[04/15] nvdimm: support nvdimm label

diff --git a/hw/mem/nvdimm.c b/hw/mem/nvdimm.c
index 0a602f2..921e6a1 100644
--- a/hw/mem/nvdimm.c
+++ b/hw/mem/nvdimm.c
@@ -25,18 +25,113 @@ 
 #include "qemu/osdep.h"
 #include "hw/mem/nvdimm.h"
 
+static bool nvdimm_get_reserve_label(Object *obj, Error **errp)
+{
+    NVDIMMDevice *nvdimm = NVDIMM(obj);
+
+    return nvdimm->reserve_label;
+}
+
+static void nvdimm_set_reserve_label(Object *obj, bool value, Error **errp)
+{
+    NVDIMMDevice *nvdimm = NVDIMM(obj);
+
+    nvdimm->reserve_label = value;
+}
+
+static void nvdimm_init(Object *obj)
+{
+    object_property_add_bool(obj, "reserve-label", nvdimm_get_reserve_label,
+                             nvdimm_set_reserve_label, NULL);
+}
+
+static MemoryRegion *nvdimm_get_memory_region(PCDIMMDevice *dimm)
+{
+    NVDIMMDevice *nvdimm = NVDIMM(dimm);
+
+    return &nvdimm->nvdimm_mr;
+}
+
+static void nvdimm_realize(PCDIMMDevice *dimm, Error **errp)
+{
+    MemoryRegion *mr = host_memory_backend_get_memory(dimm->hostmem, errp);
+    NVDIMMDevice *nvdimm = NVDIMM(dimm);
+    uint64_t size = memory_region_size(mr);
+
+    nvdimm->label_size = nvdimm->reserve_label ? MIN_NAMESPACE_LABEL_SIZE : 0;
+
+    if (size <= nvdimm->label_size) {
+        HostMemoryBackend *hostmem = dimm->hostmem;
+        char *path = object_get_canonical_path_component(OBJECT(hostmem));
+
+        error_setg(errp, "the size of memdev %s (0x%" PRIx64 ") is too"
+                   "small to contain nvdimm label (0x%" PRIx64 ")",
+                   path, memory_region_size(mr), nvdimm->label_size);
+        return;
+    }
+
+    size -= nvdimm->label_size;
+    memory_region_init_alias(&nvdimm->nvdimm_mr, OBJECT(dimm),
+                             "nvdimm-memory", mr, 0, size);
+    nvdimm->nvdimm_mr.align = memory_region_get_alignment(mr);
+
+    nvdimm->label_data = memory_region_get_ram_ptr(mr) + size;
+}
+
+static void nvdimm_assert_rw_label_data(NVDIMMDevice *nvdimm, uint64_t size,
+                                        uint64_t offset)
+{
+    assert(nvdimm->reserve_label &&
+           (nvdimm->label_size >= size + offset) && (offset + size > offset));
+}
+
+static void nvdimm_read_label_data(NVDIMMDevice *nvdimm, void *buf,
+                                   uint64_t size, uint64_t offset)
+{
+    nvdimm_assert_rw_label_data(nvdimm, size, offset);
+
+    memcpy(buf, nvdimm->label_data + offset, size);
+}
+
+static void nvdimm_write_label_data(NVDIMMDevice *nvdimm, const void *buf,
+                                    uint64_t size, uint64_t offset)
+{
+    MemoryRegion *mr;
+    PCDIMMDevice *dimm = PC_DIMM(nvdimm);
+    uint64_t backend_offset;
+
+    nvdimm_assert_rw_label_data(nvdimm, size, offset);
+
+    memcpy(nvdimm->label_data + offset, buf, size);
+
+    mr = host_memory_backend_get_memory(dimm->hostmem, &error_abort);
+    backend_offset = memory_region_size(mr) - nvdimm->label_size + offset;
+    memory_region_set_dirty(mr, backend_offset, size);
+}
+
 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;
+
+    nvc->read_label_data = nvdimm_read_label_data;
+    nvc->write_label_data = nvdimm_write_label_data;
 }
 
 static TypeInfo nvdimm_info = {
     .name          = TYPE_NVDIMM,
     .parent        = TYPE_PC_DIMM,
+    .class_size    = sizeof(NVDIMMClass),
     .class_init    = nvdimm_class_init,
+    .instance_size = sizeof(NVDIMMDevice),
+    .instance_init = nvdimm_init,
 };
 
 static void nvdimm_register_types(void)
diff --git a/include/hw/mem/nvdimm.h b/include/hw/mem/nvdimm.h
index 517de9c..bb5c74a 100644
--- a/include/hw/mem/nvdimm.h
+++ b/include/hw/mem/nvdimm.h
@@ -33,7 +33,66 @@ 
         }                                                     \
     } while (0)
 
-#define TYPE_NVDIMM             "nvdimm"
+/*
+ * The minimum label data size is required by NVDIMM Namespace
+ * specification, see the chapter 2 Namespaces:
+ *   "NVDIMMs following the NVDIMM Block Mode Specification use an area
+ *    at least 128KB in size, which holds around 1000 labels."
+ */
+#define MIN_NAMESPACE_LABEL_SIZE      (128UL << 10)
+
+#define TYPE_NVDIMM      "nvdimm"
+#define NVDIMM(obj)      OBJECT_CHECK(NVDIMMDevice, (obj), TYPE_NVDIMM)
+#define NVDIMM_CLASS(oc) OBJECT_CLASS_CHECK(NVDIMMClass, (oc), TYPE_NVDIMM)
+#define NVDIMM_GET_CLASS(obj) OBJECT_GET_CLASS(NVDIMMClass, (obj), \
+                                               TYPE_NVDIMM)
+struct NVDIMMDevice {
+    /* private */
+    PCDIMMDevice parent_obj;
+
+    /* public */
+
+    /*
+     * if we need to reserve memory region for NVDIMM label at the
+     * end of backend memory?
+     */
+    bool reserve_label;
+
+    /*
+     * the size of label data in NVDIMM device which is presented to
+     * guest via __DSM "Get Namespace Label Size" function.
+     */
+    uint64_t label_size;
+
+    /*
+     * the address of label data which is read by __DSM "Get Namespace
+     * Label Data" function and written by __DSM "Set Namespace Label
+     * Data" function.
+     */
+    void *label_data;
+
+    /*
+     * it's the PMEM region in NVDIMM device, which is presented to
+     * guest via ACPI NFIT and _FIT method if NVDIMM hotplug is supported.
+     */
+    MemoryRegion nvdimm_mr;
+};
+typedef struct NVDIMMDevice NVDIMMDevice;
+
+struct NVDIMMClass {
+    /* private */
+    PCDIMMDeviceClass parent_class;
+
+    /* public */
+
+    /* read @size bytes from NVDIMM label data at @offset into @buf. */
+    void (*read_label_data)(NVDIMMDevice *nvdimm, void *buf,
+                            uint64_t size, uint64_t offset);
+    /* write @size bytes from @buf to NVDIMM label data at @offset. */
+    void (*write_label_data)(NVDIMMDevice *nvdimm, const void *buf,
+                             uint64_t size, uint64_t offset);
+};
+typedef struct NVDIMMClass NVDIMMClass;
 
 #define NVDIMM_DSM_MEM_FILE     "etc/acpi/nvdimm-mem"