rustsbi: H ext should be enabled by rv64,x-h=true

Author: luojia65

README.md

@@ -95,6 +95,18 @@ test run_test_kernel ... ok
 test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 2.31s
 ```
 
+## Notes
+
+1. How to enable hypervisor H extension on QEMU?
+
+You should use these following line of parameters:
+
+```rust
+    command.args(&["-cpu", "rv64,x-h=true"]);
+```
+
+... to enable H extension on QEMU software.
+
 ## License 
 
 This project is licensed under Mulan PSL v2.

rustsbi-qemu/src/main.rs

@@ -81,11 +81,6 @@ extern "C" fn rust_main(hartid: usize, opqaue: usize) -> ! {
     unsafe {
         // enable wake by ipi
         riscv::register::mstatus::set_mie();
-        // enable H extension
-        asm!(
-            "csrr {val}, misa", "li {h}, 0x80", "or {val}, {val}, {h}", "csrw misa, {val}",
-            val = lateout(reg) _, h = lateout(reg) _
-        );
     }
     if hartid == 0 {
         // print hart csr configuration