arch/x86/kernel/cpu/mshyperv.c

   1 /*
   2  * HyperV  Detection code.
   3  *
   4  * Copyright (C) 2010, Novell, Inc.
   5  * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; version 2 of the License.
  10  *
  11  */
  12
  13 #include <linux/types.h>
  14 #include <linux/time.h>
  15 #include <linux/clocksource.h>
  16 #include <linux/init.h>
  17 #include <linux/export.h>
  18 #include <linux/hardirq.h>
  19 #include <linux/efi.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/irq.h>
  22 #include <linux/kexec.h>
  23 #include <linux/i8253.h>
  24 #include <asm/processor.h>
  25 #include <asm/hypervisor.h>
  26 #include <asm/hyperv-tlfs.h>
  27 #include <asm/mshyperv.h>
  28 #include <asm/desc.h>
  29 #include <asm/irq_regs.h>
  30 #include <asm/i8259.h>
  31 #include <asm/apic.h>
  32 #include <asm/timer.h>
  33 #include <asm/reboot.h>
  34 #include <asm/nmi.h>
  35
  36 struct ms_hyperv_info ms_hyperv;
  37 EXPORT_SYMBOL_GPL(ms_hyperv);
  38
  39 #if IS_ENABLED(CONFIG_HYPERV)
  40 static void (*vmbus_handler)(void);
  41 static void (*hv_stimer0_handler)(void);
  42 static void (*hv_kexec_handler)(void);
  43 static void (*hv_crash_handler)(struct pt_regs *regs);
  44
  45 __visible void __irq_entry hyperv_vector_handler(struct pt_regs *regs)
  46 {
  47         struct pt_regs *old_regs = set_irq_regs(regs);
  48
  49         entering_irq();
  50         inc_irq_stat(irq_hv_callback_count);
  51         if (vmbus_handler)
  52                 vmbus_handler();
  53
  54         if (ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED)
  55                 ack_APIC_irq();
  56
  57         exiting_irq();
  58         set_irq_regs(old_regs);
  59 }
  60
  61 void hv_setup_vmbus_irq(void (*handler)(void))
  62 {
  63         vmbus_handler = handler;
  64 }
  65
  66 void hv_remove_vmbus_irq(void)
  67 {
  68         /* We have no way to deallocate the interrupt gate */
  69         vmbus_handler = NULL;
  70 }
  71 EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq);
  72 EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq);
  73
  74 /*
  75  * Routines to do per-architecture handling of stimer0
  76  * interrupts when in Direct Mode
  77  */
  78
  79 __visible void __irq_entry hv_stimer0_vector_handler(struct pt_regs *regs)
  80 {
  81         struct pt_regs *old_regs = set_irq_regs(regs);
  82
  83         entering_irq();
  84         inc_irq_stat(hyperv_stimer0_count);
  85         if (hv_stimer0_handler)
  86                 hv_stimer0_handler();
  87         ack_APIC_irq();
  88
  89         exiting_irq();
  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 = 0;   /* 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 static void __init ms_hyperv_init_platform(void)
 204 {
 205         int hv_host_info_eax;
 206         int hv_host_info_ebx;
 207         int hv_host_info_ecx;
 208         int hv_host_info_edx;
 209
 210         /*
 211          * Extract the features and hints
 212          */
 213         ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
 214         ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
 215         ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
 216
 217         pr_info("Hyper-V: features 0x%x, hints 0x%x, misc 0x%x\n",
 218                 ms_hyperv.features, ms_hyperv.hints, ms_hyperv.misc_features);
 219
 220         ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS);
 221         ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS);
 222
 223         pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n",
 224                  ms_hyperv.max_vp_index, ms_hyperv.max_lp_index);
 225
 226         /*
 227          * Extract host information.
