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e956ee9491
The hyperv guest code might run in various Virtual Trust Levels. Report the level when the kernel boots in the non-default (0) one. Signed-off-by: Roman Kisel <romank@linux.microsoft.com> Reviewed-by: Michael Kelley <mhklinux@outlook.com> Link: https://lore.kernel.org/r/20250428210742.435282-7-romank@linux.microsoft.com Signed-off-by: Wei Liu <wei.liu@kernel.org> Message-ID: <20250428210742.435282-7-romank@linux.microsoft.com>
136 lines
3.2 KiB
C
136 lines
3.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Core routines for interacting with Microsoft's Hyper-V hypervisor,
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* including hypervisor initialization.
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*
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* Copyright (C) 2021, Microsoft, Inc.
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*
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* Author : Michael Kelley <mikelley@microsoft.com>
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*/
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#include <linux/types.h>
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#include <linux/acpi.h>
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#include <linux/export.h>
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#include <linux/errno.h>
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#include <linux/version.h>
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#include <linux/cpuhotplug.h>
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#include <asm/mshyperv.h>
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static bool hyperv_initialized;
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int hv_get_hypervisor_version(union hv_hypervisor_version_info *info)
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{
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hv_get_vpreg_128(HV_REGISTER_HYPERVISOR_VERSION,
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(struct hv_get_vp_registers_output *)info);
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return 0;
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}
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EXPORT_SYMBOL_GPL(hv_get_hypervisor_version);
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#ifdef CONFIG_ACPI
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static bool __init hyperv_detect_via_acpi(void)
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{
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if (acpi_disabled)
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return false;
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/*
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* Hypervisor ID is only available in ACPI v6+, and the
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* structure layout was extended in v6 to accommodate that
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* new field.
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*
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* At the very minimum, this check makes sure not to read
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* past the FADT structure.
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*
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* It is also needed to catch running in some unknown
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* non-Hyper-V environment that has ACPI 5.x or less.
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* In such a case, it can't be Hyper-V.
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*/
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if (acpi_gbl_FADT.header.revision < 6)
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return false;
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return strncmp((char *)&acpi_gbl_FADT.hypervisor_id, "MsHyperV", 8) == 0;
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}
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#else
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static bool __init hyperv_detect_via_acpi(void)
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{
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return false;
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}
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#endif
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static bool __init hyperv_detect_via_smccc(void)
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{
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uuid_t hyperv_uuid = UUID_INIT(
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0x58ba324d, 0x6447, 0x24cd,
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0x75, 0x6c, 0xef, 0x8e,
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0x24, 0x70, 0x59, 0x16);
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return arm_smccc_hypervisor_has_uuid(&hyperv_uuid);
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}
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static int __init hyperv_init(void)
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{
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struct hv_get_vp_registers_output result;
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u64 guest_id;
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int ret;
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/*
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* Allow for a kernel built with CONFIG_HYPERV to be running in
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* a non-Hyper-V environment.
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*
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* In such cases, do nothing and return success.
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*/
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if (!hyperv_detect_via_acpi() && !hyperv_detect_via_smccc())
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return 0;
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/* Setup the guest ID */
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guest_id = hv_generate_guest_id(LINUX_VERSION_CODE);
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hv_set_vpreg(HV_REGISTER_GUEST_OS_ID, guest_id);
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/* Get the features and hints from Hyper-V */
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hv_get_vpreg_128(HV_REGISTER_PRIVILEGES_AND_FEATURES_INFO, &result);
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ms_hyperv.features = result.as32.a;
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ms_hyperv.priv_high = result.as32.b;
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ms_hyperv.misc_features = result.as32.c;
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hv_get_vpreg_128(HV_REGISTER_FEATURES_INFO, &result);
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ms_hyperv.hints = result.as32.a;
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pr_info("Hyper-V: privilege flags low 0x%x, high 0x%x, hints 0x%x, misc 0x%x\n",
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ms_hyperv.features, ms_hyperv.priv_high, ms_hyperv.hints,
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ms_hyperv.misc_features);
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hv_identify_partition_type();
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ret = hv_common_init();
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if (ret)
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return ret;
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ret = cpuhp_setup_state(CPUHP_AP_HYPERV_ONLINE, "arm64/hyperv_init:online",
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hv_common_cpu_init, hv_common_cpu_die);
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if (ret < 0) {
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hv_common_free();
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return ret;
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}
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if (ms_hyperv.priv_high & HV_ACCESS_PARTITION_ID)
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hv_get_partition_id();
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ms_hyperv.vtl = get_vtl();
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if (ms_hyperv.vtl > 0) /* non default VTL */
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pr_info("Linux runs in Hyper-V Virtual Trust Level %d\n", ms_hyperv.vtl);
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ms_hyperv_late_init();
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hyperv_initialized = true;
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return 0;
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}
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early_initcall(hyperv_init);
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bool hv_is_hyperv_initialized(void)
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{
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return hyperv_initialized;
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}
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EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);
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