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 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 83 bool hv_is_hyperv_initialized(void) 84 { 85 return hyperv_initialized; 86 } 87 EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized); 88