LXR linux/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
  20static bool hyperv_initialized;
  21
  22static 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
  81early_initcall(hyperv_init);
  82
  83bool hv_is_hyperv_initialized(void)
  84{
  85        return hyperv_initialized;
  86}
  87EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized);
  88