[PATCH v6 31/33] nvdimm: allow using whole backend memory as pmem

From: Xiao Guangrong <guangrong.xiao@linux.intel.com>
To: pbonzini@redhat.com, imammedo@redhat.com
Cc: gleb@kernel.org, mtosatti@redhat.com, stefanha@redhat.com,
	mst@redhat.com, rth@twiddle.net, ehabkost@redhat.com,
	dan.j.williams@intel.com, kvm@vger.kernel.org,
	qemu-devel@nongnu.org,
	Xiao Guangrong <guangrong.xiao@linux.intel.com>
Subject: [PATCH v6 31/33] nvdimm: allow using whole backend memory as pmem
Date: Fri, 30 Oct 2015 13:56:25 +0800	[thread overview]
Message-ID: <1446184587-142784-32-git-send-email-guangrong.xiao@linux.intel.com> (raw)
In-Reply-To: <1446184587-142784-1-git-send-email-guangrong.xiao@linux.intel.com>

Introduce a parameter, named "reserve-label-data", if it is
false which indicates that QEMU does not reserve any region
on the backend memory to support label data. It is a
'label-less' NVDIMM device mode that linux will use whole
memory on the device as a single namesapce

This is useful for the users who want to pass whole nvdimm
device and make its data completely be visible to guest

The parameter is false on default

Signed-off-by: Xiao Guangrong <guangrong.xiao@linux.intel.com>
---
 hw/acpi/nvdimm.c        | 12 ++++++++++++
 hw/mem/nvdimm.c         | 43 ++++++++++++++++++++++++++++++++++++-------
 include/hw/mem/nvdimm.h |  6 ++++++
 3 files changed, 54 insertions(+), 7 deletions(-)

diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
index 5c8be41..f8d7d19 100644
--- a/hw/acpi/nvdimm.c
+++ b/hw/acpi/nvdimm.c
@@ -531,6 +531,12 @@ static void nvdimm_dsm_func_label_size(NVDIMMDevice *nvdimm, GArray *out)
 static uint32_t nvdimm_rw_label_data_check(NVDIMMDevice *nvdimm,
                                            uint32_t offset, uint32_t length)
 {
+    if (!nvdimm->reserve_label_data) {
+        nvdimm_debug("read/write label request on the device without "
+                     "label data reserved.\n");
+        return NVDIMM_DSM_STATUS_NOT_SUPPORTED;
+    }
+
     if (offset + length < offset) {
         nvdimm_debug("offset %#x + length %#x is overflow.\n", offset,
                      length);
@@ -637,6 +643,12 @@ static void nvdimm_dsm_device(NvdimmDsmIn *in, GArray *out)
                                1 << 4 /* Get Namespace Label Size */ |
                                1 << 5 /* Get Namespace Label Data */ |
                                1 << 6 /* Set Namespace Label Data */);
+
+        /* no function support if the device does not have label data. */
+        if (!nvdimm->reserve_label_data) {
+            cmd_list = cpu_to_le64(0);
+        }
+
         build_append_int_noprefix(out, cmd_list, sizeof(cmd_list));
         goto free;
     case 0x4 /* Get Namespace Label Size */:
diff --git a/hw/mem/nvdimm.c b/hw/mem/nvdimm.c
index 185aa1a..1d89165 100644
--- a/hw/mem/nvdimm.c
+++ b/hw/mem/nvdimm.c
@@ -36,14 +36,15 @@ static void nvdimm_realize(DIMMDevice *dimm, Error **errp)
 {
     MemoryRegion *mr;
     NVDIMMDevice *nvdimm = NVDIMM(dimm);
-    uint64_t size;
+    uint64_t reserved_label_size, size;
 
     nvdimm->label_size = MIN_NAMESPACE_LABEL_SIZE;
+    reserved_label_size = nvdimm->reserve_label_data ? nvdimm->label_size : 0;
 
     mr = host_memory_backend_get_memory(dimm->hostmem, errp);
     size = memory_region_size(mr);
 
