[PATCH v2 2/4] kvm: Synchronize the backup bitmap in the last stage

[Gavin Shan <gshan@redhat.com>]

In the last stage of live migration or memory slot removal, the
backup bitmap needs to be synchronized when it has been enabled.

Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Tested-by: Zhenyu Zhang <zhenyzha@redhat.com>
---
 accel/kvm/kvm-all.c      | 11 +++++++++++
 include/sysemu/kvm_int.h |  1 +
 2 files changed, 12 insertions(+)

diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
index 01a6a026af..b5e12de522 100644
--- a/accel/kvm/kvm-all.c
+++ b/accel/kvm/kvm-all.c
@@ -1352,6 +1352,10 @@ static void kvm_set_phys_mem(KVMMemoryListener *kml,
                  */
                 if (kvm_state->kvm_dirty_ring_size) {
                     kvm_dirty_ring_reap_locked(kvm_state, NULL);
+                    if (kvm_state->kvm_dirty_ring_with_bitmap) {
+                        kvm_slot_sync_dirty_pages(mem);
+                        kvm_slot_get_dirty_log(kvm_state, mem);
+                    }
                 } else {
                     kvm_slot_get_dirty_log(kvm_state, mem);
                 }
@@ -1573,6 +1577,12 @@ static void kvm_log_sync_global(MemoryListener *l, bool last_stage)
         mem = &kml->slots[i];
         if (mem->memory_size && mem->flags & KVM_MEM_LOG_DIRTY_PAGES) {
             kvm_slot_sync_dirty_pages(mem);
+
+            if (s->kvm_dirty_ring_with_bitmap && last_stage &&
+                kvm_slot_get_dirty_log(s, mem)) {
+                kvm_slot_sync_dirty_pages(mem);
+            }
+
             /*
              * This is not needed by KVM_GET_DIRTY_LOG because the
              * ioctl will unconditionally overwrite the whole region.
@@ -3701,6 +3711,7 @@ static void kvm_accel_instance_init(Object *obj)
     s->kernel_irqchip_split = ON_OFF_AUTO_AUTO;
     /* KVM dirty ring is by default off */
     s->kvm_dirty_ring_size = 0;
+    s->kvm_dirty_ring_with_bitmap = false;
     s->notify_vmexit = NOTIFY_VMEXIT_OPTION_RUN;
     s->notify_window = 0;
 }
diff --git a/include/sysemu/kvm_int.h b/include/sysemu/kvm_int.h
index 60b520a13e..fdd5b1bde0 100644
--- a/include/sysemu/kvm_int.h
+++ b/include/sysemu/kvm_int.h
@@ -115,6 +115,7 @@ struct KVMState
     } *as;
     uint64_t kvm_dirty_ring_bytes;  /* Size of the per-vcpu dirty ring */
     uint32_t kvm_dirty_ring_size;   /* Number of dirty GFNs per ring */
+    bool kvm_dirty_ring_with_bitmap;
     struct KVMDirtyRingReaper reaper;
     NotifyVmexitOption notify_vmexit;
     uint32_t notify_window;
-- 
2.23.0