It is pointless to overlap a memory subregion with priority 0.
Use the simpler memory_region_add_subregion() function.

This patch was produced with the following spatch script:

    @@
    expression region;
    expression offset;
    expression subregion;
    @@
    -memory_region_add_subregion_overlap(region, offset, subregion, 0)
    +memory_region_add_subregion(region, offset, subregion)

Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
---
 hw/vfio/pci.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
index 2d40b396f2..74b1eb7ddc 100644
--- a/hw/vfio/pci.c
+++ b/hw/vfio/pci.c
@@ -1095,8 +1095,7 @@ static void vfio_sub_page_bar_update_mapping(PCIDevice *pdev, int bar)
     memory_region_set_size(mmap_mr, size);
     if (size != vdev->bars[bar].size && memory_region_is_mapped(base_mr)) {
         memory_region_del_subregion(r->address_space, base_mr);
-        memory_region_add_subregion_overlap(r->address_space,
-                                            bar_addr, base_mr, 0);
+        memory_region_add_subregion(r->address_space, bar_addr, base_mr);
     }
 
     memory_region_transaction_commit();
-- 
2.21.0