GSOC 2013 - Paravirtualization of RTEMS

The goal is to run RTEMS virtual on POK inside a software partition.

The ​Proposal will be open for everyone, after the application deadline (May 3, 2013).

Partitioned OS Kernel - POK

AADL

RTEMS

Configuration

The only change to the RTEMS configuration scripts, will be additional names for the --enable-rtemsbsp= option.

= Discarded proposals =

To configure RTEMS for virtual execution of the binary, a new flag is introduced.

• --enable-virt:

It tells autoconf to assume a different directory structure. The other configuration parameter, which are deduce from --target and --enable-rtemsbsp, are not touched.

Directory structure

The CPU dependent code is split up in virtualization sensitive and unsensitive parts. The unsensitive parts go in cpukit/score/cpu/${arch}/ the sensitive parts go into c/src/lib/libcpu/${arch}/${arch}virt/.

The CPU is selected through the BSP, hence additional virtual BSPs of the form ${bsp_name}virt are introduced.

Therefore no changes to the configuration scripts besides the additional BSP names are necessary. The target names stay the same.

In the end there is one virtual CPU model and one BSP per virtualized architecture.

= Discarded proposals =

To prevent cluttering the BSP and CPU directories with additional virtual CPU models, a collective directory is added.

• c/src/lib/libbsp/virt/<arch>/<bsp_name>
• cpukit/score/cpu/virt/<arch>

The behaviour inside these directories is the same, as without virtualization. The names for CPU and BSP stay the same.

The code necessary for the virtualization is shared among the BSPs and CPUs and goes into:

• c/src/lib/libbsp/virt/shared
• cpukit/score/cpu/virt/shared

The Makefiles have to cover these directories.

ARINC 653 API - GSOC 2012

Source code: ​by Wiktor Langowski

The project used syscalls to access POK resources out of RTEMS. To get the code together the RTEMS binary is compiled - what fails. The generated .ralf file is the added to POK by rewriting the partition.bin file and by fixing the size section in the POK binary.

The code uses a hack: By naming a function bsp_start in POK and in RTEMS the function is executed twice. One time in POK-RTEMS and one time in POK. From my point of view that's far away from being a valid approach.