arch/x86/kernel/cpu/mshyperv.c

   1 /*
   2  * HyperV  Detection code.
   3  *
   4  * Copyright (C) 2010, Novell, Inc.
   5  * Author : K. Y. Srinivasan <[email protected]>
   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         /* Setup the IDT for hypervisor callback */
  63         alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
  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 void hv_setup_kexec_handler(void (*handler)(void))
  75 {
  76         hv_kexec_handler = handler;
  77 }
  78 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler);
  79
  80 void hv_remove_kexec_handler(void)
  81 {
  82         hv_kexec_handler = NULL;
  83 }
  84 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler);
  85
  86 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs))
  87 {
  88         hv_crash_handler = handler;
  89 }
  90 EXPORT_SYMBOL_GPL(hv_setup_crash_handler);
  91
  92 void hv_remove_crash_handler(void)
  93 {
  94         hv_crash_handler = NULL;
  95 }
  96 EXPORT_SYMBOL_GPL(hv_remove_crash_handler);
  97
  98 #ifdef CONFIG_KEXEC_CORE
  99 static void hv_machine_shutdown(void)
 100 {
 101         if (kexec_in_progress && hv_kexec_handler)
 102                 hv_kexec_handler();
 103         native_machine_shutdown();
 104 }
 105
 106 static void hv_machine_crash_shutdown(struct pt_regs *regs)
 107 {
 108         if (hv_crash_handler)
 109                 hv_crash_handler(regs);
 110         native_machine_crash_shutdown(regs);
 111 }
 112 #endif /* CONFIG_KEXEC_CORE */
 113 #endif /* CONFIG_HYPERV */
 114
 115 static uint32_t  __init ms_hyperv_platform(void)
 116 {
 117         u32 eax;
 118         u32 hyp_signature[3];
 119
 120         if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
 121                 return 0;
 122
 123         cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
 124               &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
 125
 126         if (eax >= HYPERV_CPUID_MIN &&
 127             eax <= HYPERV_CPUID_MAX &&
 128             !memcmp("Microsoft Hv", hyp_signature, 12))
 129                 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS;
 130
 131         return 0;
 132 }
 133
 134 static unsigned char hv_get_nmi_reason(void)
 135 {
 136         return 0;
 137 }
 138
 139 #ifdef CONFIG_X86_LOCAL_APIC
 140 /*
 141  * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes
 142  * it dificult to process CHANNELMSG_UNLOAD in case of crash. Handle
 143  * unknown NMI on the first CPU which gets it.
 144  */
 145 static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs)
 146 {
 147         static atomic_t nmi_cpu = ATOMIC_INIT(-1);
 148
 149         if (!unknown_nmi_panic)
 150                 return NMI_DONE;
 151
 152         if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1)
 153                 return NMI_HANDLED;
 154
 155         return NMI_DONE;
 156 }
 157 #endif
 158
 159 static unsigned long hv_get_tsc_khz(void)
 160 {
 161         unsigned long freq;
 162
 163         rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
 164
 165         return freq / 1000;
 166 }
 167
 168 static void __init ms_hyperv_init_platform(void)
 169 {
 170         int hv_host_info_eax;
 171         int hv_host_info_ebx;
 172         int hv_host_info_ecx;
 173         int hv_host_info_edx;
 174
 175         /*
 176          * Extract the features and hints
 177          */
 178         ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
 179         ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
 180         ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
 181
 182         pr_info("Hyper-V: features 0x%x, hints 0x%x\n",
 183                 ms_hyperv.features, ms_hyperv.hints);
 184
 185         ms_hyperv.max_vp_index = cpuid_eax(HVCPUID_IMPLEMENTATION_LIMITS);
 186         ms_hyperv.max_lp_index = cpuid_ebx(HVCPUID_IMPLEMENTATION_LIMITS);
 187
 188         pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n",
 189                  ms_hyperv.max_vp_index, ms_hyperv.max_lp_index);
 190
 191         /*
 192          * Extract host information.
 193          */
 194         if (cpuid_eax(HVCPUID_VENDOR_MAXFUNCTION) >= HVCPUID_VERSION) {
 195                 hv_host_info_eax = cpuid_eax(HVCPUID_VERSION);
 196                 hv_host_info_ebx = cpuid_ebx(HVCPUID_VERSION);
 197                 hv_host_info_ecx = cpuid_ecx(HVCPUID_VERSION);
 198                 hv_host_info_edx = cpuid_edx(HVCPUID_VERSION);
 199
 200                 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n",
 201                         hv_host_info_eax, hv_host_info_ebx >> 16,
 202                         hv_host_info_ebx & 0xFFFF, hv_host_info_ecx,
 203                         hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF);
 204         }
 205
 206         if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
 207             ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
 208                 x86_platform.calibrate_tsc = hv_get_tsc_khz;
 209                 x86_platform.calibrate_cpu = hv_get_tsc_khz;
 210         }
 211
 212 #ifdef CONFIG_X86_LOCAL_APIC
 213         if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
 214             ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
 215                 /*
 216                  * Get the APIC frequency.
 217                  */
 218                 u64     hv_lapic_frequency;
 219
 220                 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency);
 221                 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ);
 222                 lapic_timer_frequency = hv_lapic_frequency;
 223                 pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n",
 224                         lapic_timer_frequency);
 225         }
 226
 227         register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST,
 228                              "hv_nmi_unknown");
 229 #endif
 230
 231 #ifdef CONFIG_X86_IO_APIC
 232         no_timer_check = 1;
 233 #endif
 234
 235 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE)
 236         machine_ops.shutdown = hv_machine_shutdown;
 237         machine_ops.crash_shutdown = hv_machine_crash_shutdown;
 238 #endif
 239         mark_tsc_unstable("running on Hyper-V");
 240
 241         /*
 242          * Generation 2 instances don't support reading the NMI status from
 243          * 0x61 port.
 244          */
 245         if (efi_enabled(EFI_BOOT))
 246                 x86_platform.get_nmi_reason = hv_get_nmi_reason;
 247
 248 #if IS_ENABLED(CONFIG_HYPERV)
 249         /*
 250          * Setup the hook to get control post apic initialization.
 251          */
 252         x86_platform.apic_post_init = hyperv_init;
 253         hyperv_setup_mmu_ops();
 254 #endif
 255 }
 256
 257 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
 258         .name                   = "Microsoft Hyper-V",
 259         .detect                 = ms_hyperv_platform,
 260         .init_platform          = ms_hyperv_init_platform,
 261 };
 262 EXPORT_SYMBOL(x86_hyper_ms_hyperv);