diff --git a/os/src/boards/qemu.rs b/os/src/boards/qemu.rs
index 16dfb40..92d4f37 100644
--- a/os/src/boards/qemu.rs
+++ b/os/src/boards/qemu.rs
@@ -1,10 +1,10 @@
 pub const CLOCK_FREQ: usize = 12500000;
 
 pub const MMIO: &[(usize, usize)] = &[
-    (0x1000_0000, 0xa000), // VIRT_UART0 in virt machine
-    //    (0x1000_1000, 0x9000),    // VIRT_VIRTIO with GPU in virt machine
-    (0x0C00_0000, 0x40_0000), // VIRT_PLIC in virt machine
-    (0x0010_0000, 0x00_2000), // VIRT_TEST/RTC  in virt machine
+//    (0x0010_0000, 0x00_2000), // VIRT_TEST/RTC  in virt machine
+    (0x2000000, 0x10000),
+    (0xc000000, 0x210000), // VIRT_PLIC in virt machine
+    (0x10000000, 0x9000), // VIRT_UART0 with GPU  in virt machine
 ];
 
 pub type BlockDeviceImpl = crate::drivers::block::VirtIOBlock;
diff --git a/os/src/config.rs b/os/src/config.rs
index 41fe977..8f8b709 100644
--- a/os/src/config.rs
+++ b/os/src/config.rs
@@ -2,8 +2,8 @@
 
 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 KERNEL_HEAP_SIZE: usize = 0x100_0000;
+pub const MEMORY_END: usize = 0x88000000;
 pub const PAGE_SIZE: usize = 0x1000;
 pub const PAGE_SIZE_BITS: usize = 0xc;
 
diff --git a/os/src/main.rs b/os/src/main.rs
index ff6cf3a..e328e8e 100644
--- a/os/src/main.rs
+++ b/os/src/main.rs
@@ -32,6 +32,8 @@ mod task;
 mod timer;
 mod trap;
 
+use syscall::create_desktop;
+
 core::arch::global_asm!(include_str!("entry.asm"));
 
 fn clear_bss() {
@@ -69,6 +71,7 @@ pub fn rust_main() -> ! {
     timer::set_next_trigger();
     board::device_init();
     fs::list_apps();
+    syscall::create_desktop();
     task::add_initproc();
     *DEV_NON_BLOCKING_ACCESS.exclusive_access() = true;
     task::run_tasks();
diff --git a/os/src/syscall/gui.rs b/os/src/syscall/gui.rs
index b5ac9fb..9ca7f45 100644
--- a/os/src/syscall/gui.rs
+++ b/os/src/syscall/gui.rs
@@ -1,7 +1,14 @@
-use alloc::{sync::Arc, vec::{Vec, }, string::ToString};
-use embedded_graphics::{prelude::{Point, Size}, primitives::arc};
+use alloc::{string::ToString, sync::Arc, vec::Vec};
+use embedded_graphics::{
+    prelude::{Point, Size},
+    primitives::arc,
+};
 
-use crate::{gui::{Component, Panel, ImageComp, IconController, Terminal, Button}, fs::ROOT_INODE, sync::UPIntrFreeCell};
+use crate::{
+    fs::ROOT_INODE,
+    gui::{Button, Component, IconController, ImageComp, Panel, Terminal},
+    sync::UPIntrFreeCell,
+};
 
 static DT: &[u8] = include_bytes!("../assert/desktop.bmp");
 
@@ -15,8 +22,9 @@ lazy_static::lazy_static!(
 );
 
 pub fn create_desktop() -> isize {
-    let mut p:Arc<dyn Component + 'static> = Arc::new(Panel::new(Size::new(1024, 768), Point::new(0, 0)));
-    let image = ImageComp::new(Size::new(1024, 768),Point::new(0, 0),DT,Some(p.clone()));
+    let mut p: Arc<dyn Component + 'static> =
+        Arc::new(Panel::new(Size::new(1024, 768), Point::new(0, 0)));
+    let image = ImageComp::new(Size::new(1024, 768), Point::new(0, 0), DT, Some(p.clone()));
     let icon = IconController::new(ROOT_INODE.ls(), Some(p.clone()));
     p.add(Arc::new(image));
     p.add(Arc::new(icon));
@@ -30,17 +38,20 @@ pub fn create_desktop() -> isize {
 
 pub fn create_terminal() {
     let desktop = DESKTOP.exclusive_access();
-    let arc_t = Arc::new(
-        Terminal::new(
-            Size::new(400, 400), 
-            Point::new(200, 100), 
-            Some(desktop.clone()), 
-            Some("demo.txt".to_string()),
-            "".to_string()
-        )
-    );
+    let arc_t = Arc::new(Terminal::new(
+        Size::new(400, 400),
+        Point::new(200, 100),
+        Some(desktop.clone()),
+        Some("demo.txt".to_string()),
+        "".to_string(),
+    ));
     let text = Panel::new(Size::new(400, 400), Point::new(200, 100));
-    let button = Button::new(Size::new(20, 20), Point::new(370, 10), Some(arc_t.clone()), "X".to_string());
+    let button = Button::new(
+        Size::new(20, 20),
+        Point::new(370, 10),
+        Some(arc_t.clone()),
+        "X".to_string(),
+    );
     arc_t.add(Arc::new(text));
     arc_t.add(Arc::new(button));
     arc_t.paint();
@@ -48,4 +59,3 @@ pub fn create_terminal() {
     let mut pad = PAD.exclusive_access();
     *pad = Some(arc_t);
 }
-
diff --git a/os/src/syscall/mod.rs b/os/src/syscall/mod.rs
index df2328a..46890ed 100644
--- a/os/src/syscall/mod.rs
+++ b/os/src/syscall/mod.rs
@@ -25,7 +25,7 @@ const SYSCALL_SEMAPHORE_DOWN: usize = 1022;
 const SYSCALL_CONDVAR_CREATE: usize = 1030;
 const SYSCALL_CONDVAR_SIGNAL: usize = 1031;
 const SYSCALL_CONDVAR_WAIT: usize = 1032;
-
+const SYSCALL_CREATE_DESKTOP: usize = 2000;
 mod fs;
 mod process;
 mod sync;
@@ -37,6 +37,7 @@ use process::*;
 use sync::*;
 use thread::*;
 pub use gui::PAD;
+pub use self::gui::create_desktop;
 
 pub fn syscall(syscall_id: usize, args: [usize; 3]) -> isize {
     match syscall_id {
@@ -67,6 +68,7 @@ pub fn syscall(syscall_id: usize, args: [usize; 3]) -> isize {
         SYSCALL_CONDVAR_CREATE => sys_condvar_create(args[0]),
         SYSCALL_CONDVAR_SIGNAL => sys_condvar_signal(args[0]),
         SYSCALL_CONDVAR_WAIT => sys_condvar_wait(args[0], args[1]),
+        SYSCALL_CREATE_DESKTOP => create_desktop(),
         _ => panic!("Unsupported syscall_id: {}", syscall_id),
     }
 }