xref: /linux/drivers/misc/vmw_vmci/vmci_driver.c (revision c95baf12f5077419db01313ab61c2aac007d40cd)
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  */
vmci_get_context_id(void)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  */
vmci_register_vsock_callback(vmci_vsock_cb callback)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 
vmci_call_vsock_callback(bool is_host)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 
vmci_drv_init(void)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 
vmci_drv_exit(void)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");
177