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

Scott Wood scottwood at freescale.com
Thu Jul 11 05:15:40 EST 2013


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  
> case.

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

Plus what Alex said, regarding this patch specifically.

-Scott


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