selftests/x86/iopl: Extend test to cover IOPL emulation (e638ad00) · Commits · 戴 / test

tools/testing/selftests/x86/iopl.c

+118 −11

Original line number	Diff line number	Diff line
		@@ -35,6 +35,16 @@ static void sethandler(int sig, void (handler)(int, siginfo_t , void *),

		}

		static void clearhandler(int sig)
		{
		struct sigaction sa;
		memset(&sa, 0, sizeof(sa));
		sa.sa_handler = SIG_DFL;
		sigemptyset(&sa.sa_mask);
		if (sigaction(sig, &sa, 0))
		err(1, "sigaction");
		}

		static jmp_buf jmpbuf;

		static void sigsegv(int sig, siginfo_t si, void ctx_void)
		@@ -42,25 +52,128 @@ static void sigsegv(int sig, siginfo_t si, void ctx_void)
		siglongjmp(jmpbuf, 1);
		}

		static bool try_outb(unsigned short port)
		{
		sethandler(SIGSEGV, sigsegv, SA_RESETHAND);
		if (sigsetjmp(jmpbuf, 1) != 0) {
		return false;
		} else {
		asm volatile ("outb %%al, %w[port]"
		: : [port] "Nd" (port), "a" (0));
		return true;
		}
		clearhandler(SIGSEGV);
		}

		static void expect_ok_outb(unsigned short port)
		{
		if (!try_outb(port)) {
		printf("[FAIL]\toutb to 0x%02hx failed\n", port);
		exit(1);
		}

		printf("[OK]\toutb to 0x%02hx worked\n", port);
		}

		static void expect_gp_outb(unsigned short port)
		{
		if (try_outb(port)) {
		printf("[FAIL]\toutb to 0x%02hx worked\n", port);
		nerrs++;
		}

		printf("[OK]\toutb to 0x%02hx failed\n", port);
		}

		static bool try_cli(void)
		{
		sethandler(SIGSEGV, sigsegv, SA_RESETHAND);
		if (sigsetjmp(jmpbuf, 1) != 0) {
		return false;
		} else {
		asm volatile ("cli");
		return true;
		}
		clearhandler(SIGSEGV);
		}

		static bool try_sti(void)
		{
		sethandler(SIGSEGV, sigsegv, SA_RESETHAND);
		if (sigsetjmp(jmpbuf, 1) != 0) {
		return false;
		} else {
		asm volatile ("sti");
		return true;
		}
		clearhandler(SIGSEGV);
		}

		static void expect_gp_sti(void)
		{
		if (try_sti()) {
		printf("[FAIL]\tSTI worked\n");
		nerrs++;
		} else {
		printf("[OK]\tSTI faulted\n");
		}
		}

		static void expect_gp_cli(void)
		{
		if (try_cli()) {
		printf("[FAIL]\tCLI worked\n");
		nerrs++;
		} else {
		printf("[OK]\tCLI faulted\n");
		}
		}

		int main(void)
		{
		cpu_set_t cpuset;

		CPU_ZERO(&cpuset);
		CPU_SET(0, &cpuset);
		if (sched_setaffinity(0, sizeof(cpuset), &cpuset) != 0)
		err(1, "sched_setaffinity to CPU 0");

		/* Probe for iopl support. Note that iopl(0) works even as nonroot. */
		if (iopl(3) != 0) {
		switch(iopl(3)) {
		case 0:
		break;
		case -ENOSYS:
		printf("[OK]\tiopl() nor supported\n");
		return 0;
		default:
		printf("[OK]\tiopl(3) failed (%d) -- try running as root\n",
		errno);
		return 0;
		}

		/* Restore our original state prior to starting the test. */
		/* Make sure that CLI/STI are blocked even with IOPL level 3 */
		expect_gp_cli();
		expect_gp_sti();
		expect_ok_outb(0x80);

		/* Establish an I/O bitmap to test the restore */
		if (ioperm(0x80, 1, 1) != 0)
		err(1, "ioperm(0x80, 1, 1) failed\n");

		/* Restore our original state prior to starting the fork test. */
		if (iopl(0) != 0)
		err(1, "iopl(0)");

		/*
		* Verify that IOPL emulation is disabled and the I/O bitmap still
		* works.
		*/
		expect_ok_outb(0x80);
		expect_gp_outb(0xed);
		/* Drop the I/O bitmap */
		if (ioperm(0x80, 1, 0) != 0)
		err(1, "ioperm(0x80, 1, 0) failed\n");

		pid_t child = fork();
		if (child == -1)
		err(1, "fork");
		@@ -90,14 +203,9 @@ int main(void)

		printf("[RUN]\tparent: write to 0x80 (should fail)\n");

		sethandler(SIGSEGV, sigsegv, 0);
		if (sigsetjmp(jmpbuf, 1) != 0) {
		printf("[OK]\twrite was denied\n");
		} else {
		asm volatile ("outb %%al, $0x80" : : "a" (0));
		printf("[FAIL]\twrite was allowed\n");
		nerrs++;
		}
		expect_gp_outb(0x80);
		expect_gp_cli();
		expect_gp_sti();

		/* Test the capability checks. */
		printf("\tiopl(3)\n");
		@@ -133,4 +241,3 @@ int main(void)
		done:
		return nerrs ? 1 : 0;
		}

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