On Thu, Jul 13, 2017 at 11:08 AM, Michal Skrivanek <mskrivan@redhat.com> wrote:
> On 12 Jul 2017, at 16:30, Gianluca Cecchi <gianluca.cecchi@gmail.com> wrote:
>
> In the mean time I have verified that the problem is with
>
> emulatedMachine=pc-i440fx-rhel7.3.0

Might be. The fact that it works with 7.2 in esxi nested environment
is nice, but definitely not supported.
Use lower-than-broadwell CPU - that might help. Instead of qemu64
which is emulated...but if if works fast enough and reliably for you
then it's fine


The qemu64 is not a problem actually, because if I set cpu Broadwell and machine type pc-i440fx-rhel7.2.0 things go well.
Also, on an older physical hw with Westmere CPUs where I have oVirt 4.1 too, the VMs start with emulatedMachine=pc-i440fx-rhel7.3.0, so this parameter doesn't depend on cpu itself.

I think emulatedMachine is comparable to vSphere Virtual HW instead, correct?
And that this functionality is provided actually by qemu-kvm-ev (and perhaps in junction with seabios?).
If I run 

rpm -q --changelog qemu-kvm-ev I see in fact

...
* Mon Jun 06 2016 Miroslav Rezanina <mrezanin@redhat.com> - rhev-2.6.0-5.el7
...
- kvm-pc-New-default-pc-i440fx-rhel7.3.0-machine-type.patch [bz#1305121]
...

So it means that at a certain point, the default machine type used by qemu-kvm-ev has become 7.3 and this generates problems in my specific lab environment now (not searching "official" support for it.. ;-).
For the other ordinary L2 VMs definedinside this oVirt nested environment, I can set in System --> Advanced Parameters --> Custom Emulated Machine the value pc-i440fx-rhel7.2.0 and I'm ok and they are able to start.
The problem still remains for the engine vm itself, where I cannot manually set it.
Possibly is there a qemu-kvm-ev overall system configuration where I can tell to force emulated machine type to pc-i440fx-rhel7.2.0 (without downgrading qemu-kvm-ev)?

Otherwise I know that when I have to poweroff/restart the engine vm I have to manually start it in 7.2 mode, as I'm testing right now.

Hope I have clarified better...

Gianluca