From the #OpenBSD 8.0 changelog:
...

- VMM/VMD improvements:
o Added MP support for up to 64 VCPUs per guest VM.
o Redesigned to use files to manage VM ownership.
o Added x2apic mode support for guest virtual machines.
o Fix for when vmd(8) does not detect kernel on startup.
o Provide faulting GPA to vmd(8) for MMIO exits from vmm(4).
o Refactored vmm(4) exit handling and correct RIP adjustment.
o Added support for variable length instructions in VMX paths to
vmm(4).
o Prevent OOB reads by vmd(8) in 32 and 64-bit elf(5) loaders with
malformed elf(5) files.
o Implemented missing lapic/ioapic modes to fix vmd(8) support for
32-bit linux guests.
o Added checksum offload for vmd(8) guests.
o MSI/MSI-X virtio device interrupt support added.
o Support actually split split-virtqueues in vmd(8).
o Added i82093aa ioapic and i82489dx-compatible lapic emulation to
vmd(8).
o Improved qcow handling.

This is a game changer!