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 int hv_setup_vmbus_irq(int irq, void (*handler)(void)) 59 { 60 /* 61 * The 'irq' argument is ignored on x86/x64 because a hard-coded 62 * interrupt vector is used for Hyper-V interrupts. 63 */ 64 vmbus_handler = handler; 65 return 0; 66 } 67 68 void hv_remove_vmbus_irq(void) 69 { 70 /* We have no way to deallocate the interrupt gate */ 71 vmbus_handler = NULL; 72 } 73 EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq); 74 EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq); 75 76 /* 77 * Routines to do per-architecture handling of stimer0 78 * interrupts when in Direct Mode 79 */ 80 DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_stimer0) 81 { 82 struct pt_regs *old_regs = set_irq_regs(regs); 83 84 inc_irq_stat(hyperv_stimer0_count); 85 if (hv_stimer0_handler) 86 hv_stimer0_handler(); 87 add_interrupt_randomness(HYPERV_STIMER0_VECTOR, 0); 88 ack_APIC_irq(); 89 90 set_irq_regs(old_regs); 91 } 92 93 int hv_setup_stimer0_irq(int *irq, int *vector, void (*handler)(void)) 94 { 95 *vector = HYPERV_STIMER0_VECTOR; 96 *irq = -1; /* Unused on x86/x64 */ 97 hv_stimer0_handler = handler; 98 return 0; 99 } 100 EXPORT_SYMBOL_GPL(hv_setup_stimer0_irq); 101 102 void hv_remove_stimer0_irq(int irq) 103 { 104 /* We have no way to deallocate the interrupt gate */ 105 hv_stimer0_handler = NULL; 106 } 107 EXPORT_SYMBOL_GPL(hv_remove_stimer0_irq); 108 109 void hv_setup_kexec_handler(void (*handler)(void)) 110 { 111 hv_kexec_handler = handler; 112 } 113 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler); 114 115 void hv_remove_kexec_handler(void) 116 { 117 hv_kexec_handler = NULL; 118 } 119 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler); 120 121 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs)) 122 { 123 hv_crash_handler = handler; 124 } 125 EXPORT_SYMBOL_GPL(hv_setup_crash_handler); 126 127 void hv_remove_crash_handler(void) 128 { 129 hv_crash_handler = NULL; 130 } 131 EXPORT_SYMBOL_GPL(hv_remove_crash_handler); 132 133 #ifdef CONFIG_KEXEC_CORE 134 static void hv_machine_shutdown(void) 135 { 136 if (kexec_in_progress && hv_kexec_handler) 137 hv_kexec_handler(); 138 native_machine_shutdown(); 139 } 140 141 static void hv_machine_crash_shutdown(struct pt_regs *regs) 142 { 143 if (hv_crash_handler) 144 hv_crash_handler(regs); 145 native_machine_crash_shutdown(regs); 146 } 147 #endif /* CONFIG_KEXEC_CORE */ 148 #endif /* CONFIG_HYPERV */ 149 150 static uint32_t __init ms_hyperv_platform(void) 151 { 152 u32 eax; 153 u32 hyp_signature[3]; 154 155 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) 156 return 0; 157 158 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS, 159 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]); 160 161 if (eax >= HYPERV_CPUID_MIN && 162 eax <= HYPERV_CPUID_MAX && 163 !memcmp("Microsoft Hv", hyp_signature, 12)) 164 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS; 165 166 return 0; 167 } 168 169 static unsigned char hv_get_nmi_reason(void) 170 { 171 return 0; 172 } 173 174 #ifdef CONFIG_X86_LOCAL_APIC 175 /* 176 * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes 177 * it dificult to process CHANNELMSG_UNLOAD in case of crash. Handle 178 * unknown NMI on the first CPU which gets it. 179 */ 180 static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs) 181 { 182 static atomic_t nmi_cpu = ATOMIC_INIT(-1); 183 184 if (!unknown_nmi_panic) 185 return NMI_DONE; 186 187 if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1) 188 return NMI_HANDLED; 189 190 return NMI_DONE; 191 } 192 #endif 193 194 static unsigned long hv_get_tsc_khz(void) 195 { 196 unsigned long freq; 197 198 rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq); 199 200 return freq / 1000; 201 } 202 203 #if defined(CONFIG_SMP) && IS_ENABLED(CONFIG_HYPERV) 204 static void __init hv_smp_prepare_boot_cpu(void) 205 { 206 native_smp_prepare_boot_cpu(); 207 #if defined(CONFIG_X86_64) && defined(CONFIG_PARAVIRT_SPINLOCKS) 208 hv_init_spinlocks(); 209 #endif 210 } 211 #endif 212 213 static void __init ms_hyperv_init_platform(void) 214 { 215 int hv_host_info_eax; 216 int hv_host_info_ebx; 217 int hv_host_info_ecx; 218 int hv_host_info_edx; 219 220 #ifdef CONFIG_PARAVIRT 221 pv_info.name = "Hyper-V"; 222 #endif 223 224 /* 225 * Extract the features and hints 226 */ 227 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES); 228 ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES); 229 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO); 230 231 pr_info("Hyper-V: features 0x%x, hints 0x%x, misc 0x%x\n", 232 ms_hyperv.features, ms_hyperv.hints, ms_hyperv.misc_features); 233 234 ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS); 235 ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS); 236 237 pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n", 238 ms_hyperv.max_vp_index, ms_hyperv.max_lp_index); 239 240 /* 241 * Extract host information. 