Re: Xen is a feature

Thomas Gleixner
2009-06-02T23:49:17Z

On Tue, 2 Jun 2009, Steven Rostedt wrote:
> If we were to break an interface with Dom0 for Xen then we would have a bunch
> of people crying foul about us breaking a defined API. One of Thomas's complaints
> (and a valid one) is that once Linux supports an external API it must always
> keep it compatible. This will hamper new development in Linux if the APIs are
> scattered throughout the kernel without much thought.
>
> Now here's a crazy solution. Merge the Xen hypervisor into Linux ;-)

Not that crazy as you might think.

> Give full ownership of Xen to the Linux community. One of your people could be
> a maintainer. This way the API between Dom0 and the hypervisor would be an internal

s/API/ABI/ :)

> one. If you needed to upgrade Dom0, you also must upgrade the hypervisor, but that
> would be fine since the hypervisor would also be in the Kernel proper.
>
> This may not solve all the issues that the x86 maintainers have with the Dom0
> patches, but it may help solve the API one.

In fact it would resolve the ABI problem once and forever as we could
fix hypervisor / dom0 in sync. hypervisor and dom0 need to run in
lock-step anyway if you want to make useful progress aside of
maintaining versioned interfaces which are known to bloat rapidly.

It's not a big deal to set a flag day which says: update hypervisor
and (dom0) kernel in one go.

Thanks,

tglx