diff --git a/model/riscv_addr_checks.sail b/model/riscv_addr_checks.sail
index 33091d93e..5ffd442bf 100644
--- a/model/riscv_addr_checks.sail
+++ b/model/riscv_addr_checks.sail
@@ -121,6 +121,13 @@ function ext_data_get_addr(base : regidx, offset : xlenbits, acc : AccessType(ex
   let addr = X(base) + offset in
   Ext_DataAddr_OK(addr)
 
+/* Default AMO data addr is just base register.
+   Extensions might override and add additional checks. */
+function ext_data_get_amo_addr(base : regidx, acc : AccessType(ext_access_type), width : amo_word_width)
+         -> Ext_DataAddr_Check(ext_data_addr_error) =
+  let addr = X(base) in
+  Ext_DataAddr_OK(addr)
+
 function ext_handle_data_check_error(err : ext_data_addr_error) -> unit =
   ()
 
diff --git a/model/riscv_insts_aext.sail b/model/riscv_insts_aext.sail
index fe5e7dce2..e9edaec23 100644
--- a/model/riscv_insts_aext.sail
+++ b/model/riscv_insts_aext.sail
@@ -298,9 +298,8 @@ function clause execute (AMO(op, aq, rl, rs2, rs1, width, rd)) = {
   if haveAtomics() then {
     /* Get the address, X(rs1) (no offset).
      * Some extensions perform additional checks on address validity.
-     * For obtaining virtual address, the width is not needed.
      */
-    match ext_data_get_addr(rs1, zeros(), ReadWrite(Data, Data), BYTE) {
+    match ext_data_get_amo_addr(rs1, ReadWrite(Data, Data), width) {
       Ext_DataAddr_Error(e)  => { ext_handle_data_check_error(e); RETIRE_FAIL },
       Ext_DataAddr_OK(vaddr) => {
         match translateAddr(vaddr, ReadWrite(Data, Data)) {