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

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

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

 -- Keir

On 3/10/08 00:26, "Dave McCracken" <dcm@xxxxxxxx> wrote:

> 
> This patch enables support of hugepages in a pv Xen environment.  It is
> against the latest xen unstable tree on http://xenbits.xensource.com.
> 
> The patch assumes the guest is passing a physically aligned hugepage.  It does
> reference counting on all the underlying pages.
> 
> Dave McCracken
> Oracle Corp.
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel



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