1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * HyperV Detection code. 4 * 5 * Copyright (C) 2010, Novell, Inc. 6 * Author : K. Y. Srinivasan <ksrinivasan@novell.com> 7 */ 8 9 #include <linux/types.h> 10 #include <linux/time.h> 11 #include <linux/clocksource.h> 12 #include <linux/init.h> 13 #include <linux/export.h> 14 #include <linux/hardirq.h> 15 #include <linux/efi.h> 16 #include <linux/interrupt.h> 17 #include <linux/irq.h> 18 #include <linux/kexec.h> 19 #include <linux/i8253.h> 20 #include <linux/random.h> 21 #include <asm/processor.h> 22 #include <asm/hypervisor.h> 23 #include <asm/hyperv-tlfs.h> 24 #include <asm/mshyperv.h> 25 #include <asm/desc.h> 26 #include <asm/idtentry.h> 27 #include <asm/irq_regs.h> 28 #include <asm/i8259.h> 29 #include <asm/apic.h> 30 #include <asm/timer.h> 31 #include <asm/reboot.h> 32 #include <asm/nmi.h> 33 #include <clocksource/hyperv_timer.h> 34 35 struct ms_hyperv_info ms_hyperv; 36 EXPORT_SYMBOL_GPL(ms_hyperv); 37 38 #if IS_ENABLED(CONFIG_HYPERV) 39 static void (*vmbus_handler)(void); 40 static void (*hv_stimer0_handler)(void); 41 static void (*hv_kexec_handler)(void); 42 static void (*hv_crash_handler)(struct pt_regs *regs); 43 44 DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_callback) 45 { 46 struct pt_regs *old_regs = set_irq_regs(regs); 47 48 inc_irq_stat(irq_hv_callback_count); 49 if (vmbus_handler) 50 vmbus_handler(); 51 52 if (ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED) 53 ack_APIC_irq(); 54 55 set_irq_regs(old_regs); 56 } 57 58 void hv_setup_vmbus_irq(void (*handler)(void)) 59 { 60 vmbus_handler = handler; 61 } 62 63 void hv_remove_vmbus_irq(void) 64 { 65 /* We have no way to deallocate the interrupt gate */ 66 vmbus_handler = NULL; 67 } 68 EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq); 69 EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq); 70 71 /* 72 * Routines to do per-architecture handling of stimer0 73 * interrupts when in Direct Mode 74 */ 75 DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_stimer0) 76 { 77 struct pt_regs *old_regs = set_irq_regs(regs); 78 79 inc_irq_stat(hyperv_stimer0_count); 80 if (hv_stimer0_handler) 81 hv_stimer0_handler(); 82 add_interrupt_randomness(HYPERV_STIMER0_VECTOR, 0); 83 ack_APIC_irq(); 84 85 set_irq_regs(old_regs); 86 } 87 88 int hv_setup_stimer0_irq(int *irq, int *vector, void (*handler)(void)) 89 { 90 *vector = HYPERV_STIMER0_VECTOR; 91 *irq = -1; /* Unused on x86/x64 */ 92 hv_stimer0_handler = handler; 93 return 0; 94 } 95 EXPORT_SYMBOL_GPL(hv_setup_stimer0_irq); 96 97 void hv_remove_stimer0_irq(int irq) 98 { 99 /* We have no way to deallocate the interrupt gate */ 100 hv_stimer0_handler = NULL; 101 } 102 EXPORT_SYMBOL_GPL(hv_remove_stimer0_irq); 103 104 void hv_setup_kexec_handler(void (*handler)(void)) 105 { 106 hv_kexec_handler = handler; 107 } 108 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler); 109 110 void hv_remove_kexec_handler(void) 111 { 112 hv_kexec_handler = NULL; 113 } 114 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler); 115 116 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs)) 117 { 118 hv_crash_handler = handler; 119 } 120 EXPORT_SYMBOL_GPL(hv_setup_crash_handler); 121 122 void hv_remove_crash_handler(void) 123 { 124 hv_crash_handler = NULL; 125 } 126 EXPORT_SYMBOL_GPL(hv_remove_crash_handler); 127 128 #ifdef CONFIG_KEXEC_CORE 129 static void hv_machine_shutdown(void) 130 { 131 if (kexec_in_progress && hv_kexec_handler) 132 hv_kexec_handler(); 133 native_machine_shutdown(); 134 } 135 136 static void hv_machine_crash_shutdown(struct pt_regs *regs) 137 { 