libvirt users - Mar 2018 - NIC cannot unplug

Hi:
   I encounter a promble, when I start a domain(only a blank disk, not install
system), I can hotplug NIC, But I cannot hot unplug  NIC.
I consider the domain start from a blank disk, not install system, so the domain
haven't virtio too, I suspect virtio problem.
But I cann't confirm. Can any one tell me?
    Thanks

On 03/05/2018 07:16 AM, llilulu wrote:
> Hi:
>    I encounter a promble, when I start a domain(only a blank disk, not
install system), I can hotplug NIC, But I cannot hot unplug  NIC.
> I consider the domain start from a blank disk, not install system, so the
domain haven't virtio too, I suspect virtio problem.
> But I cann't confirm. Can any one tell me?
>     Thanks
This is expected behaviour. For unplugging a PCI device (or for that
manner some other types too) guest kernel cooperation is required. It's
unsafe to just rip out the device while domain is running. It might
still be using it. This mimics the real physical HW too - usually you
have to press a button and wait for a led to stop glowing/blinking.

Since you don't have any kernel running in your domain, there's nobody
to process the hotunplug request.

Michal