1 // SPDX-License-Identifier: GPL-2.0
4 * Core routines for interacting with Microsoft's Hyper-V hypervisor,
5 * including hypervisor initialization.
7 * Copyright (C) 2021, Microsoft, Inc.
9 * Author : Michael Kelley <mikelley@microsoft.com>
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>
20 static bool hyperv_initialized
;
22 static int __init
hyperv_init(void)
24 struct hv_get_vp_registers_output result
;
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.
37 if (strncmp((char *)&acpi_gbl_FADT
.hypervisor_id
, "MsHyperV", 8))
40 /* Setup the guest ID */
41 guest_id
= generate_guest_id(0, LINUX_VERSION_CODE
, 0);
42 hv_set_vpreg(HV_REGISTER_GUEST_OSID
, guest_id
);
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
;
50 hv_get_vpreg_128(HV_REGISTER_ENLIGHTENMENTS
, &result
);
51 ms_hyperv
.hints
= result
.as32
.a
;
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
);
57 /* Get information about the Hyper-V host version */
58 hv_get_vpreg_128(HV_REGISTER_HYPERVISOR_VERSION
, &result
);
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);
66 ret
= hv_common_init();
70 ret
= cpuhp_setup_state(CPUHP_AP_ONLINE_DYN
, "arm64/hyperv_init:online",
71 hv_common_cpu_init
, hv_common_cpu_die
);
77 hyperv_initialized
= true;
81 early_initcall(hyperv_init
);
83 bool hv_is_hyperv_initialized(void)
85 return hyperv_initialized
;
87 EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized
);