Re: [Qemu-devel] PCI passthrough of 40G ethernet interface (Openstack/KVM)

[Bandan Das <bsd@redhat.com>]

jacob jacob <opstkusr@gmail.com> writes:

> I also see the following in dmesg in the VM.
>
> [    0.095758] ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-ff])
> [    0.096006] acpi PNP0A03:00: ACPI _OSC support notification failed,
> disabling PCIe ASPM
> [    0.096915] acpi PNP0A03:00: Unable to request _OSC control (_OSC
> support mask: 0x08)
IIRC, For OSC control, after BIOS is done with (whatever initialization
it needs to do), it clears a bit so that the OS can take over. This message,
you are getting is a sign of a bug in the BIOS (usually). But I don't
know if this is related to your problem. Does "dmesg | grep -e DMAR -e IOMMU"
give anything useful ?

> [    0.097072] acpi PNP0A03:00: fail to add MMCONFIG information,
> can't access extended PCI configuration space under this bridge.
>
> Does this indicate any issue related to PCI passthrough?
>
> Would really appreciate any input on how to bebug this further.

Did you get a chance to try a newer kernel ?

> On Fri, Mar 13, 2015 at 10:08 AM, jacob jacob <opstkusr@gmail.com> wrote:
>>> So, it could be the i40e driver then ? Because IIUC, VFs use a separate
>>> driver. Just to rule out the possibility that there might be some driver fixes that
>>> could help with this, it might be a good idea to try a 3.19 or later upstream
>>> kernel.
>>>
>>
>> I tried with the latest DPDK release too (dpdk-1.8.0) and see the same issue.
>> As mentioned earlier, i do not see any issues at all when running
>> tests using either i40e or dpdk on the host itself.
>> This is the reason why i am suspecting if it is anything to do with KVM/libvirt.
>> Both with regular PCI passthrough and VF passthrough i see issues. It
>> is always pointing to some issue with packet transmission. Receive
>> seems to work ok.
>>
>>
>> On Thu, Mar 12, 2015 at 8:02 PM, Bandan Das <bsd@redhat.com> wrote:
>>> jacob jacob <opstkusr@gmail.com> writes:
>>>
>>>> On Thu, Mar 12, 2015 at 3:07 PM, Bandan Das <bsd@redhat.com> wrote:
>>>>> jacob jacob <opstkusr@gmail.com> writes:
>>>>>
>>>>>>  Hi,
>>>>>>
>>>>>>  Seeing failures when trying to do PCI passthrough of Intel XL710 40G
>>>>>> interface to KVM vm.
>>>>>>      0a:00.1 Ethernet controller: Intel Corporation Ethernet
>>>>>> Controller XL710 for 40GbE QSFP+ (rev 01)
>>>>>
>>>>> You are assigning the PF right ? Does assigning VFs work or it's
>>>>> the same behavior ?
>>>>
>>>> Yes.Assigning VFs worked ok.But this had other issues while bringing down VMs.
>>>> Interested in finding out if PCI passthrough of 40G intel XL710
>>>> interface is qualified in some specific kernel/kvm release.
>>>
>>> So, it could be the i40e driver then ? Because IIUC, VFs use a separate
>>> driver. Just to rule out the possibility that there might be some driver fixes that
>>> could help with this, it might be a good idea to try a 3.19 or later upstream
>>> kernel.
>>>
>>>>>> From dmesg on host:
>>>>>>
>>>>>>> [80326.559674] kvm: zapping shadow pages for mmio generation wraparound
>>>>>>> [80327.271191] kvm [175994]: vcpu0 unhandled rdmsr: 0x1c9
>>>>>>> [80327.271689] kvm [175994]: vcpu0 unhandled rdmsr: 0x1a6
>>>>>>> [80327.272201] kvm [175994]: vcpu0 unhandled rdmsr: 0x1a7
>>>>>>> [80327.272681] kvm [175994]: vcpu0 unhandled rdmsr: 0x3f6
>>>>>>> [80327.376186] kvm [175994]: vcpu0 unhandled rdmsr: 0x606
>>>>>
>>>>> These are harmless and are related to unimplemented PMU msrs,
>>>>> not VFIO.
>>>>>
>>>>> Bandan
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