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 ======================= 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 Intel MEI Driver 48 ======================= 49 50 The driver exposes a misc device called /dev/mei. 51 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. 58 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. 62 63 The driver is transparent to data that are passed between firmware feature 64 and host application. 65 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. 69 70 A code snippet for an application communicating with Intel AMTHI client: 71 72 struct mei_connect_client_data data; 73 fd = open(MEI_DEVICE); 74 75 data.d.in_client_uuid = AMTHI_UUID; 76 77 ioctl(fd, IOCTL_MEI_CONNECT_CLIENT, &data); 78 79 printf("Ver=%d, MaxLen=%ld\n", 80 data.d.in_client_uuid.protocol_version, 81 data.d.in_client_uuid.max_msg_length); 82 83 [...] 84 85 write(fd, amthi_req_data, amthi_req_data_len); 86 87 [...] 88 89 read(fd, &amthi_res_data, amthi_res_data_len); 90 91 [...] 92 close(fd); 93 94 IOCTL: 95 ====== 96 The Intel MEI Driver supports the following IOCTL command: 97 IOCTL_MEI_CONNECT_CLIENT Connect to firmware Feature (client). 98 99 usage: 100 struct mei_connect_client_data clientData; 101 ioctl(fd, IOCTL_MEI_CONNECT_CLIENT, &clientData); 102 103 inputs: 104 mei_connect_client_data struct contain the following 105 input field: 106 107 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. 111 112 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 119 120 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). 124 125 Intel ME Applications: 126 ============== 127 128 1) Intel Local Management Service (Intel LMS) 129 130 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. 136 137 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" 143 144 For downloading Intel LMS: 145 http://software.intel.com/en-us/articles/download-the-latest-intel-amt-open-source-drivers/ 146 147 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. 152 153 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" 158 159 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" 169 170 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/ 173 174 175 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. 181 182 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. 187 188 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. 191 192 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. 194 195 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 213 214 --- 215 firstname.lastname@example.org