nvdimm acpi: introduce fit buffer

The buffer is used to save the FIT info for all the presented nvdimm
devices which is updated after the nvdimm device is plugged or
unplugged. In the later patch, it will be used to construct NVDIMM
ACPI _FIT method which reflects the presented nvdimm devices after
nvdimm hotplug

As FIT buffer can not completely mapped into guest address space,
OSPM will exit to QEMU multiple times, however, there is the race
condition - FIT may be changed during these multiple exits, so that
some rules are introduced:
1) the user should hold the @lock to access the buffer and
2) mark @dirty whenever the buffer is updated.

@dirty is cleared for the first time OSPM gets fit buffer, if
dirty is detected in the later access, OSPM will restart the
access

As fit should be updated after nvdimm device is successfully realized
so that a new hotplug callback, post_hotplug, is introduced

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>

1 files changed, 10 insertions, 0 deletions

diff --git a/include/hw/hotplug.h b/include/hw/hotplug.h
index c0db869f85..10ca5b6504 100644
--- a/include/hw/hotplug.h
+++ b/include/hw/hotplug.h
@@ -47,6 +47,7 @@ typedef void (*hotplug_fn)(HotplugHandler *plug_handler,
  * @parent: Opaque parent interface.
  * @pre_plug: pre plug callback called at start of device.realize(true)
  * @plug: plug callback called at end of device.realize(true).
+ * @post_pug: post plug callback called after device is successfully plugged.
  * @unplug_request: unplug request callback.
  *                  Used as a means to initiate device unplug for devices that
  *                  require asynchronous unplug handling.
@@ -61,6 +62,7 @@ typedef struct HotplugHandlerClass {
     /* <public> */
     hotplug_fn pre_plug;
     hotplug_fn plug;
+    hotplug_fn post_plug;
     hotplug_fn unplug_request;
     hotplug_fn unplug;
 } HotplugHandlerClass;
@@ -83,6 +85,14 @@ void hotplug_handler_pre_plug(HotplugHandler *plug_handler,
                               DeviceState *plugged_dev,
                               Error **errp);
 
+/**
+ * hotplug_handler_post_plug:
+ *
+ * Call #HotplugHandlerClass.post_plug callback of @plug_handler.
+ */
+void hotplug_handler_post_plug(HotplugHandler *plug_handler,
+                               DeviceState *plugged_dev,
+                               Error **errp);
 
 /**
  * hotplug_handler_unplug_request: