Re: KVM guest crashes

[Alexander Graf <agraf@suse.de>]

Marcelo Tosatti wrote:
> On Mon, Jan 26, 2009 at 04:53:21PM +0100, Alexander Graf wrote:
>   
>>> There are a number of problems that can result in this error, and the
>>> problems are possibly different between the in-kernel PIT and userspace
>>> PIT emulation (note it also happens with in-kernel PIT, just much more
>>> rarely now). You can use the no_timer_check kernel option to bypass it.
>>>   
>>>       
>> Hm - that option disables the whole check, making it always fail. I
>> haven't seen any way to actually disable the check, telling Linux things
>> are OK :-(.
>>     
>
> Hum, the option makes timer_irq_works always return true. Works for me
> with in-kernel PIT.
>
> What you see with "apic=debug no_timer_check" ?
>   


It does work with "noapic" for me, but that means I'm using the old PIC
(which isn't necessarily bad, right?). So I can at least work around the
issue for us now. It still needs to be fixed nevertheless.

with "apic=debug no_apic_timer" 2.6.27 does:

Setting APIC routing to flat
..TIMER: vector=0x30 apic1=0 pin1=0 apic2=-1 pin2=-1
..MP-BIOS bug: 8254 timer not connected to IO-APIC
...trying to set up timer (IRQ0) through the 8259A ...
..... (found apic 0 pin 0) ...
....... works.


while 2.6.25 does:

..MP-BIOS bug: 8254 timer not connected to IO-APIC
Kernel panic - not syncing: IO-APIC + timer doesn't work! Try using the
'noapic' kernel parameter