intelrdt: honor default closID

implement the change specified here:

opencontainers/runtime-spec#1289

Signed-off-by: Giuseppe Scrivano <[email protected]>

Author: giuseppe

src/libcrun/intelrdt.c

@@ -167,13 +167,19 @@ compare_rdt_configurations (const char *a, const char *b)
   return 0;
 }
 
+static bool
+is_default_clos (const char *name)
+{
+  return strcmp (name, "/") == 0;
+}
+
 static int
 get_resctrl_path (char **path, const char *file, const char *name, libcrun_error_t *err)
 {
-  if (file)
-    return append_paths (path, err, INTEL_RDT_MOUNT_POINT, name, file, NULL);
-  else
-    return append_paths (path, err, INTEL_RDT_MOUNT_POINT, name, NULL);
+  if (is_default_clos (name))
+    return append_paths (path, err, INTEL_RDT_MOUNT_POINT, file, NULL);
+
+  return append_paths (path, err, INTEL_RDT_MOUNT_POINT, name, file, NULL);
 }
 
 static int
@@ -282,7 +288,7 @@ resctl_create (const char *name, bool explicit_clos_id, bool *created, const cha
      must exist.  */
   if (explicit_clos_id && l3_cache_schema == NULL && mem_bw_schema == NULL)
     {
-      if (exist)
+      if (exist || is_default_clos (name))
         return 0;
 
       return crun_make_error (err, 0, "the resctl group `%s` does not exist", name);
@@ -292,6 +298,9 @@ resctl_create (const char *name, bool explicit_clos_id, bool *created, const cha
   if (exist && (l3_cache_schema != NULL || mem_bw_schema != NULL))
     return validate_rdt_configuration (name, l3_cache_schema, mem_bw_schema, err);
 
+  if (is_default_clos (name))
+    return 0;
+
   /* At this point, assume it was created.  */
   ret = crun_ensure_directory (path, 0755, true, err);
   if (UNLIKELY (ret < 0))
@@ -357,6 +366,9 @@ resctl_destroy (const char *name, libcrun_error_t *err)
   cleanup_free char *path = NULL;
   int ret;
 
+  if (is_default_clos (name))
+    return 0;
+
   ret = get_resctrl_path (&path, NULL, name, err);
   if (UNLIKELY (ret < 0))
     return ret;