1 files changed, 8 insertions, 5 deletions

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index bfb1b6de0584..5dee3024579d 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -803,11 +803,14 @@ static int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
         if (copy_to_user(log->dirty_bitmap, memslot->dirty_bitmap, n))
                 goto out;
 
-        mutex_lock(&kvm->lock);
-        kvm_mmu_slot_remove_write_access(kvm, log->slot);
-        kvm_flush_remote_tlbs(kvm);
-        memset(memslot->dirty_bitmap, 0, n);
-        mutex_unlock(&kvm->lock);
+        /* If nothing is dirty, don't bother messing with page tables. */
+        if (any) {
+                mutex_lock(&kvm->lock);
+                kvm_mmu_slot_remove_write_access(kvm, log->slot);
+                kvm_flush_remote_tlbs(kvm);
+                memset(memslot->dirty_bitmap, 0, n);
+                mutex_unlock(&kvm->lock);
+        }
 
         r = 0;