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 <[email protected]>
   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 };