[v5,1/5] nvdimm acpi: prebuild nvdimm devices for available slots

diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
index bb896c9..58bc5c6 100644
--- a/hw/acpi/nvdimm.c
+++ b/hw/acpi/nvdimm.c
@@ -961,12 +961,11 @@  static void nvdimm_build_device_dsm(Aml *dev, uint32_t handle)
     aml_append(dev, method);
 }
 
-static void nvdimm_build_nvdimm_devices(GSList *device_list, Aml *root_dev)
+static void nvdimm_build_nvdimm_devices(Aml *root_dev, uint32_t ram_slots)
 {
-    for (; device_list; device_list = device_list->next) {
-        DeviceState *dev = device_list->data;
-        int slot = object_property_get_int(OBJECT(dev), PC_DIMM_SLOT_PROP,
-                                           NULL);
+    uint32_t slot;
+
+    for (slot = 0; slot < ram_slots; slot++) {
         uint32_t handle = nvdimm_slot_to_handle(slot);
         Aml *nvdimm_dev;
 
@@ -987,9 +986,9 @@  static void nvdimm_build_nvdimm_devices(GSList *device_list, Aml *root_dev)
     }
 }
 
-static void nvdimm_build_ssdt(GSList *device_list, GArray *table_offsets,
-                              GArray *table_data, BIOSLinker *linker,
-                              GArray *dsm_dma_arrea)
+static void nvdimm_build_ssdt(GArray *table_offsets, GArray *table_data,
+                              BIOSLinker *linker, GArray *dsm_dma_arrea,
+                              uint32_t ram_slots)
 {
     Aml *ssdt, *sb_scope, *dev;
     int mem_addr_offset, nvdimm_ssdt;
@@ -1021,7 +1020,7 @@  static void nvdimm_build_ssdt(GSList *device_list, GArray *table_offsets,
     /* 0 is reserved for root device. */
     nvdimm_build_device_dsm(dev, 0);
 
-    nvdimm_build_nvdimm_devices(device_list, dev);
+    nvdimm_build_nvdimm_devices(dev, ram_slots);
 
     aml_append(sb_scope, dev);
     aml_append(ssdt, sb_scope);
@@ -1046,17 +1045,25 @@  static void nvdimm_build_ssdt(GSList *device_list, GArray *table_offsets,
 }
 
 void nvdimm_build_acpi(GArray *table_offsets, GArray *table_data,
-                       BIOSLinker *linker, GArray *dsm_dma_arrea)
+                       BIOSLinker *linker, GArray *dsm_dma_arrea,
+                       uint32_t ram_slots)
 {
     GSList *device_list;
 
-    /* no NVDIMM device is plugged. */
+    /* no nvdimm device can be plugged. */
+    if (!ram_slots) {
+        return;
+    }
+
+    nvdimm_build_ssdt(table_offsets, table_data, linker, dsm_dma_arrea,
+                      ram_slots);
+
     device_list = nvdimm_get_plugged_device_list();
+    /* no NVDIMM device is plugged. */
     if (!device_list) {
         return;
     }
+
     nvdimm_build_nfit(device_list, table_offsets, table_data, linker);
-    nvdimm_build_ssdt(device_list, table_offsets, table_data, linker,
-                      dsm_dma_arrea);
     g_slist_free(device_list);
 }
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index e999654..6ae4769 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -2767,7 +2767,7 @@  void acpi_build(AcpiBuildTables *tables, MachineState *machine)
     }
     if (pcms->acpi_nvdimm_state.is_enabled) {
         nvdimm_build_acpi(table_offsets, tables_blob, tables->linker,
-                          pcms->acpi_nvdimm_state.dsm_mem);
+                          pcms->acpi_nvdimm_state.dsm_mem, machine->ram_slots);
     }
 
     /* Add tables supplied by user (if any) */
diff --git a/include/hw/mem/nvdimm.h b/include/hw/mem/nvdimm.h
index 1cfe9e0..63a2b20 100644
--- a/include/hw/mem/nvdimm.h
+++ b/include/hw/mem/nvdimm.h
@@ -112,5 +112,6 @@  typedef struct AcpiNVDIMMState AcpiNVDIMMState;
 void nvdimm_init_acpi_state(AcpiNVDIMMState *state, MemoryRegion *io,
                             FWCfgState *fw_cfg, Object *owner);
 void nvdimm_build_acpi(GArray *table_offsets, GArray *table_data,
-                       BIOSLinker *linker, GArray *dsm_dma_arrea);
+                       BIOSLinker *linker, GArray *dsm_dma_arrea,
+                       uint32_t ram_slots);
 #endif