Dom0 Kernels for Xen

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If you don't know what "dom0" or a "dom0 kernel" is, take look at the detailed explanation here.

This page contains information on Xen dom0 support, if you are looking for information on guest (domU) support see XenDomUSupport.

Contents

Choosing a dom0 kernel

If your Linux distribution includes Xen and dom0 kernel it is recommended to use them. This provides the benefits such as ease of install, good integration with the distribution, support from the distribution, provision of security updates etc.

Xen PV domU kernel versions can be different from dom0 kernel versions. There's no need to upgrade domU kernel when you upgrade Xen hypervisor and/or dom0 kernel. Xen hypervisor is backwards compatible, ie. it supports older domU kernels. If your domU distribution includes a Xen domU kernel, it's usually best to use it and not compile your own domU kernel.

Also please notice that mainline vanilla Linux kernel already supports Xen. Instructions how to configure and build a Linux kernel for Dom0 and DomU support are reported here: Mainline_Linux_Kernel_Configs .

Linux Distributions which have a Xen Dom0 kernel

Distributions Versions
Debian 4.0 (Etch), 5.0 (Lenny), 6.0 (Squeeze)[1]
Fedora 16[1]
OpenSUSE 10.x, 11.x, 12.x
Oracle VM for x86 (OVS) All versions
Redhat Enterprise Linux (RHEL) 5.x
CentOS and other RHEL clones 5.x
SUSE Linux Enterprise Server (SLES) 10.x, 11.x
Ubuntu 11.10[1], 12.04 LTS [1]
Xen Cloud Project (XCP) All versions
XenServer All versions

[1] Please note that this kernel requires Xen >= 4.0.

Xen Dom0 support in BSDs and other Unix systems

This list is currently incomplete. We are in the process of verifying support for other Unixes.

Distributions Versions
NetBSD 5.1 [1], [2]
OpenSolaris 2009.06 [3]
Illumos Incomplete [4]

[1] See NetBSD Xen HowTo for more information
[2] See NetBSD Xen User Guide
[3] OpenSolaris has been discontinued by Oracle, but Xen dom0 support is present in the latest 2009.06 release and later development snapshots before OpenSolaris was discontinued.
[4] Illumos [1] is a fork of OpenSolaris, and Xen dom0 support is present in the Illumos sources, but it's currently unmaintained and untested. Interested developers should be able to make it work again, because it was working earlier in OpenSolaris.

FAQ

Please see XenKernelFeatures for more information about available features in different Xen enabled kernels.

Q: I've seen mentions of 'pv_ops' and 'xenlinux' kernels. Which one should I choose?

Simple answer: pv_ops. Xen 4.0 switched to using Linux pv_ops based dom0 kernel as a default, and it's the most up-to-date and is undergoing active development.

Longer answer: There are two different types of Xen dom0 capable kernels available today:

  • pvops kernels, featuring new rewritten Xen support based on the upstream (kernel.org) Linux pvops framework. This work has been included in upstream kernel.org kernel since Linux 2.6.37.
  • xenlinux kernels based on the "old" patches originally for Linux 2.6.18. These Xenlinux patches won't be integrated to upstream Linux.

However, the pv_ops kernel requires Xen >=4.0. If you desperatly need the Xenlinux patches, SLES/OpenSUSE has been forward-porting the patches.

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