Re: [Xen-devel] hvm_set_callback_irq_level() deadlock?

To:	Akio Takebe <takebe_akio@xxxxxxxxxxxxxx>
Subject:	Re: [Xen-devel] hvm_set_callback_irq_level() deadlock?
From:	Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date:	Wed, 07 Jan 2009 10:31:20 +0000
Cc:	xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
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On 07/01/2009 10:22, "Akio Takebe" <takebe_akio@xxxxxxxxxxxxxx> wrote:

>> Doesn't vioapic_irq_positive_edge() clearly expect to be called with that
>> lock held?
> I concern about that vioapic_deliver() calls vcpu_kick(). If vcpu0 has the
> lock and
> vcpu1 cannot get lock and spin then vcpu0 sleep in another function,
> it may cause deadlock because vioapic_irq_positive_edge() may call
> vcpu_kick().
> For example, the following function is OK?

I still don't see the problem. You'll have to spell out a concrete example,
explaining where the two CPUs would be spinning and what state they're in
(i.e, why they are depending on each other, and why no progress can be
made).

 -- Keir

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Re: [Xen-devel] hvm_set_callback_irq_level() deadlock?