[Lucid SRU] Prepare virtual to replace ec2

[Stefan Bader]

On 09.05.2013 12:42, Andy Whitcroft wrote:
> On Wed, May 08, 2013 at 06:21:46PM +0200, Stefan Bader wrote:
> 
>> Mostly "less surprise". It is hard to put it into specific benefits. To some
>> degree the master kernel uses more up to date interfaces. I recall a request
>> long ago about refreshing the interrupt handling. This was never completely done
>> because the ec2 codebase is so much different. You may remember that I tried to
>> re-fresh the ec2 patchset which was an even more frightening result.
>> This way the Lucid ec2 user would also get a tickless kernel and hv assisted
>> spinlocks. And if there are issues we will have more luck in picking fixes from
>> upstream. Not to mention that we should have less of a chance to miss a security
>> related change either because it is in the copies of x86 files or because it is
>> made in upstream xen drivers.
> 
> IIRC security were keen to see the split go as the security status of it
> is much harder to be sure of.

That is the main reason for this. But it isn't something that I would claim to
be a benefit for the average user. Which is, what I understood, what Tim was
asking about.

One thing to clarify, Tim when you said big change, you meant moving from ec2
patch to normal kernel and not the size of the pull request, right? Because that
is only modifying Xen specific options and cause some Xen drivers to be
built-in. Nothing of that should affect bare-metal. And on its own does not
change anything beyond preparing the server and generic-pae (and by that
virtual) to be an alternative for ec2. Unless the meta file is changed. And we
can keep the ec2 branch up to date in parallel for a while and should things go
wrong we have a quick fallback.

Oh, maybe one argument for the change is that when people create their own Xen
Lucid installs they usually end up with one of the kernels based on master. This
can currently cause a bit of confusion when then getting a different Xen
experience as when using the cloud images.

-Stefan
> 
> -apw
> 


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