Bhyve process consumes way too much CPU

Hey everyone,

I'm running Linux (Home Assistant OS) in Bhyve on FreeBSD 13.1. I use PCI
passthrough to allow the VM to access a USB card with a couple of radio
dongles. The host machine is an Intel Core i3 13100 with 64 GB of RAM. The
CPU has 4 physical cores (8 hyper-threaded). The virtual machine is
assigned four cores.

The host load averages are 0.39 0.39 0.40 right now, which seems way too
much. The same workload was previously handled by a Raspberry Pi 4, and the
CPU usage there was under 10% when not doing anything special. Inside the
guest OS, the CPU usage is reported around 5%, which seems reasonable.

What's wrong? How can I start debugging this issue? I use ZFS on the host,
vm-bhyve to manage the virtual machines, and I don't have a swap partition.

Thanks for your help,
Julie