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 <asm/processor.h>
  24 #include <asm/hypervisor.h>
  25 #include <asm/hyperv.h>
  26 #include <asm/mshyperv.h>
  27 #include <asm/desc.h>
  28 #include <asm/irq_regs.h>
  29 #include <asm/i8259.h>
  30 #include <asm/apic.h>
  31 #include <asm/timer.h>
  32 #include <asm/reboot.h>
  33 #include <asm/nmi.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_kexec_handler)(void);
  41 static void (*hv_crash_handler)(struct pt_regs *regs);
  42
  43 void hyperv_vector_handler(struct pt_regs *regs)
  44 {
  45         struct pt_regs *old_regs = set_irq_regs(regs);
  46
  47         entering_irq();
  48         inc_irq_stat(irq_hv_callback_count);
  49         if (vmbus_handler)
  50                 vmbus_handler();
  51
  52         if (ms_hyperv.hints & HV_X64_DEPRECATING_AEOI_RECOMMENDED)
  53                 ack_APIC_irq();
  54
  55         exiting_irq();
  56         set_irq_regs(old_regs);
  57 }
  58
  59 void hv_setup_vmbus_irq(void (*handler)(void))
  60 {
  61         vmbus_handler = handler;
  62 }
  63
  64 void hv_remove_vmbus_irq(void)
  65 {
  66         /* We have no way to deallocate the interrupt gate */
  67         vmbus_handler = NULL;
  68 }
  69 EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq);
  70 EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq);
  71
  72 void hv_setup_kexec_handler(void (*handler)(void))
  73 {
  74         hv_kexec_handler = handler;
  75 }
  76 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler);
  77
  78 void hv_remove_kexec_handler(void)
  79 {
  80         hv_kexec_handler = NULL;
  81 }
  82 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler);
  83
  84 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs))
  85 {
  86         hv_crash_handler = handler;
  87 }
  88 EXPORT_SYMBOL_GPL(hv_setup_crash_handler);
  89
  90 void hv_remove_crash_handler(void)
  91 {
  92         hv_crash_handler = NULL;
  93 }
  94 EXPORT_SYMBOL_GPL(hv_remove_crash_handler);
  95
  96 #ifdef CONFIG_KEXEC_CORE
  97 static void hv_machine_shutdown(void)
  98 {
  99         if (kexec_in_progress && hv_kexec_handler)
 100                 hv_kexec_handler();
 101         native_machine_shutdown();
 102 }
 103
 104 static void hv_machine_crash_shutdown(struct pt_regs *regs)
 105 {
 106         if (hv_crash_handler)
 107                 hv_crash_handler(regs);
 108         native_machine_crash_shutdown(regs);
 109 }
 110 #endif /* CONFIG_KEXEC_CORE */
 111 #endif /* CONFIG_HYPERV */
 112
 113 static uint32_t  __init ms_hyperv_platform(void)
 114 {
 115         u32 eax;
 116         u32 hyp_signature[3];
 117
 118         if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
 119                 return 0;
 120
 121         cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
 122               &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
 123
 124         if (eax >= HYPERV_CPUID_MIN &&
 125             eax <= HYPERV_CPUID_MAX &&
 126             !memcmp("Microsoft Hv", hyp_signature, 12))
 127                 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS;
 128
 129         return 0;
 130 }
 131
 132 static unsigned char hv_get_nmi_reason(void)
 133 {
 134         return 0;
 135 }
 136
 137 #ifdef CONFIG_X86_LOCAL_APIC
 138 /*
 139  * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes
 140  * it dificult to process CHANNELMSG_UNLOAD in case of crash. Handle
 141  * unknown NMI on the first CPU which gets it.
