From 0cf622d38806c9465aed729c36554b9e7475fd22 Mon Sep 17 00:00:00 2001
From: Masato Imai <mii@sfc.wide.ad.jp>
Date: Mon, 4 Aug 2025 08:15:38 +0000
Subject: [PATCH] error

---
 nel_os_kernel/src/main.rs                   |  2 +-
 nel_os_kernel/src/vmm/mod.rs                | 11 ++++++----
 nel_os_kernel/src/vmm/x86_64/amd/mod.rs     | 19 +++++++++--------
 nel_os_kernel/src/vmm/x86_64/intel/mod.rs   | 23 ++++++++++++---------
 nel_os_kernel/src/vmm/x86_64/intel/vmxon.rs | 16 ++++++++++++++
 5 files changed, 47 insertions(+), 24 deletions(-)
 create mode 100644 nel_os_kernel/src/vmm/x86_64/intel/vmxon.rs

diff --git a/nel_os_kernel/src/main.rs b/nel_os_kernel/src/main.rs
index 8c60712..968295a 100644
--- a/nel_os_kernel/src/main.rs
+++ b/nel_os_kernel/src/main.rs
@@ -157,7 +157,7 @@ pub extern "sysv64" fn main(boot_info: &nel_os_common::BootInfo) {
 
     info!("Interrupts enabled");
 
-    let mut vcpu = vmm::get_vcpu();
+    let mut vcpu = vmm::get_vcpu().unwrap();
     vcpu.run();
 
     hlt_loop();
diff --git a/nel_os_kernel/src/vmm/mod.rs b/nel_os_kernel/src/vmm/mod.rs
index 16cbcd2..964fb44 100644
--- a/nel_os_kernel/src/vmm/mod.rs
+++ b/nel_os_kernel/src/vmm/mod.rs
@@ -8,18 +8,21 @@ use crate::{
 pub mod x86_64;
 
 pub trait VCpu {
+    fn new() -> Result<Self, &'static str>
+    where
+        Self: Sized;
     fn is_supported() -> bool
     where
         Self: Sized;
     fn run(&mut self);
 }
 
-pub fn get_vcpu() -> Box<dyn VCpu> {
+pub fn get_vcpu() -> Result<Box<dyn VCpu>, &'static str> {
     if platform::is_amd() && AMDVCpu::is_supported() {
-        Box::new(AMDVCpu::new())
+        Ok(Box::new(AMDVCpu::new()?))
     } else if platform::is_intel() && IntelVCpu::is_supported() {
-        Box::new(IntelVCpu::new())
+        Ok(Box::new(IntelVCpu::new()?))
     } else {
-        panic!("Unsupported CPU architecture");
+        Err("Unsupported CPU architecture")
     }
 }
diff --git a/nel_os_kernel/src/vmm/x86_64/amd/mod.rs b/nel_os_kernel/src/vmm/x86_64/amd/mod.rs
index 49c5ffb..ef9d03a 100644
--- a/nel_os_kernel/src/vmm/x86_64/amd/mod.rs
+++ b/nel_os_kernel/src/vmm/x86_64/amd/mod.rs
@@ -7,19 +7,20 @@ use crate::{
 
 pub struct AMDVCpu;
 
-impl AMDVCpu {
-    pub fn new() -> Self {
+impl VCpu for AMDVCpu {
+    fn run(&mut self) {
+        info!("VCpu on AMD");
+    }
+
+    fn new() -> Result<Self, &'static str>
+    where
+        Self: Sized,
+    {
         let mut efer = common::read_msr(0xc000_0080);
         efer |= 1 << 12;
         common::write_msr(0xc000_0080, efer);
 
-        AMDVCpu
-    }
-}
-
-impl VCpu for AMDVCpu {
-    fn run(&mut self) {
-        info!("VCpu on AMD");
+        Ok(AMDVCpu)
     }
 
     fn is_supported() -> bool
diff --git a/nel_os_kernel/src/vmm/x86_64/intel/mod.rs b/nel_os_kernel/src/vmm/x86_64/intel/mod.rs
index bac57b5..aae0493 100644
--- a/nel_os_kernel/src/vmm/x86_64/intel/mod.rs
+++ b/nel_os_kernel/src/vmm/x86_64/intel/mod.rs
@@ -1,3 +1,5 @@
+mod vmxon;
+
 use raw_cpuid::cpuid;
 
 use crate::{
@@ -7,8 +9,15 @@ use crate::{
 
 pub struct IntelVCpu;
 
-impl IntelVCpu {
-    pub fn new() -> Self {
+impl VCpu for IntelVCpu {
+    fn run(&mut self) {
+        info!("VCpu on Intel");
+    }
+
+    fn new() -> Result<Self, &'static str>
+    where
+        Self: Sized,
+    {
         let mut msr = common::read_msr(0x3a);
         if msr & (1 << 2) == 0 {
             msr |= 1 << 2;
@@ -18,16 +27,10 @@ impl IntelVCpu {
 
         let msr = common::read_msr(0x3a);
         if msr & (1 << 2) == 0 {
-            panic!("VMX is not enabled in the BIOS");
+            return Err("VMX is not enabled in the BIOS");
         }
 
-        IntelVCpu
-    }
-}
-
-impl VCpu for IntelVCpu {
-    fn run(&mut self) {
-        info!("VCpu on Intel");
+        Ok(IntelVCpu)
     }
 
     fn is_supported() -> bool
diff --git a/nel_os_kernel/src/vmm/x86_64/intel/vmxon.rs b/nel_os_kernel/src/vmm/x86_64/intel/vmxon.rs
new file mode 100644
index 0000000..0feaee9
--- /dev/null
+++ b/nel_os_kernel/src/vmm/x86_64/intel/vmxon.rs
@@ -0,0 +1,16 @@
+use x86_64::structures::paging::{FrameAllocator, PhysFrame, Size4KiB};
+
+#[repr(C, align(4096))]
+pub struct Vmxon {
+    frame: PhysFrame,
+}
+
+impl Vmxon {
+    pub fn new(frame_allocator: &mut impl FrameAllocator<Size4KiB>) -> Result<Self, &'static str> {
+        let frame = frame_allocator
+            .allocate_frame()
+            .ok_or("Failed to allocate frame for VMXON")?;
+
+        Ok(Vmxon { frame })
+    }
+}