paravirt: add hooks for ptep_modify_prot_start/commit

This patch adds paravirt-ops hooks in pv_mmu_ops for ptep_modify_prot_start and
ptep_modify_prot_commit.  This allows the hypervisor-specific backends to
implement these in some more efficient way.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 28 insertions, 0 deletions

diff --git a/include/asm-x86/paravirt.h b/include/asm-x86/paravirt.h
index 5ea37a48eecb..e9ada314dfc1 100644
--- a/include/asm-x86/paravirt.h
+++ b/include/asm-x86/paravirt.h
@@ -238,6 +238,11 @@ struct pv_mmu_ops {
         void (*pte_update_defer)(struct mm_struct *mm,
                                  unsigned long addr, pte_t *ptep);
 
+        pte_t (*ptep_modify_prot_start)(struct mm_struct *mm, unsigned long addr,
+                                        pte_t *ptep);
+        void (*ptep_modify_prot_commit)(struct mm_struct *mm, unsigned long addr,
+                                        pte_t *ptep, pte_t pte);
+
         pteval_t (*pte_val)(pte_t);
         pteval_t (*pte_flags)(pte_t);
         pte_t (*make_pte)(pteval_t pte);
@@ -1039,6 +1044,29 @@ static inline pgdval_t pgd_val(pgd_t pgd)
         return ret;
 }
 
+#define  __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION
+static inline pte_t ptep_modify_prot_start(struct mm_struct *mm, unsigned long addr,
+                                           pte_t *ptep)
+{
+        pteval_t ret;
+
+        ret = PVOP_CALL3(pteval_t, pv_mmu_ops.ptep_modify_prot_start,
+                         mm, addr, ptep);
+
+        return (pte_t) { .pte = ret };
+}
+
+static inline void ptep_modify_prot_commit(struct mm_struct *mm, unsigned long addr,
+                                           pte_t *ptep, pte_t pte)
+{
+        if (sizeof(pteval_t) > sizeof(long))
+                /* 5 arg words */
+                pv_mmu_ops.ptep_modify_prot_commit(mm, addr, ptep, pte);
+        else
+                PVOP_VCALL4(pv_mmu_ops.ptep_modify_prot_commit,
+                            mm, addr, ptep, pte.pte);
+}
+
 static inline void set_pte(pte_t *ptep, pte_t pte)
 {
         if (sizeof(pteval_t) > sizeof(long))