AMD64 qemu completely broken?

[Zaphod Beeblebrox]

I decided to take the comments about testing ZFS to heart --- so I decided
to try copying my 7.0 "v6" ZFS configuration into a qemu instance and
upgrading it.  To do this, I carefully copied my UFS boot partition and my
ZFS partion to a physical USB disk that I could put on a system to do the
test.

After compiling qemu and loading the kqemu and aio kernel module, I started
the emulator, first in VNC mode.  It loaded the kernel (currently 7.1-RC)
and tried to boot, but kept failing either shortly after kbdmux detected a
keyboard or it would get through to mounting root and not find any drives.
For reference, besides the display option (ie: -vnc or whatever), my command
line was:

qemu-system-x86_64 -hda /dev/da0 -snapshot -m 512

I couldn't scroll back in VNC mode using the pause/break key, so I tried to
get qemu running directly in X.

Now... I see a few posts stating that running qemu remotely causes an X
protocol error.  I can confirm that.  Something about Qemu's use of X will
no work over an SSH remote connection (with -X), nor will it work with
dxpc.  It dies for me every time at X event sequence number 22.  Xterms
work.  Gimp even works.  qemu does not.

So I got a vnc server running to run it locally.

And now it crashes reliably in one spot.  boot0 and boot1 don't recognize
the keyboard ... but the press space after crash does.  Besides that quirk,
the 7.1-RC kernel crashes with the following transcript reliably:

MADT: Forcing active-low polarity and level trigger for SCI
kbd1 at kbdmux0
ath_hal: 0.9.20.3 (AR5210, AR5211, AR5212, RF5111, RF5112, RF2413, RF5413)


Fatal trap 9: general protection fault while in kernel mode
cpuid = 0; apic id=00
instruction pointer             = 0x8:0xffff

... and so on.

I'd like to test this... has anyone any successes with the AMD64 qemu?