[vfio-users] passthrough usb controler pci-e card ?

[thibaut noah]

Update note, i found what prevent my card from running, basically i need to
reboot without anything plug into the card and then i can unbind and rebind
the card, what that strange behaviour?

2016-01-19 11:35 GMT+01:00 thibaut noah <thibaut.noah at gmail.com>:

> Bumping this, running virsh nodedev-detach pci_0000_xx_yy_z'  (with
> proper numbers) and/or having managed=yes in the xml file changes nothing
> (actually i had this already), ovmf still hangs waiting for i have no idea
> what.
> Cannot run by unbinding the device through script either, seems that i was
> lucky, or maybe i did something that i forgot.
> Tried to add nodedev-detach to modprobe but it seems that i did not do it
> in the proper way so it wasn't working
>
> 2016-01-16 11:30 GMT+01:00 thibaut noah <thibaut.noah at gmail.com>:
>
>> Didn't know libvirt was capable of unbinding devices on its own, good to
>> know, i'm gonna try this and if i manage to make it work i don't have any
>> reason to bother myself more with this. (note that i don't use virt-manager
>> since you advise me to use libvirt directly)
>> Though the usb card will only be use by the vm, i have more than enough
>> usb ports on my backpanel.
>>
>> Tried the gpu method by adding the id of the device in modprobe.d after
>> gpu's ids but it didn't work.
>>
>> I paid it 50euros :(
>> Thanks for the explanations alex
>>
>>
>> 2016-01-15 18:59 GMT+01:00 Alex Williamson <alex.williamson at redhat.com>:
>>
>>> A couple comments, first, boot time pre-binding to vfio-pci is really
>>> only necessary for devices where the native host drivers behave poorly
>>> if you take the device away from them later.  This is why we do it for
>>> GPUs and their companion sound device, host GPU drivers don't like to
>>> give up the device, it plays poorly with any sort of graphics on the
>>> host, and sequestering the audio device prevents host tools from
>>> getting confused (and there are some bugs in the audio driver limiting
>>> number of attach/detach cycles iirc).
>>>
>>> For anything else, you can dynamically unbind the device from the host
>>> driver, bind it to vfio while the VM is running, and give it back to
>>> the host on shutdown.  libvirt will do this automatically for you if
>>> your XML sets managed='yes' for the <hostdev> device.  This is the
>>> default, so if you use virt-manager to add the device, just select Add
>>> Hardware -> PCI Host Device -> select device -> Finish.  Done.  If for some
>>> reason you don't want the device flopping back and forth between host and
>>> guest, just run 'virsh nodedev-detach pci_0000_xx_yy_z' at bootup where
>>> xx_yy_z is the PCI bus (xx), device (yy), and function (z) numbers, the
>>> same as in lspci.  You can adopt some of the GPU methods for doing this if
>>> you want it to happen earlier as well, there are lots of ways to do this
>>> with modprobe.d (install options, softdep, etc..)
>>>
>>> Finally, yes I've seen OVMF hang with some crappy USB controllers.  I'm
>>> not sure if it's dependent on the devices attached or the controller
>>> itself, but cheaper isn't always better when it comes to selecting
>>> devices to use with device assignment.  Thanks,
>>>
>>> Alex
>>>
>>
>>
>
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