VTD_FLAG_IRQ_REMAP_PRE_ENABLED
iommu->flags |= VTD_FLAG_IRQ_REMAP_PRE_ENABLED;
return (iommu->flags & VTD_FLAG_IRQ_REMAP_PRE_ENABLED);
iommu->flags &= ~VTD_FLAG_IRQ_REMAP_PRE_ENABLED;