cxl: add dimm_id support for __nvdimm_create()

Set the cxlds->serial as the dimm_id to be fed to __nvdimm_create(). The
security code uses that as the key description for the security key of the
memory device. The nvdimm unlock code cannot find the respective key
without the dimm_id.
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/166863357043.80269.4337575149671383294.stgit@djiang5-desk3.ch.intel.com
Link: https://lore.kernel.org/r/166983620459.2734609.10175456773200251184.stgit@djiang5-desk3.ch.intel.com
Link: https://lore.kernel.org/r/166993219918.1995348.10786511454826454601.stgit@dwillia2-xfh.jf.intel.comSigned-off-by: Dan Williams <dan.j.williams@intel.com>

drivers/cxl/core/pmem.c

@@ -238,6 +238,13 @@ static struct cxl_nvdimm *cxl_nvdimm_alloc(struct cxl_memdev *cxlmd)
 	dev->parent = &cxlmd->dev;
 	dev->bus = &cxl_bus_type;
 	dev->type = &cxl_nvdimm_type;
+	/*
+	 * A "%llx" string is 17-bytes vs dimm_id that is max
+	 * NVDIMM_KEY_DESC_LEN
+	 */
+	BUILD_BUG_ON(sizeof(cxl_nvd->dev_id) < 17 ||
+		     sizeof(cxl_nvd->dev_id) > NVDIMM_KEY_DESC_LEN);
+	sprintf(cxl_nvd->dev_id, "%llx", cxlmd->cxlds->serial);
 
 	return cxl_nvd;
 }

drivers/cxl/cxl.h

@@ -420,11 +420,14 @@ struct cxl_nvdimm_bridge {
 	enum cxl_nvdimm_brige_state state;
 };
 
+#define CXL_DEV_ID_LEN 19
+
 struct cxl_nvdimm {
 	struct device dev;
 	struct cxl_memdev *cxlmd;
 	struct cxl_nvdimm_bridge *bridge;
 	struct xarray pmem_regions;
+	u8 dev_id[CXL_DEV_ID_LEN]; /* for nvdimm, string of 'serial' */
 };
 
 struct cxl_pmem_region_mapping {

drivers/cxl/pmem.c

@@ -117,7 +117,8 @@ static int cxl_nvdimm_probe(struct device *dev)
 	set_bit(ND_CMD_SET_CONFIG_DATA, &cmd_mask);
 	nvdimm = __nvdimm_create(cxl_nvb->nvdimm_bus, cxl_nvd,
 				 cxl_dimm_attribute_groups, flags,
-				 cmd_mask, 0, NULL, NULL, cxl_security_ops, NULL);
+				 cmd_mask, 0, NULL, cxl_nvd->dev_id,
+				 cxl_security_ops, NULL);
 	if (!nvdimm) {
 		rc = -ENOMEM;
 		goto out;