diff --git a/hw/xen/xen_pt_config_init.c b/hw/xen/xen_pt_config_init.c
index c5c4e943a8..4758514ddf 100644
--- a/hw/xen/xen_pt_config_init.c
+++ b/hw/xen/xen_pt_config_init.c
@@ -1965,11 +1965,12 @@ static void xen_pt_config_reg_init(XenPCIPassthroughState *s,
 
         if ((data & host_mask) != (val & host_mask)) {
             uint32_t new_val;
-
-            /* Mask out host (including past size). */
-            new_val = val & host_mask;
-            /* Merge emulated ones (excluding the non-emulated ones). */
-            new_val |= data & host_mask;
+            /*
+             * Merge the emulated bits (data) with the host bits (val)
+             * and mask out the bits past size to enable restoration
+             * of the proper value for logging below.
+             */
+            new_val = XEN_PT_MERGE_VALUE(val, data, host_mask) & size_mask;
             /* Leave intact host and emulated values past the size - even though
              * we do not care as we write per reg->size granularity, but for the
              * logging below lets have the proper value. */
@@ -2031,12 +2032,16 @@ void xen_pt_config_init(XenPCIPassthroughState *s, Error **errp)
             }
         }
 
-        /*
-         * By default we will trap up to 0x40 in the cfg space.
-         * If an intel device is pass through we need to trap 0xfc,
-         * therefore the size should be 0xff.
-         */
         if (xen_pt_emu_reg_grps[i].grp_id == XEN_PCI_INTEL_OPREGION) {
+            if (!is_igd_vga_passthrough(&s->real_device) ||
+                s->real_device.vendor_id != PCI_VENDOR_ID_INTEL) {
+                continue;
+            }
+            /*
+             * By default we will trap up to 0x40 in the cfg space.
+             * If an intel device is pass through we need to trap 0xfc,
+             * therefore the size should be 0xff.
+             */
             reg_grp_offset = XEN_PCI_INTEL_OPREGION;
         }