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 for <linuxppc-dev@lists.ozlabs.org>; Wed, 11 Jul 2012 10:47:53 +1000 (EST)
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Date: Tue, 10 Jul 2012 19:47:41 -0500
From: Scott Wood <scottwood@freescale.com>
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To: Alexander Graf <agraf@suse.de>
Subject: Re: [PATCH] powerpc/booke: Eliminate rfi from exception entry path.
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Cc: linuxppc-dev@lists.ozlabs.org, Stuart Yoder <stuart.yoder@freescale.com>
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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