Intel I350 SR-IOV Suddenly Stopped Working While Hyper-V Still Not Reporting as Network as Degraded

Question

After working for almost a year without issues, SR-IOV functionality suddenly quit working. The NIC is an Intel I350-T4 and the OS is Windows Server 2012 R2.
Looking at the event logs in the parent, here's an example of the message indicating failure:
Log Name:      Microsoft-Windows-Hyper-V-SynthNic-Admin
Source:        Microsoft-Windows-Hyper-V-SynthNic
Date:          3/21/2014 2:12:18 PM
Event ID:      12585
Task Category: None
Level:         Warning
Keywords:      
User:          NT VIRTUAL MACHINE\5AEE01AC-A4BC-4C66-B83A-54F9A0FF87C7
Computer:      [removed from public post]
Description:
'ADDS01' Network Adapter (5aee01ac-a4bc-4c66-b83a-54f9a0ff87c7--ac9784d3-e52c-4334-ac68-465a9a853454) failed to allocate a virtual function: The request is not supported. (0x80070032): IOV networking might be incompatible with other configured networking features.
(Virtual Machine ID 5AEE01AC-A4BC-4C66-B83A-54F9A0FF87C7)
Looking in one of the affected Windows VMs, the following log entry is reported:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="v1q" />
    <EventID Qualifiers="40964">27</EventID>
    <Level>3</Level>
    <Task>0</Task>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2014-03-21T18:12:23.582053900Z" />
    <EventRecordID>203556</EventRecordID>
    <Channel>System</Channel>
    <Computer>[removed from public post]</Computer>
    <Security />
  </System>
  <EventData>
    <Data>
    </Data>
    <Data>Intel(R) I350 Virtual Function</Data>
    <Binary>0000040002003000000000001B0004A00000000000000000000000000000000000000000000000001B0004A0</Binary>
  </EventData>
</Event>
I've looked at John Howard's detailed, "Everything you wanted to know about SR-IOV in Hyper-V" series and followed the steps in part 8 (http://blogs.technet.com/b/jhoward/archive/2012/03/21/everything-you-wanted-to-know-about-sr-iov-in-hyper-v-part-8.aspx)
to see if that would lead me to the resolution. Unfortunately, most of the error conditions that he mentions are paired with a 'Degraded' status and status messages with suggested reasons.
Unfortunately, the network connections in my case are listed as 'OK', and so I'm not sure where to go next to find out what changed and why SR-IOV is enabled on the NIC, virtual switch, and virtual NIC... and yet still not functional and not reporting as
degraded.
Any help would be greatly appreciated.
Thanks!
Paul

Answer 1

Thought I would add this information to this thread since it came up while I was trying to figure out my issue. It turns out that the Network adapters on my motherboard the I350-AM4 support SR-IOV based on Intels website
http://ark.intel.com/products/52966/Intel-Ethernet-Controller-I350-AM4
But my motherboard manufacture for some reason has disabled this functionality.
http://www.asus.com/support/FAQ/1007259/
So the lesson learned here is to check both the Adapter support and the motherboard support for SR-IOV. I still don't understand why the same exact NPU would have SR-IOV disabled but yet use the same drivers with the option to turn on SR-IOV... VMDq does
work though fyi.
http://WrinkleFreeIT.com/