linux-kernel - [RFC PATCH 10/20] nvdimm/region_label: Preserve cxl region information from region label

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Message-Id: <680779399.221750165205474.JavaMail.epsvc@epcpadp1new>
Date: Tue, 17 Jun 2025 18:09:34 +0530
From: Neeraj Kumar <s.neeraj@...sung.com>
To: dan.j.williams@...el.com, dave@...olabs.net,
	jonathan.cameron@...wei.com, dave.jiang@...el.com,
	alison.schofield@...el.com, vishal.l.verma@...el.com, ira.weiny@...el.com
Cc: a.manzanares@...sung.com, nifan.cxl@...il.com, anisa.su@...sung.com,
	vishak.g@...sung.com, krish.reddy@...sung.com, arun.george@...sung.com,
	alok.rathore@...sung.com, s.neeraj@...sung.com, neeraj.kernel@...il.com,
	linux-kernel@...r.kernel.org, linux-cxl@...r.kernel.org,
	nvdimm@...ts.linux.dev, gost.dev@...sung.com, cpgs@...sung.com
Subject: [RFC PATCH 10/20] nvdimm/region_label: Preserve cxl region
 information from region label

Preserve region information from region label during nvdimm_probe. This
preserved region information is used for creating cxl region to achieve
region persistency across reboot.

Signed-off-by: Neeraj Kumar <s.neeraj@...sung.com>
---
 drivers/nvdimm/dimm.c     |  4 ++++
 drivers/nvdimm/label.c    | 41 +++++++++++++++++++++++++++++++++++++++
 drivers/nvdimm/nd-core.h  |  2 ++
 drivers/nvdimm/nd.h       |  1 +
 include/linux/libnvdimm.h | 14 +++++++++++++
 5 files changed, 62 insertions(+)

diff --git a/drivers/nvdimm/dimm.c b/drivers/nvdimm/dimm.c
index 8753b5cd91cc..da4f37f0ae3b 100644
--- a/drivers/nvdimm/dimm.c
+++ b/drivers/nvdimm/dimm.c
@@ -107,6 +107,10 @@ static int nvdimm_probe(struct device *dev)
 	if (rc)
 		goto err;
 
+	/* Preserve cxl region info if available */
+	if (ndd->cxl)
+		nvdimm_cxl_region_preserve(ndd);
+
 	return 0;
 
  err:
diff --git a/drivers/nvdimm/label.c b/drivers/nvdimm/label.c
index 3a870798a90c..6a94175e6bb6 100644
--- a/drivers/nvdimm/label.c
+++ b/drivers/nvdimm/label.c
@@ -471,6 +471,47 @@ int nd_label_reserve_dpa(struct nvdimm_drvdata *ndd)
 	return 0;
 }
 
+int nvdimm_cxl_region_preserve(struct nvdimm_drvdata *ndd)
+{
+	struct nvdimm *nvdimm = to_nvdimm(ndd->dev);
+	struct cxl_pmem_region_params *params = &nvdimm->cxl_region_params;
+	struct nd_namespace_index *nsindex;
+	unsigned long *free;
+	u32 nslot, slot;
+
+	if (!preamble_current(ndd, &nsindex, &free, &nslot))
+		return 0; /* no label, nothing to preserve */
+
+	for_each_clear_bit_le(slot, free, nslot) {
+		struct nd_lsa_label *nd_label;
+		struct cxl_region_label *rg_label;
+		uuid_t rg_type, region_type;
+
+		nd_label = to_label(ndd, slot);
+		rg_label = &nd_label->rg_label;
+		uuid_parse(CXL_REGION_UUID, &region_type);
+		import_uuid(&rg_type, nd_label->rg_label.type);
+
+		/* REVISIT: Currently preserving only one region */
+		if (uuid_equal(&region_type, &rg_type)) {
+			nvdimm->is_region_label = true;
+			import_uuid(&params->uuid, rg_label->uuid);
+			params->flags = __le32_to_cpu(rg_label->flags);
+			params->nlabel = __le16_to_cpu(rg_label->nlabel);
+			params->position = __le16_to_cpu(rg_label->position);
+			params->dpa = __le64_to_cpu(rg_label->dpa);
+			params->rawsize = __le64_to_cpu(rg_label->rawsize);
+			params->hpa = __le64_to_cpu(rg_label->hpa);
+			params->slot = __le32_to_cpu(rg_label->slot);
+			params->ig = __le32_to_cpu(rg_label->ig);
+			params->align = __le32_to_cpu(rg_label->align);
+			break;
+		}
+	}
+
+	return 0;
+}
+
 int nd_label_data_init(struct nvdimm_drvdata *ndd)
 {
 	size_t config_size, read_size, max_xfer, offset;
diff --git a/drivers/nvdimm/nd-core.h b/drivers/nvdimm/nd-core.h
index 86976a9e8a15..71eabf2db389 100644
--- a/drivers/nvdimm/nd-core.h
+++ b/drivers/nvdimm/nd-core.h
@@ -46,6 +46,8 @@ struct nvdimm {
 	} sec;
 	struct delayed_work dwork;
 	const struct nvdimm_fw_ops *fw_ops;
+	bool is_region_label;
+	struct cxl_pmem_region_params cxl_region_params;
 };
 
 static inline unsigned long nvdimm_security_flags(
diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index ca8256b31472..33a87924dfee 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -600,6 +600,7 @@ void nvdimm_set_locked(struct device *dev);
 void nvdimm_clear_locked(struct device *dev);
 int nvdimm_security_setup_events(struct device *dev);
 bool nvdimm_check_cxl_label_format(struct device *dev);
+int nvdimm_cxl_region_preserve(struct nvdimm_drvdata *ndd);
 #if IS_ENABLED(CONFIG_NVDIMM_KEYS)
 int nvdimm_security_unlock(struct device *dev);
 #else
diff --git a/include/linux/libnvdimm.h b/include/linux/libnvdimm.h
index b2e16914ab52..cdabb43a8a7f 100644
--- a/include/linux/libnvdimm.h
+++ b/include/linux/libnvdimm.h
@@ -106,6 +106,20 @@ struct nd_cmd_desc {
 	int out_sizes[ND_CMD_MAX_ELEM];
 };
 
+struct cxl_pmem_region_params {
+	uuid_t uuid;
+	u32 flags;
+	u16 nlabel;
+	u16 position;
+	u64 dpa;
+	u64 rawsize;
+	u64 hpa;
+	u32 slot;
+	u32 ig;
+	u32 align;
+	int nr_targets;
+};
+
 struct nd_interleave_set {
 	/* v1.1 definition of the interleave-set-cookie algorithm */
 	u64 cookie1;
-- 
2.34.1