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Based on kernel version 4.3. Page generated on 2015-11-02 12:50 EST.

1	Intel(R) Management Engine Interface (Intel(R) MEI)
2	===================================================
3	
4	Introduction
5	============
6	
7	The Intel Management Engine (Intel ME) is an isolated and protected computing
8	resource (Co-processor) residing inside certain Intel chipsets. The Intel ME
9	provides support for computer/IT management features. The feature set
10	depends on the Intel chipset SKU.
11	
12	The Intel Management Engine Interface (Intel MEI, previously known as HECI)
13	is the interface between the Host and Intel ME. This interface is exposed
14	to the host as a PCI device. The Intel MEI Driver is in charge of the
15	communication channel between a host application and the Intel ME feature.
16	
17	Each Intel ME feature (Intel ME Client) is addressed by a GUID/UUID and
18	each client has its own protocol. The protocol is message-based with a
19	header and payload up to 512 bytes.
20	
21	Prominent usage of the Intel ME Interface is to communicate with Intel(R)
22	Active Management Technology (Intel AMT) implemented in firmware running on
23	the Intel ME.
24	
25	Intel AMT provides the ability to manage a host remotely out-of-band (OOB)
26	even when the operating system running on the host processor has crashed or
27	is in a sleep state.
28	
29	Some examples of Intel AMT usage are:
30	   - Monitoring hardware state and platform components
31	   - Remote power off/on (useful for green computing or overnight IT
32	     maintenance)
33	   - OS updates
34	   - Storage of useful platform information such as software assets
35	   - Built-in hardware KVM
36	   - Selective network isolation of Ethernet and IP protocol flows based
37	     on policies set by a remote management console
38	   - IDE device redirection from remote management console
39	
40	Intel AMT (OOB) communication is based on SOAP (deprecated
41	starting with Release 6.0) over HTTP/S or WS-Management protocol over
42	HTTP/S that are received from a remote management console application.
43	
44	For more information about Intel AMT:
45	http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide
46	
47	
48	Intel MEI Driver
49	================
50	
51	The driver exposes a misc device called /dev/mei.
52	
53	An application maintains communication with an Intel ME feature while
54	/dev/mei is open. The binding to a specific feature is performed by calling
55	MEI_CONNECT_CLIENT_IOCTL, which passes the desired UUID.
56	The number of instances of an Intel ME feature that can be opened
57	at the same time depends on the Intel ME feature, but most of the
58	features allow only a single instance.
59	
60	The Intel AMT Host Interface (Intel AMTHI) feature supports multiple
61	simultaneous user connected applications. The Intel MEI driver
62	handles this internally by maintaining request queues for the applications.
63	
64	The driver is transparent to data that are passed between firmware feature
65	and host application.
66	
67	Because some of the Intel ME features can change the system
68	configuration, the driver by default allows only a privileged
69	user to access it.
70	
71	A code snippet for an application communicating with Intel AMTHI client:
72	
73		struct mei_connect_client_data data;
74		fd = open(MEI_DEVICE);
75	
76		data.d.in_client_uuid = AMTHI_UUID;
77	
78		ioctl(fd, IOCTL_MEI_CONNECT_CLIENT, &data);
79	
80		printf("Ver=%d, MaxLen=%ld\n",
81				data.d.in_client_uuid.protocol_version,
82				data.d.in_client_uuid.max_msg_length);
83	
84		[...]
85	
86		write(fd, amthi_req_data, amthi_req_data_len);
87	
88		[...]
89	
90		read(fd, &amthi_res_data, amthi_res_data_len);
91	
92		[...]
93		close(fd);
94	
95	
96	IOCTL
97	=====
98	
99	The Intel MEI Driver supports the following IOCTL commands:
100		IOCTL_MEI_CONNECT_CLIENT	Connect to firmware Feature (client).
101	
102		usage:
103			struct mei_connect_client_data clientData;
104			ioctl(fd, IOCTL_MEI_CONNECT_CLIENT, &clientData);
105	
106		inputs:
107			mei_connect_client_data struct contain the following
108			input field:
109	
110			in_client_uuid -	UUID of the FW Feature that needs
111						to connect to.
112		outputs:
113			out_client_properties - Client Properties: MTU and Protocol Version.
114	
115		error returns:
116			EINVAL	Wrong IOCTL Number
117			ENODEV	Device or Connection is not initialized or ready.
118				(e.g. Wrong UUID)
119			ENOMEM	Unable to allocate memory to client internal data.
120			EFAULT	Fatal Error (e.g. Unable to access user input data)
121			EBUSY	Connection Already Open
122	
123		Notes:
124	        max_msg_length (MTU) in client properties describes the maximum
125	        data that can be sent or received. (e.g. if MTU=2K, can send
126	        requests up to bytes 2k and received responses up to 2k bytes).
