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Re: [Xen-devel] [PATCH 1/2] PV hugepages - Xen patch

To: xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-devel] [PATCH 1/2] PV hugepages - Xen patch
From: Dave McCracken <dcm@xxxxxxxx>
Date: Wed, 8 Oct 2008 12:05:16 -0500
Cc: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
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On Friday 03 October 2008, Keir Fraser wrote:
> Some issues:
>  * You need to check return value of get_page_from_pagenr() on every page
> of the superpage. Any one of them can fail, causing you to undo your work
> so far and then fail.
>  * You need to get_page_type(PGT_writable) on every page if the superpage
> mapping asserts _PAGE_RW. Otherwise the guest is getting write access
> without that being asserted in the reference counts.
>  * Look at get_page_from_l1e() for an example of how this is done for a
> single page. You need to do similar work for every page of the super-page.

Ok, here's a version of the patch with all these issues addressed.

>  * This surely breaks save/restore, since the restore code is not
> superpage-aware.

I don't have this one solved yet.  I'm working on it.

Dave McCracken

Attachment: xen-hpage-05.patch
Description: Text Data

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