| Intel MEI |
| ======================= |
| |
| Introduction |
| ======================= |
| |
| The Intel Management Engine (Intel ME) is an isolated and |
| protected computing resource (Coprocessor) residing inside |
| Intel chipsets. The Intel ME provides support for computer/IT |
| management features. |
| The Feature set depends on the Intel chipset SKU. |
| |
| The Intel Management Engine Interface (Intel MEI, previously known |
| as HECI) is the interface between the Host and Intel ME. |
| This interface is exposed to the host as a PCI device. |
| The Intel MEI Driver is in charge of the communication channel |
| between a host application and the ME feature. |
| |
| Each Intel ME feature (Intel ME Client) is addressed by |
| GUID/UUID and each feature defines its own protocol. |
| The protocol is message-based with a header and payload up to |
| 512 bytes. |
| |
| [place holder to URL to protocol definitions] |
| |
| Prominent usage of the Interface is to communicate with |
| Intel Active Management Technology (Intel AMT) |
| implemented in firmware running on the Intel ME. |
| |
| Intel AMT provides the ability to manage a host remotely out-of-band (OOB) |
| even when the host processor has crashed or is in a sleep state. |
| |
| Some examples of Intel AMT usage are: |
| - Monitoring hardware state and platform components |
| - Remote power off/on (useful for green computing or overnight IT maintenance) |
| - OS updates |
| - Storage of useful platform information such as software assets |
| - built-in hardware KVM |
| - selective network isolation of Ethernet and IP protocol flows based on |
| policies set by a remote management console |
| - IDE device redirection from remote management console |
| |
| Intel AMT (OOB) communication is based on SOAP (deprecated |
| starting with Release 6.0) over HTTP/HTTPS or WS-Management protocol |
| over HTTP and HTTPS that are received from a remote |
| management console application. |
| |
| For more information about Intel AMT: |
| http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide/WordDocuments/aboutintelamt.htm |
| |
| |
| MEI Driver |
| ======================= |
| |
| The driver exposes a character device called /dev/mei. |
| |
| An application maintains communication with an ME feature while |
| /dev/mei is open. The binding to a specific features is performed |
| by calling MEI_CONNECT_CLIENT_IOCTL, which passes the desired UUID. |
| The number of instances of an ME feature that can be opened |
| at the same time depends on the ME feature, but most of the |
| features allow only a single instance. |
| |
| |
| The Intel AMT Host Interface (AMTHI) feature requires multiple |
| simultaneous user applications, therefore the MEI driver handles |
| this internally by maintaining request queues for the applications. |
| |
| The driver is oblivious to data that are passed between |
| |
| Because some of the ME features can change the system |
| configuration, the driver by default allows only privileged |
| user to access it. |
| |
| A Code snippet for application communicating with AMTHI client: |
| struct mei_connect_client_data data; |
| fd = open(MEI_DEVICE); |
| |
| data.d.in_client_uuid = AMTHI_UUID; |
| |
| ioctl(fd, IOCTL_MEI_CONNECT_CLIENT, &data); |
| |
| printf(“Ver=%d, MaxLen=%ld\n”, |
| data.d.in_client_uuid.protocol_version, |
| data.d.in_client_uuid.max_msg_length); |
| |
| [...] |
| |
| write(fd, amthi_req_data, amthi_req_data_len); |
| |
| [...] |
| |
| read(fd, &amthi_res_data, amthi_res_data_len); |
| |
| [...] |
| close(fd); |
| |
| ME Applications: |
| ============== |
| |
| 1) Intel Local Management Service (Intel LMS) |
| Applications running locally on the platform communicate with |
| Intel AMT Release 2.0 and later releases in the same way |
| that network applications do via SOAP over HTTP (deprecated |
| starting with Release 6.0) or with WS-Management over SOAP over |
| HTTP. which means that some Intel AMT feature can be access |
| from a local application using same Network interface as for |
| remote application. |
| |
| When a local application sends a message addressed to the local |
| Intel AMT host name, the Local Manageability Service (LMS), |
| which listens for traffic directed to the host name, intercepts |
| the message and routes it to the Intel Management Engine Interface. |
| For more information: |
| http://software.intel.com/sites/manageability/AMT_Implementation_and_ |
| Reference_Guide/WordDocuments/localaccess1.htm |
| |
| The LMS opens a connection using the MEI driver to the LMS |
| FW feature using a defined UUID and then communicates with the |
| feature using a protocol |
| called Intel(R) AMT Port Forwarding Protocol (APF protocol). |
| The protocol is used to maintain multiple sessions with |
| Intel AMT from a single application. |
| See the protocol specification in |
| the Intel(R) AMT Implementation and Reference Guide |
| http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide/HTMLDocuments/MPSDocuments/Intel%20AMT%20Port%20Forwarding%20Protocol%20Reference%20Manual.pdf |
| |
| 2) Intel AMT Remote configuration using a Local Agent: |
| A Local Agent enables IT personnel to configure Intel AMT out-of-the-box |
| without requiring installing additional data to enable setup. |
| The remote configuration process may involve an ISV-developed remote |
| configuration agent that runs on the host. |
| For more information: |
| http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide/WordDocuments/remoteconfigurationwithalocalagent.htm |
| |
| How the Local Agent Works (including Command structs): |
| http://software.intel.com/sites/manageability/AMT_Implementation_and_Reference_Guide/WordDocuments/howthelocalagentsampleworks.htm |
| |
| Intel AMT OS Health Watchdog: |
| ============================= |
| The Intel AMT Watchdog is an OS Health (Hang/Crash) watchdog. |
| Whenever the OS hangs or crashes, Intel AMT will send an event |
| to whoever subscribed to this event. This mechanism means that |
| IT knows when a platform crashes even when there is a hard failure |
| on the host. |
| The AMT Watchdog is composed of two parts: |
| 1) FW Feature - that receives the heartbeats |
| and sends an event when the heartbeats stop. |
| 2) MEI driver – connects to the watchdog (WD) feature, |
| configures the watchdog and sends the heartbeats. |
| |
| The MEI driver configures the Watchdog to expire by default |
| every 120sec unless set by the user using module parameters. |
| The Driver then sends heartbeats every 2sec. |
| |
| If WD feature does not exist (i.e. the connection failed), |
| the MEI driver will disable the sending of heartbeats. |
| |
| Module Parameters |
| ================= |
| watchdog_timeout - the user can use this module parameter |
| to change the watchdog timeout setting. |
| |
| This value sets the Intel AMT watchdog timeout interval in seconds; |
| the default value is 120sec. |
| in order to disable the watchdog activites set the value to 0. |
| Normal values should be between 120 and 65535 |
| |
| Supported Chipsets: |
| ================== |
| 7 Series Chipset Family |
| 6 Series Chipset Family |
| 5 Series Chipset Family |
| 4 Series Chipset Family |
| Mobile 4 Series Chipset Family |
| ICH9 |
| 82946GZ/GL |
| 82G35 Express |
| 82Q963/Q965 |
| 82P965/G965 |
| Mobile PM965/GM965 |
| Mobile GME965/GLE960 |
| 82Q35 Express |
| 82G33/G31/P35/P31 Express |
| 82Q33 Express |
| 82X38/X48 Express |
| |
| --- |
| linux-mei@linux.intel.com |