fix(net): set tap offload features on restore

Set tap offload features on restore.

Signed-off-by: Nikita Kalyazin <kalyazin@amazon.com>

src/vmm/src/devices/virtio/net/device.rs

@@ -669,7 +669,7 @@ impl Net {
 
     /// Builds the offload features we will setup on the TAP device based on the features that the
     /// guest supports.
-    fn build_tap_offload_features(guest_supported_features: u64) -> u32 {
+    pub fn build_tap_offload_features(guest_supported_features: u64) -> u32 {
         let add_if_supported =
             |tap_features: &mut u32, supported_features: u64, tap_flag: u32, virtio_flag: u32| {
                 if supported_features & (1 << virtio_flag) != 0 {

src/vmm/src/devices/virtio/net/persist.rs

@@ -11,7 +11,7 @@ use serde::{Deserialize, Serialize};
 use utils::net::mac::MacAddr;
 
 use super::device::Net;
-use super::NET_NUM_QUEUES;
+use super::{TapError, NET_NUM_QUEUES};
 use crate::devices::virtio::device::DeviceState;
 use crate::devices::virtio::persist::{PersistError as VirtioStateError, VirtioDeviceState};
 use crate::devices::virtio::queue::FIRECRACKER_MAX_QUEUE_SIZE;
@@ -65,6 +65,8 @@ pub enum NetPersistError {
     VirtioState(#[from] VirtioStateError),
     /// Indicator that no MMDS is associated with this device.
     NoMmdsDataStore,
+    /// Setting tap interface offload flags failed: {0}
+    TapSetOffload(TapError),
 }
 
 impl Persist<'_> for Net {
@@ -129,6 +131,11 @@ impl Persist<'_> for Net {
         net.acked_features = state.virtio_state.acked_features;
 
         if state.virtio_state.activated {
+            let supported_flags: u32 = Net::build_tap_offload_features(net.acked_features);
+            net.tap
+                .set_offload(supported_flags)
+                .map_err(NetPersistError::TapSetOffload)?;
+
             net.device_state = DeviceState::Activated(constructor_args.mem);
         }