drivers/misc/vmw_vmci/vmci_driver.c

   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
  18 static bool vmci_disable_host;
  19 module_param_named(disable_host, vmci_disable_host, bool, 0);
  20 MODULE_PARM_DESC(disable_host,
  21                  "Disable driver host personality (default=enabled)");
  22
  23 static bool vmci_disable_guest;
  24 module_param_named(disable_guest, vmci_disable_guest, bool, 0);
  25 MODULE_PARM_DESC(disable_guest,
  26                  "Disable driver guest personality (default=enabled)");
  27
  28 static bool vmci_guest_personality_initialized;
  29 static bool vmci_host_personality_initialized;
  30
  31 static DEFINE_MUTEX(vmci_vsock_mutex); /* protects vmci_vsock_transport_cb */
  32 static vmci_vsock_cb vmci_vsock_transport_cb;
  33 static 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  */
  41 u32 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 }
  50 EXPORT_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  */
  61 int 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
  87 out:
  88         mutex_unlock(&vmci_vsock_mutex);
  89         return err;
  90 }
  91 EXPORT_SYMBOL_GPL(vmci_register_vsock_callback);
  92
  93 void 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);
 111 out:
 112         mutex_unlock(&vmci_vsock_mutex);
 113 }
 114
 115 static 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 }
 159 module_init(vmci_drv_init);
 160
 161 static 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 }
 171 module_exit(vmci_drv_exit);
 172
 173 MODULE_AUTHOR("VMware, Inc.");
 174 MODULE_DESCRIPTION("VMware Virtual Machine Communication Interface.");
 175 MODULE_VERSION("1.1.6.0-k");
 176 MODULE_LICENSE("GPL v2");