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(); 138 139 /* 140 * Call hv_cpu_die() on all the CPUs, otherwise later the hypervisor 141 * corrupts the old VP Assist Pages and can crash the kexec kernel. 142 */ 143 if (kexec_in_progress && hyperv_init_cpuhp > 0) 144 cpuhp_remove_state(hyperv_init_cpuhp); 145 146 /* The function calls stop_other_cpus(). */ 147 native_machine_shutdown(); 148 149 /* Disable the hypercall page when there is only 1 active CPU. */ 150 if (kexec_in_progress) 151 hyperv_cleanup(); 152 } 153 154 static void hv_machine_crash_shutdown(struct pt_regs *regs) 155 { 156 if (hv_crash_handler) 157 hv_crash_handler(regs); 158 159 /* The function calls crash_smp_send_stop(). */ 160 native_machine_crash_shutdown(regs); 161 162 /* Disable the hypercall page when there is only 1 active CPU. */ 163 hyperv_cleanup(); 164 } 165 #endif /* CONFIG_KEXEC_CORE */ 166 #endif /* CONFIG_HYPERV */ 167 168 static uint32_t __init ms_hyperv_platform(void) 169 { 170 u32 eax; 171 u32 hyp_signature[3]; 172 173 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) 174 return 0; 175 176 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS, 177 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]); 178 179 if (eax >= HYPERV_CPUID_MIN && 180 eax <= HYPERV_CPUID_MAX && 181 !memcmp("Microsoft Hv", hyp_signature, 12)) 182 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS; 183 184 return 0; 185 } 186 187 static unsigned char hv_get_nmi_reason(void) 188 { 189 return 0; 190 } 191 192 #ifdef CONFIG_X86_LOCAL_APIC 193 /* 194 * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes 195 * it dificult to process CHANNELMSG_UNLOAD in case of crash. Handle 196 * unknown NMI on the first CPU which gets it. 197 */ 198 static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs) 199 { 200 static atomic_t nmi_cpu = ATOMIC_INIT(-1); 201 202 if (!unknown_nmi_panic) 203 return NMI_DONE; 204 205 if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1) 206 return NMI_HANDLED; 207 208 return NMI_DONE; 209 } 210 #endif 211 212 static unsigned long hv_get_tsc_khz(void) 213 { 214 unsigned long freq; 215 216 rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq); 217 218 return freq / 1000; 219 } 220 221 #if defined(CONFIG_SMP) && IS_ENABLED(CONFIG_HYPERV) 222 static void __init hv_smp_prepare_boot_cpu(void) 223 { 224 native_smp_prepare_boot_cpu(); 225 #if defined(CONFIG_X86_64) && defined(CONFIG_PARAVIRT_SPINLOCKS) 226 hv_init_spinlocks(); 227 #endif 228 } 229 #endif 230 231 static void __init ms_hyperv_init_platform(void) 232 { 233 int hv_host_info_eax; 234 int hv_host_info_ebx; 235 int hv_host_info_ecx; 236 int hv_host_info_edx; 237 238 #ifdef CONFIG_PARAVIRT 239 pv_info.name = "Hyper-V"; 240 #endif 241 242 /* 243 * Extract the features and hints 244 */ 245 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES); 246 ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES); 247 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO); 248 249 pr_info("Hyper-V: features 0x%x, hints 0x%x, misc 0x%x\n", 250 ms_hyperv.features, ms_hyperv.hints, ms_hyperv.misc_features); 251 252 ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS); 253 ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS); 254 255 pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n", 256 ms_hyperv.max_vp_index, ms_hyperv.max_lp_index); 257 258 /* 259 * Extract host information. 260 */ 261 if (cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS) >= 262 HYPERV_CPUID_VERSION) { 263 hv_host_info_eax = cpuid_eax(HYPERV_CPUID_VERSION); 264 hv_host_info_ebx = cpuid_ebx(HYPERV_CPUID_VERSION); 265 hv_host_info_ecx = cpuid_ecx(HYPERV_CPUID_VERSION); 266 hv_host_info_edx = cpuid_edx(HYPERV_CPUID_VERSION); 267 268 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n", 269 hv_host_info_eax, hv_host_info_ebx >> 16, 270 hv_host_info_ebx & 0xFFFF, hv_host_info_ecx, 271 hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF); 272 } 273 274 if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS && 275 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { 276 x86_platform.calibrate_tsc = hv_get_tsc_khz; 277 x86_platform.calibrate_cpu = hv_get_tsc_khz; 278 } 279 280 if (ms_hyperv.hints & HV_X64_ENLIGHTENED_VMCS_RECOMMENDED) { 281 ms_hyperv.nested_features = 282 cpuid_eax(HYPERV_CPUID_NESTED_FEATURES); 283 } 284 285 /* 286 * Hyper-V expects to get crash register data or kmsg when 287 * crash enlightment is available and system crashes. Set 288 * crash_kexec_post_notifiers to be true to make sure that 289 * calling crash enlightment interface before running kdump 290 * kernel. 