Re: [Qemu-devel] [Question] why need to start all queues in vhost_net_start

[Jason Wang]

On 2017年11月15日 22:55, Longpeng(Mike) wrote:
> Hi guys,
>
> We got a BUG report from our testers yesterday, the testing scenario was
> migrating a VM (Windows guest, *4 vcpus*, 4GB, vhost-user net: *7 queues*).
>
> We found the cause reason, and we'll report the BUG or send a fix patch
> to upstream if necessary( we haven't test the upstream yet, sorry... ).

Could you explain this a little bit more?

> We want to know why the vhost_net_start() must start *total queues* ( in our
> VM there're 7 queues ) but not *the queues that current used* ( in our VM, guest
> only uses the first 4 queues because it's limited by the number of vcpus) ?
>
> Looking forward to your help, thx :)

Since the codes have been there for years and works well for kernel 
datapath. You should really explain what's wrong.

Thanks