Re: regression in v3.9? a guest stuck in BIOS if emulate_invalid_guest_state=Y

["Jun'ichi Nomura" <j-nomura@ce.jp.nec.com>]

On 05/08/13 12:22, Jun'ichi Nomura wrote:
>> Il 07/05/2013 14:06, Gleb Natapov ha scritto:
>>> What is the output of "virsh qemu-monitor-command vm12 --hmp x/i $pc"
>>> when it hangs?
> 
> # virsh qemu-monitor-command vm12 --hmp x/4i \$pc
> 0x00000000000c06ca:  aam    $0xa
> 0x00000000000c06cc:  mov    %ax,%bx
> 0x00000000000c06ce:  mov    %bh,%al
> 0x00000000000c06d0:  aam    $0xa
> 
> # virsh qemu-monitor-command vm12 --hmp x/8b \$pc
> 00000000000c06ca: 0xd4 0x0a 0x89 0xc3 0x88 0xf8 0xd4 0x0a

I could also reproduce the problem with following:

# dd if=/dev/zero of=/root/empty.img bs=1M count=1
# /usr/libexec/qemu-kvm -enable-kvm -nographic -nodefconfig -nodefaults -chardev socket,id=cmon,host=localhost,port=8888,server,nowait -mon chardev=cmon,mode=readline -drive file=/root/empty.img -chardev stdio,id=ser0 -device isa-serial,chardev=ser0

With v3.8 kernel, it reaches to the point showing "No bootable device"
(as expected).
With v3.9 kernel, no visible characters appear on console.

EIP of the stalled guest points to other instruction than the
previously reported case though:

(qemu) info registers
info registers
EAX=f000e81b EBX=00000130 ECX=0000fa2b EDX=0000031b
ESI=000000ed EDI=00000050 EBP=00000000 ESP=00006eaa
EIP=00000564 EFL=00000046 [---Z-P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0040 00000400 ffffffff 00809300
CS =c000 000c0000 ffffffff 00809b00
SS =0000 00000000 ffffffff 00809300
DS =c000 000c0000 ffffffff 00809300
FS =0000 00000000 ffffffff 00809300
GS =0000 00000000 ffffffff 00809300
LDT=0000 00000000 0000ffff 00008200
TR =0000 00000000 0000ffff 00008b00
GDT=     000fc558 00000037
IDT=     00000000 000003ff
CR0=00000010 CR2=00000000 CR3=00000000 CR4=00000000
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000 
DR6=ffff0ff0 DR7=00000400
FCW=037f FSW=0000 [ST=0] FTW=00 MXCSR=00001f80
FPR0=0000000000000000 0000 FPR1=0000000000000000 0000
FPR2=0000000000000000 0000 FPR3=0000000000000000 0000
FPR4=0000000000000000 0000 FPR5=0000000000000000 0000
FPR6=0000000000000000 0000 FPR7=0000000000000000 0000
XMM00=00000000000000000000000000000000 XMM01=00000000000000000000000000000000
XMM02=00000000000000000000000000000000 XMM03=00000000000000000000000000000000
XMM04=00000000000000000000000000000000 XMM05=00000000000000000000000000000000
XMM06=00000000000000000000000000000000 XMM07=00000000000000000000000000000000
(qemu) 
(qemu) x/8b $pc
x/8b $pc
00000000000c0564: 0xd7 0x1f 0x24 0x7f 0x88 0xc4 0x88 0xd0
(qemu) 
(qemu) x/i $pc
x/i $pc
0x00000000000c0564:  xlat   %ds:(%bx)

-- 
Jun'ichi Nomura, NEC Corporation