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.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_kexec_handler)(void);
  42 static void (*hv_crash_handler)(struct pt_regs *regs);
  43
  44 void hyperv_vector_handler(struct pt_regs *regs)
  45 {
  46         struct pt_regs *old_regs = set_irq_regs(regs);
  47
  48         entering_irq();
  49         inc_irq_stat(irq_hv_callback_count);
  50         if (vmbus_handler)
  51                 vmbus_handler();
  52
  53         if (ms_hyperv.hints & HV_X64_DEPRECATING_AEOI_RECOMMENDED)
  54                 ack_APIC_irq();
  55
  56         exiting_irq();
  57         set_irq_regs(old_regs);
  58 }
  59
  60 void hv_setup_vmbus_irq(void (*handler)(void))
  61 {
  62         vmbus_handler = handler;
  63 }
  64
  65 void hv_remove_vmbus_irq(void)
  66 {
  67         /* We have no way to deallocate the interrupt gate */
  68         vmbus_handler = NULL;
  69 }
  70 EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq);
  71 EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq);
  72
  73 void hv_setup_kexec_handler(void (*handler)(void))
  74 {
  75         hv_kexec_handler = handler;
  76 }
  77 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler);
  78
  79 void hv_remove_kexec_handler(void)
  80 {
  81         hv_kexec_handler = NULL;
  82 }
  83 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler);
  84
  85 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs))
  86 {
  87         hv_crash_handler = handler;
  88 }
  89 EXPORT_SYMBOL_GPL(hv_setup_crash_handler);
  90
  91 void hv_remove_crash_handler(void)
  92 {
  93         hv_crash_handler = NULL;
  94 }
  95 EXPORT_SYMBOL_GPL(hv_remove_crash_handler);
  96
  97 #ifdef CONFIG_KEXEC_CORE
  98 static void hv_machine_shutdown(void)
  99 {
 100         if (kexec_in_progress && hv_kexec_handler)
 101                 hv_kexec_handler();
 102         native_machine_shutdown();
 103 }
 104
 105 static void hv_machine_crash_shutdown(struct pt_regs *regs)
 106 {
 107         if (hv_crash_handler)
 108                 hv_crash_handler(regs);
 109         native_machine_crash_shutdown(regs);
 110 }
 111 #endif /* CONFIG_KEXEC_CORE */
 112 #endif /* CONFIG_HYPERV */
 113
 114 static uint32_t  __init ms_hyperv_platform(void)
 115 {
 116         u32 eax;
 117         u32 hyp_signature[3];
 118
 119         if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
 120                 return 0;
 121
 122         cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
 123               &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
 124
 125         if (eax >= HYPERV_CPUID_MIN &&
 126             eax <= HYPERV_CPUID_MAX &&
 127             !memcmp("Microsoft Hv", hyp_signature, 12))
 128                 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS;
 129
 130         return 0;
 131 }
 132
 133 static unsigned char hv_get_nmi_reason(void)
 134 {
 135         return 0;
 136 }
 137
 138 #ifdef CONFIG_X86_LOCAL_APIC
 139 /*
 140  * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes
 141  * it dificult to process CHANNELMSG_UNLOAD in case of crash. Handle
 142  * unknown NMI on the first CPU which gets it.
