2 files changed, 50 insertions, 3 deletions

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index b767ec97368a..346a3478dd00 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -11,6 +11,7 @@
  *               Christian Borntraeger <borntraeger@de.ibm.com>
  *               Heiko Carstens <heiko.carstens@de.ibm.com>
  *               Christian Ehrhardt <ehrhardt@de.ibm.com>
+ *               Jason J. Herne <jjherne@us.ibm.com>
  */
 
 #include <linux/compiler.h>
@@ -179,6 +180,25 @@ int kvm_dev_ioctl_check_extension(long ext)
         return r;
 }
 
+static void kvm_s390_sync_dirty_log(struct kvm *kvm,
+                                        struct kvm_memory_slot *memslot)
+{
+        gfn_t cur_gfn, last_gfn;
+        unsigned long address;
+        struct gmap *gmap = kvm->arch.gmap;
+
+        down_read(&gmap->mm->mmap_sem);
+        /* Loop over all guest pages */
+        last_gfn = memslot->base_gfn + memslot->npages;
+        for (cur_gfn = memslot->base_gfn; cur_gfn <= last_gfn; cur_gfn++) {
+                address = gfn_to_hva_memslot(memslot, cur_gfn);
+
+                if (gmap_test_and_clear_dirty(address, gmap))
+                        mark_page_dirty(kvm, cur_gfn);
+        }
+        up_read(&gmap->mm->mmap_sem);
+}
+
 /* Section: vm related */
 /*
  * Get (and clear) the dirty memory log for a memory slot.
@@ -186,7 +206,36 @@ int kvm_dev_ioctl_check_extension(long ext)
 int kvm_vm_ioctl_get_dirty_log(struct kvm *kvm,
                                struct kvm_dirty_log *log)
 {
-        return 0;
+        int r;
+        unsigned long n;
+        struct kvm_memory_slot *memslot;
+        int is_dirty = 0;
+
+        mutex_lock(&kvm->slots_lock);
+
+        r = -EINVAL;
+        if (log->slot >= KVM_USER_MEM_SLOTS)
+                goto out;
+
+        memslot = id_to_memslot(kvm->memslots, log->slot);
+        r = -ENOENT;
+        if (!memslot->dirty_bitmap)
+                goto out;
+
+        kvm_s390_sync_dirty_log(kvm, memslot);
+        r = kvm_get_dirty_log(kvm, log, &is_dirty);
+        if (r)
+                goto out;
+
+        /* Clear the dirty log */
+        if (is_dirty) {
+                n = kvm_dirty_bitmap_bytes(memslot);
+                memset(memslot->dirty_bitmap, 0, n);
+        }
+        r = 0;
+out:
+        mutex_unlock(&kvm->slots_lock);
+        return r;
 }
 
 static int kvm_vm_ioctl_enable_cap(struct kvm *kvm, struct kvm_enable_cap *cap)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 56baae8c2f56..7facdb1f1374 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -637,14 +637,12 @@ static int kvm_vm_release(struct inode *inode, struct file *filp)
  */
 static int kvm_create_dirty_bitmap(struct kvm_memory_slot *memslot)
 {
-#ifndef CONFIG_S390
         unsigned long dirty_bytes = 2 * kvm_dirty_bitmap_bytes(memslot);
 
         memslot->dirty_bitmap = kvm_kvzalloc(dirty_bytes);
         if (!memslot->dirty_bitmap)
                 return -ENOMEM;
 
-#endif /* !CONFIG_S390 */
         return 0;
 }