x86: xen unify x86 add common mm pgtable c fix

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 18 insertions, 0 deletions

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index d526b46ae188..ed16b7704a3c 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -200,6 +200,24 @@ static int pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd)
 
         return 1;
 }
+
+void pud_populate(struct mm_struct *mm, pud_t *pudp, pmd_t *pmd)
+{
+        paravirt_alloc_pd(mm, __pa(pmd) >> PAGE_SHIFT);
+
+        /* Note: almost everything apart from _PAGE_PRESENT is
+           reserved at the pmd (PDPT) level. */
+        set_pud(pudp, __pud(__pa(pmd) | _PAGE_PRESENT));
+
+        /*
+         * According to Intel App note "TLBs, Paging-Structure Caches,
+         * and Their Invalidation", April 2007, document 317080-001,
+         * section 8.1: in PAE mode we explicitly have to flush the
+         * TLB via cr3 if the top-level pgd is changed...
+         */
+        if (mm == current->active_mm)
+                write_cr3(read_cr3());
+}
 #else  /* !CONFIG_X86_PAE */
 /* No need to prepopulate any pagetable entries in non-PAE modes. */
 static int pgd_prepopulate_pmd(struct mm_struct *mm, pgd_t *pgd)