cxl: Setup exclusive CXL features that are reserved for the kernel

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 <Jonathan.Cameron@huawei.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Li Ming <ming.li@zohomail.com>
Tested-by: Shiju Jose <shiju.jose@huawei.com>
Link: https://patch.msgid.link/20250220194438.2281088-7-dave.jiang@intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>

diff --git a/drivers/cxl/core/features.c b/drivers/cxl/core/features.c
index 17a82734a34067acd43226ebf8d6ecd16aa52461..048ba4fc3538e7dc5c08e59f5d71384dd931caa0 100644 (file)
--- 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 ae56ef7ec9aba62b2f61fc3e4fc4563f14e1182b..d2cde46b0fec8aebd2f1d88aeb3670b8abd845fc 100644 (file)
--- 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;
 };