Windows VM hangs on boot with Hyper-V enabled on Alder Lake

[rgrama]

Hi,

I've recently setup an Intel I5-12600 as a Proxmox host and I can't get Windows VMs with the hypervisor platform enabled to boot with the CPU set to host (boots just fine with the KVM64 CPU). The same VM boots just fine on a different Intel based Proxmox host and it boots just fine. Nested virtualization is enabled, I was able to run Proxmox inside a VM and spin up another VM within it.

The problem is similar to Alder Lake 12th Gen Intel CPU won't boot on Windows Server ...https://techcommunity.microsoft.com › td-p, however the I5-12600 doesn't have any E-cores.

I also tried the Proxmox 5.15 kernel update and I have the same issue.

 

[mira]

Alder Lake CPUs are rather new.
Hyper-V in a VM on top of KVM can be tricky to get working, if at all. Support for it isn't great based on our experience here.
And with the new CPU it might require an even newer kernel than 5.15 to get it working.