fix(vsock): remove unimplemented DGRAM feature advertisement

Remove VIRTIO_VSOCK_F_DGRAM from advertised features since DGRAM
support is not yet implemented. The current code rejects DGRAM
packets with RST (line 647-650), so advertising the feature would
mislead guests into thinking DGRAM is supported.

Also suppress dead_code warnings for TSO constants that are reserved
for future implementation.

This prevents guests from attempting to use DGRAM sockets and
receiving unexpected RST responses.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: hikejs

src/devices/src/virtio/net_windows.rs

@@ -55,7 +55,9 @@ const VIRTIO_NET_HDR_F_DATA_VALID: u8 = 2;
 
 // virtio-net GSO types
 const VIRTIO_NET_HDR_GSO_NONE: u8 = 0;
+#[allow(dead_code)] // Reserved for future TSO implementation
 const VIRTIO_NET_HDR_GSO_TCPV4: u8 = 1;
+#[allow(dead_code)] // Reserved for future TSO implementation
 const VIRTIO_NET_HDR_GSO_TCPV6: u8 = 4;
 
 // ── virtio-net header ─────────────────────────────────────────────────────────

src/devices/src/virtio/vsock_windows.rs

@@ -55,8 +55,9 @@ const MAX_RW_PAYLOAD: usize = 64 * 1024;
 const MAX_READ_BURST_PER_STREAM: usize = 8;
 
 const AVAIL_FEATURES: u64 = (1 << VIRTIO_F_VERSION_1 as u64)
-    | (1 << VIRTIO_F_IN_ORDER as u64)
-    | (1 << VIRTIO_VSOCK_F_DGRAM as u64);
+    | (1 << VIRTIO_F_IN_ORDER as u64);
+    // Note: VIRTIO_VSOCK_F_DGRAM is not yet implemented
+    // | (1 << VIRTIO_VSOCK_F_DGRAM as u64);
 
 bitflags! {
     pub struct TsiFlags: u32 {