Message-ID: <47A36FF2.8000804@goop.org>
Date: Fri, 01 Feb 2008 11:16:02 -0800
From: Jeremy Fitzhardinge <jeremy@goop.org>
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To: Andi Kleen <ak@suse.de>
CC: tglx@linutronix.de, mingo@elte.hu, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] [12/12] GBPAGES: Switch direct mapping setup over to
 set_pte
References: <200802011053.107168490@suse.de> <20080201095325.6419E1B416F@basil.firstfloor.org> <47A358DB.4010602@goop.org> <200802011858.41269.ak@suse.de>
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Andi Kleen wrote:
>> Why?  64-bit Xen will need this to be set_pmd if its an update to L2 of
>> the table.
>>     
>
> Then change_page_attr() and hugepages will already not work because they both 
> do exactly that.
>
> And I didn't want to duplicate this manual code for the GBpages case, so i 
> changed it everywhere to the standard way.

It's a bit moot because Xen doesn't support any kind of large page yet, 
but there has been some work in that area.  The main problem with using 
set_pte is that Xen supports trap'n'emulate for pte-level accesses, but 
not for upper levels.

Looks like you're right about the rest of cpa; may as well make it all 
consistent for now, and we can fix it later when the need arises.

    J
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