Subject: Re: KVM guests freeze under upstream kernel

From: [email-masked]
Date: Thu, 20 Jul 2017 00:02:23 -0300

On Thu, Jul 20, 2017 at 09:42:50AM +1000, Benjamin Herrenschmidt wrote:
> On Wed, 2017-07-19 at 16:46 -0300, [email-masked] wrote:
> > Hello!
> > 
> > We're not able to boot any KVM guest using upstream kernel (cb8c65ccff7f77d0285f1b126c72d37b2572c865 - 4.13.0-rc1+).
> > After reaching the SLOF initial counting, the guest simply freezes:
> 
> Can you send our .config ?

Sure,

Answering Michael as well:

It's a P9 with RHEL kernel 4.11.0-10.el7a.ppc64le installed. The problem
was noticed with kernel > 4.13 (I'm currently running 4.13.0-rc1+).

QEMU is https://github.com/dgibson/qemu (ppc-for-2.10) but I gave the
default packaged Qemu a try.

For the guest, I tried both a vanilla Ubuntu 17.04 and the host kernel.
But they had never a chance to run since the freezing happened in SLOF.

Note that using the 4.11.0-10.el7a.ppc64le kernel it works fine
(for any of these Qemu/Guest setup). With 4.13.0-rc1 I have it run after
reverting that referred commit.

Thanks!

(config attached)
--------------------------