selftests: kvm: revamp MONITOR/MWAIT tests

Run each testcase in a separate VMs to cover more possibilities;
move WRMSR close to MONITOR/MWAIT to test updating CPUID bits
while in the VM.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

Author: bonzini

tools/testing/selftests/kvm/x86/monitor_mwait_test.c

@@ -7,13 +7,16 @@
 
 #include "kvm_util.h"
 #include "processor.h"
+#include "kselftest.h"
 
 #define CPUID_MWAIT (1u << 3)
 
 enum monitor_mwait_testcases {
 	MWAIT_QUIRK_DISABLED = BIT(0),
 	MISC_ENABLES_QUIRK_DISABLED = BIT(1),
 	MWAIT_DISABLED = BIT(2),
+	CPUID_DISABLED = BIT(3),
+	TEST_MAX = CPUID_DISABLED * 2 - 1,
 };
 
 /*
@@ -35,11 +38,19 @@ do {									\
 			       testcase, vector);			\
 } while (0)
 
-static void guest_monitor_wait(int testcase)
+static void guest_monitor_wait(void *arg)
 {
+	int testcase = (int) (long) arg;
 	u8 vector;
 
-	GUEST_SYNC(testcase);
+	u64 val = rdmsr(MSR_IA32_MISC_ENABLE) & ~MSR_IA32_MISC_ENABLE_MWAIT;
+	if (!(testcase & MWAIT_DISABLED))
+		val |= MSR_IA32_MISC_ENABLE_MWAIT;
+	wrmsr(MSR_IA32_MISC_ENABLE, val);
+
+	__GUEST_ASSERT(this_cpu_has(X86_FEATURE_MWAIT) == !(testcase & MWAIT_DISABLED),
+		       "Expected CPUID.MWAIT %s\n",
+		       (testcase & MWAIT_DISABLED) ? "cleared" : "set");
 
 	/*
 	 * Arbitrarily MONITOR this function, SVM performs fault checks before
@@ -50,19 +61,6 @@ static void guest_monitor_wait(int testcase)
 
 	vector = kvm_asm_safe("mwait", "a"(guest_monitor_wait), "c"(0), "d"(0));
 	GUEST_ASSERT_MONITOR_MWAIT("MWAIT", testcase, vector);
-}
-
-static void guest_code(void)
-{
-	guest_monitor_wait(MWAIT_DISABLED);
-
-	guest_monitor_wait(MWAIT_QUIRK_DISABLED | MWAIT_DISABLED);
-
-	guest_monitor_wait(MISC_ENABLES_QUIRK_DISABLED | MWAIT_DISABLED);
-	guest_monitor_wait(MISC_ENABLES_QUIRK_DISABLED);
-
-	guest_monitor_wait(MISC_ENABLES_QUIRK_DISABLED | MWAIT_QUIRK_DISABLED | MWAIT_DISABLED);
-	guest_monitor_wait(MISC_ENABLES_QUIRK_DISABLED | MWAIT_QUIRK_DISABLED);
 
 	GUEST_DONE();
 }
@@ -74,56 +72,64 @@ int main(int argc, char *argv[])
 	struct kvm_vm *vm;
 	struct ucall uc;
 	int testcase;
+	char test[80];
 
-	TEST_REQUIRE(this_cpu_has(X86_FEATURE_MWAIT));
 	TEST_REQUIRE(kvm_has_cap(KVM_CAP_DISABLE_QUIRKS2));
 
-	vm = vm_create_with_one_vcpu(&vcpu, guest_code);
-	vcpu_clear_cpuid_feature(vcpu, X86_FEATURE_MWAIT);
+	ksft_print_header();
+	ksft_set_plan(12);
+	for (testcase = 0; testcase <= TEST_MAX; testcase++) {
+		vm = vm_create_with_one_vcpu(&vcpu, guest_monitor_wait);
+		vcpu_args_set(vcpu, 1, (void *)(long)testcase);
+
+		disabled_quirks = 0;
+		if (testcase & MWAIT_QUIRK_DISABLED) {
+			disabled_quirks |= KVM_X86_QUIRK_MWAIT_NEVER_UD_FAULTS;
+			strcpy(test, "MWAIT can fault");
+		} else {
+			strcpy(test, "MWAIT never faults");
+		}
+		if (testcase & MISC_ENABLES_QUIRK_DISABLED) {
+			disabled_quirks |= KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT;
+			strcat(test, ", MISC_ENABLE updates CPUID");
+		} else {
+			strcat(test, ", no CPUID updates");
+		}
+
+		vm_enable_cap(vm, KVM_CAP_DISABLE_QUIRKS2, disabled_quirks);
+
+		if (!(testcase & MISC_ENABLES_QUIRK_DISABLED) &&
+		    (!!(testcase & CPUID_DISABLED) ^ !!(testcase & MWAIT_DISABLED)))
+			continue;
+
+		if (testcase & CPUID_DISABLED) {
+			strcat(test, ", CPUID clear");
+			vcpu_clear_cpuid_feature(vcpu, X86_FEATURE_MWAIT);
+		} else {
+			strcat(test, ", CPUID set");
+			vcpu_set_cpuid_feature(vcpu, X86_FEATURE_MWAIT);
+		}
+
+		if (testcase & MWAIT_DISABLED)
+			strcat(test, ", MWAIT disabled");
 
-	while (1) {
 		vcpu_run(vcpu);
 		TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
 
 		switch (get_ucall(vcpu, &uc)) {
-		case UCALL_SYNC:
-			testcase = uc.args[1];
-			break;
 		case UCALL_ABORT:
-			REPORT_GUEST_ASSERT(uc);
-			goto done;
+			/* Detected in vcpu_run */
+			break;
 		case UCALL_DONE:
-			goto done;
+			ksft_test_result_pass("%s\n", test);
+			break;
 		default:
 			TEST_FAIL("Unknown ucall %lu", uc.cmd);
-			goto done;
-		}
-
-		disabled_quirks = 0;
-		if (testcase & MWAIT_QUIRK_DISABLED)
-			disabled_quirks |= KVM_X86_QUIRK_MWAIT_NEVER_UD_FAULTS;
-		if (testcase & MISC_ENABLES_QUIRK_DISABLED)
-			disabled_quirks |= KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT;
-		vm_enable_cap(vm, KVM_CAP_DISABLE_QUIRKS2, disabled_quirks);
-
-		/*
-		 * If the MISC_ENABLES quirk (KVM neglects to update CPUID to
-		 * enable/disable MWAIT) is disabled, toggle the ENABLE_MWAIT
-		 * bit in MISC_ENABLES accordingly.  If the quirk is enabled,
-		 * the only valid configuration is MWAIT disabled, as CPUID
-		 * can't be manually changed after running the vCPU.
-		 */
-		if (!(testcase & MISC_ENABLES_QUIRK_DISABLED)) {
-			TEST_ASSERT(testcase & MWAIT_DISABLED,
-				    "Can't toggle CPUID features after running vCPU");
-			continue;
+			break;
 		}
-
-		vcpu_set_msr(vcpu, MSR_IA32_MISC_ENABLE,
-			     (testcase & MWAIT_DISABLED) ? 0 : MSR_IA32_MISC_ENABLE_MWAIT);
+		kvm_vm_free(vm);
 	}
+	ksft_finished();
 
-done:
-	kvm_vm_free(vm);
 	return 0;
 }