[PATCH v4 06/16] libqos: add missing virtio-9p feature negotiation

[Stefan Hajnoczi]

VIRTIO Device Initialization requires feature negotiation.  The libqos
virtio-9p driver lacks feature negotiation and is therefore
non-compliant.

libqos tests acknowledge all feature bits advertised by the device,
except VIRTIO_F_BAD_FEATURE (which devices use to detect broken
drivers!) and VIRTIO_RING_F_EVENT_IDX (which is not implemented in
libqos and accepting it would break notifications).

Signed-off-by: Stefan Hajnoczi <address@hidden>
---
 tests/libqos/virtio-9p.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tests/libqos/virtio-9p.c b/tests/libqos/virtio-9p.c
index 8c9efce3e1..77dbfb62ad 100644
--- a/tests/libqos/virtio-9p.c
+++ b/tests/libqos/virtio-9p.c
@@ -32,6 +32,12 @@ static void virtio_9p_cleanup(QVirtio9P *interface)
 
 static void virtio_9p_setup(QVirtio9P *interface)
 {
+    uint64_t features;
+
+    features = qvirtio_get_features(interface->vdev);
+    features &= ~(QVIRTIO_F_BAD_FEATURE | (1ull << VIRTIO_RING_F_EVENT_IDX));
+    qvirtio_set_features(interface->vdev, features);
+
     interface->vq = qvirtqueue_setup(interface->vdev, alloc, 0);
     qvirtio_set_driver_ok(interface->vdev);
 }
-- 
2.21.0