Comment 4 for bug 1621042

The discussion is finished, the way to handle this is now defined at https://wiki.ubuntu.com/QemuKVMMigration

I'm prepping a ppa to run my newly created migration test suite against it as well as the qa tests that we discussed.

There is the usual last-minute struggle to get all in, so the ppa is based on the in-queue https://requests.ci-train.ubuntu.com/#/ticket/1931 that moves yakkety to 2.6.1 (which is great, thanks xnox!)

Please note that dev releases and especially wily is special.
It seems broken with the pc_compat_2_3 definition while the rest switched to NULL using the PC_COMPAT_ as well as the "15.04" string in its def we keep it as-is in Xenial being the unifying LTS. Everybody should already be off-wily anyway already.
According to the definition in the linked wiki u,v,w are dropped in yakkety as migrations (like an upgrade) have to go through Xenial.

ppa to test the fixed machine types is at https://launchpad.net/~paelzer/+archive/ubuntu/qemu-machine-type-dev

Test logs before the fix:
http://paste.ubuntu.com/23177826/ - shows the failed way back from T->X->T
http://paste.ubuntu.com/23177831/ - shows the lack of a proper default type

Test logs with the fixes in place:
http://paste.ubuntu.com/23181803/ - shows still the same issue, but following the guidance in bug 1536487 that isn't expected to work
http://paste.ubuntu.com/23181801/ - shows the fix to the expected types while not breaking any else

I asked smb to do his usual tests against that ppa as well to have some extra coverage.

I will go on to add the planned powerpc and s390x parts, drop the 1536487 change and run the suite again.