Re: Freebsd image from Qemu hangs on booting in KVM

From: Anjali Kulkarni
Date: Thu Aug 05 2010 - 17:51:53 EST

Ok, I could reproduce the problem, and also get the info you asked for:

(qemu) info registers
EAX=00000000 EBX=c27166c0 ECX=00000013 EDX=c0bf85e0
ESI=c057cea0 EDI=00000000 EBP=d35a5ce4 ESP=d35a5ce4
EIP=c09e48ba EFL=00000246 [---Z-P-] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0028 00000000 ffffffff 00c09300
CS =0020 00000000 ffffffff 00c09b00
SS =0028 00000000 ffffffff 00c09300
DS =0028 00000000 ffffffff 00c09300
FS =0008 c0c6c900 ffffffff 00c09300
GS =003b 00000000 ffffffff 00c0f300
LDT=0050 c0c6c720 00000087 0000e200
TR =0048 c0c6c940 00000067 00008b00
GDT= c0c6c680 00000097
IDT= c0c6db40 000007ff
CR0=e005003b CR2=4808e000 CR3=1f54e000 CR4=00000090
DR0=00000000 DR1=00000000 DR2=00000000 DR3=00000000
DR6=ffff0ff0 DR7=00000400
FCW=127f FSW=0000 [ST=0] FTW=00 MXCSR=00000000
FPR0=0000000000000000 0000 FPR1=0000000000000000 0000
FPR2=0000000000000000 0000 FPR3=0000000000000000 0000
FPR4=0000000000000000 0000 FPR5=0000000000000000 0000
FPR6=0000000000000000 0000 FPR7=0000000000000000 0000
(qemu) x/30i $eip-20
0x00000000c09e48a6: add %al,(%eax)
0x00000000c09e48a8: leave
0x00000000c09e48a9: ret
0x00000000c09e48aa: push %ebp
0x00000000c09e48ab: mov %esp,%ebp
0x00000000c09e48ad: leave
0x00000000c09e48ae: ret
0x00000000c09e48af: push %ebp
0x00000000c09e48b0: mov %esp,%ebp
0x00000000c09e48b2: hlt
0x00000000c09e48b3: jmp 0xc09e48b2
0x00000000c09e48b5: push %ebp
0x00000000c09e48b6: mov %esp,%ebp
0x00000000c09e48b8: sti
0x00000000c09e48b9: hlt
0x00000000c09e48ba: leave
0x00000000c09e48bb: ret
0x00000000c09e48bc: push %ebp
0x00000000c09e48bd: mov %esp,%ebp
0x00000000c09e48bf: mov %cr0,%eax
0x00000000c09e48c2: or $0x5002a,%eax
0x00000000c09e48c7: mov %eax,%cr0
0x00000000c09e48ca: movl 0xc0c6c888,%gs
0x00000000c09e48d0: leave
0x00000000c09e48d1: ret
0x00000000c09e48d2: push %ebp
0x00000000c09e48d3: mov %esp,%ebp
0x00000000c09e48d5: sub $0x8,%esp
0x00000000c09e48d8: mov %ebx,(%esp,1)
0x00000000c09e48db: mov %esi,0x4(%esp,1)

On 8/5/10 1:51 PM, "Anjali Kulkarni" <anjali@xxxxxxxxxxx> wrote:

> Thanks Avi,
> I am trying to reproduce this on another setup, and do not see the issue.
> My understanding is to run KVM + Qemu, I only need to install KVM modules,
> and Qemu does not need to be modified. Is that correct?
> I see
> [root@ipg-virt01 anjali]# lsmod | grep kvm
> kvm_intel 87016 0
> kvm 211496 1 kvm_intel
> [root@ipg-virt01 anjali]# modprobe -l 'kvm*'
> /lib/modules/2.6.18-164.el5/kernel/extra/kvm.ko
> /lib/modules/2.6.18-164.el5/kernel/extra/kvm-amd.ko
> /lib/modules/2.6.18-164.el5/kernel/extra/kvm-intel.ko
> And then I run Qemu, as I did, before installing KVM. It should just use
> KVM? Is there any way I can check?
> Btw, when it hangs, I cannot even press any key, so not sure how I can get
> those commands you suggest below..
> Anjali
> On 8/5/10 1:46 AM, "Avi Kivity" <avi@xxxxxxxxxx> wrote:
>> On 08/05/2010 05:20 AM, Anjali Kulkarni wrote:
>>> Hi,
>>> I have a problem similar to the one seen on this list before - when I boot
>>> my
>>> freebsd based(but modified) image in Qemu with KVM on CentOS, then after
>>> almost booting completely, the image hangs - just before the login prompt is
>>> seen. If I do not have KVM ie plain CenOS with Qemu, then this issue does
>>> not
>>> occur. Has anyone seen this before and any ideas how to debug this?
>> First step is to issue 'info registers' and 'x/30i $eip-20' from the
>> monitor when it hangs (qemu -monitor stdio makes cut'n'paste easier).

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