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/interrupt.h>
19 #include <asm/processor.h>
20 #include <asm/hypervisor.h>
21 #include <asm/hyperv.h>
22 #include <asm/mshyperv.h>
23 #include <asm/desc.h>
24 #include <asm/idle.h>
25 #include <asm/irq_regs.h>
26
27 struct ms_hyperv_info ms_hyperv;
28 EXPORT_SYMBOL_GPL(ms_hyperv);
29
30 static bool __init ms_hyperv_platform(void)
31 {
32 u32 eax;
33 u32 hyp_signature[3];
34
35 if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
36 return false;
37
38 cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
39 &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
40
41 return eax >= HYPERV_CPUID_MIN &&
42 eax <= HYPERV_CPUID_MAX &&
43 !memcmp("Microsoft Hv", hyp_signature, 12);
44 }
45
46 static cycle_t read_hv_clock(struct clocksource *arg)
47 {
48 cycle_t current_tick;
49 /*
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.
53 */
54 rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
55 return current_tick;
56 }
57
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),
63 .flags = CLOCK_SOURCE_IS_CONTINUOUS,
64 };
65
66 static void __init ms_hyperv_init_platform(void)
67 {
68 /*
69 * Extract the features and hints
70 */
71 ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
72 ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
73
74 printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n",
75 ms_hyperv.features, ms_hyperv.hints);
76
77 if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
78 clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
79 }
80
81 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
82 .name = "Microsoft HyperV",
83 .detect = ms_hyperv_platform,
84 .init_platform = ms_hyperv_init_platform,
85 };
86 EXPORT_SYMBOL(x86_hyper_ms_hyperv);
87
88 #if IS_ENABLED(CONFIG_HYPERV)
89 static int vmbus_irq = -1;
90 static irq_handler_t vmbus_isr;
91
92 void hv_register_vmbus_handler(int irq, irq_handler_t handler)
93 {
94 /*
95 * Setup the IDT for hypervisor callback.
96 */
97 alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
98
99 vmbus_irq = irq;
100 vmbus_isr = handler;
101 }
102
103 void hyperv_vector_handler(struct pt_regs *regs)
104 {
105 struct pt_regs *old_regs = set_irq_regs(regs);
106 struct irq_desc *desc;
107
108 irq_enter();
109 exit_idle();
110
111 desc = irq_to_desc(vmbus_irq);
112
113 if (desc)
114 generic_handle_irq_desc(vmbus_irq, desc);
115
116 irq_exit();
117 set_irq_regs(old_regs);
118 }
119 #else
120 void hv_register_vmbus_handler(int irq, irq_handler_t handler)
121 {
122 }
123 #endif
124 EXPORT_SYMBOL_GPL(hv_register_vmbus_handler);
125
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