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

[Mohsen Ghaemi]

Hi

thanks for your reply

Since I am working on my master thesis and seriously I am running out of
time I decided to downgrade my libvirt from 1.1.1 to 1.0.2 to be able to
continue working on my thesis. Now it works !

But for your information , I already checked the XML file and the interface was
really removed. I checked my host interfaces using ifconfig -a and I found
however I released the device but it is not there and it is not possible to
assign it to other VM so I though it means there is some missed procedure
or some thing like this to unbind pci device ! as i mentioned if I
restarted the libvirt service I was able to attach it again but still it
was not shown in ifconfig -a list. The other point that i noticed was the
number of "irq"s in my logs for MSI/MSI-X while attaching device. I am not
a programmer and I have no clue about interrupts but the point was that in
1.1.1 i cloud see only 2 or 3 "irq" in my logs but now I see 7 or 8 .

regards
Mohsen



On Fri, Mar 28, 2014 at 10:34 AM, Michal Privoznik <mprivozn at redhat.com>wrote:

> 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
>
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