diff --git a/iommu_ref_model/libiommu/include/iommu_translate.h b/iommu_ref_model/libiommu/include/iommu_translate.h
index 7e8bb318..e9a096c6 100644
--- a/iommu_ref_model/libiommu/include/iommu_translate.h
+++ b/iommu_ref_model/libiommu/include/iommu_translate.h
@@ -113,6 +113,6 @@ msi_address_translation(
     uint64_t gpa, uint8_t is_exec, device_context_t *DC, 
     uint8_t *is_msi, uint8_t *is_mrif, uint32_t *mrif_nid, uint64_t *dest_mrif_addr,
     uint32_t *cause, uint64_t *iotval2, uint64_t *pa, 
-    uint64_t *page_sz, gpte_t *g_pte, uint8_t TTYP );
+    uint64_t *page_sz, gpte_t *g_pte, uint8_t check_access_perms );
 
 #endif // __IOMMU_TRANSLATE_H__
diff --git a/iommu_ref_model/libiommu/src/iommu_msi_trans.c b/iommu_ref_model/libiommu/src/iommu_msi_trans.c
index ac61b497..703dd31d 100644
--- a/iommu_ref_model/libiommu/src/iommu_msi_trans.c
+++ b/iommu_ref_model/libiommu/src/iommu_msi_trans.c
@@ -21,7 +21,7 @@ msi_address_translation(
     uint64_t gpa, uint8_t is_exec, device_context_t *DC, 
     uint8_t *is_msi, uint8_t *is_mrif, uint32_t *mrif_nid, uint64_t *dest_mrif_addr,
     uint32_t *cause, uint64_t *iotval2, uint64_t *pa, 
-    uint64_t *page_sz, gpte_t *g_pte, uint8_t TTYP ) {
+    uint64_t *page_sz, gpte_t *g_pte, uint8_t check_access_perms ) {
 
     uint64_t A, m, I;
     uint8_t status;
@@ -170,7 +170,7 @@ msi_address_translation(
     //    transaction is treated as not requesting supervisor privilege.
     //    a. If the transaction is a Untranslated or Translated read-for-execute then stop
     //       and report "Instruction acccess fault" (cause = 1).
-    if ( is_exec && TTYP != PCIE_ATS_TRANSLATION_REQUEST ) {
+    if ( is_exec == 1 && check_access_perms == 1 ) {
         *cause = 1;
         return 1;
     }
diff --git a/iommu_ref_model/libiommu/src/iommu_translate.c b/iommu_ref_model/libiommu/src/iommu_translate.c
index cae1b77a..a4fea504 100644
--- a/iommu_ref_model/libiommu/src/iommu_translate.c
+++ b/iommu_ref_model/libiommu/src/iommu_translate.c
@@ -297,7 +297,7 @@ iommu_translate_iova(
     //     If a fault is detected by the MSI address translation process then stop and
     //     report the fault else the process continues at step 20.
     if ( msi_address_translation(gpa, is_exec, &DC, &is_msi, &is_mrif, &mrif_nid, &dest_mrif_addr,
-                                 &cause, &iotval2, &pa, &gst_page_sz, &g_pte, TTYP) )
+                                 &cause, &iotval2, &pa, &gst_page_sz, &g_pte, check_access_perms) )
         goto stop_and_report_fault;
     if ( is_msi == 1 ) goto skip_gpa_trans;