hypervisor: Refactor create_passthrough_device() for generic type

Changed the return type of create_passthrough_device() to generic type
hypervisor::Device.

Signed-off-by: Michael Zhao <michael.zhao@arm.com>

hypervisor/src/device.rs

@@ -10,6 +10,7 @@
 //
 
 use crate::DeviceAttr;
+use std::os::unix::io::AsRawFd;
 use thiserror::Error;
 
 #[derive(Error, Debug)]
@@ -33,7 +34,7 @@ pub type Result<T> = std::result::Result<T, HypervisorDeviceError>;
 ///
 /// This crate provides a hypervisor-agnostic interfaces for device
 ///
-pub trait Device: Send + Sync {
+pub trait Device: Send + Sync + AsRawFd {
     /// Set device attribute.
     fn set_device_attr(&self, attr: &DeviceAttr) -> Result<()>;
 }

hypervisor/src/kvm/mod.rs

@@ -9,6 +9,7 @@
 //
 
 use kvm_ioctls::{NoDatamatch, VcpuFd, VmFd};
+use std::os::unix::io::{AsRawFd, RawFd};
 use std::result;
 use std::sync::Arc;
 #[cfg(target_arch = "x86_64")]
@@ -303,15 +304,14 @@ impl vm::Vm for KvmVm {
         self.fd.check_extension(c)
     }
     /// Create a device that is used for passthrough
-    fn create_passthrough_device(&self) -> vm::Result<DeviceFd> {
+    fn create_passthrough_device(&self) -> vm::Result<Arc<dyn device::Device>> {
         let mut vfio_dev = kvm_create_device {
             type_: kvm_device_type_KVM_DEV_TYPE_VFIO,
             fd: 0,
             flags: 0,
         };
 
-        self.fd
-            .create_device(&mut vfio_dev)
+        self.create_device(&mut vfio_dev)
             .map_err(|e| vm::HypervisorVmError::CreatePassthroughDevice(e.into()))
     }
 }
@@ -869,3 +869,9 @@ impl device::Device for KvmDevice {
             .map_err(|e| device::HypervisorDeviceError::SetDeviceAttribute(e.into()))
     }
 }
+
+impl AsRawFd for KvmDevice {
+    fn as_raw_fd(&self) -> RawFd {
+        self.fd.as_raw_fd()
+    }
+}

hypervisor/src/vm.rs

@@ -14,7 +14,7 @@ use crate::cpu::Vcpu;
 use crate::device::Device;
 #[cfg(target_arch = "x86_64")]
 use crate::ClockData;
-use crate::{CreateDevice, DeviceFd, IoEventAddress, IrqRoutingEntry, MemoryRegion};
+use crate::{CreateDevice, IoEventAddress, IrqRoutingEntry, MemoryRegion};
 use kvm_ioctls::Cap;
 use std::sync::Arc;
 use thiserror::Error;
@@ -178,5 +178,5 @@ pub trait Vm: Send + Sync {
     /// Checks if a particular `Cap` is available.
     fn check_extension(&self, c: Cap) -> bool;
     /// Create a device that is used for passthrough
-    fn create_passthrough_device(&self) -> Result<DeviceFd>;
+    fn create_passthrough_device(&self) -> Result<Arc<dyn Device>>;
 }

vmm/src/device_manager.rs

@@ -57,6 +57,8 @@ use std::fs::{File, OpenOptions};
 use std::io::{self, sink, stdout, Seek, SeekFrom};
 use std::num::Wrapping;
 use std::os::unix::fs::OpenOptionsExt;
+#[cfg(feature = "pci_support")]
+use std::os::unix::io::FromRawFd;
 use std::path::PathBuf;
 use std::result;
 use std::sync::{Arc, Mutex};
@@ -745,7 +747,7 @@ pub struct DeviceManager {
 
     // Passthrough device handle
     #[cfg(feature = "pci_support")]
-    passthrough_device: Option<Arc<DeviceFd>>,
+    passthrough_device: Option<Arc<dyn hypervisor::Device>>,
 
