2 * HyperV Detection code.
4 * Copyright (C) 2010, Novell, Inc.
5 * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
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.
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>
26 #include <asm/irq_regs.h>
27 #include <asm/i8259.h>
30 struct ms_hyperv_info ms_hyperv;
31 EXPORT_SYMBOL_GPL(ms_hyperv);
33 static uint32_t __init ms_hyperv_platform(void)
38 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
41 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
42 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
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;
52 static cycle_t read_hv_clock(struct clocksource *arg)
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.
60 rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
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),
71 static void __init ms_hyperv_init_platform(void)
74 * Extract the features and hints
76 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
77 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
79 printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n",
80 ms_hyperv.features, ms_hyperv.hints);
82 #ifdef CONFIG_X86_LOCAL_APIC
83 if (ms_hyperv.features & HV_X64_MSR_APIC_FREQUENCY_AVAILABLE) {
85 * Get the APIC frequency.
87 u64 hv_lapic_frequency;
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);
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.
99 if (efi_enabled(EFI_BOOT)) {
100 printk(KERN_INFO "HyperV: Using null_legacy_pic\n");
101 legacy_pic = &null_legacy_pic;
106 if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
107 clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
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,
115 EXPORT_SYMBOL(x86_hyper_ms_hyperv);
117 #if IS_ENABLED(CONFIG_HYPERV)
118 static int vmbus_irq = -1;
119 static irq_handler_t vmbus_isr;
121 void hv_register_vmbus_handler(int irq, irq_handler_t handler)
124 * Setup the IDT for hypervisor callback.
126 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
132 void hyperv_vector_handler(struct pt_regs *regs)
134 struct pt_regs *old_regs = set_irq_regs(regs);
135 struct irq_desc *desc;
140 desc = irq_to_desc(vmbus_irq);
143 generic_handle_irq_desc(vmbus_irq, desc);
146 set_irq_regs(old_regs);
149 void hv_register_vmbus_handler(int irq, irq_handler_t handler)
153 EXPORT_SYMBOL_GPL(hv_register_vmbus_handler);