Subject: Re: [v1][PATCH 1/1] KVM: PPC: disable preemption when using hard_irq_disable()

From: Scott Wood <[email-masked]>
Date: Wed, 10 Jul 2013 14:15:40 -0500

On 07/10/2013 01:02:19 AM, Tiejun Chen wrote:
> We should ensure the preemption cannot occur while calling get_paca()
> insdide hard_irq_disable(), otherwise the paca_struct may be the
> wrong one just after. And btw, we may update timing stats in this =20
> case.

The soft-ee mechanism depends on accessing the PACA directly via r13 to =20
avoid this.  We probably should be using inline asm to read was_enabled =20
rather than hoping the compiler doesn't do anything silly.

Plus what Alex said, regarding this patch specifically.

-Scott=