1 Intel(R) Management Engine Interface (Intel(R) MEI)
2 ===================================================
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
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
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
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
51 The driver exposes a misc device called /dev/mei.
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.
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.
64 The driver is transparent to data that are passed between firmware feature
67 Because some of the Intel ME features can change the system
68 configuration, the driver by default allows only a privileged
71 A code snippet for an application communicating with Intel AMTHI client:
73 struct mei_connect_client_data data;
74 fd = open(MEI_DEVICE);
76 data.d.in_client_uuid = AMTHI_UUID;
78 ioctl(fd, IOCTL_MEI_CONNECT_CLIENT, &data);
80 printf("Ver=%d, MaxLen=%ld\n",
81 data.d.in_client_uuid.protocol_version,
82 data.d.in_client_uuid.max_msg_length);
86 write(fd, amthi_req_data, amthi_req_data_len);
90 read(fd, &amthi_res_data, amthi_res_data_len);
99 The Intel MEI Driver supports the following IOCTL commands:
100 IOCTL_MEI_CONNECT_CLIENT Connect to firmware Feature (client).
103 struct mei_connect_client_data clientData;
104 ioctl(fd, IOCTL_MEI_CONNECT_CLIENT, &clientData);
107 mei_connect_client_data struct contain the following
110 in_client_uuid - UUID of the FW Feature that needs
113 out_client_properties - Client Properties: MTU and Protocol Version.
116 EINVAL Wrong IOCTL Number
117 ENODEV Device or Connection is not initialized or ready.
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
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).
128 IOCTL_MEI_NOTIFY_SET: enable or disable event notifications
132 ioctl(fd, IOCTL_MEI_NOTIFY_SET, &enable);
137 uint32_t enable[disable] = 0;
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
147 The client must be connected in order to enable notification events
150 IOCTL_MEI_NOTIFY_GET : retrieve event
154 ioctl(fd, IOCTL_MEI_NOTIFY_GET, &event);
157 1 - if an event is pending
158 0 - if there is no even pending
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
168 The client must be connected and event notification has to be enabled
169 in order to receive an event
172 Intel ME Applications
173 =====================
175 1) Intel Local Management Service (Intel LMS)
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.
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"
191 For downloading Intel LMS:
192 http://software.intel.com/en-us/articles/download-the-latest-intel-amt-open-source-drivers/
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
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"
206 2) Intel AMT Remote configuration using a Local Agent
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"
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/
223 Intel AMT OS Health Watchdog
224 ============================
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.
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.
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.
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.
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
261 82G33/G31/P35/P31 Express
266 linux-mei@linux.intel.com