linux/drivers/misc/vmw_vmci/vmci_driver.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * VMware VMCI Driver
   4 *
   5 * Copyright (C) 2012 VMware, Inc. All rights reserved.
   6 */
   7
   8#include <linux/vmw_vmci_defs.h>
   9#include <linux/vmw_vmci_api.h>
  10#include <linux/atomic.h>
  11#include <linux/kernel.h>
  12#include <linux/module.h>
  13#include <linux/init.h>
  14
  15#include "vmci_driver.h"
  16#include "vmci_event.h"
  17
  18static bool vmci_disable_host;
  19module_param_named(disable_host, vmci_disable_host, bool, 0);
  20MODULE_PARM_DESC(disable_host,
  21                 "Disable driver host personality (default=enabled)");
  22
  23static bool vmci_disable_guest;
  24module_param_named(disable_guest, vmci_disable_guest, bool, 0);
  25MODULE_PARM_DESC(disable_guest,
  26                 "Disable driver guest personality (default=enabled)");
  27
  28static bool vmci_guest_personality_initialized;
  29static bool vmci_host_personality_initialized;
  30
  31static DEFINE_MUTEX(vmci_vsock_mutex); /* protects vmci_vsock_transport_cb */
  32static vmci_vsock_cb vmci_vsock_transport_cb;
  33static bool vmci_vsock_cb_host_called;
  34
  35/*
  36 * vmci_get_context_id() - Gets the current context ID.
  37 *
  38 * Returns the current context ID.  Note that since this is accessed only
  39 * from code running in the host, this always returns the host context ID.
  40 */
  41u32 vmci_get_context_id(void)
  42{
  43        if (vmci_guest_code_active())
  44                return vmci_get_vm_context_id();
  45        else if (vmci_host_code_active())
  46                return VMCI_HOST_CONTEXT_ID;
  47
  48        return VMCI_INVALID_ID;
  49}
  50EXPORT_SYMBOL_GPL(vmci_get_context_id);
  51
  52/*
  53 * vmci_register_vsock_callback() - Register the VSOCK vmci_transport callback.
  54 *
  55 * The callback will be called when the first host or guest becomes active,
  56 * or if they are already active when this function is called.
  57 * To unregister the callback, call this function with NULL parameter.
  58 *
  59 * Returns 0 on success. -EBUSY if a callback is already registered.
  60 */
  61int vmci_register_vsock_callback(vmci_vsock_cb callback)
  62{
  63        int err = 0;
  64
  65        mutex_lock(&vmci_vsock_mutex);
  66
  67        if (vmci_vsock_transport_cb && callback) {
  68                err = -EBUSY;
  69                goto out;
  70        }
  71
  72        vmci_vsock_transport_cb = callback;
  73
  74        if (!vmci_vsock_transport_cb) {
  75                vmci_vsock_cb_host_called = false;
  76                goto out;
  77        }
  78
  79        if (vmci_guest_code_active())
  80                vmci_vsock_transport_cb(false);
  81
  82        if (vmci_host_users() > 0) {
  83                vmci_vsock_cb_host_called = true;
  84                vmci_vsock_transport_cb(true);
  85        }
  86
  87out:
  88        mutex_unlock(&vmci_vsock_mutex);
  89        return err;
  90}
  91EXPORT_SYMBOL_GPL(vmci_register_vsock_callback);
  92
  93void vmci_call_vsock_callback(bool is_host)
  94{
  95        mutex_lock(&vmci_vsock_mutex);
  96
  97        if (!vmci_vsock_transport_cb)
  98                goto out;
  99
 100        /* In the host, this function could be called multiple times,
 101         * but we want to register it only once.
 102         */
 103        if (is_host) {
 104                if (vmci_vsock_cb_host_called)
 105                        goto out;
 106
 107                vmci_vsock_cb_host_called = true;
 108        }
 109
 110        vmci_vsock_transport_cb(is_host);
 111out:
 112        mutex_unlock(&vmci_vsock_mutex);
 113}
 114
 115static int __init vmci_drv_init(void)
 116{
 117        int vmci_err;
 118        int error;
 119
 120        vmci_err = vmci_event_init();
 121        if (vmci_err < VMCI_SUCCESS) {
 122                pr_err("Failed to initialize VMCIEvent (result=%d)\n",
 123                       vmci_err);
 124                return -EINVAL;
 125        }
 126
 127        if (!vmci_disable_guest) {
 128                error = vmci_guest_init();
 129                if (error) {
 130                        pr_warn("Failed to initialize guest personality (err=%d)\n",
 131                                error);
 132                } else {
 133                        vmci_guest_personality_initialized = true;
 134                        pr_info("Guest personality initialized and is %s\n",
 135                                vmci_guest_code_active() ?
 136                                "active" : "inactive");
 137                }
 138        }
 139
 140        if (!vmci_disable_host) {
 141                error = vmci_host_init();
 142                if (error) {
 143                        pr_warn("Unable to initialize host personality (err=%d)\n",
 144                                error);
 145                } else {
 146                        vmci_host_personality_initialized = true;
 147                        pr_info("Initialized host personality\n");
 148                }
 149        }
 150
 151        if (!vmci_guest_personality_initialized &&
 152            !vmci_host_personality_initialized) {
 153                vmci_event_exit();
 154                return -ENODEV;
 155        }
 156
 157        return 0;
 158}
 159module_init(vmci_drv_init);
 160
 161static void __exit vmci_drv_exit(void)
 162{
 163        if (vmci_guest_personality_initialized)
 164                vmci_guest_exit();
 165
 166        if (vmci_host_personality_initialized)
 167                vmci_host_exit();
 168
 169        vmci_event_exit();
 170}
 171module_exit(vmci_drv_exit);
 172
 173MODULE_AUTHOR("VMware, Inc.");
 174MODULE_DESCRIPTION("VMware Virtual Machine Communication Interface.");
 175MODULE_VERSION("1.1.6.0-k");
 176MODULE_LICENSE("GPL v2");
 177