Re: [PATCH] xen: x86/32: perform initial startup oninitial_page_table

[Ian Campbell]

On Wed, 2010-11-24 at 18:19 +0000, Jeremy Fitzhardinge wrote:
> On 11/24/2010 04:09 AM, Ian Campbell wrote:
> > Only make swapper_pg_dir readonly and pinned when generic x86 architecture code
> > (which also starts on initial_page_table) switches to it.  This helps ensure
> > that the generic setup paths work on Xen unmodified. In particular
> > clone_pgd_range writes directly to the destination pgd entries and is used to
> > initialise swapper_pg_dir so we need to ensure that it remains writeable until
> > the last possible moment during bring up.
> >
> > This is complicated slightly by the need to avoid sharing kernel PMD entries
> > when running under Xen, therefore the Xen implementation must make a copy of
> > the kernel PMD (which is otherwise referred to by both intial_page_table and
> > swapper_pg_dir) before switching to swapper_pg_dir.
> 
> The one thing I'd add is the commit ID of the change which made this
> necessary.

Yes, I thought I had but didn't guilt refresh the patch so it didn't
show up.

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