Subject: Re: [PATCH] powerpc/booke: Eliminate rfi from exception entry path.

From: Scott Wood <[email-masked]>
Date: Tue, 10 Jul 2012 19:47:41 -0500

On 07/10/2012 07:44 PM, Alexander Graf wrote:
> 
> On 11.07.2012, at 02:34, Scott Wood wrote:
>> +#ifdef CONFIG_BOOKE
>> +	/*
>> +	 * We're not changing address space on Book E, and the extra rfi
>> +	 * can hurt when virtualized without hardware support -- whereas
>> +	 * mtmsr can be paravirtualized.
> 
> We can always paravirtualize RFI as well if it makes sense.

I'm not sure that's possible.  We thought about it a while back, but
IIRC the difficulty was not leaving a register clobbered.

-Scott