diff --git a/drivers/iommu/xen-iommu.c b/drivers/iommu/xen-iommu.c
index 255da427824606..986cf874319eb8 100644
--- a/drivers/iommu/xen-iommu.c
+++ b/drivers/iommu/xen-iommu.c
@@ -569,4 +569,5 @@ static int __init xen_iommu_init(void)
 	return 0;
 }
 
-module_init(xen_iommu_init);
+/* Must precede xen-pciback's fs_initcall bind, or the IOMMU core sees a bound device. */
+subsys_initcall_sync(xen_iommu_init);