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/panic_notifier.h> 21 #include <linux/random.h> 22 #include <asm/processor.h> 23 #include <asm/hypervisor.h> 24 #include <asm/hyperv-tlfs.h> 25 #include <asm/mshyperv.h> 26 #include <asm/desc.h> 27 #include <asm/idtentry.h> 28 #include <asm/irq_regs.h> 29 #include <asm/i8259.h> 30 #include <asm/apic.h> 31 #include <asm/timer.h> 32 #include <asm/reboot.h> 33 #include <asm/nmi.h> 34 #include <clocksource/hyperv_timer.h> 35 #include <asm/numa.h> 36 37 /* Is Linux running as the root partition? */ 38 bool hv_root_partition; 39 EXPORT_SYMBOL_GPL(hv_root_partition); 40 41 struct ms_hyperv_info ms_hyperv; 42 EXPORT_SYMBOL_GPL(ms_hyperv); 43 44 #if IS_ENABLED(CONFIG_HYPERV) 45 static void (*vmbus_handler)(void); 46 static void (*hv_stimer0_handler)(void); 47 static void (*hv_kexec_handler)(void); 48 static void (*hv_crash_handler)(struct pt_regs *regs); 49 50 DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_callback) 51 { 52 struct pt_regs *old_regs = set_irq_regs(regs); 53 54 inc_irq_stat(irq_hv_callback_count); 55 if (vmbus_handler) 56 vmbus_handler(); 57 58 if (ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED) 59 ack_APIC_irq(); 60 61 set_irq_regs(old_regs); 62 } 63 64 void hv_setup_vmbus_handler(void (*handler)(void)) 65 { 66 vmbus_handler = handler; 67 } 68 EXPORT_SYMBOL_GPL(hv_setup_vmbus_handler); 69 70 void hv_remove_vmbus_handler(void) 71 { 72 /* We have no way to deallocate the interrupt gate */ 73 vmbus_handler = NULL; 74 } 75 EXPORT_SYMBOL_GPL(hv_remove_vmbus_handler); 76 77 /* 78 * Routines to do per-architecture handling of stimer0 79 * interrupts when in Direct Mode 80 */ 81 DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_stimer0) 82 { 83 struct pt_regs *old_regs = set_irq_regs(regs); 84 85 inc_irq_stat(hyperv_stimer0_count); 86 if (hv_stimer0_handler) 87 hv_stimer0_handler(); 88 add_interrupt_randomness(HYPERV_STIMER0_VECTOR, 0); 89 ack_APIC_irq(); 90 91 set_irq_regs(old_regs); 92 } 93 94 /* For x86/x64, override weak placeholders in hyperv_timer.c */ 95 void hv_setup_stimer0_handler(void (*handler)(void)) 96 { 97 hv_stimer0_handler = handler; 98 } 99 100 void hv_remove_stimer0_handler(void) 101 { 102 /* We have no way to deallocate the interrupt gate */ 103 hv_stimer0_handler = NULL; 104 } 105 106 void hv_setup_kexec_handler(void (*handler)(void)) 107 { 108 hv_kexec_handler = handler; 109 } 110 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler); 111 112 void hv_remove_kexec_handler(void) 113 { 114 hv_kexec_handler = NULL; 115 } 116 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler); 117 118 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs)) 119 { 120 hv_crash_handler = handler; 121 } 122 EXPORT_SYMBOL_GPL(hv_setup_crash_handler); 123 124 void hv_remove_crash_handler(void) 125 { 126 hv_crash_handler = NULL; 127 } 128 EXPORT_SYMBOL_GPL(hv_remove_crash_handler); 129 130 #ifdef CONFIG_KEXEC_CORE 131 static void hv_machine_shutdown(void) 132 { 133 if (kexec_in_progress && hv_kexec_handler) 134 hv_kexec_handler(); 135 136 /* 137 * Call hv_cpu_die() on all the CPUs, otherwise later the hypervisor 138 * corrupts the old VP Assist Pages and can crash the kexec kernel. 