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A Method of improving the communication mechanism between UEFI and BMC

IP.com Disclosure Number: IPCOM000217111D
Publication Date: 2012-May-03

Publishing Venue

The IP.com Prior Art Database

Abstract

This article puts forward a new method to improve the communication mechanism between UEFI(Unified Extensible Firmware Interface) and BMC:Instead of using the legacy KCS and I2C bus, a stack of memory space is used for UEFI and BMC to communicate and share the data which can be accessed by both. In addition, a filesystem is designed with fixed size blocks in the shared memory.By using mutex, both UEFI and BMC can access file or data more effectively and accurately.

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A Method of improving the communication mechanism between UEFI and BMC

The general communication mechanism between UEFI(Unified Extensible Firmware Interface) and BMC is on the basis of IPMI protocol via I2C and KCS busUEFI sends IPMI command to BMC. After BMC receives IPMI commands, it will return result to UEFI.

The deficiency of the current method is that the booting process of UEFI largely depends on the initialization speed of IPMI stack

within BMC, the communication can not start until the IPMI stack gets ready. However, the setting-up of IPMI stack is typically quite time-consuming, as the IPMI protocol is relatively complicated.

The object for monitoring in the server is dramatically growing such as the temperature, fan speed, different kinds of hardware information and the critical status of the server. All these server data are sent to the host by the IPMI command. Therefore, the transferring efficiency of IPMI protocol is one of the essential bottleneck to impact the server management . IPMI messaging uses a request/response protocol, in the actual implementation; the maximal message size of an IPMI command is limited, such as 245 bytes. To Transfer a large file it requires several times of IPMI communication between BMC and UEFI . Obviously, this is not the efficient way.

In a word current communication mechanism affects the booting speed of system and lowers the customer satisfaction . Nothing is more frustrated than waiting for server booting up for a long time.

To resolve these bottlenecks, a new method of communication between UEFI and BMC is put forward. The abstract of this method is:Instead of using the KCS and I2C bus, a stack of memory space (such as 4KB, even bigger) is used for UEFI and BMC to communicate and share the data which can be accessed by both. In addition,
a filesystem is designed with fixed size blocks in the shared memory.By using mutex, both UEFI and BMC can access file or data more effectively and accurately.

The advantages of new method are as following:

Speeding up the booting up of UEFI. UEFI can communicate with BMC and share data without depending on the setting-up of


1.

IPMI stack reducing the boot time required. Typically, UEFI could communicate with BMC one minute earlier by using the new method.

Improving the efficiency of communication


2.

a) More effective on large file transferring. When large file is exchanged between BMC and UEFI. quite a lot of IPMI communications will be established . This will add the extra time during the process of initialization of BMC, then slow down

1


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the OS boot-up in a whole


b) Much faster on UEFI data searching and transferring.

3. Reducing the development time and debug cost. Share memory can be Memory accessed by BMC, and UEFI regards it as a
PCI device, the access for both UEFI and BMC is very simple.

To make sure the innovativeness of this new method, The set of keywords 'IPMI','BMC','memory','BIOS' is searched.

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