hw/virtio/virtio-nsm: Respond with correct length

When we return a response packet from NSM, we need to indicate its
length according to the content of the response. Prior to this patch, we
returned the length of the source buffer, which may confuse guest code
that relies on the response size.

Fix it by returning the response payload size instead.

Fixes: bb154e3e0cc715 ("device/virtio-nsm: Support for Nitro Secure Module device")
Reported-by: Vikrant Garg <vikrant1garg@gmail.com>
Signed-off-by: Alexander Graf <graf@amazon.com>
Message-Id: <20250213114541.67515-1-graf@amazon.com>
Reviewed-by: Dorjoy Chowdhury <dorjoychy111@gmail.com>
Fixes: bb154e3e0cc715 (&quot;device/virtio-nsm: Support for Nitro Secure Module device&quot;)<br>
Reported-by: Vikrant Garg <vikrant1garg@gmail.com>
Signed-off-by: Alexander Graf <graf@amazon.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Vikrant Garg <vikrant1garg@gmail.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/virtio/virtio-nsm.c b/hw/virtio/virtio-nsm.c
index 098e1aeac6e249f0ee42046426ca3ecf9ea6a59a..b22aa74e34d228bbacd5db2fc8eb6e2d9bcb9960 100644 (file)
--- a/hw/virtio/virtio-nsm.c
+++ b/hw/virtio/virtio-nsm.c
@@ -1596,7 +1596,7 @@ static void handle_input(VirtIODevice *vdev, VirtQueue *vq)
     g_free(req.iov_base);
     g_free(res.iov_base);
     virtqueue_push(vq, out_elem, 0);
-    virtqueue_push(vq, in_elem, in_elem->in_sg->iov_len);
+    virtqueue_push(vq, in_elem, sz);
     virtio_notify(vdev, vq);
     return;