Re: [PATCH kvm-unit-tests v2 17/17] x86/unittests: add intel-iommu test

[Peter Xu <peterx@redhat.com>]

On Thu, Nov 10, 2016 at 09:21:41PM +0100, Andrew Jones wrote:
> On Wed, Nov 09, 2016 at 10:10:24AM -0500, Peter Xu wrote:
> > Signed-off-by: Peter Xu <peterx@redhat.com>
> > ---
> >  x86/unittests.cfg | 7 +++++++
> >  1 file changed, 7 insertions(+)
> > 
> > diff --git a/x86/unittests.cfg b/x86/unittests.cfg
> > index 23395c6..5413838 100644
> > --- a/x86/unittests.cfg
> > +++ b/x86/unittests.cfg
> > @@ -217,3 +217,10 @@ extra_params = -cpu kvm64,hv_time,hv_synic,hv_stimer -device hyperv-testdev
> >  file = hyperv_clock.flat
> >  smp = 2
> >  extra_params = -cpu kvm64,hv_time
> > +
> > +[intel_iommu]
> > +file = intel-iommu.flat
> > +arch = x86_64
> > +timeout = 30
> > +smp = 4
> > +extra_params = -M q35,kernel-irqchip=split -device intel-iommu,intremap=on,eim=off -device edu
> > -- 
> > 2.7.4
> >
> 
> I haven't looked up eim=off means, whether or not we want it, but
> otherwise it looks good to me.

When set eim=off, x2apic will be disabled. So basically "eim" bit is
to configure whether we want to support x2apic in the guest, in case
we want to use more than 255 vcpus.

Here:

- if with eim=off, vt-d test will need latest QEMU to run (so if with
  older QEMUs, it'll fail)

- if without eim=off, vt-d test will need latest KVM to run (so if
  with older KVM, it'll fail)

I just chose the 1st one since I guess a latest QEMU is easier to get
and compile than kernel.

Thanks,

-- peterx