KVM: selftests: Convert the MONITOR/MWAIT test to use printf guest asserts

Convert x86's MONITOR/MWAIT test to use printf-based guest asserts.  Add a
macro to handle reporting failures to reduce the amount of copy+paste
needed for MONITOR vs. MWAIT.

Link: https://lore.kernel.org/r/20230729003643.1053367-25-seanjc@google.comSigned-off-by: Sean Christopherson <seanjc@google.com>

tools/testing/selftests/kvm/x86_64/monitor_mwait_test.c

 // SPDX-License-Identifier: GPL-2.0
+#define USE_GUEST_ASSERT_PRINTF 1
+
 #include <fcntl.h>
 #include <stdio.h>
 #include <stdlib.h>
@@ -16,14 +18,25 @@ enum monitor_mwait_testcases {
 	MWAIT_DISABLED = BIT(2),
 };
 
+/*
+ * If both MWAIT and its quirk are disabled, MONITOR/MWAIT should #UD, in all
+ * other scenarios KVM should emulate them as nops.
+ */
+#define GUEST_ASSERT_MONITOR_MWAIT(insn, testcase, vector)		\
+do {									\
+	bool fault_wanted = ((testcase) & MWAIT_QUIRK_DISABLED) &&	\
+			    ((testcase) & MWAIT_DISABLED);		\
+									\
+	if (fault_wanted)						\
+		__GUEST_ASSERT((vector) == UD_VECTOR,			\
+			       "Expected #UD on " insn " for testcase '0x%x', got '0x%x'", vector); \
+	else								\
+		__GUEST_ASSERT(!(vector),				\
+			       "Expected success on " insn " for testcase '0x%x', got '0x%x'", vector); \
+} while (0)
+
 static void guest_monitor_wait(int testcase)
 {
-	/*
-	 * If both MWAIT and its quirk are disabled, MONITOR/MWAIT should #UD,
-	 * in all other scenarios KVM should emulate them as nops.
-	 */
-	bool fault_wanted = (testcase & MWAIT_QUIRK_DISABLED) &&
-			    (testcase & MWAIT_DISABLED);
 	u8 vector;
 
 	GUEST_SYNC(testcase);
@@ -33,16 +46,10 @@ static void guest_monitor_wait(int testcase)
 	 * intercept checks, so the inputs for MONITOR and MWAIT must be valid.
 	 */
 	vector = kvm_asm_safe("monitor", "a"(guest_monitor_wait), "c"(0), "d"(0));
-	if (fault_wanted)
-		GUEST_ASSERT_2(vector == UD_VECTOR, testcase, vector);
-	else
-		GUEST_ASSERT_2(!vector, testcase, vector);
+	GUEST_ASSERT_MONITOR_MWAIT("MONITOR", testcase, vector);
 
 	vector = kvm_asm_safe("mwait", "a"(guest_monitor_wait), "c"(0), "d"(0));
-	if (fault_wanted)
-		GUEST_ASSERT_2(vector == UD_VECTOR, testcase, vector);
-	else
-		GUEST_ASSERT_2(!vector, testcase, vector);
+	GUEST_ASSERT_MONITOR_MWAIT("MWAIT", testcase, vector);
 }
 
 static void guest_code(void)
@@ -85,7 +92,7 @@ int main(int argc, char *argv[])
 			testcase = uc.args[1];
 			break;
 		case UCALL_ABORT:
-			REPORT_GUEST_ASSERT_2(uc, "testcase = %lx, vector = %ld");
+			REPORT_GUEST_ASSERT(uc);
 			goto done;
 		case UCALL_DONE:
 			goto done;