139 */ 140 if (kexec_in_progress && hyperv_init_cpuhp > 0) 141 cpuhp_remove_state(hyperv_init_cpuhp); 142 143 /* The function calls stop_other_cpus(). */ 144 native_machine_shutdown(); 145 146 /* Disable the hypercall page when there is only 1 active CPU. */ 147 if (kexec_in_progress) 148 hyperv_cleanup(); 149 } 150 151 static void hv_machine_crash_shutdown(struct pt_regs *regs) 152 { 153 if (hv_crash_handler) 154 hv_crash_handler(regs); 155 156 /* The function calls crash_smp_send_stop(). */ 157 native_machine_crash_shutdown(regs); 158 159 /* Disable the hypercall page when there is only 1 active CPU. */ 160 hyperv_cleanup(); 161 } 162 #endif /* CONFIG_KEXEC_CORE */ 163 #endif /* CONFIG_HYPERV */ 164 165 static uint32_t __init ms_hyperv_platform(void) 166 { 167 u32 eax; 168 u32 hyp_signature[3]; 169 170 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) 171 return 0; 172 173 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS, 174 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]); 175 176 if (eax >= HYPERV_CPUID_MIN && 177 eax <= HYPERV_CPUID_MAX && 178 !memcmp("Microsoft Hv", hyp_signature, 12)) 179 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS; 180 181 return 0; 182 } 183 184 static unsigned char hv_get_nmi_reason(void) 185 { 186 return 0; 187 } 188 189 #ifdef CONFIG_X86_LOCAL_APIC 190 /* 191 * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes 192 * it difficult to process CHANNELMSG_UNLOAD in case of crash. Handle 193 * unknown NMI on the first CPU which gets it. 194 */ 195 static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs) 196 { 197 static atomic_t nmi_cpu = ATOMIC_INIT(-1); 198 199 if (!unknown_nmi_panic) 200 return NMI_DONE; 201 202 if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1) 203 return NMI_HANDLED; 204 205 return NMI_DONE; 206 } 207 #endif 208 209 static unsigned long hv_get_tsc_khz(void) 210 { 211 unsigned long freq; 212 213 rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq); 214 215 return freq / 1000; 216 } 217 218 #if defined(CONFIG_SMP) && IS_ENABLED(CONFIG_HYPERV) 219 static void __init hv_smp_prepare_boot_cpu(void) 220 { 221 native_smp_prepare_boot_cpu(); 222 #if defined(CONFIG_X86_64) && defined(CONFIG_PARAVIRT_SPINLOCKS) 223 hv_init_spinlocks(); 224 #endif 225 } 226 227 static void __init hv_smp_prepare_cpus(unsigned int max_cpus) 228 { 229 #ifdef CONFIG_X86_64 230 int i; 231 int ret; 232 #endif 233 234 native_smp_prepare_cpus(max_cpus); 235 236 #ifdef CONFIG_X86_64 237 for_each_present_cpu(i) { 238 if (i == 0) 239 continue; 240 ret = hv_call_add_logical_proc(numa_cpu_node(i), i, cpu_physical_id(i)); 241 BUG_ON(ret); 242 } 243 244 for_each_present_cpu(i) { 245 if (i == 0) 246 continue; 247 ret = hv_call_create_vp(numa_cpu_node(i), hv_current_partition_id, i, i); 248 BUG_ON(ret); 249 } 250 #endif 251 } 252 #endif 253 254 static void __init ms_hyperv_init_platform(void) 255 { 256 int hv_max_functions_eax; 257 int hv_host_info_eax; 258 int hv_host_info_ebx; 259 int hv_host_info_ecx; 260 int hv_host_info_edx; 261 262 #ifdef CONFIG_PARAVIRT 263 pv_info.name = "Hyper-V"; 264 #endif 265 266 /* 267 * Extract the features and hints 268 */ 269 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES); 270 ms_hyperv.priv_high = cpuid_ebx(HYPERV_CPUID_FEATURES); 271 ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES); 272 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO); 273 274 hv_max_functions_eax = cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS); 275 276 pr_info("Hyper-V: privilege flags low 0x%x, high 0x%x, hints 0x%x, misc 0x%x\n", 277 ms_hyperv.features, ms_hyperv.priv_high, ms_hyperv.hints, 278 ms_hyperv.misc_features); 279 280 ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS); 281 ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS); 282 283 pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n", 284 ms_hyperv.max_vp_index, ms_hyperv.max_lp_index); 285 286 /* 287 * Check CPU management privilege. 