Does anyone know how to bypass the DDA lock on Windows 10/11 Hyper-V?

SparkyTD

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The Server versions of Windows have a virtualization feature called Discrete Device Assignment that allows the user to configure PCIe passthrough, and use any PCIe device (e.g. a GPU) in a virtual machine. If I try to configure this feature on Windows 10, I get the error message "a hypervisor feature is not available to the user", which leads me to believe that the software supports the feature, but it's disabled for some reason.

I've tried to get help on other forums too, and even reached out to Microsoft's dev team, but they refuse to help me. One Hyper-V dev even told me that I shouldn't try any third party bypass if I find one, because <insert generic corporate warning garbage here>. Again, to me this implies that it's possible somehow, but they don't want me to enable it.

Maybe I'm a bit too optimistic, but I believe that this is probably something as simple as a registry flag, or different version of a Hyper-V dll file hidden somewhere in the Windows folder, that I could just copy from a server installation.

There is literally no information about this on the internet whatsoever, so I'm hoping that anyone here can help me get started with finding an "unsupported hack" that can enable DDA on Windows 10 or 11.
 

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johngalt

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Unfortunately, no, and this has been brought up in the past in other places.

First, see this post at Microsoft Docs (is that you as well?) Enabling Discrete Device Assignment on Windows 10 - Microsoft Q&A

Second, see this post from 2019 directly from Microsoft: Discrete Device Assignment -- Machines and devices

First, we're not supporting Discrete Device Assignment in Hyper-V in Windows 10. Only Server versions of Windows support this. This isn't some wanton play for more of your hard-earned cash but rather just a side effect of being comfortable supporting server-class machines. They tend to work and be quite stable.

And finally, this slightly newer post about it from 2019: Plan for deploying devices using Discrete Device Assignment

Specifically, this section: Plan for deploying devices using Discrete Device Assignment
In addition to the System Requirements for Windows Server and the System Requirements for Hyper-V, Discrete Device Assignment requires server class hardware that is capable of granting the operating system control over configuring the PCIe fabric (Native PCI Express Control). In addition, the PCIe Root Complex has to support "Access Control Services" (ACS), which enables Hyper-V to force all PCIe traffic through the I/O MMU.


These capabilities usually aren't exposed directly in the BIOS of the server and are often hidden behind other settings. For example, the same capabilities are required for SR-IOV support and in the BIOS you may need to set "Enable SR-IOV." Please reach out to your system vendor if you are unable to identify the correct setting in your BIOS.


To help ensure hardware the hardware is capable of Discrete Device Assignment, our engineers have put together a Machine Profile Script that you can run on an Hyper-V enabled host to test if your server is correctly setup and what devices are capable of Discrete Device Assignment.

So it seems you're forced to use a Server OS and server class hardware.

HTH
 

My Computer

System One

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    Windows 10 Pro X64
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