fixup

Signed-off-by: Nirjhar Roy <nirjhar.roy@fortanix.com>

common/src/arch/x86_64/cpu.c

@@ -1,11 +1,9 @@
 /* SPDX-License-Identifier: LGPL-3.0-or-later */
-/* Copyright (C) 2022 Fortnanix Inc
+/* Copyright (C) 2022 Fortanix Inc
  *                    Nirjhar Roy <nirjhar.roy@fortanix.com>
  */
 
-/* This file contains functions that check various features and flags
- * specific to x86
- */
+/* This file contains functions that check various features and flags specific to x86 */
 
 #include <stddef.h>
 
@@ -31,9 +29,6 @@ bool is_x86_instr_legacy_prefix(uint8_t op) {
                              0x66, /*  Operand-size override prefix */
                              /* Group 3 */
                              0x67, /* Address-size override prefix  */
-                             /* The rest of the prefixes aren't really applicable
-                              * for the instruction(s) we are checking.
-                              */
                             };
     for (size_t i = 0; i < ARRAY_SIZE(prefix_list); i++) {
         if (op == prefix_list[i])

libos/src/bookkeep/libos_signal.c

@@ -479,13 +479,11 @@ static bool is_in_out(PAL_CONTEXT* context) {
 }
 
 static bool maybe_raise_sigsegv(PAL_CONTEXT* context) {
-    /* Executing I/O instructions (e.g., in/out) inside an SGX enclave
-     * generates a #UD fault. Gramine's PAL tries to handle this exception and
-     * propogates it to LibOS/app as a SIGILL signal.
-     *
-     * However, I/O instructions result in a #GP fault (which raises a SIGSEGV
-     * signal) if I/O is not permitted. Let Gramine emulate these instructions
-     * as if they end up in SIGSEGV. This helps some apps, e.g. `lscpu`.
+    /* Executing I/O instructions (e.g., in/out) inside an SGX enclave generates a #UD fault.
+     * Gramine's PAL tries to handle this exception and propogates it to LibOS/app as a SIGILL
+     * signal. However, I/O instructions result in a #GP fault (which raises a SIGSEGV signal) if
+     * I/O is not permitted. Let Gramine emulate these instructions as if they end up in SIGSEGV.
+     * This helps some apps, e.g. `lscpu`.
      */
     return is_in_out(context);
 }

libos/test/regression/in_out_instruction_test.c

@@ -1,6 +1,5 @@
-/* Test description: this test verifies that in and out instructions
- * correctly generate SIGSEGV. This raises SIGSEGV once for IN and once for OUT
- * and then counts if number of SIGSEGVs are 2.
+/* Test description: this test verifies that in and out instructions correctly generate SIGSEGV.
+ * This raises SIGSEGV once for IN and once for OUT and then counts if number of SIGSEGVs is 2.
  */
 #define _XOPEN_SOURCE 700
 #define _POSIX_C_SOURCE 200809
@@ -26,21 +25,20 @@ static void fault_handler(int signum) {
 int main(void) {
     struct sigaction int_handler = {.sa_handler=fault_handler,
                                     .sa_flags = SA_RESTART};
-    int value = 0;
-    int port = 0;
-    sigaction(SIGSEGV, &int_handler, 0);
+    unsigned char value = 0;
+    unsigned short port = 0x3F8;
+    CHECK(sigaction(SIGSEGV, &int_handler, NULL));
     if (sigsetjmp(g_point, 1) == 0) {
-        __asm__ volatile("in %1, %0" : "=a"(value) : "d"(port));
+        __asm__ volatile("inb %1, %0" : "=a"(value) : "d"(port));
     }
     puts("handled IN instruction");
     if (sigsetjmp(g_point, 1) == 0) {
-        port = 0;
-        __asm__ volatile("out %0, %1" : "=a"(value) : "d"(port));
+        __asm__ volatile("outb %0, %1" : : "a"(value), "d"(port));
     }
     puts("handled OUT instruction");
-    if (g_sigsegv_triggered == EXPECTED_NUM_SIGSEGVS)
-        puts("SIGSEGV TEST OK");
-    else
-        puts("SIGSEGV TEST FAILED");
+    if (g_sigsegv_triggered != EXPECTED_NUM_SIGSEGVS)
+        errx(1, "Expected %d number of SIGSEGVs, but got only %d", EXPECTED_NUM_SIGSEGVS,
+             g_sigsegv_triggered);
+    puts("SIGSEGV TEST OK");
     return 0;
 }