Merge tag 'for-linus-4.13b-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip

Pull xen fixes from Juergen Gross:
 "Some fixes and cleanups for running under Xen"

* tag 'for-linus-4.13b-rc2-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/xen/tip:
  xen/balloon: don't online new memory initially
  xen/x86: fix cpu hotplug
  xen/grant-table: log the lack of grants
  xen/x86: Don't BUG on CPU0 offlining