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

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

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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.

Jan


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