     // Paravirtualized IOMMU
     #[cfg(feature = "pci_support")]
@@ -2390,11 +2392,11 @@ impl DeviceManager {
         &mut self,
         pci: &mut PciBus,
         interrupt_manager: &Arc<dyn InterruptManager<GroupConfig = MsiIrqGroupConfig>>,
-        device_fd: &Arc<DeviceFd>,
+        device: &Arc<dyn hypervisor::Device>,
         device_cfg: &mut DeviceConfig,
     ) -> DeviceManagerResult<(u32, String)> {
         #[cfg(feature = "kvm")]
-        return self.add_vfio_device(pci, interrupt_manager, device_fd, device_cfg);
+        return self.add_vfio_device(pci, interrupt_manager, device, device_cfg);
 
         #[cfg(not(feature = "kvm"))]
         Err(DeviceManagerError::NoDevicePassthroughSupport)
@@ -2405,7 +2407,7 @@ impl DeviceManager {
         &mut self,
         pci: &mut PciBus,
         interrupt_manager: &Arc<dyn InterruptManager<GroupConfig = MsiIrqGroupConfig>>,
-        device_fd: &Arc<DeviceFd>,
+        device: &Arc<dyn hypervisor::Device>,
         device_cfg: &mut DeviceConfig,
     ) -> DeviceManagerResult<(u32, String)> {
         // We need to shift the device id since the 3 first bits
@@ -2420,7 +2422,10 @@ impl DeviceManager {
 
         let memory = self.memory_manager.lock().unwrap().guest_memory();
         let vfio_container = Arc::new(
-            VfioContainer::new(device_fd.clone()).map_err(DeviceManagerError::VfioCreate)?,
+            VfioContainer::new(Arc::new(unsafe {
+                DeviceFd::from_raw_fd(device.as_raw_fd())
+            }))
+            .map_err(DeviceManagerError::VfioCreate)?,
         );
 
         let vfio_device = VfioDevice::new(
@@ -2511,17 +2516,16 @@ impl DeviceManager {
 
         if let Some(device_list_cfg) = &mut devices {
             // Create the passthrough device handle
-            let device_fd = self
+            let device = self
                 .address_manager
                 .vm
                 .create_passthrough_device()
                 .map_err(|e| DeviceManagerError::CreatePassthroughDevice(e.into()))?;
-            let device_fd = Arc::new(device_fd);
-            self.passthrough_device = Some(Arc::clone(&device_fd));
+            self.passthrough_device = Some(Arc::clone(&device));
 
             for device_cfg in device_list_cfg.iter_mut() {
                 let (device_id, _) =
-                    self.add_passthrough_device(pci, interrupt_manager, &device_fd, device_cfg)?;
+                    self.add_passthrough_device(pci, interrupt_manager, &device, device_cfg)?;
                 if device_cfg.iommu && self.iommu_device.is_some() {
                     iommu_attached_device_ids.push(device_id);
                 }
@@ -2936,26 +2940,25 @@ impl DeviceManager {
 
         let interrupt_manager = Arc::clone(&self.msi_interrupt_manager);
 
-        let device_fd = if let Some(device_fd) = &self.passthrough_device {
-            Arc::clone(&device_fd)
+        let device = if let Some(device) = &self.passthrough_device {
+            Arc::clone(&device)
         } else {
             // If the passthrough device file descriptor has not been created yet,
             // it is created here and stored in the DeviceManager structure for
             // future needs.
-            let device_fd = self
+            let device = self
                 .address_manager
                 .vm
                 .create_passthrough_device()
                 .map_err(|e| DeviceManagerError::CreatePassthroughDevice(e.into()))?;
-            let device_fd = Arc::new(device_fd);
-            self.passthrough_device = Some(Arc::clone(&device_fd));
-            device_fd
+            self.passthrough_device = Some(Arc::clone(&device));
+            device
         };
 
         let (device_id, device_name) = self.add_passthrough_device(
             &mut pci.lock().unwrap(),
             &interrupt_manager,
-            &device_fd,
+            &device,
             device_cfg,
         )?;