138 if (hv_crash_handler) 139 hv_crash_handler(regs); 140 native_machine_crash_shutdown(regs); 141 } 142 #endif /* CONFIG_KEXEC_CORE */ 143 #endif /* CONFIG_HYPERV */ 144 145 static uint32_t __init ms_hyperv_platform(void) 146 { 147 u32 eax; 148 u32 hyp_signature[3]; 149 150 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) 151 return 0; 152 153 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS, 154 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]); 155 156 if (eax >= HYPERV_CPUID_MIN && 157 eax <= HYPERV_CPUID_MAX && 158 !memcmp("Microsoft Hv", hyp_signature, 12)) 159 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS; 160 161 return 0; 162 } 163 164 static unsigned char hv_get_nmi_reason(void) 165 { 166 return 0; 167 } 168 169 #ifdef CONFIG_X86_LOCAL_APIC 170 /* 171 * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes 172 * it dificult to process CHANNELMSG_UNLOAD in case of crash. Handle 173 * unknown NMI on the first CPU which gets it. 174 */ 175 static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs) 176 { 177 static atomic_t nmi_cpu = ATOMIC_INIT(-1); 178 179 if (!unknown_nmi_panic) 180 return NMI_DONE; 181 182 if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1) 183 return NMI_HANDLED; 184 185 return NMI_DONE; 186 } 187 #endif 188 189 static unsigned long hv_get_tsc_khz(void) 190 { 191 unsigned long freq; 192 193 rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq); 194 195 return freq / 1000; 196 } 197 198 #if defined(CONFIG_SMP) && IS_ENABLED(CONFIG_HYPERV) 199 static void __init hv_smp_prepare_boot_cpu(void) 200 { 201 native_smp_prepare_boot_cpu(); 202 #if defined(CONFIG_X86_64) && defined(CONFIG_PARAVIRT_SPINLOCKS) 203 hv_init_spinlocks(); 204 #endif 205 } 206 #endif 207 208 static void __init ms_hyperv_init_platform(void) 209 { 210 int hv_host_info_eax; 211 int hv_host_info_ebx; 212 int hv_host_info_ecx; 213 int hv_host_info_edx; 214 215 #ifdef CONFIG_PARAVIRT 216 pv_info.name = "Hyper-V"; 217 #endif 218 219 /* 220 * Extract the features and hints 221 */ 222 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES); 223 ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES); 224 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO); 225 226 pr_info("Hyper-V: features 0x%x, hints 0x%x, misc 0x%x\n", 227 ms_hyperv.features, ms_hyperv.hints, ms_hyperv.misc_features); 228 229 ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS); 230 ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS); 231 232 pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n", 233 ms_hyperv.max_vp_index, ms_hyperv.max_lp_index); 234 235 /* 236 * Extract host information. 237 */ 238 if (cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS) >= 239 HYPERV_CPUID_VERSION) { 240 hv_host_info_eax = cpuid_eax(HYPERV_CPUID_VERSION); 241 hv_host_info_ebx = cpuid_ebx(HYPERV_CPUID_VERSION); 242 hv_host_info_ecx = cpuid_ecx(HYPERV_CPUID_VERSION); 243 hv_host_info_edx = cpuid_edx(HYPERV_CPUID_VERSION); 244 245 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n", 246 hv_host_info_eax, hv_host_info_ebx >> 16, 247 hv_host_info_ebx & 0xFFFF, hv_host_info_ecx, 248 hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF); 249 } 250 251 if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS && 252 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { 253 x86_platform.calibrate_tsc = hv_get_tsc_khz; 254 x86_platform.calibrate_cpu = hv_get_tsc_khz; 255 } 256 257 if (ms_hyperv.hints & HV_X64_ENLIGHTENED_VMCS_RECOMMENDED) { 258 ms_hyperv.nested_features = 259 cpuid_eax(HYPERV_CPUID_NESTED_FEATURES); 260 } 261 262 /* 263 * Hyper-V expects to get crash register data or kmsg when 264 * crash enlightment is available and system crashes. Set 265 * crash_kexec_post_notifiers to be true to make sure that 266 * calling crash enlightment interface before running kdump 267 * kernel. 