diff --git a/os/src/boards/qemu.rs b/os/src/boards/qemu.rs
index 9740646cf..275de4d22 100644
--- a/os/src/boards/qemu.rs
+++ b/os/src/boards/qemu.rs
@@ -1,5 +1,5 @@
 pub const CLOCK_FREQ: usize = 12500000;
-//pub const MEMORY_END: usize = 0x801000000;
+pub const MEMORY_END: usize = 0x8800_0000;
 
 pub const MMIO: &[(usize, usize)] = &[
     (0x0010_0000, 0x00_2000), // VIRT_TEST/RTC  in virt machine
diff --git a/os/src/config.rs b/os/src/config.rs
index 41fe977c2..446a874f3 100644
--- a/os/src/config.rs
+++ b/os/src/config.rs
@@ -3,11 +3,10 @@
 pub const USER_STACK_SIZE: usize = 4096 * 2;
 pub const KERNEL_STACK_SIZE: usize = 4096 * 2;
 pub const KERNEL_HEAP_SIZE: usize = 0x20_0000;
-pub const MEMORY_END: usize = 0x80800000;
 pub const PAGE_SIZE: usize = 0x1000;
 pub const PAGE_SIZE_BITS: usize = 0xc;
 
 pub const TRAMPOLINE: usize = usize::MAX - PAGE_SIZE + 1;
 pub const TRAP_CONTEXT_BASE: usize = TRAMPOLINE - PAGE_SIZE;
 
-pub use crate::board::{CLOCK_FREQ, MMIO};
+pub use crate::board::{CLOCK_FREQ, MEMORY_END, MMIO};