Make savestate optional. Fix test. Have subchannel read from primary.

Author: erfrimod

vm/devices/net/netvsp/src/lib.rs

@@ -800,7 +800,7 @@ impl PrimaryChannelState {
         tx_spread_sent: bool,
         guest_link_down: bool,
         pending_link_action: Option<bool>,
-        packet_filter: u32,
+        packet_filter: Option<u32>,
     ) -> Result<Self, NetRestoreError> {
         // Restore control messages.
         let control_messages_len = control_messages.iter().map(|msg| msg.data.len()).sum();
@@ -880,6 +880,8 @@ impl PrimaryChannelState {
             PendingLinkAction::Default
         };
 
+        let packet_filter = packet_filter.unwrap_or(rndisprot::NPROTO_PACKET_FILTER);
+
         Ok(Self {
             guest_vf_state,
             is_data_path_switched: None,
@@ -1198,7 +1200,24 @@ impl VmbusDevice for Nic {
             .adapter
             .num_sub_channels_opened
             .fetch_add(1, Ordering::SeqCst);
-        let packet_filter = rndisprot::NDIS_PACKET_TYPE_NONE; // No traffic until guest sets filter.
+
+        let packet_filter = if channel_idx == 0 {
+            // No rx traffic on primary channel until guest sets filter.
+            rndisprot::NDIS_PACKET_TYPE_NONE
+        } else {
+            // Subchannel inherits the packet filter of the primary channel.
+            // Stop the primary worker task temporarily to safely access the state.
+            let coordinator = self.coordinator.state_mut().unwrap();
+            coordinator.workers[0].stop().await;
+            let packet_filter = coordinator.workers[0]
+                .state()
+                .unwrap()
+                .channel
+                .packet_filter;
+            coordinator.workers[0].start();
+            packet_filter
+        };
+
         let r = self.insert_worker(channel_idx, open_request, state, true, packet_filter);
         if channel_idx != 0
             && num_opened + 1 == self.coordinator.state_mut().unwrap().num_queues as usize
@@ -1828,7 +1847,7 @@ impl Nic {
                         tx_spread_sent: primary.tx_spread_sent,
                         guest_link_down: !primary.guest_link_up,
                         pending_link_action,
-                        packet_filter: primary.packet_filter,
+                        packet_filter: Some(primary.packet_filter),
                     })
                 }
             };

vm/devices/net/netvsp/src/saved_state.rs

@@ -121,7 +121,7 @@ pub struct ReadyPrimary {
     #[mesh(15)]
     pub pending_link_action: Option<bool>,
     #[mesh(16)]
-    pub packet_filter: u32,
+    pub packet_filter: Option<u32>,
 }
 
 #[derive(Debug, Protobuf)]

vm/devices/net/netvsp/src/test.rs

@@ -4354,6 +4354,29 @@ async fn set_rss_parameter_bufs_not_evenly_divisible(driver: DefaultDriver) {
         .await
         .expect("association packet");
 
+    // Set packet filter
+    channel
+        .send_rndis_control_message(
+            rndisprot::MESSAGE_TYPE_SET_MSG,
+            rndisprot::SetRequest {
+                request_id: 0,
+                oid: rndisprot::Oid::OID_GEN_CURRENT_PACKET_FILTER,
+                information_buffer_length: size_of::<u32>() as u32,
+                information_buffer_offset: size_of::<rndisprot::SetRequest>() as u32,
+                device_vc_handle: 0,
+            },
+            &rndisprot::NPROTO_PACKET_FILTER.to_le_bytes(),
+        )
+        .await;
+
+    let set_complete: rndisprot::SetComplete = channel
+        .read_rndis_control_message(rndisprot::MESSAGE_TYPE_SET_CMPLT)
+        .await
+        .unwrap();
+
+    assert_eq!(set_complete.request_id, 0);
+    assert_eq!(set_complete.status, rndisprot::STATUS_SUCCESS);
+
     let message = NvspMessage {
         header: protocol::MessageHeader {
             message_type: protocol::MESSAGE5_TYPE_SUB_CHANNEL,