[v7,06/14] cxl: Setup exclusive CXL features that are reserved for the kernel

Commit Message

Dave Jiang Feb. 20, 2025, 7:42 p.m. UTC

Certain features will be exclusively used by components such as in
kernel RAS driver. Setup an exclusion list that can be used to detect
if a feature is exclusive to the kernel.

Reviewed-by: Jonathan Cameron <[e-mail]>
Reviewed-by: Dan Williams <[e-mail]>
Reviewed-by: Li Ming <[e-mail]>
Tested-by: Shiju Jose <[e-mail]>
Signed-off-by: Dave Jiang <[e-mail]>
---
 drivers/cxl/core/features.c | 28 ++++++++++++++++++++++++++++
 include/cxl/features.h      | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 62 insertions(+)

Patch

diff --git a/drivers/cxl/core/features.c b/drivers/cxl/core/features.c
index 17a82734a340..048ba4fc3538 100644
--- a/drivers/cxl/core/features.c
+++ b/drivers/cxl/core/features.c
@@ -7,6 +7,28 @@ 
 #include "core.h"
 #include "cxlmem.h"
 
+/* All the features below are exclusive to the kernel */
+static const uuid_t cxl_exclusive_feats[] = {
+	CXL_FEAT_PATROL_SCRUB_UUID,
+	CXL_FEAT_ECS_UUID,
+	CXL_FEAT_SPPR_UUID,
+	CXL_FEAT_HPPR_UUID,
+	CXL_FEAT_CACHELINE_SPARING_UUID,
+	CXL_FEAT_ROW_SPARING_UUID,
+	CXL_FEAT_BANK_SPARING_UUID,
+	CXL_FEAT_RANK_SPARING_UUID,
+};
+
+static bool is_cxl_feature_exclusive(struct cxl_feat_entry *entry)
+{
+	for (int i = 0; i < ARRAY_SIZE(cxl_exclusive_feats); i++) {
+		if (uuid_equal(&entry->uuid, &cxl_exclusive_feats[i]))
+			return true;
+	}
+
+	return false;
+}
+
 inline struct cxl_features_state *to_cxlfs(struct cxl_dev_state *cxlds)
 {
 	return cxlds->cxlfs;
@@ -47,6 +69,7 @@  get_supported_features(struct cxl_features_state *cxlfs)
 	struct cxl_mbox_get_sup_feats_in mbox_in;
 	struct cxl_feat_entry *entry;
 	struct cxl_mbox_cmd mbox_cmd;
+	int user_feats = 0;
 	int count;
 
 	count = cxl_get_supported_features_count(cxl_mbox);
@@ -121,6 +144,10 @@  get_supported_features(struct cxl_features_state *cxlfs)
 			return NULL;
 
 		memcpy(entry, mbox_out->ents, retrieved);
+		for (int i = 0; i < num_entries; i++) {
+			if (!is_cxl_feature_exclusive(entry + i))
+				user_feats++;
+		}
 		entry += num_entries;
 		/*
 		 * If the number of output entries is less than expected, add the
@@ -131,6 +158,7 @@  get_supported_features(struct cxl_features_state *cxlfs)
 	} while (remain_feats);
 
 	entries->num_features = count;
+	entries->num_user_features = user_feats;
 
 	return no_free_ptr(entries);
 }
diff --git a/include/cxl/features.h b/include/cxl/features.h
index ae56ef7ec9ab..d2cde46b0fec 100644
--- a/include/cxl/features.h
+++ b/include/cxl/features.h
@@ -5,6 +5,39 @@ 
 
 #include <linux/uuid.h>
 
+/* Feature UUIDs used by the kernel */
+#define CXL_FEAT_PATROL_SCRUB_UUID						\
+	UUID_INIT(0x96dad7d6, 0xfde8, 0x482b, 0xa7, 0x33, 0x75, 0x77, 0x4e,	\
+		  0x06, 0xdb, 0x8a)
+
+#define CXL_FEAT_ECS_UUID							\
+	UUID_INIT(0xe5b13f22, 0x2328, 0x4a14, 0xb8, 0xba, 0xb9, 0x69, 0x1e,	\
+		  0x89, 0x33, 0x86)
+
+#define CXL_FEAT_SPPR_UUID							\
+	UUID_INIT(0x892ba475, 0xfad8, 0x474e, 0x9d, 0x3e, 0x69, 0x2c, 0x91,	\
+		  0x75, 0x68, 0xbb)
+
+#define CXL_FEAT_HPPR_UUID							\
+	UUID_INIT(0x80ea4521, 0x786f, 0x4127, 0xaf, 0xb1, 0xec, 0x74, 0x59,	\
+		  0xfb, 0x0e, 0x24)
+
+#define CXL_FEAT_CACHELINE_SPARING_UUID						\
+	UUID_INIT(0x96C33386, 0x91dd, 0x44c7, 0x9e, 0xcb, 0xfd, 0xaf, 0x65,	\
+		  0x03, 0xba, 0xc4)
+
+#define CXL_FEAT_ROW_SPARING_UUID						\
+	UUID_INIT(0x450ebf67, 0xb135, 0x4f97, 0xa4, 0x98, 0xc2, 0xd5, 0x7f,	\
+		  0x27, 0x9b, 0xed)
+
+#define CXL_FEAT_BANK_SPARING_UUID						\
+	UUID_INIT(0x78b79636, 0x90ac, 0x4b64, 0xa4, 0xef, 0xfa, 0xac, 0x5d,	\
+		  0x18, 0xa8, 0x63)
+
+#define CXL_FEAT_RANK_SPARING_UUID						\
+	UUID_INIT(0x34dbaff5, 0x0552, 0x4281, 0x8f, 0x76, 0xda, 0x0b, 0x5e,	\
+		  0x7a, 0x76, 0xa7)
+
 /* Feature commands capability supported by a device */
 enum cxl_features_capability {
 	CXL_FEATURES_NONE = 0,
@@ -134,6 +167,7 @@  struct cxl_features_state {
 	struct cxl_dev_state *cxlds;
 	struct cxl_feat_entries {
 		int num_features;
+		int num_user_features;
 		struct cxl_feat_entry ent[] __counted_by(num_features);
 	} *entries;
 };