1 // SPDX-License-Identifier: GPL-2.0
2
3 /*
4 * Core routines for interacting with Microsoft's Hyper-V hypervisor,
5 * including hypervisor initialization.
6 *
7 * Copyright (C) 2021, Microsoft, Inc.
8 *
9 * Author : Michael Kelley <mikelley@microsoft.com>
10 */
11
12 #include <linux/types.h>
13 #include <linux/acpi.h>
14 #include <linux/export.h>
15 #include <linux/errno.h>
16 #include <linux/version.h>
17 #include <linux/cpuhotplug.h>
18 #include <asm/mshyperv.h>
19
20 static bool hyperv_initialized;
21
hv_get_hypervisor_version(union hv_hypervisor_version_info * info)22 int hv_get_hypervisor_version(union hv_hypervisor_version_info *info)
23 {
24 hv_get_vpreg_128(HV_REGISTER_HYPERVISOR_VERSION,
25 (struct hv_get_vp_registers_output *)info);
26
27 return 0;
28 }
29 EXPORT_SYMBOL_GPL(hv_get_hypervisor_version);
30
hyperv_init(void)31 static int __init hyperv_init(void)
32 {
33 struct hv_get_vp_registers_output result;
34 u64 guest_id;
35 int ret;
36
37 /*
38 * Allow for a kernel built with CONFIG_HYPERV to be running in
39 * a non-Hyper-V environment, including on DT instead of ACPI.
40 * In such cases, do nothing and return success.
41 */
42 if (acpi_disabled)
43 return 0;
44
45 if (strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8))
46 return 0;
47
48 /* Setup the guest ID */
49 guest_id = hv_generate_guest_id(LINUX_VERSION_CODE);
50 hv_set_vpreg(HV_REGISTER_GUEST_OS_ID, guest_id);
51
52 /* Get the features and hints from Hyper-V */
53 hv_get_vpreg_128(HV_REGISTER_PRIVILEGES_AND_FEATURES_INFO, &result);
54 ms_hyperv.features = result.as32.a;
55 ms_hyperv.priv_high = result.as32.b;
56 ms_hyperv.misc_features = result.as32.c;
57
58 hv_get_vpreg_128(HV_REGISTER_FEATURES_INFO, &result);
59 ms_hyperv.hints = result.as32.a;
60
61 pr_info("Hyper-V: privilege flags low 0x%x, high 0x%x, hints 0x%x, misc 0x%x\n",
62 ms_hyperv.features, ms_hyperv.priv_high, ms_hyperv.hints,
63 ms_hyperv.misc_features);
64
65 hv_identify_partition_type();
66
67 ret = hv_common_init();
68 if (ret)
69 return ret;
70
71 ret = cpuhp_setup_state(CPUHP_AP_HYPERV_ONLINE, "arm64/hyperv_init:online",
72 hv_common_cpu_init, hv_common_cpu_die);
73 if (ret < 0) {
74 hv_common_free();
75 return ret;
76 }
77
78 if (ms_hyperv.priv_high & HV_ACCESS_PARTITION_ID)
79 hv_get_partition_id();
80
81 ms_hyperv_late_init();
82
83 hyperv_initialized = true;
84 return 0;
85 }
86
87 early_initcall(hyperv_init);
88
hv_is_hyperv_initialized(void)89 bool hv_is_hyperv_initialized(void)
90 {
91 return hyperv_initialized;
92 }
93 EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);
94