IXGBE_VT_CTL
if (!(IXGBE_READ_REG(hw, IXGBE_VT_CTL) & IXGBE_VT_CTL_VT_ENABLE))
vtctl = IXGBE_READ_REG(hw, IXGBE_VT_CTL);
IXGBE_WRITE_REG(hw, IXGBE_VT_CTL, vtctl);
vtctl = IXGBE_READ_REG(hw, IXGBE_VT_CTL);
IXGBE_WRITE_REG(hw, IXGBE_VT_CTL, vtctl);