How can i enable Hyperthreading in qubes?
It’s disabled by default for security - QSB #43: L1 Terminal Fault speculative side channel (XSA-273) | Qubes OS
You can enable it (at risk) by changing boot parameters in GRUB/UEFI
depending how you boot.
For example, in grub.cfg edit the kernel parameter
smt=off to “on”, or
(Someone should probably add label “waiting for upstream” to this issue)