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a2a47c6c KS |
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 | |
9fa02317 | 9 | * the Free Software Foundation; version 2 of the License. |
a2a47c6c KS |
10 | * |
11 | */ | |
12 | ||
13 | #include <linux/types.h> | |
6f4151c8 S |
14 | #include <linux/time.h> |
15 | #include <linux/clocksource.h> | |
3998d095 | 16 | #include <linux/module.h> |
a2a47c6c | 17 | #include <asm/processor.h> |
e08cae41 | 18 | #include <asm/hypervisor.h> |
a2a47c6c KS |
19 | #include <asm/hyperv.h> |
20 | #include <asm/mshyperv.h> | |
21 | ||
e08cae41 | 22 | struct ms_hyperv_info ms_hyperv; |
9279aa55 | 23 | EXPORT_SYMBOL_GPL(ms_hyperv); |
a2a47c6c | 24 | |
e08cae41 | 25 | static bool __init ms_hyperv_platform(void) |
a2a47c6c | 26 | { |
e08cae41 PA |
27 | u32 eax; |
28 | u32 hyp_signature[3]; | |
a2a47c6c | 29 | |
e08cae41 PA |
30 | if (!boot_cpu_has(X86_FEATURE_HYPERVISOR)) |
31 | return false; | |
a2a47c6c | 32 | |
e08cae41 PA |
33 | cpuid(HYPERV_CPUID_VENDOR_AND_MAX_FUNCTIONS, |
34 | &eax, &hyp_signature[0], &hyp_signature[1], &hyp_signature[2]); | |
a2a47c6c | 35 | |
e08cae41 PA |
36 | return eax >= HYPERV_CPUID_MIN && |
37 | eax <= HYPERV_CPUID_MAX && | |
38 | !memcmp("Microsoft Hv", hyp_signature, 12); | |
a2a47c6c KS |
39 | } |
40 | ||
6f4151c8 S |
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 | ||
e08cae41 | 60 | static void __init ms_hyperv_init_platform(void) |
a2a47c6c | 61 | { |
a2a47c6c | 62 | /* |
e08cae41 | 63 | * Extract the features and hints |
a2a47c6c | 64 | */ |
e08cae41 PA |
65 | ms_hyperv.features = cpuid_eax(HYPERV_CPUID_FEATURES); |
66 | ms_hyperv.hints = cpuid_eax(HYPERV_CPUID_ENLIGHTMENT_INFO); | |
a2a47c6c | 67 | |
e08cae41 PA |
68 | printk(KERN_INFO "HyperV: features 0x%x, hints 0x%x\n", |
69 | ms_hyperv.features, ms_hyperv.hints); | |
6f4151c8 S |
70 | |
71 | clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100); | |
a2a47c6c | 72 | } |
e08cae41 PA |
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 | }; | |
96f6e775 | 79 | EXPORT_SYMBOL(x86_hyper_ms_hyperv); |