Stephen Rothwell [off-list ref] writes:

Hi all,

Today's linux-next tree does not boot in qemu (with kvm or without).
Here is the (non-kvm) boot log (the kvm one is basically the same):

------------------------------------------------------

...

  Welcome to Open Firmware

  Copyright (c) 2004, 2017 IBM Corporation All rights reserved.
  This program and the accompanying materials are made available
  under the terms of the BSD License available at
  http://www.opensource.org/licenses/bsd-license.php

Booting from memory...
OF stdout device is: /vdevice/vty@71000000
Preparing to boot Linux version 4.19.0-rc7 (sfr@ash) (gcc version 8.2.0 (Debian 8.2.0-4)) #2 SMP Mon Oct 15 18:53:28 AEDT 2018

                                  ^^^^^^^^^^
                                  I assume that's wrong, this is actually linux-next you're booting?

Detected machine type: 0000000000000101
command line: 
Max number of cores passed to firmware: 2048 (NR_CPUS = 2048)
Calling ibm,client-architecture-support... done
memory layout at init:
  memory_limit : 0000000000000000 (16 MB aligned)
  alloc_bottom : 0000000001640000
  alloc_top    : 0000000030000000
  alloc_top_hi : 0000000080000000
  rmo_top      : 0000000030000000
  ram_top      : 0000000080000000
instantiating rtas at 0x000000002fff0000... done
prom_hold_cpus: skipped
copying OF device tree...
Building dt strings...
Building dt structure...
Device tree strings 0x0000000001850000 -> 0x0000000001850a02
Device tree struct  0x0000000001860000 -> 0x0000000001870000
Quiescing Open Firmware ...
Booting Linux via __start() @ 0x0000000000400000 ...
------------------------------------------------------

I have no idea what may have caused this.

If you git Ctrl-a-c you should get the qemu prompt. Then you can run
'info registers' to print the regs and maybe see where it's stuck.

And/or build with EARLY_DEBUG_LPAR to get early console output.

cheers