arch/x86/kernel/cpu/mshyperv.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * HyperV  Detection code.
   4  *
   5  * Copyright (C) 2010, Novell, Inc.
   6  * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
   7  */
   8
   9 #include <linux/types.h>
  10 #include <linux/time.h>
  11 #include <linux/clocksource.h>
  12 #include <linux/init.h>
  13 #include <linux/export.h>
  14 #include <linux/hardirq.h>
  15 #include <linux/efi.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/irq.h>
  18 #include <linux/kexec.h>
  19 #include <linux/i8253.h>
  20 #include <asm/processor.h>
  21 #include <asm/hypervisor.h>
  22 #include <asm/hyperv-tlfs.h>
  23 #include <asm/mshyperv.h>
  24 #include <asm/desc.h>
  25 #include <asm/irq_regs.h>
  26 #include <asm/i8259.h>
  27 #include <asm/apic.h>
  28 #include <asm/timer.h>
  29 #include <asm/reboot.h>
  30 #include <asm/nmi.h>
  31
  32 struct ms_hyperv_info ms_hyperv;
  33 EXPORT_SYMBOL_GPL(ms_hyperv);
  34
  35 #if IS_ENABLED(CONFIG_HYPERV)
  36 static void (*vmbus_handler)(void);
  37 static void (*hv_stimer0_handler)(void);
  38 static void (*hv_kexec_handler)(void);
  39 static void (*hv_crash_handler)(struct pt_regs *regs);
  40
  41 __visible void __irq_entry hyperv_vector_handler(struct pt_regs *regs)
  42 {
  43         struct pt_regs *old_regs = set_irq_regs(regs);
  44
  45         entering_irq();
  46         inc_irq_stat(irq_hv_callback_count);
  47         if (vmbus_handler)
  48                 vmbus_handler();
  49
  50         if (ms_hyperv.hints & HV_DEPRECATING_AEOI_RECOMMENDED)
  51                 ack_APIC_irq();
  52
  53         exiting_irq();
  54         set_irq_regs(old_regs);
  55 }
  56
  57 void hv_setup_vmbus_irq(void (*handler)(void))
  58 {
  59         vmbus_handler = handler;
  60 }
  61
  62 void hv_remove_vmbus_irq(void)
  63 {
  64         /* We have no way to deallocate the interrupt gate */
  65         vmbus_handler = NULL;
  66 }
  67 EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq);
  68 EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq);
  69
  70 /*
  71  * Routines to do per-architecture handling of stimer0
  72  * interrupts when in Direct Mode
  73  */
  74
  75 __visible void __irq_entry hv_stimer0_vector_handler(struct pt_regs *regs)
  76 {
  77         struct pt_regs *old_regs = set_irq_regs(regs);
  78
  79         entering_irq();
  80         inc_irq_stat(hyperv_stimer0_count);
  81         if (hv_stimer0_handler)
  82                 hv_stimer0_handler();
  83         ack_APIC_irq();
  84
  85         exiting_irq();
  86         set_irq_regs(old_regs);
  87 }
  88
  89 int hv_setup_stimer0_irq(int *irq, int *vector, void (*handler)(void))
  90 {
  91         *vector = HYPERV_STIMER0_VECTOR;
  92         *irq = 0;   /* Unused on x86/x64 */
  93         hv_stimer0_handler = handler;
  94         return 0;
  95 }
  96 EXPORT_SYMBOL_GPL(hv_setup_stimer0_irq);
  97
  98 void hv_remove_stimer0_irq(int irq)
  99 {
 100         /* We have no way to deallocate the interrupt gate */
 101         hv_stimer0_handler = NULL;
 102 }
 103 EXPORT_SYMBOL_GPL(hv_remove_stimer0_irq);
 104
 105 void hv_setup_kexec_handler(void (*handler)(void))
 106 {
 107         hv_kexec_handler = handler;
 108 }
 109 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler);
 110
 111 void hv_remove_kexec_handler(void)
 112 {
 113         hv_kexec_handler = NULL;
 114 }
 115 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler);
 116
 117 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs))
 118 {
 119         hv_crash_handler = handler;
