Original virtio_test only use add one descriptor for each io event, thus code of descriptor chain and indirection have not been tested(one descriptor will not use indirect feature even indirect feature has been specified). In fact it would have not been possible for vhost_test to access to the indirect descriptor table, because it's impossible for virtio_ring.c to allocate it.

This series using descriptor chain and enable indirection feature. And through gcov we find the code coverage has been improved(not high for virtio_ring.c because virtio_test only test split virtqueue):

+------------+-------------+-------------+
|            |virtio_test.c|virtio_ring.c|
+------------+-------------+-------------+
| original   |   72.32%    |   24.71%    |
+------------+-------------+-------------+
| current    |    75%      |   28.05%    |
+------------+-------------+-------------+

Guo Zhi (4):
  virtio_test: kick vhost for a batch of descriptors
  virtio_test: move magic number in code as defined constant
  virtio_test: use random length scatterlists to test descriptor chain
  virtio_test: enable indirection feature

 tools/virtio/virtio_test.c | 86 ++++++++++++++++++++++++++++----------
 1 file changed, 64 insertions(+), 22 deletions(-)

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2.17.1