5 files changed, 38 insertions, 6 deletions

diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index e9b504537212..78c9a1b9e6b0 100644
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -30,6 +30,7 @@
 #include <asm/setup.h>
 #include <asm/arch_hooks.h>
 #include <asm/time.h>
+#include <asm/pgalloc.h>
 #include <asm/irq.h>
 #include <asm/delay.h>
 #include <asm/fixmap.h>
@@ -366,6 +367,9 @@ struct pv_mmu_ops pv_mmu_ops = {
         .flush_tlb_single = native_flush_tlb_single,
         .flush_tlb_others = native_flush_tlb_others,
 
+        .pgd_alloc = __paravirt_pgd_alloc,
+        .pgd_free = paravirt_nop,
+
         .alloc_pte = paravirt_nop,
         .alloc_pmd = paravirt_nop,
         .alloc_pmd_clone = paravirt_nop,
diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index 45b99ac39480..418c4432fb39 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -215,13 +215,15 @@ pgd_t *pgd_alloc(struct mm_struct *mm)
 
         /* so that alloc_pmd can use it */
         mm->pgd = pgd;
-        if (pgd)
+        if (pgd) {
                 pgd_ctor(pgd);
 
-        if (pgd && !pgd_prepopulate_pmd(mm, pgd)) {
-                pgd_dtor(pgd);
-                free_page((unsigned long)pgd);
-                pgd = NULL;
+                if (paravirt_pgd_alloc(mm) != 0 ||
+                    !pgd_prepopulate_pmd(mm, pgd)) {
+                        pgd_dtor(pgd);
+                        free_page((unsigned long)pgd);
+                        pgd = NULL;
+                }
         }
 
         return pgd;
@@ -231,6 +233,7 @@ void pgd_free(struct mm_struct *mm, pgd_t *pgd)
 {
         pgd_mop_up_pmds(mm, pgd);
         pgd_dtor(pgd);
+        paravirt_pgd_free(mm, pgd);
         free_page((unsigned long)pgd);
 }
 
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 76ad1efaf09e..d62f14e20708 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -45,6 +45,7 @@
 #include <asm/pgtable.h>
 #include <asm/tlbflush.h>
 #include <asm/reboot.h>
+#include <asm/pgalloc.h>
 
 #include "xen-ops.h"
 #include "mmu.h"
@@ -1153,6 +1154,9 @@ static const struct pv_mmu_ops xen_mmu_ops __initdata = {
         .pte_update = paravirt_nop,
         .pte_update_defer = paravirt_nop,
 
+        .pgd_alloc = __paravirt_pgd_alloc,
+        .pgd_free = paravirt_nop,
+
         .alloc_pte = xen_alloc_pte_init,
         .release_pte = xen_release_pte_init,
         .alloc_pmd = xen_alloc_pte_init,
diff --git a/include/asm-x86/paravirt.h b/include/asm-x86/paravirt.h
index 41f5447efd88..5467e2cff4bc 100644
--- a/include/asm-x86/paravirt.h
+++ b/include/asm-x86/paravirt.h
@@ -219,7 +219,14 @@ struct pv_mmu_ops {
         void (*flush_tlb_others)(const cpumask_t *cpus, struct mm_struct *mm,
                                  unsigned long va);
 
-        /* Hooks for allocating/releasing pagetable pages */
+        /* Hooks for allocating and freeing a pagetable top-level */
+        int  (*pgd_alloc)(struct mm_struct *mm);
+        void (*pgd_free)(struct mm_struct *mm, pgd_t *pgd);
+
+        /*
+         * Hooks for allocating/releasing pagetable pages when they're
+         * attached to a pagetable
+         */
         void (*alloc_pte)(struct mm_struct *mm, u32 pfn);
         void (*alloc_pmd)(struct mm_struct *mm, u32 pfn);
         void (*alloc_pmd_clone)(u32 pfn, u32 clonepfn, u32 start, u32 count);
@@ -925,6 +932,16 @@ static inline void flush_tlb_others(cpumask_t cpumask, struct mm_struct *mm,
         PVOP_VCALL3(pv_mmu_ops.flush_tlb_others, &cpumask, mm, va);
 }
 
+static inline int paravirt_pgd_alloc(struct mm_struct *mm)
+{
+        return PVOP_CALL1(int, pv_mmu_ops.pgd_alloc, mm);
+}
+
+static inline void paravirt_pgd_free(struct mm_struct *mm, pgd_t *pgd)
+{
+        PVOP_VCALL2(pv_mmu_ops.pgd_free, mm, pgd);
+}
+
 static inline void paravirt_alloc_pte(struct mm_struct *mm, unsigned pfn)
 {
         PVOP_VCALL2(pv_mmu_ops.alloc_pte, mm, pfn);
diff --git a/include/asm-x86/pgalloc.h b/include/asm-x86/pgalloc.h
index 91e4641f3f31..d63ea431cb3b 100644
--- a/include/asm-x86/pgalloc.h
+++ b/include/asm-x86/pgalloc.h
@@ -5,9 +5,13 @@
 #include <linux/mm.h>           /* for struct page */
 #include <linux/pagemap.h>
 
+static inline int  __paravirt_pgd_alloc(struct mm_struct *mm) { return 0; }
+
 #ifdef CONFIG_PARAVIRT
 #include <asm/paravirt.h>
 #else
+#define paravirt_pgd_alloc(mm)  __paravirt_pgd_alloc(mm)
+static inline void paravirt_pgd_free(struct mm_struct *mm, pgd_t *pgd) {}
 static inline void paravirt_alloc_pte(struct mm_struct *mm, unsigned long pfn)  {}
 static inline void paravirt_alloc_pmd(struct mm_struct *mm, unsigned long pfn)  {}
 static inline void paravirt_alloc_pmd_clone(unsigned long pfn, unsigned long clonepfn,