pub const CTX_VA: u64 = _; // 549_755_813_888u64Expand description
JitContext lives above the PVM u32 address space (no bounds check
on guest mem — the full low 4 GiB of native VA belongs to the
program). CTX is reached via RIP-relative [rip+disp32], which
gives ±2 GiB range from the JIT code, so CTX must be adjacent
to the JIT region.
In the nub-x86 microkernel, CTX and the per-Image JIT arena both
live in PML4 slot 1 (base 512 GiB). Sharing one PML4 slot lets
the Image’s PDPT subtree be cached as a template across all
Instances (per-call PT just shallow-clones the slot’s entry). MEM
stays in PML4[0] at VA 0 so PVM addr == native VA still holds.