Re: [Qemu-devel] [PATCH 1/2] vhost: enable any layout feature

[Michael S. Tsirkin]

On Mon, Sep 26, 2016 at 11:01:58AM -0700, Stephen Hemminger wrote:
> I assume that if using Version 1 that the bit will be ignored
> 

Therein lies a problem. If dpdk tweaks flags, updating it
will break guest migration.

One way is to require that users specify all flags fully when
creating the virtio net device.  QEMU could verify that all required
flags are set, and fail init if not.

This has other advantages, e.g. it adds ability to
init device without waiting for dpdk to connect.

However, enabling each new feature would now require
management work. How about dpdk ships the list
of supported features instead?
Management tools could read them on source and destination
and select features supported on both sides.

-- 
MST