system/utest/machina/virtio_queue.cpp

// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include <machina/virtio.h>
#include <unittest/unittest.h>

#include "virtio_queue_fake.h"

#define QUEUE_SIZE 16

#define VIRTIO_TEST_ID 30

class TestDevice : public VirtioDevice {
public:
    TestDevice()
        : VirtioDevice(VIRTIO_TEST_ID, nullptr, 0, &queue_, 1, 0, UINTPTR_MAX),
          queue_fake_(&queue_) {}

    zx_status_t Init() {
        return queue_fake_.Init(QUEUE_SIZE);
    }

    virtio_queue_t& queue() { return queue_; }
    VirtioQueueFake& queue_fake() { return queue_fake_; }

private:
    virtio_queue_t queue_;
    VirtioQueueFake queue_fake_;
};

static bool test_virtio_queue_overflow(void) {
    BEGIN_TEST;

    TestDevice device;
    ASSERT_EQ(device.Init(), ZX_OK);
    virtio_queue_t& queue = device.queue();
    VirtioQueueFake& queue_fake = device.queue_fake();

    // Setup queu pointers so that the next descriptor will wrap avail->idx
    // to 0.
    queue.avail->idx = UINT16_MAX;
    queue.index = UINT16_MAX;

    uint16_t expected_desc;
    uint32_t data = 0x12345678;
    ASSERT_EQ(
        queue_fake.BuildDescriptor()
            .AppendReadable(&data, sizeof(data))
            .Build(&expected_desc),
        ZX_OK);

    uint16_t desc;
    ASSERT_EQ(virtio_queue_next_avail(&queue, &desc), ZX_OK);
    ASSERT_EQ(desc, expected_desc);
    ASSERT_EQ(queue.avail->idx, 0);
    ASSERT_EQ(queue.index, 0);
    END_TEST;
}

BEGIN_TEST_CASE(virtio_queue)
RUN_TEST(test_virtio_queue_overflow);
END_TEST_CASE(virtio_queue)