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 <linux/irq.h>
21 #include <asm/processor.h>
22 #include <asm/hypervisor.h>
23 #include <asm/hyperv.h>
24 #include <asm/mshyperv.h>
27 #include <asm/irq_regs.h>
28 #include <asm/i8259.h>
30 #include <asm/timer.h>
32 struct ms_hyperv_info ms_hyperv
;
33 EXPORT_SYMBOL_GPL(ms_hyperv
);
35 #if IS_ENABLED(CONFIG_HYPERV)
36 static void (*vmbus_handler
)(void);
38 void hyperv_vector_handler(struct pt_regs
*regs
)
40 struct pt_regs
*old_regs
= set_irq_regs(regs
);
43 inc_irq_stat(irq_hv_callback_count
);
48 set_irq_regs(old_regs
);
51 void hv_setup_vmbus_irq(void (*handler
)(void))
53 vmbus_handler
= handler
;
55 * Setup the IDT for hypervisor callback. Prevent reallocation
58 if (!test_bit(HYPERVISOR_CALLBACK_VECTOR
, used_vectors
))
59 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR
,
60 hyperv_callback_vector
);
63 void hv_remove_vmbus_irq(void)
65 /* We have no way to deallocate the interrupt gate */
68 EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq
);
69 EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq
);
72 static uint32_t __init
ms_hyperv_platform(void)
77 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR
))
80 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS
,
81 &eax
, &hyp_signature
[0], &hyp_signature
[1], &hyp_signature
[2]);
83 if (eax
>= HYPERV_CPUID_MIN
&&
84 eax
<= HYPERV_CPUID_MAX
&&
85 !memcmp("Microsoft Hv", hyp_signature
, 12))
86 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS
;
91 static cycle_t
read_hv_clock(struct clocksource
*arg
)
95 * Read the partition counter to get the current tick count. This count
96 * is set to 0 when the partition is created and is incremented in
97 * 100 nanosecond units.
99 rdmsrl(HV_X64_MSR_TIME_REF_COUNT
, current_tick
);
103 static struct clocksource hyperv_cs
= {
104 .name
= "hyperv_clocksource",
105 .rating
= 400, /* use this when running on Hyperv*/
106 .read
= read_hv_clock
,
107 .mask
= CLOCKSOURCE_MASK(64),
108 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
111 static void __init
ms_hyperv_init_platform(void)
114 * Extract the features and hints
116 ms_hyperv
.features
= cpuid_eax(HYPERV_CPUID_FEATURES
);
117 ms_hyperv
.hints
= cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO
);
119 printk(KERN_INFO
"HyperV: features 0x%x, hints 0x%x\n",
120 ms_hyperv
.features
, ms_hyperv
.hints
);
122 #ifdef CONFIG_X86_LOCAL_APIC
123 if (ms_hyperv
.features
& HV_X64_MSR_APIC_FREQUENCY_AVAILABLE
) {
125 * Get the APIC frequency.
127 u64 hv_lapic_frequency
;
129 rdmsrl(HV_X64_MSR_APIC_FREQUENCY
, hv_lapic_frequency
);
130 hv_lapic_frequency
= div_u64(hv_lapic_frequency
, HZ
);
131 lapic_timer_frequency
= hv_lapic_frequency
;
132 printk(KERN_INFO
"HyperV: LAPIC Timer Frequency: %#x\n",
133 lapic_timer_frequency
);
137 if (ms_hyperv
.features
& HV_X64_MSR_TIME_REF_COUNT_AVAILABLE
)
138 clocksource_register_hz(&hyperv_cs
, NSEC_PER_SEC
/100);
140 #ifdef CONFIG_X86_IO_APIC
146 const __refconst
struct hypervisor_x86 x86_hyper_ms_hyperv
= {
147 .name
= "Microsoft HyperV",
148 .detect
= ms_hyperv_platform
,
149 .init_platform
= ms_hyperv_init_platform
,
151 EXPORT_SYMBOL(x86_hyper_ms_hyperv
);