1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2021, Google LLC.
4  *
5  * Tests for adjusting the KVM clock from userspace
6  */
7 #include <asm/kvm_para.h>
8 #include <asm/pvclock.h>
9 #include <asm/pvclock-abi.h>
10 #include <stdint.h>
11 #include <string.h>
12 #include <sys/stat.h>
13 #include <time.h>
14 
15 #include "test_util.h"
16 #include "kvm_util.h"
17 #include "processor.h"
18 
19 struct test_case {
20 	uint64_t kvmclock_base;
21 	int64_t realtime_offset;
22 };
23 
24 static struct test_case test_cases[] = {
25 	{ .kvmclock_base = 0 },
26 	{ .kvmclock_base = 180 * NSEC_PER_SEC },
27 	{ .kvmclock_base = 0, .realtime_offset = -180 * NSEC_PER_SEC },
28 	{ .kvmclock_base = 0, .realtime_offset = 180 * NSEC_PER_SEC },
29 };
30 
31 #define GUEST_SYNC_CLOCK(__stage, __val)			\
32 		GUEST_SYNC_ARGS(__stage, __val, 0, 0, 0)
33 
guest_main(vm_paddr_t pvti_pa,struct pvclock_vcpu_time_info * pvti)34 static void guest_main(vm_paddr_t pvti_pa, struct pvclock_vcpu_time_info *pvti)
35 {
36 	int i;
37 
38 	wrmsr(MSR_KVM_SYSTEM_TIME_NEW, pvti_pa | KVM_MSR_ENABLED);
39 	for (i = 0; i < ARRAY_SIZE(test_cases); i++)
40 		GUEST_SYNC_CLOCK(i, __pvclock_read_cycles(pvti, rdtsc()));
41 }
42 
43 #define EXPECTED_FLAGS (KVM_CLOCK_REALTIME | KVM_CLOCK_HOST_TSC)
44 
assert_flags(struct kvm_clock_data * data)45 static inline void assert_flags(struct kvm_clock_data *data)
46 {
47 	TEST_ASSERT((data->flags & EXPECTED_FLAGS) == EXPECTED_FLAGS,
48 		    "unexpected clock data flags: %x (want set: %x)",
49 		    data->flags, EXPECTED_FLAGS);
50 }
51 
handle_sync(struct ucall * uc,struct kvm_clock_data * start,struct kvm_clock_data * end)52 static void handle_sync(struct ucall *uc, struct kvm_clock_data *start,
53 			struct kvm_clock_data *end)
54 {
55 	uint64_t obs, exp_lo, exp_hi;
56 
57 	obs = uc->args[2];
58 	exp_lo = start->clock;
59 	exp_hi = end->clock;
60 
61 	assert_flags(start);
62 	assert_flags(end);
63 
64 	TEST_ASSERT(exp_lo <= obs && obs <= exp_hi,
65 		    "unexpected kvm-clock value: %"PRIu64" expected range: [%"PRIu64", %"PRIu64"]",
66 		    obs, exp_lo, exp_hi);
67 
68 	pr_info("kvm-clock value: %"PRIu64" expected range [%"PRIu64", %"PRIu64"]\n",
69 		obs, exp_lo, exp_hi);
70 }
71 
handle_abort(struct ucall * uc)72 static void handle_abort(struct ucall *uc)
73 {
74 	REPORT_GUEST_ASSERT(*uc);
75 }
76 
setup_clock(struct kvm_vm * vm,struct test_case * test_case)77 static void setup_clock(struct kvm_vm *vm, struct test_case *test_case)
78 {
79 	struct kvm_clock_data data;
80 
81 	memset(&data, 0, sizeof(data));
82 
83 	data.clock = test_case->kvmclock_base;
84 	if (test_case->realtime_offset) {
85 		struct timespec ts;
86 		int r;
87 
