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/interrupt.h>
19 #include <asm/processor.h>
20 #include <asm/hypervisor.h>
21 #include <asm/hyperv.h>
22 #include <asm/mshyperv.h>
25 #include <asm/irq_regs.h>
27 struct ms_hyperv_info ms_hyperv;
28 EXPORT_SYMBOL_GPL(ms_hyperv);
30 static bool __init ms_hyperv_platform(void)
35 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
38 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
39 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
41 return eax >= HYPERV_CPUID_MIN &&
42 eax <= HYPERV_CPUID_MAX &&
43 !memcmp("Microsoft Hv", hyp_signature, 12);
46 static cycle_t read_hv_clock(struct clocksource *arg)
50 * Read the partition counter to get the current tick count. This count
51 * is set to 0 when the partition is created and is incremented in
52 * 100 nanosecond units.
54 rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
58 static struct clocksource hyperv_cs = {
59 .name = "hyperv_clocksource",
60 .rating = 400, /* use this when running on Hyperv*/
61 .read = read_hv_clock,
62 .mask = CLOCKSOURCE_MASK(64),
65 static void __init ms_hyperv_init_platform(void)
68 * Extract the features and hints
70 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
71 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
73 printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n",
74 ms_hyperv.features, ms_hyperv.hints);
76 if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
77 clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
80 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
81 .name = "Microsoft HyperV",
82 .detect = ms_hyperv_platform,
83 .init_platform = ms_hyperv_init_platform,
85 EXPORT_SYMBOL(x86_hyper_ms_hyperv);
87 #if IS_ENABLED(CONFIG_HYPERV)
88 static int vmbus_irq = -1;
89 static irq_handler_t vmbus_isr;
91 void hv_register_vmbus_handler(int irq, irq_handler_t handler)
94 * Setup the IDT for hypervisor callback.
96 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
102 void hyperv_vector_handler(struct pt_regs *regs)
104 struct pt_regs *old_regs = set_irq_regs(regs);
105 struct irq_desc *desc;
110 desc = irq_to_desc(vmbus_irq);
113 generic_handle_irq_desc(vmbus_irq, desc);
116 set_irq_regs(old_regs);
119 void hv_register_vmbus_handler(int irq, irq_handler_t handler)
123 EXPORT_SYMBOL_GPL(hv_register_vmbus_handler);