From mboxrd@z Thu Jan  1 00:00:00 1970
From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
Subject: Re: [dpdk-stable] [PATCH v6 1/6] vhost: fix windows vm
	hang
Date: Thu, 13 Oct 2016 14:18:51 +0800
Message-ID: <20161013061851.GZ10323@yliu-dev.sh.intel.com>
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On Mon, Sep 19, 2016 at 10:00:12PM -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 by setting the right id and len in the used ring.
> 
> As defined in virtio spec 0.95 and 1.0, in each used ring element, id means
> index of start of used descriptor chain, and len means total length of the
> descriptor chain which was written to. While in 16.07 code, index of the
> last descriptor is assigned to id, and the length of the last descriptor is
> assigned to len.
> 
> 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@dpdk.org>
> Signed-off-by: Zhihong Wang <zhihong.wang@intel.com>

Applied to dpdk-next-virtio (this patch only).

Thanks.

	--yliu