diff --git a/vmbase/src/layout/mod.rs b/vmbase/src/layout/mod.rs
index dd3e0e0..21c113a 100644
--- a/vmbase/src/layout/mod.rs
+++ b/vmbase/src/layout/mod.rs
@@ -20,6 +20,9 @@
 use core::ops::Range;
 use core::ptr::addr_of;
 
+/// First address that can't be translated by a level 1 TTBR0_EL1.
+pub const MAX_VIRT_ADDR: usize = 1 << 40;
+
 /// Get an address from a linker-defined symbol.
 #[macro_export]
 macro_rules! linker_addr {