[PATCH 2/5] vfio/iommufd: Query dirty bitmap before DMA unmap

[Zhenzhong Duan <zhenzhong.duan@intel.com>]

When a existing mapping is unmapped, there could already be dirty bits
which need to be recorded before unmap.

If query dirty bitmap fails, we still need to do unmapping or else there
is stale mapping and it's risky to guest.

Co-developed-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Signed-off-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Tested-by: Xudong Hao <xudong.hao@intel.com>
Tested-by: Giovannio Cabiddu <giovanni.cabiddu@intel.com>
---
 hw/vfio/iommufd.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/hw/vfio/iommufd.c b/hw/vfio/iommufd.c
index b5d6e54c45..0057488ce9 100644
--- a/hw/vfio/iommufd.c
+++ b/hw/vfio/iommufd.c
@@ -73,7 +73,13 @@ static int iommufd_cdev_unmap_one(const VFIOContainerBase *bcontainer,
     if (iotlb && vfio_container_dirty_tracking_is_started(bcontainer)) {
         if (!vfio_container_devices_dirty_tracking_is_supported(bcontainer) &&
             bcontainer->dirty_pages_supported) {
-            /* TODO: query dirty bitmap before DMA unmap */
+            ret = vfio_container_query_dirty_bitmap(bcontainer, iova, size,
+                                                    iotlb->translated_addr,
+                                                    &local_err);
+            if (ret) {
+                error_report_err(local_err);
+            }
+            /* Unmap stale mapping even if query dirty bitmap fails */
             return iommufd_backend_unmap_dma(be, ioas_id, iova, size);
         }
 
-- 
2.47.1