Merge branch 'x86-hyperv-for-linus' of git://git.kernel.org/pub/scm/linux/kernel...
[~shefty/rdma-dev.git] / arch / x86 / kernel / cpu / mshyperv.c
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         /*
39          * Xen emulates Hyper-V to support enlightened Windows.
40          * Check to see first if we are on a Xen Hypervisor.
41          */
42         if (xen_cpuid_base())
43                 return false;
44
45         cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
46               &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
47
48         return eax >= HYPERV_CPUID_MIN &&
49                 eax <= HYPERV_CPUID_MAX &&
50                 !memcmp("Microsoft Hv", hyp_signature, 12);
51 }
52
53 static cycle_t read_hv_clock(struct clocksource *arg)
54 {
55         cycle_t current_tick;
56         /*
57          * Read the partition counter to get the current tick count. This count
58          * is set to 0 when the partition is created and is incremented in
59          * 100 nanosecond units.
60          */
61         rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
62         return current_tick;
63 }
64
65 static struct clocksource hyperv_cs = {
66         .name           = "hyperv_clocksource",
67         .rating         = 400, /* use this when running on Hyperv*/
68         .read           = read_hv_clock,
69         .mask           = CLOCKSOURCE_MASK(64),
70 };
71
72 static void __init ms_hyperv_init_platform(void)
73 {
74         /*
75          * Extract the features and hints
76          */
77         ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
78         ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
79
80         printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n",
81                ms_hyperv.features, ms_hyperv.hints);
82
83         if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
84                 clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
85 #if IS_ENABLED(CONFIG_HYPERV)
86         /*
87          * Setup the IDT for hypervisor callback.
88          */
89         alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR, hyperv_callback_vector);
90 #endif
91 }
92
93 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
94         .name                   = "Microsoft HyperV",
95         .detect                 = ms_hyperv_platform,
96         .init_platform          = ms_hyperv_init_platform,
97 };
98 EXPORT_SYMBOL(x86_hyper_ms_hyperv);
99
100 #if IS_ENABLED(CONFIG_HYPERV)
101 static int vmbus_irq = -1;
102 static irq_handler_t vmbus_isr;
103
104 void hv_register_vmbus_handler(int irq, irq_handler_t handler)
105 {
106         vmbus_irq = irq;
107         vmbus_isr = handler;
108 }
109
110 void hyperv_vector_handler(struct pt_regs *regs)
111 {
112         struct pt_regs *old_regs = set_irq_regs(regs);
113         struct irq_desc *desc;
114
115         irq_enter();
116         exit_idle();
117
118         desc = irq_to_desc(vmbus_irq);
119
120         if (desc)
121                 generic_handle_irq_desc(vmbus_irq, desc);
122
123         irq_exit();
124         set_irq_regs(old_regs);
125 }
126 #else
127 void hv_register_vmbus_handler(int irq, irq_handler_t handler)
128 {
129 }
130 #endif
131 EXPORT_SYMBOL_GPL(hv_register_vmbus_handler);