When looking into possibilities for testing virtio drivers I was trying to simulate the device's responses in the virtqueue. It required a hack to get access to the virtqueue by accessing the driver's private data and only allows pre-programmed buffer returns but no dynamic responses, data or descriptor modifications.
This is an example of a regression test for the virtio-rng fix in the previous patch.
Signed-off-by: Andrew Scull ascull@google.com --- test/dm/virtio.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+)
diff --git a/test/dm/virtio.c b/test/dm/virtio.c index 7139c31ab5..85791e3f58 100644 --- a/test/dm/virtio.c +++ b/test/dm/virtio.c @@ -12,6 +12,7 @@ #include <dm/root.h> #include <dm/test.h> #include <dm/uclass-internal.h> +#include <rng.h> #include <test/test.h> #include <test/ut.h>
@@ -211,3 +212,38 @@ static int dm_test_virtio_ring(struct unit_test_state *uts) return 0; } DM_TEST(dm_test_virtio_ring, UT_TESTF_SCAN_PDATA | UT_TESTF_SCAN_FDT); + +struct virtio_rng_priv { + struct virtqueue *rng_vq; +}; + +/* Test the virtio-rng driver validates the used size */ +static int dm_test_virtio_rng(struct unit_test_state *uts) +{ + struct udevice *bus, *dev; + struct virtio_rng_priv *priv; + u8 buffer[16]; + + /* check probe success */ + ut_assertok(uclass_first_device(UCLASS_VIRTIO, &bus)); + ut_assertnonnull(bus); + + /* check the child virtio-rng device is bound */ + ut_assertok(device_find_first_child(bus, &dev)); + ut_assertnonnull(dev); + + /* probe the virtio-rng driver */ + ut_assertok(device_probe(dev)); + + /* simulate the device returning the buffer with too much data */ + priv = dev_get_priv(dev); + priv->rng_vq->vring.used->idx = 1; + priv->rng_vq->vring.used->ring[0].id = 0; + priv->rng_vq->vring.used->ring[0].len = U32_MAX; + + /* check the driver gracefully handles the error */ + ut_asserteq(-EIO, dm_rng_read(dev, buffer, sizeof(buffer))); + + return 0; +} +DM_TEST(dm_test_virtio_rng, UT_TESTF_SCAN_PDATA | UT_TESTF_SCAN_FDT);