typedef struct vm_impl<Impl, Isa> impl vm{
    __code kpt_alloc_check_impl(Type* vm_impl, __code next(...));
    __code loaduvm_ptesize_checkvm_impl(Type* vm_impl,char* addr,  __code next(int ret, ...));
    __code loaduvm_check_PTE_SZ(Type* vm_impl, uint sz, uint i, uint n, struct inode* ip, uint pa, uint offset, __code next(int ret, ...));
    __code copyout_loop_check_n(Type* vm_impl, pde_t* pgdir, uint va, void* pp, uint len, uint va0, char* pa0, uint n, char* buf, __code next(...));
    __code clearpteu_check_ptevm_impl(Type* vm_impl, pde_t* pgdir, char* uva, __code next(int ret, ...));
    __code uva2ka_check_pe_types(Type* vm, pde_t* pgdir, char* uva, __code next(int ret, ...));
    __code copyout_loopvm_impl(Type* vm_impl, pde_t* pgdir, uint va, void* pp, uint len, uint va0, char* pa0,  __code next(int ret, ...));
    __code switchuvm_check_pgdirvm_impl(Type* vm_impl, proc_struct* p, __code next(...));
    __code init_inituvm_check_sz(Type* vm_impl, pde_t* pgdir, char* init, uint sz, __code next(...));
    __code loaduvm_loopvm_impl(Type* vm_impl, uint i, uint sz,__code next(int ret, ...));
    __code loaduvm_check_pgdir(Type* vm_impl, pte_t* pte, pde_t* pgdir, uint i, char* addr, uint pa, __code next(int ret, ...));
    __code loaduvm_exit(Type* vm_impl, __code next(int ret, ...));
    __code allocuvm_check_newszvm_impl(Type* vm_impl, pde_t* pgdir, uint oldsz, uint newsz, __code next(int ret, ...));
    __code allocuvm_loopvm_impl(Type* vm_impl, pde_t* pgdir, uint oldsz, uint newsz, char* mem, uint a, __code next(int ret, ...));
    __code copyuvm_check_nullvm_impl(Type* vm_impl, pde_t* pgdir, uint sz, __code next(int ret, ...));
    __code copyuvm_loopvm_impl(Type* vm_impl, pde_t* pgdir, uint sz, pde_t* d, pte_t* pte, uint pa, uint i, uint ap, char* mem, __code next(int ret, ...));
    __code copyuvm_loop_check_walkpgdir(Type* vm_impl, pde_t* pgdir, uint sz, pde_t* d, pte_t* pte, uint pa, uint i, uint ap, char* mem, __code next(int ret, ...));
    __code copyuvm_loop_check_pte(Type* vm_impl, pde_t* pgdir, uint sz, pde_t* d, pte_t* pte, uint pa, uint i, uint ap, char* mem, __code next(int ret, ...));
    __code copyuvm_loop_check_mem(Type* vm_impl, pde_t* pgdir, uint sz, pde_t* d, pte_t* pte, uint pa, uint i, uint ap, char* mem, __code next(int ret, ...));
    __code copyuvm_loop_check_mappages(Type* vm_impl, pde_t* pgdir, uint sz, pde_t* d, pte_t* pte, uint pa, uint i, uint ap, char* mem, __code next(int ret, ...));
    __code copyuvm_loop_bad(Type* vm_impl, pde_t* d, __code next(int ret, ...));
    __code uva2ka_check_pte_ap(Type* vm, pde_t* pgdir, char* uva, pte_t* pte, __code next(int ret, ...));
    __code paging_intvmvm_impl(Type* vm_impl, uint phy_low, uint phy_hi, __code next(...));
    __code copyout_loop_check_pa0(Type* vm_impl, pde_t* pgdir, uint va, void* pp, uint len, uint va0, char* pa0, uint n, __code next(int ret, ...));
    __code next(...);
} vm_impl;