arch/x86/kernel/cpu/mshyperv.c

   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 #include <asm/numa.h>
  35
  36 /* Is Linux running as the root partition? */
  37 bool hv_root_partition;
  38 EXPORT_SYMBOL_GPL(hv_root_partition);
  39
  40 struct ms_hyperv_info ms_hyperv;
  41 EXPORT_SYMBOL_GPL(ms_hyperv);
  42
  43 #if IS_ENABLED(CONFIG_HYPERV)
  44 static void (*vmbus_handler)(void);
  45 static void (*hv_stimer0_handler)(void);
  46 static void (*hv_kexec_handler)(void);
  47 static void (*hv_crash_handler)(struct pt_regs *regs);
  48
  49 DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_callback)
  50 {
  51         struct pt_regs *old_regs = set_irq_regs(regs);
  52
  53         inc_irq_stat(irq_hv_callback_count);
  54         if (vmbus_handler)
  55                 vmbus_handler();
  56
  57         if (ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED)
  58                 ack_APIC_irq();
  59
  60         set_irq_regs(old_regs);
  61 }
  62
  63 void hv_setup_vmbus_handler(void (*handler)(void))
  64 {
  65         vmbus_handler = handler;
  66 }
  67 EXPORT_SYMBOL_GPL(hv_setup_vmbus_handler);
  68
  69 void hv_remove_vmbus_handler(void)
  70 {
  71         /* We have no way to deallocate the interrupt gate */
  72         vmbus_handler = NULL;
  73 }
  74 EXPORT_SYMBOL_GPL(hv_remove_vmbus_handler);
  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 /* For x86/x64, override weak placeholders in hyperv_timer.c */
  94 void hv_setup_stimer0_handler(void (*handler)(void))
  95 {
  96         hv_stimer0_handler = handler;
  97 }
  98
  99 void hv_remove_stimer0_handler(void)
 100 {
 101         /* We have no way to deallocate the interrupt gate */
 102         hv_stimer0_handler = NULL;
 103 }
 104
 105 void hv_setup_kexec_handler(void (*handler)(void))
 106 {
 107         hv_kexec_handler = handler;
 108 }
 109 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler);
 110
 111 void hv_remove_kexec_handler(void)
 112 {
 113         hv_kexec_handler = NULL;
 114 }
 115 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler);
 116
 117 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs))
 118 {
 119         hv_crash_handler = handler;
 120 }
 121 EXPORT_SYMBOL_GPL(hv_setup_crash_handler);
 122
 123 void hv_remove_crash_handler(void)
 124 {
 125         hv_crash_handler = NULL;
 126 }
 127 EXPORT_SYMBOL_GPL(hv_remove_crash_handler);
 128
 129 #ifdef CONFIG_KEXEC_CORE
 130 static void hv_machine_shutdown(void)
 131 {
 132         if (kexec_in_progress && hv_kexec_handler)
 133                 hv_kexec_handler();
 134
 135         /*
 136          * Call hv_cpu_die() on all the CPUs, otherwise later the hypervisor
 137          * corrupts the old VP Assist Pages and can crash the kexec kernel.
 138          */
 139         if (kexec_in_progress && hyperv_init_cpuhp > 0)
 140                 cpuhp_remove_state(hyperv_init_cpuhp);
 141
 142         /* The function calls stop_other_cpus(). */
 143         native_machine_shutdown();
 144
 145         /* Disable the hypercall page when there is only 1 active CPU. */
 146         if (kexec_in_progress)
 147                 hyperv_cleanup();
 148 }
 149
 150 static void hv_machine_crash_shutdown(struct pt_regs *regs)
 151 {
 152         if (hv_crash_handler)
 153                 hv_crash_handler(regs);
 154
 155         /* The function calls crash_smp_send_stop(). */
 156         native_machine_crash_shutdown(regs);
 157
 158         /* Disable the hypercall page when there is only 1 active CPU. */
 159         hyperv_cleanup();
 160 }
 161 #endif /* CONFIG_KEXEC_CORE */
 162 #endif /* CONFIG_HYPERV */
 163
 164 static uint32_t  __init ms_hyperv_platform(void)
 165 {
 166         u32 eax;
 167         u32 hyp_signature[3];
 168
 169         if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
 170                 return 0;
 171
 172         cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
 173               &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
 174
 175         if (eax >= HYPERV_CPUID_MIN &&
 176             eax <= HYPERV_CPUID_MAX &&
 177             !memcmp("Microsoft Hv", hyp_signature, 12))
 178                 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS;
 179
 180         return 0;
 181 }
 182
 183 static unsigned char hv_get_nmi_reason(void)
 184 {
 185         return 0;
 186 }
 187
 188 #ifdef CONFIG_X86_LOCAL_APIC
 189 /*
 190  * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes
 191  * it difficult to process CHANNELMSG_UNLOAD in case of crash. Handle
 192  * unknown NMI on the first CPU which gets it.
