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1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* | |
3 | * Copyright (C) 2020, Google LLC. | |
4 | * | |
5 | * Tests for KVM paravirtual feature disablement | |
6 | */ | |
7 | #include <asm/kvm_para.h> | |
8 | #include <linux/kvm_para.h> | |
9 | #include <stdint.h> | |
10 | ||
11 | #include "test_util.h" | |
12 | #include "kvm_util.h" | |
13 | #include "processor.h" | |
14 | ||
15 | extern unsigned char rdmsr_start; | |
16 | extern unsigned char rdmsr_end; | |
17 | ||
18 | static u64 do_rdmsr(u32 idx) | |
19 | { | |
20 | u32 lo, hi; | |
21 | ||
22 | asm volatile("rdmsr_start: rdmsr;" | |
23 | "rdmsr_end:" | |
24 | : "=a"(lo), "=c"(hi) | |
25 | : "c"(idx)); | |
26 | ||
27 | return (((u64) hi) << 32) | lo; | |
28 | } | |
29 | ||
30 | extern unsigned char wrmsr_start; | |
31 | extern unsigned char wrmsr_end; | |
32 | ||
33 | static void do_wrmsr(u32 idx, u64 val) | |
34 | { | |
35 | u32 lo, hi; | |
36 | ||
37 | lo = val; | |
38 | hi = val >> 32; | |
39 | ||
40 | asm volatile("wrmsr_start: wrmsr;" | |
41 | "wrmsr_end:" | |
42 | : : "a"(lo), "c"(idx), "d"(hi)); | |
43 | } | |
44 | ||
45 | static int nr_gp; | |
46 | ||
47 | static void guest_gp_handler(struct ex_regs *regs) | |
48 | { | |
49 | unsigned char *rip = (unsigned char *)regs->rip; | |
50 | bool r, w; | |
51 | ||
52 | r = rip == &rdmsr_start; | |
53 | w = rip == &wrmsr_start; | |
54 | GUEST_ASSERT(r || w); | |
55 | ||
56 | nr_gp++; | |
57 | ||
58 | if (r) | |
59 | regs->rip = (uint64_t)&rdmsr_end; | |
60 | else | |
61 | regs->rip = (uint64_t)&wrmsr_end; | |
62 | } | |
63 | ||
64 | struct msr_data { | |
65 | uint32_t idx; | |
66 | const char *name; | |
67 | }; | |
68 | ||
69 | #define TEST_MSR(msr) { .idx = msr, .name = #msr } | |
70 | #define UCALL_PR_MSR 0xdeadbeef | |
71 | #define PR_MSR(msr) ucall(UCALL_PR_MSR, 1, msr) | |
72 | ||
73 | /* | |
74 | * KVM paravirtual msrs to test. Expect a #GP if any of these msrs are read or | |
75 | * written, as the KVM_CPUID_FEATURES leaf is cleared. | |
76 | */ | |
77 | static struct msr_data msrs_to_test[] = { | |
78 | TEST_MSR(MSR_KVM_SYSTEM_TIME), | |
79 | TEST_MSR(MSR_KVM_SYSTEM_TIME_NEW), | |
80 | TEST_MSR(MSR_KVM_WALL_CLOCK), | |
81 | TEST_MSR(MSR_KVM_WALL_CLOCK_NEW), | |
82 | TEST_MSR(MSR_KVM_ASYNC_PF_EN), | |
83 | TEST_MSR(MSR_KVM_STEAL_TIME), | |
84 | TEST_MSR(MSR_KVM_PV_EOI_EN), | |
85 | TEST_MSR(MSR_KVM_POLL_CONTROL), | |
86 | TEST_MSR(MSR_KVM_ASYNC_PF_INT), | |
87 | TEST_MSR(MSR_KVM_ASYNC_PF_ACK), | |
88 | }; | |
89 | ||
90 | static void test_msr(struct msr_data *msr) | |
91 | { | |
92 | PR_MSR(msr); | |
93 | do_rdmsr(msr->idx); | |
94 | GUEST_ASSERT(READ_ONCE(nr_gp) == 1); | |
95 | ||
96 | nr_gp = 0; | |
97 | do_wrmsr(msr->idx, 0); | |
98 | GUEST_ASSERT(READ_ONCE(nr_gp) == 1); | |
99 | nr_gp = 0; | |
100 | } | |
101 | ||
102 | struct hcall_data { | |
103 | uint64_t nr; | |
104 | const char *name; | |
105 | }; | |
106 | ||
107 | #define TEST_HCALL(hc) { .nr = hc, .name = #hc } | |
108 | #define UCALL_PR_HCALL 0xdeadc0de | |
109 | #define PR_HCALL(hc) ucall(UCALL_PR_HCALL, 1, hc) | |
110 | ||
111 | /* | |
112 | * KVM hypercalls to test. Expect -KVM_ENOSYS when called, as the corresponding | |
113 | * features have been cleared in KVM_CPUID_FEATURES. | |
114 | */ | |
115 | static struct hcall_data hcalls_to_test[] = { | |
116 | TEST_HCALL(KVM_HC_KICK_CPU), | |
117 | TEST_HCALL(KVM_HC_SEND_IPI), | |
118 | TEST_HCALL(KVM_HC_SCHED_YIELD), | |
