diff --git a/xen/drivers/vpci/vpci.c b/xen/drivers/vpci/vpci.c
index 657697fe34..fb0947179b 100644
--- a/xen/drivers/vpci/vpci.c
+++ b/xen/drivers/vpci/vpci.c
@@ -370,6 +370,7 @@ uint32_t vpci_read(pci_sbdf_t sbdf, unsigned int reg, unsigned int size)
             break;
         ASSERT(data_offset < size);
     }
+    spin_unlock(&pdev->vpci->lock);
 
     if ( data_offset < size )
     {
@@ -379,7 +380,6 @@ uint32_t vpci_read(pci_sbdf_t sbdf, unsigned int reg, unsigned int size)
 
         data = merge_result(data, tmp_data, size - data_offset, data_offset);
     }
-    spin_unlock(&pdev->vpci->lock);
 
     return data & (0xffffffff >> (32 - 8 * size));
 }
@@ -475,13 +475,12 @@ void vpci_write(pci_sbdf_t sbdf, unsigned int reg, unsigned int size,
             break;
         ASSERT(data_offset < size);
     }
+    spin_unlock(&pdev->vpci->lock);
 
     if ( data_offset < size )
         /* Tailing gap, write the remaining. */
         vpci_write_hw(sbdf, reg + data_offset, size - data_offset,
                       data >> (data_offset * 8));
-
-    spin_unlock(&pdev->vpci->lock);
 }
 
 /* Helper function to check an access size and alignment on vpci space. */