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    SubjectRe: [Xen-devel] [PATCH 3/7] xen/mmu: Release the Xen provided L4 (PGD) back.
    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...

    > Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
    > ---
    > 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@lists.xen.org
    > http://lists.xen.org/xen-devel
    >


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