diff --git a/hw/s390x/virtio-ccw.c b/hw/s390x/virtio-ccw.c index 4582e94ae7..06c0605681 100644 --- a/hw/s390x/virtio-ccw.c +++ b/hw/s390x/virtio-ccw.c @@ -327,13 +327,20 @@ static int virtio_ccw_cb(SubchDev *sch, CCW1 ccw) ccw.cmd_code); check_len = !((ccw.flags & CCW_FLAG_SLI) && !(ccw.flags & CCW_FLAG_DC)); - if (dev->force_revision_1 && dev->revision < 0 && - ccw.cmd_code != CCW_CMD_SET_VIRTIO_REV) { - /* - * virtio-1 drivers must start with negotiating to a revision >= 1, - * so post a command reject for all other commands - */ - return -ENOSYS; + if (dev->revision < 0 && ccw.cmd_code != CCW_CMD_SET_VIRTIO_REV) { + if (dev->force_revision_1) { + /* + * virtio-1 drivers must start with negotiating to a revision >= 1, + * so post a command reject for all other commands + */ + return -ENOSYS; + } else { + /* + * If the driver issues any command that is not SET_VIRTIO_REV, + * we'll have to operate the device in legacy mode. + */ + dev->revision = 0; + } } /* Look at the command. */