119 | }; | |
120 | ||
121 | static void test_hcall(struct hcall_data *hc) | |
122 | { | |
123 | uint64_t r; | |
124 | ||
125 | PR_HCALL(hc); | |
126 | r = kvm_hypercall(hc->nr, 0, 0, 0, 0); | |
127 | GUEST_ASSERT(r == -KVM_ENOSYS); | |
128 | } | |
129 | ||
130 | static void guest_main(void) | |
131 | { | |
132 | int i; | |
133 | ||
134 | for (i = 0; i < ARRAY_SIZE(msrs_to_test); i++) { | |
135 | test_msr(&msrs_to_test[i]); | |
136 | } | |
137 | ||
138 | for (i = 0; i < ARRAY_SIZE(hcalls_to_test); i++) { | |
139 | test_hcall(&hcalls_to_test[i]); | |
140 | } | |
141 | ||
142 | GUEST_DONE(); | |
143 | } | |
144 | ||
145 | static void clear_kvm_cpuid_features(struct kvm_cpuid2 *cpuid) | |
146 | { | |
147 | struct kvm_cpuid_entry2 ent = {0}; | |
148 | ||
149 | ent.function = KVM_CPUID_FEATURES; | |
150 | TEST_ASSERT(set_cpuid(cpuid, &ent), | |
151 | "failed to clear KVM_CPUID_FEATURES leaf"); | |
152 | } | |
153 | ||
154 | static void pr_msr(struct ucall *uc) | |
155 | { | |
156 | struct msr_data *msr = (struct msr_data *)uc->args[0]; | |
157 | ||
158 | pr_info("testing msr: %s (%#x)\n", msr->name, msr->idx); | |
159 | } | |
160 | ||
161 | static void pr_hcall(struct ucall *uc) | |
162 | { | |
163 | struct hcall_data *hc = (struct hcall_data *)uc->args[0]; | |
164 | ||
165 | pr_info("testing hcall: %s (%lu)\n", hc->name, hc->nr); | |
166 | } | |
167 | ||
168 | static void handle_abort(struct ucall *uc) | |
169 | { | |
170 | TEST_FAIL("%s at %s:%ld", (const char *)uc->args[0], | |
171 | __FILE__, uc->args[1]); | |
172 | } | |
173 | ||
f323dbce | 174 | static void enter_guest(struct kvm_vcpu *vcpu) |
ac4a4d6d | 175 | { |
f323dbce | 176 | struct kvm_run *run = vcpu->run; |
ac4a4d6d | 177 | struct ucall uc; |
ac4a4d6d OU |
178 | |
179 | while (true) { | |
f323dbce | 180 | vcpu_run(vcpu->vm, vcpu->id); |
ac4a4d6d OU |
181 | TEST_ASSERT(run->exit_reason == KVM_EXIT_IO, |
182 | "unexpected exit reason: %u (%s)", | |
183 | run->exit_reason, exit_reason_str(run->exit_reason)); | |
184 | ||
f323dbce | 185 | switch (get_ucall(vcpu->vm, vcpu->id, &uc)) { |
ac4a4d6d OU |
186 | case UCALL_PR_MSR: |
187 | pr_msr(&uc); | |
188 | break; | |
189 | case UCALL_PR_HCALL: | |
190 | pr_hcall(&uc); | |
191 | break; | |
192 | case UCALL_ABORT: | |
193 | handle_abort(&uc); | |
194 | return; | |
195 | case UCALL_DONE: | |
196 | return; | |
197 | } | |
198 | } | |
199 | } | |
200 | ||
201 | int main(void) | |
202 | { | |
ac4a4d6d | 203 | struct kvm_cpuid2 *best; |
f323dbce | 204 | struct kvm_vcpu *vcpu; |
ac4a4d6d OU |
205 | struct kvm_vm *vm; |
206 | ||
207 | if (!kvm_check_cap(KVM_CAP_ENFORCE_PV_FEATURE_CPUID)) { | |
08d3e277 AJ |
208 | print_skip("KVM_CAP_ENFORCE_PV_FEATURE_CPUID not supported"); |
209 | exit(KSFT_SKIP); | |
ac4a4d6d OU |
210 | } |
211 | ||
f323dbce | 212 | vm = vm_create_with_one_vcpu(&vcpu, guest_main); |
ac4a4d6d | 213 | |
f323dbce | 214 | vcpu_enable_cap(vm, vcpu->id, KVM_CAP_ENFORCE_PV_FEATURE_CPUID, 1); |
ac4a4d6d OU |
215 | |
216 | best = kvm_get_supported_cpuid(); | |
217 | clear_kvm_cpuid_features(best); | |
f323dbce | 218 | vcpu_set_cpuid(vm, vcpu->id, best); |
ac4a4d6d OU |
219 | |
220 | vm_init_descriptor_tables(vm); | |
f323dbce | 221 | vcpu_init_descriptor_tables(vm, vcpu->id); |
b78f4a59 | 222 | vm_install_exception_handler(vm, GP_VECTOR, guest_gp_handler); |
ac4a4d6d | 223 | |
f323dbce | 224 | enter_guest(vcpu); |
ac4a4d6d OU |
225 | kvm_vm_free(vm); |
226 | } |