diff --git a/include/exec/memattrs.h b/include/exec/memattrs.h
index 9fb98bc1ef..d04170aa27 100644
--- a/include/exec/memattrs.h
+++ b/include/exec/memattrs.h
@@ -29,10 +29,17 @@ typedef struct MemTxAttrs {
      * "didn't specify" if necessary.
      */
     unsigned int unspecified:1;
-    /* ARM/AMBA: TrustZone Secure access
+    /*
+     * ARM/AMBA: TrustZone Secure access
      * x86: System Management Mode access
      */
     unsigned int secure:1;
+    /*
+     * ARM: ArmSecuritySpace.  This partially overlaps secure, but it is
+     * easier to have both fields to assist code that does not understand
+     * ARMv9 RME, or no specific knowledge of ARM at all (e.g. pflash).
+     */
+    unsigned int space:2;
     /* Memory access is usermode (unprivileged) */
     unsigned int user:1;
     /*