diff --git a/include/exec/memattrs.h b/include/exec/memattrs.h
index 14cdd8d582..e27c18f3dc 100644
--- a/include/exec/memattrs.h
+++ b/include/exec/memattrs.h
@@ -52,6 +52,11 @@ typedef struct MemTxAttrs {
     unsigned int memory:1;
     /* Requester ID (for MSI for example) */
     unsigned int requester_id:16;
+
+    /*
+     * PID (PCI PASID) support: Limited to 8 bits process identifier.
+     */
+    unsigned int pid:8;
 } MemTxAttrs;
 
 /* Bus masters which don't specify any attributes will get this,