arch/arm64/hyperv/mshyperv.c

   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);