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
15struct msr_data {
16	uint32_t idx;
17	const char *name;
18};
19
20#define TEST_MSR(msr) { .idx = msr, .name = #msr }
21#define UCALL_PR_MSR 0xdeadbeef
22#define PR_MSR(msr) ucall(UCALL_PR_MSR, 1, msr)
23
24/*
25 * KVM paravirtual msrs to test. Expect a #GP if any of these msrs are read or
26 * written, as the KVM_CPUID_FEATURES leaf is cleared.
27 */
28static struct msr_data msrs_to_test[] = {
29	TEST_MSR(MSR_KVM_SYSTEM_TIME),
30	TEST_MSR(MSR_KVM_SYSTEM_TIME_NEW),
31	TEST_MSR(MSR_KVM_WALL_CLOCK),
32	TEST_MSR(MSR_KVM_WALL_CLOCK_NEW),
33	TEST_MSR(MSR_KVM_ASYNC_PF_EN),
34	TEST_MSR(MSR_KVM_STEAL_TIME),
35	TEST_MSR(MSR_KVM_PV_EOI_EN),
36	TEST_MSR(MSR_KVM_POLL_CONTROL),
37	TEST_MSR(MSR_KVM_ASYNC_PF_INT),
38	TEST_MSR(MSR_KVM_ASYNC_PF_ACK),
39};
40
41static void test_msr(struct msr_data *msr)
42{
43	uint64_t ignored;
44	uint8_t vector;
45
46	PR_MSR(msr);
47
48	vector = rdmsr_safe(msr->idx, &ignored);
49	GUEST_ASSERT_EQ(vector, GP_VECTOR);
50
51	vector = wrmsr_safe(msr->idx, 0);
52	GUEST_ASSERT_EQ(vector, GP_VECTOR);
53}
54
55struct hcall_data {
56	uint64_t nr;
57	const char *name;
58};
59
60#define TEST_HCALL(hc) { .nr = hc, .name = #hc }
61#define UCALL_PR_HCALL 0xdeadc0de
62#define PR_HCALL(hc) ucall(UCALL_PR_HCALL, 1, hc)
63
64/*
65 * KVM hypercalls to test. Expect -KVM_ENOSYS when called, as the corresponding
66 * features have been cleared in KVM_CPUID_FEATURES.
67 */
68static struct hcall_data hcalls_to_test[] = {
69	TEST_HCALL(KVM_HC_KICK_CPU),
70	TEST_HCALL(KVM_HC_SEND_IPI),
71	TEST_HCALL(KVM_HC_SCHED_YIELD),
72};
73
74static void test_hcall(struct hcall_data *hc)
75{
76	uint64_t r;
77
78	PR_HCALL(hc);
79	r = kvm_hypercall(hc->nr, 0, 0, 0, 0);
80	GUEST_ASSERT_EQ(r, -KVM_ENOSYS);
81}
82
83static void guest_main(void)
84{
85	int i;
86
87	for (i = 0; i < ARRAY_SIZE(msrs_to_test); i++) {
88		test_msr(&msrs_to_test[i]);
89	}
90
91	for (i = 0; i < ARRAY_SIZE(hcalls_to_test); i++) {
92		test_hcall(&hcalls_to_test[i]);
93	}
94
95	GUEST_DONE();
96}
97
98static void pr_msr(struct ucall *uc)
99{
100	struct msr_data *msr = (struct msr_data *)uc->args[0];
101
102	pr_info("testing msr: %s (%#x)\n", msr->name, msr->idx);
103}
104
105static void pr_hcall(struct ucall *uc)
106{
107	struct hcall_data *hc = (struct hcall_data *)uc->args[0];
108
109	pr_info("testing hcall: %s (%lu)\n", hc->name, hc->nr);
110}
111
112static void enter_guest(struct kvm_vcpu *vcpu)
113{
114	struct ucall uc;
115
116	while (true) {
117		vcpu_run(vcpu);
118		TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
119
120		switch (get_ucall(vcpu, &uc)) {
121		case UCALL_PR_MSR:
122			pr_msr(&uc);
123			break;
124		case UCALL_PR_HCALL:
125			pr_hcall(&uc);
126			break;
127		case UCALL_ABORT:
128			REPORT_GUEST_ASSERT(uc);
129			return;
130		case UCALL_DONE:
131			return;
132		}
133	}
134}
135
136static void test_pv_unhalt(void)
137{
138	struct kvm_vcpu *vcpu;
139	struct kvm_vm *vm;
140	struct kvm_cpuid_entry2 *ent;
141	u32 kvm_sig_old;
142
143	pr_info("testing KVM_FEATURE_PV_UNHALT\n");
144
145	TEST_REQUIRE(KVM_CAP_X86_DISABLE_EXITS);
146
147	/* KVM_PV_UNHALT test */
148	vm = vm_create_with_one_vcpu(&vcpu, guest_main);
149	vcpu_set_cpuid_feature(vcpu, X86_FEATURE_KVM_PV_UNHALT);
150
151	TEST_ASSERT(vcpu_cpuid_has(vcpu, X86_FEATURE_KVM_PV_UNHALT),
152		    "Enabling X86_FEATURE_KVM_PV_UNHALT had no effect");
153
154	/* Make sure KVM clears vcpu->arch.kvm_cpuid */
155	ent = vcpu_get_cpuid_entry(vcpu, KVM_CPUID_SIGNATURE);
156	kvm_sig_old = ent->ebx;
157	ent->ebx = 0xdeadbeef;
158	vcpu_set_cpuid(vcpu);
159
160	vm_enable_cap(vm, KVM_CAP_X86_DISABLE_EXITS, KVM_X86_DISABLE_EXITS_HLT);
161	ent = vcpu_get_cpuid_entry(vcpu, KVM_CPUID_SIGNATURE);
162	ent->ebx = kvm_sig_old;
163	vcpu_set_cpuid(vcpu);
164
165	TEST_ASSERT(!vcpu_cpuid_has(vcpu, X86_FEATURE_KVM_PV_UNHALT),
166		    "KVM_FEATURE_PV_UNHALT is set with KVM_CAP_X86_DISABLE_EXITS");
167
168	/* FIXME: actually test KVM_FEATURE_PV_UNHALT feature */
169
170	kvm_vm_free(vm);
171}
172
173int main(void)
174{
175	struct kvm_vcpu *vcpu;
176	struct kvm_vm *vm;
177
178	TEST_REQUIRE(kvm_has_cap(KVM_CAP_ENFORCE_PV_FEATURE_CPUID));
179
180	vm = vm_create_with_one_vcpu(&vcpu, guest_main);
181
182	vcpu_enable_cap(vcpu, KVM_CAP_ENFORCE_PV_FEATURE_CPUID, 1);
183
184	vcpu_clear_cpuid_entry(vcpu, KVM_CPUID_FEATURES);
185
186	vm_init_descriptor_tables(vm);
187	vcpu_init_descriptor_tables(vcpu);
188
189	enter_guest(vcpu);
190	kvm_vm_free(vm);
191
192	test_pv_unhalt();
193}
194