kvm tools: support 9p flush command

While we process 9p requests serially, so there's no point for implementing
flush, we still need to answer it to prevent guest kernel from hanging waiting
for it.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Signed-off-by: Pekka Enberg <penberg@kernel.org>

diff --git a/tools/kvm/virtio/9p.c b/tools/kvm/virtio/9p.c
index b4341b91e9745a5dfa4d313c197649c73446e1e2..830fc5026d8641144af261fe862371f6f9aa466c 100644 (file)
--- a/tools/kvm/virtio/9p.c
+++ b/tools/kvm/virtio/9p.c
@@ -1071,6 +1071,19 @@ err_out:
        return;
 }
 
+static void virtio_p9_flush(struct p9_dev *p9dev,
+                               struct p9_pdu *pdu, u32 *outlen)
+{
+       u16 tag, oldtag;
+
+       virtio_p9_pdu_readf(pdu, "ww", &tag, &oldtag);
+       virtio_p9_pdu_writef(pdu, "w", tag);
+       *outlen = pdu->write_offset;
+       virtio_p9_set_reply_header(pdu, *outlen);
+
+       return;
+}
+
 static void virtio_p9_eopnotsupp(struct p9_dev *p9dev,
                                 struct p9_pdu *pdu, u32 *outlen)
 {
@@ -1105,7 +1118,7 @@ static p9_handler *virtio_9p_dotl_handler [] = {
        [P9_TCLUNK]       = virtio_p9_clunk,
        [P9_TFSYNC]       = virtio_p9_fsync,
        [P9_TREAD]        = virtio_p9_read,
-       [P9_TFLUSH]       = virtio_p9_eopnotsupp,
+       [P9_TFLUSH]       = virtio_p9_flush,
        [P9_TLINK]        = virtio_p9_link,
        [P9_TSYMLINK]     = virtio_p9_symlink,
        [P9_TLCREATE]     = virtio_p9_create,