 120 }
 121 EXPORT_SYMBOL_GPL(hv_setup_crash_handler);
 122
 123 void hv_remove_crash_handler(void)
 124 {
 125         hv_crash_handler = NULL;
 126 }
 127 EXPORT_SYMBOL_GPL(hv_remove_crash_handler);
 128
 129 #ifdef CONFIG_KEXEC_CORE
 130 static void hv_machine_shutdown(void)
 131 {
 132         if (kexec_in_progress && hv_kexec_handler)
 133                 hv_kexec_handler();
 134         native_machine_shutdown();
 135 }
 136
 137 static void hv_machine_crash_shutdown(struct pt_regs *regs)
 138 {
 139         if (hv_crash_handler)
 140                 hv_crash_handler(regs);
 141         native_machine_crash_shutdown(regs);
 142 }
 143 #endif /* CONFIG_KEXEC_CORE */
 144 #endif /* CONFIG_HYPERV */
 145
 146 static uint32_t  __init ms_hyperv_platform(void)
 147 {
 148         u32 eax;
 149         u32 hyp_signature[3];
 150
 151         if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
 152                 return 0;
 153
 154         cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
 155               &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
 156
 157         if (eax >= HYPERV_CPUID_MIN &&
 158             eax <= HYPERV_CPUID_MAX &&
 159             !memcmp("Microsoft Hv", hyp_signature, 12))
 160                 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS;
 161
 162         return 0;
 163 }
 164
 165 static unsigned char hv_get_nmi_reason(void)
 166 {
 167         return 0;
 168 }
 169
 170 #ifdef CONFIG_X86_LOCAL_APIC
 171 /*
 172  * Prior to WS2016 Debug-VM sends NMIs to all CPUs which makes
 173  * it dificult to process CHANNELMSG_UNLOAD in case of crash. Handle
 174  * unknown NMI on the first CPU which gets it.
 175  */
 176 static int hv_nmi_unknown(unsigned int val, struct pt_regs *regs)
 177 {
 178         static atomic_t nmi_cpu = ATOMIC_INIT(-1);
 179
 180         if (!unknown_nmi_panic)
 181                 return NMI_DONE;
 182
 183         if (atomic_cmpxchg(&nmi_cpu, -1, raw_smp_processor_id()) != -1)
 184                 return NMI_HANDLED;
 185
 186         return NMI_DONE;
 187 }
 188 #endif
 189
 190 static unsigned long hv_get_tsc_khz(void)
 191 {
 192         unsigned long freq;
 193
 194         rdmsrl(HV_X64_MSR_TSC_FREQUENCY, freq);
 195
 196         return freq / 1000;
 197 }
 198
 199 #if defined(CONFIG_SMP) && IS_ENABLED(CONFIG_HYPERV)
 200 static void __init hv_smp_prepare_boot_cpu(void)
 201 {
 202         native_smp_prepare_boot_cpu();
 203 #if defined(CONFIG_X86_64) && defined(CONFIG_PARAVIRT_SPINLOCKS)
 204         hv_init_spinlocks();
 205 #endif
 206 }
 207 #endif
 208
 209 static void __init ms_hyperv_init_platform(void)
 210 {
 211         int hv_host_info_eax;
 212         int hv_host_info_ebx;
 213         int hv_host_info_ecx;
 214         int hv_host_info_edx;
 215
 216         /*
 217          * Extract the features and hints
 218          */
 219         ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
 220         ms_hyperv.misc_features = cpuid_edx(HYPERV_CPUID_FEATURES);
 221         ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
 222
 223         pr_info("Hyper-V: features 0x%x, hints 0x%x\n",
 224                 ms_hyperv.features, ms_hyperv.hints);
 225
 226         ms_hyperv.max_vp_index = cpuid_eax(HYPERV_CPUID_IMPLEMENT_LIMITS);
 227         ms_hyperv.max_lp_index = cpuid_ebx(HYPERV_CPUID_IMPLEMENT_LIMITS);
 228
 229         pr_debug("Hyper-V: max %u virtual processors, %u logical processors\n",
 230                  ms_hyperv.max_vp_index, ms_hyperv.max_lp_index);
 231
 232         /*
 233          * Extract host information.
