1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 2021, Red Hat, Inc. 4 * 5 * Tests for Hyper-V clocksources 6 */ 7 #include "test_util.h" 8 #include "kvm_util.h" 9 #include "processor.h" 10 11 struct ms_hyperv_tsc_page { 12 volatile u32 tsc_sequence; 13 u32 reserved1; 14 volatile u64 tsc_scale; 15 volatile s64 tsc_offset; 16 } __packed; 17 18 #define HV_X64_MSR_GUEST_OS_ID 0x40000000 19 #define HV_X64_MSR_TIME_REF_COUNT 0x40000020 20 #define HV_X64_MSR_REFERENCE_TSC 0x40000021 21 #define HV_X64_MSR_TSC_FREQUENCY 0x40000022 22 #define HV_X64_MSR_REENLIGHTENMENT_CONTROL 0x40000106 23 #define HV_X64_MSR_TSC_EMULATION_CONTROL 0x40000107 24 25 /* Simplified mul_u64_u64_shr() */ 26 static inline u64 mul_u64_u64_shr64(u64 a, u64 b) 27 { 28 union { 29 u64 ll; 30 struct { 31 u32 low, high; 32 } l; 33 } rm, rn, rh, a0, b0; 34 u64 c; 35 36 a0.ll = a; 37 b0.ll = b; 38 39 rm.ll = (u64)a0.l.low * b0.l.high; 40 rn.ll = (u64)a0.l.high * b0.l.low; 41 rh.ll = (u64)a0.l.high * b0.l.high; 42 43 rh.l.low = c = rm.l.high + rn.l.high + rh.l.low; 44 rh.l.high = (c >> 32) + rh.l.high; 45 46 return rh.ll; 47 } 48 49 static inline void nop_loop(void) 50 { 51 int i; 52 53 for (i = 0; i < 1000000; i++) 54 asm volatile("nop"); 55 } 56 57 static inline void check_tsc_msr_rdtsc(void) 58 { 59 u64 tsc_freq, r1, r2, t1, t2; 60 s64 delta_ns; 61 62 tsc_freq = rdmsr(HV_X64_MSR_TSC_FREQUENCY); 63 GUEST_ASSERT(tsc_freq > 0); 64 65 /* First, check MSR-based clocksource */ 66 r1 = rdtsc(); 67 t1 = rdmsr(HV_X64_MSR_TIME_REF_COUNT); 68 nop_loop(); 69 r2 = rdtsc(); 70 t2 = rdmsr(HV_X64_MSR_TIME_REF_COUNT); 71 72 GUEST_ASSERT(r2 > r1 && t2 > t1); 73 74 /* HV_X64_MSR_TIME_REF_COUNT is in 100ns */ 75 delta_ns = ((t2 - t1) * 100) - ((r2 - r1) * 1000000000 / tsc_freq); 76 if (delta_ns < 0) 77 delta_ns = -delta_ns; 78 79 /* 1% tolerance */ 80 GUEST_ASSERT(delta_ns * 100 < (t2 - t1) * 100); 81 } 82 83 static inline void check_tsc_msr_tsc_page(struct ms_hyperv_tsc_page *tsc_page) 84 { 85 u64 r1, r2, t1, t2; 86 87 /* Compare TSC page clocksource with HV_X64_MSR_TIME_REF_COUNT */ 88 t1 = mul_u64_u64_shr64(rdtsc(), tsc_page->tsc_scale) + tsc_page->tsc_offset; 89 r1 = rdmsr(HV_X64_MSR_TIME_REF_COUNT); 90 91 /* 10 ms tolerance */ 92 GUEST_ASSERT(r1 >= t1 && r1 - t1 < 100000); 93 nop_loop(); 94 95 t2 = mul_u64_u64_shr64(rdtsc(), tsc_page->tsc_scale) + tsc_page->tsc_offset; 96 r2 = rdmsr(HV_X64_MSR_TIME_REF_COUNT); 97 GUEST_ASSERT(r2 >= t1 && r2 - t2 < 100000); 98 } 99 100 static void guest_main(struct ms_hyperv_tsc_page *tsc_page, vm_paddr_t tsc_page_gpa) 101 { 102 u64 tsc_scale, tsc_offset; 103 104 /* Set Guest OS id to enable Hyper-V emulation */ 105 GUEST_SYNC(1); 106 wrmsr(HV_X64_MSR_GUEST_OS_ID, (u64)0x8100 << 48); 107 GUEST_SYNC(2); 108 109 check_tsc_msr_rdtsc(); 110 111 GUEST_SYNC(3); 112 113 /* Set up TSC page is disabled state, check that it's clean */ 114 wrmsr(HV_X64_MSR_REFERENCE_TSC, tsc_page_gpa); 115 GUEST_ASSERT(tsc_page->tsc_sequence == 0); 116 GUEST_ASSERT(tsc_page->tsc_scale == 0); 117 GUEST_ASSERT(tsc_page->tsc_offset == 0); 118 119 GUEST_SYNC(4); 120 121 /* Set up TSC page is enabled state */ 122 wrmsr(HV_X64_MSR_REFERENCE_TSC, tsc_page_gpa | 0x1); 123 GUEST_ASSERT(tsc_page->tsc_sequence != 0); 124 125 GUEST_SYNC(5); 126 127 check_tsc_msr_tsc_page(tsc_page); 128 129 GUEST_SYNC(6); 130 131 tsc_offset = tsc_page->tsc_offset; 132 /* Call KVM_SET_CLOCK from userspace, check that TSC page was updated */ 133 GUEST_SYNC(7); 134 GUEST_ASSERT(tsc_page->tsc_offset != tsc_offset); 135 136 nop_loop(); 137 138 /* 139 * Enable Re-enlightenment and check that TSC page stays constant across 140 * KVM_SET_CLOCK. 