Re: [Qemu-devel] Re: [Xen-devel] [PATCH 0/7] merge some xen bits into qemu

[Anthony Liguori <anthony@codemonkey.ws>]

Hi Ian,

Ian Jackson wrote:
> People unfamiliar with the context should note that Gerd's submission
> is NOT `merging some Xen bits into qemu'.  The code that Gerd is
> submitting is VERY SUBSTANTIALLY DIFFERENT from the code which exists
> in the Xen version of qemu.
>   

Here's how I see things:

Gerd has implemented an alternative userspace for Xen PV guests all 
based on QEMU.  The code is well structured and integrates into QEMU in 
a nice way.  On technical merits alone, I have a hard time not merging 
it into QEMU.

It's not Xend/blktap and while you all haven't been clear on this point, 
I don't think there's any chance that Xen.org or whatever your formal 
body is will ever bless this approach.

Naturally, this alternative userspace fits well for something like 
Xenner which emulates a Xen PV guest in QEMU or KVM.  This is also 
something that I don't think Xen.org will ever bless.

Gerd has posted this series on xen-devel and there hasn't been any real 
substantial feedback.  He's been pretty patient about it.  I think this 
is somewhat misleading because I don't think there's any chance these 
patches will ever be pulled into xen-unstable.  And BTW, any code that 
has a remote chance of being merged into QEMU eventually should be 
cross-posted on qemu-devel.  Developing on xen-devel and then dropping a 
big pile of crud onto qemu-devel is not a viable development style.  The 
same is true for other QEMU forks like KVM.

All this said, I don't think we should just pull in Gerd's patches as-is 
and forget about the Xen.org blessing.  I want to encourage all of the 
work that's being done in xen-unstable to be merged back into QEMU 
upstream and that would certainly discourage this process.

So at this point, I think we need some clarification.  Ian, if you have 
no intention of ever merging these patches in any form, I think you 
should be clear about that.

Gerd, I think you need to restructure your patches to do two things.  
The first is to never mention the name "Xen" as it's trademarked and 
owned by Xen.org.  There should be no confusion that this functionality 
is in anyway endorsed or supported by Xen.org.  The second thing is that 
whatever you do has to get easily out of the way of anything that's in 
xen-unstable.  It should cause no merging pain to Ian.  It should also 
be relatively easy to exclude from the build.  If you just keep 
everything as separate files as you are, then it's just a matter of not 
compiling them in.

I hope this will make everyone happy and we can stop posting this series 
and arguing about it.  Does anyone have any objections to this?

Regards,

Anthony Liguori