Merge branch 'x86-debug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[~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 <asm/processor.h>
18 #include <asm/hypervisor.h>
19 #include <asm/hyperv.h>
20 #include <asm/mshyperv.h>
21
22 struct ms_hyperv_info ms_hyperv;
23 EXPORT_SYMBOL_GPL(ms_hyperv);
24
25 static bool __init ms_hyperv_platform(void)
26 {
27         u32 eax;
28         u32 hyp_signature[3];
29
30         if (!boot_cpu_has(X86_FEATURE_HYPERVISOR))
31                 return false;
32
33         cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS,
34               &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]);
35
36         return eax >= HYPERV_CPUID_MIN &&
37                 eax <= HYPERV_CPUID_MAX &&
38                 !memcmp("Microsoft Hv", hyp_signature, 12);
39 }
40
41 static cycle_t read_hv_clock(struct clocksource *arg)
42 {
43         cycle_t current_tick;
44         /*
45          * Read the partition counter to get the current tick count. This count
46          * is set to 0 when the partition is created and is incremented in
47          * 100 nanosecond units.
48          */
49         rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
50         return current_tick;
51 }
52
53 static struct clocksource hyperv_cs = {
54         .name           = "hyperv_clocksource",
55         .rating         = 400, /* use this when running on Hyperv*/
56         .read           = read_hv_clock,
57         .mask           = CLOCKSOURCE_MASK(64),
58 };
59
60 static void __init ms_hyperv_init_platform(void)
61 {
62         /*
63          * Extract the features and hints
64          */
65         ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES);
66         ms_hyperv.hints    = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO);
67
68         printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n",
69                ms_hyperv.features, ms_hyperv.hints);
70
71         clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
72 }
73
74 const __refconst struct hypervisor_x86 x86_hyper_ms_hyperv = {
75         .name                   = "Microsoft HyperV",
76         .detect                 = ms_hyperv_platform,
77         .init_platform          = ms_hyperv_init_platform,
78 };
79 EXPORT_SYMBOL(x86_hyper_ms_hyperv);