141 */ 142 wrmsr(HV_X64_MSR_REENLIGHTENMENT_CONTROL, 0x1 << 16 | 0xff); 143 wrmsr(HV_X64_MSR_TSC_EMULATION_CONTROL, 0x1); 144 tsc_offset = tsc_page->tsc_offset; 145 tsc_scale = tsc_page->tsc_scale; 146 GUEST_SYNC(8); 147 GUEST_ASSERT(tsc_page->tsc_offset == tsc_offset); 148 GUEST_ASSERT(tsc_page->tsc_scale == tsc_scale); 149 150 GUEST_SYNC(9); 151 152 check_tsc_msr_tsc_page(tsc_page); 153 154 /* 155 * Disable re-enlightenment and TSC page, check that KVM doesn't update 156 * it anymore. 157 */ 158 wrmsr(HV_X64_MSR_REENLIGHTENMENT_CONTROL, 0); 159 wrmsr(HV_X64_MSR_TSC_EMULATION_CONTROL, 0); 160 wrmsr(HV_X64_MSR_REFERENCE_TSC, 0); 161 memset(tsc_page, 0, sizeof(*tsc_page)); 162 163 GUEST_SYNC(10); 164 GUEST_ASSERT(tsc_page->tsc_sequence == 0); 165 GUEST_ASSERT(tsc_page->tsc_offset == 0); 166 GUEST_ASSERT(tsc_page->tsc_scale == 0); 167 168 GUEST_DONE(); 169 } 170 171 #define VCPU_ID 0 172 173 static void host_check_tsc_msr_rdtsc(struct kvm_vm *vm) 174 { 175 u64 tsc_freq, r1, r2, t1, t2; 176 s64 delta_ns; 177 178 tsc_freq = vcpu_get_msr(vm, VCPU_ID, HV_X64_MSR_TSC_FREQUENCY); 179 TEST_ASSERT(tsc_freq > 0, "TSC frequency must be nonzero"); 180 181 /* First, check MSR-based clocksource */ 182 r1 = rdtsc(); 183 t1 = vcpu_get_msr(vm, VCPU_ID, HV_X64_MSR_TIME_REF_COUNT); 184 nop_loop(); 185 r2 = rdtsc(); 186 t2 = vcpu_get_msr(vm, VCPU_ID, HV_X64_MSR_TIME_REF_COUNT); 187 188 TEST_ASSERT(t2 > t1, "Time reference MSR is not monotonic (%ld <= %ld)", t1, t2); 189 190 /* HV_X64_MSR_TIME_REF_COUNT is in 100ns */ 191 delta_ns = ((t2 - t1) * 100) - ((r2 - r1) * 1000000000 / tsc_freq); 192 if (delta_ns < 0) 193 delta_ns = -delta_ns; 194 195 /* 1% tolerance */ 196 TEST_ASSERT(delta_ns * 100 < (t2 - t1) * 100, 197 "Elapsed time does not match (MSR=%ld, TSC=%ld)", 198 (t2 - t1) * 100, (r2 - r1) * 1000000000 / tsc_freq); 199 } 200 201 int main(void) 202 { 203 struct kvm_vm *vm; 204 struct kvm_run *run; 205 struct ucall uc; 206 vm_vaddr_t tsc_page_gva; 207 int stage; 208 209 vm = vm_create_default(VCPU_ID, 0, guest_main); 210 run = vcpu_state(vm, VCPU_ID); 211 212 vcpu_set_hv_cpuid(vm, VCPU_ID); 213 214 tsc_page_gva = vm_vaddr_alloc(vm, getpagesize(), 0x10000, 0, 0); 215 memset(addr_gpa2hva(vm, tsc_page_gva), 0x0, getpagesize()); 216 TEST_ASSERT((addr_gva2gpa(vm, tsc_page_gva) & (getpagesize() - 1)) == 0, 217 "TSC page has to be page aligned\n"); 218 vcpu_args_set(vm, VCPU_ID, 2, tsc_page_gva, addr_gva2gpa(vm, tsc_page_gva)); 219 220 host_check_tsc_msr_rdtsc(vm); 221 222 for (stage = 1;; stage++) { 223 _vcpu_run(vm, VCPU_ID); 224 TEST_ASSERT(run->exit_reason == KVM_EXIT_IO, 225 "Stage %d: unexpected exit reason: %u (%s),\n", 226 stage, run->exit_reason, 227 exit_reason_str(run->exit_reason)); 228 229 switch (get_ucall(vm, VCPU_ID, &uc)) { 230 case UCALL_ABORT: 231 TEST_FAIL("%s at %s:%ld", (const char *)uc.args[0], 232 __FILE__, uc.args[1]); 233 /* NOT REACHED */ 234 case UCALL_SYNC: 235 break; 236 case UCALL_DONE: 237 /* Keep in sync with guest_main() */ 238 TEST_ASSERT(stage == 11, "Testing ended prematurely, stage %d\n", 239 stage); 240 goto out; 241 default: 242 TEST_FAIL("Unknown ucall %lu", uc.cmd); 243 } 244 245 TEST_ASSERT(!strcmp((const char *)uc.args[0], "hello") && 246 uc.args[1] == stage, 247 "Stage %d: Unexpected register values vmexit, got %lx", 248 stage, (ulong)uc.args[1]); 249 250 /* Reset kvmclock triggering TSC page update */ 251 if (stage == 7 || stage == 8 || stage == 10) { 252 struct kvm_clock_data clock = {0}; 253 254 vm_ioctl(vm, KVM_SET_CLOCK, &clock); 255 } 256 } 257 258 out: 259 kvm_vm_free(vm); 260 } 261