Soo..... the problem was the NIC.

I passed the NIC through to a Windows vm and it worked fine.
I passed the NIC through to a Linux VM and it was UNCLAIMED and unusable.

Checking the event logs I found the following entries :

igb 0000:00:05.0: The NVM Checksum Is Not Valid
igb 0000:00:05.0: probe with driver igb failed with error -5

For some reason Linux seems to no like that check sum failing and Windows seems to not care.

Digging around I found some people trying to re-flash firmware to resolve check sum errors and that was a dead end.
Other seems to get things working by changing some boot firmware settings.

Attaching it back to the Windows machine I ran the intel boot utility and disabled PXE boot.

BOOTUTILW64E.EXE -BOOTENABLE- DISABLED -ALL

To my surprise, I reattached to the Linux VM and was able to see and use the NIC!

Disabled the PCI pass through for the NIC and did a PIFs refresh and I now can see the device in as ETH0.

Use it on a test VM and performance is what it should be.

I suspect the boot util properly set the parameters and and updated the check sum info making Linux happy.

I am also sure this is a long way to resolve the issue and there would have been a much faster process but it was bit of a random moment of stumbling on a solution.

Posting here in hopes that it helps somebody else some day.

@Andrew using the card in windows and using bootutil64e seems to have fix it.

Soo..... the problem was the NIC.

I passed the NIC through to a Windows vm and it worked fine.
I passed the NIC through to a Linux VM and it was UNCLAIMED and unusable.

Checking the event logs I found the following entries :

igb 0000:00:05.0: The NVM Checksum Is Not Valid
igb 0000:00:05.0: probe with driver igb failed with error -5

For some reason Linux seems to no like that check sum failing and Windows seems to not care.

Digging around I found some people trying to re-flash firmware to resolve check sum errors and that was a dead end.
Other seems to get things working by changing some boot firmware settings.

Attaching it back to the Windows machine I ran the intel boot utility and disabled PXE boot.

BOOTUTILW64E.EXE -BOOTENABLE- DISABLED -ALL

To my surprise, I reattached to the Linux VM and was able to see and use the NIC!

Disabled the PCI pass through for the NIC and did a PIFs refresh and I now can see the device in as ETH0.

Use it on a test VM and performance is what it should be.

I suspect the boot util properly set the parameters and and updated the check sum info making Linux happy.

I am also sure this is a long way to resolve the issue and there would have been a much faster process but it was bit of a random moment of stumbling on a solution.

Posting here in hopes that it helps somebody else some day.

I passed the device through to a windows machine to test and was able to have it work fine.

@stormi, @gduperrey and @Andrew

Also this is the output of lshw -C network

*-network UNCLAIMED
description: Ethernet controller
product: I210 Gigabit Network Connection
vendor: Intel Corporation
physical id: 0
bus info: pci@0000:02:00.0
version: 03
width: 32 bits
clock: 33MHz
capabilities: pm msi msix pciexpress cap_list
configuration: latency=0
resources: memory:d1200000-d12fffff ioport:3000(size=32) memory:d1300000-d1303fff memory:d1100000-d11fffff

Output of lspci -v

02:00.0 Ethernet controller: Intel Corporation I210 Gigabit Network Connection (rev 03)
	Flags: fast devsel, IRQ 19
	Memory at d1200000 (32-bit, non-prefetchable) [size=1M]
	I/O ports at 3000 [size=32]
	Memory at d1300000 (32-bit, non-prefetchable) [size=16K]
	Expansion ROM at d1100000 [disabled] [size=1M]
	Capabilities: [40] Power Management version 3
	Capabilities: [50] MSI: Enable- Count=1/1 Maskable+ 64bit+
	Capabilities: [70] MSI-X: Enable- Count=5 Masked-
	Capabilities: [a0] Express Endpoint, MSI 00
	Capabilities: [100] Advanced Error Reporting
	Capabilities: [140] Device Serial Number 00-00-c9-ff-ff-00-00-00
	Capabilities: [1a0] Transaction Processing Hints
	Kernel modules: igb

Not sure I fully understand why this the igb driver is not grabbing this NIC.

@Andrew I am using 8.3.0.

yum install intel-igb-alt installed but the nic is still not available after a PIFs refresh.

Here are my two NICs from LSPCI.

01:00.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL8111/8168/8211/8411 PCI Express Gigabit Ethernet Controller (rev 15)
02:00.0 Ethernet controller: Intel Corporation I210 Gigabit Network Connection (rev 03)

Just installed a I210 Gigabit Network Connection in a small desktop for some light home labbing.

See the NIC listed under PCI devices but cannot get it to appear as a NIC after a PIFs refresh.

Is this an unsupported NIC?