88 		data.flags |= KVM_CLOCK_REALTIME;
89 		do {
90 			r = clock_gettime(CLOCK_REALTIME, &ts);
91 			if (!r)
92 				break;
93 		} while (errno == EINTR);
94 
95 		TEST_ASSERT(!r, "clock_gettime() failed: %d\n", r);
96 
97 		data.realtime = ts.tv_sec * NSEC_PER_SEC;
98 		data.realtime += ts.tv_nsec;
99 		data.realtime += test_case->realtime_offset;
100 	}
101 
102 	vm_ioctl(vm, KVM_SET_CLOCK, &data);
103 }
104 
enter_guest(struct kvm_vcpu * vcpu)105 static void enter_guest(struct kvm_vcpu *vcpu)
106 {
107 	struct kvm_clock_data start, end;
108 	struct kvm_vm *vm = vcpu->vm;
109 	struct ucall uc;
110 	int i;
111 
112 	for (i = 0; i < ARRAY_SIZE(test_cases); i++) {
113 		setup_clock(vm, &test_cases[i]);
114 
115 		vm_ioctl(vm, KVM_GET_CLOCK, &start);
116 
117 		vcpu_run(vcpu);
118 		vm_ioctl(vm, KVM_GET_CLOCK, &end);
119 
120 		TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
121 
122 		switch (get_ucall(vcpu, &uc)) {
123 		case UCALL_SYNC:
124 			handle_sync(&uc, &start, &end);
125 			break;
126 		case UCALL_ABORT:
127 			handle_abort(&uc);
128 			return;
129 		default:
130 			TEST_ASSERT(0, "unhandled ucall: %ld\n", uc.cmd);
131 		}
132 	}
133 }
134 
135 #define CLOCKSOURCE_PATH "/sys/devices/system/clocksource/clocksource0/current_clocksource"
136 
check_clocksource(void)137 static void check_clocksource(void)
138 {
139 	char *clk_name;
140 	struct stat st;
141 	FILE *fp;
142 
143 	fp = fopen(CLOCKSOURCE_PATH, "r");
144 	if (!fp) {
145 		pr_info("failed to open clocksource file: %d; assuming TSC.\n",
146 			errno);
147 		return;
148 	}
149 
150 	if (fstat(fileno(fp), &st)) {
151 		pr_info("failed to stat clocksource file: %d; assuming TSC.\n",
152 			errno);
153 		goto out;
154 	}
155 
156 	clk_name = malloc(st.st_size);
157 	TEST_ASSERT(clk_name, "failed to allocate buffer to read file\n");
158 
159 	if (!fgets(clk_name, st.st_size, fp)) {
160 		pr_info("failed to read clocksource file: %d; assuming TSC.\n",
161 			ferror(fp));
162 		goto out;
163 	}
164 
165 	TEST_ASSERT(!strncmp(clk_name, "tsc\n", st.st_size),
166 		    "clocksource not supported: %s", clk_name);
167 out:
168 	fclose(fp);
169 }
170 
main(void)171 int main(void)
172 {
173 	struct kvm_vcpu *vcpu;
174 	vm_vaddr_t pvti_gva;
175 	vm_paddr_t pvti_gpa;
176 	struct kvm_vm *vm;
177 	int flags;
178 
179 	flags = kvm_check_cap(KVM_CAP_ADJUST_CLOCK);
180 	TEST_REQUIRE(flags & KVM_CLOCK_REALTIME);
181 
182 	check_clocksource();
183 
184 	vm = vm_create_with_one_vcpu(&vcpu, guest_main);
185 
186 	pvti_gva = vm_vaddr_alloc(vm, getpagesize(), 0x10000);
187 	pvti_gpa = addr_gva2gpa(vm, pvti_gva);
188 	vcpu_args_set(vcpu, 2, pvti_gpa, pvti_gva);
189 
190 	enter_guest(vcpu);
191 	kvm_vm_free(vm);
192 }
193