libqos/virtio: return length written into used descriptor

When a 9p request is flushed (ie, cancelled) by the guest, the device
is expected to simply mark the request as used, without sending a 9p
reply (ie, without writing anything into the used buffer).

To be able to test this, we need access to the length written by the
device into the used descriptor. This patch adds a uint32_t * argument
to qvirtqueue_get_buf() and qvirtio_wait_used_elem() for this purpose.

All existing users are updated accordingly.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/tests/libqos/virtio.h b/tests/libqos/virtio.h
index 0a04740adf..69b5b13840 100644
--- a/tests/libqos/virtio.h
+++ b/tests/libqos/virtio.h
@@ -124,6 +124,7 @@ uint8_t qvirtio_wait_status_byte_no_isr(QVirtioDevice *d,
 void qvirtio_wait_used_elem(QVirtioDevice *d,
                             QVirtQueue *vq,
                             uint32_t desc_idx,
+                            uint32_t *len,
                             gint64 timeout_us);
 void qvirtio_wait_config_isr(QVirtioDevice *d, gint64 timeout_us);
 QVirtQueue *qvirtqueue_setup(QVirtioDevice *d,
@@ -140,7 +141,7 @@ uint32_t qvirtqueue_add(QVirtQueue *vq, uint64_t data, uint32_t len, bool write,
                                                                     bool next);
 uint32_t qvirtqueue_add_indirect(QVirtQueue *vq, QVRingIndirectDesc *indirect);
 void qvirtqueue_kick(QVirtioDevice *d, QVirtQueue *vq, uint32_t free_head);
-bool qvirtqueue_get_buf(QVirtQueue *vq, uint32_t *desc_idx);
+bool qvirtqueue_get_buf(QVirtQueue *vq, uint32_t *desc_idx, uint32_t *len);
 
 void qvirtqueue_set_used_event(QVirtQueue *vq, uint16_t idx);