KVM: add support for change_pte mmu notifiers

this is needed for kvm if it want ksm to directly map pages into its
shadow page tables.

[marcelo: cast pfn assignment to u64]

Signed-off-by: Izik Eidus <ieidus@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

1 files changed, 14 insertions, 0 deletions

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index e79c54034bcd..b7c78a403dc2 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -850,6 +850,19 @@ static void kvm_mmu_notifier_invalidate_page(struct mmu_notifier *mn,
 
 }
 
+static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn,
+                                        struct mm_struct *mm,
+                                        unsigned long address,
+                                        pte_t pte)
+{
+        struct kvm *kvm = mmu_notifier_to_kvm(mn);
+
+        spin_lock(&kvm->mmu_lock);
+        kvm->mmu_notifier_seq++;
+        kvm_set_spte_hva(kvm, address, pte);
+        spin_unlock(&kvm->mmu_lock);
+}
+
 static void kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
                                                     struct mm_struct *mm,
                                                     unsigned long start,
@@ -929,6 +942,7 @@ static const struct mmu_notifier_ops kvm_mmu_notifier_ops = {
         .invalidate_range_start = kvm_mmu_notifier_invalidate_range_start,
         .invalidate_range_end   = kvm_mmu_notifier_invalidate_range_end,
         .clear_flush_young      = kvm_mmu_notifier_clear_flush_young,
+        .change_pte             = kvm_mmu_notifier_change_pte,
         .release                = kvm_mmu_notifier_release,
 };
 #endif /* CONFIG_MMU_NOTIFIER && KVM_ARCH_WANT_MMU_NOTIFIER */