1 // SPDX-License-Identifier: GPL-2.0
2 #include <fcntl.h>
3 #include <stdio.h>
4 #include <stdlib.h>
5 #include <string.h>
6 #include <sys/ioctl.h>
7
8 #include "kvm_util.h"
9 #include "processor.h"
10 #include "kselftest.h"
11
12 #define CPUID_MWAIT (1u << 3)
13
14 enum monitor_mwait_testcases {
15 MWAIT_QUIRK_DISABLED = BIT(0),
16 MISC_ENABLES_QUIRK_DISABLED = BIT(1),
17 MWAIT_DISABLED = BIT(2),
18 CPUID_DISABLED = BIT(3),
19 TEST_MAX = CPUID_DISABLED * 2 - 1,
20 };
21
22 /*
23 * If both MWAIT and its quirk are disabled, MONITOR/MWAIT should #UD, in all
24 * other scenarios KVM should emulate them as nops.
25 */
26 #define GUEST_ASSERT_MONITOR_MWAIT(insn, testcase, vector) \
27 do { \
28 bool fault_wanted = ((testcase) & MWAIT_QUIRK_DISABLED) && \
29 ((testcase) & MWAIT_DISABLED); \
30 \
31 if (fault_wanted) \
32 __GUEST_ASSERT((vector) == UD_VECTOR, \
33 "Expected #UD on " insn " for testcase '0x%x', got '0x%x'", \
34 testcase, vector); \
35 else \
36 __GUEST_ASSERT(!(vector), \
37 "Expected success on " insn " for testcase '0x%x', got '0x%x'", \
38 testcase, vector); \
39 } while (0)
40
guest_monitor_wait(void * arg)41 static void guest_monitor_wait(void *arg)
42 {
43 int testcase = (int) (long) arg;
44 u8 vector;
45
46 u64 val = rdmsr(MSR_IA32_MISC_ENABLE) & ~MSR_IA32_MISC_ENABLE_MWAIT;
47 if (!(testcase & MWAIT_DISABLED))
48 val |= MSR_IA32_MISC_ENABLE_MWAIT;
49 wrmsr(MSR_IA32_MISC_ENABLE, val);
50
51 __GUEST_ASSERT(this_cpu_has(X86_FEATURE_MWAIT) == !(testcase & MWAIT_DISABLED),
52 "Expected CPUID.MWAIT %s\n",
53 (testcase & MWAIT_DISABLED) ? "cleared" : "set");
54
55 /*
56 * Arbitrarily MONITOR this function, SVM performs fault checks before
57 * intercept checks, so the inputs for MONITOR and MWAIT must be valid.
58 */
59 vector = kvm_asm_safe("monitor", "a"(guest_monitor_wait), "c"(0), "d"(0));
60 GUEST_ASSERT_MONITOR_MWAIT("MONITOR", testcase, vector);
61
62 vector = kvm_asm_safe("mwait", "a"(guest_monitor_wait), "c"(0), "d"(0));
63 GUEST_ASSERT_MONITOR_MWAIT("MWAIT", testcase, vector);
64
65 GUEST_DONE();
66 }
67
main(int argc,char * argv[])68 int main(int argc, char *argv[])
69 {
70 uint64_t disabled_quirks;
71 struct kvm_vcpu *vcpu;
72 struct kvm_vm *vm;
73 struct ucall uc;
74 int testcase;
75 char test[80];
76
77 TEST_REQUIRE(kvm_has_cap(KVM_CAP_DISABLE_QUIRKS2));
78
79 ksft_print_header();
80 ksft_set_plan(12);
81 for (testcase = 0; testcase <= TEST_MAX; testcase++) {
82 vm = vm_create_with_one_vcpu(&vcpu, guest_monitor_wait);
83 vcpu_args_set(vcpu, 1, (void *)(long)testcase);
84
85 disabled_quirks = 0;
86 if (testcase & MWAIT_QUIRK_DISABLED) {
87 disabled_quirks |= KVM_X86_QUIRK_MWAIT_NEVER_UD_FAULTS;
88 strcpy(test, "MWAIT can fault");
89 } else {
90 strcpy(test, "MWAIT never faults");
91 }
92 if (testcase & MISC_ENABLES_QUIRK_DISABLED) {
93 disabled_quirks |= KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT;
94 strcat(test, ", MISC_ENABLE updates CPUID");
95 } else {
96 strcat(test, ", no CPUID updates");
97 }
98
99 vm_enable_cap(vm, KVM_CAP_DISABLE_QUIRKS2, disabled_quirks);
100
101 if (!(testcase & MISC_ENABLES_QUIRK_DISABLED) &&
102 (!!(testcase & CPUID_DISABLED) ^ !!(testcase & MWAIT_DISABLED)))
103 continue;
104
105 if (testcase & CPUID_DISABLED) {
106 strcat(test, ", CPUID clear");
107 vcpu_clear_cpuid_feature(vcpu, X86_FEATURE_MWAIT);
108 } else {
109 strcat(test, ", CPUID set");
110 vcpu_set_cpuid_feature(vcpu, X86_FEATURE_MWAIT);
111 }
112
113 if (testcase & MWAIT_DISABLED)
114 strcat(test, ", MWAIT disabled");
115
116 vcpu_run(vcpu);
117 TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
118
119 switch (get_ucall(vcpu, &uc)) {
120 case UCALL_ABORT:
121 /* Detected in vcpu_run */
122 break;
123 case UCALL_DONE:
124 ksft_test_result_pass("%s\n", test);
125 break;
126 default:
127 TEST_FAIL("Unknown ucall %lu", uc.cmd);
128 break;
129 }
130 kvm_vm_free(vm);
131 }
132 ksft_finished();
133
134 return 0;
135 }
136