Move to qemu vanilla

[chavafg]

In recent days we have talk about moving our default hypervisor from the 2.11 qemu-lite to a newer version of the qemu, which could be qemu vanilla 3.1.0 or 4.0.0 (which is still in rc).

Opening this issue to discuss further.

[chavafg]

btw, I have already took the task to test qemu 3.1.0 locally and all QA tests seem pretty stable.

[jcvenegas]

+1
The benefits related with this:

• Updated qemu: Bugfixes, security issues fixed from upstream.
• Better testing for multiples architectures
• New features: Use memory ballooning when memory is reduced #790 depends on this to provide a good support for VFIO cases.

Some items to fix to consider this complete are:

• Static binaires provide the latest qemu version.
• Packaging already provides qemu-vanilla package but need to deprecate qemu-lite and move qemu-vanilla as default
• Deprecate qemu-lite
• Move CI to test qemu vanilla
• @bergwolf talk about a minimal qemu version for people dont want to move qemu in a long time. (probably and aditional job to test kata with this defined qemu would be a good option)
• Performance as we are moving from qemu-lite we may seen some regressions @grahamwhaley

[jcvenegas]

@sameo @sboeuf nemu following stable qemu releases? If yes would be great both qemu vanilla and nemu are based on the same qemu version to reduce differences that qemu and nemu for easier testing.

[sboeuf]

@jcvenegas yes for now NEMU relies on 3.1, but there is some ongoing work to rebase NEMU on top of 4.0.

[grahamwhaley]

@jcvenegas et. al. I opened a similar issue and did some metrics measures last month ;-) - over at #1253
Reference that for the metrics impacts, but I think let this Issue be the place for the current discussion.

[mcastelino]

@jcvenegas can you have a list of out of tree QEMU patches we carry today?

[mcastelino]

Assess the need for porting qemu-lite patches
kata-containers/qemu#6

[mcastelino]

WIP: DNM: qemu: update qemu vanilla version #1407
#1407

[mcastelino]

Metrics Data from @grahamwhaley
#1253 (comment)