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 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 = generate_guest_id(0, LINUX_VERSION_CODE, 0);
  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_ONLINE_DYN, "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);