From: Stefano Garzarella sgarzare@redhat.com
commit 49d8c5ffad07ca014cfae72a1b9b8c52b6ad9cb8 upstream.
The "used length" reported by calling vhost_add_used() must be the number of bytes written by the device (using "in" buffers).
In vhost_vsock_handle_tx_kick() the device only reads the guest buffers (they are all "out" buffers), without writing anything, so we must pass 0 as "used length" to comply virtio spec.
Fixes: 433fc58e6bf2 ("VSOCK: Introduce vhost_vsock.ko") Cc: stable@vger.kernel.org Reported-by: Halil Pasic pasic@linux.ibm.com Suggested-by: Jason Wang jasowang@redhat.com Signed-off-by: Stefano Garzarella sgarzare@redhat.com Link: https://lore.kernel.org/r/20211122163525.294024-2-sgarzare@redhat.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Reviewed-by: Stefan Hajnoczi stefanha@redhat.com Reviewed-by: Halil Pasic pasic@linux.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/vhost/vsock.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/vhost/vsock.c +++ b/drivers/vhost/vsock.c @@ -494,7 +494,7 @@ static void vhost_vsock_handle_tx_kick(s virtio_transport_free_pkt(pkt);
len += sizeof(pkt->hdr); - vhost_add_used(vq, head, len); + vhost_add_used(vq, head, 0); total_len += len; added = true; } while(likely(!vhost_exceeds_weight(vq, ++pkts, total_len)));