MAXVA 44 kernel/memlayout.h #define TRAMPOLINE (MAXVA - PGSIZE) MAXVA 100 kernel/vm.c if(va >= MAXVA) MAXVA 126 kernel/vm.c if(va >= MAXVA) MAXVA 350 kernel/vm.c if(va0 >= MAXVA) MAXVA 2146 user/usertests.c volatile uint64 a = MAXVA;