I'm trying to play around with a few VMs on a new machine but I can't enable IOMMU.

 

I've enabled VT-d and VT-x in bios. The only other virtualization option I see is Intel TXT which I have disabled.

 

I've attached a snip of my system info and my diagnostics.

 

Thanks!

valentine-diagnostics-20191126-0217.zip

The answer definitely lies somewhere in the bios. Got a link to the manual?

Sent from my Pixel 3 XL using Tapatalk

This is as close as I can find to a manual.

 

Also forgot to mention I briefly had Proxmox installed on this box and I don't remember having any issues with IOMMU.

What about a bios update?

Sent from my Pixel 3 XL using Tapatalk

Yeah I can try that next.  I'm on the same bios I tested Proxmox on and it's not exactly ancient.

So I finally figured out part of the mystery. Whenever I have my 4 port NIC (HP NC364T) installed, IOMMU gets disabled.

 

The next part of the mystery is why is this happening? I would like to use this NIC to passthrough to VMs at some point.

 

Also, I did update the bios to the most recent version but it made no difference with this behavior.

 

 

Did you ever make any progress on this?  I have the same issue.  VT-d is enabled via the BIOS, but when I install a 4port nic that I intend to use with VM's, iommu is disabled.