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 <linux/kexec.h>
22 #include <asm/processor.h>
23 #include <asm/hypervisor.h>
24 #include <asm/hyperv.h>
25 #include <asm/mshyperv.h>
28 #include <asm/irq_regs.h>
29 #include <asm/i8259.h>
31 #include <asm/timer.h>
32 #include <asm/reboot.h>
34 struct ms_hyperv_info ms_hyperv
;
35 EXPORT_SYMBOL_GPL(ms_hyperv
);
37 static void (*hv_kexec_handler
)(void);
38 static void (*hv_crash_handler
)(struct pt_regs
*regs
);
40 #if IS_ENABLED(CONFIG_HYPERV)
41 static void (*vmbus_handler
)(void);
43 void hyperv_vector_handler(struct pt_regs
*regs
)
45 struct pt_regs
*old_regs
= set_irq_regs(regs
);
48 inc_irq_stat(irq_hv_callback_count
);
53 set_irq_regs(old_regs
);
56 void hv_setup_vmbus_irq(void (*handler
)(void))
58 vmbus_handler
= handler
;
60 * Setup the IDT for hypervisor callback. Prevent reallocation
63 if (!test_bit(HYPERVISOR_CALLBACK_VECTOR
, used_vectors
))
64 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR
,
65 hyperv_callback_vector
);
68 void hv_remove_vmbus_irq(void)
70 /* We have no way to deallocate the interrupt gate */
73 EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq
);
74 EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq
);
76 void hv_setup_kexec_handler(void (*handler
)(void))
78 hv_kexec_handler
= handler
;
80 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler
);
82 void hv_remove_kexec_handler(void)
84 hv_kexec_handler
= NULL
;
86 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler
);
88 void hv_setup_crash_handler(void (*handler
)(struct pt_regs
*regs
))
90 hv_crash_handler
= handler
;
92 EXPORT_SYMBOL_GPL(hv_setup_crash_handler
);
94 void hv_remove_crash_handler(void)
96 hv_crash_handler
= NULL
;
98 EXPORT_SYMBOL_GPL(hv_remove_crash_handler
);
101 static void hv_machine_shutdown(void)
103 if (kexec_in_progress
&& hv_kexec_handler
)
105 native_machine_shutdown();
108 static void hv_machine_crash_shutdown(struct pt_regs
*regs
)
110 if (hv_crash_handler
)
111 hv_crash_handler(regs
);
112 native_machine_crash_shutdown(regs
);
116 static uint32_t __init
ms_hyperv_platform(void)
119 u32 hyp_signature
[3];
121 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR
))
124 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS
,
125 &eax
, &hyp_signature
[0], &hyp_signature
[1], &hyp_signature
[2]);
127 if (eax
>= HYPERV_CPUID_MIN
&&
128 eax
<= HYPERV_CPUID_MAX
&&
129 !memcmp("Microsoft Hv", hyp_signature
, 12))
130 return HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS
;
135 static cycle_t
read_hv_clock(struct clocksource
*arg
)
137 cycle_t current_tick
;
139 * Read the partition counter to get the current tick count. This count
140 * is set to 0 when the partition is created and is incremented in
141 * 100 nanosecond units.
143 rdmsrl(HV_X64_MSR_TIME_REF_COUNT
, current_tick
);
147 static struct clocksource hyperv_cs
= {
148 .name
= "hyperv_clocksource",
149 .rating
= 400, /* use this when running on Hyperv*/
150 .read
= read_hv_clock
,
151 .mask
= CLOCKSOURCE_MASK(64),
152 .flags
= CLOCK_SOURCE_IS_CONTINUOUS
,
155 static void __init
ms_hyperv_init_platform(void)
158 * Extract the features and hints
160 ms_hyperv
.features
= cpuid_eax(HYPERV_CPUID_FEATURES
);
161 ms_hyperv
.misc_features
= cpuid_edx(HYPERV_CPUID_FEATURES
);
162 ms_hyperv
.hints
= cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO
);
164 printk(KERN_INFO
"HyperV: features 0x%x, hints 0x%x\n",
165 ms_hyperv
.features
, ms_hyperv
.hints
);
167 #ifdef CONFIG_X86_LOCAL_APIC
168 if (ms_hyperv
.features
& HV_X64_MSR_APIC_FREQUENCY_AVAILABLE
) {
170 * Get the APIC frequency.
172 u64 hv_lapic_frequency
;
174 rdmsrl(HV_X64_MSR_APIC_FREQUENCY
, hv_lapic_frequency
);
175 hv_lapic_frequency
= div_u64(hv_lapic_frequency
, HZ
);
176 lapic_timer_frequency
= hv_lapic_frequency
;
177 printk(KERN_INFO
"HyperV: LAPIC Timer Frequency: %#x\n",
178 lapic_timer_frequency
);
182 if (ms_hyperv
.features
& HV_X64_MSR_TIME_REF_COUNT_AVAILABLE
)
183 clocksource_register_hz(&hyperv_cs
, NSEC_PER_SEC
/100);
185 #ifdef CONFIG_X86_IO_APIC
189 machine_ops
.shutdown
= hv_machine_shutdown
;
190 machine_ops
.crash_shutdown
= hv_machine_crash_shutdown
;
191 mark_tsc_unstable("running on Hyper-V");
194 const __refconst
struct hypervisor_x86 x86_hyper_ms_hyperv
= {
195 .name
= "Microsoft HyperV",
196 .detect
= ms_hyperv_platform
,
197 .init_platform
= ms_hyperv_init_platform
,
199 EXPORT_SYMBOL(x86_hyper_ms_hyperv
);