[PATCH v2 07/16] cxl: Setup exclusive CXL features that are reserved for the kernel

[Dave Jiang <dave.jiang@intel.com>]

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.

Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
---
 drivers/cxl/core/features.c | 29 +++++++++++++++++++++++++++++
 drivers/cxl/features.c      |  4 ++++
 drivers/cxl/features.h      |  3 +++
 include/cxl/features.h      | 35 +++++++++++++++++++++++++++++++++++
 4 files changed, 71 insertions(+)

diff --git a/drivers/cxl/core/features.c b/drivers/cxl/core/features.c
index 7dd3b64b6976..132f93050d1c 100644
--- a/drivers/cxl/core/features.c
+++ b/drivers/cxl/core/features.c
@@ -8,6 +8,35 @@
 #include "cxlmem.h"
 #include "features.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,
+};
+
+/**
+ * is_cxl_feature_exclusive() - Check if a CXL feature is exclusive to kernel
+ * @entry: cxl feature entry
+ *
+ * Return true if feature is exclusive to kernel, otherwise false
+ */
+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");
+
 size_t cxl_get_feature(struct cxl_mailbox *cxl_mbox, const uuid_t *feat_uuid,
 		       enum cxl_get_feat_selection selection,
 		       void *feat_out, size_t feat_out_size, u16 offset,
diff --git a/drivers/cxl/features.c b/drivers/cxl/features.c
index be6c19b01b90..82598a409acc 100644
--- a/drivers/cxl/features.c
+++ b/drivers/cxl/features.c
@@ -46,6 +46,7 @@ static int get_supported_features(struct cxl_memdev *cxlmd,
 	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;
 
 	if (cxlfs->cap < CXL_FEATURES_RO)
@@ -125,6 +126,8 @@ static int get_supported_features(struct cxl_memdev *cxlmd,
 			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
@@ -135,6 +138,7 @@ static int get_supported_features(struct cxl_memdev *cxlmd,
 	} while (remain_feats);
 
 	cxlfs->num_features = count;
+	cxlfs->num_user_features = user_feats;
 	cxlfs->entries = no_free_ptr(entries);
 	return devm_add_action_or_reset(&cxlmd->dev, cxl_free_feature_entries,
 					cxlfs->entries);
diff --git a/drivers/cxl/features.h b/drivers/cxl/features.h
index 0cc6d9e6c441..8706f944b476 100644
--- a/drivers/cxl/features.h
+++ b/drivers/cxl/features.h
@@ -3,6 +3,9 @@
 #ifndef __CXL_FEATURES_LOCAL__
 #define __CXL_FEATURES_LOCAL__
 
+struct cxl_feat_entry;
+
 int devm_cxl_add_features(struct cxl_memdev *cxlmd);
+bool is_cxl_feature_exclusive(struct cxl_feat_entry *entry);
 
 #endif
diff --git a/include/cxl/features.h b/include/cxl/features.h
index d10ef2b54f45..7ae84696d6dd 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)
+
 struct cxl_mailbox;
 
 /* Index IDs for CXL mailbox Feature commands */
@@ -27,12 +60,14 @@ enum cxl_features_capability {
  * @cxlmd: Pointer to cxl mem device
  * @cap: Feature commands capability
  * @num_features: total Features supported by the device
+ * @num_user_features: total Features not kernel exclusive
  * @entries: Feature detail entries fetched from the device
  */
 struct cxl_features_state {
 	struct cxl_memdev *cxlmd;
 	enum cxl_features_capability cap;
 	int num_features;
+	int num_user_features;
 	struct cxl_feat_entry *entries;
 };
 
-- 
2.48.1