diff --git a/pci/src/vfio.rs b/pci/src/vfio.rs
index 6ece9b124..7b253bcae 100644
--- a/pci/src/vfio.rs
+++ b/pci/src/vfio.rs
@@ -910,26 +910,14 @@ impl PciDevice for VfioPciDevice {
                 let first_bit = region_size.trailing_zeros();
                 region_size = 2u64.pow(first_bit);
 
-                // We need to allocate a guest MMIO address range for that BAR.
-                // In case the BAR is mappable directly, this means it might be
-                // set as user memory region, which expects to deal with 4K
-                // pages. Therefore, the alignment has to be set accordingly.
-                let bar_alignment = if (bar_id == VFIO_PCI_ROM_REGION_INDEX)
-                    || (self.device.get_region_flags(bar_id) & VFIO_REGION_INFO_FLAG_MMAP != 0)
-                {
-                    // 4K alignment
-                    0x1000
-                } else {
-                    // Default 16 bytes alignment
-                    0x10
-                };
+                // BAR allocation needs to be naturally aligned
                 if is_64bit_bar {
                     bar_addr = allocator
-                        .allocate_mmio_addresses(None, region_size, Some(bar_alignment))
+                        .allocate_mmio_addresses(None, region_size, Some(region_size))
                         .ok_or(PciDeviceError::IoAllocationFailed(region_size))?;
                 } else {
                     bar_addr = allocator
-                        .allocate_mmio_hole_addresses(None, region_size, Some(bar_alignment))
+                        .allocate_mmio_hole_addresses(None, region_size, Some(region_size))
                         .ok_or(PciDeviceError::IoAllocationFailed(region_size))?;
                 }
             }