[LTP] [PATCH] Add env variable as workaround for test issues in VMs

[Jan Stancek <jstancek@redhat.com>]

----- Original Message -----
> On Mon, Apr 27, 2020 at 3:31 PM Jan Stancek <jstancek@redhat.com> wrote:
> 
> >
> >
> > ----- Original Message -----
> > > Hi Martin,
> > >
> > > > Timer tests often fail on sleep overrun when LTP is running inside a
> > VM.
> > > > The main cause is usually that the VM doesn't get enough CPU time to
> > wake
> > > > up
> > > > the test process in time.
> > > Cannot we detect presence of "hypervisor" in flags in /proc/cpuinfo?
> > > I though it was quite reliable for detecting VM.
> >
> > We have tst_is_virt().
> >
> 
> I take a rough look and doubt there is a bug in try_systemd_detect_virt().
> Shouldn't strncmp() return zero the 'kvm'/'xen' is found?  I guess they
> wanted:

Yes, that looks like bug.

> 
> --- a/lib/tst_virt.c
> +++ b/lib/tst_virt.c
> @@ -93,10 +93,10 @@ static int try_systemd_detect_virt(void)
>         if (ret)
>                 return 0;
> 
> -       if (strncmp("kvm", virt_type, 3))
> +       if (!strncmp("kvm", virt_type, 3))
>                 return VIRT_KVM;
> 
> -       if (strncmp("xen", virt_type, 3))
> +       if (!strncmp("xen", virt_type, 3))
>                 return VIRT_XEN;
> 
>         return 0;
> 
> Apart from that two(kvm/xen) , we need to detect more virtualization tech
> for ppc/s390 I think.

We could return VIRT_OTHER by default. We don't really need to
differentiate which one it is for purpose of this patch.