Re: [Qemu-devel] KVM VM(windows xp) reseted when running geekbench for about 2 days

[Gleb Natapov]

On Fri, Apr 19, 2013 at 01:05:08AM +0000, Zhanghaoyu (A) wrote:
> >> On Thu, Apr 18, 2013 at 12:00:49PM +0000, Zhanghaoyu (A) wrote:
> >>> I start 10 VMs(windows xp), then running geekbench tool on them, 
> >>> about 2 days, one of them was reset, I found the reset operation is 
> >>> done by int kvm_cpu_exec(CPUArchState *env) {
> >>>    ...
> >>>       switch (run->exit_reason)
> >>>       ...
> >>>        case KVM_EXIT_SHUTDOWN:
> >>>            DPRINTF("shutdown\n");
> >>>            qemu_system_reset_request();
> >>>            ret = EXCP_INTERRUPT;
> >>>            break;
> >>>    ...
> >>> }
> >>> 
> >>> KVM_EXIT_SHUTDOWN exit reason was set previously in triple fault handle 
> >>> handle_triple_fault().
> >>> 
> >> How do you know that reset was done here? This is not the only place 
> >> where qemu_system_reset_request() is called.
> I used gdb to debug QEMU process, and add a breakpoint in 
> qemu_system_reset_request(), when the case occurred, backtrace shown as below,
> (gdb) bt
> #0  qemu_system_reset_request () at vl.c:1964
> #1  0x00007f9ef9dc5991 in kvm_cpu_exec (env=0x7f9efac47100)
>     at /gt/qemu-kvm-1.4/qemu-kvm-1.4/kvm-all.c:1602
> #2  0x00007f9ef9d5b229 in qemu_kvm_cpu_thread_fn (arg=0x7f9efac47100)
>     at /gt/qemu-kvm-1.4/qemu-kvm-1.4/cpus.c:759
> #3  0x00007f9ef898b5f0 in start_thread () from /lib64/libpthread.so.0
> #4  0x00007f9ef86fa84d in clone () from /lib64/libc.so.6
> #5  0x0000000000000000 in ?? ()
> 
> And, I add printk log in all place where KVM_EXIT_SHUTDOWN exit reason is 
> set, only handle_triple_fault() was called.
> >
> >Make sure XP is not set to auto-reset in case of BSOD. 
> No, winxp is not set to auto-reset in case of BSOD. No Winxp event log 
> reported.
> >
> >Best regards,
> >Yan.
> >
> >> 
> >>> What causes the triple fault?
> >>> 
> >> Are you asking what is triple fault or why it happened in your case?
> What I asked is why triple fault happened in my case.
> >> For the former see here: http://en.wikipedia.org/wiki/Triple_fault
> >> For the later it is to late to tell after VM reset. You can run QEMU 
> >> with -no-reboot -no-shutdown. VM will pause instead of rebooting and 
> >> then you can examine what is going on.
> Great thanks, I'll run QEMU with -no-reboot -no-shutdown options, if VM 
> paused in my case, what should I examined?
> 
Register state "info registers" in the monitor for each vcpu. Code
around the instruction that faulted.

--
                        Gleb.