Avoid migration issues with aligned 2MB THB

------- Comment From <email address hidden> 2018-08-20 17:12 EDT-------
Hi, in some environments it was observed that this qemu patch to enable THP made it more likely to hit guest migration issues, however the following kernel patch resolves those migration issues:

https://git.kernel.org/pub/scm/linux/kernel/git/paulus/powerpc.git/commit/?h=kvm-ppc-next&id=c066fafc595eef5ae3c83ae3a8305956b8c3ef15
KVM: PPC: Book3S HV: Use correct pagesize in kvm_unmap_radix()

Once merged upstream, it would be good to include that change as well to avoid potential migration problems. Should I open a new bug for that or is it better to track here?

Note Paelzer: I have not seen related migration issues myself, but it seems reasonable and confirmed by IBM.