Re: [PATCH v2 1/2] test: dm: virtio_rng: Update virtio-rng test

[Andre Przywara]

Hi Meet,

On 3/9/26 17:55, Meet Patel wrote:

From: Kavin Gunasekara <kavin.gunasek...@arm.com>

The virtio-rng test to verify effective handling of oversized return
buffers checks that an (undocumented) error is raised, instead of the
real concern, which is the surrounding buffer integrity following a rng
function call.
Update the test to check that the other contents of a buffer remain
unchanged instead of looking for an error code.

thanks for the change, looks good now!

Signed-off-by: Kavin Gunasekara <kavin.gunasek...@arm.com>
Signed-off-by: Meet Patel <meet.pat...@arm.com>

Reviewed-by: Andre Przywara <andre.przyw...@arm.com>

Cheers,
Andre

---
  test/dm/virtio_rng.c | 14 ++++++++++++--
  1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/test/dm/virtio_rng.c b/test/dm/virtio_rng.c
index e404b08484e..5fd56ade586 100644
--- a/test/dm/virtio_rng.c
+++ b/test/dm/virtio_rng.c
@@ -19,12 +19,19 @@ struct virtio_rng_priv {
        struct virtqueue *rng_vq;
  };

+#define BUFFER_SIZE 16

+#define CANARY "CANARYCANARYCANARYCANARY"
+
  /* Test the virtio-rng driver validates the used size */
  static int dm_test_virtio_rng_check_len(struct unit_test_state *uts)
  {
        struct udevice *bus, *dev;
        struct virtio_rng_priv *priv;
-       u8 buffer[16];
+       u8 buffer[BUFFER_SIZE + sizeof(CANARY)];
+
+       /* write known data to buffer */
+       memset(buffer, 0xaa, BUFFER_SIZE);
+       memcpy(buffer + BUFFER_SIZE, CANARY, sizeof(CANARY));

/* check probe success */

        ut_assertok(uclass_first_device_err(UCLASS_VIRTIO, &bus));
@@ -44,7 +51,10 @@ static int dm_test_virtio_rng_check_len(struct 
unit_test_state *uts)
        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)));
+       dm_rng_read(dev, buffer, BUFFER_SIZE);
+
+       /* check for the canary bytes behind the real buffer */
+       ut_asserteq_mem(buffer + BUFFER_SIZE, CANARY, sizeof(CANARY));

return 0;

  }