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