Archived/Xen Development Projects

Needs Refactor This should be moved to the relevant's a project overview page (or at least be accessible from it). This is basically our "Get Involved" page

Xen Development Projects

This page lists various Xen related development projects that can be picked up by anyone! If you're interesting in hacking Xen this is the place to start! Ready for the challenge?

To work on a project:

• Find a project that looks interesting.
• Send an email to xen-devel mailinglist and let us know you started working on a specific project.
• Post your ideas, questions, RFCs to xen-devel sooner than later so you can get comments and feedback.
• Send patches to xen-devel early for review so you can get feedback and be sure you're going into correct direction.
• Your work should be based on xen-unstable development tree, if it's Xen and/or tools related. After your patch has been merged to xen-unstable it can be backported to stable branches (Xen 4.0, Xen 3.4, etc).
• Your kernel related patches should be based on either upstream kernel.org git tree (latest version), or xen/stable-2.6.32.x tree, depending if it's upstream or xen dom0 related work.

xen-devel mailinglist subscription and archives: http://lists.xensource.com/mailman/listinfo/xen-devel

Before to submit patches, please look at SubmittingXenPatches wiki page.

List of projects

If you have new ideas, suggestions or development plans let us know and we'll update this list!

Domain support

Upstreaming Xen PVSCSI drivers to mainline Linux kernel

Date of insert: 01/08/2012

Technical contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

PVSCSI drivers needs to be upstreamed yet. Necessary operations may include:

• Task 1: Upstream PVSCSI scsifront frontend driver (for domU).
• Task 2: Upstream PVSCSI scsiback backend driver (for dom0).
• Send to various related upstream mailinglists for review, comments.
• Fix any upcoming issues.
• Repeat until merged to upstream Linux kernel git tree.
• http://git.kernel.org/?p=linux/kernel/git/konrad/xen.git;a=shortlog;h=refs/heads/devel/xen-scsi.v1.0
• More info: http://wiki.xen.org/xenwiki/XenPVSCSI

Upstreaming Xen PVUSB drivers to mainline Linux kernel

Date of insert: 01/08/2012

Technical contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

PVUSB drivers needs to be upstreamed yet. Necessary operations may include:

• Upstream PVUSB usbfront frontend driver (for domU).
• Upstream PVUSB usbback backend driver (for dom0).
• Send to various related upstream mailinglists for review, comments.
• Fix any upcoming issues.
• Repeat until merged to upstream Linux kernel git tree.
• http://git.kernel.org/?p=linux/kernel/git/konrad/xen.git;a=shortlog;h=refs/heads/devel/xen-usb.v1.1
• More info: http://wiki.xen.org/xenwiki/XenUSBPassthrough

Blkback improvements

Date of insert: 02/08/2012

Technical contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Blkback requires a number of improvements, some of them being:

• Multiple disks in a guest cause contention in the global pool of pages.
• There is only one ring page and with SSDs nowadays we should make this larger, implementing some multi-page support.
• With multi-page it becomes apparent that the segment size ends up wasting a bit of space on the ring. BSD folks fixed that by negotiating a new parameter to utilize the full size of the ring.
• Add DIF/DIX support [1]
• Further perf evaluation needs to be done to see how it behaves under high load.

Netback overhaul

Date of insert: 02/08/2012

Technical contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Wei Liu posted RFC patches that make the driver be multi-page, multi-event channel and with a page-pool. However not all the issues have been addressed yet, meaning that the patches need to be finished and cleaned up yet. Additively, a zero-copy implementation can be considered. Patch serie and discussions:

• http://lists.xen.org/archives/html/xen-devel/2012-01/msg02561.html
• http://www.spinics.net/lists/linux-nfs/msg22575.html

PAT writecombine fixup

Date of insert: 02/08/2012

Technical contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The writecombine feature (especially for graphic adapters) is turned off due to stability reasons. More specifically, the code involved in page transition from WC to WB gets confused about the PSE bit state in the page, resulting in a set of repeated warnings. For more informations please check:

• Linux git revision 8eaffa67b43e99ae581622c5133e20b0f48bcef1
• http://lists.xen.org/archives/html/xen-devel/2012-06/msg01950.html

ACPI S3-state investigation and fixup

Date of insert: 02/08/2012

Technical contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

During Linux-3.3 release the the S3-state was supposed to work including these patches:

• https://git.kernel.org/?p=linux/kernel/git/konrad/xen.git;a=shortlog;h=refs/heads/devel/acpi-s3.v9

But now it is not working anymore. Scope of the project is understanding the reasons for the issues and fix them.

PUD L3 - big memory - fixup

Date of insert: 02/08/2012

Technical contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Right now guests don't boot with a huge amount of requested kernel memory (tries report failing with certainly 384GB). Scope of the project is understanding the reasons and fix them. This likely involves digging into the toolstack too.

Parallel xenwatch

Date of insert: 01/08/2012

Technical contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Xenwatch is locked with a coarse lock. For a huge number of guests this represents a scalability issue. The need is to rewrite the xenwatch locking in order to support full scalability.

Hypervisor

Microcode uploader implementation

Date of insert: 02/08/2012

Technical contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Intel is working on early implementation where the microcode blob would be appended to the initrd image. The kernel would scan for the appropiate magic constant and load the microcode very early.

The Xen hypervisor can do this similary.

Performace

Performance tools overhaul

Date of insert: 02/08/2012

Technical contact: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Generally, works on the performance tool themselves should be listes separately to the Xen_Profiling:_oprofile_and_perf wiki page.

Xen Cloud Platform (XCP) and XAPI projects

There are separate wiki pages about XCP and XAPI related projects. Make sure you check these out aswell!

• XCP and XAPI development projects: XAPI project suggestions
• XCP short-term roadmap: XCP short term roadmap
• XCP monthly developer meetings: XCP Monthly Meetings
• XAPI developer guide: XAPI Developer Guide

Quick links to changelogs of the various Xen related repositories/trees

Please see XenRepositories wiki page!