 143  */
 144 static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs)
 145 {
 146         static atomic_t nmi_cpu = ATOMIC_INIT(-1);
 147
 148         if (!unknown_nmi_panic)
 149                 return NMI_DONE;
 150
 151         if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1)
 152                 return NMI_HANDLED;
 153
 154         return NMI_DONE;
 155 }
 156 #endif
 157
 158 static unsigned long hv_get_tsc_khz(void)
 159 {
 160         unsigned long freq;
 161
 162         rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
 163
 164         return freq / 1000;
 165 }
 166
 167 static void __init ms_hyperv_init_platform(void)
 168 {
 169         int hv_host_info_eax;
 170         int hv_host_info_ebx;
 171         int hv_host_info_ecx;
 172         int hv_host_info_edx;
 173
 174         /*
 175          * Extract the features and hints
 176          */
 177         ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
 178         ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
 179         ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
 180
 181         pr_info("Hyper-V: features 0x%x, hints 0x%x\n",
 182                 ms_hyperv.features, ms_hyperv.hints);
 183
 184         ms_hyperv.max_vp_index = cpuid_eax(HVCPUID_IMPLEMENTATION_LIMITS);
 185         ms_hyperv.max_lp_index = cpuid_ebx(HVCPUID_IMPLEMENTATION_LIMITS);
 186
 187         pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n",
 188                  ms_hyperv.max_vp_index, ms_hyperv.max_lp_index);
 189
 190         /*
 191          * Extract host information.
 192          */
 193         if (cpuid_eax(HVCPUID_VENDOR_MAXFUNCTION) >= HVCPUID_VERSION) {
 194                 hv_host_info_eax = cpuid_eax(HVCPUID_VERSION);
 195                 hv_host_info_ebx = cpuid_ebx(HVCPUID_VERSION);
 196                 hv_host_info_ecx = cpuid_ecx(HVCPUID_VERSION);
 197                 hv_host_info_edx = cpuid_edx(HVCPUID_VERSION);
 198
 199                 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n",
 200                         hv_host_info_eax, hv_host_info_ebx >> 16,
 201                         hv_host_info_ebx & 0xFFFF, hv_host_info_ecx,
 202                         hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF);
 203         }
 204
 205         if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
 206             ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
 207                 x86_platform.calibrate_tsc = hv_get_tsc_khz;
 208                 x86_platform.calibrate_cpu = hv_get_tsc_khz;
 209         }
 210
 211 #ifdef CONFIG_X86_LOCAL_APIC
 212         if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
 213             ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
 214                 /*
 215                  * Get the APIC frequency.
 216                  */
 217                 u64     hv_lapic_frequency;
 218
 219                 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency);
 220                 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ);
 221                 lapic_timer_frequency = hv_lapic_frequency;
 222                 pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n",
 223                         lapic_timer_frequency);
 224         }
 225
 226         register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST,
 227                              "hv_nmi_unknown");
 228 #endif
 229
 230 #ifdef CONFIG_X86_IO_APIC
 231         no_timer_check = 1;
 232 #endif
 233
 234 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE)
 235         machine_ops.shutdown = hv_machine_shutdown;
 236         machine_ops.crash_shutdown = hv_machine_crash_shutdown;
 237 #endif
 238         mark_tsc_unstable("running on Hyper-V");
 239
 240         /*
 241          * Generation 2 instances don't support reading the NMI status from
 242          * 0x61 port.
 243          */
 244         if (efi_enabled(EFI_BOOT))
 245                 x86_platform.get_nmi_reason = hv_get_nmi_reason;
 246
 247         /*
 248          * Hyper-V VMs have a PIT emulation quirk such that zeroing the
 249          * counter register during PIT shutdown restarts the PIT. So it
 250          * continues to interrupt @18.2 HZ. Setting i8253_clear_counter
 251          * to false tells pit_shutdown() not to zero the counter so that
 252          * the PIT really is shutdown. Generation 2 VMs don't have a PIT,
 253          * and setting this value has no effect.
 254          */
 255         i8253_clear_counter_on_shutdown = false;
 256
 257 #if IS_ENABLED(CONFIG_HYPERV)
 258         /*
 259          * Setup the hook to get control post apic initialization.
 260          */
 261         x86_platform.apic_post_init = hyperv_init;
 262         hyperv_setup_mmu_ops();
 263         /* Setup the IDT for hypervisor callback */
 264         alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
 265 #endif
 266 }
 267
 268 const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
 269         .name                   = "Microsoft Hyper-V",
 270         .detect                 = ms_hyperv_platform,
 271         .type                   = X86_HYPER_MS_HYPERV,
 272         .init.init_platform     = ms_hyperv_init_platform,
 273 };