atoi_non_negative
atoi_non_negative("Idle pages warning",
test_args.migration_freq_ms = atoi_non_negative("Frequency", optarg);
test_args.timer_err_margin_us = atoi_non_negative("Error Margin", optarg);
nr_irqs = atoi_non_negative("Number of IRQs", optarg);
p.write_percent = atoi_non_negative("Write percentage", optarg);
mode = atoi_non_negative("Guest mode ID", arg);
u32 pcpu = atoi_non_negative("CPU number", cpu_str);
p.delay = atoi_non_negative("Delay", optarg);
targs->tlast = atoi_non_negative("Last test", optarg);
targs->seconds = atoi_non_negative("Test length", optarg);
targs->tfirst = atoi_non_negative("First test", optarg);