Re: [PATCH v2 3/4] s390x/pv: Introduce a s390_pv_check() helper for runtime

[Cédric Le Goater]

On 1/9/23 10:49, Janosch Frank wrote:
> On 1/9/23 10:27, Cédric Le Goater wrote:
> > On 1/9/23 10:04, Janosch Frank wrote:
> > > On 1/6/23 08:53, Cédric Le Goater wrote:
> > > > From: Cédric Le Goater <clg@redhat.com>
> > > >
> > > > If a secure kernel is started in a non-protected VM, the OS will hang
> > > > during boot without giving a proper error message to the user.
> > >
> > > Most of the time you see nothing in the console because libvirt is too slow. If 
> > > you start the VM in paused mode, attach a console and then resume it, then 
> > > you'll see a nice error message.
> >
> > If you wait long enough, the VM fails to mount / and falls into the dracut
> > initrams.
>
> I have the feeling that we're not talking about the same thing here.>
 > A PV VM always starts out as a non-PV VM and is put into PV mode via two diag308 
subcodes (8 & 10). ALL PV subcodes (8 - 10) are spec exceptions if the host isn't 
enabled for PV.

The corner case this patch is trying to address is for a PV-enabled host,
a secure enabled OS and !PV-enabled QEMU.

Please run this command on a secure disk image :

  qemu-system-s390x -M s390-ccw-virtio -accel kvm -drive 
file=<file>,if=virtio,format=qcow2 -nographic -nodefaults -serial mon:stdio

and tell me what you get.

Thanks,

C.