268 */ 269 if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) 270 crash_kexec_post_notifiers = true; 271 272 #ifdef CONFIG_X86_LOCAL_APIC 273 if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS && 274 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { 275 /* 276 * Get the APIC frequency. 277 */ 278 u64 hv_lapic_frequency; 279 280 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency); 281 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ); 282 lapic_timer_period = hv_lapic_frequency; 283 pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n", 284 lapic_timer_period); 285 } 286 287 register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST, 288 "hv_nmi_unknown"); 289 #endif 290 291 #ifdef CONFIG_X86_IO_APIC 292 no_timer_check = 1; 293 #endif 294 295 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE) 296 machine_ops.shutdown = hv_machine_shutdown; 297 machine_ops.crash_shutdown = hv_machine_crash_shutdown; 298 #endif 299 if (ms_hyperv.features & HV_X64_ACCESS_TSC_INVARIANT) { 300 wrmsrl(HV_X64_MSR_TSC_INVARIANT_CONTROL, 0x1); 301 setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE); 302 } else { 303 mark_tsc_unstable("running on Hyper-V"); 304 } 305 306 /* 307 * Generation 2 instances don't support reading the NMI status from 308 * 0x61 port. 309 */ 310 if (efi_enabled(EFI_BOOT)) 311 x86_platform.get_nmi_reason = hv_get_nmi_reason; 312 313 /* 314 * Hyper-V VMs have a PIT emulation quirk such that zeroing the 315 * counter register during PIT shutdown restarts the PIT. So it 316 * continues to interrupt @18.2 HZ. Setting i8253_clear_counter 317 * to false tells pit_shutdown() not to zero the counter so that 318 * the PIT really is shutdown. Generation 2 VMs don't have a PIT, 319 * and setting this value has no effect. 320 */ 321 i8253_clear_counter_on_shutdown = false; 322 323 #if IS_ENABLED(CONFIG_HYPERV) 324 /* 325 * Setup the hook to get control post apic initialization. 326 */ 327 x86_platform.apic_post_init = hyperv_init; 328 hyperv_setup_mmu_ops(); 329 /* Setup the IDT for hypervisor callback */ 330 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_hyperv_callback); 331 332 /* Setup the IDT for reenlightenment notifications */ 333 if (ms_hyperv.features & HV_X64_ACCESS_REENLIGHTENMENT) { 334 alloc_intr_gate(HYPERV_REENLIGHTENMENT_VECTOR, 335 asm_sysvec_hyperv_reenlightenment); 336 } 337 338 /* Setup the IDT for stimer0 */ 339 if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE) { 340 alloc_intr_gate(HYPERV_STIMER0_VECTOR, 341 asm_sysvec_hyperv_stimer0); 342 } 343 344 # ifdef CONFIG_SMP 345 smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu; 346 # endif 347 348 /* 349 * Hyper-V doesn't provide irq remapping for IO-APIC. To enable x2apic, 350 * set x2apic destination mode to physcial mode when x2apic is available 351 * and Hyper-V IOMMU driver makes sure cpus assigned with IO-APIC irqs 352 * have 8-bit APIC id. 353 */ 354 # ifdef CONFIG_X86_X2APIC 355 if (x2apic_supported()) 356 x2apic_phys = 1; 357 # endif 358 359 /* Register Hyper-V specific clocksource */ 360 hv_init_clocksource(); 361 #endif 362 } 363 364 const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = { 365 .name = "Microsoft Hyper-V", 366 .detect = ms_hyperv_platform, 367 .type = X86_HYPER_MS_HYPERV, 368 .init.init_platform = ms_hyperv_init_platform, 369 }; 370