288 * 289 * To mirror what Windows does we should extract CPU management 290 * features and use the ReservedIdentityBit to detect if Linux is the 291 * root partition. But that requires negotiating CPU management 292 * interface (a process to be finalized). 293 * 294 * For now, use the privilege flag as the indicator for running as 295 * root. 296 */ 297 if (cpuid_ebx(HYPERV_CPUID_FEATURES) & HV_CPU_MANAGEMENT) { 298 hv_root_partition = true; 299 pr_info("Hyper-V: running as root partition\n"); 300 } 301 302 /* 303 * Extract host information. 304 */ 305 if (hv_max_functions_eax >= HYPERV_CPUID_VERSION) { 306 hv_host_info_eax = cpuid_eax(HYPERV_CPUID_VERSION); 307 hv_host_info_ebx = cpuid_ebx(HYPERV_CPUID_VERSION); 308 hv_host_info_ecx = cpuid_ecx(HYPERV_CPUID_VERSION); 309 hv_host_info_edx = cpuid_edx(HYPERV_CPUID_VERSION); 310 311 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n", 312 hv_host_info_eax, hv_host_info_ebx >> 16, 313 hv_host_info_ebx & 0xFFFF, hv_host_info_ecx, 314 hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF); 315 } 316 317 if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS && 318 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { 319 x86_platform.calibrate_tsc = hv_get_tsc_khz; 320 x86_platform.calibrate_cpu = hv_get_tsc_khz; 321 } 322 323 if (ms_hyperv.priv_high & HV_ISOLATION) { 324 ms_hyperv.isolation_config_a = cpuid_eax(HYPERV_CPUID_ISOLATION_CONFIG); 325 ms_hyperv.isolation_config_b = cpuid_ebx(HYPERV_CPUID_ISOLATION_CONFIG); 326 327 pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B 0x%x\n", 328 ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b); 329 } 330 331 if (hv_max_functions_eax >= HYPERV_CPUID_NESTED_FEATURES) { 332 ms_hyperv.nested_features = 333 cpuid_eax(HYPERV_CPUID_NESTED_FEATURES); 334 pr_info("Hyper-V: Nested features: 0x%x\n", 335 ms_hyperv.nested_features); 336 } 337 338 /* 339 * Hyper-V expects to get crash register data or kmsg when 340 * crash enlightment is available and system crashes. Set 341 * crash_kexec_post_notifiers to be true to make sure that 342 * calling crash enlightment interface before running kdump 343 * kernel. 344 */ 345 if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) 346 crash_kexec_post_notifiers = true; 347 348 #ifdef CONFIG_X86_LOCAL_APIC 349 if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS && 350 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { 351 /* 352 * Get the APIC frequency. 353 */ 354 u64 hv_lapic_frequency; 355 356 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency); 357 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ); 358 lapic_timer_period = hv_lapic_frequency; 359 pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n", 360 lapic_timer_period); 361 } 362 363 register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST, 364 "hv_nmi_unknown"); 365 #endif 366 367 #ifdef CONFIG_X86_IO_APIC 368 no_timer_check = 1; 369 #endif 370 371 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE) 372 machine_ops.shutdown = hv_machine_shutdown; 373 machine_ops.crash_shutdown = hv_machine_crash_shutdown; 374 #endif 375 if (ms_hyperv.features & HV_ACCESS_TSC_INVARIANT) { 376 