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-tlfs.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_stimer0_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 /*
  74  * Routines to do per-architecture handling of stimer0
  75  * interrupts when in Direct Mode
  76  */
  77
  78 __visible void __irq_entry hv_stimer0_vector_handler(struct pt_regs *regs)
  79 {
  80         struct pt_regs *old_regs = set_irq_regs(regs);
  81
  82         entering_irq();
  83         inc_irq_stat(hyperv_stimer0_count);
  84         if (hv_stimer0_handler)
  85                 hv_stimer0_handler();
  86         ack_APIC_irq();
  87
  88         exiting_irq();
  89         set_irq_regs(old_regs);
  90 }
  91
  92 int hv_setup_stimer0_irq(int *irq, int *vector, void (*handler)(void))
  93 {
  94         *vector = HYPERV_STIMER0_VECTOR;
  95         *irq = 0;   /* Unused on x86/x64 */
  96         hv_stimer0_handler = handler;
  97         return 0;
  98 }
  99 EXPORT_SYMBOL_GPL(hv_setup_stimer0_irq);
 100
 101 void hv_remove_stimer0_irq(int irq)
 102 {
 103         /* We have no way to deallocate the interrupt gate */
 104         hv_stimer0_handler = NULL;
 105 }
 106 EXPORT_SYMBOL_GPL(hv_remove_stimer0_irq);
 107
 108 void hv_setup_kexec_handler(void (*handler)(void))
 109 {
 110         hv_kexec_handler = handler;
 111 }
 112 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler);
 113
 114 void hv_remove_kexec_handler(void)
 115 {
 116         hv_kexec_handler = NULL;
 117 }
 118 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler);
 119
 120 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs))
 121 {
 122         hv_crash_handler = handler;
 123 }
 124 EXPORT_SYMBOL_GPL(hv_setup_crash_handler);
 125
 126 void hv_remove_crash_handler(void)
 127 {
 128         hv_crash_handler = NULL;
 129 }
 130 EXPORT_SYMBOL_GPL(hv_remove_crash_handler);
 131
 132 #ifdef CONFIG_KEXEC_CORE
 133 static void hv_machine_shutdown(void)
 134 {
 135         if (kexec_in_progress && hv_kexec_handler)
 136                 hv_kexec_handler();
 137         native_machine_shutdown();
 138 }
 139
 140 static void hv_machine_crash_shutdown(struct pt_regs *regs)
 141 {
 142         if (hv_crash_handler)
 143                 hv_crash_handler(regs);
 144         native_machine_crash_shutdown(regs);
 145 }
 146 #endif /* CONFIG_KEXEC_CORE */
 147 #endif /* CONFIG_HYPERV */
 148
 149 static uint32_t  __init ms_hyperv_platform(void)
 150 {
 151         u32 eax;
 152         u32 hyp_signature[3];
 153
 154         if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
 155                 return 0;
 156
 157         cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
 158               &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
 159
 160         if (eax >= HYPERV_CPUID_MIN &&
 161             eax <= HYPERV_CPUID_MAX &&
 162             !memcmp("Microsoft Hv", hyp_signature, 12))
 163                 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS;
 164
 165         return 0;
 166 }
 167
 168 static unsigned char hv_get_nmi_reason(void)
 169 {
 170         return 0;
 171 }
 172
 173 #ifdef CONFIG_X86_LOCAL_APIC
 174 /*
 175  * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes
 176  * it dificult to process CHANNELMSG_UNLOAD in case of crash. Handle
 177  * unknown NMI on the first CPU which gets it.
 178  */
 179 static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs)
 180 {
 181         static atomic_t nmi_cpu = ATOMIC_INIT(-1);
 182
 183         if (!unknown_nmi_panic)
 184                 return NMI_DONE;
 185
 186         if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1)
 187                 return NMI_HANDLED;
 188
 189         return NMI_DONE;
 190 }
 191 #endif
 192
 193 static unsigned long hv_get_tsc_khz(void)
 194 {
 195         unsigned long freq;
 196
 197         rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
 198
 199         return freq / 1000;
 200 }
 201
 202 static void __init ms_hyperv_init_platform(void)
 203 {
 204         int hv_host_info_eax;
 205         int hv_host_info_ebx;
 206         int hv_host_info_ecx;
 207         int hv_host_info_edx;
 208
 209         /*
 210          * Extract the features and hints
 211          */
 212         ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
 213         ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
 214         ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
 215
 216         pr_info("Hyper-V: features 0x%x, hints 0x%x\n",
 217                 ms_hyperv.features, ms_hyperv.hints);
 218
 219         ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS);
 220         ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS);
 221
 222         pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n",
 223                  ms_hyperv.max_vp_index, ms_hyperv.max_lp_index);
 224
 225         /*
 226          * Extract host information.
