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