Re: [Xen-devel] [PATCH 3/7] xen/mmu: Release the Xen provided L4 (PGD) back.
From: Konrad Rzeszutek Wilk
Date: Fri Jul 27 2012 - 13:42:06 EST
On Fri, Jul 27, 2012 at 12:37:24PM +0100, Stefano Stabellini wrote:
> On Thu, 26 Jul 2012, Konrad Rzeszutek Wilk wrote:
> > Since we are not using it and somebody else could use it.
>
> make sense except it is almost entirely rewritten by the following
> patch...
Yeah, I should squash them.
>
> > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
> > ---
> > arch/x86/xen/mmu.c | 13 +++++++------
> > 1 files changed, 7 insertions(+), 6 deletions(-)
> >
> > diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
> > index a59070b..48bdc9f 100644
> > --- a/arch/x86/xen/mmu.c
> > +++ b/arch/x86/xen/mmu.c
> > @@ -1782,20 +1782,21 @@ void __init xen_setup_kernel_pagetable(pgd_t *pgd, unsigned long max_pfn)
> > /* Unpin Xen-provided one */
> > pin_pagetable_pfn(MMUEXT_UNPIN_TABLE, PFN_DOWN(__pa(pgd)));
> >
> > - /* Switch over */
> > - pgd = init_level4_pgt;
> > -
> > /*
> > * At this stage there can be no user pgd, and no page
> > * structure to attach it to, so make sure we just set kernel
> > * pgd.
> > */
> > xen_mc_batch();
> > - __xen_write_cr3(true, __pa(pgd));
> > + __xen_write_cr3(true, __pa(init_level4_pgt));
> > xen_mc_issue(PARAVIRT_LAZY_CPU);
> >
> > - memblock_reserve(__pa(xen_start_info->pt_base),
> > - xen_start_info->nr_pt_frames * PAGE_SIZE);
> > + /* Offset by one page since the original pgd is going bye bye */
> > + memblock_reserve(__pa(xen_start_info->pt_base + PAGE_SIZE),
> > + (xen_start_info->nr_pt_frames * PAGE_SIZE) - PAGE_SIZE);
> > + /* and also RW it so it can actually be used. */
> > + set_page_prot(pgd, PAGE_KERNEL);
> > + clear_page(pgd);
> > }
> > #else /* !CONFIG_X86_64 */
> > static RESERVE_BRK_ARRAY(pmd_t, initial_kernel_pmd, PTRS_PER_PMD);
> > --
> > 1.7.7.6
> >
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxx
> > http://lists.xen.org/xen-devel
> >
>
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