Revert "virtio-devices, vmm: Optimised async virtio device activation"

This reverts commit f160572f9d.

There has been increased flakiness around the live migration tests since
this was merged. Speculatively reverting to see if there is increased
stability.

Signed-off-by: Rob Bradford <robert.bradford@intel.com>

vmm/src/device_manager.rs

@@ -79,12 +79,10 @@ use std::result;
 use std::sync::{Arc, Mutex};
 use std::time::Instant;
 use vfio_ioctls::{VfioContainer, VfioDevice};
+use virtio_devices::transport::VirtioPciDevice;
 use virtio_devices::transport::VirtioTransport;
-use virtio_devices::transport::{VirtioPciDevice, VirtioPciDeviceActivator};
 use virtio_devices::vhost_user::VhostUserConfig;
-use virtio_devices::{
-    AccessPlatformMapping, ActivateError, VdpaDmaMapping, VirtioMemMappingSource,
-};
+use virtio_devices::{AccessPlatformMapping, VdpaDmaMapping, VirtioMemMappingSource};
 use virtio_devices::{Endpoint, IommuMapping};
 use virtio_devices::{VirtioSharedMemory, VirtioSharedMemoryList};
 use vm_allocator::{AddressAllocator, SystemAllocator};
@@ -478,9 +476,6 @@ pub enum DeviceManagerError {
 
     /// Invalid identifier
     InvalidIdentifier(String),
-
-    /// Error activating virtio device
-    VirtioActivate(ActivateError),
 }
 pub type DeviceManagerResult<T> = result::Result<T, DeviceManagerError>;
 
@@ -944,9 +939,6 @@ pub struct DeviceManager {
 
     // Start time of the VM
     timestamp: Instant,
-
-    // Pending activations
-    pending_activations: Arc<Mutex<Vec<VirtioPciDeviceActivator>>>,
 }
 
 impl DeviceManager {
@@ -1088,7 +1080,6 @@ impl DeviceManager {
             io_uring_supported: None,
             boot_id_list,
             timestamp,
-            pending_activations: Arc::new(Mutex::new(Vec::default())),
         };
 
         let device_manager = Arc::new(Mutex::new(device_manager));
@@ -3529,7 +3520,6 @@ impl DeviceManager {
                 // The exception being if not on the default PCI segment.
                 pci_segment_id > 0 || device_type != VirtioDeviceType::Block as u32,
                 dma_handler,
-                self.pending_activations.clone(),
             )
             .map_err(DeviceManagerError::VirtioDevice)?,
         ));
@@ -3684,10 +3674,17 @@ impl DeviceManager {
     }
 
     pub fn activate_virtio_devices(&self) -> DeviceManagerResult<()> {
-        for mut activator in self.pending_activations.lock().unwrap().drain(..) {
-            activator
-                .activate()
-                .map_err(DeviceManagerError::VirtioActivate)?;
+        // Find virtio pci devices and activate any pending ones
+        let device_tree = self.device_tree.lock().unwrap();
+        for pci_device_node in device_tree.pci_devices() {
+            #[allow(irrefutable_let_patterns)]
+            if let PciDeviceHandle::Virtio(virtio_pci_device) = &pci_device_node
+                .pci_device_handle
+                .as_ref()
+                .ok_or(DeviceManagerError::MissingPciDevice)?
+            {
+                virtio_pci_device.lock().unwrap().maybe_activate();
+            }
         }
         Ok(())
     }