selftests/x86/iopl.c

3  * iopl.c - Test case for a Linux on Xen 64-bit bug
181 	/* Probe for iopl support.  Note that iopl(0) works even as nonroot. */
182 	switch(iopl(3)) {
203 	if (iopl(0) != 0)
204 		err(1, "iopl(0)");
222 		if (iopl(3) != 0)
223 			err(1, "iopl");
250 	if (iopl(3) != 0)
251 		err(1, "iopl(3)");
260 	if (iopl(3) != 0) {
261 		printf("[FAIL]\tiopl(3) should work if iopl is already 3 even if unprivileged\n");
266 	if (iopl(0) != 0) {
267 		printf("[FAIL]\tiopl(0) should work if iopl is already 3 even if unprivileged\n");
272 	if (iopl(3) == 0) {
273 		printf("[FAIL]\tiopl(3) should fail if when unprivileged if iopl==0\n");