diff --git a/docs/misra/rules.rst b/docs/misra/rules.rst
index 6efe66195d..aa65eb4dd0 100644
--- a/docs/misra/rules.rst
+++ b/docs/misra/rules.rst
@@ -341,6 +341,9 @@ maintainers if you want to suggest a change.
            compilers' extensions)
          - Implicit conversions to boolean for conditionals (?: if while
            for) and logical operators (! || &&)
+         - The essential type model allows the constants defined by anonymous
+           enums (e.g., enum { A, B, C }) to be used as operands to arithmetic
+           operators, as they have a signed essential type.
 
    * - `Rule 10.2 <https://gitlab.com/MISRA/MISRA-C/MISRA-C-2012/Example-Suite/-/blob/master/R_10_02.c>`_
      - Required
diff --git a/xen/include/xen/perfc.h b/xen/include/xen/perfc.h
index 7c5ce537bd..96022c0748 100644
--- a/xen/include/xen/perfc.h
+++ b/xen/include/xen/perfc.h
@@ -39,7 +39,7 @@
 #define PERFSTATUS       PERFCOUNTER
 #define PERFSTATUS_ARRAY PERFCOUNTER_ARRAY
 
-enum perfcounter {
+enum {
 #include <xen/perfc_defn.h>
 	NUM_PERFCOUNTERS
 };