242 */ 243 if (cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS) >= 244 HYPERV_CPUID_VERSION) { 245 hv_host_info_eax = cpuid_eax(HYPERV_CPUID_VERSION); 246 hv_host_info_ebx = cpuid_ebx(HYPERV_CPUID_VERSION); 247 hv_host_info_ecx = cpuid_ecx(HYPERV_CPUID_VERSION); 248 hv_host_info_edx = cpuid_edx(HYPERV_CPUID_VERSION); 249 250 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n", 251 hv_host_info_eax, hv_host_info_ebx >> 16, 252 hv_host_info_ebx & 0xFFFF, hv_host_info_ecx, 253 hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF); 254 } 255 256 if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS && 257 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { 258 x86_platform.calibrate_tsc = hv_get_tsc_khz; 259 x86_platform.calibrate_cpu = hv_get_tsc_khz; 260 } 261 262 if (ms_hyperv.hints & HV_X64_ENLIGHTENED_VMCS_RECOMMENDED) { 263 ms_hyperv.nested_features = 264 cpuid_eax(HYPERV_CPUID_NESTED_FEATURES); 265 } 266 267 /* 268 * Hyper-V expects to get crash register data or kmsg when 269 * crash enlightment is available and system crashes. Set 270 * crash_kexec_post_notifiers to be true to make sure that 271 * calling crash enlightment interface before running kdump 272 * kernel. 273 */ 274 if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) 275 crash_kexec_post_notifiers = true; 276 277 #ifdef CONFIG_X86_LOCAL_APIC 278 if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS && 279 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { 280 /* 281 * Get the APIC frequency. 282 */ 283 u64 hv_lapic_frequency; 284 285 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency); 286 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ); 287 lapic_timer_period = hv_lapic_frequency; 288 pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n", 289 lapic_timer_period); 290 } 291 292 register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST, 293 "hv_nmi_unknown"); 294 #endif 295 296 #ifdef CONFIG_X86_IO_APIC 297 no_timer_check = 1; 298 #endif 299 300 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE) 301 machine_ops.shutdown = hv_machine_shutdown; 302 machine_ops.crash_shutdown = hv_machine_crash_shutdown; 303 #endif 304 if (ms_hyperv.features & HV_ACCESS_TSC_INVARIANT) { 305 wrmsrl(HV_X64_MSR_TSC_INVARIANT_CONTROL, 0x1); 306 setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE); 307 } else { 308 mark_tsc_unstable("running on Hyper-V"); 309 } 310 311 /* 312 * Generation 2 instances don't support reading the NMI status from 313 * 0x61 port. 314 */ 315 if (efi_enabled(EFI_BOOT)) 316 x86_platform.get_nmi_reason = hv_get_nmi_reason; 317 318 /* 319 * Hyper-V VMs have a PIT emulation quirk such that zeroing the 320 * counter register during PIT shutdown restarts the PIT. So it 321 * continues to interrupt @18.2 HZ. Setting i8253_clear_counter 322 * to false tells pit_shutdown() not to zero the counter so that 323 * the PIT really is shutdown. Generation 2 VMs don't have a PIT, 324 * and setting this value has no effect. 325 */ 326 i8253_clear_counter_on_shutdown = false; 327 328 #if IS_ENABLED(CONFIG_HYPERV) 329 /* 330 * Setup the hook to get control post apic initialization. 331 */ 332 x86_platform.apic_post_init = hyperv_init; 333 hyperv_setup_mmu_ops(); 334 /* Setup the IDT for hypervisor callback */ 335 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_hyperv_callback); 336 337 /* Setup the IDT for reenlightenment notifications */ 338 if (ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT) { 339 alloc_intr_gate(HYPERV_REENLIGHTENMENT_VECTOR, 340 asm_sysvec_hyperv_reenlightenment); 341 } 342 343 /* Setup the IDT for stimer0 */ 344 if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE) { 345 alloc_intr_gate(HYPERV_STIMER0_VECTOR, 346 asm_sysvec_hyperv_stimer0); 347 } 348 349 # ifdef CONFIG_SMP 350 smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu; 351 # endif 352 353 /* 354 * Hyper-V doesn't provide irq remapping for IO-APIC. To enable x2apic, 355 * set x2apic destination mode to physcial mode when x2apic is available 356 * and Hyper-V IOMMU driver makes sure cpus assigned with IO-APIC irqs 357 * have 8-bit APIC id. 358 */ 359 # ifdef CONFIG_X86_X2APIC 360 if (x2apic_supported()) 361 x2apic_phys = 1; 362 # endif 363 364 /* Register Hyper-V specific clocksource */ 365 hv_init_clocksource(); 366 #endif 367 } 368 369 const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = { 370 .name = "Microsoft Hyper-V", 371 .detect = ms_hyperv_platform, 372 .type = X86_HYPER_MS_HYPERV, 373 .init.init_platform = ms_hyperv_init_platform, 374 }; 375