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
hyperv_init(void)22 static int __init hyperv_init(void)
23 {
24 struct hv_get_vp_registers_output result;
25 u32 a, b, c, d;
26 u64 guest_id;
27 int ret;
28
29 /*
30 * Allow for a kernel built with CONFIG_HYPERV to be running in
31 * a non-Hyper-V environment, including on DT instead of ACPI.
32 * In such cases, do nothing and return success.
33 */
34 if (acpi_disabled)
35 return 0;
36
37 if (strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8))
38 return 0;
39
40 /* Setup the guest ID */
41 guest_id = hv_generate_guest_id(LINUX_VERSION_CODE);
42 hv_set_vpreg(HV_REGISTER_GUEST_OSID, guest_id);
43
44 /* Get the features and hints from Hyper-V */
45 hv_get_vpreg_128(HV_REGISTER_FEATURES, &result);
46 ms_hyperv.features = result.as32.a;
47 ms_hyperv.priv_high = result.as32.b;
48 ms_hyperv.misc_features = result.as32.c;
49
50 hv_get_vpreg_128(HV_REGISTER_ENLIGHTENMENTS, &result);
51 ms_hyperv.hints = result.as32.a;
52
53 pr_info("Hyper-V: privilege flags low 0x%x, high 0x%x, hints 0x%x, misc 0x%x\n",
54 ms_hyperv.features, ms_hyperv.priv_high, ms_hyperv.hints,
55 ms_hyperv.misc_features);
56
57 /* Get information about the Hyper-V host version */
58 hv_get_vpreg_128(HV_REGISTER_HYPERVISOR_VERSION, &result);
59 a = result.as32.a;
60 b = result.as32.b;
61 c = result.as32.c;
62 d = result.as32.d;
63 pr_info("Hyper-V: Host Build %d.%d.%d.%d-%d-%d\n",
64 b >> 16, b & 0xFFFF, a, d & 0xFFFFFF, c, d >> 24);
65
66 ret = hv_common_init();
67 if (ret)
68 return ret;
69
70 ret = cpuhp_setup_state(CPUHP_AP_HYPERV_ONLINE, "arm64/hyperv_init:online",
71 hv_common_cpu_init, hv_common_cpu_die);
72 if (ret < 0) {
73 hv_common_free();
74 return ret;
75 }
76
77 hyperv_initialized = true;
78 return 0;
79 }
80
81 early_initcall(hyperv_init);
82
hv_is_hyperv_initialized(void)83 bool hv_is_hyperv_initialized(void)
84 {
85 return hyperv_initialized;
86 }
87 EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);
88