From 58b050d2b5dcd57ad4987ad7cc062c0c254d2069 Mon Sep 17 00:00:00 2001
From: Paul Pan <i@0x7f.app>
Date: Sun, 17 Dec 2023 20:18:19 +0800
Subject: [PATCH] feat: quit/reset system by using test device provided by Qemu

---
 src/arch/riscv/board/virt/mod.rs |  1 +
 src/arch/riscv/lowlevel.rs       | 24 +++++++++++++++++++++++-
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/arch/riscv/board/virt/mod.rs b/src/arch/riscv/board/virt/mod.rs
index 7cd41af..38e391f 100644
--- a/src/arch/riscv/board/virt/mod.rs
+++ b/src/arch/riscv/board/virt/mod.rs
@@ -1,5 +1,6 @@
 pub const UART0_BASE: usize = 0x1000_0000;
 pub const UART0_LSR: usize = 0x1000_0005;
+pub const TEST_DEVICE: *mut u32 = 0x10_0000 as *mut u32;
 
 pub mod printer;
 pub mod reader;
diff --git a/src/arch/riscv/lowlevel.rs b/src/arch/riscv/lowlevel.rs
index 2f7b90a..5ea8d84 100644
--- a/src/arch/riscv/lowlevel.rs
+++ b/src/arch/riscv/lowlevel.rs
@@ -1,6 +1,10 @@
-use crate::arch::lowlevel::{Hardware, LowLevel};
 use log::error;
 
+use crate::arch::lowlevel::{Hardware, LowLevel};
+
+#[cfg(feature = "board_virt")]
+use super::board::TEST_DEVICE;
+
 impl LowLevel for Hardware {
     #[inline]
     fn halt() {
@@ -12,9 +16,21 @@ impl LowLevel for Hardware {
         Self::disable_interrupt();
 
         if failure {
+            #[cfg(not(feature = "board_virt"))]
             sbi_rt::system_reset(sbi_rt::Shutdown, sbi_rt::SystemFailure);
+
+            #[cfg(feature = "board_virt")]
+            unsafe {
+                TEST_DEVICE.write_volatile(0x0042_3333)
+            }
         } else {
+            #[cfg(not(feature = "board_virt"))]
             sbi_rt::system_reset(sbi_rt::Shutdown, sbi_rt::NoReason);
+
+            #[cfg(feature = "board_virt")]
+            unsafe {
+                TEST_DEVICE.write_volatile(0x0042_5555)
+            }
         }
 
         loop {
@@ -25,12 +41,18 @@ impl LowLevel for Hardware {
 
     #[inline]
     fn reset(failure: bool) -> ! {
+        #[cfg(not(feature = "board_virt"))]
         if failure {
             sbi_rt::system_reset(sbi_rt::ColdReboot, sbi_rt::SystemFailure);
         } else {
             sbi_rt::system_reset(sbi_rt::WarmReboot, sbi_rt::NoReason);
         }
 
+        #[cfg(feature = "board_virt")]
+        unsafe {
+            TEST_DEVICE.write_volatile(0x0042_7777)
+        }
+
         error!("[riscv/lowlevel] system_reset failed, shutdown instead");
         Self::shutdown(true);
     }