Unexpected ahci-hd bytes when running in bhyve(8)

[Harry Schmalzbauer]

 Bezüglich Harry Schmalzbauer's Nachricht vom 29.10.2016 17:32 (localtime):

…
> Like mentioned, while reading the first 448 bytes on the host, I get
> identical results from /usr/local/guest.img and /dev/ada4, but when
> attaching /dev/ada4 to ahci-hd (-s 7,ahci-hd,/dev/ada4) and inspecting
> inside vmm, all I see is 0x0, while ahci-hd attached
> /usr/local/guest.img shows the same pmbr as on the host!?
>
> Do I have to exclude /dev/ada4 on the host from geom? As soon as bhyve
> opens /dev/ada4, all partitions vanish from the host – probably ada4
> itself gets blocked somehow?

Maybe that's related?
https://lists.freebsd.org/pipermail/freebsd-virtualization/2015-April/003509.html
(resulting in https://svnweb.freebsd.org/base?view=revision&revision=281700)

Just another symptom I can only describe, not debug:
Opening /dev/adaX on the host works by 'hd /dev/ada4 | less',
but not inside the guest, where it just leads to endless IO when trying
the same on the ahci-hd attached /dev/ada4.

Of course I found discussion threads about virtio-scsi, which was more
appropriate for my needs, but unfortunately nobody skilled enough had
time to implement yet afaik and it also wouldn't solve my problems while
this ssd is SATA attached (could switch to a SAS port so the HBA would
do SAT which should work then...)
Are there any other ways I'm missing to get mass storage into the guest?
ZVOl is a very good candidate for many setups, but not for all.
RAw-device-mappings to HBA-virtual-drives is doing a great job on ESXi,
but replacing HBA-virt-drive RAW-mappings with ZVOL isn't really the
same and sometimes I need physical devices in the guest.
P(cie)P(ass)T(through) seems to work great in bhyve, but I can't
sacrifice a complete HBA to accomplish.

Thanks,

-harry