ioctls: Rework run vp

Update run vp interface to not take a hv_message unnecessarily, and
work with the new MSHV_RUN_VP which takes a plain buffer.

Signed-off-by: Nuno Das Neves <[email protected]>

mshv-ioctls/src/ioctls/vcpu.rs

@@ -738,13 +738,14 @@ impl VcpuFd {
         Ok(0_usize)
     }
     ///  Triggers the running of the current virtual CPU returning an exit reason.
-    pub fn run(&self, mut hv_message_input: hv_message) -> Result<hv_message> {
+    pub fn run(&self) -> Result<hv_message> {
+        let mut msg = hv_message::default();
         // SAFETY: we know that our file is a vCPU fd and we verify the return result.
-        let ret = unsafe { ioctl_with_mut_ref(self, MSHV_RUN_VP(), &mut hv_message_input) };
+        let ret = unsafe { ioctl_with_mut_ref(self, MSHV_RUN_VP(), &mut msg) };
         if ret != 0 {
             return Err(errno::Error::last().into());
         }
-        Ok(hv_message_input)
+        Ok(msg)
     }
     /// Returns currently pending exceptions, interrupts, and NMIs as well as related
     /// states of the vcpu.
@@ -1481,10 +1482,9 @@ mod tests {
         ])
         .unwrap();
 
-        let hv_message: hv_message = unsafe { std::mem::zeroed() };
         let mut done = false;
         loop {
-            let ret_hv_message: hv_message = vcpu.run(hv_message).unwrap();
+            let ret_hv_message = vcpu.run().unwrap();
             match ret_hv_message.header.message_type {
                 hv_message_type_HVMSG_X64_HALT => {
                     println!("VM Halted!");

mshv-ioctls/src/mshv_ioctls.rs

@@ -10,7 +10,7 @@ ioctl_iow_nr!(MSHV_GET_VERSION_INFO, MSHV_IOCTL, 0x00, mshv_version_info);
 ioctl_iow_nr!(MSHV_CREATE_VP, MSHV_IOCTL, 0x04, mshv_create_vp);
 ioctl_iowr_nr!(MSHV_GET_VP_REGISTERS, MSHV_IOCTL, 0x05, mshv_vp_registers);
 ioctl_iow_nr!(MSHV_SET_VP_REGISTERS, MSHV_IOCTL, 0x06, mshv_vp_registers);
-ioctl_ior_nr!(MSHV_RUN_VP, MSHV_IOCTL, 0x07, hv_message);
+ioctl_ior_nr!(MSHV_RUN_VP, MSHV_IOCTL, 0x00, mshv_run_vp);
 #[cfg(target_arch = "x86_64")]
 ioctl_iowr_nr!(MSHV_GET_VP_STATE, MSHV_IOCTL, 0x0A, mshv_get_set_vp_state);
 #[cfg(target_arch = "x86_64")]