tests/virtio-blk-test: set up virtqueue after feature negotiation

VIRTIO Device Initialization requires that feature negotiation has
completed before virtqueues are set up.  This makes sense because the
driver must know whether it is operating in Legacy or VIRTIO 1.0 mode
before it can access vring fields with the correct endianness.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20191023100425.12168-6-stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

tests/virtio-blk-test.c

@@ -113,8 +113,8 @@ static uint64_t virtio_blk_request(QGuestAllocator *alloc, QVirtioDevice *d,
     return addr;
 }
 
-static void test_basic(QVirtioDevice *dev, QGuestAllocator *alloc,
-                       QVirtQueue *vq)
+/* Returns the request virtqueue so the caller can perform further tests */
+static QVirtQueue *test_basic(QVirtioDevice *dev, QGuestAllocator *alloc)
 {
     QVirtioBlkReq req;
     uint64_t req_addr;
@@ -124,6 +124,7 @@ static void test_basic(QVirtioDevice *dev, QGuestAllocator *alloc,
     uint8_t status;
     char *data;
     QTestState *qts = global_qtest;
+    QVirtQueue *vq;
 
     features = qvirtio_get_features(dev);
     features = features & ~(QVIRTIO_F_BAD_FEATURE |
@@ -135,6 +136,8 @@ static void test_basic(QVirtioDevice *dev, QGuestAllocator *alloc,
     capacity = qvirtio_config_readq(dev, 0);
     g_assert_cmpint(capacity, ==, TEST_IMAGE_SIZE / 512);
 
+    vq = qvirtqueue_setup(dev, alloc, 0);
+
     qvirtio_set_driver_ok(dev);
 
     /* Write and read with 3 descriptor layout */
@@ -331,14 +334,16 @@ static void test_basic(QVirtioDevice *dev, QGuestAllocator *alloc,
 
         guest_free(alloc, req_addr);
     }
+
+    return vq;
 }
 
 static void basic(void *obj, void *data, QGuestAllocator *t_alloc)
 {
     QVirtioBlk *blk_if = obj;
     QVirtQueue *vq;
-    vq = qvirtqueue_setup(blk_if->vdev, t_alloc, 0);
-    test_basic(blk_if->vdev, t_alloc, vq);
+
+    vq = test_basic(blk_if->vdev, t_alloc);
     qvirtqueue_cleanup(blk_if->vdev->bus, vq, t_alloc);
 
 }
@@ -746,9 +751,7 @@ static void resize(void *obj, void *data, QGuestAllocator *t_alloc)
     QVirtQueue *vq;
     QTestState *qts = global_qtest;
 
-    vq = qvirtqueue_setup(dev, t_alloc, 0);
-
-    test_basic(dev, t_alloc, vq);
+    vq = test_basic(dev, t_alloc);
 
     qmp_discard_response("{ 'execute': 'block_resize', "
                          " 'arguments': { 'device': 'drive0', "