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// 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);
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