 193  */
 194 static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs)
 195 {
 196         static atomic_t nmi_cpu = ATOMIC_INIT(-1);
 197
 198         if (!unknown_nmi_panic)
 199                 return NMI_DONE;
 200
 201         if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1)
 202                 return NMI_HANDLED;
 203
 204         return NMI_DONE;
 205 }
 206 #endif
 207
 208 static unsigned long hv_get_tsc_khz(void)
 209 {
 210         unsigned long freq;
 211
 212         rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
 213
 214         return freq / 1000;
 215 }
 216
 217 #if defined(CONFIG_SMP) && IS_ENABLED(CONFIG_HYPERV)
 218 static void __init hv_smp_prepare_boot_cpu(void)
 219 {
 220         native_smp_prepare_boot_cpu();
 221 #if defined(CONFIG_X86_64) && defined(CONFIG_PARAVIRT_SPINLOCKS)
 222         hv_init_spinlocks();
 223 #endif
 224 }
 225
 226 static void __init hv_smp_prepare_cpus(unsigned int max_cpus)
 227 {
 228 #ifdef CONFIG_X86_64
 229         int i;
 230         int ret;
 231 #endif
 232
 233         native_smp_prepare_cpus(max_cpus);
 234
 235 #ifdef CONFIG_X86_64
 236         for_each_present_cpu(i) {
 237                 if (i == 0)
 238                         continue;
 239                 ret = hv_call_add_logical_proc(numa_cpu_node(i), i, cpu_physical_id(i));
 240                 BUG_ON(ret);
 241         }
 242
 243         for_each_present_cpu(i) {
 244                 if (i == 0)
 245                         continue;
 246                 ret = hv_call_create_vp(numa_cpu_node(i), hv_current_partition_id, i, i);
 247                 BUG_ON(ret);
 248         }
 249 #endif
 250 }
 251 #endif
 252
 253 static void __init ms_hyperv_init_platform(void)
 254 {
 255         int hv_host_info_eax;
 256         int hv_host_info_ebx;
 257         int hv_host_info_ecx;
 258         int hv_host_info_edx;
 259
 260 #ifdef CONFIG_PARAVIRT
 261         pv_info.name = "Hyper-V";
 262 #endif
 263
 264         /*
 265          * Extract the features and hints
 266          */
 267         ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
 268         ms_hyperv.priv_high = cpuid_ebx(HYPERV_CPUID_FEATURES);
 269         ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
 270         ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
 271
 272         pr_info("Hyper-V: privilege flags low 0x%x, high 0x%x, hints 0x%x, misc 0x%x\n",
 273                 ms_hyperv.features, ms_hyperv.priv_high, ms_hyperv.hints,
 274                 ms_hyperv.misc_features);
 275
 276         ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS);
 277         ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS);
 278
 279         pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n",
 280                  ms_hyperv.max_vp_index, ms_hyperv.max_lp_index);
 281
 282         /*
 283          * Check CPU management privilege.
 284          *
 285          * To mirror what Windows does we should extract CPU management
 286          * features and use the ReservedIdentityBit to detect if Linux is the
 287          * root partition. But that requires negotiating CPU management
 288          * interface (a process to be finalized).
