Description of problem:
An attempt to start a VM on an s390x host fails with the following error:

[root@rtt8 ~]# virsh start fedora23 --console
error: Failed to start domain fedora23
error: internal error: early end of file from monitor: possible problem:
ioctl(KVM_CREATE_VM) failed: 22 Invalid argument
Host kernel setup problem detected. Please verify:
- for kernels supporting the switch_amode or user_mode parameters, whether
  user space is running in primary address space
- for kernels supporting the vm.allocate_pgste sysctl, whether it is enabled
failed to initialize KVM: Invalid argument

"sysctl vm.allocate_pgste=1" fixes this issue, but this should be set automatically, not by the user.


Version-Release number of selected component (if applicable):
kernel-4.2.6-300.fc23.s390x
libvirt-1.2.18.1-2.fc23.s390x
qemu-kvm-2.4.1-1.fc23.s390x

How reproducible:
always

Steps to Reproduce:
1. prepare an XML definition of a virtual machine (will be attached)
2. 
dnf install libvirt qemu-kvm
systemctl start libvirtd
cd /var/lib/libvirt/images/
qemu-img create -f qcow2 fedora23.img 6G
wget http://dl.fedoraproject.org/pub/fedora-secondary/releases/23/Server/s390x/os/images/kernel.img
wget http://dl.fedoraproject.org/pub/fedora-secondary/releases/23/Server/s390x/os/images/initrd.img
modprobe kvm
virsh define fedora23_install.xml
virsh start fedora23 --console

Actual results:
error: Failed to start domain fedora23
error: internal error: early end of file from monitor: possible problem:
ioctl(KVM_CREATE_VM) failed: 22 Invalid argument

Expected results:
VM starts