On Mon, Aug 29, 2016 at 11:35:59PM -0400, Zhihong Wang wrote:
> This patch fixes a Windows VM compatibility issue in DPDK 16.07 vhost code,
> which causes the guest to hang once any packets are enqueued when mrg_rxbuf
> is turned on.
This commit log lacks two important pieces: why does the hang happen and
how does your patch fix it.
> How to test?
>
> 1. Start testpmd in the host with a vhost port.
>
> 2. Start a Windows VM image with qemu and connect to the vhost port.
>
> 3. Start io forwarding with tx_first in host testpmd.
>
> For 16.07 code, the Windows VM will hang once any packets are enqueued.
>
> Cc: <stable at dpdk.org>
> Signed-off-by: Zhihong Wang <zhihong.wang at intel.com>
> ---
> lib/librte_vhost/vhost_rxtx.c | 17 ++++++++++++-----
> 1 file changed, 12 insertions(+), 5 deletions(-)
>
> diff --git a/lib/librte_vhost/vhost_rxtx.c b/lib/librte_vhost/vhost_rxtx.c
> index 08a73fd..5806f99 100644
> --- a/lib/librte_vhost/vhost_rxtx.c
> +++ b/lib/librte_vhost/vhost_rxtx.c
> @@ -384,6 +384,8 @@ copy_mbuf_to_desc_mergeable(struct virtio_net *dev,
> struct vhost_virtqueue *vq,
> uint16_t start_idx = vq->last_used_idx;
> uint16_t cur_idx = start_idx;
> uint64_t desc_addr;
> + uint32_t desc_chain_head;
> + uint32_t desc_chain_len;
What's the point of introducing "desc_chain_len"? It has the same value
of desc_offset.
--yliu