 228          */
 229         if (cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS) >=
 230             HYPERV_CPUID_VERSION) {
 231                 hv_host_info_eax = cpuid_eax(HYPERV_CPUID_VERSION);
 232                 hv_host_info_ebx = cpuid_ebx(HYPERV_CPUID_VERSION);
 233                 hv_host_info_ecx = cpuid_ecx(HYPERV_CPUID_VERSION);
 234                 hv_host_info_edx = cpuid_edx(HYPERV_CPUID_VERSION);
 235
 236                 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n",
 237                         hv_host_info_eax, hv_host_info_ebx >> 16,
 238                         hv_host_info_ebx & 0xFFFF, hv_host_info_ecx,
 239                         hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF);
 240         }
 241
 242         if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
 243             ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
 244                 x86_platform.calibrate_tsc = hv_get_tsc_khz;
 245                 x86_platform.calibrate_cpu = hv_get_tsc_khz;
 246         }
 247
 248         if (ms_hyperv.hints & HV_X64_ENLIGHTENED_VMCS_RECOMMENDED) {
 249                 ms_hyperv.nested_features =
 250                         cpuid_eax(HYPERV_CPUID_NESTED_FEATURES);
 251         }
 252
 253         /*
 254          * Hyper-V expects to get crash register data or kmsg when
 255          * crash enlightment is available and system crashes. Set
 256          * crash_kexec_post_notifiers to be true to make sure that
 257          * calling crash enlightment interface before running kdump
 258          * kernel.
 259          */
 260         if (ms_hyperv.misc_features & HV_FEATURE_GUEST_CRASH_MSR_AVAILABLE)
 261                 crash_kexec_post_notifiers = true;
 262
 263 #ifdef CONFIG_X86_LOCAL_APIC
 264         if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
 265             ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
 266                 /*
 267                  * Get the APIC frequency.
 268                  */
 269                 u64     hv_lapic_frequency;
 270
 271                 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency);
 272                 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ);
 273                 lapic_timer_frequency = hv_lapic_frequency;
 274                 pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n",
 275                         lapic_timer_frequency);
 276         }
 277
 278         register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST,
 279                              "hv_nmi_unknown");
 280 #endif
 281
 282 #ifdef CONFIG_X86_IO_APIC
 283         no_timer_check = 1;
 284 #endif
 285
 286 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE)
 287         machine_ops.shutdown = hv_machine_shutdown;
 288         machine_ops.crash_shutdown = hv_machine_crash_shutdown;
 289 #endif
 290         mark_tsc_unstable("running on Hyper-V");
 291
 292         /*
 293          * Generation 2 instances don't support reading the NMI status from
 294          * 0x61 port.
 295          */
 296         if (efi_enabled(EFI_BOOT))
 297                 x86_platform.get_nmi_reason = hv_get_nmi_reason;
 298
 299         /*
 300          * Hyper-V VMs have a PIT emulation quirk such that zeroing the
 301          * counter register during PIT shutdown restarts the PIT. So it
 302          * continues to interrupt @18.2 HZ. Setting i8253_clear_counter
 303          * to false tells pit_shutdown() not to zero the counter so that
 304          * the PIT really is shutdown. Generation 2 VMs don't have a PIT,
 305          * and setting this value has no effect.
 306          */
 307         i8253_clear_counter_on_shutdown = false;
 308
 309 #if IS_ENABLED(CONFIG_HYPERV)
 310         /*
 311          * Setup the hook to get control post apic initialization.
 312          */
 313         x86_platform.apic_post_init = hyperv_init;
 314         hyperv_setup_mmu_ops();
 315         /* Setup the IDT for hypervisor callback */
 316         alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
 317
 318         /* Setup the IDT for reenlightenment notifications */
 319         if (ms_hyperv.features & HV_X64_ACCESS_REENLIGHTENMENT)
 320                 alloc_intr_gate(HYPERV_REENLIGHTENMENT_VECTOR,
 321                                 hyperv_reenlightenment_vector);
 322
 323         /* Setup the IDT for stimer0 */
 324         if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE)
 325                 alloc_intr_gate(HYPERV_STIMER0_VECTOR,
 326                                 hv_stimer0_callback_vector);
 327 #endif
 328 }
 329
 330 const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
 331         .name                   = "Microsoft Hyper-V",
 332         .detect                 = ms_hyperv_platform,
 333         .type                   = X86_HYPER_MS_HYPERV,
 334         .init.init_platform     = ms_hyperv_init_platform,
 335 };