diff --git a/sys/dev/xen/blkback/blkback.c b/sys/dev/xen/blkback/blkback.c
index 1273961..531c53f 100644
--- a/sys/dev/xen/blkback/blkback.c
+++ b/sys/dev/xen/blkback/blkback.c
@@ -3070,7 +3070,7 @@ xbb_alloc_communication_mem(struct xbb_softc *xbb)
 	xbb->pseudo_phys_res_id = 0;
 	xbb->pseudo_phys_res = bus_alloc_resource(xbb->dev, SYS_RES_MEMORY,
 						  &xbb->pseudo_phys_res_id,
-						  0, ~0, xbb->kva_size,
+						  0x100000000, ~0ul, xbb->kva_size,
 						  RF_ACTIVE);
 	if (xbb->pseudo_phys_res == NULL) {
 		xbb->kva = 0;
diff --git a/sys/dev/xen/grant_table/grant_table.c b/sys/dev/xen/grant_table/grant_table.c
index 2511657..b9ff6e7 100644
--- a/sys/dev/xen/grant_table/grant_table.c
+++ b/sys/dev/xen/grant_table/grant_table.c
@@ -628,7 +628,7 @@ gnttab_resume(device_t dev)
 		    ("No resume frames and no device provided"));
 
 		gnttab_pseudo_phys_res = bus_alloc_resource(dev,
-		    SYS_RES_MEMORY, &gnttab_pseudo_phys_res_id, 0, ~0,
+		    SYS_RES_MEMORY, &gnttab_pseudo_phys_res_id, 0x100000000, ~0ul,
 		    PAGE_SIZE * max_nr_gframes, RF_ACTIVE);
 		if (gnttab_pseudo_phys_res == NULL)
 			panic("Unable to reserve physical memory for gnttab");
diff --git a/sys/dev/xen/netback/netback.c b/sys/dev/xen/netback/netback.c
index 63337ad..7aee790 100644
--- a/sys/dev/xen/netback/netback.c
+++ b/sys/dev/xen/netback/netback.c
@@ -832,7 +832,7 @@ xnb_alloc_communication_mem(struct xnb_softc *xnb)
 	xnb->pseudo_phys_res_id = 0;
 	xnb->pseudo_phys_res = bus_alloc_resource(xnb->dev, SYS_RES_MEMORY,
 						  &xnb->pseudo_phys_res_id,
-						  0, ~0, xnb->kva_size,
+						  0x100000000, ~0ul, xnb->kva_size,
 						  RF_ACTIVE);
 	if (xnb->pseudo_phys_res == NULL) {
 		xnb->kva = 0;
diff --git a/sys/dev/xen/privcmd/privcmd.c b/sys/dev/xen/privcmd/privcmd.c
index 761fb03..8bdfce1 100644
--- a/sys/dev/xen/privcmd/privcmd.c
+++ b/sys/dev/xen/privcmd/privcmd.c
@@ -204,7 +204,7 @@ privcmd_mmap_single(struct cdev *cdev, vm_ooffset_t *offset, vm_size_t size,
 	map->pseudo_phys_res_id = 0;
 
 	map->pseudo_phys_res = bus_alloc_resource(privcmd_dev, SYS_RES_MEMORY,
-	    &map->pseudo_phys_res_id, 0, ~0, size, RF_ACTIVE);
+	    &map->pseudo_phys_res_id, 0x100000000, ~0ul, size, RF_ACTIVE);
 	if (map->pseudo_phys_res == NULL) {
 		free(map, M_PRIVCMD);
 		return (ENOMEM);