 142  */
 143 static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs)
 144 {
 145         static atomic_t nmi_cpu = ATOMIC_INIT(-1);
 146
 147         if (!unknown_nmi_panic)
 148                 return NMI_DONE;
 149
 150         if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1)
 151                 return NMI_HANDLED;
 152
 153         return NMI_DONE;
 154 }
 155 #endif
 156
 157 static unsigned long hv_get_tsc_khz(void)
 158 {
 159         unsigned long freq;
 160
 161         rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
 162
 163         return freq / 1000;
 164 }
 165
 166 static void __init ms_hyperv_init_platform(void)
 167 {
 168         int hv_host_info_eax;
 169         int hv_host_info_ebx;
 170         int hv_host_info_ecx;
 171         int hv_host_info_edx;
 172
 173         /*
 174          * Extract the features and hints
 175          */
 176         ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
 177         ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
 178         ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
 179
 180         pr_info("Hyper-V: features 0x%x, hints 0x%x\n",
 181                 ms_hyperv.features, ms_hyperv.hints);
 182
 183         ms_hyperv.max_vp_index = cpuid_eax(HVCPUID_IMPLEMENTATION_LIMITS);
 184         ms_hyperv.max_lp_index = cpuid_ebx(HVCPUID_IMPLEMENTATION_LIMITS);
 185
 186         pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n",
 187                  ms_hyperv.max_vp_index, ms_hyperv.max_lp_index);
 188
 189         /*
 190          * Extract host information.
 191          */
 192         if (cpuid_eax(HVCPUID_VENDOR_MAXFUNCTION) >= HVCPUID_VERSION) {
 193                 hv_host_info_eax = cpuid_eax(HVCPUID_VERSION);
 194                 hv_host_info_ebx = cpuid_ebx(HVCPUID_VERSION);
 195                 hv_host_info_ecx = cpuid_ecx(HVCPUID_VERSION);
 196                 hv_host_info_edx = cpuid_edx(HVCPUID_VERSION);
 197
 198                 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n",
 199                         hv_host_info_eax, hv_host_info_ebx >> 16,
 200                         hv_host_info_ebx & 0xFFFF, hv_host_info_ecx,
 201                         hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF);
 202         }
 203
 204         if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
 205             ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
 206                 x86_platform.calibrate_tsc = hv_get_tsc_khz;
 207                 x86_platform.calibrate_cpu = hv_get_tsc_khz;
 208         }
 209
 210 #ifdef CONFIG_X86_LOCAL_APIC
 211         if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
 212             ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
 213                 /*
 214                  * Get the APIC frequency.
 215                  */
 216                 u64     hv_lapic_frequency;
 217
 218                 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency);
 219                 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ);
 220                 lapic_timer_frequency = hv_lapic_frequency;
 221                 pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n",
 222                         lapic_timer_frequency);
 223         }
 224
 225         register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST,
 226                              "hv_nmi_unknown");
 227 #endif
 228
 229 #ifdef CONFIG_X86_IO_APIC
 230         no_timer_check = 1;
 231 #endif
 232
 233 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE)
 234         machine_ops.shutdown = hv_machine_shutdown;
 235         machine_ops.crash_shutdown = hv_machine_crash_shutdown;
 236 #endif
 237         mark_tsc_unstable("running on Hyper-V");
 238
 239         /*
 240          * Generation 2 instances don't support reading the NMI status from
 241          * 0x61 port.
 242          */
 243         if (efi_enabled(EFI_BOOT))
 244                 x86_platform.get_nmi_reason = hv_get_nmi_reason;
 245
 246 #if IS_ENABLED(CONFIG_HYPERV)
 247         /*
 248          * Setup the hook to get control post apic initialization.
 249          */
 250         x86_platform.apic_post_init = hyperv_init;
 251         hyperv_setup_mmu_ops();
 252         /* Setup the IDT for hypervisor callback */
 253         alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
 254 #endif
 255 }
 256
 257 const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
 258         .name                   = "Microsoft Hyper-V",
 259         .detect                 = ms_hyperv_platform,
 260         .type                   = X86_HYPER_MS_HYPERV,
 261         .init.init_platform     = ms_hyperv_init_platform,
 262 };