misc/vmw_vmci/vmci_driver.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * VMware VMCI Driver
0004  *
0005  * Copyright (C) 2012 VMware, Inc. All rights reserved.
0006  */
0007
0008 #include <linux/vmw_vmci_defs.h>
0009 #include <linux/vmw_vmci_api.h>
0010 #include <linux/atomic.h>
0011 #include <linux/kernel.h>
0012 #include <linux/module.h>
0013 #include <linux/init.h>
0014
0015 #include "vmci_driver.h"
0016 #include "vmci_event.h"
0017
0018 static bool vmci_disable_host;
0019 module_param_named(disable_host, vmci_disable_host, bool, 0);
0020 MODULE_PARM_DESC(disable_host,
0021          "Disable driver host personality (default=enabled)");
0022
0023 static bool vmci_disable_guest;
0024 module_param_named(disable_guest, vmci_disable_guest, bool, 0);
0025 MODULE_PARM_DESC(disable_guest,
0026          "Disable driver guest personality (default=enabled)");
0027
0028 static bool vmci_guest_personality_initialized;
0029 static bool vmci_host_personality_initialized;
0030
0031 static DEFINE_MUTEX(vmci_vsock_mutex); /* protects vmci_vsock_transport_cb */
0032 static vmci_vsock_cb vmci_vsock_transport_cb;
0033 static bool vmci_vsock_cb_host_called;
0034
0035 /*
0036  * vmci_get_context_id() - Gets the current context ID.
0037  *
0038  * Returns the current context ID.  Note that since this is accessed only
0039  * from code running in the host, this always returns the host context ID.
0040  */
0041 u32 vmci_get_context_id(void)
0042 {
0043     if (vmci_guest_code_active())
0044         return vmci_get_vm_context_id();
0045     else if (vmci_host_code_active())
0046         return VMCI_HOST_CONTEXT_ID;
0047
0048     return VMCI_INVALID_ID;
0049 }
0050 EXPORT_SYMBOL_GPL(vmci_get_context_id);
0051
0052 /*
0053  * vmci_register_vsock_callback() - Register the VSOCK vmci_transport callback.
0054  *
0055  * The callback will be called when the first host or guest becomes active,
0056  * or if they are already active when this function is called.
0057  * To unregister the callback, call this function with NULL parameter.
0058  *
0059  * Returns 0 on success. -EBUSY if a callback is already registered.
0060  */
0061 int vmci_register_vsock_callback(vmci_vsock_cb callback)
0062 {
0063     int err = 0;
0064
0065     mutex_lock(&vmci_vsock_mutex);
0066
0067     if (vmci_vsock_transport_cb && callback) {
0068         err = -EBUSY;
0069         goto out;
0070     }
0071
0072     vmci_vsock_transport_cb = callback;
0073
0074     if (!vmci_vsock_transport_cb) {
0075         vmci_vsock_cb_host_called = false;
0076         goto out;
0077     }
0078
0079     if (vmci_guest_code_active())
0080         vmci_vsock_transport_cb(false);
0081
0082     if (vmci_host_users() > 0) {
0083         vmci_vsock_cb_host_called = true;
0084         vmci_vsock_transport_cb(true);
0085     }
0086
0087 out:
0088     mutex_unlock(&vmci_vsock_mutex);
0089     return err;
0090 }
0091 EXPORT_SYMBOL_GPL(vmci_register_vsock_callback);
0092
0093 void vmci_call_vsock_callback(bool is_host)
0094 {
0095     mutex_lock(&vmci_vsock_mutex);
0096
0097     if (!vmci_vsock_transport_cb)
0098         goto out;
0099
0100     /* In the host, this function could be called multiple times,
0101      * but we want to register it only once.
0102      */
0103     if (is_host) {
0104         if (vmci_vsock_cb_host_called)
0105             goto out;
0106
0107         vmci_vsock_cb_host_called = true;
0108     }
0109
0110     vmci_vsock_transport_cb(is_host);
0111 out:
0112     mutex_unlock(&vmci_vsock_mutex);
0113 }
0114
0115 static int __init vmci_drv_init(void)
0116 {
0117     int vmci_err;
0118     int error;
0119
0120     vmci_err = vmci_event_init();
0121     if (vmci_err < VMCI_SUCCESS) {
0122         pr_err("Failed to initialize VMCIEvent (result=%d)\n",
0123                vmci_err);
0124         return -EINVAL;
0125     }
0126
0127     if (!vmci_disable_guest) {
0128         error = vmci_guest_init();
0129         if (error) {
0130             pr_warn("Failed to initialize guest personality (err=%d)\n",
0131                 error);
0132         } else {
0133             vmci_guest_personality_initialized = true;
0134             pr_info("Guest personality initialized and is %s\n",
0135                 vmci_guest_code_active() ?
0136                 "active" : "inactive");
0137         }
0138     }
0139
0140     if (!vmci_disable_host) {
0141         error = vmci_host_init();
0142         if (error) {
0143             pr_warn("Unable to initialize host personality (err=%d)\n",
0144                 error);
0145         } else {
0146             vmci_host_personality_initialized = true;
0147             pr_info("Initialized host personality\n");
0148         }
0149     }
0150
0151     if (!vmci_guest_personality_initialized &&
0152         !vmci_host_personality_initialized) {
0153         vmci_event_exit();
0154         return -ENODEV;
0155     }
0156
0157     return 0;
0158 }
0159 module_init(vmci_drv_init);
0160
0161 static void __exit vmci_drv_exit(void)
0162 {
0163     if (vmci_guest_personality_initialized)
0164         vmci_guest_exit();
0165
0166     if (vmci_host_personality_initialized)
0167         vmci_host_exit();
0168
0169     vmci_event_exit();
0170 }
0171 module_exit(vmci_drv_exit);
0172
0173 MODULE_AUTHOR("VMware, Inc.");
0174 MODULE_DESCRIPTION("VMware Virtual Machine Communication Interface.");
0175 MODULE_VERSION("1.1.6.0-k");
0176 MODULE_LICENSE("GPL v2");