virtio/vsock: support MSG_EOR bit processing

If packet has 'EOR' bit - set MSG_EOR in 'recvmsg()' flags.
Signed-off-by: NArseny Krasnov <arseny.krasnov@kaspersky.com>
Reviewed-by: NStefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/r/20210903123251.3273639-1-arseny.krasnov@kaspersky.comSigned-off-by: NMichael S. Tsirkin <mst@redhat.com>

net/vmw_vsock/virtio_transport_common.c

@@ -76,8 +76,12 @@ virtio_transport_alloc_pkt(struct virtio_vsock_pkt_info *info,
 			goto out;
 
 		if (msg_data_left(info->msg) == 0 &&
-		    info->type == VIRTIO_VSOCK_TYPE_SEQPACKET)
+		    info->type == VIRTIO_VSOCK_TYPE_SEQPACKET) {
 			pkt->hdr.flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOM);
+
+			if (info->msg->msg_flags & MSG_EOR)
+				pkt->hdr.flags |= cpu_to_le32(VIRTIO_VSOCK_SEQ_EOR);
+		}
 	}
 
 	trace_virtio_transport_alloc_pkt(src_cid, src_port,
@@ -460,6 +464,9 @@ static int virtio_transport_seqpacket_do_dequeue(struct vsock_sock *vsk,
 		if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOM) {
 			msg_ready = true;
 			vvs->msg_count--;
+
+			if (le32_to_cpu(pkt->hdr.flags) & VIRTIO_VSOCK_SEQ_EOR)
+				msg->msg_flags |= MSG_EOR;
 		}
 
 		virtio_transport_dec_rx_pkt(vvs, pkt);