nvdimm: support nvdimm label

Introduce a parameter, 'label-size', which is the size of nvdimm label
data area which is reserved at the end of backend memory. It is required
at least 128k

Two callbacks, read_label_data() and write_label_data(), are used to
operate the label area

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

hw/mem/nvdimm.c

@@ -23,20 +23,152 @@
  */
 
 #include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qapi/visitor.h"
 #include "hw/mem/nvdimm.h"
 
+static void nvdimm_get_label_size(Object *obj, Visitor *v, const char *name,
+                                  void *opaque, Error **errp)
+{
+    NVDIMMDevice *nvdimm = NVDIMM(obj);
+    uint64_t value = nvdimm->label_size;
+
+    visit_type_size(v, name, &value, errp);
+}
+
+static void nvdimm_set_label_size(Object *obj, Visitor *v, const char *name,
+                                  void *opaque, Error **errp)
+{
+    NVDIMMDevice *nvdimm = NVDIMM(obj);
+    Error *local_err = NULL;
+    uint64_t value;
+
+    if (memory_region_size(&nvdimm->nvdimm_mr)) {
+        error_setg(&local_err, "cannot change property value");
+        goto out;
+    }
+
+    visit_type_size(v, name, &value, &local_err);
+    if (local_err) {
+        goto out;
+    }
+    if (value < MIN_NAMESPACE_LABEL_SIZE) {
+        error_setg(&local_err, "Property '%s.%s' (0x%" PRIx64 ") is required"
+                   " at least 0x%lx", object_get_typename(obj),
+                   name, value, MIN_NAMESPACE_LABEL_SIZE);
+        goto out;
+    }
+
+    nvdimm->label_size = value;
+out:
+    error_propagate(errp, local_err);
+}
+
+static void nvdimm_init(Object *obj)
+{
+    object_property_add(obj, "label-size", "int",
+                        nvdimm_get_label_size, nvdimm_set_label_size, NULL,
+                        NULL, 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 align, pmem_size, size = memory_region_size(mr);
+
+    align = memory_region_get_alignment(mr);
+
+    pmem_size = size - nvdimm->label_size;
+    nvdimm->label_data = memory_region_get_ram_ptr(mr) + pmem_size;
+    pmem_size = QEMU_ALIGN_DOWN(pmem_size, align);
+
+    if (size <= nvdimm->label_size || !pmem_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 ") and "
+                   "aligned PMEM (0x%" PRIx64 ")",
+                   path, memory_region_size(mr), nvdimm->label_size, align);
+        return;
+    }
+
+    memory_region_init_alias(&nvdimm->nvdimm_mr, OBJECT(dimm),
+                             "nvdimm-memory", mr, 0, pmem_size);
+    nvdimm->nvdimm_mr.align = align;
+}
+
+/*
+ * the caller should check the input parameters before calling
+ * label read/write functions.
+ */
+static void nvdimm_validate_rw_label_data(NVDIMMDevice *nvdimm, uint64_t size,
+                                        uint64_t offset)
+{
+    assert((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_validate_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_validate_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 MemoryRegion *nvdimm_get_vmstate_memory_region(PCDIMMDevice *dimm)
+{
+    return host_memory_backend_get_memory(dimm->hostmem, &error_abort);
+}
+
 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;
+
+    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)

include/hw/mem/nvdimm.h

@@ -34,7 +34,60 @@
         }                                                     \
     } 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 */
+
+    /*
+     * 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"