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Commit 3f8ad847 authored by Stefano Garzarella's avatar Stefano Garzarella Committed by Greg Kroah-Hartman
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vhost/vsock: fix incorrect used length reported to the guest 



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: 433fc58e ("VSOCK: Introduce vhost_vsock.ko")
Cc: stable@vger.kernel.org
Reported-by: default avatarHalil Pasic <pasic@linux.ibm.com>
Suggested-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarStefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/20211122163525.294024-2-sgarzare@redhat.com


Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: default avatarHalil Pasic <pasic@linux.ibm.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent a539070b

drivers/vhost/vsock.c

+1 −1
Original line number Diff line number Diff line
@@ -490,7 +490,7 @@ static void vhost_vsock_handle_tx_kick(struct vhost_work *work) 
			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)));