1 files changed, 31 insertions, 0 deletions

diff --git a/drivers/kvm/x86.c b/drivers/kvm/x86.c
index 9618fcba887e..935e2769b787 100644
--- a/drivers/kvm/x86.c
+++ b/drivers/kvm/x86.c
@@ -937,6 +937,37 @@ static int kvm_vm_ioctl_set_irqchip(struct kvm *kvm, struct kvm_irqchip *chip)
         return r;
 }
 
+/*
+ * Get (and clear) the dirty memory log for a memory slot.
+ */
+int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
+                                      struct kvm_dirty_log *log)
+{
+        int r;
+        int n;
+        struct kvm_memory_slot *memslot;
+        int is_dirty = 0;
+
+        mutex_lock(&kvm->lock);
+
+        r = kvm_get_dirty_log(kvm, log, &is_dirty);
+        if (r)
+                goto out;
+
+        /* If nothing is dirty, don't bother messing with page tables. */
+        if (is_dirty) {
+                kvm_mmu_slot_remove_write_access(kvm, log->slot);
+                kvm_flush_remote_tlbs(kvm);
+                memslot = &kvm->memslots[log->slot];
+                n = ALIGN(memslot->npages, BITS_PER_LONG) / 8;
+                memset(memslot->dirty_bitmap, 0, n);
+        }
+        r = 0;
+out:
+        mutex_unlock(&kvm->lock);
+        return r;
+}
+
 long kvm_arch_vm_ioctl(struct file *filp,
                        unsigned int ioctl, unsigned long arg)
 {