igb VF allocation with quirk_i82576_sriov

igb VF allocation with quirk_i82576_sriov

[Chris Wright]

Is this known to work?  During recent virt testing for upcoming Fedora 12,
a box w/out SR-IOV support in BIOS was using quirk to create VF BAR space,
VF allocation worked enough to assign a device to the guest, but igbvf
was not actually functioning properly in the guest.

Is it worth debugging this further, or is it already a known issue?

thanks,
-chris

Re: igb VF allocation with quirk_i82576_sriov

[Alexander Duyck]

Chris Wright wrote:
> Is this known to work?  During recent virt testing for upcoming Fedora 12,
> a box w/out SR-IOV support in BIOS was using quirk to create VF BAR space,
> VF allocation worked enough to assign a device to the guest, but igbvf
> was not actually functioning properly in the guest.
> 
> Is it worth debugging this further, or is it already a known issue?

You could be experiencing one of a couple different issues.

First when you say you started SR-IOV on a box w/out SR-IOV support I 
assume you are using "pci=assign-busses" in order to reserve the bus 
space for the VFs, is that correct?  Also while your system may not 
support SR-IOV does it at least support VT-d?  Without VT-d support you 
won't be able to assign a device to the guest.

My recommendations for further testing would be to test a VF on the host 
kernel to see if that works.  If it does then you could also try direct 
assigning an entire port to see if that works.  If the entire port 
doesn't work then you probably don't have VT-d enabled.

Thanks,

Alex

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Re: igb VF allocation with quirk_i82576_sriov

[Chris Wright]

* Alexander Duyck (alexander.h.duyck@intel.com) wrote:
> Chris Wright wrote:
>> Is this known to work?  During recent virt testing for upcoming Fedora 12,
>> a box w/out SR-IOV support in BIOS was using quirk to create VF BAR space,
>> VF allocation worked enough to assign a device to the guest, but igbvf
>> was not actually functioning properly in the guest.
>>
>> Is it worth debugging this further, or is it already a known issue?
>
> You could be experiencing one of a couple different issues.
>
> First when you say you started SR-IOV on a box w/out SR-IOV support I  
> assume you are using "pci=assign-busses" in order to reserve the bus  
> space for the VFs, is that correct?  Also while your system may not  
> support SR-IOV does it at least support VT-d?  Without VT-d support you  
> won't be able to assign a device to the guest.

VT-d was definitely there, as for the rest I'll have to ask the tester
for more details.  I just wanted to verify that it's a known working
combo before spending more time on it.

Regarding the bus numbering, I don't think there's a bus issue.
The PF+VFs all stay w/in same bus segment despite large offset and the
stride (IIRC, this was only device on bus 2, a dual port igb on .0 and .1.
the offset is 128 and stride is 2, so even w/ 8 VFs the max device would
be something like 2:11.7 or 2:12.0).

> My recommendations for further testing would be to test a VF on the host  
> kernel to see if that works.  If it does then you could also try direct  
> assigning an entire port to see if that works.  If the entire port  
> doesn't work then you probably don't have VT-d enabled.

Yeah, IIRC, igbvf at least loaded on the host (on the guest too, after
unbinding host driver).  I didn't get a chance to see if VF passed
traffic on the host, and from the report, it wasn't able to get a dhcp
address in the guest.  Will dig into it a bit more after plumbers.

thanks,
-chris

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