Re: [PATCH kvm-unit-tests] arm: fix crash when caches are off

[Andrew Jones <drjones@redhat.com>]

----- Original Message -----
> 
> 
> ----- Original Message -----
> > Il 16/09/2014 14:12, Andrew Jones ha scritto:
> > >> > Should it at least write 1 to the spinlock?
> > > I thought about that. So on one hand we might get a somewhat functional
> > > synchronization mechanism, which may be enough for some unit test that
> > > doesn't enable caches, but still needs it. On the other hand, we know
> > > its broken, so we don't really want any unit tests that need
> > > synchronization
> > > and don't enable caches. I chose to not write a 1 in the hope that if
> > > a unit test introduces a race, that that race will be easier to expose
> > > and fix. That said, I'm not strongly biased, as we'd still have a race,
> > > which may or may not be easy to expose, either way. So if the majority
> > > prefers a best effort approach, then I'll spin a v2.
> > 
> > The case I was thinking about was something like
> > 
> >     spin_lock()
> >     enable caches
> >     start other processors
> >     spin_unlock()
> > 
> > I'm not sure if it makes sense though. :)
> 
> I don't think we need to worry about this case. AFAIU, enabling the
> caches for a particular cpu shouldn't require any synchronization.
> So we should be able to do
> 
>     enable caches
>     spin_lock
>     start other processors
>     spin_unlock
> 

Oh drat. I just introduced an issue with enabling caches without working
spin locks. This new boolean. This boolean will need to be per cpu.

I'll send a v2.



> drew
> 
> > 
> > Paolo
> > 
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