libqos: add missing virtio-9p feature negotiation

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 <stefanha@redhat.com>
Message-Id: <20191023100425.12168-7-stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Thomas Huth" <thuth@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2019-10-23 11:04:15 +01:00 committed by Michael S. Tsirkin
parent 36d27d2120
commit c5bd6d02e6

View File

@ -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);
}