Please backport bee980d9e9642e96351fa3ca9077b853ecf62f57(xen/events: Handle VIRQ_TIMER before any other hardirq in event loop.) toearlier kernels v3.8...and so on

[Konrad Rzeszutek Wilk]

 Hey Greg,

I hadn't (by mistake) put the CC: stable@xxxxxxxxxxxxxxx on said patch
(Which is in the Linux kernel).

If possible please back-port said patch to the existing stable trees.
Attached is a version that applies to some of the earlier trees easily.