 289          *
 290          * For now, use the privilege flag as the indicator for running as
 291          * root.
 292          */
 293         if (cpuid_ebx(HYPERV_CPUID_FEATURES) & HV_CPU_MANAGEMENT) {
 294                 hv_root_partition = true;
 295                 pr_info("Hyper-V: running as root partition\n");
 296         }
 297
 298         /*
 299          * Extract host information.
 300          */
 301         if (cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS) >=
 302             HYPERV_CPUID_VERSION) {
 303                 hv_host_info_eax = cpuid_eax(HYPERV_CPUID_VERSION);
 304                 hv_host_info_ebx = cpuid_ebx(HYPERV_CPUID_VERSION);
 305                 hv_host_info_ecx = cpuid_ecx(HYPERV_CPUID_VERSION);
 306                 hv_host_info_edx = cpuid_edx(HYPERV_CPUID_VERSION);
 307
 308                 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n",
 309                         hv_host_info_eax, hv_host_info_ebx >> 16,
 310                         hv_host_info_ebx & 0xFFFF, hv_host_info_ecx,
 311                         hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF);
 312         }
 313
 314         if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
 315             ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
 316                 x86_platform.calibrate_tsc = hv_get_tsc_khz;
 317                 x86_platform.calibrate_cpu = hv_get_tsc_khz;
 318         }
 319
 320         if (ms_hyperv.priv_high & HV_ISOLATION) {
 321                 ms_hyperv.isolation_config_a = cpuid_eax(HYPERV_CPUID_ISOLATION_CONFIG);
 322                 ms_hyperv.isolation_config_b = cpuid_ebx(HYPERV_CPUID_ISOLATION_CONFIG);
 323
 324                 pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B 0x%x\n",
 325                         ms_hyperv.isolation_config_a, ms_hyperv.isolation_config_b);
 326         }
 327
 328         if (ms_hyperv.hints & HV_X64_ENLIGHTENED_VMCS_RECOMMENDED) {
 329                 ms_hyperv.nested_features =
 330                         cpuid_eax(HYPERV_CPUID_NESTED_FEATURES);
 331         }
 332
 333         /*
 334          * Hyper-V expects to get crash register data or kmsg when
 335          * crash enlightment is available and system crashes. Set
 336          * crash_kexec_post_notifiers to be true to make sure that
 337          * calling crash enlightment interface before running kdump
 338          * kernel.
 339          */
 340         if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE)
 341                 crash_kexec_post_notifiers = true;
 342
 343 #ifdef CONFIG_X86_LOCAL_APIC
 344         if (ms_hyperv.features & HV_ACCESS_FREQUENCY_MSRS &&
 345             ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
 346                 /*
 347                  * Get the APIC frequency.
 348                  */
 349                 u64     hv_lapic_frequency;
 350
 351                 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency);
 352                 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ);
 353                 lapic_timer_period = hv_lapic_frequency;
 354                 pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n",
 355                         lapic_timer_period);
 356         }
 357
 358         register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST,
 359                              "hv_nmi_unknown");
 360 #endif
 361
 362 #ifdef CONFIG_X86_IO_APIC
 363         no_timer_check = 1;
 364 #endif
 365
 366 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE)
 367         machine_ops.shutdown = hv_machine_shutdown;
 368         machine_ops.crash_shutdown = hv_machine_crash_shutdown;
 369 #endif
 370         if (ms_hyperv.features & HV_ACCESS_TSC_INVARIANT) {
 371                 wrmsrl(HV_X64_MSR_TSC_INVARIANT_CONTROL, 0x1);
 372                 setup_force_cpu_cap(X86_FEATURE_TSC_RELIABLE);
 373         } else {
 374                 mark_tsc_unstable("running on Hyper-V");
 375         }
 376
 377         /*
 378          * Generation 2 instances don't support reading the NMI status from
 379          * 0x61 port.
