vm_alloc_memseg
error = vm_alloc_memseg(ctx, segid, dom->size, NULL,
error = vm_alloc_memseg(ctx, segid, len, name, 0, NULL, 0);
error = vm_alloc_memseg(sc->vm, mseg->segid, mseg->len, sysmem, domainset);
int vm_alloc_memseg(struct vm *vm, int ident, size_t len, bool sysmem,