[ovirt-users] Hyper-V in a guest

[Richard W.M. Jones]

On Sat, Sep 26, 2015 at 11:15:49PM -0700, Alan Murrell wrote:
> As a followup to my last e-mail, I grepped the
> '/var/log/vdsm/vdsm.log' file for the name of my VM so I could see
> what CPU options (and options in general) were being passed, and I
> definitely see that "hyperVenable" is being set to "true"

I don't think hyperVenable is anything to do with this.

> I could try a full reboot of my host, in case the "kvm_intel" module
> didn't get properly (re-)loaded with the "nested" option....?

You can check if the nested option is enabled by doing:

$ cat /sys/module/kvm*/parameters/nested

The output will be either '1' or 'Y' if nested virt is enabled.

A reboot of the host may help.  I don't think it's possible to change
the nested flag without reloading the module, and that is impossible
without stopping all KVM guests.

BTW nested on Intel and AMD works completely differently (and on Intel
at least details depend on the precise CPU too).  It was definitely
broken on Intel with the RHEL 7.0 kernel, but I think Paolo fixed the
major bugs in 7.1.  On all hardware, nested can be pot luck - it may
cause host crashes.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
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