wrmsrl(HV_X64_MSR_TSC_INVARIANT_CONTROL, 0x1); 377 setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE); 378 } else { 379 mark_tsc_unstable("running on Hyper-V"); 380 } 381 382 /* 383 * Generation 2 instances don't support reading the NMI status from 384 * 0x61 port. 385 */ 386 if (efi_enabled(EFI_BOOT)) 387 x86_platform.get_nmi_reason = hv_get_nmi_reason; 388 389 /* 390 * Hyper-V VMs have a PIT emulation quirk such that zeroing the 391 * counter register during PIT shutdown restarts the PIT. So it 392 * continues to interrupt @18.2 HZ. Setting i8253_clear_counter 393 * to false tells pit_shutdown() not to zero the counter so that 394 * the PIT really is shutdown. Generation 2 VMs don't have a PIT, 395 * and setting this value has no effect. 396 */ 397 i8253_clear_counter_on_shutdown = false; 398 399 #if IS_ENABLED(CONFIG_HYPERV) 400 /* 401 * Setup the hook to get control post apic initialization. 402 */ 403 x86_platform.apic_post_init = hyperv_init; 404 hyperv_setup_mmu_ops(); 405 /* Setup the IDT for hypervisor callback */ 406 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_hyperv_callback); 407 408 /* Setup the IDT for reenlightenment notifications */ 409 if (ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT) { 410 alloc_intr_gate(HYPERV_REENLIGHTENMENT_VECTOR, 411 asm_sysvec_hyperv_reenlightenment); 412 } 413 414 /* Setup the IDT for stimer0 */ 415 if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE) { 416 alloc_intr_gate(HYPERV_STIMER0_VECTOR, 417 asm_sysvec_hyperv_stimer0); 418 } 419 420 # ifdef CONFIG_SMP 421 smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu; 422 if (hv_root_partition) 423 smp_ops.smp_prepare_cpus = hv_smp_prepare_cpus; 424 # endif 425 426 /* 427 * Hyper-V doesn't provide irq remapping for IO-APIC. To enable x2apic, 428 * set x2apic destination mode to physical mode when x2apic is available 429 * and Hyper-V IOMMU driver makes sure cpus assigned with IO-APIC irqs 430 * have 8-bit APIC id. 431 */ 432 # ifdef CONFIG_X86_X2APIC 433 if (x2apic_supported()) 434 x2apic_phys = 1; 435 # endif 436 437 /* Register Hyper-V specific clocksource */ 438 hv_init_clocksource(); 439 #endif 440 } 441 442 static bool __init ms_hyperv_x2apic_available(void) 443 { 444 return x2apic_supported(); 445 } 446 447 /* 448 * If ms_hyperv_msi_ext_dest_id() returns true, hyperv_prepare_irq_remapping() 449 * returns -ENODEV and the Hyper-V IOMMU driver is not used; instead, the 450 * generic support of the 15-bit APIC ID is used: see __irq_msi_compose_msg(). 451 * 452 * Note: for a VM on Hyper-V, the I/O-APIC is the only device which 453 * (logically) generates MSIs directly to the system APIC irq domain. 454 * There is no HPET, and PCI MSI/MSI-X interrupts are remapped by the 455 * pci-hyperv host bridge. 456 */ 457 static bool __init ms_hyperv_msi_ext_dest_id(void) 458 { 459 u32 eax; 460 461 eax = cpuid_eax(HYPERV_CPUID_VIRT_STACK_INTERFACE); 462 if (eax != HYPERV_VS_INTERFACE_EAX_SIGNATURE) 463 return false; 464 465 eax = cpuid_eax(HYPERV_CPUID_VIRT_STACK_PROPERTIES); 466 return eax & HYPERV_VS_PROPERTIES_EAX_EXTENDED_IOAPIC_RTE; 467 } 468 469 const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = { 470 .name = "Microsoft Hyper-V", 471 .detect = ms_hyperv_platform, 472 .type = X86_HYPER_MS_HYPERV, 473 .init.x2apic_available = ms_hyperv_x2apic_available, 474 .init.msi_ext_dest_id = ms_hyperv_msi_ext_dest_id, 475 .init.init_platform = ms_hyperv_init_platform, 476 }; 477