GPT scheme. UEFI needs to know the unique partition GUID
with GPT, which changes each time. Specifically, the QEMU
EFI BIOS file has this hard-coded.[1]
Since the GPT labels are now unavailable, unconditionally
label the root filesystem as 'rootfs' with newfs(8), since
it does not hurt anything anywhere else. For the arm64 case,
'/' is mounted from /dev/ufs/rootfs; for all other VM images,
'/' is mounted from /dev/gpt/rootfs.
Unfortunately, since the /dev/gpt/swapfs label is also lost,
set NOSWAP=1 for the arm64/aarch64 images. This is temporary,
until I figure out a scalable solution to this. But, a certain
piece of softare was written "very fast", and ended up living
for 15 years. We can deal with this for a week or so.
Information from: andrew, emaste [1]
Sponsored by: The FreeBSD Foundation
09615c77fe