Quelle  vmci_driver.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-only
/*
 * VMware VMCI Driver
 *
 * Copyright (C) 2012 VMware, Inc. All rights reserved.
 */

#include <linux/vmw_vmci_defs.h>
#include <linux/vmw_vmci_api.h>
#include <linux/atomic.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>

#include "vmci_driver.h"
#include "vmci_event.h"

static bool vmci_disable_host;
module_param_named(disable_host, vmci_disable_host, bool, 0);
MODULE_PARM_DESC(disable_host,
   "Disable driver host personality (default=enabled)");

static bool vmci_disable_guest;
module_param_named(disable_guest, vmci_disable_guest, bool, 0);
MODULE_PARM_DESC(disable_guest,
   "Disable driver guest personality (default=enabled)");

static bool vmci_guest_personality_initialized;
static bool vmci_host_personality_initialized;

static DEFINE_MUTEX(vmci_vsock_mutex); /* protects vmci_vsock_transport_cb */
static vmci_vsock_cb vmci_vsock_transport_cb;
static bool vmci_vsock_cb_host_called;

/*
 * vmci_get_context_id() - Gets the current context ID.
 *
 * Returns the current context ID.  Note that since this is accessed only
 * from code running in the host, this always returns the host context ID.
 */
u32 vmci_get_context_id(void)
{
 if (vmci_guest_code_active())
  return vmci_get_vm_context_id();
 else if (vmci_host_code_active())
  return VMCI_HOST_CONTEXT_ID;

 return VMCI_INVALID_ID;
}
EXPORT_SYMBOL_GPL(vmci_get_context_id);

/*
 * vmci_register_vsock_callback() - Register the VSOCK vmci_transport callback.
 *
 * The callback will be called when the first host or guest becomes active,
 * or if they are already active when this function is called.
 * To unregister the callback, call this function with NULL parameter.
 *
 * Returns 0 on success. -EBUSY if a callback is already registered.
 */
int vmci_register_vsock_callback(vmci_vsock_cb callback)
{
 int err = 0;

 mutex_lock(&vmci_vsock_mutex);

 if (vmci_vsock_transport_cb && callback) {
  err = -EBUSY;
  goto out;
 }

 vmci_vsock_transport_cb = callback;

 if (!vmci_vsock_transport_cb) {
  vmci_vsock_cb_host_called = false;
  goto out;
 }

 if (vmci_guest_code_active())
  vmci_vsock_transport_cb(false);

 if (vmci_host_users() > 0) {
  vmci_vsock_cb_host_called = true;
  vmci_vsock_transport_cb(true);
 }

out:
 mutex_unlock(&vmci_vsock_mutex);
 return err;
}
EXPORT_SYMBOL_GPL(vmci_register_vsock_callback);

void vmci_call_vsock_callback(bool is_host)
{
 mutex_lock(&vmci_vsock_mutex);

 if (!vmci_vsock_transport_cb)
  goto out;

 /* In the host, this function could be called multiple times,
 * but we want to register it only once.
 */
 if (is_host) {
  if (vmci_vsock_cb_host_called)
   goto out;

  vmci_vsock_cb_host_called = true;
 }

 vmci_vsock_transport_cb(is_host);
out:
 mutex_unlock(&vmci_vsock_mutex);
}

static int __init vmci_drv_init(void)
{
 int vmci_err;
 int error;

 vmci_err = vmci_event_init();
 if (vmci_err < VMCI_SUCCESS) {
  pr_err("Failed to initialize VMCIEvent (result=%d)\n",
         vmci_err);
  return -EINVAL;
 }

 if (!vmci_disable_guest) {
  error = vmci_guest_init();
  if (error) {
   pr_warn("Failed to initialize guest personality (err=%d)\n",
    error);
  } else {
   vmci_guest_personality_initialized = true;
   pr_info("Guest personality initialized and is %s\n",
    vmci_guest_code_active() ?
    "active" : "inactive");
  }
 }

 if (!vmci_disable_host) {
  error = vmci_host_init();
  if (error) {
   pr_warn("Unable to initialize host personality (err=%d)\n",
    error);
  } else {
   vmci_host_personality_initialized = true;
   pr_info("Initialized host personality\n");
  }
 }

 if (!vmci_guest_personality_initialized &&
     !vmci_host_personality_initialized) {
  vmci_event_exit();
  return -ENODEV;
 }

 return 0;
}
module_init(vmci_drv_init);

static void __exit vmci_drv_exit(void)
{
 if (vmci_guest_personality_initialized)
  vmci_guest_exit();

 if (vmci_host_personality_initialized)
  vmci_host_exit();

 vmci_event_exit();
}
module_exit(vmci_drv_exit);

MODULE_AUTHOR("VMware, Inc.");
MODULE_DESCRIPTION("VMware Virtual Machine Communication Interface.");
MODULE_VERSION("1.1.6.0-k");
MODULE_LICENSE("GPL v2");