Re: -smp >=2 + -no-kvm-irqchip broken

[Jan Kiszka <jan.kiszka@web.de>]

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Gleb Natapov wrote:
> On Tue, Feb 02, 2010 at 07:56:42PM +0100, Jan Kiszka wrote:
>> Jan Kiszka wrote:
>>> Gleb Natapov wrote:
>>>> On Tue, Feb 02, 2010 at 05:41:03PM +0100, Jan Kiszka wrote:
>>>>> Gleb Natapov wrote:
>>>>>> On Tue, Feb 02, 2010 at 05:29:53PM +0100, Jan Kiszka wrote:
>>>>>>> Hi,
>>>>>>>
>>>>>>> notice while testing v2 of my vcpu state series: Starting SMP guests
>>>>>>> like Linux or Vista without in-kernel irqchip and with more than one CPU
>>>>>>> make them lock up during boot (Vista) or spit out messages like
>>>>>>>
>>>>>>> udevd[112] trap invalid opcode ip:7fc434630950 sp:7fff3cd3fcb8 error:0
>>>>>>> in libc-2.9.so[7fc4345b2000+14f000]
>>>>>>>
>>>>>> Looks like interrupt is injected as exception. Can you try to bisect?
>>>>> Already started (as low prio background task), first looking for a good
>>>>> version. If you know a recent one, I'm a taker.
>>>>>
>>>> Nope, didn't try no kernel irqchip for a long time.
>>> Kernel plays the key role here, either kvm-kmod or actually the kvm
>>> module: kvm-kmod-2.6.31.6 works, the 2.6.32 series and later do not.
>>> Digging deeper...
>> I take this back: It works for Linux guests, but Vista crashes also with
>> old kvm-kmod. So there is no way around real debugging.
>>
> Upstream qemu-kvm/kvm works for me. Boot linux with -smp 2 and
> windows2008-32 with -smp 4.

We seem to have two issues:
 - kvm.git master breaks 64-bit linux guests under -no-kvm-irqchip +
   smp (#UD pop up in guest user space). 2.6.33 kvm is fine. Will try to
   bisect this the next days.
 - My Vista x64 image apparently suffer from a race (I suspect in user
   space) that lets it deadlock on a spinlock, independent of the
   underlying kernel kvm version.

Jan


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