if ((error = vlib_pci_read_config_u8 (vm, h, PCI_CAPABILITY_LIST, &pos)))
{
virtio_log_error (vif, "error in reading capabilty list position");
if ((error = vlib_pci_read_config_u8 (vm, h, PCI_CAPABILITY_LIST, &pos)))
{
virtio_log_error (vif, "error in reading capabilty list position");