Re: [PATCH 1/4] always halt non-bsp cpu.

[Glauber Costa <glommer@redhat.com>]

On Wed, Jun 03, 2009 at 12:01:00AM +0200, Jan Kiszka wrote:
> Glauber Costa wrote:
> > On Tue, Jun 02, 2009 at 10:35:47PM +0200, Jan Kiszka wrote:
> >> Glauber Costa wrote:
> >>> This is not kvm specific, and should do fine in plain qemu
> >> This is fine with plain qemu already. The problem, IIUC, is that
> >> in-kernel kvm irqchip does not have a chance to remove the halted state
> >> again. Did you test the effect of this patch on that scenario? What
> >> makes it safe to be removed now?
> > IIRC, the in kernel irqchip sets halted = 0 in the very beginning of
> > the vcpu initialization.
> > 
> > It is tested here with in-kernel irqchip and works, so probably not
> > a problem, unless you can spot something.
> 
> At least your patch applied alone breaks -smp >1 here.
> 
> But the whole management of env->halted for the in-kernel irqchip in
> qemu-kvm is a bit hacky IMHO. Maybe it's time to rethink this. Would be
> nice to always see a consistent halted in user space, specifically for
> debugging purposes.
out of curiosity: did you apply the whole series?

please report with it. I suspect there is a change later on that might
make it work. Of course, this is no excuse, as I'm a huge fan of bisectability.
If this is the case, I'll rework the series in a way that it always work.