[v18,14/19] cxl: Setup exclusive CXL features that are reserved for the kernel

Commit Message

Shiju Jose Jan. 6, 2025, 12:10 p.m. UTC

From: Dave Jiang <[e-mail]>

Certain features will be exclusively used by components such as in
kernel RAS driver. Setup an exclusion list that can be later filtered
out before exposing to user space.

Signed-off-by: Dave Jiang <[e-mail]>
---
 drivers/cxl/core/features.c | 22 ++++++++++++++++++++++
 drivers/cxl/features.c      |  6 +++++-
 include/cxl/features.h      | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 61 insertions(+), 1 deletion(-)

Patch

diff --git a/drivers/cxl/core/features.c b/drivers/cxl/core/features.c
index 932e82b52f90..c836b3a64561 100644
--- a/drivers/cxl/core/features.c
+++ b/drivers/cxl/core/features.c
@@ -6,6 +6,17 @@ 
 #include "core.h"
 #include "cxlmem.h"
 
+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,
+};
+
 #define CXL_FEATURE_MAX_DEVS 65536
 static DEFINE_IDA(cxl_features_ida);
 
@@ -263,3 +274,14 @@  int cxl_set_feature(struct cxl_features *features,
 	} while (true);
 }
 EXPORT_SYMBOL_NS_GPL(cxl_set_feature, "CXL");
+
+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;
+}
+EXPORT_SYMBOL_NS_GPL(is_cxl_feature_exclusive, "CXL");
diff --git a/drivers/cxl/features.c b/drivers/cxl/features.c
index 2faa9e03a840..3388bce5943a 100644
--- a/drivers/cxl/features.c
+++ b/drivers/cxl/features.c
@@ -47,6 +47,7 @@  static int cxl_get_supported_features(struct cxl_features_state *cfs)
 	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;
 
 	/* Get supported features is optional, need to check */
@@ -127,6 +128,8 @@  static int cxl_get_supported_features(struct cxl_features_state *cfs)
 			return -ENXIO;
 
 		memcpy(entry, mbox_out->ents, retrieved);
+		if (!is_cxl_feature_exclusive(entry))
+			user_feats++;
 		entry++;
 		/*
 		 * If the number of output entries is less than expected, add the
@@ -138,6 +141,7 @@  static int cxl_get_supported_features(struct cxl_features_state *cfs)
 
 	cfs->num_features = count;
 	cfs->entries = no_free_ptr(entries);
+	cfs->num_user_features = user_feats;
 	return devm_add_action_or_reset(&cfs->features->dev,
 					cxl_free_feature_entries, cfs->entries);
 }
@@ -177,7 +181,7 @@  static ssize_t features_show(struct device *dev, struct device_attribute *attr,
 	if (!cfs)
 		return -ENOENT;
 
-	return sysfs_emit(buf, "%d\n", cfs->num_features);
+	return sysfs_emit(buf, "%d\n", cfs->num_user_features);
 }
 
 static DEVICE_ATTR_RO(features);
diff --git a/include/cxl/features.h b/include/cxl/features.h
index 41d3602b186c..adff3496b4be 100644
--- a/include/cxl/features.h
+++ b/include/cxl/features.h
@@ -5,6 +5,38 @@ 
 
 #include <linux/uuid.h>
 
+#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)
+
 struct cxl_mailbox;
 
 enum feature_cmds {
@@ -50,6 +82,7 @@  struct cxl_mbox_get_sup_feats_out {
 struct cxl_features_state {
 	struct cxl_features *features;
 	int num_features;
+	int num_user_features;
 	struct cxl_feat_entry *entries;
 };
 
@@ -117,5 +150,6 @@  size_t cxl_get_feature(struct cxl_features *features, const uuid_t feat_uuid,
 int cxl_set_feature(struct cxl_features *features, const uuid_t feat_uuid,
 		    u8 feat_version, void *feat_data, size_t feat_data_size,
 		    u32 feat_flag, u16 offset, u16 *return_code);
+bool is_cxl_feature_exclusive(struct cxl_feat_entry *entry);
 
 #endif