[RFC QEMU PATCH 8/8] qmp: add a qmp command 'query-nvdimms' to get plugged NVDIMM devices

[Haozhong Zhang <haozhong.zhang@intel.com>]

Xen uses this command to get the backend resource, guest SPA and size of
NVDIMM devices so as to map them to guest.

Signed-off-by: Haozhong Zhang <haozhong.zhang@intel.com>
---
Cc: Markus Armbruster <armbru@redhat.com>
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>
Cc: Igor Mammedov <imammedo@redhat.com>
Cc: Eric Blake <eblake@redhat.com>
---
 docs/qmp-commands.txt   | 36 ++++++++++++++++++++++++++++++++++++
 hw/acpi/nvdimm.c        |  2 +-
 hw/mem/nvdimm.c         | 35 +++++++++++++++++++++++++++++++++++
 include/hw/mem/nvdimm.h | 10 ++++++++++
 qapi-schema.json        | 29 +++++++++++++++++++++++++++++
 5 files changed, 111 insertions(+), 1 deletion(-)

diff --git a/docs/qmp-commands.txt b/docs/qmp-commands.txt
index e0adceb..90e9fb6 100644
--- a/docs/qmp-commands.txt
+++ b/docs/qmp-commands.txt
@@ -3800,3 +3800,39 @@ Example for pc machine type started with
             "props": {"core-id": 0, "socket-id": 0, "thread-id": 0}
          }
        ]}
+
+EQMP
+
+    {
+        .name       = "query-nvdimms",
+        .args_type  = "",
+        .mhandler.cmd_new = qmp_marshal_query_nvdimms,
+    },
+
+SQMP
+Show plugged NVDIMM devices
+---------------------------
+
+Arguments: None.
+
+Example for pc machine type started with
+-object memory-backend-file,id=mem1,mem-path=/path/to/nvm1,size=4G
+-device nvdimm,id=nvdimm1,memdev=mem1
+-object memory-backend-file,id=mem2,mem-path=/path/to/nvm2,size=8G
+-device nvdimm,id=nvdimm2,memdev=mem2:
+
+-> { "execute": "query-nvdimms" }
+<- { "returns": [
+      {
+         "mem-path": "/path/to/nvm1",
+	 "slot": 0,
+	 "spa": 17179869184,
+	 "length": 4294967296
+      },
+      {
+         "mem-path": "/path/to/nvm2",
+	 "slot": 1,
+	 "spa": 21474836480,
+	 "length": 8589934592
+      }
+   ]}
diff --git a/hw/acpi/nvdimm.c b/hw/acpi/nvdimm.c
index 4cfb94d..eedc128 100644
--- a/hw/acpi/nvdimm.c
+++ b/hw/acpi/nvdimm.c
@@ -57,7 +57,7 @@ static int nvdimm_plugged_device_list(Object *obj, void *opaque)
  * Note: it is the caller's responsibility to free the list to avoid
  * memory leak.
  */
-static GSList *nvdimm_get_plugged_device_list(void)
+GSList *nvdimm_get_plugged_device_list(void)
 {
     GSList *list = NULL;
 
diff --git a/hw/mem/nvdimm.c b/hw/mem/nvdimm.c
index d25993b..99d0cc9 100644
--- a/hw/mem/nvdimm.c
+++ b/hw/mem/nvdimm.c
@@ -26,6 +26,7 @@
 #include "qapi/error.h"
 #include "qapi/visitor.h"
 #include "hw/mem/nvdimm.h"
+#include "qmp-commands.h"
 
 static void nvdimm_get_label_size(Object *obj, Visitor *v, const char *name,
                                   void *opaque, Error **errp)
@@ -180,3 +181,37 @@ static void nvdimm_register_types(void)
 }
 
 type_init(nvdimm_register_types)
+
+NvdimmInfoList *qmp_query_nvdimms(Error **errp)
+{
+    NvdimmInfoList *info_list = NULL;
+    NvdimmInfoList *info;
+    GSList *device_list = nvdimm_get_plugged_device_list();
+
+    while (device_list) {
+        DeviceState *dev = device_list->data;
+        PCDIMMDevice *parent = PC_DIMM(OBJECT(dev));
+        const char *mem_path;
+
+        info = g_new0(NvdimmInfoList, 1);
+        info->value = g_new0(NvdimmInfo, 1);
+
+        mem_path = object_property_get_str(OBJECT(parent->hostmem),
+                                           "mem-path", NULL);
+        info->value->mem_path = mem_path ? strdup(mem_path) : NULL;
+
+        info->value->slot = object_property_get_int(OBJECT(dev),
+                                                    PC_DIMM_SLOT_PROP, NULL);
+        info->value->spa = object_property_get_int(OBJECT(dev),
+                                                   PC_DIMM_ADDR_PROP, NULL);
+        info->value->length = object_property_get_int(OBJECT(dev),
+                                                      PC_DIMM_SIZE_PROP, NULL);
+
+        info->next = info_list;
+        info_list = info;
+        device_list = device_list->next;
+    }
+
+    g_slist_free(device_list);
+    return info_list;
+}
diff --git a/include/hw/mem/nvdimm.h b/include/hw/mem/nvdimm.h
index 1cfe9e0..6be269e 100644
--- a/include/hw/mem/nvdimm.h
+++ b/include/hw/mem/nvdimm.h
@@ -113,4 +113,14 @@ 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);
+
+/*
+ * Inquire plugged NVDIMM devices and link them into the list which is
+ * returned to the caller.
+ *
+ * Note: it is the caller's responsibility to free the list to avoid
+ * memory leak.
+ */
+GSList *nvdimm_get_plugged_device_list(void);
+
 #endif
diff --git a/qapi-schema.json b/qapi-schema.json
index c3dcf11..6246255 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -4646,3 +4646,32 @@
 # Since: 2.7
 ##
 { 'command': 'query-hotpluggable-cpus', 'returns': ['HotpluggableCPU'] }
+
+##
+# @NvdimmInfo
+#
+# Information about an NVDIMM device.
+#
+# @mem-path: the backend file of the NVDIMM device
+#
+# @slot: the slot index of the NVDIMM device
+#
+# @spa: the 64-bit SPA base address of the NVDIMM device
+#
+# @length: the 64-bit size in bytes of the NVDIMM device
+#
+# Since 2.8
+##
+{ 'struct': 'NvdimmInfo',
+  'data': {'mem-path' : 'str', 'slot': 'int', 'spa': 'int', 'length': 'int'} }
+
+##
+# @query-nvdimms:
+#
+# Returns information about each NVDIMM device
+#
+# Returns: a list of @NvdimmInfo for each device
+#
+# Since: 2.8
+##
+{ 'command': 'query-nvdimms', 'returns': ['NvdimmInfo'] }
-- 
2.10.1


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