The bhyve kernel module and its associated userland consumers have been updated
to the latest upstream FreeBSD sources as of:

commit 8ade7383cafed0f7555cac16ef7f9e956e46eaeb
Author: grehan <grehan@FreeBSD.org>
Date:   Mon May 25 06:25:31 2020 +0000

    Fix pci-passthru MSI issues with OpenBSD guests

    - Return 2 x 16-bit registers in the correct byte order
     for a 4-byte read that spans the CMD/STATUS register.
      This reversal was hiding the capabilities-list, which prevented
     the MSI capability from being found for XHCI passthru.

    - Reorganize MSI/MSI-x config writes so that a 4-byte write at the
     capability offset would have the read-only portion skipped.
      This prevented MSI interrupts from being enabled.

     Reported and extensively tested by Anatoli (me at anatoli dot ws)

    PR:     245392
    Reported by:    Anatoli (me at anatoli dot ws)
    Reviewed by:    jhb (bhyve)
    Approved by:    jhb, bz (mentor)
    MFC after:      1 week
    Differential Revision:  https://reviews.freebsd.org/D24951

Divergence Notes:
A previous sync skipped commit c8edafdabc27533d9c51eddc2896e772c16d965c which
introduced a generic backend functionality to network devices.  Without that in
place, subsequent updates reflect the absence of that subsystem.  Integrating
net backends has not been a priority, given the common use of viona on illumos.

The draft Save/Restore functionality, added in FreeBSD commit
d3e4e512238b072fb9282e024610b981ba679869, has not been synced into illumos bhyve
yet.  It is not built by default in FreeBSD, so we're not interested in taking
it until it successfully endures more in-depth testing.