[libvirt] Device attach / detach problem for passthrough/SR-IOV in libvirt

[Michal Privoznik]

On 27.03.2014 13:53, Mohsen Ghaemi wrote:
> Hi all
>
> I just encountered a problem in libvirt while was trying to attach and
> detach a sr-iov vf to my VM
>
>
> The version of my libvirt is 1.1.1-0ubuntu8.5
>
>
> I tried to attach the device using following xml
>
>
> <interface type='hostdev' managed='yes'>
>
>     <mac address='5c:01:fd:12:34:58'/>
>
>     <source>
>
>         <address type='pci' domain='0x0000' bus='0x04' slot='0x01'
> function='0x1'/>
>
>     </source>
>
> </interface>
>
>
> When i attached device it worked properly and i managed to ping another
> host.
>
>
> virsh # attach-device t5 1.xml
>
> Device attached successfully
>
>
> But when i detached it still i had network traffic in my VM but libvirt
> (virsh) said that
>
>
> virsh # detach-device t5 1.xml
>
> Device detached successfully
>
>
> The next time i tried to attach it libvirt said that
>
>
> virsh # attach-device t5 1.xml
>
> error: Failed to attach device from 1.xml
>
> error: Requested operation is not valid: PCI device 0000:04:01.1 is in
> use by domain t5
>
>
> and when i continue this action after the ‘domain’ i receive some
> strange characters which might come from the memory space (memory
> content) like some addresses, links or some characters
>
>
> I tried it with different VMs and different guest OSs that the same happend.
>
>
> The same action was done with another host running libvirt version
>
>
> Installed: 1.0.2-0ubuntu11.13.04.5~cloud1
>
> Candidate: 1.0.2-0ubuntu11.13.04.5~cloud1

This is probably a bug in libvirt. There's been a rework of hostdev 
plugging and unplugging recently. Can you try the 1.2.3-rc1 and see if 
the problem is gone?

Michal