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
  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 };