anchor.diff:  
   (defun virtio-net-register (device)
     (sup:debug-print-line "Detected virtio net device " device)
  -  (let* ((nic (make-virtio-net :virtio-device device
  -                               :boot-id (sup:current-boot-id)))
  +  (let* ((nic (make-instance 'virtio-net
  +                             :virtio-device device
  +                             :boot-id (sup:current-boot-id)))
            (irq-handler (sup:make-simple-irq (virtio:virtio-device-irq device)
                                              (virtio-net-irq-latch nic))))
       (setf (virtio-net-irq-handler-function nic) irq-handler)
  
positive.code:          (return))
         (virtio-net-transmit-real nic (pop (virtio-net-real-tx-pending nic))))))
  
  (defun virtio-net-transmit (nic packet)
    (let* ((len (loop for elt in packet
                   summing (length elt)))
           (data (make-array len
  
negative.code: and then some alignment.")
  (defconstant +virtio-net-n-tx-buffers+ 32)
  
  (defclass virtio-net (nic:network-card)
    ((%mac :accessor virtio-net-mac :initarg :mac :reader nic:mac-address)
     (%virtio-device :accessor virtio-net-virtio-device :initarg :virtio-device)
     (%boot-id :accessor virtio-net-boot-id :initarg :boot-id)
     (%lock :accessor virtio-net-lock :initform (sup:make-mutex "Virtio-Net NIC lock"))
     (%irq-latch :accessor virtio-net-irq-latch :initform (sup:make-latch "Virtio-Net NIC IRQ latch"))
     (%irq-handler-function :accessor virtio-net-irq-handler-function :initarg :irq-handler-function)
     (%worker-thread :accessor virtio-net-worker-thread :initarg :worker-thread)
     (%tx-virt :accessor virtio-net-tx-virt :initarg :tx-virt)
     (%tx-phys :accessor virtio-net-tx-phys :initarg :tx-phys)
     (%free-tx-buffers :accessor virtio-net-free-tx-buffers :initform nil)
     ;; Preallocated wired conses usable in the PA TX processing.
     (%tx-buffer-freelist :accessor virtio-net-tx-buffer-freelist :initform nil)
     ;; Packets waiting to be transmitted.
     (%tx-pending :accessor virtio-net-tx-pending :initform '())
     (%real-tx-pending :accessor virtio-net-real-tx-pending :initform '())
     (%rx-virt :accessor virtio-net-rx-virt :initarg :rx-virt)
     (%rx-phys :accessor virtio-net-rx-phys :initarg :rx-phys)
     (%total-rx-bytes :accessor virtio-net-total-rx-bytes :initform 0)
     (%total-tx-bytes :accessor virtio-net-total-tx-bytes :initform 0)
     (%total-rx-packets :accessor virtio-net-total-rx-packets :initform 0)
     (%total-tx-packets :accessor virtio-net-total-tx-packets :initform 0)))
  
  (defun check-virtio-net-boot (nic)
    (when (not (eql (virtio-net-boot-id nic) (sup:current-boot-id)))
  