 227          */
 228         if (cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS) >=
 229             HYPERV_CPUID_VERSION) {
 230                 hv_host_info_eax = cpuid_eax(HYPERV_CPUID_VERSION);
 231                 hv_host_info_ebx = cpuid_ebx(HYPERV_CPUID_VERSION);
 232                 hv_host_info_ecx = cpuid_ecx(HYPERV_CPUID_VERSION);
 233                 hv_host_info_edx = cpuid_edx(HYPERV_CPUID_VERSION);
 234
 235                 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n",
 236                         hv_host_info_eax, hv_host_info_ebx >> 16,
 237                         hv_host_info_ebx & 0xFFFF, hv_host_info_ecx,
 238                         hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF);
 239         }
 240
 241         if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
 242             ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
 243                 x86_platform.calibrate_tsc = hv_get_tsc_khz;
 244                 x86_platform.calibrate_cpu = hv_get_tsc_khz;
 245         }
 246
 247         if (ms_hyperv.hints & HV_X64_ENLIGHTENED_VMCS_RECOMMENDED) {
 248                 ms_hyperv.nested_features =
 249                         cpuid_eax(HYPERV_CPUID_NESTED_FEATURES);
 250         }
 251
 252 #ifdef CONFIG_X86_LOCAL_APIC
 253         if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
 254             ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
 255                 /*
 256                  * Get the APIC frequency.
 257                  */
 258                 u64     hv_lapic_frequency;
 259
 260                 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency);
 261                 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ);
 262                 lapic_timer_frequency = hv_lapic_frequency;
 263                 pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n",
 264                         lapic_timer_frequency);
 265         }
 266
 267         register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST,
 268                              "hv_nmi_unknown");
 269 #endif
 270
 271 #ifdef CONFIG_X86_IO_APIC
 272         no_timer_check = 1;
 273 #endif
 274
 275 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE)
 276         machine_ops.shutdown = hv_machine_shutdown;
 277         machine_ops.crash_shutdown = hv_machine_crash_shutdown;
 278 #endif
 279         mark_tsc_unstable("running on Hyper-V");
 280
 281         /*
 282          * Generation 2 instances don't support reading the NMI status from
 283          * 0x61 port.
 284          */
 285         if (efi_enabled(EFI_BOOT))
 286                 x86_platform.get_nmi_reason = hv_get_nmi_reason;
 287
 288 #if IS_ENABLED(CONFIG_HYPERV)
 289         /*
 290          * Setup the hook to get control post apic initialization.
 291          */
 292         x86_platform.apic_post_init = hyperv_init;
 293         hyperv_setup_mmu_ops();
 294         /* Setup the IDT for hypervisor callback */
 295         alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
 296
 297         /* Setup the IDT for reenlightenment notifications */
 298         if (ms_hyperv.features & HV_X64_ACCESS_REENLIGHTENMENT)
 299                 alloc_intr_gate(HYPERV_REENLIGHTENMENT_VECTOR,
 300                                 hyperv_reenlightenment_vector);
 301
 302         /* Setup the IDT for stimer0 */
 303         if (ms_hyperv.misc_features & HV_X64_STIMER_DIRECT_MODE_AVAILABLE)
 304                 alloc_intr_gate(HYPERV_STIMER0_VECTOR,
 305                                 hv_stimer0_callback_vector);
 306 #endif
 307 }
 308
 309 const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
 310         .name                   = "Microsoft Hyper-V",
 311         .detect                 = ms_hyperv_platform,
 312         .type                   = X86_HYPER_MS_HYPERV,
 313         .init.init_platform     = ms_hyperv_init_platform,
 314 };