// SPDX-License-Identifier: GPL-2.0 /* * Core routines for interacting with Microsoft's Hyper-V hypervisor, * including hypervisor initialization. * * Copyright (C) 2021, Microsoft, Inc. * * Author : Michael Kelley <mikelley@microsoft.com> */ #include <linux/types.h>#include <linux/acpi.h>#include <linux/export.h>#include <linux/errno.h>#include <linux/version.h>#include <linux/cpuhotplug.h>#include <asm/mshyperv.h> static bool hyperv_initialized; int hv_get_hypervisor_version(union hv_hypervisor_version_info *info){	hv_get_vpreg_128(HV_REGISTER_HYPERVISOR_VERSION,			 (struct hv_get_vp_registers_output *)info); 	return 0;}EXPORT_SYMBOL_GPL(hv_get_hypervisor_version); #ifdef CONFIG_ACPI static bool __init hyperv_detect_via_acpi(void){	if (acpi_disabled)		return false;	/*	 * Hypervisor ID is only available in ACPI v6+, and the	 * structure layout was extended in v6 to accommodate that	 * new field.	 *	 * At the very minimum, this check makes sure not to read	 * past the FADT structure.	 *	 * It is also needed to catch running in some unknown	 * non-Hyper-V environment that has ACPI 5.x or less.	 * In such a case, it can't be Hyper-V.	 */	if (acpi_gbl_FADT.header.revision < 6)		return false;	return strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8) == 0;} #else static bool __init hyperv_detect_via_acpi(void){	return false;} #endif static bool __init hyperv_detect_via_smccc(void){	uuid_t hyperv_uuid = UUID_INIT(		0x58ba324d, 0x6447, 0x24cd,		0x75, 0x6c, 0xef, 0x8e,		0x24, 0x70, 0x59, 0x16); 	return arm_smccc_hypervisor_has_uuid(&hyperv_uuid);} static int __init hyperv_init(void){	struct hv_get_vp_registers_output	result;	u64	guest_id;	int	ret; 	/*	 * Allow for a kernel built with CONFIG_HYPERV to be running in	 * a non-Hyper-V environment.	 *	 * In such cases, do nothing and return success.	 */	if (!hyperv_detect_via_acpi() && !hyperv_detect_via_smccc())		return 0; 	/* Setup the guest ID */	guest_id = hv_generate_guest_id(LINUX_VERSION_CODE);	hv_set_vpreg(HV_REGISTER_GUEST_OS_ID, guest_id); 	/* Get the features and hints from Hyper-V */	hv_get_vpreg_128(HV_REGISTER_PRIVILEGES_AND_FEATURES_INFO, &result);	ms_hyperv.features = result.as32.a;	ms_hyperv.priv_high = result.as32.b;	ms_hyperv.misc_features = result.as32.c; 	hv_get_vpreg_128(HV_REGISTER_FEATURES_INFO, &result);	ms_hyperv.hints = result.as32.a; 	pr_info("Hyper-V: privilege flags low 0x%x, high 0x%x, hints 0x%x, misc 0x%x\n",		ms_hyperv.features, ms_hyperv.priv_high, ms_hyperv.hints,		ms_hyperv.misc_features); 	hv_identify_partition_type(); 	ret = hv_common_init();	if (ret)		return ret; 	ret = cpuhp_setup_state(CPUHP_AP_HYPERV_ONLINE, "arm64/hyperv_init:online",				hv_common_cpu_init, hv_common_cpu_die);	if (ret < 0) {		hv_common_free();		return ret;	} 	if (ms_hyperv.priv_high & HV_ACCESS_PARTITION_ID)		hv_get_partition_id();	ms_hyperv.vtl = get_vtl();	if (ms_hyperv.vtl > 0) /* non default VTL */		pr_info("Linux runs in Hyper-V Virtual Trust Level %d\n", ms_hyperv.vtl); 	ms_hyperv_late_init(); 	hyperv_initialized = true;	return 0;} early_initcall(hyperv_init); bool hv_is_hyperv_initialized(void){	return hyperv_initialized;}EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);