It's still an option in VM settings in the Admin WebUI for guest OS selection. oVirt should still support it.
I've even gotten Windows NT 4.0 Workstation to run within oVirt. (With PCI passthough for an old SCSI device.) I wouldn't expect support from oVirt for *that* use case, but Windows 7 is still something I would expect any modern VM software to support. (As of this writing.)
Never mind that one of the reasons to run a VM in the first place is to run (older) software that needs a specific environment to run. Which the main host environment cannot support. I can understand RedHat wanting to reduce it's workload, but developers constantly deprecating support is one of the bigger problems with OSS at the moment. Many people go the OSS route initially for legacy support. (Can't afford the upgrade treadmill.) Cutting that out and forcing people to buy new every time is just going to make them stick with the new thing they bought. While creating a negative view of OSS that they will then spread to others. oVirt as a community project shouldn't be encouraging that.
As for the original question...
You might try removing any extra USB drivers you have installed. (Especially the NEC drivers if you've still got them in there.) Also is that hook from your previous mail still active? If it is, you can try creating a new VM and attach the existing disk to it. (So you won't have to reinstall Win7 again.) That should give it a default config.
If all else fails, you may need to reinstall Win7 under a new VM profile to get it working again.
If you absolutely need USB3 support under Win7, you could try doing a passthrough of a USB controller on the host system. (You won't be able to use that controller on the host if you do.) That would allow you to use a PCI USB controller card with the appropriate drivers for Windows 7. Granted it's counter to my point above, but at the moment, I don't see how Windows 7 would get USB3 support from qemu / KVM. Short of someone taking the time to write a new virtio driver from scratch. Which has been asked for previously to no avail.
On Mon, 2022-06-06 at 13:58 +0200, Sandro Bonazzola wrote:
It's observed that win7 guest will become no response if i eject usb storage "Eject MiniKing"
the last screen after i clicked "Eject MingKing":
After that, i have to hard reset the guest.