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Date: Thu, 19 Nov 2015 10:18:50 +0800
From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
To: Tetsuya Mukawa <mukawa@igel.co.jp>
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Cc: dev@dpdk.org, ann.zhuangyanying@huawei.com
Subject: Re: [dpdk-dev] [PATCH v4 1/2] vhost: Add callback and private data
 for vhost PMD
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On Thu, Nov 19, 2015 at 11:03:50AM +0900, Tetsuya Mukawa wrote:
> On 2015/11/17 22:29, Yuanhan Liu wrote:
> > On Fri, Nov 13, 2015 at 02:20:30PM +0900, Tetsuya Mukawa wrote:
> >> These variables are needed to be able to manage one of virtio devices
> >> using both vhost library APIs and vhost PMD.
> >> For example, if vhost PMD uses current callback handler and private data
> >> provided by vhost library, A DPDK application that links vhost library
> >> cannot use some of vhost library APIs.
> > Can you be more specific about this?
> >
> > 	--yliu
> 
> How about like below?
> 
> commit log:
> Currently, when virtio device is created and destroyed, vhost library
> will call one of callback handlers.
> The vhost PMD need to use this pair of callback handlers to know which
> virtio devices are connected actually.
> Because we can register only one pair of callbacks to vhost library, if
> the PMD use it, DPDK applications
> cannot have a way to know the events.

Will (and why) the two co-exist at same time?

	--yliu

> This may break legacy DPDK
> applications that uses vhost library.
> To prevent it, this patch adds one more pair of callbacks to vhost
> library especially for the vhost PMD.
> With the patch, legacy applications can use the vhost PMD even if they
> need additional specific handling
> for virtio device creation and destruction.
> For example, legacy application can call
> rte_vhost_enable_guest_notification() in callbacks to change setting.
> 
> Tetsuya