127	
128		IOCTL_MEI_NOTIFY_SET: enable or disable event notifications
129	
130		Usage:
131			uint32_t enable;
132			ioctl(fd, IOCTL_MEI_NOTIFY_SET, &enable);
133	
134		Inputs:
135			uint32_t enable = 1;
136			or
137			uint32_t enable[disable] = 0;
138	
139		Error returns:
140			EINVAL	Wrong IOCTL Number
141			ENODEV	Device  is not initialized or the client not connected
142			ENOMEM	Unable to allocate memory to client internal data.
143			EFAULT	Fatal Error (e.g. Unable to access user input data)
144			EOPNOTSUPP if the device doesn't support the feature
145	
146		Notes:
147		The client must be connected in order to enable notification events
148	
149	
150		IOCTL_MEI_NOTIFY_GET : retrieve event
151	
152		Usage:
153			uint32_t event;
154			ioctl(fd, IOCTL_MEI_NOTIFY_GET, &event);
155	
156		Outputs:
157			1 - if an event is pending
158			0 - if there is no even pending
159	
160		Error returns:
161			EINVAL	Wrong IOCTL Number
162			ENODEV	Device is not initialized or the client not connected
163			ENOMEM	Unable to allocate memory to client internal data.
164			EFAULT	Fatal Error (e.g. Unable to access user input data)
165			EOPNOTSUPP if the device doesn't support the feature
166	
167		Notes:
168		The client must be connected and event notification has to be enabled
169		in order to receive an event
170	
171	
172	Intel ME Applications
173	=====================
174	
175		1) Intel Local Management Service (Intel LMS)
176	
177		   Applications running locally on the platform communicate with Intel AMT Release
178		   2.0 and later releases in the same way that network applications do via SOAP
179		   over HTTP (deprecated starting with Release 6.0) or with WS-Management over
180		   SOAP over HTTP. This means that some Intel AMT features can be accessed from a
181		   local application using the same network interface as a remote application
182		   communicating with Intel AMT over the network.
183	
184		   When a local application sends a message addressed to the local Intel AMT host
185		   name, the Intel LMS, which listens for traffic directed to the host name,
186		   intercepts the message and routes it to the Intel MEI.
187		   For more information:
188		   http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide
189		   Under "About Intel AMT" => "Local Access"
190	
191		   For downloading Intel LMS:
192		   http://software.intel.com/en-us/articles/download-the-latest-intel-amt-open-source-drivers/
193	
194		   The Intel LMS opens a connection using the Intel MEI driver to the Intel LMS
195		   firmware feature using a defined UUID and then communicates with the feature
196		   using a protocol called Intel AMT Port Forwarding Protocol (Intel APF protocol).
197		   The protocol is used to maintain multiple sessions with Intel AMT from a
198		   single application.
199	
200		   See the protocol specification in the Intel AMT Software Development Kit (SDK)
201		   http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide
202		   Under "SDK Resources" => "Intel(R) vPro(TM) Gateway (MPS)"
203		   => "Information for Intel(R) vPro(TM) Gateway Developers"
204		   => "Description of the Intel AMT Port Forwarding (APF) Protocol"
205	
206		2) Intel AMT Remote configuration using a Local Agent
207	
208		   A Local Agent enables IT personnel to configure Intel AMT out-of-the-box
209		   without requiring installing additional data to enable setup. The remote
210		   configuration process may involve an ISV-developed remote configuration
211		   agent that runs on the host.
212		   For more information:
213		   http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide
214		   Under "Setup and Configuration of Intel AMT" =>
215		   "SDK Tools Supporting Setup and Configuration" =>
216		   "Using the Local Agent Sample"
217	
218		   An open source Intel AMT configuration utility,	implementing a local agent
219		   that accesses the Intel MEI driver, can be found here:
220		   http://software.intel.com/en-us/articles/download-the-latest-intel-amt-open-source-drivers/
221	
222	
223	Intel AMT OS Health Watchdog
224	============================
225	
226	The Intel AMT Watchdog is an OS Health (Hang/Crash) watchdog.
227	Whenever the OS hangs or crashes, Intel AMT will send an event
228	to any subscriber to this event. This mechanism means that
229	IT knows when a platform crashes even when there is a hard failure on the host.
230	
231	The Intel AMT Watchdog is composed of two parts:
232		1) Firmware feature - receives the heartbeats
233		   and sends an event when the heartbeats stop.
234		2) Intel MEI driver - connects to the watchdog feature, configures the
235		   watchdog and sends the heartbeats.
236	
237	The Intel MEI driver uses the kernel watchdog API to configure the Intel AMT
238	Watchdog and to send heartbeats to it. The default timeout of the
239	watchdog is 120 seconds.
240	
241	If the Intel AMT Watchdog feature does not exist (i.e. the connection failed),
242	the Intel MEI driver will disable the sending of heartbeats.
243	
244	
245	Supported Chipsets
246	==================
247	
248	7 Series Chipset Family
249	6 Series Chipset Family
250	5 Series Chipset Family
251	4 Series Chipset Family
252	Mobile 4 Series Chipset Family
253	ICH9
254	82946GZ/GL
255	82G35 Express
256	82Q963/Q965
257	82P965/G965
258	Mobile PM965/GM965
259	Mobile GME965/GLE960
260	82Q35 Express
261	82G33/G31/P35/P31 Express
262	82Q33 Express
263	82X38/X48 Express
264	
265	---
266	linux-mei@linux.intel.com
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