minimal KVM abstraction + real mode guest example

1 files changed, 39 insertions, 0 deletions

diff --git a/src/kvm.rs b/src/kvm.rs
new file mode 100644
index 0000000..3522adc
--- /dev/null
+++ b/src/kvm.rs
@@ -0,0 +1,39 @@
+use std::fs;
+use std::io;
+use std::os::unix::io::FromRawFd;
+
+use crate::{libcret, ioctl, kvm_sys};
+use crate::vm::Vm;
+
+pub struct Kvm {
+    kvm: fs::File,
+}
+
+impl Kvm {
+    pub fn new() -> io::Result<Kvm> {
+        let kvm = libcret(unsafe {
+            libc::open("/dev/kvm\0".as_ptr().cast(), libc::O_RDWR | libc::O_CLOEXEC)
+        })
+        .map(|fd| unsafe { fs::File::from_raw_fd(fd) })?;
+
+        assert_eq!(
+            kvm_sys::KVM_API_VERSION,
+            ioctl(&kvm, kvm_sys::KVM_GET_API_VERSION, 0)?
+        );
+
+        Ok(Kvm { kvm })
+    }
+
+    fn get_vpcu_mmap_size(&self) -> io::Result<usize> {
+        ioctl(&self.kvm, kvm_sys::KVM_GET_VCPU_MMAP_SIZE, 0).map(|size| size as usize)
+    }
+
+    pub fn create_vm(&self) -> io::Result<Vm> {
+        let vm = ioctl(&self.kvm, kvm_sys::KVM_CREATE_VM, 0 /* machine id */)
+            .map(|fd| unsafe { fs::File::from_raw_fd(fd) })?;
+
+        let vcpu_mmap_size = self.get_vpcu_mmap_size()?;
+
+        Ok(Vm::new(vm, vcpu_mmap_size))
+    }
+}