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Based on kernel version 3.19. Page generated on 2015-02-13 21:21 EST.

1	Intel(R) Management Engine Interface (Intel(R) MEI)
2	=======================
4	Introduction
5	=======================
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.
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.
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.
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.
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.
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
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.
44	For more information about Intel AMT:
45	http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide
47	Intel MEI Driver
48	=======================
50	The driver exposes a misc device called /dev/mei.
52	An application maintains communication with an Intel ME feature while
53	/dev/mei is open. The binding to a specific feature is performed by calling
54	MEI_CONNECT_CLIENT_IOCTL, which passes the desired UUID.
55	The number of instances of an Intel ME feature that can be opened
56	at the same time depends on the Intel ME feature, but most of the
57	features allow only a single instance.
59	The Intel AMT Host Interface (Intel AMTHI) feature supports multiple
60	simultaneous user connected applications. The Intel MEI driver
61	handles this internally by maintaining request queues for the applications.
63	The driver is transparent to data that are passed between firmware feature
64	and host application.
66	Because some of the Intel ME features can change the system
67	configuration, the driver by default allows only a privileged
68	user to access it.
70	A code snippet for an application communicating with Intel AMTHI client:
72		struct mei_connect_client_data data;
73		fd = open(MEI_DEVICE);
75		data.d.in_client_uuid = AMTHI_UUID;
77		ioctl(fd, IOCTL_MEI_CONNECT_CLIENT, &data);
79		printf("Ver=%d, MaxLen=%ld\n",
80				data.d.in_client_uuid.protocol_version,
81				data.d.in_client_uuid.max_msg_length);
83		[...]
85		write(fd, amthi_req_data, amthi_req_data_len);
87		[...]
89		read(fd, &amthi_res_data, amthi_res_data_len);
91		[...]
92		close(fd);
95	======
96	The Intel MEI Driver supports the following IOCTL command:
97		IOCTL_MEI_CONNECT_CLIENT	Connect to firmware Feature (client).
99		usage:
100			struct mei_connect_client_data clientData;
101			ioctl(fd, IOCTL_MEI_CONNECT_CLIENT, &clientData);
103		inputs:
104			mei_connect_client_data struct contain the following
105			input field:
107			in_client_uuid -	UUID of the FW Feature that needs
108						to connect to.
109		outputs:
110			out_client_properties - Client Properties: MTU and Protocol Version.
112		error returns:
113			EINVAL	Wrong IOCTL Number
114			ENODEV	Device or Connection is not initialized or ready.
115				(e.g. Wrong UUID)
116			ENOMEM	Unable to allocate memory to client internal data.
117			EFAULT	Fatal Error (e.g. Unable to access user input data)
118			EBUSY	Connection Already Open
120		Notes:
121	        max_msg_length (MTU) in client properties describes the maximum
122	        data that can be sent or received. (e.g. if MTU=2K, can send
123	        requests up to bytes 2k and received responses up to 2k bytes).
125	Intel ME Applications:
126	==============
128	1) Intel Local Management Service (Intel LMS)
130		Applications running locally on the platform communicate with Intel AMT Release
131		2.0 and later releases in the same way that network applications do via SOAP
132		over HTTP (deprecated starting with Release 6.0) or with WS-Management over
133		SOAP over HTTP. This means that some Intel AMT features can be accessed from a
134		local application using the same network interface as a remote application
135		communicating with Intel AMT over the network.
137		When a local application sends a message addressed to the local Intel AMT host
138		name, the Intel LMS, which listens for traffic directed to the host name,
139		intercepts the message and routes it to the Intel MEI.
140		For more information:
141		http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide
142		Under "About Intel AMT" => "Local Access"
144		For downloading Intel LMS:
145		http://software.intel.com/en-us/articles/download-the-latest-intel-amt-open-source-drivers/
147		The Intel LMS opens a connection using the Intel MEI driver to the Intel LMS
148		firmware feature using a defined UUID and then communicates with the feature
149		using a protocol called Intel AMT Port Forwarding Protocol(Intel APF protocol).
150		The protocol is used to maintain multiple sessions with Intel AMT from a
151		single application.
153		See the protocol specification in the Intel AMT Software Development Kit(SDK)
154		http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide
155		Under "SDK Resources" => "Intel(R) vPro(TM) Gateway(MPS)"
156		=> "Information for Intel(R) vPro(TM) Gateway Developers"
157		=> "Description of the Intel AMT Port Forwarding (APF)Protocol"
159	  2) Intel AMT Remote configuration using a Local Agent
160		A Local Agent enables IT personnel to configure Intel AMT out-of-the-box
161		without requiring installing additional data to enable setup. The remote
162		configuration process may involve an ISV-developed remote configuration
163		agent that runs on the host.
164		For more information:
165		http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide
166		Under "Setup and Configuration of Intel AMT" =>
167		"SDK Tools Supporting Setup and Configuration" =>
168		"Using the Local Agent Sample"
170		An open source Intel AMT configuration utility,	implementing a local agent
171		that accesses the Intel MEI driver, can be found here:
172		http://software.intel.com/en-us/articles/download-the-latest-intel-amt-open-source-drivers/
175	Intel AMT OS Health Watchdog:
176	=============================
177	The Intel AMT Watchdog is an OS Health (Hang/Crash) watchdog.
178	Whenever the OS hangs or crashes, Intel AMT will send an event
179	to any subscriber to this event. This mechanism means that
180	IT knows when a platform crashes even when there is a hard failure on the host.
182	The Intel AMT Watchdog is composed of two parts:
183		1) Firmware feature - receives the heartbeats
184		   and sends an event when the heartbeats stop.
185		2) Intel MEI driver - connects to the watchdog feature, configures the
186		   watchdog and sends the heartbeats.
188	The Intel MEI driver uses the kernel watchdog API to configure the Intel AMT
189	Watchdog and to send heartbeats to it. The default timeout of the
190	watchdog is 120 seconds.
192	If the Intel AMT Watchdog feature does not exist (i.e. the connection failed),
193	the Intel MEI driver will disable the sending of heartbeats.
195	Supported Chipsets:
196	==================
197	7 Series Chipset Family
198	6 Series Chipset Family
199	5 Series Chipset Family
200	4 Series Chipset Family
201	Mobile 4 Series Chipset Family
202	ICH9
203	82946GZ/GL
204	82G35 Express
205	82Q963/Q965
206	82P965/G965
207	Mobile PM965/GM965
208	Mobile GME965/GLE960
209	82Q35 Express
210	82G33/G31/P35/P31 Express
211	82Q33 Express
212	82X38/X48 Express
214	---
215	linux-mei@linux.intel.com
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