Hi,
I just watched one of Wendell’s videos, an older one, about performance regression on Threadripper 2990WX, but that’s not the point. What is the point is it gave me an idea. Wendell was showing lstopo inside WSL displayed on the Windows host via Xming (I think?).
I thought, what a neat option to find out, how the CPU is actually presented to Windows from QEMU, but, that seems not the case, as Windows just presents one package with so many cores to the WSL guest.
But I went ahead anyway and installed virtual machine platform, WSL and Sandbox, just to find out.
Well, it blew my Windows guest, or so I thought at first. After several unsucessful attempts to revive the guest via (not working) safe-mode, I was thinking about how Windows must also try to establish some IOMMU stuff when adding these features?
The I removed the passed-thru GPU, and sure enough, the guest came up with a spice client. I deinstalled the features and added the GPU back, and everything is fine again.
I know, questions arise:
Snapshot? Hmm running on virtio on a physical SSD
Backup? Hmm just a test install, but must not be unecessary work.
But in the end I was left with an intriguing question: was my assumption roughly correct - at least it solved my immediate problems. But it would be nice, if someone with more know how in these matters could shed some light on the real reason and why it is so.
And regarding the initial idea: how does find out how exactly QEMU presents the CPU to a Windows guest?
cheers
Gerd