *dev, Error **errp)
 void ich9_pm_device_unplug_request_cb(ICH9LPCPMRegs *pm, DeviceState *dev,
                                       Error **errp)
 {
-    error_setg(errp, "acpi: device unplug request for not supported device"
-               " type: %s", object_get_typename(OBJECT(dev)));
+    if (pm->acpi_memory_hotplug.is_enabled &&
+        object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
+        acpi_memory_unplug_request_cb(&pm->acpi_regs, pm->irq,
+                                      &pm->acpi_memory_hotplug, dev, errp);
+    } else {
+        error_setg(errp, "acpi: device unplug request for not supported device"
+                   " type: %s", object_get_typename(OBJECT(dev)));
+    }
 }
 
 void ich9_pm_device_unplug_cb(ICH9LPCPMRegs *pm, DeviceState *dev,
diff --git a/hw/acpi/memory_hotplug.c b/hw/acpi/memory_hotplug.c
index 6af9303..42fe668 100644
--- a/hw/acpi/memory_hotplug.c
+++ b/hw/acpi/memory_hotplug.c
@@ -75,6 +75,7 @@  static uint64_t acpi_memory_hotplug_read(void *opaque, hwaddr addr,
     case 0x14: /* pack and return is_* fields */
         val |= mdev->is_enabled   ? 1 : 0;
         val |= mdev->is_inserting ? 2 : 0;
+        val |= mdev->is_removing  ? 4 : 0;
         trace_mhp_acpi_read_flags(mem_st->selector, val);
         break;
     default:
@@ -218,6 +219,24 @@  void acpi_memory_plug_cb(ACPIREGS *ar, qemu_irq irq, MemHotplugState *mem_st,
     return;
 }
 
+void acpi_memory_unplug_request_cb(ACPIREGS *ar, qemu_irq irq,
+                                   MemHotplugState *mem_st,
+                                   DeviceState *dev, Error **errp)
+{
+    MemStatus *mdev;
+
+    mdev = acpi_memory_slot_status(mem_st, dev, errp);
+    if (!mdev) {
+        return;
+    }
+
+    mdev->is_removing = true;
+
+    /* Do ACPI magic */
+    ar->gpe.sts[0] |= ACPI_MEMORY_HOTPLUG_STATUS;
+    acpi_update_sci(ar, irq);
+}
+
 static const VMStateDescription vmstate_memhp_sts = {
     .name = "memory hotplug device state",
     .version_id = 1,
diff --git a/hw/acpi/piix4.c b/hw/acpi/piix4.c
index d1f1179..f716e91 100644
--- a/hw/acpi/piix4.c
+++ b/hw/acpi/piix4.c
@@ -361,7 +361,11 @@  static void piix4_device_unplug_request_cb(HotplugHandler *hotplug_dev,
 {
     PIIX4PMState *s = PIIX4_PM(hotplug_dev);
 
-    if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
+    if (s->acpi_memory_hotplug.is_enabled &&
+        object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
+        acpi_memory_unplug_request_cb(&s->ar, s->irq, &s->acpi_memory_hotplug,
+                                      dev, errp);
+    } else if (object_dynamic_cast(OBJECT(dev), TYPE_PCI_DEVICE)) {
         acpi_pcihp_device_unplug_cb(&s->ar, s->irq, &s->acpi_pci_hotplug, dev,
                                     errp);
     } else {
diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index a8e6be1..9b0859c 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1677,6 +1677,26 @@  out:
     error_propagate(errp, local_err);
 }
 
+static void pc_dimm_unplug_request(HotplugHandler *hotplug_dev,
+                                   DeviceState *dev, Error **errp)
+{
+    HotplugHandlerClass *hhc;
+    Error *local_err = NULL;
+    PCMachineState *pcms = PC_MACHINE(hotplug_dev);
+
+    if (!pcms->acpi_dev) {
+        error_setg(&local_err,
+                   "memory hotplug 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_cpu_plug(HotplugHandler *hotplug_dev,
                         DeviceState *dev, Error **errp)
 {
@@ -1719,8 +1739,12 @@  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_PC_DIMM)) {
+        pc_dimm_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,
diff --git a/include/hw/acpi/memory_hotplug.h b/include/hw/acpi/memory_hotplug.h
index 7bbf8a0..9d7eee9 100644
--- a/include/hw/acpi/memory_hotplug.h
+++ b/include/hw/acpi/memory_hotplug.h
@@ -7,10 +7,17 @@ 
 
 #define ACPI_MEMORY_HOTPLUG_STATUS 8
 
+/**
+ * MemStatus:
+ * @is_removing: the memory device in slot has been requested to be ejected.
+ *
+ * This structure stores memory device's status.
+ */
 typedef struct MemStatus {
     DeviceState *dimm;
     bool is_enabled;
     bool is_inserting;
+    bool is_removing;
     uint32_t ost_event;
     uint32_t ost_status;
 } MemStatus;
@@ -28,6 +35,9 @@  void acpi_memory_hotplug_init(MemoryRegion *as, Object *owner,
 
 void acpi_memory_plug_cb(ACPIREGS *ar, qemu_irq irq, MemHotplugState *mem_st,
                          DeviceState *dev, Error **errp);
+void acpi_memory_unplug_request_cb(ACPIREGS *ar, qemu_irq irq,
+                                   MemHotplugState *mem_st,
+                                   DeviceState *dev, Error **errp);
 
 extern const VMStateDescription vmstate_memory_hotplug;
 #define VMSTATE_MEMORY_HOTPLUG(memhp, state) \