Hyper-V Discrete Device Assignment support for Precision 5820 Tower

Hello,

Same problem here with the same config...

I'm experiencing the same issue on my Precision T7910 running Windows Server 2016..

Microsoft has released a PowerShell script to assist with assessing a system's ability to support DDA, and it is available here:

https://github.com/MicrosoftDocs/Virtualization-Documentation/blob/live/hyperv-tools/DiscreteDeviceAssignment/SurveyDDA.ps1

When I run this script on my T7910 in an elevated PowerShell window, the result for potentially-assignable devices was:

"BIOS kept control of PCI Express for this device.  Not assignable."

This was true even for PCI devices that I had intentionally disabled within Computer Management on my Hyper-V host, which should have made them available to be assigned to a VM on that host.

From reading on Microsoft's sites, this error appears to be due to BIOS limitations around how VT-d is implemented:

https://blogs.technet.microsoft.com/virtualization/2015/11/20/discrete-device-assignment-machines-and-devices/

...I called Dell regarding this issue this evening, but do not currently have technical support on my T7910. Has anyone opened a ticket requesting this to be addressed? - in theory, the way to play it would be: if a Dell box is supposed to support VT-d, but the VT-d implementation is not fully/properly implementing that functionality, it would be reasonable for a purchaser of the device to request that the BIOS be updated to do so.

Thanks,

   - Nathan

Make sure vt-D is enabled, but also that ASPM (active state power management) is enabled i.e. controlled by the OS.