Kernel 3.14 Final was just released today. It would seem likely that Ubuntu 14.04 LTS will be released with this version. Of course VirtualBox requires a very simple module recompile to work - and virt-manager will work. So there is a potential problem for VMware because of the LTS question. I don't use Fedora except in a VM but I'm pretty sure that will be the case for this distro as its a rolling release.
Naturally I expect no answer from VMware concerning kernel support. Patches may be OK for individuals or small companies but for larger companies - who knows?
Perhaps you should be asking Linux developers the question, "Why isn't the 3.14 Linux kernel backwards compatible with existing 3.x drivers?"
Most software only breaks compatibility at major releases. Only Linux seems capable of breaking compatibility with just about every minor release.
Good question. However I installed VirtualBox on Ubuntu 14.04 using the version 4.36 provided by the Ubuntu repos. I didn't even need to recompile the modules as the kernel went from 13.12 to 3.12. to 3.14 - Worked without a hitch no incompatibiltitys with updated drivers. Same with libvirt. I'm guessing (and of course this is only a guess) that incompatibilities arise because the VMware source is closed. Microsoft OS's upgrades also break Windows drivers with programs other the WS. When I use the versions of VB provided by Oracle (now 4.3.10) I only need run /etc/init.d/vboxdrv setup to recompile the modules for the new kernel version. What galls me sometimes is that the marketing side of th company wil r example, the WS 10 is compatible with all recent kernels (think they withdrew this claim however). Naturally you guys are not responsible Since VMware (as well as Microsoft) have contributed some code to the kernel it is somewhat confusing. The patches developed for kernel 3.13 work fine with the kernel optimized for Ubuntu so I'll stick with 3.13 since I won't have to keep two items in GRUB.
I haven't had time to try Pavlinux's pataches for 3.14. If somebody says they have gotten it to work (beside the developer) I will make an effort to create them from the diff files. Does seem that code in the module sources besides filter.c needs reworking for that .
@jmattson, linux is wicked awesome for bringing in so much code that breaking compatibility with every major release is practically unavoidable. About doing that with every minor release, I have no idea what you're talking about.
Now that they're even starting to accept the VMware modules upstream, it won't really matter that much even though the development may seem too rapid for other folks.