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1 /*
2  * HyperV  Detection code.
3  *
4  * Copyright (C) 2010, Novell, Inc.
5  * Author : K. Y. Srinivasan <ksrinivasan@novell.com>
6  *
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.
10  *
11  */
12
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>
26 #include <asm/desc.h>
27 #include <asm/idle.h>
28 #include <asm/irq_regs.h>
29 #include <asm/i8259.h>
30 #include <asm/apic.h>
31 #include <asm/timer.h>
32 #include <asm/reboot.h>
33
34 struct ms_hyperv_info ms_hyperv;
35 EXPORT_SYMBOL_GPL(ms_hyperv);
36
37 #if IS_ENABLED(CONFIG_HYPERV)
38 static void (*vmbus_handler)(void);
39 static void (*hv_kexec_handler)(void);
40 static void (*hv_crash_handler)(struct pt_regs *regs);
41
42 void hyperv_vector_handler(struct pt_regs *regs)
43 {
44         struct pt_regs *old_regs = set_irq_regs(regs);
45
46         entering_irq();
47         inc_irq_stat(irq_hv_callback_count);
48         if (vmbus_handler)
49                 vmbus_handler();
50
51         exiting_irq();
52         set_irq_regs(old_regs);
53 }
54
55 void hv_setup_vmbus_irq(void (*handler)(void))
56 {
57         vmbus_handler = handler;
58         /*
59          * Setup the IDT for hypervisor callback. Prevent reallocation
60          * at module reload.
61          */
62         if (!test_bit(HYPERVISOR_CALLBACK_VECTOR, used_vectors))
63                 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR,
64                                 hyperv_callback_vector);
65 }
66
67 void hv_remove_vmbus_irq(void)
68 {
69         /* We have no way to deallocate the interrupt gate */
70         vmbus_handler = NULL;
71 }
72 EXPORT_SYMBOL_GPL(hv_setup_vmbus_irq);
73 EXPORT_SYMBOL_GPL(hv_remove_vmbus_irq);
74
75 void hv_setup_kexec_handler(void (*handler)(void))
76 {
77         hv_kexec_handler = handler;
78 }
79 EXPORT_SYMBOL_GPL(hv_setup_kexec_handler);
80
81 void hv_remove_kexec_handler(void)
82 {
83         hv_kexec_handler = NULL;
84 }
85 EXPORT_SYMBOL_GPL(hv_remove_kexec_handler);
86
87 void hv_setup_crash_handler(void (*handler)(struct pt_regs *regs))
88 {
89         hv_crash_handler = handler;
90 }
91 EXPORT_SYMBOL_GPL(hv_setup_crash_handler);
92
93 void hv_remove_crash_handler(void)
94 {
95         hv_crash_handler = NULL;
96 }
97 EXPORT_SYMBOL_GPL(hv_remove_crash_handler);
98
99 #ifdef CONFIG_KEXEC_CORE
100 static void hv_machine_shutdown(void)
101 {
102         if (kexec_in_progress && hv_kexec_handler)
103                 hv_kexec_handler();
104         native_machine_shutdown();
105 }
106
107 static void hv_machine_crash_shutdown(struct pt_regs *regs)
108 {
109         if (hv_crash_handler)
110                 hv_crash_handler(regs);
111         native_machine_crash_shutdown(regs);
112 }
113 #endif /* CONFIG_KEXEC_CORE */
114 #endif /* CONFIG_HYPERV */
115
116 static uint32_t  __init ms_hyperv_platform(void)
117 {
118         u32 eax;
119         u32 hyp_signature[3];
120
121         if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
122                 return 0;
123
124         cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
125               &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
126
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;
131
132         return 0;
133 }
134
135 static cycle_t read_hv_clock(struct clocksource *arg)
136 {
137         cycle_t current_tick;
138         /*
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.
142          */
143         rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
144         return current_tick;
145 }
146
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,
153 };
154
155 static void __init ms_hyperv_init_platform(void)
156 {
157         /*
158          * Extract the features and hints
159          */
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);
163
164         printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n",
165                ms_hyperv.features, ms_hyperv.hints);
166
167 #ifdef CONFIG_X86_LOCAL_APIC
168         if (ms_hyperv.features & HV_X64_MSR_APIC_FREQUENCY_AVAILABLE) {
169                 /*
170                  * Get the APIC frequency.
171                  */
172                 u64     hv_lapic_frequency;
173
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);
179         }
180 #endif
181
182         if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
183                 clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
184
185 #ifdef CONFIG_X86_IO_APIC
186         no_timer_check = 1;
187 #endif
188
189 #if IS_ENABLED(CONFIG_HYPERV) && defined(CONFIG_KEXEC_CORE)
190         machine_ops.shutdown = hv_machine_shutdown;
191         machine_ops.crash_shutdown = hv_machine_crash_shutdown;
192 #endif
193         mark_tsc_unstable("running on Hyper-V");
194 }
195
196 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
197         .name                   = "Microsoft HyperV",
198         .detect                 = ms_hyperv_platform,
199         .init_platform          = ms_hyperv_init_platform,
200 };
201 EXPORT_SYMBOL(x86_hyper_ms_hyperv);