Features/KVM and QEMU merge

Summary
Combine the  and   packages into a single package.

Owner

 * Name: Glauber Costa
 * Email: glommer@redhat.com

Current status

 * Targeted release: Fedora 11
 * Last updated: 2009-03-26
 * Percentage of completion: 100%

Detailed Description
The QEMU package provides a processor and system emulator which enables users to launch guest virtual machines not only under the same hardware platform as the host machine, but also dramatically different hardware platforms. For example, QEMU can be used to run a PPC guest on a x86 host. QEMU dynamically translates the machine code of the guest architecture into the machine code of the host architecture.

KVM provides kernel support for running guests of the same architecture as the host. Guests run directly on the hardware with out any translation needed by the host, allowing much higher levels of performance to be attained. QEMU can now use the KVM kernel support for higher performance virtualization.

Currently, there is both a  package and   package. The  package's source is a fork of the QEMU source, but KVM regularily re-bases to the latest QEMU source and merging of KVM support into the QEMU code base is actively under-way. The medium term plan is for the KVM fork of QEMU to go away.

In anticipation of this, the package maintainers feel it would be a good idea to merge the packages now. This is to be done as follows:


 * 1) The   package is built using the   codebase.
 * 2) The   source package provides a sub-package for each group of target architectures - ,  ,   etc.
 * 3) The   sub-package contains the various user mode emulators.
 * 4) The   package contains BIOS binaries, documentation etc.
 * 5) The   package is obsoleted by.
 * 6) A   meta-package requires all the different target sub-packages.

The  package previously contained binary BIOS images which were copied directly from the upstream release tarball without rebuilding from source. As part of the package merge, this long-standing issue is resolved by splitting those images into their own packages which are built from source -,   and.

Benefit to Fedora
A single package is far more maintainable than multiple packages. Any bug fixes or security errata involves much less work.

This change will have to be made eventually once the merge happens upstream. Doing the package merge now means we reap the benefits earlier.

Scope
No changes are required outside of the changes to the two packages in question.

Comps could be update to pull in  rather than , but either works fine.

The  package needs to be blocked from rawhide.

The  bugzilla product's rawhide version needs removing. Bugs need migrating.

How To Test
Try updating or installing the pre-merge packages using e.g. . Check that updating   results in the   package being installed and that updating   pulls in the various sub-packages.

Aside from the package updating issue, this feature should be tested as any  or   upgrade. Test existing guest virtual machines or install new guests using the package and check they run correctly.

User Experience
No user visible change is expected. Users should be able to run guests in the very same way they did before.

The primary benefit to users is that the  package will no longer lag behind the   package.

Dependencies
There hadn't been a QEMU release in over a year (since 0.9.1). However, upstream recently released 0.10 which helps us to ship an actual released tarball rather than an arbitrary development snapshot.

Since we are building both QEMU and KVM from a  tarball, we need a KVM release based on the QEMU 0.10.x series. This is planned by the upstream KVM maintainer in the short term. In the meantime we're shipping a snapshot of KVM git.

Contingency Plan
No real contingency is required. If the change can't made in time for release, the status quo will remain.

Regressions may be introduced versus the current QEMU 0.9.1 release, but we don't consider that rolling back to a previous release will be an option. QEMU upstream is very active, so we expect any unanticipated regressions would be resolved quickly. This situation isn't really impacted by the merge.

Documentation

 * Package split discussion
 * More discussion
 * QEMU 0.10.0 release annoucement
 * QEMU 0.10.1 release announcement
 * vgabios review request
 * openbios review request
 * bochs-bios review request

Release Notes
Fedora 11 includes a merge of the  and   RPMs. The merging of the two codebases continues upstream, but the Fedora package maintainers have chosen to merge the packages in order reduce the maintainership burden and provide better support.

Comments and Discussion

 * See Talk:Features/KVM and QEMU merge