-    if (size <= nvdimm->label_size) {
+    if (size <= reserved_label_size) {
         char *path = object_get_canonical_path_component(OBJECT(dimm->hostmem));
         error_setg(errp, "the size of memdev %s (0x%" PRIx64 ") is too small"
                    " to contain nvdimm namespace label (0x%" PRIx64 ")", path,
@@ -52,15 +53,19 @@ static void nvdimm_realize(DIMMDevice *dimm, Error **errp)
     }
 
     memory_region_init_alias(&nvdimm->nvdimm_mr, OBJECT(dimm), "nvdimm-memory",
-                             mr, 0, size - nvdimm->label_size);
-    nvdimm->label_data = memory_region_get_ram_ptr(mr) +
-                         memory_region_size(&nvdimm->nvdimm_mr);
+                             mr, 0, size - reserved_label_size);
+
+    if (reserved_label_size) {
+        nvdimm->label_data = memory_region_get_ram_ptr(mr) +
+                             memory_region_size(&nvdimm->nvdimm_mr);
+    }
 }
 
 static void nvdimm_read_label_data(NVDIMMDevice *nvdimm, void *buf,
                                    uint64_t size, uint64_t offset)
 {
-    assert((nvdimm->label_size >= size + offset) && (offset + size > offset));
+    assert(nvdimm->reserve_label_data &&
+           (nvdimm->label_size >= size + offset) && (offset + size > offset));
 
     memcpy(buf, nvdimm->label_data + offset, size);
 }
@@ -72,7 +77,8 @@ static void nvdimm_write_label_data(NVDIMMDevice *nvdimm, const void *buf,
     DIMMDevice *dimm = DIMM(nvdimm);
     uint64_t backend_offset;
 
-    assert((nvdimm->label_size >= size + offset) && (offset + size > offset));
+    assert(nvdimm->reserve_label_data &&
+           (nvdimm->label_size >= size + offset) && (offset + size > offset));
 
     memcpy(nvdimm->label_data + offset, buf, size);
 
@@ -97,10 +103,33 @@ static void nvdimm_class_init(ObjectClass *oc, void *data)
     nvc->write_label_data = nvdimm_write_label_data;
 }
 
+static bool nvdimm_get_reserve_label_data(Object *obj, Error **errp)
+{
+    NVDIMMDevice *nvdimm = NVDIMM(obj);
+
+    return nvdimm->reserve_label_data;
+}
+
+static void
+nvdimm_set_reserve_label_data(Object *obj, bool value, Error **errp)
+{
+    NVDIMMDevice *nvdimm = NVDIMM(obj);
+
+    nvdimm->reserve_label_data = value;
+}
+
+static void nvdimm_init(Object *obj)
+{
+    object_property_add_bool(obj, "reserve-label-data",
+                             nvdimm_get_reserve_label_data,
+                             nvdimm_set_reserve_label_data, NULL);
+}
+
 static TypeInfo nvdimm_info = {
     .name          = TYPE_NVDIMM,
     .parent        = TYPE_DIMM,
     .instance_size = sizeof(NVDIMMDevice),
+    .instance_init = nvdimm_init,
     .class_init    = nvdimm_class_init,
     .class_size    = sizeof(NVDIMMClass),
 };
diff --git a/include/hw/mem/nvdimm.h b/include/hw/mem/nvdimm.h
index 7fdf591..b6ac266 100644
--- a/include/hw/mem/nvdimm.h
+++ b/include/hw/mem/nvdimm.h
@@ -63,6 +63,12 @@ struct NVDIMMDevice {
     /* public */
 
     /*
+     * if we need to reserve memory region for NVDIMM label data at
+     * the end of backend memory?
+     */
+    bool reserve_label_data;
+
+    /*
      * the size of label data in NVDIMM device which is presented to
      * guest via __DSM "Get Namespace Label Size" command.
      */
-- 
1.8.3.1

