Re: [PATCH 1/2] vhost/vsock: fix incorrect used length reported to the guest

[Halil Pasic]

On Mon, 22 Nov 2021 17:35:24 +0100
Stefano Garzarella  wrote:

> 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: sta...@vger.kernel.org
> Reported-by: Halil Pasic 
> Suggested-by: Jason Wang 
> Signed-off-by: Stefano Garzarella 

Reviewed-by: Halil Pasic 

> ---
>  drivers/vhost/vsock.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
> index 938aefbc75ec..4e3b95af7ee4 100644
> --- a/drivers/vhost/vsock.c
> +++ b/drivers/vhost/vsock.c
> @@ -554,7 +554,7 @@ 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)));

___
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization

[PATCH 1/2] vhost/vsock: fix incorrect used length reported to the guest

[Stefano Garzarella]

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: sta...@vger.kernel.org
Reported-by: Halil Pasic 
Suggested-by: Jason Wang 
Signed-off-by: Stefano Garzarella 
---
 drivers/vhost/vsock.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
index 938aefbc75ec..4e3b95af7ee4 100644
--- a/drivers/vhost/vsock.c
+++ b/drivers/vhost/vsock.c
@@ -554,7 +554,7 @@ 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)));
-- 
2.31.1

___
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization