[PATCH v4 5/5] iotests/iothreads-nbd-export: Skip on s390

[Eric Farman <farman@linux.ibm.com>]

Running this test on s390 causes long python exception tracebacks
at the beginning of the system_reset loop. The problem appears to
be the same one described by commit ad302b21aab6, in that QEMU
will exit on s390 without any kernel or boot disk.

In other tests, this is addressed by adding -no-shutdown to the
command line, and that does create a clean failure instead of a
long line of python exceptions:

  --- /home/farman/git/qemu/tests/qemu-iotests/tests/iothreads-nbd-export.out
  +++ /home/farman/git/qemu/build/scratch/qcow2-file-iothreads-nbd-export/iothreads-nbd-export.out.bad
  @@ -16,4 +16,4 @@
   {"return": {}}
   {"return": {}}
   Checking that it is still alive...
  -{"return": {"running": true, "status": "running"}}
  +{"return": {"running": false, "status": "prelaunch"}}
  Failures: iothreads-nbd-export
  Failed 1 of 1 iotests

...but obviously this isn't still a successful test, since it is
expected that the guest will be still be usable after the reset loop.
So, barring a solution to that, just skip this test on s390.

Signed-off-by: Eric Farman <farman@linux.ibm.com>
---
 tests/qemu-iotests/tests/iothreads-nbd-export | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tests/qemu-iotests/tests/iothreads-nbd-export b/tests/qemu-iotests/tests/iothreads-nbd-export
index 037260729c7..72493ad2279 100755
--- a/tests/qemu-iotests/tests/iothreads-nbd-export
+++ b/tests/qemu-iotests/tests/iothreads-nbd-export
@@ -25,6 +25,11 @@ import iotests
 iotests.script_initialize(supported_fmts=['qcow2'],
                           supported_platforms=['linux'])
 
+# QEMU on s390 will exit without any sort of backing disk,
+# so the reset loop requested by this test will fail.
+if iotests.qemu_default_machine == 's390-ccw-virtio':
+    iotests.notrun('Cannot run test on s390')
+
 with iotests.FilePath('disk1.img') as path, \
      iotests.FilePath('nbd.sock', base_dir=iotests.sock_dir) as nbd_sock, \
      qemu.machine.QEMUMachine(iotests.qemu_prog) as vm:
-- 
2.53.0