openbsd system_powerdown: "KVM internal error. Suberror: 1"

[Michael Tokarev <mjt@tls.msk.ru>]

Hello.

I installed an openbsd 4.8 image today to play with,
and noticed that when issuing "system_powerdown" in
kvm monitor, in about 5 seconds, qemu-kvm spews this
message in a tight loop:

 KVM internal error. Suberror: 1
 emulation failure
 KVM internal error. Suberror: 1
 emulation failure
 ....

ad infinitum, until interrupted.

I verified the issue exists in 0.14 and 0.12 qemu-kvm,
both 32 and 64bits.

Freebsd does not trigger this behavour, it is running
normally.

kvm-0.12.5 behaves somewhat more sane in this case too,
it prints some more information:

 KVM internal error. Suberror: 1
 rax 0000000000000030 rbx 0000000000000000 rcx 0000000000000000 rdx 000000000000b100
 rsi 00000000d0201fc6 rdi 00000000d0ac1ad4 rsp 00000000d9651004 rbp 00000000d9759a38
 r8  0000000000000000 r9  0000000000000000 r10 0000000000000000 r11 0000000000000000
 r12 0000000000000000 r13 0000000000000000 r14 0000000000000000 r15 0000000000000000
 rip 00000000d0202041 rflags 00000292
 cs 0050 (00000000/ffffffff p 1 dpl 0 db 1 s 1 type b l 0 g 1 avl 0)
 ds 0010 (00000000/ffffffff p 1 dpl 0 db 1 s 1 type 3 l 0 g 1 avl 0)
 es 0010 (00000000/ffffffff p 1 dpl 0 db 1 s 1 type 3 l 0 g 1 avl 0)
 ss 0010 (00000000/ffffffff p 1 dpl 0 db 1 s 1 type 3 l 0 g 1 avl 0)
 fs 0058 (d0ac1aa0/000003db p 1 dpl 0 db 0 s 1 type 3 l 0 g 0 avl 0)
 gs 0010 (00000000/ffffffff p 1 dpl 0 db 1 s 1 type 3 l 0 g 1 avl 0)
 tr 0078 (d9758000/00000333 p 1 dpl 0 db 0 s 0 type b l 0 g 0 avl 0)
 ldt 0018 (d0a31580/00000087 p 1 dpl 0 db 0 s 0 type 2 l 0 g 0 avl 0)
 gdt d9575000/ffff
 idt d0a31620/7ff
 cr0 8001003b cr2 dcd0000 cr3 1f202000 cr4 780 cr8 3 efer 0
 emulation failure, check dmesg for details

As far as I can see, this is just a one-time message in 0.12.
Dmesg (on host) is completely silent.

-no-kvm-irqchip does not help either (I tried it for a different
reason but decided to check this case too, while at it).

Host kernel is 2.6.37-2 (with e5d135f80b98b0 + 2607b0533353c
applied after yesterdays freebsd issues), 64bit, running on
amd AthlonII CPU.  In all cases guests were with -smp 1, and
without any fancy options (just -hda & -m).  Openbsd 4.8 32bit.

I see two issues here: one is the emulation failure and another
is the erratic behavour of kvm-0.14 - issuing that error message
in a tight loop.

Thanks!

/mjt