[PATCH v1 08/14] cxl/extent: Validate DC extent partition

[Anisa Su]

From: Ira Weiny <iweiny@xxxxxxxxxx>

Extend cxl_validate_extent() — the per-extent check of the add pipeline
to check partition membership.

Resolves an extent's DPA to its containing DC partition.  Sharability is
a property of the partition (part->shareable), taken from its CDAT DSMAS
entry.

An extent from a sharable partition must carry a non-null tag, since hosts
sharing the allocation key on that tag.  A null tag there is a device
firmware bug; reject the extent.

A non-sharable extent must carry 0 in shared_extn_seq (CXL r4.0 Table
8-230); a non-zero value is rejected the same way.  The dense 0..n-1
check for sharable groups follows in the next commit, once the whole
tag group is collected.

Based on patches by John Groves.

Signed-off-by: Ira Weiny <iweiny@xxxxxxxxxx>
Co-developed-by: John Groves <John@xxxxxxxxxx>
Signed-off-by: John Groves <John@xxxxxxxxxx>
Co-developed-by: Anisa Su <anisa.su@xxxxxxxxxxx>
Signed-off-by: Anisa Su <anisa.su@xxxxxxxxxxx>
Tested-by: Wonjae Lee <wj28.lee@xxxxxxxxxxx>
Tested-by: Junhee Park <jh9934.park@xxxxxxxxxxx>
Tested-by: Heesoo Kim <habil.kim@xxxxxxxxxxx>
---
 drivers/cxl/core/core.h   | 12 +++++++
 drivers/cxl/core/extent.c | 70 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 82 insertions(+)

diff --git a/drivers/cxl/core/core.h b/drivers/cxl/core/core.h
index 759f2c47d765..528eec2a1cc3 100644
--- a/drivers/cxl/core/core.h
+++ b/drivers/cxl/core/core.h
@@ -83,6 +83,10 @@ int online_tag_group(struct cxl_dc_tag_group *group);
 bool rm_tag_group(struct cxl_dc_tag_group *group);
 void discard_tag_group(struct cxl_dc_tag_group *group);
 int cxl_dax_untagged_add(struct cxl_dax_region *cxlr_dax);
+const struct cxl_dpa_partition *
+cxl_extent_dc_partition(struct cxl_memdev_state *mds,
+			struct cxl_extent *extent,
+			struct range *ext_range);
 #else
 static inline u64 cxl_dpa_to_hpa(struct cxl_region *cxlr,
 				 const struct cxl_memdev *cxlmd, u64 dpa)
@@ -144,6 +148,14 @@ static inline void kill_regions(struct cxl_root_decoder *cxlrd) { };
 #define SET_CXL_REGION_ATTR(x)
 #define CXL_PMEM_REGION_TYPE(x) NULL
 #define CXL_DAX_REGION_TYPE(x) NULL
+
+static inline const struct cxl_dpa_partition *
+cxl_extent_dc_partition(struct cxl_memdev_state *mds,
+			struct cxl_extent *extent,
+			struct range *ext_range)
+{
+	return NULL;
+}
 #endif
 
 struct cxl_send_command;
diff --git a/drivers/cxl/core/extent.c b/drivers/cxl/core/extent.c
index 8afb18e7ae5a..334a97ab583d 100644
--- a/drivers/cxl/core/extent.c
+++ b/drivers/cxl/core/extent.c
@@ -115,6 +115,51 @@ alloc_tag_group(struct cxl_dax_region *cxlr_dax, uuid_t *uuid)
 	return no_free_ptr(group);
 }
 
+/*
+ * Find the DC (Dynamic Capacity) partition that fully contains @ext_range,
+ * or NULL if the extent falls outside every DC partition on this memdev.
+ * The returned pointer is owned by mds->cxlds.part[] and lives for the
+ * lifetime of the memdev.
+ */
+const struct cxl_dpa_partition *
+cxl_extent_dc_partition(struct cxl_memdev_state *mds,
+			struct cxl_extent *extent,
+			struct range *ext_range)
+{
+	struct cxl_dev_state *cxlds = &mds->cxlds;
+	struct device *dev = mds->cxlds.dev;
+
+	/*
+	 * A device-side error could cause end < start, which range_contains()
+	 * would treat as contained in any partition.
+	 */
+	if (ext_range->end < ext_range->start) {
+		dev_err_ratelimited(dev,
+				    "DC extent DPA %pra (%pU) has invalid length (firmware bug)\n",
+				    ext_range, extent->uuid);
+		return NULL;
+	}
+
+	for (int i = 0; i < cxlds->nr_partitions; i++) {
+		struct cxl_dpa_partition *part = &cxlds->part[i];
+		struct range partition_range = {
+			.start = part->res.start,
+			.end = part->res.end,
+		};
+
+		if (part->mode != CXL_PARTMODE_DYNAMIC_RAM)
+			continue;
+
+		if (range_contains(&partition_range, ext_range))
+			return part;
+	}
+
+	dev_err_ratelimited(dev,
+			    "DC extent DPA %pra (%pU) is not in a valid DC partition\n",
+			    ext_range, extent->uuid);
+	return NULL;
+}
+
 /*
  * Stage 1 of the add pipeline: pure, no allocation.  Resolve the extent
  * to its region/endpoint decoder and ext_range, and verify the range
@@ -133,6 +178,8 @@ static int cxl_validate_extent(struct cxl_memdev_state *mds,
 {
 	u64 start_dpa = le64_to_cpu(extent->start_dpa);
 	struct cxl_memdev *cxlmd = mds->cxlds.cxlmd;
+	struct device *dev = mds->cxlds.dev;
+	const struct cxl_dpa_partition *part;
 	struct cxl_endpoint_decoder *cxled;
 	struct cxl_region *cxlr;
 	struct range ext_range = (struct range) {
@@ -140,6 +187,29 @@ static int cxl_validate_extent(struct cxl_memdev_state *mds,
 		.end = start_dpa + le64_to_cpu(extent->length) - 1,
 	};
 	struct range ed_range;
+	uuid_t uuid;
+
+	import_uuid(&uuid, extent->uuid);
+
+	part = cxl_extent_dc_partition(mds, extent, &ext_range);
+	if (!part)
+		return -ENXIO;
+	dev_dbg(dev, "DC extent DPA %pra (DCR:%pR)(%pU)\n", &ext_range,
+		&part->res, &uuid);
+
+	if (part->shareable) {
+		if (uuid_is_null(&uuid)) {
+			dev_err_ratelimited(dev,
+					    "DC extent DPA %pra: sharable-partition extent has null tag (firmware bug)\n",
+					    &ext_range);
+			return -ENXIO;
+		}
+	} else if (le16_to_cpu(extent->shared_extn_seq)) {
+		dev_err_ratelimited(dev,
+				    "DC extent DPA %pra (%pU): non-sharable partition but shared_extn_seq=%u (firmware bug)\n",
+				    &ext_range, &uuid, le16_to_cpu(extent->shared_extn_seq));
+		return -ENXIO;
+	}
 
 	cxlr = cxl_dpa_to_region(cxlmd, start_dpa, &cxled);
 	if (!cxlr || !cxlr->cxlr_dax)
-- 
2.43.0