From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tetsuya Mukawa <mukawa@igel.co.jp>
Subject: Re: [PATCH v4 1/2] vhost: Add callback and private data
 for vhost PMD
Date: Thu, 19 Nov 2015 12:13:38 +0900
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On 2015/11/19 11:18, Yuanhan Liu wrote:
> 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?

Yes it is. Sure, I will describe below in commit log.

Because we cannot map some of vhost library APIs to ethdev APIs, in some
cases, we still
need to use vhost library APIs for a port created by the vhost PMD. One
of example is
rte_vhost_enable_guest_notification().

Thanks,
Tetsuya


>
> 	--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