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

[Peter Xu <peterx@redhat.com>]

On Fri, Nov 04, 2016 at 06:46:23PM +0100, Andrew Jones wrote:
> On Wed, Oct 26, 2016 at 03:47:20PM +0800, Peter Xu wrote:
> > I used pc-q35-2.7 instead of default q35 since I'd better make sure both
> > QEMU 2.7/2.8 can run the test, which is to at least satisfy the
> > following matrix:
> > 
> >   |----------+-----------+------------|
> >   | versions | KVM < 4.7 | KVM >= 4.7 |
> >   |----------+-----------+------------|
> >   | QEMU 2.7 |           |            |
> >   | QEMU 2.8 |           |            |
> >   |----------+-----------+------------|
> > 
> > If using default q35, QEMU2.8+KVM<4.7 will fail to run.
> > 
> > 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 f760d8f..d59cf68 100644
> > --- a/x86/unittests.cfg
> > +++ b/x86/unittests.cfg
> > @@ -206,3 +206,10 @@ 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 pc-q35-2.7,kernel-irqchip=split -device intel-iommu,intremap=on -device edu
> > -- 
> > 2.7.4
> > 
> 
> Hmm, this is the first we've worried about this in kvm-unit-tests (And
> I'm not sure we should start). Usually we just want the tests to work
> with latest KVM and latest QEMU, or to graceful fail with
> report_xfail/skip/abort when it can determine that it's missing something
> it needs.

For this test, the latest command line should be:

  -M q35,kernel-irqchip=split -device intel-iommu,intremap=on -device edu

However it will fail if kernel version <4.7 (without x2apic supported
KVM). No chance for a report_skip().

I can use eim=off to avoid that check, however, if with "eim=off", we have:

  -M q35,kernel-irqchip=split -device intel-iommu,intremap=on,eim=off -device edu

It requires QEMU to be latest (>2.8). Otherwise QEMU will report "eim
property not found" and we lost chance to report as well.

So, I just chose to use pc-q35-2.7 here. Not sure whether this is a
good idea.

-- peterx