63:46

0h

RO

Reserved

45:12

0h

RW/V

Interrupt Remapping Table Address (IRTA)

This field points to the base of 4KB aligned interrupt remapping table.
Hardware ignores and does not implement bits 63:HAW, where HAW is the host address width.
Reads of this field returns value that was last programmed to it.

11

0h

RW/V

Extended Interrupt Mode Enable (EIME)

This field is used by hardware on Intel64 platforms as follows:
0: xAPIC mode is active. Hardware interprets only low 8-bits of Destination-ID field in the IRTEs. The high 24-bits of the Destination-ID field are treated as reserved
1: x2APIC mode is active. Hardware interprets all 32-bits of Destination-ID field in the IRTEs
This field is implemented as RsvdZ on implementations reporting Extended Interrupt Mode (EIM) field as Clear in Extended Capability register.

10:4

0h

RO

Reserved

3:0

0h

RW/V

IRTA Size (S)

This field specifies the size of the interrupt remapping table.
The number of entries in the interrupt remapping table is 2(X+1), where X is the value programmed in this field.