Increase IOAPIC_MAX_ID to 255 (from 254)
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Authored by emaste on May 10 2024, 6:10 PM.

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Reviewers

jhb
royger
kib

Commits

rGf952f27731ee: Increase IOAPIC_MAX_ID to 255 (from 254)
rG147c7e4dde23: Increase IOAPIC_MAX_ID to 255 (from 254)
rG18119e711f1c: Increase IOAPIC_MAX_ID to 255 (from 254)
rG4e3286818327: Increase IOAPIC_MAX_ID to 255 (from 254)

Summary

A test system here panicked with "madt_parse_apics: I/O APIC ID 255 too high". I/O APIC ID 255 is permissible.

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Repository

rG FreeBSD src repository

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Tests Not Applicable

Event Timeline

emaste requested review of this revision.May 10 2024, 6:10 PM

emaste created this revision.

kib accepted this revision.May 10 2024, 6:16 PM

This revision is now accepted and ready to land.May 10 2024, 6:16 PM

Might want a comment or a detail in the commit log that while the 0xff ID is used for broadcast IPIs for local APICs when not using x2APIC, IPIs aren't sent to I/O APICs, so it's ok for an I/O APIC to reuse that ID. Might also want to note that I/O APIC IDs haven't been meaningful since the 3-wire APIC bus which was last used by systems using Pentium CPUs.