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From: "Tan, Jianfeng" <jianfeng.tan@intel.com>
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Date: Fri, 13 May 2016 10:00:55 +0800
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Subject: Re: [dpdk-dev] [PATCH v4 6/8] virtio-user: add new virtual pci
	driver for virtio
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Hi Michael,

On 5/13/2016 1:02 AM, Michael S. Tsirkin wrote:
> On Thu, May 12, 2016 at 03:08:05PM +0800, Tan, Jianfeng wrote:
>> (2) It's more aligned to previous logic to hide the detail to differentiate
>> modern/legacy device.
> Why is there a need to support legacy interfaces at all?  It's a container
> so if it's in use one can be reasonably sure you have a new kernel.
>

No, there's no need. The added device, virtio-user, is parallel to 
legacy and modern device. But there's a feature bit inside vhost user 
protocol for vhost user to decide the length of header, current 
implementation by default set this feature bit.

Thanks,
Jianfeng