Constant DATA_BASE 

pub const DATA_BASE: u32 = 0x1000_0000; // 268_435_456u32

Re-exported PVM2 ABI layout constants (see [javm_cap::layout]). Guest virtual address where the data region begins. All data caps (stack / ro / rw / heap) and instance overlays live in [DATA_BASE, 4 GiB). At 256 MiB, well clear of the largest permitted code region.