diff --git a/xen/drivers/passthrough/vtd/dmar.c b/xen/drivers/passthrough/vtd/dmar.c
index 59a46cd1c6..b858fe7c80 100644
--- a/xen/drivers/passthrough/vtd/dmar.c
+++ b/xen/drivers/passthrough/vtd/dmar.c
@@ -1047,7 +1047,7 @@ int intel_iommu_get_reserved_device_memory(iommu_grdm_t *func, void *ctxt)
 
         rc = func(PFN_DOWN(rmrr->base_address),
                   PFN_UP(rmrr->end_address) - PFN_DOWN(rmrr->base_address),
-                  PCI_SBDF2(rmrr->segment, bdf), ctxt);
+                  PCI_SBDF2(rmrr->segment, bdf).sbdf, ctxt);
 
         if ( unlikely(rc < 0) )
             return rc;
diff --git a/xen/include/xen/pci.h b/xen/include/xen/pci.h
index b55cff954c..24bca85e41 100644
--- a/xen/include/xen/pci.h
+++ b/xen/include/xen/pci.h
@@ -36,7 +36,8 @@
 #define PCI_BDF2(b,df)  ((((b) & 0xff) << 8) | ((df) & 0xff))
 #define PCI_SBDF(s,b,d,f) \
     ((pci_sbdf_t){ .sbdf = (((s) & 0xffff) << 16) | PCI_BDF(b, d, f) })
-#define PCI_SBDF2(s,bdf) ((((s) & 0xffff) << 16) | ((bdf) & 0xffff))
+#define PCI_SBDF2(s,bdf) \
+    ((pci_sbdf_t){ .sbdf = (((s) & 0xffff) << 16) | ((bdf) & 0xffff) })
 #define PCI_SBDF3(s,b,df) ((((s) & 0xffff) << 16) | PCI_BDF2(b, df))
 
 typedef union {