UPPER_OFF
for (uintptr_t gpa = UPPER_OFF; gpa < UPPER_OFF + UPPER_SZ; gpa++) {
volatile uint8_t *ptr = guest_mem + UPPER_OFF;
res = vm_munmap_memseg(ctx, UPPER_OFF, UPPER_SZ);
res = vm_mmap_memseg(ctx, UPPER_OFF, MSEG_HIGH, 0, UPPER_SZ, PROT_ALL);