summaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/cpu/mshyperv.c
blob: 0a490ca278e7be1fa57a68734748e4d696a62aa2 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
/*
 * HyperV  Detection code.
 *
 * Copyright (C) 2010, Novell, Inc.
 * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 */

#include <linux/types.h>
#include <linux/time.h>
#include <linux/clocksource.h>
#include <linux/module.h>
#include <linux/hardirq.h>
#include <linux/efi.h>
#include <linux/interrupt.h>
#include <asm/processor.h>
#include <asm/hypervisor.h>
#include <asm/hyperv.h>
#include <asm/mshyperv.h>
#include <asm/desc.h>
#include <asm/idle.h>
#include <asm/irq_regs.h>
#include <asm/i8259.h>

struct ms_hyperv_info ms_hyperv;
EXPORT_SYMBOL_GPL(ms_hyperv);

static uint32_t  __init ms_hyperv_platform(void)
{
	u32 eax;
	u32 hyp_signature[3];

	if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
		return 0;

	cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
	      &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);

	if (eax >= HYPERV_CPUID_MIN &&
	    eax <= HYPERV_CPUID_MAX &&
	    !memcmp("Microsoft Hv", hyp_signature, 12))
		return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS;

	return 0;
}

static cycle_t read_hv_clock(struct clocksource *arg)
{
	cycle_t current_tick;
	/*
	 * Read the partition counter to get the current tick count. This count
	 * is set to 0 when the partition is created and is incremented in
	 * 100 nanosecond units.
	 */
	rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
	return current_tick;
}

static struct clocksource hyperv_cs = {
	.name		= "hyperv_clocksource",
	.rating		= 400, /* use this when running on Hyperv*/
	.read		= read_hv_clock,
	.mask		= CLOCKSOURCE_MASK(64),
};

static void __init ms_hyperv_init_platform(void)
{
	u64	hv_lapic_frequency;

	/*
	 * Extract the features and hints
	 */
	ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
	ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);

	printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n",
	       ms_hyperv.features, ms_hyperv.hints);

	if (ms_hyperv.features & HV_X64_MSR_APIC_FREQUENCY_AVAILABLE) {
		/*
		 * Get the APIC frequency.
		 */
		rdmsrl(HV_X64_MSR_APIC_FREQUENCY, hv_lapic_frequency);
		hv_lapic_frequency = div_u64(hv_lapic_frequency, HZ);
		lapic_timer_frequency = hv_lapic_frequency;
		printk(KERN_INFO "HyperV: LAPIC Timer Frequency: %#x\n",
				lapic_timer_frequency);

		/*
		 * On Hyper-V, when we are booting off an EFI firmware stack,
		 * we do not have many legacy devices including PIC, PIT etc.
		 */
		if (efi_enabled(EFI_BOOT)) {
			printk(KERN_INFO "HyperV: Using null_legacy_pic\n");
			legacy_pic = &null_legacy_pic;
		}
	}

	if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
		clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
}

const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
	.name			= "Microsoft HyperV",
	.detect			= ms_hyperv_platform,
	.init_platform		= ms_hyperv_init_platform,
};
EXPORT_SYMBOL(x86_hyper_ms_hyperv);

#if IS_ENABLED(CONFIG_HYPERV)
static int vmbus_irq = -1;
static irq_handler_t vmbus_isr;

void hv_register_vmbus_handler(int irq, irq_handler_t handler)
{
	/*
	 * Setup the IDT for hypervisor callback.
	 */
	alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);

	vmbus_irq = irq;
	vmbus_isr = handler;
}

void hyperv_vector_handler(struct pt_regs *regs)
{
	struct pt_regs *old_regs = set_irq_regs(regs);
	struct irq_desc *desc;

	irq_enter();
	exit_idle();

	desc = irq_to_desc(vmbus_irq);

	if (desc)
		generic_handle_irq_desc(vmbus_irq, desc);

	irq_exit();
	set_irq_regs(old_regs);
}
#else
void hv_register_vmbus_handler(int irq, irq_handler_t handler)
{
}
#endif
EXPORT_SYMBOL_GPL(hv_register_vmbus_handler);
OpenPOWER on IntegriCloud