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, 19 insertions, 0 deletions

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index f56ea0f87b..b395717b07 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -1721,6 +1721,16 @@ out:
     error_propagate(errp, local_err);
 }
 
+static void pc_dimm_post_plug(HotplugHandler *hotplug_dev,
+                              DeviceState *dev, Error **errp)
+{
+    PCMachineState *pcms = PC_MACHINE(hotplug_dev);
+
+    if (object_dynamic_cast(OBJECT(dev), TYPE_NVDIMM)) {
+        nvdimm_acpi_hotplug(&pcms->acpi_nvdimm_state);
+    }
+}
+
 static void pc_dimm_unplug_request(HotplugHandler *hotplug_dev,
                                    DeviceState *dev, Error **errp)
 {
@@ -1986,6 +1996,14 @@ static void pc_machine_device_plug_cb(HotplugHandler *hotplug_dev,
     }
 }
 
+static void pc_machine_device_post_plug_cb(HotplugHandler *hotplug_dev,
+                                           DeviceState *dev, Error **errp)
+{
+    if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
+        pc_dimm_post_plug(hotplug_dev, dev, errp);
+    }
+}
+
 static void pc_machine_device_unplug_request_cb(HotplugHandler *hotplug_dev,
                                                 DeviceState *dev, Error **errp)
 {
@@ -2290,6 +2308,7 @@ static void pc_machine_class_init(ObjectClass *oc, void *data)
     mc->reset = pc_machine_reset;
     hc->pre_plug = pc_machine_device_pre_plug_cb;
     hc->plug = pc_machine_device_plug_cb;
+    hc->post_plug = pc_machine_device_post_plug_cb;
     hc->unplug_request = pc_machine_device_unplug_request_cb;
     hc->unplug = pc_machine_device_unplug_cb;
     nc->nmi_monitor_handler = x86_nmi;