pc: memhp: enable nvdimm device hotplug

_GPE.E04 is dedicated for nvdimm device hotplug

Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

docs/specs/acpi_mem_hotplug.txt

@@ -4,6 +4,9 @@ QEMU<->ACPI BIOS memory hotplug interface
 ACPI BIOS GPE.3 handler is dedicated for notifying OS about memory hot-add
 and hot-remove events.
 
+ACPI BIOS GPE.4 handler is dedicated for notifying OS about nvdimm device
+hot-add and hot-remove events.
+
 Memory hot-plug interface (IO port 0xa00-0xa17, 1-4 byte access):
 ---------------------------------------------------------------
 0xa00:

hw/acpi/memory_hotplug.c

@@ -2,6 +2,7 @@
 #include "hw/acpi/memory_hotplug.h"
 #include "hw/acpi/pc-hotplug.h"
 #include "hw/mem/pc-dimm.h"
+#include "hw/mem/nvdimm.h"
 #include "hw/boards.h"
 #include "hw/qdev-core.h"
 #include "trace.h"
@@ -232,11 +233,8 @@ void acpi_memory_plug_cb(HotplugHandler *hotplug_dev, MemHotplugState *mem_st,
                          DeviceState *dev, Error **errp)
 {
     MemStatus *mdev;
-    DeviceClass *dc = DEVICE_GET_CLASS(dev);
-
-    if (!dc->hotpluggable) {
-        return;
-    }
+    AcpiEventStatusBits event;
+    bool is_nvdimm = object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM);
 
     mdev = acpi_memory_slot_status(mem_st, dev, errp);
     if (!mdev) {
@@ -244,10 +242,23 @@ void acpi_memory_plug_cb(HotplugHandler *hotplug_dev, MemHotplugState *mem_st,
     }
 
     mdev->dimm = dev;
-    mdev->is_enabled = true;
+
+    /*
+     * do not set is_enabled and is_inserting if the slot is plugged with
+     * a nvdimm device to stop OSPM inquires memory region from the slot.
+     */
+    if (is_nvdimm) {
+        event = ACPI_NVDIMM_HOTPLUG_STATUS;
+    } else {
+        mdev->is_enabled = true;
+        event = ACPI_MEMORY_HOTPLUG_STATUS;
+    }
+
     if (dev->hotplugged) {
-        mdev->is_inserting = true;
-        acpi_send_event(DEVICE(hotplug_dev), ACPI_MEMORY_HOTPLUG_STATUS);
+        if (!is_nvdimm) {
+            mdev->is_inserting = true;
+        }
+        acpi_send_event(DEVICE(hotplug_dev), event);
     }
 }
 
@@ -262,6 +273,8 @@ void acpi_memory_unplug_request_cb(HotplugHandler *hotplug_dev,
         return;
     }
 
+    /* nvdimm device hot unplug is not supported yet. */
+    assert(!object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM));
     mdev->is_removing = true;
     acpi_send_event(DEVICE(hotplug_dev), ACPI_MEMORY_HOTPLUG_STATUS);
 }
@@ -276,6 +289,8 @@ void acpi_memory_unplug_cb(MemHotplugState *mem_st,
         return;
     }
 
+    /* nvdimm device hot unplug is not supported yet. */
+    assert(!object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM));
     mdev->is_enabled = false;
     mdev->dimm = NULL;
 }

hw/i386/acpi-build.c

@@ -2069,6 +2069,13 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
         method = aml_method("_E03", 0, AML_NOTSERIALIZED);
         aml_append(method, aml_call0(MEMORY_HOTPLUG_HANDLER_PATH));
         aml_append(scope, method);
+
+        if (pcms->acpi_nvdimm_state.is_enabled) {
+            method = aml_method("_E04", 0, AML_NOTSERIALIZED);
+            aml_append(method, aml_notify(aml_name("\\_SB.NVDR"),
+                                          aml_int(0x80)));
+            aml_append(scope, method);
+        }
     }
     aml_append(dsdt, scope);
 

hw/i386/pc.c

@@ -1744,6 +1744,12 @@ static void pc_dimm_unplug_request(HotplugHandler *hotplug_dev,
         goto out;
     }
 
+    if (object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM)) {
+        error_setg(&local_err,
+                   "nvdimm device hot unplug is not supported yet.");
+        goto out;
+    }
+
     hhc = HOTPLUG_HANDLER_GET_CLASS(pcms->acpi_dev);
     hhc->unplug_request(HOTPLUG_HANDLER(pcms->acpi_dev), dev, &local_err);
 
@@ -1761,6 +1767,12 @@ static void pc_dimm_unplug(HotplugHandler *hotplug_dev,
     HotplugHandlerClass *hhc;
     Error *local_err = NULL;
 
+    if (object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM)) {
+        error_setg(&local_err,
+                   "nvdimm device hot unplug is not supported yet.");
+        goto out;
+    }
+
     hhc = HOTPLUG_HANDLER_GET_CLASS(pcms->acpi_dev);
     hhc->unplug(HOTPLUG_HANDLER(pcms->acpi_dev), dev, &local_err);
 

hw/mem/nvdimm.c

@@ -148,13 +148,9 @@ static MemoryRegion *nvdimm_get_vmstate_memory_region(PCDIMMDevice *dimm)
 
 static void nvdimm_class_init(ObjectClass *oc, void *data)
 {
-    DeviceClass *dc = DEVICE_CLASS(oc);
     PCDIMMDeviceClass *ddc = PC_DIMM_CLASS(oc);
     NVDIMMClass *nvc = NVDIMM_CLASS(oc);
 
-    /* nvdimm hotplug has not been supported yet. */
-    dc->hotpluggable = false;
-
     ddc->realize = nvdimm_realize;
     ddc->get_memory_region = nvdimm_get_memory_region;
     ddc->get_vmstate_memory_region = nvdimm_get_vmstate_memory_region;

include/hw/acpi/acpi_dev_interface.h

@@ -10,6 +10,7 @@ typedef enum {
     ACPI_PCI_HOTPLUG_STATUS = 2,
     ACPI_CPU_HOTPLUG_STATUS = 4,
     ACPI_MEMORY_HOTPLUG_STATUS = 8,
+    ACPI_NVDIMM_HOTPLUG_STATUS = 16,
 } AcpiEventStatusBits;
 
 #define TYPE_ACPI_DEVICE_IF "acpi-device-interface"