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/module.h>
  17 #include <linux/hardirq.h>
  18 #include <linux/efi.h>
  19 #include <linux/interrupt.h>
  20 #include <asm/processor.h>
  21 #include <asm/hypervisor.h>
  22 #include <asm/hyperv.h>
  23 #include <asm/mshyperv.h>
  24 #include <asm/desc.h>
  25 #include <asm/idle.h>
  26 #include <asm/irq_regs.h>
  27 #include <asm/i8259.h>
  28 #include <asm/apic.h>
  29 #include <asm/timer.h>
  30
  31 struct ms_hyperv_info ms_hyperv;
  32 EXPORT_SYMBOL_GPL(ms_hyperv);
  33
  34 static uint32_t  __init ms_hyperv_platform(void)
  35 {
  36         u32 eax;
  37         u32 hyp_signature[3];
  38
  39         if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
  40                 return 0;
  41
  42         cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
  43               &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
  44
  45         if (eax >= HYPERV_CPUID_MIN &&
  46             eax <= HYPERV_CPUID_MAX &&
  47             !memcmp("Microsoft Hv", hyp_signature, 12))
  48                 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS;
  49
  50         return 0;
  51 }
  52
  53 static cycle_t read_hv_clock(struct clocksource *arg)
  54 {
  55         cycle_t current_tick;
  56         /*
  57          * Read the partition counter to get the current tick count. This count
  58          * is set to 0 when the partition is created and is incremented in
  59          * 100 nanosecond units.
  60          */
  61         rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
  62         return current_tick;
  63 }
  64
  65 static struct clocksource hyperv_cs = {
  66         .name           = "hyperv_clocksource",
  67         .rating         = 400, /* use this when running on Hyperv*/
  68         .read           = read_hv_clock,
  69         .mask           = CLOCKSOURCE_MASK(64),
  70 };
  71
  72 static void __init ms_hyperv_init_platform(void)
  73 {
  74         /*
  75          * Extract the features and hints
  76          */
  77         ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
  78         ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
  79
  80         printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n",
  81                ms_hyperv.features, ms_hyperv.hints);
  82
  83 #ifdef CONFIG_X86_LOCAL_APIC
  84         if (ms_hyperv.features & HV_X64_MSR_APIC_FREQUENCY_AVAILABLE) {
  85                 /*
  86                  * Get the APIC frequency.
  87                  */
  88                 u64     hv_lapic_frequency;
  89
  90                 rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency);
  91                 hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ);
  92                 lapic_timer_frequency = hv_lapic_frequency;
  93                 printk(KERN_INFO "HyperV: LAPIC Timer Frequency: %#x\n",
  94                                 lapic_timer_frequency);
  95
  96                 /*
  97                  * On Hyper-V, when we are booting off an EFI firmware stack,
  98                  * we do not have many legacy devices including PIC, PIT etc.
  99                  */
 100                 if (efi_enabled(EFI_BOOT)) {
 101                         printk(KERN_INFO "HyperV: Using null_legacy_pic\n");
 102                         legacy_pic = &null_legacy_pic;
 103                 }
 104         }
 105 #endif
 106
 107         if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
 108                 clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
 109
 110 #ifdef CONFIG_X86_IO_APIC
 111         no_timer_check = 1;
 112 #endif
 113
 114 }
 115
 116 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
 117         .name                   = "Microsoft HyperV",
 118         .detect                 = ms_hyperv_platform,
 119         .init_platform          = ms_hyperv_init_platform,
 120 };
 121 EXPORT_SYMBOL(x86_hyper_ms_hyperv);
 122
 123 #if IS_ENABLED(CONFIG_HYPERV)
 124 static int vmbus_irq = -1;
 125 static irq_handler_t vmbus_isr;
 126
 127 void hv_register_vmbus_handler(int irq, irq_handler_t handler)
 128 {
 129         /*
 130          * Setup the IDT for hypervisor callback.
 131          */
 132         alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
 133
 134         vmbus_irq = irq;
 135         vmbus_isr = handler;
 136 }
 137
 138 void hyperv_vector_handler(struct pt_regs *regs)
 139 {
 140         struct pt_regs *old_regs = set_irq_regs(regs);
 141         struct irq_desc *desc;
 142
 143         irq_enter();
 144         exit_idle();
 145
 146         desc = irq_to_desc(vmbus_irq);
 147
 148         if (desc)
 149                 generic_handle_irq_desc(vmbus_irq, desc);
 150
 151         irq_exit();
 152         set_irq_regs(old_regs);
 153 }
 154 #else
 155 void hv_register_vmbus_handler(int irq, irq_handler_t handler)
 156 {
 157 }
 158 #endif
 159 EXPORT_SYMBOL_GPL(hv_register_vmbus_handler);