Kernel Changes for IBM iSeries Logical Partition

IBM has ported Linux to the PowerPC based iSeries system. There are a number of features of this port that make it technically interesting and that exploit features of the PowerPC processor. For example, a single iSeries system can be logically partitioned into up to 32 separate system images, and where multiple Linux and OS/400 partitions can share a single processor. The goal of the port was to live within the standard PowerPC kernel tree, while supporting the logical partitioning of the system. To everything outside the kernel, this is a standard PowerPC implementation, identical to the IBM RS/6000 or Macintosh implementations.

The iSeries implementation required some changes, such as running the entire kernel in relocate mode, which were mandated by integrity checks that guarantee one partition cannot corrupt another. In addition to integrity changes, the iSeries implementation provides a number of unique I/O functions, such as a high-speed, bus level virtual ethernet, and virtual disk, tape, CD and console provided by one partition to another.

This talk is aimed at a technical audience familiar with the Linux kernel. It will cover the overall architecture of the iSeries Linux implementation, and discuss the low level implementation of both integrity and I/O functions. It will be of particular interest to anyone implementing similar shared operating system environments, such as VMWare or User Mode Linux