feat(hvf): create and destroy guests

Signed-off-by: Changyuan Lyu <changyuanl@google.com>

alioth/src/hv/hvf/bindings.rs

@@ -0,0 +1,19 @@
+// Copyright 2024 Google LLC
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#[link(name = "Hypervisor", kind = "framework")]
+extern "C" {
+    pub fn hv_vm_create(config: *mut i32) -> i32;
+    pub fn hv_vm_destroy() -> i32;
+}

alioth/src/hv/hvf/hvf.rs

@@ -12,20 +12,55 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+mod bindings;
 #[path = "vcpu/vcpu.rs"]
 mod vcpu;
 mod vm;
 
-use crate::hv::{Hypervisor, Result, VmConfig};
+use std::fmt::{Display, Formatter};
+use std::ptr::null_mut;
+
+use bindings::hv_vm_create;
+use snafu::ResultExt;
+
+use crate::hv::{error, Hypervisor, Result, VmConfig};
 
 use vm::HvfVm;
 
+#[derive(Debug, Clone, Copy)]
+#[repr(transparent)]
+pub struct HvReturn(i32);
+
+impl Display for HvReturn {
+    fn fmt(&self, f: &mut Formatter) -> std::fmt::Result {
+        write!(f, "{:#x}", self.0 as u32)
+    }
+}
+
+impl std::error::Error for HvReturn {}
+
+fn check_ret(ret: i32) -> std::io::Result<()> {
+    if ret == 0 {
+        return Ok(());
+    }
+    let kind = match (ret as u32) & 0xff {
+        3 => std::io::ErrorKind::InvalidInput,
+        5 => std::io::ErrorKind::NotFound,
+        7 => std::io::ErrorKind::PermissionDenied,
+        0xf => std::io::ErrorKind::Unsupported,
+        _ => std::io::ErrorKind::Other,
+    };
+    Err(std::io::Error::new(kind, HvReturn(ret)))
+}
+
 #[derive(Debug)]
 pub struct Hvf {}
 
 impl Hypervisor for Hvf {
     type Vm = HvfVm;
     fn create_vm(&self, _config: &VmConfig) -> Result<Self::Vm> {
-        unimplemented!()
+        let ret = unsafe { hv_vm_create(null_mut()) };
+        check_ret(ret).context(error::CreateVm)?;
+        Ok(HvfVm {})
     }
 }

alioth/src/hv/hvf/vm.rs

@@ -15,6 +15,8 @@
 use std::os::fd::{AsFd, BorrowedFd};
 use std::thread::JoinHandle;
 
+use crate::hv::hvf::bindings::hv_vm_destroy;
+use crate::hv::hvf::check_ret;
 use crate::hv::hvf::vcpu::HvfVcpu;
 use crate::hv::{
     GicV2, IoeventFd, IoeventFdRegistry, IrqFd, IrqSender, MemMapOption, MsiSender, Result, Vm,
@@ -173,6 +175,15 @@ impl GicV2 for HvfGicV2 {
 #[derive(Debug)]
 pub struct HvfVm {}
 
+impl Drop for HvfVm {
+    fn drop(&mut self) {
+        let ret = unsafe { hv_vm_destroy() };
+        if let Err(e) = check_ret(ret) {
+            log::error!("hv_vm_destroy: {e:?}");
+        }
+    }
+}
+
 impl Vm for HvfVm {
     type Vcpu = HvfVcpu;
     type Memory = HvfMemory;