msi - Message Signaled Interrupt
Messaged Signaled Interrupts are used in modern PCI as well as
some ARM GIC controllers. MSI objects allow a privileged userspace
process to allocate a range of MSIs and associated IRQ vectors for
use with device drivers to allocate
The most common use for an MSI object is to allocate a range of MSIs
to provide to a PCI device's Message Signaled Interrupt Capability.
Subsequently, the platform or PCI bus driver may use this object to
interrupt objects corresponding to those MSIs for use
in downstream device drivers.