 234          */
 235         if (cpuid_eax(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS) >=
 236             HYPERV_CPUID_VERSION) {
 237                 hv_host_info_eax = cpuid_eax(HYPERV_CPUID_VERSION);
 238                 hv_host_info_ebx = cpuid_ebx(HYPERV_CPUID_VERSION);
 239                 hv_host_info_ecx = cpuid_ecx(HYPERV_CPUID_VERSION);
 240                 hv_host_info_edx = cpuid_edx(HYPERV_CPUID_VERSION);
 241
 242                 pr_info("Hyper-V Host Build:%d-%d.%d-%d-%d.%d\n",
 243                         hv_host_info_eax, hv_host_info_ebx >> 16,
 244                         hv_host_info_ebx & 0xFFFF, hv_host_info_ecx,
 245                         hv_host_info_edx >> 24, hv_host_info_edx & 0xFFFFFF);
 246         }
 247
 248         if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
 249             ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
 250                 x86_platform.calibrate_tsc = hv_get_tsc_khz;
 251                 x86_platform.calibrate_cpu = hv_get_tsc_khz;
 252         }
 253
 254         if (ms_hyperv.hints & HV_X64_ENLIGHTENED_VMCS_RECOMMENDED) {
 255                 ms_hyperv.nested_features =
 256                         cpuid_eax(HYPERV_CPUID_NESTED_FEATURES);
 257         }
 258
 259 #ifdef CONFIG_X86_LOCAL_APIC
 260         if (ms_hyperv.features & HV_X64_ACCESS_FREQUENCY_MSRS &&
 261             ms_hyperv.misc_features & HV_FEATURE_FREQUENCY_MSRS_AVAILABLE) {
 262                 /*
 263                  * Get the APIC frequency.
 264                  */
 265                 u64     hv_lapic_frequency;
 266
 267                 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency);
 268                 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ);
 269                 lapic_timer_frequency = hv_lapic_frequency;
 270                 pr_info("Hyper-V: LAPIC Timer Frequency: %#x\n",
 271                         lapic_timer_frequency);
 272         }
 273
 274         register_nmi_handler(NMI_UNKNOWN, hv_nmi_unknown, NMI_FLAG_FIRST,
 275                              "hv_nmi_unknown");
 276 #endif
 277
 278 #ifdef CONFIG_X86_IO_APIC
 279         no_timer_check = 1;
 280 #endif
 281
 282 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE)
 283         machine_ops.shutdown = hv_machine_shutdown;
 284         machine_ops.crash_shutdown = hv_machine_crash_shutdown;
 285 #endif
 286         mark_tsc_unstable("running on Hyper-V");
 287
 288         /*
 289          * Generation 2 instances don't support reading the NMI status from
 290          * 0x61 port.
 291          */
 292         if (efi_enabled(EFI_BOOT))
 293                 x86_platform.get_nmi_reason = hv_get_nmi_reason;
 294
 295         /*
 296          * Hyper-V VMs have a PIT emulation quirk such that zeroing the
 297          * counter register during PIT shutdown restarts the PIT. So it
 298          * continues to interrupt @18.2 HZ. Setting i8253_clear_counter
 299          * to false tells pit_shutdown() not to zero the counter so that
 300          * the PIT really is shutdown. Generation 2 VMs don't have a PIT,
 301          * and setting this value has no effect.
 302          */
 303         i8253_clear_counter_on_shutdown = false;
 304
 305 #if IS_ENABLED(CONFIG_HYPERV)
 306         /*
 307          * Setup the hook to get control post apic initialization.
 308          */
 309         x86_platform.apic_post_init = hyperv_init;
 310         hyperv_setup_mmu_ops();
 311         /* Setup the IDT for hypervisor callback */
 312         alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
 313
 314         /* Setup the IDT for reenlightenment notifications */
 315         if (ms_hyperv.features & HV_X64_ACCESS_REENLIGHTENMENT)
 316                 alloc_intr_gate(HYPERV_REENLIGHTENMENT_VECTOR,
 317                                 hyperv_reenlightenment_vector);
 318
 319         /* Setup the IDT for stimer0 */
 320         if (ms_hyperv.misc_features & HV_STIMER_DIRECT_MODE_AVAILABLE)
 321                 alloc_intr_gate(HYPERV_STIMER0_VECTOR,
 322                                 hv_stimer0_callback_vector);
 323
 324 # ifdef CONFIG_SMP
 325         smp_ops.smp_prepare_boot_cpu = hv_smp_prepare_boot_cpu;
 326 # endif
 327
 328         /*
 329          * Hyper-V doesn't provide irq remapping for IO-APIC. To enable x2apic,
 330          * set x2apic destination mode to physcial mode when x2apic is available
 331          * and Hyper-V IOMMU driver makes sure cpus assigned with IO-APIC irqs
 332          * have 8-bit APIC id.
 333          */
 334 # ifdef CONFIG_X86_X2APIC
 335         if (x2apic_supported())
 336                 x2apic_phys = 1;
 337 # endif
 338
 339 #endif
 340 }
 341
 342 const __initconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
 343         .name                   = "Microsoft Hyper-V",
 344         .detect                 = ms_hyperv_platform,
 345         .type                   = X86_HYPER_MS_HYPERV,
 346         .init.init_platform     = ms_hyperv_init_platform,
 347 };