MADT is used to specify the GSI base for each IO-APIC and the number of
interrupt pins per IO-APIC is programmed into Max. Redir. Entry register of
that IO-APIC.
On platforms with multiple IO-APICs, there can be holes in the GSI space.
For example, on a platform with 2 IO-APICs, the following configuration has
a hole (from 24 to 31) in the GSI space.
IO-APIC 1: GSI base - 0, number of pins - 24
IO-APIC 2: GSI base - 32, number of pins - 8
This patch also adjusts the size for variables used to represent the total
number of IO-APICs on the system from uint16_t to uint8_t as the ACPI MADT
uses only 8-bits to indicate the unique IO-APIC IDs.
Tracked-On: #4151
Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com>
Acked-by: Eddie Dong <eddie.dong@Intel.com>
f3cf93656a