291 */ 292 if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE) 293 crash_kexec_post_notifiers = true; 294 295 #ifdef CONFIG_X86_LOCAL_APIC 296 if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS && 297 ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) { 298 /* 299 * Get the APIC frequency. 300 */ 301 u64 hv_lapic_frequency; 302 303 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency); 304 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ); 305 lapic_timer_period = hv_lapic_frequency; 306 pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n", 307 lapic_timer_period); 308 } 309 310 register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST, 311 "hv_nmi_unknown"); 312 #endif 313 314 #ifdef CONFIG_X86_IO_APIC 315 no_timer_check = 1; 316 #endif 317 318 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE) 319 machine_ops.shutdown = hv_machine_shutdown; 320 machine_ops.crash_shutdown = hv_machine_crash_shutdown; 321 #endif 322 if (ms_hyperv.features & HV_ACCESS_TSC_INVARIANT) { 323 wrmsrl(HV_X64_MSR_TSC_INVARIANT_CONTROL, 0x1); 324 setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE); 325 } else { 326 mark_tsc_unstable("running on Hyper-V"); 327 } 328 329 /* 330 * Generation 2 instances don't support reading the NMI status from 331 * 0x61 port. 332 */ 333 if (efi_enabled(EFI_BOOT)) 334 x86_platform.get_nmi_reason = hv_get_nmi_reason; 335 336 /* 337 * Hyper-V VMs have a PIT emulation quirk such that zeroing the 338 * counter register during PIT shutdown restarts the PIT. So it 339 * continues to interrupt @18.2 HZ. Setting i8253_clear_counter 340 * to false tells pit_shutdown() not to zero the counter so that 341 * the PIT really is shutdown. Generation 2 VMs don't have a PIT, 342 * and setting this value has no effect. 343 */ 344 i8253_clear_counter_on_shutdown = false; 345 346 #if IS_ENABLED(CONFIG_HYPERV) 347 /* 348 * Setup the hook to get control post apic initialization. 349 */ 350 x86_platform.apic_post_init = hyperv_init; 351 hyperv_setup_mmu_ops(); 352 /* Setup the IDT for hypervisor callback */ 353 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_hyperv_callback); 354 355 /* Setup the IDT for reenlightenment notifications */ 356 if (ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT) { 357 alloc_intr_gate(HYPERV_REENLIGHTENMENT_VECTOR, 358 asm_sysvec_hyperv_reenlightenment); 359 } 360 361 /* Setup the IDT for stimer0 */ 362 if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE) { 363 alloc_intr_gate(HYPERV_STIMER0_VECTOR, 364 asm_sysvec_hyperv_stimer0); 365 } 366 367 # ifdef CONFIG_SMP 368 smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu; 369 # endif 370 371 /* 372 * Hyper-V doesn't provide irq remapping for IO-APIC. To enable x2apic, 373 * set x2apic destination mode to physcial mode when x2apic is available 374 * and Hyper-V IOMMU driver makes sure cpus assigned with IO-APIC irqs 375 * have 8-bit APIC id. 376 */ 377 # ifdef CONFIG_X86_X2APIC 378 if (x2apic_supported()) 379 x2apic_phys = 1; 380 # endif 381 382 /* Register Hyper-V specific clocksource */ 383 hv_init_clocksource(); 384 #endif 385 } 386 387 static bool __init ms_hyperv_x2apic_available(void) 388 { 389 return x2apic_supported(); 390 } 391 392 /* 393 * If ms_hyperv_msi_ext_dest_id() returns true, hyperv_prepare_irq_remapping() 394 * returns -ENODEV and the Hyper-V IOMMU driver is not used; instead, the 395 * generic support of the 15-bit APIC ID is used: see __irq_msi_compose_msg(). 396 * 397 * Note: for a VM on Hyper-V, the I/O-APIC is the only device which 398 * (logically) generates MSIs directly to the system APIC irq domain. 399 * There is no HPET, and PCI MSI/MSI-X interrupts are remapped by the 400 * pci-hyperv host bridge. 401 */ 402 static bool __init ms_hyperv_msi_ext_dest_id(void) 403 { 404 u32 eax; 405 406 eax = cpuid_eax(HYPERV_CPUID_VIRT_STACK_INTERFACE); 407 if (eax != HYPERV_VS_INTERFACE_EAX_SIGNATURE) 408 return false; 409 410 eax = cpuid_eax(HYPERV_CPUID_VIRT_STACK_PROPERTIES); 411 return eax & HYPERV_VS_PROPERTIES_EAX_EXTENDED_IOAPIC_RTE; 412 } 413 414 const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = { 415 .name = "Microsoft Hyper-V", 416 .detect = ms_hyperv_platform, 417 .type = X86_HYPER_MS_HYPERV, 418 .init.x2apic_available = ms_hyperv_x2apic_available, 419 .init.msi_ext_dest_id = ms_hyperv_msi_ext_dest_id, 420 .init.init_platform = ms_hyperv_init_platform, 421 }; 422