1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (c) 2022 Google, Inc.
4  * Written by Andrew Scull <ascull@google.com>
5  */
6 
7 #include <common.h>
8 #include <dm.h>
9 #include <virtio_types.h>
10 #include <virtio.h>
11 #include <virtio_ring.h>
12 #include <dm/device-internal.h>
13 #include <dm/test.h>
14 #include <rng.h>
15 #include <test/test.h>
16 #include <test/ut.h>
17 
18 /* This is a brittle means of getting access to the virtqueue */
19 struct virtio_rng_priv {
20 	struct virtqueue *rng_vq;
21 };
22 
23 /* Test the virtio-rng driver validates the used size */
dm_test_virtio_rng_check_len(struct unit_test_state * uts)24 static int dm_test_virtio_rng_check_len(struct unit_test_state *uts)
25 {
26 	struct udevice *bus, *dev;
27 	struct virtio_rng_priv *priv;
28 	u8 buffer[16];
29 
30 	/* check probe success */
31 	ut_assertok(uclass_first_device_err(UCLASS_VIRTIO, &bus));
32 	ut_assertnonnull(bus);
33 
34 	/* check the child virtio-rng device is bound */
35 	ut_assertok(device_find_first_child(bus, &dev));
36 	ut_assertnonnull(dev);
37 
38 	/* probe the virtio-rng driver */
39 	ut_assertok(device_probe(dev));
40 
41 	/* simulate the device returning the buffer with too much data */
42 	priv = dev_get_priv(dev);
43 	priv->rng_vq->vring.used->idx = 1;
44 	priv->rng_vq->vring.used->ring[0].id = 0;
45 	priv->rng_vq->vring.used->ring[0].len = U32_MAX;
46 
47 	/* check the driver gracefully handles the error */
48 	ut_asserteq(-EIO, dm_rng_read(dev, buffer, sizeof(buffer)));
49 
50 	return 0;
51 }
52 DM_TEST(dm_test_virtio_rng_check_len, UT_TESTF_SCAN_PDATA | UT_TESTF_SCAN_FDT);
53