 380          */
 381         if (efi_enabled(EFI_BOOT))
 382                 x86_platform.get_nmi_reason = hv_get_nmi_reason;
 383
 384         /*
 385          * Hyper-V VMs have a PIT emulation quirk such that zeroing the
 386          * counter register during PIT shutdown restarts the PIT. So it
 387          * continues to interrupt @18.2 HZ. Setting i8253_clear_counter
 388          * to false tells pit_shutdown() not to zero the counter so that
 389          * the PIT really is shutdown. Generation 2 VMs don't have a PIT,
 390          * and setting this value has no effect.
 391          */
 392         i8253_clear_counter_on_shutdown = false;
 393
 394 #if IS_ENABLED(CONFIG_HYPERV)
 395         /*
 396          * Setup the hook to get control post apic initialization.
 397          */
 398         x86_platform.apic_post_init = hyperv_init;
 399         hyperv_setup_mmu_ops();
 400         /* Setup the IDT for hypervisor callback */
 401         alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, asm_sysvec_hyperv_callback);
 402
 403         /* Setup the IDT for reenlightenment notifications */
 404         if (ms_hyperv.features & HV_ACCESS_REENLIGHTENMENT) {
 405                 alloc_intr_gate(HYPERV_REENLIGHTENMENT_VECTOR,
 406                                 asm_sysvec_hyperv_reenlightenment);
 407         }
 408
 409         /* Setup the IDT for stimer0 */
 410         if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE) {
 411                 alloc_intr_gate(HYPERV_STIMER0_VECTOR,
 412                                 asm_sysvec_hyperv_stimer0);
 413         }
 414
 415 # ifdef CONFIG_SMP
 416         smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu;
 417         if (hv_root_partition)
 418                 smp_ops.smp_prepare_cpus = hv_smp_prepare_cpus;
 419 # endif
 420
 421         /*
 422          * Hyper-V doesn't provide irq remapping for IO-APIC. To enable x2apic,
 423          * set x2apic destination mode to physical mode when x2apic is available
 424          * and Hyper-V IOMMU driver makes sure cpus assigned with IO-APIC irqs
 425          * have 8-bit APIC id.
 426          */
 427 # ifdef CONFIG_X86_X2APIC
 428         if (x2apic_supported())
 429                 x2apic_phys = 1;
 430 # endif
 431
 432         /* Register Hyper-V specific clocksource */
 433         hv_init_clocksource();
 434 #endif
 435 }
 436
 437 static bool __init ms_hyperv_x2apic_available(void)
 438 {
 439         return x2apic_supported();
 440 }
 441
 442 /*
 443  * If ms_hyperv_msi_ext_dest_id() returns true, hyperv_prepare_irq_remapping()
 444  * returns -ENODEV and the Hyper-V IOMMU driver is not used; instead, the
 445  * generic support of the 15-bit APIC ID is used: see __irq_msi_compose_msg().
 446  *
 447  * Note: for a VM on Hyper-V, the I/O-APIC is the only device which
 448  * (logically) generates MSIs directly to the system APIC irq domain.
 449  * There is no HPET, and PCI MSI/MSI-X interrupts are remapped by the
 450  * pci-hyperv host bridge.
 451  */
 452 static bool __init ms_hyperv_msi_ext_dest_id(void)
 453 {
 454         u32 eax;
 455
 456         eax = cpuid_eax(HYPERV_CPUID_VIRT_STACK_INTERFACE);
 457         if (eax != HYPERV_VS_INTERFACE_EAX_SIGNATURE)
 458                 return false;
 459
 460         eax = cpuid_eax(HYPERV_CPUID_VIRT_STACK_PROPERTIES);
 461         return eax & HYPERV_VS_PROPERTIES_EAX_EXTENDED_IOAPIC_RTE;
 462 }
 463
 464 const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
 465         .name                   = "Microsoft Hyper-V",
 466         .detect                 = ms_hyperv_platform,
 467         .type                   = X86_HYPER_MS_HYPERV,
 468         .init.x2apic_available  = ms_hyperv_x2apic_available,
 469         .init.msi_ext_dest_id   = ms_hyperv_msi_ext_dest_id,
 470         .init.init_platform     = ms_hyperv_init_platform,
 471 };